CONSTRUCTION DETAILS
OF
ISOKINETIC SOURCE-SAMPLING EQUIPMENT
by
Robert M. Martin
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Programs
Research Triangle Park, North Carolina
April 1971
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The APTD (Air Pollution Technical Data) series of reports is issued by the Office
of Air Programs, Environmental Protection Agency, to report technical data of
interest to a limited number of readers. Copies of APTD reports are available
free of charge to Federal employees, current contractors and grantees, and non-
profit organizations - as supplies permit - from the Air Pollution Technical Infor-
mation Center, Environmental Protection Agency, Research Triangle Park, North
Carolina 27711 or may be obtained, for a nominal cost, from the National Technical
Information Service, 5235 Port Royal Road, Springfield, Virginia 22151.
Publication No. APTD-0531
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LIST OF FIGURES
FigU" Page
1. Meter Box Case Construction Diagram 7
2. Meter Box Case Bottom Construction Diagram 3
3. Meter Box Panel Hole Pattern Diagram 9
4. Orifice Construction Diagram 11
5. Meter Box Wiring Diagram 13
6. Leveling Device Construction Diagram 14
7. Optional Solenoid Assembly Diagram 14
8. Sample Box Construction Diagram, Plywood Parts 16
9. Sample Box Construction Diagram, Masonite and Pentafoam Parts . . 17
10. Three-Dimensional View of Sample Box 18
11. Impinger Bath Area 19
12. Sample Box Wiring Diagram 20
13. Umbilical Cord Construction Diagram 22
14. Pitobe Construction Diagram 25
15. Source-Sampling Cyclone 28
16. Sectional View of Filter Holder .................. 29
111
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LIST OF TABLES
bie
1
?
3
4
*
A
7
8.
Materials for Meter Box Construction .......
Plumbing Parts List for Meter Box .
Electrical Parts List for Meter Box
Electrical Parts List for Sample Box .
Parts List for 25-Foot Umbilical Cord
Pitobe Parts List
Glassware Parts List . .
Imoineer Connector Parts List
Page
6
, . 10
12
19
22
24
27
....... 29
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CONTENTS
Page
INTRODUCTION 1
METER BOX CONSTRUCTION 3
Wood Parts 3
Plumbing Parts ,.......,....,., 3
Electrical Hookup 4
Finish Details 5
Optional Solenoid Valve Assembly 5
SAMPLE BOX CONSTRUCTION 15
UMBILICAL CORD CONSTRUCTION 21
PITOBE CONSTRUCTION 23
Pitot « • 23
Probe Glass . 23
GLASSWARE 27
CALIBRATION PROCEDURES FOR ORIFICE AND METER 31
Terminology 31
Procedures 31
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CONSTRUCTION DETAILS
OF
ISOKINETIC SOURCE-SAMPLING EQUIPMENT
INTRODUCTION
The following discussion *was prepared in order that interested persons in
local air pollution agencies might build ila..r own source-sain; 1:ig equipment. -
This equipment was designed and has beer* used since 1967 by employees of the
U.S. Environmental Protection Agency's Air Pollution Control Office (APCO).*
In a field test, the equipment was run for two 24-hour periods without encountering
any malfunctions. APCO Publication No. APTD-0576, Maiatenance. C alibration,
and Ope ration ofla okineti c Source -Sampling Erui-wnent, is recommended for use
when the equipment becomes operational.
The ideas and experiences of numerovs people, gained from many tests on
a, • riety of sources, contributed to the design of this equipment. Although, per-
formance has been satisfactory in most instances, this equipment, like most, can
still be improved.
A similar set of equipment is available commercially. It is being marketed
for approximately $2,200 (19T"> p-ice). The commercial package includes the
meter box, umbilical cord, sample box with glassware, and a probe.
^Formerly the National Air Pollution Control Administration,
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METER BOX CONSTRUCTION
WOOD PARTS
Cut out the sides and top of the case from exterior grade 3/8-inch-thick ply-
wood according to the specifications in Table 1 and Figure 1. Apply a good grade
of casein or resorcinol glue, and nail these three parts together with 1-inch brads.
