United States
Environmental Protection
Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
EPA-600/8-81-007
April 1981
Research and Development
Operation Manual for
Automatic
Dichotomous
Samplers
Application to
Beckman Dichotomous
Samplers
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EPA 600/8-81-007
March 1981
OPERATION MANUAL FOR AUTOMATIC DICHOTOMOUS SAMPLERS
Application to Beckman Dichotomous Samplers
John D. Spengler, Ph.D., William A. Turner,
F. Peter Fairchild, and Jane E. Slaughter
Harvard School of Public Health
Department of Environmental Health Sciences
Boston, Massachusetts 02115
and
Thomas G. Dzubay
Atmospheric Chemistry and Physics Division
Environmental Sciences Research Laboratory
Research Triangle Park, N.C. 27711
Contract No. D4806NAST
Project Officer
Thomas G. Dzubay
Atmospheric Chemistry and Physics Division
Environmental Sciences Research Laboratory
Research Triangle Park, N.C. 27711
ENVIRONMENTAL SCIENCES RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, N.C. 27711
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DISCLAIMER
This report has been reviewed by the Environmental Sciences Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
n
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ABSTRACT
The Beckman automatic dichotomous sampler is one of several samplers
currently available that simultaneously collects coarse and fine atmospheric
particles. These instruments are becoming more widely used to support
research and regulatory studies that require information on size fractionated
particles. The operating manual is intended for use by technicians and
operators of the Beckman sampler. It presents discussions of the nature of
atmospheric particles and the basic operating principles as a means of
providing operators with a more complete understanding of the instrument and
its uses.
Factors to be considered in site selection are discussed, followed by
instructions for installation and checkout once the most suitable site has
been identified. Special attention is given to checking for leaks in the flow
system, as field experience has shown this to be a potential problem. Other
areas of concern such as operating instructions, calibration techniques,
maintenance schedules, quality assurance, and trouble shooting are also
addressed.
The manual should serve as an effective supplement to information given
in the manufacturer's instruction manual. Various modifications to original
equipment and instructions that will simplify and improve performance are
described, including lists of parts and suggested suppliers. Areas of
uncertainty about the design or performance are identified. The manual will
be revised and updated as further field experience and research results become
available.
This report was submitted in fulfillment of Contract No. D4806NAST by John D.
Spengler under the sponsorship of the U.S. Environmental Protection Agency,
This report was completed as of December 31, 1979.
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CONTENTS
Abstract iii
Special Note iy
Figures yii
Tables viii
Acknowledgements ix
1. Introduction 1
Nature of Atmospheric Particles 1
Description of the Instrument 3
Instrument Specifications 5
Purpose and Use of Document 5
2. Principles of Operation 7
Sampler Inlet 7
Virtual Impactor . 9
Sampling Flow System 9
Filters 11
Filter Change Mechanism 14
Temperature Control System 17
Sampler Control System 18
3. Considerations in Site Selection 21
Siting Criteria 21
Installation Requirements 23
4. Installation Procedure 25
Delivery and Unpacking 25
Sampler Installations 25
5. Checkout and Calibration 31
Instructions for Sampler Checkout 31
Instrument Calibrations 34
Calibrations Using Rotameters 34
Calibrations Using A Dry Test Meter 44
Filter Overload Sensing Switch Setting 47
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CONTENTS (continued)
6. Operating Procedures 50
Sampler Housing 50
Front Panel Controls 51
Interior Flow Controls 53
Operating Instructions 53
Simplified Operating Instructions 62
Sampler Operation 64
Keypad Operation 68
7. Quality Assurance 72
8. Maintenance 78
Schedule for Routine Maintenance 78
Maintenance Instructions - Yearly Maintenance 79
Maintenance Instructions - Semiannual Maintenance 80
9. Troubleshooting 83
References 84
Appendices
I. Parts and Accessories 85
II. Correction of Rotameter Readings to Actual
Pressure and Temperature 90
VI
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FIGURES
Number Page
1 Size distribution of fine and coarse atmospheric particles. ... 2
2 Sampler showing housing and standpipe 4
3 Sampler with front cover removed 8
4 Sketch of virtual impactor 10
5 Impactor collection efficiency versus particle size 10
6 Sampler flow system 12
7 Filter tray assembly 13
8 Interior of sampler showing filter change mechanism 15
9 Sketch of filter change mechanism 16
10 Temperature control ranges and switch actuating temperatures. . . 19
11 Electronic control system diagram 19
12 Interior of sampler with impactor installed 27
13 Standpipe extension and supporting sleeve 28
14 Fine flow calibration at base using 604 rotameter 36
15 Fine flow calibration at inlet using 604 rotameter 38
16 Coarse flow calibration at base using 603 rotameter 39
17a Fine flow calibration forms 41
17b Coarse flow calibration forms 42
18 Calibration using Singer dry test meter 45
19 Sampler front panel controls 52
20 Interior flow controls 54
21a Julian calendar for non-leap year 57
21b Julian calendar for leap years 58
22 Example of printer printout showing programmed input
instructions and operational outputs 66
23 Typical printer output for interrupt cycle 69
24 Suggested weekly log form 74
25 Suggested sample flow audit form 75
26 Virtual impactor dissassembled for cleaning 81
A-l Viscosity (Centipoise) of air as a function of temperature 93
A-2 Percent of flow correction factor for viscosity changes 94
Vll
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TABLES
Number Page
1 Topographic and meteorological influences on local dispersion ... 22
2 Source configuration and its influence on dichotomous
sampling 23
vm
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ACKNOWLEDGEMENTS
The authors wish to express their appreciation to Beckman Instruments
Incorporated for permission to use printed materials from their instruction
manual.
ix
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SECTION 1
INTRODUCTION
NATURE OF ATMOSPHERIC PARTICLES
This report describes the operation, calibration, and maintenance of the
Beckman Automatic Dichotomous Sampler. This is one of several dichotomous
samplers available, all of which are designed to collect simultaneously coarse
and fine atmospheric particulates. Both coarse and fine particles are of
special interest because the bimodal distribution of particles in the
atmosphere reflects differences in sources (see Figure 1). In general,
grinding, abrasion, and mechanical crushing produce particles in the coarse
mode approximately 2.5 urn in diameter and larger. Particles in the
accumulation of fine size range are in general formed from combustion either
directly or by gas to aerosol conversion. These fine sized particles are
believed to be of greater concern for health effects because they will more
readily penetrate to the deeper portions of the lungs.
Because of the differences in mechanisms of formation, fine and coarse
particles generally have distinctly different chemical compositions. Many of
the elements found in the soil, such as silicon, calcium, iron, and aluminum,
generally appear in the coarse particle mode. Products of combustion activity
such as sulfates, nitrates, organics, lead and soot are generally found in the
fine particle fraction.
Once suspended in the atmosphere particles are subject to gravitational,
diffusional and other forces as well as cloud forming processes that
continually modify their distribution. As a result, the ultra fine particles
are agglomerating and growing in size, thus adding to the fine particles in
the accumulation mode from .1 to 2.5 urn in diameter. Gravitational settling
-------
C/)
C/)
<
cc
HI
LU
1-0 10-
PARTICLE DIAMETER, jam
Figure 1. Size distribution and chemical composition of fine and coarse
atmospheric particles (1)
-------
and inertia! impact!on act on larger particles to remove them from the
atmosphere. Although at times there will be particles as large as 50 (jm to
100 urn suspended in the lower atmosphere, the mass of these coarse fraction
particles is distributed around 10 urn in diameter. The dichotomous sampler
was specifically designed to collect suspended particulate matter separately
in both the fine and coarse size ranges. This is consistent with particle size
distributions in the atmosphere and the retention of particles in the upper
and lower human respiratory tract.
Since the dichotomous sampler collects the fine and coarse particles on
separate filters, these filters can be used in subsequent analysis.
Techniques such as x-ray fluorescence (XRF) provide information on
approximately 20 elements. Ion chromatography can identify sulfate, nitrate,
and ammonium ions, among others. This information is valuable in identifying
source contributions to ambient concentrations and the toxicity due to
specific metals or compounds. Sampling of the fine and coarse fraction may
aid the assessment of visibility reduction problems and fugitive dusts.
DESCRIPTION OF THE INSTRUMENT
This report describes the operation and calibration of the Beckman
Automated Dichotomous Particulate Sampling System, hereafter referred to as
the dichotomous sampler or the Beckman sampler. All components except for the
inlet are housed in a weather resistant, internally heated enclosure, shown in
Figure 2. Air is drawn into the instrument through the fractionating inlet,
which is designed so that particles larger than approximately 15 urn are
excluded. The air sample next flows through a virtual impactor, which
simultaneously separates the particles into a fine fraction and coarse
fraction. The two size fractions are then deposited on separate filters for
subsequent analysis. Air flow through the sampler is maintained by separate
fine and coarse flow systems.
An important feature of the Beckman dichotomous sampler is its
microprocessor control system, which allows for automated continuous sampling.
Two filter trays, each containing 36 filters, are placed in the sample changer
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FRACTIONATING INLET
SAMPLING STANDPIPE
INSTRUMENT SHELTER
Figure 2. Beckman Automated Dichotomous Sampler, Showing Housing, Standpipe,
and Fractionating Inlet in Operating Position
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(see Figure 7). The sampler can then be programmed to collect automatically
35 pairs of samples, at preselected times and sampling intervals. (One pair of
filters is always maintained unexposed as a control.) A heater/thermostat
system maintains the internal temperature at 33°C and permits sampling through
variations in ambient temperatures of -40°C to +50°C.
A more detailed discussion of instrument subsystems and operating
principles is provided in Section 2 of this report. Instrument specifications
are given below.
PURPOSE AND USE OF DOCUMENT
This report is primarily for use by those responsible for establishing
and operating dichotomous sampler networks and for field personnel responsible
for maintenance and calibration of the Beckman sampler. The report is designed
to provide background information and descriptions of how the sampler works
and suggestions for its use. Considerations for site selection are provided
along with installation instructions. Calibration, operation and maintenance
procedures are presented, along with suggested quality assurance and data
handling procedures. The information is based on materials provided by the
manufacturer along with the results of extensive field use of the instrument.
It is expected that the manufacturer's instruction manual (2), including
trouble shooting procedures and instrument schematics diagrams, will be
available to the user of this report.
SPECIFICATIONS
Inlet Upper Cutoff Point (50%): 15 urn nominal; 12 to 18 urn for wind
speeds below 20 km/hr
Virtual Impactor Cut Point (50%): 2.5 urn
Virtual Impactor Losses: <5% for particles between 1 and 15 pm
aerodynamic diameter; <15% at cut point
Sample Flow Rate: 16.7 £/min total (1 cubic meter per hr)
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Sample Flow Stability:
Timing Accuracy:
Start Time Selction:
Delay Period Between Samples
or Sample Groups:
Number of Filters per Group:
Filter Material:
Filter Size:
Number of Filters:
Housing:
Ambient Operating Temperature Range:
Operating Humidity Range:
Power Required:
Power Failure:
Power Cord:
Dimensions:
Instrument Weight:
Shipping Weight:
±5% per week
±2 min per day
Presettable to any number of days,
hours, or minutes up to 365, 23, and
59, respectively
Presettable to any number of days,
hours or minutes up to 364, 23, 59
Presettable from 1 to 36 filters
I urn Teflon standard, 2 urn optional
29 urn deposit dia. on 5 cm x 5 cm
square frame
36 pair in 2 trays
Weathertight; internally temperature
controlled at 33°C
-40° to +122°F (-40° to +50°C)
0 to 100% RH
115 VAC, 60 Hz; 200 VA nominal at 25°C
with pumps off; 300 VA max at 25°C with
pumps on; 850 VA max with heaters and
pumps on
Battery pack maintains timekeeping
function for 30 min should power fail;
time of power failure is printed
8 ft (2.4 m) long, U-ground plug
40 in. H x 26 in. W x 19% in. D (102 x
66 x 50 cm); plus inlet protrudes 20
in. (51 cm) from top
175 Ib (80 kg)
220 Ib (100 kg)
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SECTION 2
PRINCIPLES OF OPERATION
This section gives an explanation of the principles of operation for the
six main components of the dichotomous sampler: fractionating inlet, virtual
impactor, sample flow system, filter system, temperature control system and
sampler control system. Figure 3 shows the major subassemblies which are
readily visible with the front cover removed.
SAMPLER INLET
The air sample enters the fractionating inlet, which protrudes from the
top of the sampler housing as shown in Figure 2. Because the bell shaped
inlet has axial symmetry, the sampling efficiency is independent of wind
direction. With air entering through the bottom of the inlet, rain is kept
out, and a coarse screen keeps large particles and insects from being
entrained. The inlet is designed so that particles greater than 30 urn will not
enter. Particles between about 15 pm and 30 (jm have, a settling velocity
roughly equivalent to the average upward velocity of the inlet so that these
particles settle out of the inlet and do not enter the impactor (3); thus the
inlet 50% cutpoint is 15 pm, i.e., the inlet is approximately 50 % efficient
at collecting 15 pm particles. It should be noted that wind speed does affect
the inlet performance. Efforts are underway to study the effect of wind speed
on size cutoff, and operators should check latest information on wind speed
dependence and inlet design.
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SAMPLER CONTROLS
VIRTUAL IMPACTOR
FILTER TRAY
FLOW SYSTEM
Figure 3. Beckman Dichotomous Sampler with Front Cover Removed Showing Major
Subassemblies
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VIRTUAL IMPACTOR
The sampled particles smaller than 15 (jm pass through an inlet tube,
which serves to straighten the flow, and then into the virtual impactor, which
is shown in Figure 4. The virtual impactor is the basis for the operation of
the dichotomous sampler and was designed by Loo et al(4). Particles entering
the impactor are accelerated through a nozzle, and enter the fractionation
zone. Because of their greater inertia, particles larger than 2.5 pm are
drawn directly into the collection nozzle and then deposited onto a filter.
The large particles do not follow the flow stream and "impact" into the low
flow region of the collection tube. Because of the geometry of the
acceleration nozzle, only about 10% of the total flow which enters the
impactor goes through the collection nozzle. The remaining 90% of the flow,
which contains the smaller particles (fine fraction), passes around the nozzle
and through a tube to a separate filter.