Cut out and attach the back to this assembly. Cut the panel supports from pine,
and glue and nail them to the inside of the case. Next, cut out the bottom (Figure
2) from 1/2-inch-thick exterior plywood, and make the I/4~inch-wi.de groove for
insertion of the panel.
Cut the bottom frame from 1- by 1-inch aluminum angle (Table 1), and weld
the underside of each of the four corners. Drill and countersink 12 holes, 3 in
each piece; and attach the frame to the underside of the bottom with 1/2-inch flat-
head screws. Figure 2 shows construction details for the meter box case bottom.
Cut out the panel from 1/4-inch-thick tempered Masonite, * and drill the
holes according to the dimensions and pattern shown in Figure 3. Dimensions of
some of the components and hole diameters may differ in size from those on the
figure because of equipment changes. Check sizes before making the holes.
PLUMBING PARTS
Table 2 shows the parts that are necessary for the installation of the plumb-
ing. Bolt the pump to the bottom with 1/4- by 1-inch bolts. Remove the oiler that
comes with the pump and install a 1/4-inch-diameter plug in the oiler inlet hole.
Attach a 1/4-inch male pipe to the 3/8-inch sweat adaptors in the top inlet and out-
let ports of the pump.
Install the two valves and the 1/2-inch quick disconnect on the panel; they
support the panel temporarily in place while the piping is being located. Cut and
fit the pipe from the quick disconnect up to the valves and over to the vacuum gauge.
Modify the oiler by drilling a 1/4-inch hole through the body and inserting a pipe
cleaner for a wick. The wick should point in the direction of airflow to achieve the
desired capillary action of oil. Attach this assembly to the tee between the valves,
*M«ntion of a specific company or product does not constitute endorsement by the
U. S. Environmental Protection Agency,
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and join it to the pump; continue installing the piping up to the meter. Tighten and
solder all connections; use Teflon tape on all threaded joints.
The meter can be attached in a number of ways; the simplest is by the use
of pipe adaptors. The fittings that hold the thermometers must be drilled out to
5/32-inch in order to hold the thermometer stems. The thermometer used on the
inlet side of the me'^r must be bent slightly in order to clear the meter mechanism
as it cycles. The the:—nometers are secured in the Swagelok fittings with Teflon
ferrules. Fabricate and install the orifice as shown, in Figure 4. The orifice can
be enlarged after construction to achieve a better calibration. This procedure
will be discussed further in the i»ction on calibration. Shape a piece of Pentafoam
so that it can be used as a shock-absorbing wedge betv?een the meter and the pump.
Keep the size of the foam to a minimum to avoid interference with the cooling air-
flow.
Attach the manometer to the panel with two 1/4- by Z-inch bolts. Mount the
optional solenoid valves on a piece of 1/4-inch plywood, and attach this assembly
to the hack of the panel. Complete the attachment of the Tygon tubing from the
orifice and of the pitot disconnects to the solenoid valves and manometer. This
completes the piping. The fan is attached to the plumbing by means of clips
soldered to the tubing.
ELECTRICAL HOOKUP
Refer to Table 3 for a list of the necessary electrical components. Remove
the panel from the base, and mount lights, switches, timer, powerstat, and buzzer
on it. Begin the electrical hookup with the power cord, and follow wiring instruc-
tions in Figure 5. Insert a piece of metal behind the powerstat, and ground it to
the frame of the timer, Also ground the pump and timer to the power cord through
the timer frame. Double-check the wiring to the Amphenol fittings for proper
orientation. Then hook up the SPDT switch to the solenoid valves on the mano-
meter zero assembly. Plug in and test all circuits for proper operation. Use an
electric drill or voltmeter to check the operation of the powerstat through the
Am phenol connector. Adjust the timer connection so that the buzzer and pilot
light operate approximately for 15 seconds at the start of each 5-minute interval,
Replace the panel, connect the pump and fan wires, and test,
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FINISH DETAILS
Place the case over the assembly, and locate the thermometer and fan holes.
Cut out the fan holes, and cover with, a screen or grill of your choice. Cut out the
thermometer windows, inlay the Plexiglas disks, and glue into place. Attach
handles as desired. Cut away, with a bandsaw, any unnecessary portion of mano-
meter, and mount the latter on the panel with 1/4- by 2-inch machine screws.
Keep the right edge of the manometer even with the edge of the panel. Bore 1/4-
inch-diameter holes for manometer lines through the panel, and connect the lines
to pitot leads and the solenoid valve block. Install the leveling device as shown in
Figure 6. Secure the panel to the panel supports with 3/4-inch wood screws
through the aluminum frame. Mark the controls for quick identification to avoid
errors in switching. Attach the aluminum angle to the front cover, as shown in
Figure 1. The instrument is now ready for painting and calibration.
OPTIONAL SOLENOID VALVE ASSEMBLY
The purpose of this device is to allow the meter box operator to zero the
manometer more conveniently while the test is running. The cost of the unit is
around $50; it is not, however, essential to the operation of the sampler.
The solenoid valve assembly should be installed as shown in Figure 7.
Three two-way solenoid valves are used in this assembly; two are usually open,
and one is usually closed. One of the open solenoid valves, followed by a closed
solenoid valve, is located on the upstream tap and an open solenoid valve on
i.! .- do-"~-"»tream tap. WTien these valves are energized by closing the switch, the
flow ^ blocked ir^y the manometer and the usually closed solenoid valve opens to
allow the pressure to equalize and bring the manometer to zero. If leveling must
be done during the test, the Tygon tubing can be temporarily disconnected from
the manometer taps to manually rezero the manometer.
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Table 1. MATERIALS FOR METER BOX CONSTRUCTION
Component size,
in.
Number of
pieces
Dimensions, in.
Placement
1/2 plywood
1/2 plywood
3/8 plywood
1/4 plywood
1/4 plywood
1/4 Masoni te
3/4 pine
3/4 pine
1/8 Plexiglas
1 by 1 aluminum angle
1 by 1 aluminum angle
1
1
2
1
1
1
2
]
2
2
2
12-1/4 by 12-1/2
12-1/2 by 13
12-1/2 by 23-1/2
12-1/2 by 23-3/8
13-1/4 by 23-3/8
12-1/2 by 22-3/4
3/4 by 22-1/2
3/4 by 12-1/2
2-1/2 diameter
13-1/2
13
Bottom
Top
Sides
Back
Front
Panel
Panel supports
Panel support
Thermometer windows
Base frame, width
Base frame, depth
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ORIFICE HOLE
MADE AFTER ORIFICE
INSTALLATION
1/8 PLEXIGLAS
DHOLES MADE AFTER
INSTALLATION OF METER
J 3-1/4
\
\
^C
1
LEFT
SIDE
r
M 4-*^
"((I
i
r*
i
BACK
1 2-1/4
1
« — ij.i -j — „
.
BOTTOM
PANEL
RIGHT
SIDE
o
L. 1 1.1 fA J
r- .- .., „
T
1
1
1
I
1
i
1
1
1
1
FRONT
!
s
ALUMINUM
FRAME
i.
4
1/4
J
\
•
ALUMINUM .
FRAME
f \
t
DIMENSIONS IN INCHES
Figure 1. Meier box case construction diagram.
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• 3-3/4-
1/2 j
"T*
i. T 0
1/4 HOLES
Jt__#
2.1 /2
COOLING
MOLES
DIMENSIONS IN INCHES
5/16 HOLE
2-1/4
i
_L
Figure 2. Meter box casa bottom construction diagram.
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12-1/2-
4
j
j
j
i
1-1/2 I T
I
1 |
1 7-1 -"2
: ,
_ i
&
— I'm.
— —f. — ;
-ii.-./ii.-
^_/ "*
,.3/4 fey j d
*4-2.i.-i*i '^x,^
*~" 1 i *"
: ' 1
1 ! i
I
• 1*4
->. ~^ <«i •
\-^
.£_t
^u
y f 1--./4
•v, i
*
I * c
i i
)T
2-i /:
A
.
i
i
1
2-3/4 ;
! i
I, !
lT \
22-1 /2
1 3-3/4 !