The cut point between fine and coarse fractions depends on flow rates ,
the diameters of the acceleration and collection nozzles, and the distance
between nozzles. Figure 5 shows collection efficiencies for the coarse
particle fraction. The lower 50% cutpoint for the coarse fraction occurs at
2.5 urn. Losses of particles on the walls of the impactor are measured to be
less than 10% at the cut point, which represents very good performance for a
single stage virtual impactor (4).
SAMPLING FLOW SYSTEM
Atmospheric particulates are sampled through the inlet at at rate of 1
cubic meter per hour, or 16.7 liters per minute. The sample flow entering the
impactor is split into two separate flow systems (see Figure 6). About 10% of
the sample goes through the collection nozzle and onto the coarse filter at a
rate of 1.7 liters per minute. From the filter, the air sample is carried
into a ballast volume which smooths the flow for the WISA vibrator pump.
Control and flow indication in the coarse flow system is provided by a needle
valve and rotameter.
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AIR FLOW
SMALL PARTICLE
TRAJECTORY
LARGE PARTICLE
TRAJECTORY
ACCELERATION NOZZLE
FRACTIONATION ZONE
COLLECTION NOZZLE
TO COARSE
FRACTION FILTER
TO FINE
FRACTION FILTER
Figure 4. Sketch of Virtual Impactor Showing Separation of Coarse and
Fine Flows
100
80
•60
40
20
COLLECTION EFFICIENCY
23 5 7 10
AERODYNAMIC PARTICLE DIAMETER, i
20
30
Figure 5. Graphic Representation of Virtual Impactor Collection
Efficiency vs. Particle Size for a Design Cutoff of 2.5 ym
10
-------
The smaller sized finer particle flow passes around the collection nozzle
and is collected on a second filter at a flow rate of 15.0 liters per minute.
After the filter, air goes through a flow control device which provides
regulated flow in conjunction with a precision needle valve. The flow setting
of 15 £pm is initially set by the needle valve and rotameter. The needle
valve then functions as a fixed flow control orifice. A dual diaphram pump
provides the vacuum necessary to induce flow through the system.
A differential pressure switch acts as a safety release in case of filter
overload. The switch is connected across the needle valve to sense the
loading on the fine filter (indicated as "PS3" in Figure 6). If resistance
across the fine filter rises enough to cause a 5% decrease in regulated flow,
then the next pair of filters is automatically inserted. This is likely if an
unusually high atmospheric particulate loading exists, such as in an episode.
The flow controller maintains a constant flow rate until the fine filter
loading causes a pressure drop of about 20 cm (8 in) Hg. Experience has
indicated that the filters are effectively fully loaded at that point (2). It
should be noted that earlier production models were equipped with two
additional pressure switches to detect torn or missing filters ("PS1" and
"PS2" in Figure 6). Later models of the instruments do not have these
switches.
Accurate flow control is extremely important in the dichotomous sampler,
as the pressure drop across Teflon filters can increase rapidly as they
collect particles. Maintaining the 16.7 £pm flow through the system is
essential to maintain the particle size cutoff specifications of the inlet and
virtual impactor.
FILTERS
The dichotomous sampler uses Teflon filters mounted in 5 cm x 5 cm frames
with a 29 urn deposit dia., shown in Figure 7. Filters are available in two
types, one in which the filters are bonded to the frames, and a second in
which the filter is removable to facilitate subsequent analyses. The filters
11
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PRESSURE
SWITCH
FRACTIONATING
INLET
THOMAS DUAL
DIAPHRAGM PUMP
DIFFERENTIAL
PRESSURE SWITCH
TOTAL
SYSTEM
FLOW - 16.7
LITERS/M1N
RECOMMENDED
INSTALLATION
OF VACUUM GAUGE
HISA PUMP
NEEDLE
VALVE
Figure 6. Sketch of Dichotomous Sampler Flow System Showing Fine and Coarse Flow Paths.
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FILTER TRAY
FILTER TRAY PREPARED
FOR SHIPMENT
FILTER HOLDER
FILTER INDEXING
GUIDE
Figure 7. Filter Tray Showing Filter Holders and Indexing Guide
13
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have a 1 urn pore size, and are preferred for their low initial pressure drop
and minimal water retention. Also the Teflon material has negligible particle
penetration and efficiently collects particles as small as 0.04 pm. The low
2
weight per unit area (1 mg/cm ) and chemical inertness make the filters
suitable for XRF, p-ray densitometry and wet chemical analysis.
The filter frames are held in trays having 36 slots each. Two trays, one
for the fine fraction and one for the coarse fraction, are inserted into the
sample change mechanism, as shown in Figure 8. The sampler can be programmed
to collect automatically up to 36 pairs of filters, but the first pair must be
held blank to serve as a control. Pairs of filters are advanced by the sample
changer when the preselected delay period between samples has been completed
or when the flow differential pressure switch has been activated because of
heavy loading on one of the filters.
Each filter is weighed and labeled with an identification number prior to
shipment of the filter trays to the sampling site. It is extremely important
that complete records be maintained of the samples used and of sampler
operation. A suggested data collection and record keeping procedure is
provided in Section 7; however, the operator should make sure that the forms
and instructions appropriate to the particular sampling program are on hand.
FILTER CHANGE MECHANISM
The sample changer subsystem consists of a filter shuttle drive, a tray
indexer and a filter seal mechanism, as shown in Figure 9. These three
mechanisms are mechanically independent, but all are controlled by the
instrument microprocessor. The filter shuttle moves back and forth, pushing
the clean filters into position to collect a sample and returning the used
filters to the tray. This shuttle is attached to a simple eccentric
cam-actuated rotating assembly which moves the shuttle in and out of filter
trays. Feedback for the position of the rotating assembly is provided by two
mechanical limit switches actuated by a pin on the assembly.
14
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CARRIAGE
RELEASE
KNOB
FILTER
SHUTTLE
FRONT OF INSTRUMENT
FINE PARTICLE
FILTER
COARSE PARTICLE
FILTER
Figure 8. Interior of Sampler Showing Filter Change Mechanism, Filter
Trays Inserted and Filter Pair in Place (Virtual Impactor has
been removed)
15
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FILTER TRAYS
RECIPROCATING
SHUTTLE
SHUTTLE DRIVE
ECCENTRIC
SHUTTLE DRIVE
MOTOR
CARRIAGE RELEASE KNOB
OPTICAL DETENT
FILTER SEAL
ECCENTRIC
JACKSCREW
FILTER SEAL
MOTOR
MOVABLE CLAMPING
PLATE
OPTICAL DETENT
PICKUP HEAD
TRAY DRIVE MOTOR
Figure 9. Sketch of Filter Change Mechanism
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The filter shuttle drive only operates in the horizontal direction.
Vertical movement of the filter trays is controlled by the tray index assembly
so that fresh pairs of filters can be loaded in proper sequence by the filter
shuttle mechanism. Vertical motion is provided by a jack-screw which engages
the tray index carriage. A knob at the top of the carriage can be turned to
disengage the carriage from the jackscrew to allow initial positioning of the
trays. Unlike the other two mechanisms in the sample changer, the tray index
assembly has multiple rest positions. Position feedback for this assembly
therefore is provided by a multiposition optical limit switch rather than
simple mechanical limit switches. In Figure 9 the notched optical detent and
pickup head are shown on the front of the trays for clarity; however,the
actual location is behind the tray, since access is not normally required (2).
The filter seal mechanism clamps and seals the filter slides into the
pneumatic system once the shuttle drive has pushed them into place for
sampling. It is operated in sequence with the other mechanisms under
microprocessor control. Vertical motion is applied to the filter clamping
tubes by a simple eccentric cam. Position feedback is provided through limit
switches actuated by two eccentrics on the end of the clamp shaft (2).
Figure 8 shows the filter change mechanism with filters in place.
TEMPERATURE CONTROL SYSTEM
Sampler housing is internally heated to +33°C (91°F) using a
fixed-set-point, 250-watt, proportional temperature controller. This
controller will maintain the housing at the control temperature through
variations in ambient air temperature from +30°C to -40°C. If ambient
temperatures rise above the controller set point (+33°C), the temperature
inside the housing will rise accordingly.
Besides the proportional temperature controller, several other thermal
switches are included in the system to help control the internal temperature
and to protect circuitry and components:
17
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Where ambient temperatures are very high, a high-temperature thermal
switch will actuate at +48°C (+118°F) to energize the intake blower
fan. The fan directs air flow over the microprocessor circuit board
and associated electronics to prevent extended operation at highly
elevated temperatures. This thermal switch is located inside the
electronics housing assembly on the filter changing assembly (2).
A low-temperature thermal switch disconnects both the battery power
and the +5 Vdc regulated power to the microprocessor when internal
housing temperatures go below 0°C. The instrument must warm up to
+4°C (39°F) before power is restored. This thermal switch is located
within the electronics housing on the interconnect circuit board
(2).
A third thermal switch, mounted on the underside of the instrument
base plate, closes at -7°C. This connects a second 250-watt heating
element to the controller, to increase internal heating for
operation in extremely low ambient temperatures (2).
Figure 10 shows the thermal switch actuating temperatures and the control
ranges for the Sampler. Note that a neon indicator lamp, which is visible on
the front side of the power supply, is connected across the heater elements to
indicate when the heaters are fully on (lamp on continuously), in proportional
control (lamp flashing), and off (lamp off).
SAMPLER CONTROL SYSTEM
One of the most unique features of the Beckman dichotomous sampler is its
Microprocessor Control System, shown in Figure 11. The microprocessor
generates a sequence of timed comands which control the visual display,
lights, keyboard, printer, motors, and pumps. The total sampler operation is
controlled by an 8-bit microprocessor-based system using an 8085 Central
Processing Unit (CPU). Control programs are stored in 4K of Read-Only memory.
18
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TEMPERATURE
CONTROLLER
INTAKE FAN
MAX HEATER
POWER
BATTERY
AND
tP POWER
33°C
FULL ON
PROP
OFF
250 W
500W
-7-C
QN
OFF
-7*C +4°C (Ta)
-40°C
Tr INTERNAL TEMPERATURE
T - AMBIENT TEMPERATURE
A
OFF
ON
+48"C
Figure 10. Diagram Showing Temperature Control Ranges and Switch-
Actuating Temperatures
KEYPAD
DDDD
DDDD
DDDD
DDDD
POWER
SUPPLY
BATTERY
BACK-UP
DISPLAY
LIGHTS
1
— o o —
— o o —
— 00
— o o —
— o o —
— o o
o o
f
MICRO-
PROCESSOR
|
SAMPLE CHANGER
FILTER
SHUTTLE
FILTER
SEAL
t
VERTICAL
TRAY
t
MANUAL SWITCHES
^
PRINTER
REAL TIME
CLOCK
PRESSURE
SWITCH
PUMPS
Figure 11. Simplified Electronic Control System Diagram
19
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The microprocessor board power requires a single +5Vdc supply, with battery
back-up (2).
Sampler operation is programmed by the key pad. Current data and time,
sample start time and date, number of samples, and time between samples are
entered, following the sequence indicated by the display panel lights. The
printer provides a record of sample parameters. Manual switches are included
to actuate the filter shuttle, filter seal, vertical tray index mechanisms and
the sampler pumps.
A more detailed description of the key pad display lights and manual
switch functions is included in Section 6, Operating Procedures.
20
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SECTION 3
CONSIDERATIONS IN SITE SELECTION
SITING CRITERIA
Selection of the sampling site and sampler location is dependent on the
intended use of the collected data, as well as several other considerations.
This section provides criteria and a suggested methodology for site selection.
The information is based on the recommendations of the EPA's Standing Air
Monitoring Work Group (SAMWG) and the final regulations on ambient air quality
monitoring (5). Appendices D and E of reference (4) discuss network design and
sampling probe siting criteria, respectively, and should be reviewed prior to
establishing the monitoring site. Another valuable reference is the report of
Ludwig, Kealoha and Shelar (6).
A dichotomous sampling program can serve a variety of objectives. The
dichotomous sampler gives information on the coarse and fine fraction of
suspended atmospheric aerosols below 15 urn in diameter. These fractions may
have similar or different sources. These sources may be local or distant.
One size fraction may reflect variations in local sources and dispersion
conditions while the other fraction does not. Therefore, in choosing a site
consideration must be given to factors that might bias measurements and
compromise sampling objectives.
In siting dichotomous samplers two general categories of impacts should
be kept in mind. Meteorological (mesoscale and microscale) effects and local
source configurations might influence fine and coarse particle levels.
21
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Meteorological factors on the local scale are the altered wind flow
patterns or mixing conditions by topographic features. Tables 1 and 2 are
included to highlight these considerations.
TABLE 1. Topographic and Meteorological Influences on Local Dispersion
Topographic Features
Effects
1. Elevated regions
2. Deep valleys
3. Undulating regions
4. Regions of tree cover
5. Bodies of water
a. Increased wind speed (and increased
ventilation) over hill tops.
b. Occasional impacting of elevated plumes
on ground level.
a. Channeling of wind flow along the valley
axis, resulting in higher average
concentrations in the valley.
b. Development of stable, drainage winds
during calm, nighttime conditions,
resulting in higher concentrations along
the valley floor.
a. Increased atmospheric turbulence near the
ground level during time of moderate or
strong winds. This results in lower
pollutant concentrations at locations
near sources.
b. Accumulation of pollutants in low spots
during calm, nighttime conditions (i.e.,
localized drainage wind conditions).
a. Enhanced turbulence near the ground
during moderate or strong winds,
resulting in lower concentrations for
locations near sources.
b. In fully covered regions, blockage of
elevated plumes, resulting in lower
concentrations at ground level.
a. Increased moisture content in the local
atmosphere, favoring fog formation at
low-lying spots, and affecting the
removal rate of SOp and other pollutants
from the atmosphere.
b. For larger bodies of water, formation of
local circulation (lake and sea breezes)
which can cause ground level fumigation
on the landward size of sources, during
sunny daytime conditions.
22
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TABLE 2. Source Configuration and its Influence on Dichotomous Sampling
Source
Effects
1. Unpaved roads, sanded or salted
open fields, stockpiles
sand, etc.
2. Heavy traffic on nearby road
3. Overhanging trees -- beneath
densely forested canopy
4. Rooftops, gravel roofs
5. Building wakes
Resuspension of surface dust roads,
contributing to coarse fraction.
Resuspension of coarse particles, local
source of fine particles high in Pb,
Br.
Some possible filtration of coarse
particles; also production of pollens.
Building exhaust vents, local chimney
emissions. Possible resuspension of
roof material.
Possible influence of wake capture of
building emissions.
INSTALLATION REQUIREMENTS FOR THE DICHOTOMOUS SAMPLER
Installation requirements for the dichotomous sampler are minimal. It is
designed to operate outdoors, through a range of ambient temperatures of -40°
to 122°F. The internal heating blower system essentially eliminates the need
for external temperature or humidity control. Although the instrument is
housed in a weather-tight shelter, it may also be placed indoors. This will
facilitate calibration and maintenance and protect the filters during
handling. Indoor installations require the availability of a level, flat,
rigid surface to support the four legs of the shelter, and some modifications
to the sampler inlet standpipe. Indoor installations also require access to
the ambient air directly above the sampler to allow placement of a straight
pipe to the fractionating inlet. Provisions should be made to provide enough
clearance above the sampler to allow removal of the shelter which must be
lifted up and over the instrument.
23
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The instrument weighs less than 200 pounds and can be lifted by two
persons using the grip handles on the sides and rear and the upper lip of the
front door of the shelter. It can be plugged into any grounded 115 Vac
electrical outlet and requires no further utility connections.
As with the placement of other particulate samplers, the inlet for the
dichotomous sampler must be located 2 to 15 meters above the ground (5). Two
meters is considered minimum height necessary to avoid entrainment from dusty
surfaces; the 15 meter upper limit is essentially a compromise between the
desire to have instruments that are most representative of population
exposures and the practical considerations of site security and accessibility.
Further, the inlet should not be within two meters of walls or other
obstructions or within 20 meters of large trees which often provide surfaces
for particle deposition and restrict airflow.
Since the dichotomous sampler may be co-located with hi-vol samplers it
is recommended that the dichotomous inlet be placed so that it is not within
two meters of and at least 0.5 meters above the hi-vol. This will reduce the
collection of copper and carbon particles from the hi-vol motor. If possible,
exhaust from the hi-vols should be ducted away from the dichotomous sampler by
using a large flexible hose or similar device attached to the bottom of the
hi-vol motor housing.
24
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SECTION 4
INSTALLATION PROCEDURES
DELIVERY AND UNPACKING
Although the sampler is inspected and packed to protect it during
shipment, there is always the possibility of damage. Carefully inspect the
shipping package for any external signs of damage, note this information on
the delivery receipt, and have the delivery person sign all copies of the
receipt before leaving. Unpack the instrument and check each item against the
packing slip to make sure everything has been included in the shipment.
As soon as possible, the sampler should be assembled and checked out to
verify that there is no internal damage. Experience has shown that the filter
change mechanism is more likely to be damaged in transit than other
assemblies. Also, the shelter housing legs may be bent or broken, and the
plastic caps used to plug the former location of two pressure switches in the
flow lines (see Figure 20) may become dislodged or lost. These caps must be
in place before sampling.
If there is any indication of either internal or external loss or damage
to the sampler, the shippping company and manufacturer's sales representative
should be contacted immediately before any further use of the sampler.
SAMPLER INSTALLATION
Before starting the actual installation, make sure the site location and
instrument placement meet the criteria and requirements described in Section 3
of this report.
25
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Outdoor Installation
The Beckman dichotomous sampler requires no special installation
procedures if it is to be used outdoors. The instrument should be placed on a
firm, level supporting surface and securely anchored. High wind speeds in
excess of 50 mph can cause the sampler to tip over. Be sure to provide
several inches of clearance below the sampler housing, as the interior air
circulation ports are loacted in the base plate. The fractionating inlet is
attached to a sampling standpipe, which is inserted through the top of the
sampler housing. The standpipe should be lined up and firmly butted against
the impactor inlet. Use a flexible sleeve or a 2-inch length of IV I.D.
tygon tubing as shown in Figure 12 to connect the standpipe and the impactor.
The clamp located on the underside of the shelter housing top should then be
tightened to hold the standpipe in place during sampling. There should not be
any space between the standpipe and impactor in order to maintain a smooth air
flow into the impactor. Once the standpipe and inlet are installed, the
sampler may be plugged into a grounded 115 VAC electrical outlet, it is then
ready for checkout and operation.
Indoor Installations
Although the dichotomous sampler is designed for use outdoors, it can be
located inside a building, instrument shelter or trailer. This type
installation requires minor modifications of the instrument but may be
preferable in some sampling situations. If an indoor installation is
selected, the fractionating inlet must be located in the ambient air directly
above the impactor. This requires an extension to the inlet standpipe and a
fixed supporting sleeve through which to raise and lower the standpipe. A
typical installation is shown in Figure 13.
The standpipe extension should be made of rigid piping with a nominal 1"
inside diameter and Ik" to 1 3/8" nominal outside diameter. The standpipe and
extension together should be long enough so that the sampler inlet will be at
least 2 meters above the sampling station roof when the unit is in operation.
26
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TRAY INDEXING
TAPE
STANDPIPE CONNECTOR
(TYGON TUBING")
IMPACTOR
ASSEMBLY
IMPACTOR ASSEMBLY
SUPPORT BLOCKS
Figure 12.
Interior of Sampler Showing Filter Tray and Virtual Impactor
Installed. (Note section of Tygon tubing at top of Impactor
for connecting to standpipe; also note tray indexing on side
of filter tray.)
27
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FRACTIONATING INLET
STANDPIPE
STANDPIPE EXTENSION
SUPPORTING SLEEVE
SAMPLING STATION ROOF
Figure 13. Standpipe Extension and Supporting Sleeve as
Required for Indoor Sampler Installations
28
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The extension may be attached to the standpipe by using a section of IV tygon
tubing or other suitable material, clamped to the standpipe and the extension.
Be sure that the extension and standpipe are firmly butted together so that no
flow irregularities are induced.
Material selected for the extension tubing is a concern because of
potential wall losses along the additional length. Stainless steel tubing
will reduce this potential, but may not be practical or readily available. If
PVC pipe is used, large wall losses can be expected. Aluminum pipe is
satisfactory if great care is taken to prevent aluminum (from the pipe walls
and especially pipe ends) from falling into the sampling stream.
Since the standpipe must be free to be raised and lowered to the
impactor, it cannot be fixed to the roof of the sampling station or trailer.
A rigid sleeve which is firmly attached to the roof must be provided (see
Figure 13). Make the sleeve out of PVC piping to minimize the possibility of
metal particles becoming dislodged as the standpipe is moved. The inside
diameter should be sufficient to allow free movement of the standpipe and
extension once they are joined together. The supporting pipe should be tall
enough so that the inlet rests on the top of the pipe during sampling. The
pipe may be fixed to the roof by metal brackets such as in Figure 13 or by guy
wires.
Once the standpipe extension and supporting sleeve are installed, the
standpipe should be lowered onto the impactor and connected by use of flexible
sleeve or section of Ik" I.D. tygon tubing, as was shown in Figure 12. The
clamp located on the underside of the sampler housing top should be tightened
to hold the standpipe in place during sampling. Be sure that there is no
space between the standpipe and impactor in order to maintain smooth air flow
into the impactor. Once the standpipe is attached, the sampler can be plugged
into a grounded 115 VAC electrical outlet and is then ready for checkout and
operation.
29
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For the convenience of the operator, it is suggested that a muffler be
installed on the pump exhaust to reduce noise level in the sampling building.
Several types of mufflers are available. Appendix I describes one of these
that has proven to be effective in field tests.
Note: It is strongly recommended that a worm drive circulator clamp be
used to hold the standpipe and impactor inlet together. The clamp should be
placed around the two inch tygon tubing section which is used to join the
inlet and impactor.
Description and sources for accessories and materials discussed in this
report are provided in Appendix I.
CAUTION
Always turn the POWER switch off before disconnecting the power cord.
Otherwise, the battery backup system will be activated; after 30 minutes, the
batteries will be completed discharged.
30
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SECTION 5
CHECKOUT AND CALIBRATION
Since performance of the virtual impactor is highly dependent on the flow
rate through the sampler, it is critical that precise flow calibration and
accurate flow control be accomplished. Thus, it is essential that the system
be carefully checked out and calibrated prior to initial sampling and at
regular intervals thereafter as suggested in Section 8 of this report. This
section provides instructions and recommendations for initial checkout of the
sampler. It also includes procedures for calibration of the fine and coarse
flow rates, and for total flow system checks. To perform the tests and
calibrations described here, the operator must be familiar with the operating
procedures described in Section 6.
INSTRUCTIONS FOR SAMPLER CHECKOUT
1. Once the instrument is unpacked and set up, an operation check of the
printer and system controls should be performed to verify that no damage
has occured to the internal mechanisms. The operator should complete
Items 2 through 11 of the operating instructions in Section 6, and check
carefully that the light sequence, printer output, clock and other
controls are working properly. It is not necessary to unpack and load
the filter trays for this checkout step.
2. The virtual impactor assembly should be removed and cleaned in accordance
with the instructions in Section 8. Once the impactor is reassembled and
installed, the impactor inlet should be covered with a #7*5 or #8 rubber
stopper, aluminum foil, or a similar device so that dirt and other
31
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foreign objects will not inadvertently enter the impactor. NOTE: The
inlet should always be covered when the sampling standpipe is removed.
3. It is strongly recommended that a vacuum type pressure gauge (see parts
list in Appendix I) be installed in the flow sytem, located as shown in
Figure 20. To install, locate the tee type fitting which is at the lower
right of the fine flow rotameter. Note that one part of the tee is
plugged. Remove the plug and install the vacuum gauge. Be sure that no
"stringy" pieces of Teflon tape are left in the tee fitting after the
plug has been removed. Position the gauge dial so that it can be read
easily at the same time as the rotameters.
4. Since the flow checks and calibrations described below will be performed
with a pair of filters (not the first set, #1) in place, each filter tray
should be checked for damaged filters. Early models of the Beckman
sampler contained pressure switches to sense torn or missing filters.
However, later production models do not have this feature and each filter
must be checked prior to loading of the trays. NOTE: The filters should
be handled carefully using the filter frames. The Teflon collecting
surface should never be handled directly.
5. To assist in indexing the filters in the trays, it is suggested that a
piece of tape be placed along the front edge of the filter tray, and
markings located on the tape to correspond with the filter numbers 1-36.
Figure 12 shows a typical installation.
6. All flow checks and calibrations should be performed after the sampler
door has been closed and top unit turned on for at least 2 hours. This
will allow the instrument to reach its normal operating temperature. The
power switch should be turned on; however, it is not necessary to turn
the pumps on. Also, the unit should be run for at least 15 minutes with
filters in the sampling position and the front access door closed.
32
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7. After the instrument is warmed up, the filter seal system must be checked
for leaks. Insert a pair of filters (not the first filter set) and close
the filter seal mechanism using the manual switch. Turn on the pumps and
plug the flow through the virtual impactor by either inserting the rubber
stopper or by inserting the calibration adaptor described in Appendix I
and closing the adaptor valve. Flow through both the fine and coarse
flowmeters should drop to zero. If any flow is indicated, the filter
seal mechanism should be checked. The limit switches on the filter seal
mechanism and the seal tube height can be adjusted following the
instructions provided in Section 6.2.3 and 6.2.4 of the manufacturer's
manual (2).
Another possible source of flow leaks is in the blocks that support the
impactor assembly (see Figure 12). In later production models these
supports were machined down 0.03 in. to provide a tighter seal around the
filters. Operators of early models of the instrument should consider
retrofitting their samplers with the modified support blocks (after
contacting the factory) if a flow leak is indicated.
If the seal mechanism is adjusted properly and there are no loose or
damaged fittings or tubing but leaks are still present, the
manufacturer's service department should be contacted for further
troubleshooting. If no leaks are indicated but the flow cannot be
adjusted to obtain 15 liters per minute through the fine flowmeter, there
may be a problem with the flow controller or the pump, and again the
manufacturer should be contacted for further instructions.
8. Once the system has been checked for flow leaks and adjusted, if
necessary, calibration of the fine and coarse flow system should be
accomplished using one of the methods described below. The flow
measuring devices selected for the calibration must be suitably
calibrated themselves (e.g., standard NBS bubble meter for low flow, and
lab-type calibrated spirometer for high flow measurement equipment)
before being used to calibrate the dichotomous sampler.
33
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NOTE: Since flow measurements are highly sensitive to temperature
conditions, equipment used in calibrations and the sampler should be at
comparable temperatures during calibration. Allow equipment to
equilibrate in the sampler operating environment for about two hours
prior to proceeding with the calibrations.
INSTRUMENT CALIBRATIONS
Instructions are provided below for two methods of fine and coarse flow
calibration for the dichotomous sampler: The first uses ball-in-tube
rotameters, and the second uses a Singer Model DTM-115-3 dry test meter. For
the rotameter calibration system, flow calibrations are to be made at a point
above the filters (referred to as "at inlet") and a point below the filters
("at base"). This will assist in detection of leaks in the filter sealing
mechanism. It j_s important to note that leaks HI the filter seal area cannot
be detected by_ the sampler's built-in flowmeters. For the dry test meter
method, flow calibration is made only at the inlet because it is not practical
to perform flow checks both above and below the filters. If the flow check and
inlet flow calibration are done according to the instructions for the Singer
meter, then adequate leak detection will have been accomplished.
Descriptions, specifications, and supply sources for equipment used in
these procedures are presented in Appendix I.
CALIBRATIONS USING ROTAMETERS
It is recommended that Types 603 and 604 rotameters as described in
Appendix I be used for calibrations. As with all rotameters, they must be
corrected to temperature and pressure conditions at the sampling site. This
is most important when the rotameters are being used outside in cold weather
and/or high altitudes. For the 603 and 604 rotameters, pressure and
temperature correction tables are provided in Appendix II; if other flow
meters are used, see that manufacturer's recommended procedures.