]
i
j
| j
! i
.
i i
OLZ OIAMETERCODE
3/4 n/16 1/2 7/1* DIMENSIONS IN INCHES
® 0 • ®
Figure 3. Meter box panel hole pattern diagram.
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Table 2. PLUMBING PARTS LIST FOR METER BOX
Part
Description and/or catalog number
1 pump
1 oiler
] muffler
) vacuum gauge
1 gas meter
1 manometer
1 va1ve, need 1e
1 va1ve, ball
1 quick disconnect
2 quick disconnects
3 male elbows
1 male connector
3 adaptors
1 adaptor
1 adaptor
4 ells
2 tees
1 tee
3 nipples
1 adaptor
1 union
3-ft tubing
3-ft tubing
1 ell
2 connectors
4 inserts
1 roll tape
2 ferrules
2 ferrules
6-ft tubing
2 thermometers
Sast 522-V3
Gast, modified wick oiler
Cast glass jar, modified
Gast, 0-30 in.
Rockwell N-68 S 175S 175CFH direct readout, 1 x 10 ft
Dwyer No. 422010, inclined vertical manometer
Whitey 1 RF 4-A
Hoke 30201-5
Swagelok 810-1/2 in. QC-6100, bulkhead
Swage1 ok 400-1/2 in. QC-6100, bulkhead
Swagelok 600-2-4
Swagelok 400-1-2
1/4-in, male pipe to 3/8-in. sweat, copper
1/4-in. male pipe to 1/4-in. sweat, copper
1/4-in. female pipe to 3/8-in. sweat, copper
3/8-in. sweat, copper
3/8-in. sweat, copper
1/4-in. pipe, copper
1/4-in. pipe, close, copper
1/4-in. male pipe to 1/8-in. male pipe, copper
3/8-in. sweat, copper
3/8-in. hard copper
1/4-in. soft copper
1/4-in. sweat, copper
1/8-in. tubing to 1/16-in. butt-weld Swagelok 200-1-2W
1/4-in.-OD tubing; 1/8-in.-iO Swageiok 405-2
"Strip Teeze" Swagelok, Teflon
Swagelok 203-1, Teflon
Swagelok 204-1, Teflon
1/4-in.-00 by 1/8-in.-ID Tygon
Weston Model 2261 - 40" to 160° F
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MATERIAL: STANDARD HARD COPPER TUBING
EXCEPT FOR BRASS ORIFICE DISK,
ALL FITTINGS SWEAT SOLDERED.
DIMENSIONS IN INCHES
ORIFICE
I/2-OO BRASS WASHER
DRILLED OUT TO 3/H-l O
Figure 4. Orifice construction diagram.
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Table 3. ELECTRICAL PARTS LIST FOR METER BOXa
Part
Part number and/or manufacturer
Cost, S
1 ma 1e plug
4 SPOT toggle switches
1 SPOT toggle switch
6 pi lot 1ights
1 Amphenol connector
1 Amphenol cable clamp
I variable transformer
1 re I ay
1 interval timer
1 gear rack assembly
1 cooling fan
3 solenoid valves
30-ft, 16-gauge stranded
hookup wI re
Eagle parallel ground-rubber-handle cap, $ 0.45
15 A B 125 V
Allied 26A37I7
Standard duty 115-V, 15-amp solder 0.57
term!nals
Allied 56A4534
Standard duty 115-V, I5-amp solder 0.66
term!nals
Allied S6A4536
Snaplite neon lights (pilot), series 32 0.75
Allied 60A7922
Series 3i06A, 145-25 1.26
3057-^ 0.57
Powerstat, No. 10B 8,50
Allied 54E2536
Potter and Blumfield 8U-120 AC 1.85
Industrial timer CM-5 foundation unit 18.75
Allied
Industrial timer A-30 1.75
Allied 58E8518
Rotron 100-cfm muffin fan venturi model 14.50
Allied 60E8597
Skinner Precision Industries, iO.OO
New Brittain, Connecticut (approxi-
S 2 DA9052 115/60 mately)
VN7-308
Allied Radio Catalog Numoers are provided for reference, not as suggestion for
purchase.
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TO MANOMETER
ZERO
Figure S. Meier box wiring diagram.
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DIMENSIONS IN INCHES
TEE NUT 3/4 ID, 1/2 x 8-32
TEE NUT 5/16 - 18
MACHINE BUMPER 3/4 ID, 1/2 x 8-32
Figure€. Leveling device construction Diagram.
TO PUMP SWITCH
SPOT SWITCH
NORMALLY
OPEN I
^
4
NORMALLY
CLOSED r
-4s
1 !
•, M
NORMALLY
OPSN T
,
•* SOLENOID VALVES
TO MANOMETER
Figure 7. Optional solenoid assembly diagram.
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SAMPLE BOX CONSTRUCTION
Refer to Figures 8 and 9 for part numbers. Figure 10 is a three-dimen-
sional view of the assembled parts.
Begin construction "by cutting out the parts. Attach part number 3 to parts
B, 6, and 4; attach with screws so that part 3 can be removed for servicing the fan
and heater components. To this assembly, add bottom (part 9); attach with glue
and screws except at the joint with part 3, Using glue and small brads, attach
parts 7, 12, and 5, in that order. At this point, the impinger bath area (shaded
section on Figure 11) should be lined with fiberglass cloth and resin to provide a
water-tight compartment. Place tape on ail joints and apply at least two coats of
resin. While the fiber glass is curing, attach parts 1 and 2; add hinges for the
attachment of part 3. Also install a catch and knob to part 1. An electrical parts
list is given in Table 4, and Figure 12 shows a wiring diagram. Screw the ther-
mostat housing, Amphenol fitting, and probe socket to part 10, Form an alumi-
num shield around the heating coil, and attach it to the blower. Remove part 3,
and attach the blower and thermostat into place. Complete the wiring of the fan
and thermostat, and replace part 3. Glue Pentafoaxn insulation onto parts 6 and
12, and insert impinger support (part 11). Paint the inside of the heater compart-
ment with aluminum paint for heat reflection; also paint the exterior of the box.
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2
1
7
I
H — 4— H
k
10-1/4 »-j
3
1
U 1-1/2
2-1 X4
*"1
•* 7-1/2 ^
a
i
1
'
i
'
j
*.
4
3/4 HOLE
O
I" \
:i-i n
2
0
!
I
•* —
h-
i
10
<«
1
-« 4-1 /3 •• «>
&
- HO 4 — •*-
2-3 -'4
"
l-l.'t
10
1 -1
6-3/4 ~*4
1
•*. 7
Ll
-4
i -i
E
A
, H!
i
*-l/2
(/2 I
•[
O
u.
<
z
a
/-~
/ ,
V '
v_
/
( -
V.
I IB
- )
^
•«• — • - - J-l/7 »•
MATERIALS
3/8-EXTERIOR PLYWOOD
1 PC. 6x7 NO. 2
\ PC. 10-1/4 x 13 NO. 3
JO 1 fO. 1 I-l/ii X IJ NU. 1
1 PC. 6-3/4 x 20 NO. 6
1 PC. 11-3/4 x 20 NO. 8
1 PC. 3-1/2 x 9 NO, 10
DIMENSIONS IN INCHES
(drawings not lo scale)
Figure 8. Sample box construction d(a" m, plywood parls.
-------
1
•« 6-1/7
7
,
*1
1
t
7-1/4
1
3
12
B
2
'
p* 6-1/2 M
-H
« — i ~ - •*•
1
4-3/4
t
9
!
i
i
1/2 THICK
PENTAFOAM
DIMENSIONS IN INCHES
MATERIALS:
1/8 TEMPERED MASONITE
1 PC. 6-1/2 x 7-1/4 NO. 1
1 PC. 10 x 11-1/4 NO. 5
1 PC. 4-l/2x 13 NO. 7
1 PC. 11-1/4 x 12 NO. 9
1 PC. 6-1/2 x 20 NO. 12
Figure 9. Sample box construction diagram, Masonite and Penta(oam parts.