34
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The operator is cautioned to review Item Number 6 under "Instructions for
Sampler Checkout" to ensure the instrument is adequately warmed up prior to
calibration. Also, the instrument must be checked for leaks in accordance
with Item 7 of the checkout instructions before proceeding.
Caution: To avoid possible damage to the pumps do not operate the sampler for
more than 20 minutes with the valves closed.
Fine Flow Calibration (at Base)
1. Attach the 604 rotameter to the polyethylene vacuum tube at the base of
the fine flow tube on the side of the filter change mechanism closest to
the front access door, as shown in Figure 14. This is accomplished by
loosening the Swagelock fitting at the 90° elbow, removing the tube from
the elbow, and attaching it to the 3/8" adaptor fitting (described in
Appendix I). The adaptor is then inserted into the heavy walled V
vacuum tubing, and the tubing is attached to the 604 rotameter.
2. Once the tubing has been attached, the rotameter leveled, and the
operator is in a position to view easily both the 604 and fine flow
rotameters, the sampler pumps should be turned on.
3. Adjust the fine flow control valve (see Figure 20) to obtain air flow of
15 jfcpm on the 604 rotameter usiing the calibration curve provided with
the 604 meter. Allow the system to run at this flow rate for 5 minutes.
4. Record the observed flow readings of both the 604 and fine flow
rotameters, and of the vacuum gauge.
5. Using the fine flow control valve, adjust the flow through the 604
rotameter to obtain readings for two flow rates above 15 £pm and two
below. Record indicated flow readings for both the 604 and the fine flow
rotameters for each point. Also record the vacuum gauge reading at each
point. Using the 604 rotameter calibration curve, determine true air
35
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604 ROTAMETER
1/4" VACUUM TUSE
FINE FLOW ROTAMETER
FILTER OVERLOAD
ADJUSTMENT SCREW
Figure 14. Typical Installation for Fine Flow Calibration at Base
Using 604 Rotameter
36
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flow for each point, and plot the indicated versus actual flows. Figure
17(a) shows a sample form that will simplify data recording and plotting.
Separate forms are necessary for the fine and the coarse flow
calibrations.
6. Draw the calibration curve and determine the proper fine flow rotameter
set point to obtain an actual flow rate of 15 £pm.
7. Return the 3/8" polyethylene tube to the 90° elbow Swagelock fitting and
tighten securely.
Fine Flow Calibration (at Inlet)
1. Attach the 604 rotameter to the valve of the inlet adaptor tube
(described in Appendix I) with the heavy wall vacuum tubing, making sure
that the valve is fully open (counter-clockwise), as shown in Figure 15.
2. Insert and seal a clean set of filter (not filter set #1) into the filter
mechanism.
3. Turn the coarse flow control valve (Figure 21) off (clockwise) so that
only fine flow is being drawn through the inlet.
4. Adjust the fine flow rotameter to read the 15 £pm set point which was
determined at the base calibraiton. If the 604 rotameter does not give
the same reading as it did during the base calibration, the seal
mechanism is suspect of a leak and may need adjustment [see Sec. 6.2.3-4
of Beckman Manual (2)].
5. If the same reading is found, proceed to adjust the fine flow valve to
obtain two points above 15 £pm and two points below as before. Record
these data including the vacuum gauge reading on the fine flow
calibration form in the "At Inlet" section, Figure 17(a).
37
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ADAPTOR FLOW
CONTROL VALVE
CALIBRATION ADAPTOR
ROTAMETER
Figure
15.
Fine
Flow Calibration at
Adaptor.
38
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603 ROTAMETER
TYGON VACUUM TUBE
COARSE FLOW ROTAMETER
Figure 16. Typical Installation for Coarse Flow Calibration at Base
Using 603 Rotameter
39
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6. Again plot the points which should be similar to the "At Base" curve.
From both curves determine the proper set point.
Coarse Flow Calibration (at Base)
1. Attach the 603 rotameter to the "Tygon type" vacuum tube at the base of
the coarse flow tube, the side of the filter change mechanism farthest
from the access door as shown in Figure 16. This is accomplished by
pulling the Tygon tubing off the nipple at the 90° elbow and attaching it
to the adaptor nipple (See Appendix I for adaptor description). This
adaptor is then attached to the heavy wall vacuum tubing and the 603
rotameter. Be sure that the Tygon tubing is not pinched or bent sharply.
2. Once the tubing has been attached and the operator is in a comfortable
position to read both the 603 rotameter and the coarse flow rotameter,
the sampler's pumps should be turned on.
3. Adjust the coarse flow valve to obtain a reading of 1.7 2pm on the 603
rotameter. Allow the pump to run for 5 minutes.
4. Adjust the valve to obtain readings for two points above 1.7 £pm and two
points below. Record this data on the coarse flow dichotomous sampler
calibration form Figure 17(b) in the "At Base" section.
5. Plot the curve and determine the proper set point to obtain a flow rate
of 1.7 £pm.
6. Return the "Tygon type" tubing to the 90° elbow and check to see that
both ends of the tube are firmly attached.
40
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FINE FLOW DICHOTOHOUS SAMPLER CALIBRATION
Site:
Date:
DICHOT. CALIBRATOR
TYPE
Ser. No. Ser. No. '
1 — At
Last Calib.... Last Calib. Bas
Current Temp, Temp.
Current Press. Atm. Press.
By
Low flow cut out switch set Ij^i
at 1pm
Remarks:
_i I
i ~ ~ i i :: 1 1 ::...:: - - T
r. z. - - ...-4
t ~ : . . _ . 4
i _i
,
is • • • : ".'.".'.'.'.'. !; r r "
L tl L [
I ft
u L 1. L
r [Li
L! t i
r r 1
17 L L L
p .£" Jl ' L 1 L I
"• r" "L t- t t t
rH L II I
1 J I
1 1 J 1
I I
5 1 t
5 . _ - ~ ± - -i _j -"i ~| - •• r
CM 16 ~*~ "h
j
fc __._._-_ .JJ Ii- - ... - . ..]....
< i : i : : i : 1 1 1 1 z 1 1 " 1 1 1 : i : : i j; " * : :
± : : : :: :. ._...._ T
o T " T~
4
t* -m F jT
T
I
i : : : 1 1 • :
: i i . . ; t i ~ : "
T
: in j — • • r
- • • • j
;;:••••• 3 •
u :: ; ;. 1 1 :i i : i ii 1 1 ii i Ii
~
13 " "
j j .. i . . i
j d . J .1
j Ij ~l
j "1 ^
J -J L
12 (35) (40)
12 13 14 15
Dichot. 604 Rotameter Actual VAC.
Rotameter Indicated lorn ins.
nd lea ted
E
= t
. . - -i- . . 4- •'•
-»
. . J | " "
- h h F
t L L t L—
u. L EZ t [Z
I " r ' L L.
1 1 1 [
1 [- -t I
r Li
1 i
I j~*
i i j~
I r"
T r
t { - ' * ' t " ? - ~
T~
^T~
i
"^
I
i L
t "J "T -p - • -J- - - —
f«5) (50)
16 17 18
Observed Flow Meter Reading
Figure 17a. Suggested Fine Flow Calibration Form
41
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COARSE FLOW DICHOTOMOUS SAMPLER CALIBRATION Site:
Date:
DICHOT. CALIBRATOR
TYPE
Ser. No, »er. no.
Last. Calib. Last Calib. las
Curr. Temp. Tenp.
Current Press Attn. Press. i
Bv At
Inl
Remarks :
• : : i.. : }..
: _ i 4.
:: i. : ------- 4-
it
. : : ± . .
. . : ± : ....
. : : : ±
T
§i
. ±
1
t
. .1. ..... .
. 4- -• 4-1
, _ .1. . j .1
_L _,_ j~ 1 _ _ _
in -- L. . , a- T -
^ ~ " " il " IL |" " "
< " - r • • P P " t p i" "-" .
"""i " " b b ' " " p - • - -
o "t t t " h
* : - : : ± J ± _ t
1.7 • : : ' :
j . . . ......... —
]
- - - -_\
.----..
- • - - i-t-i- - - -
IS . - ...--..-_...-.-..
"
1 t" 1 I
31 . J~ J-
: . . ± : ± 1
i . ± i
1 r
I -L
i ^ _j_
i-4 (14) (15) (16) (17)
1.4 1.5 1-6^ ,1-7
Dichot. 603 Rotameter Actual
Rotameter Indicated 1pm
Indicated
e
et
. . . .t - i -
L
T " " T ~ ~
. ....:.. ± : : : ± : ~
r
L . - ... ± . . L .
. . .. ± ± . . r _
. ... .L . . ± . J- -
...L ±.±__
. . . L . -L . 1 - p
• _1_ f" |
I L L
_r~ p
4 ' £ n
i
I * ____,
....:., -±-
til - - -- .-
1 -1 1.-.: L:..:L, •>: ; L ::::
i r- - p ----
• i j i
[ L. J
[ t-
_i r n
L E- J
I t_ n
1 \- -J
i I L _ T
J J i
: - tl - - -
F :::::::::
I \-
j! iill |! 111
T :: I : i \"~
-- - "
U . - L ± . ..L
; . t ± . _ _t
j-'LJ' JL JlJI IE-_
(18) (19) (20)
1.8 1.9 2.0
Observed Flow Moter Reading
Figure 17b. Suggested Coarse Flow Calibration Form
42
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Coarse Flow Calibration (Inlet)
This procedure is similar to the fine flow rotameter (inlet) calibration.
1. Attach the 603 rotameter to the valve of the inlet adaptor tube with the
heavy wall vacuum tubing, making sure that the valve is fully open
(counter-clockwise).
2. Insert and seal a clean set of filters (not filter #1) into the filter
mechanism.
3. Turn the fine flow control valve (Figure 21) fully off (clockwise) so
that only coarse flow is being drawn through the inlet.
4. Adjust the coarse flow control valve to read the 1.7 £pm set point which
was determined at the base calibration. If the 603 rotameter does not
give the same reading as it did during the base calibration, the seal
mechanism is suspect of a leak and may need adjustment. (See Sec. 6.2.3-4
in Beckman's Manual).
5. If the same reading is found, proceed to adjust the valve to obtain two
points above 1.7 £pm and two points below as before. Record these data
on the fine flow calibration form in the "At Inlet" section [Figure
6. Again plot the points which should be similar to the "At Base" curve.
From both curves determine the proper set point.
Total Coarse/Fine Flow Check Using Only the 604 Rotameter at the Sampler Inlet
After the complete calibrations for both the fine flow and coarse flow
have been performed, a total flow check can be performed as follows:
43
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1. Attach the 604 rotameter to the inlet adaptor and then to the inlet of
the sampler as shown in Figure 15.
2. With a set of filters (not #1) clamped and sealed, and the pumps running,
adjust the fine and coarse rotameters to the set points determined by the
calibration.
3. Read the 604 rotameter and determine the total flow rate.
4. Next turn the coarse flow valve (fully clockwise) off. Observe the 604
rotameter reading as the fine flow. The difference between the total and
fine flow rotameter reading should be the coarse flow. This flow check
should be performed at the time of calibration and weekly, and the values
recorded.
CALIBRATIONS USING A DRY TEST METER
By using a Singer Model DTM-115-3 dry test meter connected at the sampler
inlet it is very easy to accurately set the fine and coarse flows. First, one
closes both the fine and coarse flow valves to verify that both valves seat
properly. Next, one opens the coarse flow valve and adjusts it so that the
Singer gauge and a stopwatch indicate an inlet flow rate of 1.67 £pm. Since
the fine flow is still shut, the inlet flow and coarse flow are the same. Now
adjust the fine flow to 15 £pm, but do not adjust the coarse flow. A correct
adjustment of the fine flow will result in a total inlet flow of 16.67 £pm as
indicated by the Singer gauge and stopwatch. A simple test for leaks can also
be made. The step-by-step instructions are as follows:
1. Connect the Singer dry test meter, as shown in Figure 18. Securely
tighten the ferrule to prevent leaks in the calibration system.
The following leak test is only appropriate when the aerosol sampler is
being set up or tested. During routine aerosol sampling, proceed
directly to step 3.
44
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SINGER DRY TEST METER
Figure 18. Typical Installation for Calibrations Using the Singer Dry Test
Meter
45
-------
2. a. While operating the sampler in the manual mode, insert a pair of
filters, engage the filter seal, and turn on the pumps.
b. Close the coarse particle flow valve on the dichotomous sampler.
c. Close the valve at the sampler inlet shown in Figure 18.
d. If there are no leaks, then the fine particle flow indicator on the
dichotomous sampler should drop to zero, and the gauge at the
sampler inlet (see Figure 18) should indicate a vacuum of at least
23 in. (58 cm) Hg.
e. If there appears to be a leak, first verify that the ferrule, valve,
etc, on the sampler inlet (see Figure 18) are not leaking. If the
leak is traced to the sampler itself, then the sampler requires
repair or adjustment.
3. Open the inlet valve shown in Figure 18. Close both fine and coarse
valves and verify that the flow is less than 0.1 £pm by observing that
the pointer on the Singer gauge changes by less than 0.1 liter in 60
seconds.
Caution: To avoid possible damage to pumps do not operate the sampler
for more than 20 min. with valve(s) closed.
4. Open the coarse particle flow valve, and as an initial approximation, set
the coarse flow to 1.7 £pm using the instrument's rotameter as a flow
indicator.
5. Measure the time for the Singer gauge pointer to change by at least 2
liters. For a coarse particle flow rate of 1.67 £pm, the time should be
72.0 seconds for 2 liters.
46
-------
6. If the measured time deviates from 72.0 seconds by more than 1.0 second,
adjust the coarse flow and measuring the time until a correct coarse
particle flow rate is obtained.
Verify the final value with an additional measurement
7. Now open the fine particle flow valve, and as an initial approximation,
set the flow to 15 £pm using the instruments fine rotameter as a flow
indicator.
8. Measure the time for the Singer gauge pointer to change 10 liters. Since
a total flow of 16.67 £pm should be flowing into the inlet (15 fine plus
1.67 coarse), the stopwatch time should read 36.0 seconds.
9. If the measured time deviates from 36.0 seconds by more than 0.4 seconds,
keep adjusting the fine flow and measuring the time until a correct total
flow is obtained.
Verify the final value with an additional measurement.
FILTER OVERLOAD SENSING SWITCH SETTING
The differential pressure switch which detects a filter overload
condition is controlled by using the adjustment screw shown in Figure 14. This
screw has been preset by the manufacturer and should not need resetting.
However, it is recommended that the pressure differential setting be checked
after completion of instrument calibration and prior to initiating a sampling
program. This check should also be performed as part of the six-month flow
audit described in Section 7, Quality Assurance.
Rotameter Method
To check the filter overload cutout setting, install the 604 rotameter
and flow calibration adaptor. Turn off the coarse flow completely. The
47
-------
instrument should be in the automatic mode. Begin to slowly turn the valve on
the adapter tube clockwise. This will restrict the flow to the dichotomous
sampler inlet. Note that as the flow is restricted, the sample will
automatically compensate by increasing the flow to the normal value. Closely
observe the 604 rotameter and note that at some point that the flow controller
no longer can compensate for the restriction and the total flow will begin to
decrease. Closely watch the 604 rotameter while continuing to restrict the
flow with the valve. Eventually the cutout switch will cause the sampler to
switch to another filter. It is at this cutoff point that the 604 rotameter
reading should be recorded. Reset the sampler in the automatic mode on the
same filter set. Repeat the above procedure a total of three times, recording
the 604 rotameter reading each time that the cutoff switch switches the
filters.
The filter overload pressure switch has been adjusted to actuate when the
fine flow decreases from 15 £/min to 14.25 £/min by filter loading. If the
check indicates a significant difference from this setting, the switch should
be adjusted.
To do this, rotate center adjusting screw on switch (Figure 14)
counter-clockwise to end of travel. Place instrument in automatic sampling
mode and set fine flow at 15 £/min. Restrict inlet flow using the calibration
flow adaptor valve shown in Figure 15 until flow drops to 14.25 £pm, and then
rotate the pressure switch adjusting screw clockwise until the filter pan is
switched. Back the screw out h turn from this point. Contact Beckman if this
method does not work.
Dry Test Meter Method
1. Perform steps 1 and 2 described in the above section, Calibrations Using
a Singer Dry Test Meter.
48
-------
2. Open the inlet flow valve shown in Figure 18.
3. Start sampling in the automatic mode.
4. Close the sampler's coarse particle flow valve.
5. Set the flow rate to 15 £pm as measured at the inlet. For this a 10
liters volume should pass through the dry test meter in 40 seconds.
To determine how the filter overload has been set previously, skip steps
6-8, and proceed directly to step 9 below.
6. Disable the filter overload switch by_rotating its adjustment screw fully
counter clockwise (see Figure 14) to end of travel.
7. Partially close the inlet flow rate restrictor so that the flow rate
decreases by 7%. At this point the dry test meter should require 43
seconds to pass 10 liters. Note the vacuum reading: it should indicate
about 5 to 10 in. (12 to 25 cm) Hg. This represents that the maximum
pressure drop across a filter that will cause a 7% decrease in flow rate.
If the vacuum is lower than the above range of values, then there is
probably a leak in the flow system.
8. Slowly rotate the filter overload adjustment screw clockwise until the
filters are caused to change.
9. Verify the setting of the filter overload adjustment screw. To do this
first open the inlet flow restrictor valve. Then slowly close it so that
the vacuum rises by about 1 in. (2.5 cm) Hg every 10 seconds. Verify
that the filters are caused to change when the vacuum has the same value
that was set in step 7 above.
49
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SECTION 6
OPERATING PROCEDURES
It is recommended that the operator become familiar with the principles
of operation (Section 2) and the instructions below before attempting to
operate the instrument.
In testing the sampler or in learning how to operate it, it is unwise to
use clean filters that have been preweighed for aerosol sampling. It is far
better to use a pair of trays that are used only for practice or testing.
SAMPLER HOUSING
The dichotomous sampler is housed in a weather resistant shelter that
must be firmly in place during sampling. The front door of the shelter may be
removed by turning the keylock clockwise and pulling the door out and down.
This will provide access to the keypad, printer, sample trays and flow
controls. Maintenance and troubleshooting may necessitate removal of the
entire shelter. To do this, raise and remove the inlet standpipe from the
shelter. Remove the metal screws around the base of the shelter, and lift the
shelter up until it clears the instrument.
CAUTION: Remember that whenever the standpipe has been removed, a No. 1\
or 8 rubber stopper or other suitable device must be inserted in the top of
the impactor to prevent dirt or foreign objects from entering.
50
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FRONT PANEL CONTROLS
The controls for programming and operating the sampler are located on the
front control panel (Figure 19). Their functions are described below:
1. POWER Switch: When button is depressed, power is applied to the
instrument; pushbutton is illuminated when power is on.
2. PAPER ADVANCE Switch: Paper in the printer is advanced when this switch
is depressed.
3. KEYPAD: The keypad controls all instrument functions for programming and
operation.
4. STATUS Lights: 8 light emitting diodes (LED's) which indicate the
operational mode of the instrument, and identify malfunctions.
5. INSTRUCTION Lights: 8 light emitting diodes (LED's) which help the
operator set up the instrument.
6. MANUAL CONTROL Switches:
MANUAL OFF-ON (far left switch): When ON, permits use of 4 remaining
switches (below) to test operation manually.
SHUTTLE MOTOR (second switch from left): When depressed, this switch
will drive the shuttle mechanism motor.
SEAL MOTOR (Middle switch): When depressed, will drive the filter seal
motor.
PUMP MOTOR (second switch from right): When on, will provide power to
both the fine and coarse flow pumps.
51
-------
STATUS LIGHTS INSTRUCTION LIGHTS
PAPER ADVANCE
SWITCH
POWER SWITCH
KEYPAD
CIRCUIT BREAKERS
MANUAL CONTROL 'SWITCHES
Figure 19. Sampler Front Panel Controls
52
-------
TRAY MOTOR (far right switch): When depressed, will drive the tray
indexing motor.
7. HEATER, MAIN POWER and MOTORS Circuit Breakers: Individual circuit
breakers are provided for the following: main power, heater and electric
motors. They trip and remove AC power from the equipment when an
overload exists. To reset, turn the POWER switch off and momentarily
push in on the tripped circuit breaker switch. Turn the POWER switch
back on and make sure it is operating properly. If a circuit breaker
trips again, do not reset. This is an indication that further repairs
are needed.
INTERIOR FLOW CONTROLS
The dichotomous sampler is equipped with a flow meter and flow control
valve for each of the fine and coarse flow circuits, as shown in Figure 20.
The larger flow meter and its valve control the fine flow. This flow is
nominally set at 15 £pm and then carefully set with an accurate flow
calibrator. The coarse flow (smaller flow meter) is then set at 1.7 £pm.
As described in Section 5 of this report, a vacuum pressure gauge should
be installed to provide additional flow measurements.
OPERATING INSTRUCTIONS
This section provides detailed, step-by-step instructions for programming
and operating the dichotomous sampler. An example of a typical sampling
program is given along the right-hand edge of the instructions to assist in
relating sampling requirements to instrument instructions. A simplified
summary of these instructions is given at the end of this section for use as a
guide once the operator is familiar with the instrument.
53
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COARSE FLOW ROTAMETER
FINE FLOW
CONTROL VALVE
FINE FLOW ROTAMETER
CAPS AT FORMER
LOCATION OF
PRESSURE SWITCH
COARSE FLOW
CONTROL VALVE
RECOMMENDED INSTALLATION
OF VACUUM GAUGE
Figure 20.
Interior Flow Controls, Showing Recommended Installation
of Vacuum Gauge
54
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OPERATION
INSTRUCTION
EXPLANATION/EXAMPLE
1.
Record
Keeping
System
Enter appropriate information for logs or
record keeping system to insure that
necessary data for sample collection is
properly supplied and recorded.
2.
Turn On
Plug instrument in and depress power
switch. Immediately, power switch should
light, printer should advance paper
approximately 2", and pump should run
momentarily. Instruction LED's (light
emitting diodes), CALENDAR TIME and DAY
should light.
3.
Set
Calendar
Date
Key in on the keyboard a 3-digit number —
001 through 365 -- corresponding to the
present date. Refer to Figure 21 for
date and corresponding Julian Day to be
used. DAY will turn off, and HOUR will
light.
CAUTION: Operator should note whether
current year is a leap year, i.e., 1980,
1984, etc., and use the appropriate Julian
calendar in Figure 21. The sampler is
designed to print Day #1 after Day #365.
The operator must adjust the dates on the
printed record when sampling at the end of
a leap year. See Figure 21, Part B (Leap
Year Julian Calendar) for more detailed
instructions.
Assume today's date is
March 10, 1980. This
is a leap year, so look
up March 10 on leap
year calendar.
Corresponding Julian
Day is 70. Key in
070.
4.
Set
Calendar
Time
Key in a 2-digit number — 00 through 23 --
corresponding to the present hour. HOUR
will turn off, and MINUTE will light.
Key in a 2-digit number -- 00 through 59 --
corresponding to the present minute.
MINUTE will turn off, and printer will
print out the present calendar date and
time.
Assume time at the
moment is 3:23 pm.
Key in 15 for HOUR and
23 for minutes. Print-
out will be as follows:
DAY HOUR MINUTE
#1 U70 ~I5~~ 23
55
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OPERATION
INSTRUCTION
EXPLANATION/EXAMPLE
Following this printout, the filter shuttle
will automatically retract, and the filter
seal mechanism will open. The tray INDEX
ERROR may then light.
5. The filters are notched in one corner to
Filter insure correct positioning and sealing. As
trays shown in Figure 8, the proper orientation
of the filters is with the notched corner
facing the impactor assembly and away from
the front of the instrument. Also, note that
the fine filter tray is closer to the front
of the sampler and the coarse filter tray
is to the rear. Raise the filter tray
carriage to its uppermost position using
the carriage release knob, and insert both
trays. Tighten the filter carriage
guide bar across the top of the filter
trays. Make sure the trays fit squarely
in the tray holders and against the small
metal tabs in the corner of the tray holders
(See Figure 8).
6. Once the trays are loaded, lower the en-
Tray tire assembly completely. Depress RESET
Position for approximately one second. If trays
are positioned and seated properly, the
INDEX ERROR light will go out, and START
TIME and DAY will light. Depress TRAY
ADV and a two digit number (02 to 36)
of the desired filter for the start of
sampling. The first pair of filters must
always be kept unexposed as a blank.
Assume that sampling
is to begin at tray
position 3. Depress
TRAY ADV and key in
03.
7. Key in a 3-digit number -- 001 through
Sampling 365 -- for the desired starting date
Start of the sample. Refer to correct
Date Julian calendar (Figure 21). DAY will
turn off, and HOUR will light.
Assume the desired
date for sample
collection to start
is March 15, 1980.
Julian day is 075.
Key is 075.
56
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.IUI.1AN CALENDAR SHOWING DATE AND CORKICSKINDINO JULIAN DAY FOR NON-I.FAP YKAR
NOTE: CALENDAR ONLY SHOWS KVliRY OTHER DAY
Jan. 1 1
Jan. 3 3
Jan. 5 5
Jan. 7 7
Jan. 9 9
Jan. 11 11
Jan. 13 13
Jan. 15 15
Jan. 17 17
Jan. 19 19
Jan. 21 21
Jan. 23 23
Jan. 25 25
Jan. 27 27
Jan. 29 29
Jan. 31 31
Feb. 2 33
Feb. 4 35
Feb. 6 37
Feb. 8 39
Feb. 10 41
Feb. 12 43
Feb. 14 45
Feb. 16 47
Feb. 18 49
Feb. 20 51
Feb. 22 53
Feb. 24 55
Feb. 26 57
Feb. 28 59
Mar. 2 61.
Mar. 4 63
Mar. 6 65
Mar. 8 67
Mar. 10 69
Mar. 12 71
Mar. 14 73
Mar. 16 75
Mar. 18 77
Mar. 20 79
Mar. 22 81
Mar. 24 83
Mar. 26 85
Mar. 28 87
Mar. 30 89
Apr. 1 91
Apr. 3 93
Apr. 5 95
Apr. 7 97
Apr. 9 99
Apr. 11 101
Apr. 13 103
Apr. 15 105
Apr. 17 107
Apr. 19 109
Apr. 21 111
Apr. 23 113
Apr. 25 115
Apr. 27 117
Apr. 29 119
May 1 121
May 3 123
May 5 125
May 7 127
May 9 129
May 11 131
May 13 133
May 15 135
May 17 137
May 19 139
May 21 141
May 23 143
May 25 145
May 27 147
May 29 149
May 31 151
June 2 153
June 4 155
June 6 157
June 8 159
June 10 161
June 12 163
June 14 165
June 16 167
June 18 169
June 20 171
June 22 173
June 24 175
June 26 177
June 28 179
June 30 181
July 2 183
July 4 185
July 6 187
July 8 189
July 10 191
July 12 193
July 14 195
July 16 197
July 18 199
July 20 201
July 22 203
July 24 205
July 26 207
July 28 209
July 30 211
Aug. 1 213
Aug. 3 215
Aug. 5 217
Aug. 7 219
Aug. 9 221
Aug. 11 223
Aug. 13 225
Aug. 15 227
Aug. 17 229
Aug. 19 231
Aug. 21 233
Aug. 23 235
Aug. 25 .237
Aug. 27 239
Aug. 29 241
Aug. 31 243
Sept. 2 245
Sept. 4 247
Sept. 6 249
Sept. 8 251
Sept. 10 253
Sept. 12 255
Sept. 14 257
Sept. 16 259
Sept. 18 261
Sept. 20 263
Sept. 22 265
Sept. 24 267
Sept. 26 269
Sept. 28 271
Sept. 30 273
Oct. 2 275
Oct. 4 277
Oct. 6 279
Oct. 8 281
Oct. 10 283
Oct. 12 285
Oct. 14 287
Oct. 16 289
Oct. 18 291
Oct. 20 293
Oct. 22 295
Oct. 24 297
Oct. 26 299
Oct. 28 301
Oct. 30 303
Nov. 1 305
Nov. 3 307
Nov. 5 309
Nov. 7 311
Nov. 9 313
Nov. 11 315
Nov. 13- 317
Nov. 15 319
Nov. 17 321.