-------
Figure 10, Three-dimensional view of sample box.
-------
T?
W w\ x x x x x x x.
\^/^^
O
O
1
K N
|\ N
K N
R ^
^ ^
IN ^
*N "S
j\ \
O
\
\ \
\ N
x N
s N
S \
N N
X X
X N
X s
• T- \ N \ x N N Ni N "^ v \
Figure 11, impinger bath irea. (Shaded area
reinforced-with fiber glass.)
Table k. ELECTRICAL PARTS LIST FOR SAMPLE BOX
Part
Part number and/or manufacturer
Approximate
cost, $
Ampheno! connector
Amoheno! cable clamp
Thermostat
Blower
Heating element
Base, 2-piece porcelain
Socket
Series 310A, l^5-2P
3057-6
White Rodgers, St. Louis 23, Mo.
1002-6 Temperature Control
Dayton (1) 2C782
Dayton Electric Mfg. Company
Chicago, 111.
Eagle Electric Mfg. Company
Long Island City, N. Y.
Eagle Electric Mfg. Company
Long Island City, H. Y.
Ampheno 1 160-2
Allied No.
0.57
20.00
15-20
1.50
2.00
0.93
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HEATER
THERMOSTAT
o
o
PROBE
AMPHENOL CONNECTOR
Figure 12. Sample box wiring diagram.
20
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UMBILICAL CORD CONSTRUCTION
Table 5 is a parts list for umbilical cord construction. The umbilical cord
may be made in any length up to 200 feet •without encountering a prohibitive pres-
sure drop; for convenience, however, it is preferable to make a number of cords,
each 25 feet long. Figure 13 shows construction details for the umbilical cord.
The cord is fabricated by cutting 25-foot lengths of the components—vacuum hose,
electric wires, and pitot tubing—and laying them together in a clear working area.
Starting 2 feet from one end, wrap the components together with a suitable tape
such as "Mystic" cloth tape or plastic electrical tape. Wrap the cord up to 2 feet
from the other end. Orient the ends of the cord by specifying one a meter end and
the other a. sample end; the meter end should be plugged into the meter box, and
the sample end should be attached to the sample box.
At the meter end of the vacuum hose, attach a 1/2-inch male quick disconnect
by screwing the thread of the 1/4-inch pipe into the hose. Attach the two male
1/4-inch quick disconnects to the pitot lines and solder the electric cords into the
male Amphenol connector. On the sample end, attach the fittings in the same way,
using a female Amphenol fitting and quick disconnects.
21
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Table 5. PARTS LIST FOR 25-foot UMBILICAL CORD
Part
Description and/or catalog number
50-ft Tygon tubing
25-ft pressure hose
50-ft electric cord
1 roll tape
2 quick disconnects
2 quick disconnects
1 quick disconnect
1 quick disconnect
1 Amphenol connection
) Amphenol connection
2 Amphenol cable clamps
l/4-in.-OD by l/8-in.-ID
3/8-in,-ID Neoprene air hose
16-gauge zlpcord
Mystic or plastic electrical
}/k F 400 - 1/4 QC - 600
1/4 M 400 - 1/4 QC - 200
1/2 F 810-1/2 QC - 100 - 4
1/2 M 810-1/2 QC - 200
Series 3106* - 145-25 (female)
Series 310IA - 145-25 (male)
3057 - 6
16-gauge ZIPCORD
PLASTIC TAPE'
1/4-OO x 1/8-1D TYGON
AIR HOSE, 3/8 ID
400- 1/4 QC - 200
400 - 1 /4 QC - 60
MALE AMPHENOL
FEMALE AMPHENOL
\\\\\\\\\\\Y
310- 1/2 QC - 200
METER END
-a.