Nov. 19 323
Nov. 21 325
Nov. 23 327
Nov. 25 329
Nov. 27 331
Nov. 29 333
Dec. 1 335
Dec. 3 337
Dec. 5 339
Dec. 7 341
Dec. 9 343
Dec. 11 345
Dec. 13 347
Dec. 15 349
Dec. 17 351
Dec. 19 353
Dec. 21 355
Dec. 23 357
Dec. 25 359
Dec. 27 361
Dec. 29 363
Dec. 31 365
Figure 2la Julian Calendar for Non-Leap Year
-------
Ln
oo
JULIAN CAJ.KNDAK SHOW INC DAIT. AND JULIAN DAY FOR UiAPjnJAR_ (I. c-.^ 1980, J984_, etc._)
NOTK: CALENDAR SHOWS ONLY EVF.RY OTHER DAY
.Ian. 1 1
Jan. 3 3
.Inn. 5 5
Jan. 7 7
.Inn. 9 9
.Ian. 11 11
.Ian. 1 ) 1J
.Jan. 15 15
Jan. I/ 17
Jan. 19 19
.Inn. 21 21
Jan. 23 23
Jan. 25 25
Jan. 27 27
Jan. 29 29
Jan. 31 31
Feb. 2 33
Feb. 4 35
Feb. 6 37
Feb. 8 39
Feb. 10 41
Feb. 12 43
Feb. 14 45
Feb. 1ft 47
Feb. 18 49
Feb. 20 51
Fob. 22 S3
Feb. 24 55
Feb. 2h 57
Feb. 28 59
Mar. 2 62
Mar. 4 64
Mar. 6 66
Mar. 8 68
Mar. 10 70
Mar. 12 72
Mar. 14 74
Mar. 16 76
Mar. 18 78
Mar. 20 80
Mar. 22 82
Mar. 24 84
Mar. 26 86
Mar. 28 88
Mar. 30 90
Apr. 1 92
Apr. ) 94
Apr. 5 96
Apr. 7 98
Apr. 9 100
Apr. H 102
Apr. 13 104
Apr. 15 106
Apr. 17 108
Apr. 19 110
Apr. 21 112
Apr. 23 114
Apr. 25 116
Apr. 27 118
Apr. 29 120
May 1 122
May 3 124
May 5 126
May 7 128
May 9 1 10
May 11 132
May 13 1 34
May 15 136
May 17 138
May 19 140
May 21 142
May 23 144
May 25 146
May 27 148
May 29 1 50
May 31 152
June 2 154
June 4 156
June 6 158
June 8 160
June 10 162
June 12 164
June 14 166
June 16 168
June 18 170
June 20 172
June 22 174
June 24 176
June 26 178
June 28 180
June 30 182
July 2 184
July 4 186
July 6 188
July 8 190
July 10 192
July 12 J94
July 14 196
July 16 198
July 18 :uO
July 20 202
July 22 204
July 24 206
July 26 208
July 28 210
July 30 212
Aug. 1 214
Aug. 3 216
Aug. 5 218
Aug. 7 220
Aug. 9 222
Aug. 11 224
Aug. 13 226
Aug. 15 228
Aug. 17 230
Aug. 19 232
Aug. 21 234
Aug. 23 236
Aug. 25 238
Aug. 27 240
Aug. 29 242
Aug. 31 244
Sept. 2 246
Sept, 4 248
Sept. 6 250
Sept. 8 252
Sept. 10 254
Sept. 12 256
Sept. 14 258
Sept. 16 260
Sept. 18 262
Sept. 20 264
Sept. 22 266
Sept. 24 268
Sept. 26 270
Sept. 28 272
Sept. 30 274
Oct. 2 276
Oct. 4 278
Oct. 6 280
Oct. 8 282
Oct. 10 284
Oct. 12 286
Oct. 14 288
Oct. 16 290
Oct. 18 292
Oct. 20 294
Oct. 22 296
Oct. 24 298
Oct. 26 300
Oct. 28 302
Oct. 30 304
Nov. 1 306
Nov. 3 308
Nov. 5 310
Nov. 7 312
Nov. 9 314
Nov. 11 316
Nov. 13 318
Nov. 15 320
Nov. 17 322
Nov. 19 324
Nov. 21 326
Nov. 2 1 328
Nov. 25 BO
Nov. 27 332
Nov. 29 3)4
Dec. 1 336
Dec. 3 338
Dec. 5 340
Dec. 7 342
Dec. 9 344
Dec. 1) 346
Dec. J3 348
Dec. 15 350
Dec. 17 352
Dec. 19 354
Dec. 21 356
Dec. 23 358
Dec. 25 360
Dec. 27 362
Dec. 29 364
Dec. 31 366
Figure 21b. Julian Calendar for Leap Years
Note: The control system for the Beckman Sampler is designed to accept only Julian days up to 365. If
sampling is to occur on Dec. 31 of a Leap Year (i.e.,day nr. 366 in 1980, 1984, etc.),the sampler
will record this day as 001 of the following year. The operator must be aware of this and manually
correct the printer output for day 366 and 001 and then at a convenient point after January 1, the
printer can be set one day back to coincide with the normal non-leap year Julian Calendar.
-------
OPERATION
INSTRUCTION
EXPLANATION/EXAMPLE
8.
Set
Sampling
Start
Time
Key in a 2-digit number -- 00 through
23 -- for the desired starting hour of
of the sample. HOUR will light. Key
in a 2-digit number — 00 through 59 --
for the desired starting minute of the
sample. START TIME and MINUTE will turn
off, and SAMPLE DURATION and DAY will
light.
Assume desired time
for sample collection
to start is 2:30 p.m.
Key in 14 for HOUR
aand 30 for MINUTE.
9.
Set
Sampling
Duration
Time
A.
The following three operations will set
the total time in days, hours and minutes
that the pump will run for each sample
collected.
Key in a 3-digit number — 000 through
365 -- for the number of days (24-hour
increments) over which each sample is
to be collected. DAY will turn off and
HOUR will light.
Assume desired dura-
tion of each collection
is 30 hours. This is
1 day plus 6 addi-
itional hours. Key in
001 for DAY.
Key in a 2-digit number -- 00 through
23 -- for number of additional hours
over which sample is to be collected.
HOUR will turn off, and MINUTE will
light.
Key in 06 for 6
additional hours over
first day.
Key in a 2-digit number -- 00 through
59 -- for the number of minutes over
which the sample is to be collected.
MINUTE will turn off and DELAY TIME
and DAY will light.
Key in 00 for minutes,
as no additional minutes
are desired for sample
collection.
10.
Set
Filter
Delay
Time
The following three operations will set
the total time in days, hours and minutes
between each sample collection. This
time ^s always measured from the beginning,
or start time, of one group of filters to
tfie beginning, or start time, of the nexl
group, and is called the DelayHMme.
59
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OPERATION
INSTRUCTION
EXPLANATION/EXAMPLE
10. Cont.
Set
Filter
Delay
Time
A. Key in a 3-digit number -- 000 through
364 — for the desired number of days
of delay between the sampling start
of each group of filters. DAY will
turn off, and HOUR will light.
Still using our example,
Start Time was set for
2:30 p.m. on March 15.
Six days from March 15
means automatic sampling
will begin again on
March 21 at 2:30 p.m. Key
in 006 for filter group
delay time of six days
from beginning of sample
to beginning of next
sample.
Assume sample
collection is
desired every six
days. This means
six days from the
Tast group of filters
to the start time of
the next set of
TTTters.
Key in a 2-digit number -- 00 through
23 -- for the desired number of hours
of additional time delay between the
sampling start of each group of
filters. HOUR will turn off, and
MINUTE will light.
Since no additional
hours are desired
over and above the
six day delay time,
key in 00.
Key in a 2-digit number -- 00 through
59 -- for the desired number of minutes
of additional time delay between the
sampling start of each group of
filters. MINUTE will turn off, and
GROUP FILTER COUNT will light.
NOTE: If a delay time of 000 days,
00 hours and 00 minutes is keyed in,
the instrument will automatically
switch into a continuous mode,
sampling consecutively through all
35 filter pairs.
Since no additional
minutes are desired
over and above the
six day delay time,
key in 00.
60
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OPERATION
INSTRUCTION
EXPLANATION/EXAMPLE
11.
Set
Filters
per Group
Number
Key in a 2-digit number -- 00 through 36 -•
for the desired number of filter pairs to
be sampled at each sampling time. Note
that each sample actually involves
collection for a filter pair, one coarse
and one fine.
Assume 2 filter
pairs are desired
for each collection,
2 fine and 2 coarse.
Since our sampling
duration has been
set at 30 hours,
sampling time for
for each filter
pair will be 30
hours. Key in 02
for 2 filter
pairs per group.
DAY HOUR MIN DATE
#2 075 14 30 START TIME
00 SAMPLING TIME
00 DELAY TIME
02 FILTER PAIR
per GROUP
#3 001 06
#4 006 00
#5
12.
Veri fy
Calendar
Time vs.
Start
Time
Push CLOCK PRINT key to verify that the
selected Start Date/Time is later than the
Calendar Time. If the Start Time is earlier
than the Calendar Time, go back to operation
#6, and proceed again.
Leave all INSTRUCTION LED's off and
STAND BY on. The instrument will
automatically wait for the Calendar
Time to coincide wth the Start Time,
at which time sampling will begin
automatically according to the programmed
Still using our example
of today's date, being
March 10, 1980, or 070
on the leap year
Julian Calendar.
Assume Start Date/Time
had mistakenly been
entered as March 5,
1980, or 065 on the
leap year Julian
calendar. Lower tray,
depress RESET. Depress
TRAY ADV, key in
starting position
and re-enter correct
Start Date, which is
075, and remaining
data in Steps #2
through #5.
61
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SIMPLIFIED OPERATING INSTRUCTIONS
1. RECORD KEEPING -
Enter appropriate data on all required record
keeping forms.
2. TURN ON -
Plug in instrument and turn on power switch.
3. SET CALENDAR DATE
AND TIME -
Key in a three-digit DATE number - 000
through 365, a two-digit HOUR number - 00 through
23, and a two-digit MINUTE number - 00 through
59 - corresponding to present date and time.
Refer to appropriate Julian Calendar for DATE
entry.
4. LOAD FILTER TRAYS -
Properly insert filter trays. Lower trays
completely. Press RESET for one second.
TRAY ADV -
Press TRAY ADV to advance tray to filter pair
desired (not first pair).
SET SAMPLING START
DATE AND TIME
Key in a three-digit DATE number - 000 through
365, a two-digit HOUR number - 00 through 23, and
a two-digit MINUTE number - 00 through 59, for
desired sampling start date and time. Refer to
appropriate Julian Calendar for DATE entry.
SET SAMPLING DURATION Key in a three-digit number - 000 through
TIME 365, a two-digit number - 00 through 23, and a
two-digit number - 00 through 59, for the total
number of days, hours and minutes of sampling
duration for each sample collected.
62
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8. SET FILTER DELAY Key in a three-digit number - 000 through
TIME 365, a two-digit number - 00 through 23, and a
two-digit number - 00 through 59, for the total
number of days, hours and minutes of desired delay
time between the sampling start of each filter
group. Inputs of zero days, hours and minutes
automatically initiate the continuous sampling
mode.
9. SET FILTERS PER Key in a two-digit number - 00 through 36 for
GROUP NUMBER - the number of filter pairs to be sampled at each
sampling time. If zero delay time is selected in
Step 7, the Filters per Group number is 00.
Following Step #9 (or #8 if delay time is 000 00 00), printer will
automatically print out data which has been entered as follows:
(DAY) (HOUR) (MIN)
n XXX XX XX (Start Time/Date)
#3 XXX XX XX (Sampling Time)
#4 XXX XX XX (Delay Time)
#5 XX (Filters per Group)
9. VERIFY CALENDAR TIME Depress PRINT CLOCK key to see if Start Date/Time
VS. START TIME - are later than Calendar Date/Time. If not
correct, push RESET and repeat Steps 4-7.
STAND-BY will light, indicating sampler is in a "wait" mode and will
automatically begin sampling when Calendar Date/Time Reaches Start
Date/Time.
63
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SAMPLER OPERATION
Once the operating instructions have been entered into the instrument's
microprocessor, the sampler's clock runs until the preselected sample
date/time is reached. At that point the sampler starts automatic control.
The initial setup data are printed, followed by the shuttle mechanism
inserting a filter pair, the seal mechanisms closing, and the flow pump
turning on. Filter number and pumping start time are printed automatically.
Modes of Operation
The dichotomous sampler can be programmed for one of two operating modes:
Group Mode or Continuous Mode. Group Mode is selected with the sampling
program calls for one or more samples to be collected and then for some
interval to pass before another sample or group of samples is collected. For
example, this mode would be used to collect a 24-hour sample every sixth day.
The instrument would be programmed with a FILTER GROUP COUNT of 1, a SAMPLING
TIME of 1 day, and a GROUP DELAY TIME of 6 days. Similarly, if you wanted to
collect a group of three samples every 30 days, the FILTER GROUP COUNT would
be 3, SAMPLING TIME of 1 day, and a GROUP DELAY TIME of 30 days. Note that
the DELAY TIME is the time between the start of each filter group, not the
time between the completion of one group and the start of the next. Following
completion of the last sample of each group, the filter pair will be returned
to the tray and the instrument will go to STANDBY until completion of the
remainder of the GROUP DELAY TIME.
Although the Group Mode is considered the normal operating mode, the
instrument can run in the Continuous Mode as well. This mode is automatically
selected if the GROUP DELAY TIME is set at zero during initial setup. In this
mode the sampler will sequence through all 35 available filter pairs, pumping
for the preselected SAMPLE TIME for each pair, and automatically changing to
the next unexposed filter pair as soon as the SAMPLE TIME is completed.
64
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There is a disadvantage in using the Continuous Mode. In this mode the
25 seconds needed to change filters are not included in any of the selectable
time intervals, which will cause the start times for a sequence of filters to
lag increasingly. If one wants to sample continuously, on a fixed schedule,
then use the Group Mode, and set the sampling time to be 1 minute less than
the desired time between filter changes. The following are some examples:
Example 1: Continuous sampling with filter changes every midnight starting on
day 160.
Day Hour Minute
160 00 00 Start Time
000 23 59 Sampling Time
001 00 00 Delay Time
01 Filters per group
Example 2: Continuous sampling with filter changes at 7:00 a.m. and 7:00 p.m.
starting on day 80:
Day Hour Minute
080 07 00 Start Time
000 11 59 Sampling Time
000 12 00 Delay Time
01 Filters per group
Filter Overload
The pump will continue to run for the programmed sampling duration unless
a filter overload occurs. This is determined by the differential pressure
switch. If the fine particulate flow rate drops by more than .75 £/min (5% of
the normal flow rate of 15 £pm), a signal from the switch terminates the
pumping cycle. The filter pair is returned to the tray, and the calendar
date/time is printed on the printing tape. A symbol "v" is also printed to
identify the overload (refer to Figure 22). The next filter pair is inserted,
and pumping resumes. The pumping time for this second set of filters will be
65
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CODE DAY HR MIN
»o 1 9 R 1 n n 7 -« .
t 1 t O 1 U U j
»^ nnn n < n n -«--
J UUU UOUU *^~-
»L nni nnnn-«
B^ n 9 «
j V C ^
B1 128 1 Q Q Q -• -.
« 2 128 1003]
» 3 000 0600
» 4 001 0 0 0 0 '
» 5 0 2J
FILTER"
WU. JJAY HR MIN CODE
01 128 1001 S-*-
01 128 1003 T^.
02 128 1003 S
02 128 1003 M^
03 128 1004 S
03 128 1004 *-«-
04 128 1004 S
28 1004 -
128 1005 +-*-
04 128 1006 T
01 128 1008 S
01 128 1008 X-*
PROGRAMMED INPUT
..Sampler Start Date/Time
— — — S(imn liner TTTTI^ nr»T Filffti- P-i-i-r
Group Delay Time
- -_ FlIfPT riTnnn Pnnn t~
Calendar Date/Time
Automatic Printout at Sampler Start
OPERATIONAL PRINTOUT
••Pumping Tetmiuate DciLe/Time
Fine Filter Already Clogged
Figure 22. Example of Printer Printout Showing Programmed
Input Instructions and Operational Outputs
66
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the balance of the programmed sampling time. The sampling time will not
include the time necessary to switch filters, which is only about 25 seconds.
If a second overload occurs before the end of the sampling duration, the
filters will again recycle. Pumping time on the third set of filters will be
the time remaining in the programmed sampling time.
If an overload occurs during Group Mode operation, the filters are
recycled, and the follow-on filter pair is counted as one sample of the filter
group count.
Interrupt Procedure
The interrupt sequence allows the operator to interrupt a pumping cycle,
change filter trays, and/or preselect filter, and then to continue sampling
with the existing instructions intact. See INTPT key operation description
below.
Power Failure
In the event of a power failure, a battery will continue to supply power
to the microprocessor, and the system wil continue in the same mode and
sequence as before loss of power. NOTE: The battery has a capacity of 30
minutes; if power is off for a longer period, the sampler instructions will
have to be reset once power is restored.
When all lights are off, the filter trays may be changed, since the
carriage assembly will automatically reset at Filter #1. Once the new tray is
inserted, the sampler will continue with Filter #1 if the CONT key is pushed.
Since Filter #1 must always be left unexposed, do not press CONT. Instead,
depress the TRAY ADV key followed by any two-digit number 02 through 36 for
the filter number that sampling is to continue on. The tray will advance to
the selected filter. When the tray stops, press the CONT key, and sampling
will continue in the original timing sequence.
67
-------
The pumping on the first filter after the interrupt cycle is the balance
of the initial pumping interval. The interrupt sequence is noted by the
symbol "X" on the printer output. Figure 23 shows a typical interrupt timing
cycle.
Printer Output Format
The printer tape provides the sampler test history for each sample cycle.
Data for each printout consists of a code number or filter number, date/time
data, and sampler function designator. Figure 22 shows a typical printout.
KEYPAD OPERATION
INTPT (Interrupt) Key
INTPT key interrupts the sampler during automatic cycling and forces the
program into a "wait" mode. The key is not active during the automatic
sampler operation. Depressing the key does not affect initial input program
data. Instrument operation following actuation of the INTPT key depends on
the operating mode at the time the key is depressed.
Actually, the INTPT key during sampling terminates the sampling mode,
recycles the filters to the tray, and puts the sampler in a "wait" mode.
Actuating the INTPT key during the filter insertion cycle or during the
seal closure cycle results in a 5-second pumping time followed by the seal
opening and recylcing filters to the tray. The designator "X" and calendar
date/time information are printed at completion of the pumping cycle.
Actuating the INTPT switch during the seal opening cycle or during the shuttle
return cycle forces the instrument into the "wait" mode after the filters are
recycled to the tray. "X" designator is not printed.
68
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« 2 226 1332
» 3 000 0005
*4 000 0000
It 5 36
0 1
0 1
2 0
20
2 1
2 1
0 1
0 1
0 2
0 2
226
226
1332
1333
226
226
1337
1337
34 226
34 226
35 226
35 226
1343
1344
226
226
1348
1353
S
X
226 1335 S
226 1337 T
S
x
1341 S
1342 T
S
x
226 1344 S
226 1348 T
S
T
•Start Date/Time
•Sample Time - 5 minutes
Zero Delay - Continuous Mode
Start-Filter #1
INTPT
Tray Advanced to Filter #20
Start Pumping #20
Terminate Pumping - 5 minutes from
Start of Filter #1
• Start #21
• INTPT
Advance Tray to Filter #34
Start #34
Terminate Pumping - 5 minutes from
Start of #21
• Start #35
INTPT
Insert New Filter Tray
Start Filter #1
• Terminate #1-5 minutes from
Start of #35
Start #2
Terminate #2 after 5 Minutes of
Pump ing
Figure 23. Typical Printer Output for Interrupt Cycle
69
-------
PRINT CLOCK Key
Depressing the PRINT CLOCK key prints the current calendar date/time
information. This key is disabled only during printer operation and is active
at all other times. A typical clock printout is shown in Figure 23.
RESET Key
Depressing the RESET key terminates the sampling mode, recycles the
filters to the tray, and resets all input program data. RESET key is active
at all times after initially entering the calendar date/time information.
Resetting the sampler will cause a TRAY INDEX error signal if the RESET
key is actuated while sampling filter pairs other than Pair Number 1.
Following filter recycle the trays must be lowered to position 1 and, the
RESET key must be depressed before entering operating data.
TRAY ADV (Tray Advance) Key
This key is used in conjunction with the INTPT key to allow selection of
a specific filter pair for the next sampling position. NOTE: The key is
active only if the calendar time is set, the trays are in position 1, and the
tray index error light is off.
TEST Key
The TEST Key selects the instrument self-test mode. Depressing the TEST
key followed by a numerical key selects a specific self-test routine. This
key is active only at power on, before entering calendar clock data, and
following the completion of sample Pair Number 36. The key is inactive during
sampler operation.
70
-------
CONT (Continue) Key
This key restarts sampler operation under the initial timing parameters.
The key is active only after depressing the INPT key and following sample
completion of filter Pair Number 36.
71
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SECTION 7
QUALITY ASSURANCE
Throughout this report are instructions, recommendations, and cautionary
notes which will greatly improve the quality of data produced, if they are
followed carefully. In addition, the checks and audits prescribed below
should be incorporated into the operator's quality control program.
NOTE: The weekly flow check and six-month flow audit can be performed using
suitable calibrated rotameters, limited orifice, dry test meters, or similar
flow measuring devices. The instructions below are for use with the 604 and
603 rotamters, but similar procedures would be followed in using the other
instruments.
Weekly Flow Check
During periods of routine operation, the flow should be checked and set
as follows on a weekly basis. Note: flow checks should be made during normal
sampling operations.
1. Place the 604 rotameter and adaptor assembly on the inlet of the sampler.
Measure and record the total flow. Also record both the fine and coarse
rotameter settings and the vacuum gauge reading.
2. With the 604 rotameter in place, turn the coarse flow off. Record the
604 rotameter and fine rotameter readings.
72
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3. Turn the coarse flow back on, and adjust it to the proper set point
determined from the most recent calibration.
4. Adjust the fine flow to the proper set point determined from the most
recent calibrations.
5. Again read the 604 rotameter for total flow. If the total flow differs
by more than 0.25 £pm from 16.7 £pm, adjust the fine flow until the
proper reading is obtained on the 604 rotameter. Make sure that the
coarse flow rotameter is still at its proper set point.
6. Record total flow and vacuum gauge readings after final adjustments have
been made. Figure 24 shows a typical data log form for use in weekly
checks.
Weekly Tape Check
During the weekly flow checks described above, the operator should check
the printer output to see that the information shown matches the programmed
instructions. The results of this check should also be recorded, using the
form shown in Figure 24 or other suitable log.
Six-month Flow Audit
Every six months the coarse, fine, and total flows of the dichotomous
sampler must be checked with an independent calibration system using the
procedure below. The filter overload cutout switch setting should be checked
at the same time. A 604 and 603 rotameter adaptor tube assembly other than
the units normally used for routine calibration purposes, or some other type
of independent calibration equipment, should be used. All audit results must
be recorded on an audit log. One copy is kept on file at the site, and one is
returned to the agency which processes the audit results. Figure 25 shows a
typical form for recording this audit information.
73
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AUTOMATIC DICHOTOMOUS SAMPLER AT LAST CALIBRATION: (AT INLET)
WEEKLY LOG CUTOFF SWITCH SET AT (L/M)
City Coarse pts. Fine pts . (604) Total pts ,
EPA Site No. Roto Flow Roto FLow Roto Flow
EPA Serial No.
Instrument Mfr.
Inst. Model No.
Inst. Serial No. ^^^^^^^ ^^^^^^^ ^]^^^^
Date of Last ^^^^^^_ ^^^^^^^ ^^^^^
Calibration
Sample Time
Setting Total/Fine Course
Delay Time Calib 604 Calib 603
Group Filter Count Ser. No. Ser. No.
Last Cleaning (Date) Last Calib. Last Calib.
Atm. Press Atm. Press
By By
Coarse Tray No. Fine Tray No. Tray Type
Start Date (Julian Day)
Start Date (Mo/Da/Yr)_
Start Hour
Fine Flow (Roto/Flow)
Coarse Flow (Roto/Flow)
Total Flow (Coarse + FiSeT
Coarse Sample I.D. No.
Fine Sample I.D. No.
Duration of Run (Hrs, Min, Sec)
Coarse Sample I.D. No. '_
Fine Sample I.D. No.
Duration of Run (Hrs, Min, Sec)
Sample Time and Date Checked
Against Tape? (Date + Time)
Operator's Initials Date
Wkly Flow Check With 604 COMMENTS:
BFR adj. AFT adj.
Tot. flow
Fine flow
Diff.
L/M
L/M
L/M
L/M
L/M
L/M
(coarse)
VAC.
Figure 24 Suggested Weekly Log Form
74
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DICHOTOMOUS SAMPLE FLOW RATE AUDIT
Type of Sampler
Section
Rev. 1 12/79
Page 3 of 3
Form
Audit Calibrators
AGENCY
CITY
Dichot.
SER. NO.
SITE #
DATE
AUDITOR
LAST CALIB._
CURR. TEMP._
CURR. PRESS._
BY
Total/Fine
Calib. 604
SER. NO.
LAST CALIF, .
TEMP.
MM. PRESS.
3Y
coarse
Calib. 603
SER. NO.
LAST CALIB.
TEMP .
ATM. PRESS.
BY
^OTAMETERS USED AT LAST CALIB.: SERIAL ft 604
X 603
All tests to be performed through filters at inlet on a normal sampling day.
fVudit Calib. Readi
Total Flow:
504 Roto =
:oarse Off:
504 Roto «
Difference:
Pine Flow :
504 Roto Settings
Coarse Flow:
503 Roto Settings
504
roto: , ,
ngs
Flow L/Min.
Dichot. Readings
Fine Roto =
Coarse Roto =
Total Flow
Coarse Off:
Fine Roto =
:xi
Fine Roto
Coarse Roto
cut off switch
set at U/M)
Flow L/Min.
Percent Difference
Difference
1.
2. f:
3.
4.
The following information pertains' to the sample which was present on the
monitor during this particular QC inspection:
STATION OPERATOR
OC INSPECTOR
DATE OF SAMPLE
STARTING TIME (MIN. )
ENDING TIME (MIN.)
COMMENTS:
Figure 25 Suggested Flow Rate Audit Form
75
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1. Total flow: Place the audit inlet adapter, with the valve fully open
(counterclockwise) and the 604 Rotameter attached onto the inlet of the
dichotomous sampler impactor. Tighten the hose clamp and proceed as
follows:
a. First, measure the total flow as indicated by the 604 rotameter and
log it on the form. Log the dichotomous fine flow rotameter and
coarse flow rotameter readings and their corresponding flows that
the sampler is currently operating at as determined by your last
calibration.
b. Next, turn the coarse flow fully off and log the 604 rotameter
reading and the fine flow rotameter reading.
2. Fine flow: With the coarse flow off, set the fine flow to read each of
the four 604 rotameter set points as noted on the audit form. Log both
the fine flow rotameter readings and the fine flow in £/min as determined
by the last calibration for each of the 604 rotameter audit set points.
3. Coarse flow: Next, reset the coarse flow rotameter to its normal set
point and turn the fine flow completely off. Replace the 604 audit
rotameter with the 603 audit rotameter and proceed to check each of the 4
audit set points. Log the 603 rotameter readings and the coarse flow
rotameter values and their corresponding flows as determined by the last
calibrations.