• 25 ft •
810- 1/2 OC -100-4
SAMPLE END
DIMENSIONS IN INCHES UNLESS OTHERWISE INDICATED
Figure 13. Umbilical cord construction diagram.
22
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PITOBE CONSTRUCTION
Refer to Table 6 for the parts necessary for pitobe construction. Pitches of
any length from 2 to 10 feet may be used without encountering problems during
sampling. The first step is to cut the sheath to the desired length and weld a
Swagelok 5/8-inch ferrule nut onto one end of the tube. The nut must be square
with the end of the tube. The use of a pilot shaft as shown in Figure 14 will ensure
that it is square. Welding may be done with silver solder if the probe will not be
used in stacks where the temperature exceeds 1, 000° F; if higher temperatures
will be encountered, arc welding will be necessary. On the opposite end of the
sheath, cut a notch to clear the electric wire for the probe heat as shown in the
figure.
PITOT
The pitot is made by bending a 45-degree angle on the end of a 3/8-inch
stainless steel tube and cutting as shown in Figure 14. After two of these have
been cut, they are welded together with the cut ends facing in opposite directions
and in as good alignment as possible. The welds should be about 1 foot apart along
the length of the pitot. The pitot should be 2 inches shorter than the sheath, and
the last weld should not be closer than 6 inches from the end, as shown in Figure
14. Bend out the two ends slightly to facilitate attachment of quick disconnects.
When the above steps have been completed, weld the pitot to the sheath using short
pieces of 1/4-inch stainless steel. The center of the pitot opening must be 3-1/2
inches from the front of the sheath nut so that the pitot and nozzle will be adjacent
during sampling. To determine the length relationship of the various parts, let
L ~ length of the probe sheath with the nut welded on; then the length of the pitot
tube without the quick disconnects will be L minus 2 inches, and the length of the
glass probe will be L plus 2 inches.
PROBE GLASS
The glass insert length must be determined before the ball joint is attached.
The latter usually must be custom-made by a glassblower. After the ball joint
is attached, a No. 7 rubber stopper, bored as shown in Figure 14, is slipped onto
the glass tube. After the stopper is in place, a 25-foot Nichrome wire is logarith-
mically wound onto the glass and held in place with glass electrical tape, Th«
23
-------
wire is doubled, and the winding is begun about 2 inches from the end and continued
along the length of the probe. As each few inches is wound, a piece of tape is put
on to hold the wire as the winding is continued. After the entire probe has been
wound with wire, it is then rewound with the glass tape. The remaining two ends
of the Nichrorne wire are soldered to the zipeord, which plugs into the sample
box.
Table 6, P1TQBE PARTS LIST
Part
1 un i on
25-ft wlre
2 male quick disconnects
I rubber stopper
J ball joint
2-ft electrical cord
1 plug
1 ro!1 tape
2-ft pi tot tubing*
1-ft glass tubea
1-ft probe sneath3
Description
Swage 1ok 1010-6
Nichrome 26 B & S Curt in 22870 F
Swage 1 ok 400-1A SIC-200
No. 7
Groynd glass No. 28
16-gauge 2-conductor zipeord
Male, 2-prong
Scotch electrical No. 27 - ^EGT - G?8%T
3/8-tn.-QD thin-wall stainless steel
5/8-in,-00 Pyrex
l-tn.-OO by 0.035 wall MIL-T-8504
Seamless Summer!1 AWTR 304
Per foot of pitobe.
24
-------
INJ
in
CUT
HERE
WELD EACH FOOT
K NUT
_
C
i _ o
3 C
L,
3 C
~^Cx
3
t OD x 0.035 WALL STAINLESS STEEL TUBE j~
WELD
5/8 PILOT SHAFT
2*
(minimum)
O.§30
L*2
\ \ \ \ \\ \ m\\m\v^\\\\ \\ \\ \\
GLASS TAPE \ \ NICHROME WIRE
WELD
END VIEW
OF ASSEMBLY
NO. 7 STOPPER
H
NO. § 28/12
BALLJOINT
IB-gauge ZIPCORD
DIMENSIONS IN INCHES
Figure 14. Pi lobe construction diagram.
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GLASSWARE
Refer to Table 7 for the glassware parts list. The probe is connected
directly to a cyclone that has been modified by the addition of No. 23/15 ground-
glass ball joints. The cyclone, built as shown in Figure 15, is attached to a
modified filter holder (Figure 16) that has also been fitted with ball joints. The
filter holder is held together with a clamp that is fabricated from 1/8-inch alumi-
num. This filter holder contains a glass frit and also has a silicone rubber gasket,
which can be made by most gasket companies.
From the filter, a ball-joint-fitted connector leads into the first irnpinger.
A set of three connectors then leads through the three remaining impingers.
Refer to Table 8 for the irnpinger connector parts list. These impingers also
have been modified by the addition of ball joints. The last impinger is attached to
an umbilical cord connector that contains a check valve to prevent backpressure
from pulling the impinger liquids into the filter. All of this glass modification
should be done by a competent glassblower. If the sampling situation does not
require the use of a cyclone, then a bypass fitting can be used.
Table 7. GLASSWARE PARTS LIST
Part
Description
Cyclone
Filter
Impinger
Connectors
Ball joints
Socket
C1 amps
Specially fabricated as shown in Figure 15
Fabricated
6800 - Corning
Fabricated from ball joint and l/2-in.-ID glass tubing
Corning No. 6762 ball 28/12
Corning No. 6764 socket 28/12
Ball and socket joint clamp size No. 28
27
-------
rs>
CO
5/8 ID
MATERIAL: PYHEX GLASS
COST: ABOUT $40
DIMENSIONS IN INCHES
Figure 15. Source sampling cyclone.
-------
MATERIAL: PYREX GLASS
SILICONS RUBBER
GASKET
28/15 3ALL SOCKET
• 3-1/8 -
2-7/8
28/12 BALL JOINT
FRITTED GLASS DISK
DIMENSIONS IN INCHES
Figure 16. Sectional view of filter holder.
Table 8. PARTS LIST FOR IMPINGER CONNECTOR
Part
Description
Ball joint
Check valve
Quick disconnect
Tube
Hose
Connector
Thermometer
Female, stainless steel
NUPRO 8-C 1/2-in, tubing
Swage 1ok, 810-1/2-in. QC-600
3/8-in.-stainless steel, 3 in. long
3/8-i n.-10 Neoprene a i r hose
Swage 1 ok 200-1-2W, 1/8-in.
tubing to butt weld
Weston dial Model 2292 25 - 125° F
29
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CALIBRATION PROCEDURES FOR ORIFICE AND METER
A preliminary check should be made of the following parts for proper opera-
tion before trial test: pump, pump oil, quick disconnects, valves, manometers,
dry test meter, thermometers, lights, buzzer, Amphenol, Variac, and vacuum
gauge. Vacuum should be tested for leakage at 27 inches.
TERMINOLOGY
cfm = ft^ /min
AHg = Orifice pressure differential in inches of water that gives 0, 75
cfm of air at 70° F and 29. 92 in. Hg
Y = Dry meter differential, in. H2O
Pb - Barometric pressure, in. Hg
CFW = Wet test meter reading, ft3
CF
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If the value is not within 1. 6 to 2,1 (I. 84 desired), the orifice can be drilled in
increments of 1/64 inch, to lower the value; if the value is below 1.6, then the
orifice should be replaced and the procedure repeated in calibration.
2
Calculate Y by us ing the formula
y -
CFd(Pb * 0. 147) (Tw + 460)
Y is obtained during the trial run along with AHg. If the value is not within 0. 99
and 1. 01 (1. 00 desired), adjustments have to be made to the meter. To adjust the
meter, remove the four screws on the top of the meter, carefully remove the lid,
and expose the lever mechanism to make sure that the adjusting nuts "A" and "B"
ire in position. To adjust the meter, "A" and "B" are turned clockwise to
lecrease the value of Y and counterclockwise to increase the value of Y. After
naking the adjustment, replace the lid and screws and run another trial test.
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