Filter Overload Cutout Switch Check
Once the six month flow audit has been completed, the filter overload
cutout switch setting should be checked. Refer to the instruction for this
check in Section 5, Checkout and Calibration.
Finally, return the sampler to its normal operation setting. Void the
filter set that was running on the day of the audit and program the unit to
76
-------
run on the next scheduled sampling day. Within one week after this audit is
performed, the impactor head assembly should be removed and cleaned in
accordance with the procedure described in Section 8 of this manual.
Six-Month Control Check
Every six months control checks must be peformed on at least 5% of the
data being collected. The checks must compare the data obtained from the
computer output to the raw data recorded on the weekly logs. Coarse, fine,
and total mass calculations must be confirmed from raw data.
77
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SECTION 8
MAINTENANCE
SCHEDULE FOR ROUTINE MAINTENANCE
On a yearly basis (or after every 180 24-hour days of operation), the
operator should perform the following maintenance:
1. Replace the Thomas pump diaphrams.
2. Inspect and replace if necessary the shock mounts on the Thomas pump.
3. Clean the exhaust filters on the Thomas pump.
4. Lubricate the lock assembly on the front access door.
5. Replace the inlet tube connector.
Every six months (or after every 90 24-hour days of operation), the
operator should perform the following maintenance:
1. Clean the impactor assembly.
2. Clean the inlet tube and fractionating inlet.
3. Perform a multipoint flow calibration on the coarse and fine flow systems
as described in Section 5 of this report.
78
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MAINTENANCE INSTRUCTIONS ~ YEARLY MAINTENANCE
1. In performing the suggested yearly maintenance, it is necessary to remove
the entire sampler housing to provide access to the pumps and exhaust
filters. Unplug the sampler power cord, and remove the 10 socket head
cap screws which attach the housing to the instrument chassis. Remove
the inlet tube, and carefully lift the housing straight up until it
clears the instrument.
2. Diaphram Replacement:
a. Remove the large fine flow accumulator canister located directly
above the Thomas Pump.
b. Disconnect the polyethylene vacuum tubing which is attached to the
pump with a worm drive clamp.
c. Remove the four screws in each diaphram head of the pump (eight in
total).
d. The diaphrams are visible once the pump heads have been lifted off
the pump.
e. Replace both diaphragms and reassemble the pump.
3. Shock Mount Inspection: After replacing the pump diaphragms, thoroughly
inspect the shock mounts for cracks, torn surfaces, or other signs of
fatigue. Replace the mounts, if necessary.
4. Exhaust Muffler Cleaning:
a. After replacing the pump diaphragms, run the pump for five minutes.
79
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b. Turn the pump off and remove the exhaust mufflers. Soak them for
five minutes in a solvent such as alcohol. After soaking
thoroughly, dry the mufflers by blowing them out with air flow in
the reverse of their normal flow. Replace the filters if there is
any indication of clogging.
c. Reassemble the system.
5. Lock Lubrication: Lubricate the key-way on the front access door with
Lock Ease, oil or some other lubricant designed for locks.
6. Replacement of Inlet Connector: Inspect the inlet connector for signs of
wear and abrasion. Replace the clear plastic tubing if it is worn or if
there are any indications of leaks. The inlet tube should slide into the
plastic connector with some resistance; if the fit is not tight, replace
the connector tube.
MAINTENANCE INSTRUCTIONS - SEMI-ANNUAL MAINTENANCE
1. Impactor Assembly Cleaning:
a. Remove the four screws which attach the impactor assembly to the
instrument deck.
b. Disassemble the impactor by removing the four screws which hold the
impactor together and pulling it apart, as shown in Figure 26.
c. Thoroughly and gently clean all surfaces of the impactor and seals
with an ethyl alcohol dampened cloth or lint-free paper towel.
d. Gently wipe the silicon rubber seals of the lower portion of the
filter seal mechanism which remains on the main deck assembly after
the impactor has been removed with an alcohol-dampened towel or
cloth.
80
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Figure 26. Virtual Impactor Disassembled for Cleaning
81
-------
e. Reassemble the impactor, making sure that the red rubber gasket is
properly in place, before tightening the screws. At all times be
careful never to place the silicon rubber filter seals on any
surface where they may be damaged p_r soiled.
NOTE: Unusually heavy filter loadings resulting in values greater
o
than 100 ug/m will necessitate a more frequent schedule (e.g.,
every 45 days).
2. Inlet Tube and Fractionating Inlet Cleaning:
a. Remove the inlet assembly from the sampler where it attaches to the
inlet tube clear plastic connector.
b. Disassemble the fractionating inlet and throughly wash it with a
mild detergent.
c. Thoroughly dry the inlet with a lint free cloth and reassemble the
unit.
82
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SECTION 9
TROUBLESHOOTING
Suggestions for troubleshooting are included with the checkout and
calibration instructions in Section 5 of this report. For additional
troubleshooting instructions, the operator should refer to the manufacturer's
Operating and Service Instructions (2). Problems beyond the scope of those
instructions should be referred directly to the manufacturer.
83
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REFERENCE LIST
1. Adapted from K.T. Whitby and B. Cantrell, "Atmospheric Aerosols -
Characteristics and Measurements," in International Conference on
Environmental Sensing and Assessment, Las Vegas, NV, September 14-17,
1975, Institute of Electrical and Electronics Engineers, New York, 1976.
2. "Automated Dichotomous Particulate Sampling System: Operating and
Service Instructions," Beckman Instruments, Inc., February 1979.
3. Olin, John G., "A New Virtual Impactor (Dichotomous Sampler) for Fine
Particle Air Quality Monitoring," presented at the 71st Annual Meeting of
the Air Pollution Control Association, Houston, Texas, June 1978.
4. Loo, B.W., Adachi, R.S., Cork, C.P., Goulding, F.S., Jaklevic, J.M.,
Landis, D.A., and Searles, W.L. "A Second Generation Dichotomous Sampler
for Large Scale Monitoring of Airborne Particulate Matter." Lawrence
Berkeley Laboratory Report LBL - 8725, Berkeley, CA, January 1979.
5. "Ambient Air Quality Monitoring, Data Reporting, and Surveillance
Provisions," U.S. Environmental Protection Agency, Federal Register,
44:27557, May 10, 1979.
6. Ludwig, F.L. Kealoha, J.H.S., and Shelar, E. , "Selecting Sites for
Monitoring Total Suspended Particulates," EPA Publication No.
EPA-45012-118, June 1977.
84
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APPENDIX I
PARTS AND ACCESSORIES
OPERATING ACCESSORIES
1. Vacuum Gauge:
1 ea. #V500 V LM #47103
30" Hg Vacuum Gauge with Screw Check
Available from: Boston Cooper
Salem Industrial Park
Manor Parkway
Salem, New Hampshire 03079
Tel: (603)893-9181
2. Pump Muffler:
2 ea #4450 KI 1/8" Pipe Thread
Combination muffler/filter
Available from: McMaster Carr Supply Co.
Post Office Box 4355
Chicago, IL 60680
Tel: (312) 833-0300
3. Inlet Connector:
3 feet #PV2620-1 IV Nominal ID x 3/16" wall
Par Fex Clear Plastic Tubing
85
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Available from: Green Rubber Company
160 Second Street
Cambridge, MA 02142
Tel: (617) 547-7658
4. Standpipe Extension:
As mentioned in Section 4, installation of the Sampler indoors
requires an extension to the inlet standpipe and a supporting
sleeve. Since the length and material for these accessories will
depend on the location and type of sampling required, specifications
are not provided here. The standpipe extension should be of IV
nominal outside diameter pipe with a 1" nominal inner diameter.
Depending on the material selected, pipe and tubing for this purpose
should be readily available locally at heating or plumbing
suppliers.
CALIBRATION ACCESSORIES
1. Singer Dry Test Meter:
1 ea. Dry Test Meter Model #DTM-115-3 with Dial Temperature and
Pressure Gauge
Available from: American Meter Division
13500 Philmont Avenue
Philadelphia, PA 19116
2. Rotameter Assembly (604):
1 ea. Model #7630H Rotameter with 604 Tube
1 ea. Model #7966 Bench Stand
1 ea. h" diameter Tantalum Float for 604 Tube
86
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Available from: Matheson Gas Co.
Post Office Box 1147
61 Grove Street
Gloucester, MA 01930
Tel: (617) 283-7700
3. Rotameter Assembley (603):
1 ea Model #7630H Rotameter with 603 Tube
1 ea. Model #7966 Bench Stand
Available from: Matheson Gas Co.
(See address above)
4. Inlet Filter for 603 and 604 Rotameters:
2 ea. #4450 Kl 1/8" Pipe Thread
Combination muffler/filter
Available from: McMaster-Carr Company
Post Office Box 4355
Chicago, IL 60680
Tel: (312) 833-0300
5. Inlet Adaptor Assembly (Instructions are given after the specifications):
6 feet V ID x V wall Latex Vacuum Tubing
Available from: Irving B. Moore
30 Rindge Avenue
Cambridge, MA 02139
Tel: (717) 491-0100
1 ea. #B-4-FHC-2T Tapered Female Connector
2 ea. #8-600-7-4 Female Connector
3 ea. #B-4-MHC-6T Tapered Male Connector
1 ea. #B-4-HN Hex Nipple
1 ea. #B-IRF4-A Regulating Valve
87
-------
Available from: Cambridge Valve and Fitting
50 Manning Road
Bill erica, MA 01824
Tel: (617) 272-8270
2 feet Schedule 80, 1" Nominal Diameter Type 1 PVC Pipe
2 ea. Schedule 80, 1" Nominal Diameter Socket Caps
1 pint "80" PVC Cement
Available from: Utility Supply Corporation
425 Riverside Avenue
Medford, MA
Tel: (617) 395-9023
-------
INSTRUCTIONS FOR ASSEMBLY OF INLET CALIBRATION ADAPTOR FOR USE WITH ROTAMETERS
The assembly is shown in Figure 15.
1. With PVC cement, attach a 20-inch length of Schedule 80 1" nominal
diameter pipe to a 1" nominal diameter socket cap which has been drilled
and tapped to V NPT. Remove all burrs from the open end and use the
second 1" cap as a dust cap (do not glue it on).
2. Attach the brass regulating valve's outlet to a V NPT hex nipple.
3. Attach the valve and hex nipple to the socket cap on the tube assembly
(do not overtighten the brass to PVC connection).
4. Attach a V NPT tapered male connector to the inlet of the brass
regulating valve.
5. Use Teflon tape on all pipe-connections.
6. Attach the adaptor assembly to the 604 or 603 rotameter using V ID and
V wall latex vacuum tubing.
89
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APPENDIX II
CORRECTION OF ROTAMETER READINGS TO
ACTUAL PRESSURE AND TEMPERATURE
The flowmeters described in this manual are manufactured by Matheson.
They come with the manufacturer's calibration for air at 70°F (21.1°C) and at
atmospheric pressure. We recommend recalibration of all flow measurement
devices to a traceable reference standard. The procedure described below is
required to convert the calibrated flow readings to actual conditions.
When calibrated rotameters are used at another pressure or at another
temperature from the calibration conditions, it is necessary to adjust flow
readings for these changes. Departures from calibration conditions result in
a change in drag forces on the float ball. These changes are due primarily to
changes in density (pressure and/or temperature affected) and changes in air
viscosity. Actual flow (operating conditions) is the product of the reading
for air times the density factor times the change of flow due to viscosity
differences.
ACTUAL FLOW = FLOW READING x DENSITY FACTOR x % OF FLOW CHANGE DUE T0 VISC-
100
DENSITY FACTOR (DF)
Tl P? fc
DF = [ -i -? ]*
T P
'2 Hl
T! = 294.3°K (273.2 + 21.1°C) or calibration temperature
T~ = Operating Temperature (°K)
P, = Standard atmospheric pressure (14.7 psia) or calibration pressure
may be expressed in any units of pressure
Pp = Actual atmospheric pressure
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VISCOSITY FACTOR (VF)
The viscosity factor is calculated by dividing the dynamic viscosity in
centipoise of air at operating conditions by the density of air at atmospheric
pressure. The viscosity of air is independent of pressure for the normal
range of surface pressures. The viscosity of air is a function of temperature
as shown in Figure A-l where temperature is in degree centigrade and viscosity
is in units of centipoise.
_o
Viscosity is divided by density of air at atmospheric presure (1.2 x 10
grams per cubic centimeter). The simplified formula for the viscosity factor
includes these terms times a pressure and temperature correction term.
VF = 833 (Viscosity)/DF
Figure A-2 is then used to determine the percent of flow calculated. This is
determined by following the viscosity factor calculated across to the "float
curve" and then up to the horizontal axis to determine the correction factor.
Sample Calculations
Air Temperature: -10°C (14° F) or 263.2 °K
Pressure: 850 mb, 637.5 mm Hg, or 29" Hg
Density Factor: [(294.3/263.2) x (29.0/29.92)]^ = 1.04
Viscosity Factor: 833 x 0.01657/1.04 = 13.04
On Figure A-2 using a glass float gives a percentage correction of 104%
ACTUAL FLOW = Reading x 1.04 x 1.04
= Reading x 1.08
or approximately +8%
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Sample Calculation
Calibration temperature Tj = 25°C (77°F) (298.2°K)
Actual temperature T2 = 0°C (32°F) (273.2°K)
Calibration pressure P., = 790 mm Hg (31.1 inches Hg)
Actual pressure P2 = 650 mm Hg (25.59 inches Hg)
Density Factor = [(298.2°K/273.2°K) x (650 tm/790m^ = 0.95
Viscosity Factor = (833 x 0.01709)70.95 = 15
From Figure A-2 the correction factor is essentially 100% of flow (or no
change due to viscosity differences).
ACTUAL FLOW = Reading x .95 x 1.00
or approximately a -5%
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U>
.0190
.0180
.0170
.0160
Figure A-l (Centipoise) of air as a function of temperature (°C/°F)
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§ a 8 s s
94
0 US GOVERNMENT PRINTING OFFICE 1961 757-064/0314
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