570987003
TECHNICAL ASSISTANCE DOCUMENT:
THE APPLICATION AND CALIBRATION OF
PRESSURE INSTRUMENTS, FLOWMETERS, AND
FLOW CONTROL DEVICES AS APPLIED
TO INJECTION WELLS
Prepared by:
The Underground Injection Control
Quality Assurance (UIC-QA) Workgroup,
U.S. Environmental Protection Agency
Office of Drinking Water, State Programs Division
Underground Injection Control Branch*
Project Manager:
Mario Salazar
State Programs Division
ODW (WH-550E)
EPA Headquarters
401.M Street, S.W.
Washington, D.C. 20460
Final Technical Editing:
Drew Dawn Enterprises, Inc.
2522 South Dakota Avenue, N.E.
Washington, D.C. 20018-1634
(202) 526-3577
September 1987
*See Acknowledgements
-------
DISCLAIMER
This report was prepared for informational training
and technical assistance purposes. Any references to
specific companies, trade names, or commercial products
do not constitute endorsements or recommendations of
them by the United States Environmental Protection
Agency.
-------
ACKNOWLEDGEMENTS
The preliminary drafts of this document were prepared by
Mr. Anthony J. Vellios and Mr. John Mentz of SMC Martin
Inc., Valley Forge, Pennsylvania under EPA Contract No. 68-
01-6288. The manual was extensively revised and completed by
the UIC-QA work group. The authors acknowledge the valuable
input provided by Mr. Jeff Cantwell of 3D Instruments and Mr.
Jim Casey of Waco Associates. Special mention is given to
Mr. Joe Roesler of EPA EMSL-Cincinnati as the principal re-
viewer and contributor in his role as instrumentation expert.
The UIC-QA work group members were:
Philip Baca*
New Mexico Oil Conservation Division
P.O. Box 2088
Santa Fe, NM 87501
Gene Coker . (404) 347-3866
U.S. EPA Region IV, GWS, WSB
345 Courtland Street, NE
Atlanta, GA 30365
John Creech*
Dupont Company
Box 3269
Beaumont, TX 77704
Richard Ginn*
. Railroad Commission of Texas
P.O. Drawer 12967
Capital Station
Austin, TX 78711
Fred Hille (601) 961-5171
Bureau of Pollution Control
Mississippi Department of Natural Resources
P.O. Box 10385
Jackson, MS 39209
Juanita Hillman (303) 236-5065
U.S. EPA Region VIII, 8ES
One Denver Place
999 18th Street.
Denver, CO 80295
Linda Kirkland (214) 655-2217
U.S. EPA Region VI, Office of
Quality Assurance
' 1445 Ross Avenue
.Dallas, TX 75202-2733
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ACKNOWLEDGEMENTS
(continued)
Charles A. Koch (701) 224-2969
North Dakota Industrial Com.
900 East Blvd.
Bismarck, ND 58505 .
Bert Moniz*
Dupont Company
Box 3269
Beaumont, TX 77704
Bernie Orenstein*
U.S. EPA Region V, 5WD
230 South Dearborn Street
Chicago, IL 60604
Paul Osborne*
U.S. EPA Region VIII, Water Division,
8WM-DW
1860 Lincoln Street
Denver, CO 80295
Irwin Pomerantz*
U.S. EPA Headquarters
QAO, Office of Drinking Water (WH-550)
401 M Street, S.W.
Washington, B.C. 20460
Joseph Roesler** (513) 569-7286
U.S. EPA, EMSL
26 W. St. Clair
Cincinnati, OH 45268
Mario Salazar (Project Manager) (202) 382-5561
U.S. EPA Headquarters
401 M Street, S.W.
Washington, D.C. 20460
Jeff van Ee (702) 798-2367
U.S. EPA, EMSL-LV, AMD, AMW
P.O. BOX 15027
Las Vegas, NV 89114
Ron Van Wyk (Task Leader)** (214) 655-7160
U.S. EPA Region VI, WSB (6W-SG)
1445 Ross Avenue
Dallas, TX 75202-2733
* No longer in work group
**Mainly responsible for the manual
iii
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PREFACE
Correctly selected, accurately installed, and properly
functioning flowmeters and pressure gauges are essential to
precisely monitor injection wells. The type of device se-
lected must be suitable for the accuracy and precision re-
quired of the measurement. The construction material of the
instrument must be compatible with the environment in which
the meter or gauge is placed; it must be appropriate also for
. . .* ,
the pressures, temperatures, fluid properties, and flow
ranges that are anticipated. Moreover, measurement control
devices should always be properly maintained and calibrated;
the manufacturers' specifications and guidelines should
be followed, and their factory services used, when appro-
priate .
The best way to maintain the proper functioning of a
gauge or meter is to regularly clean and calibrate it. The
time limits between recalibrations depend upon the type of .
instruments, and type of fluids to be measured. Gauges and
meters can be recalibrated on site by the owner, if the right
equipment is available; and, if it is not, done off site by
either a service shop or the manufacturer.
Finally, this document was prepared to introduce the
basic concepts of flow and pressure metering in injection
wells to EPA Regional office staffers, state regulators, and
the regulated community.
The reader will find manufacturer's lists, and inspec-
tion and operator checklists at the end of the manual.
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TABLE OF CONTENTS
Page
PREFACE iv
LIST OF FIGURES vi
LIST OF TABLES . ' viii
INTRODUCTION 1
PRESSURE MEASURING DEVICES 3
Pressure Gauges 3
Bourdon Tubes 3
Helical Coil Gauges 10
Gauges and Extreme Environments 10
Pressure Transducers • 15
Downhole Pressure Recording Devices 17
Pressure Recording Devices " 20
Methods for Testing Pressure Instruments 23
Deadweight Tester 23
Portable Gauge Testers 24
Calibrating Pressure Gauges 28
"Negative" Pressure Gauges 31
Open Annulus Wells 32
FLOWMETERS 33
Types of Flowmeters . 33
Operational Principles 38
Positive-Displacement Flowmeters 38
. Turbine Flowmeters 44
Differential 'Pressure-Producing Flowmeters 49
Sonic Flowmeters • -55
Doppler Flowmeters 57
Float-Type Flowmeters '59
Electromagnetic Flowmeters 61
Vortex-Shedding Flowmeters , 63
Other Flowmeter Designs 63
Testing and Calibrating Flowmeters 65
Flow Recording Devices 68
CONTROL DEVICES 69
Valves .71
Actuators 78
APPENDIX A - List of Manufacturers 79
APPENDIX B - Glossary 82
APPENDIX C - Publications 85
REFERENCES 88
CHECKLISTS FOR INSPECTIONS 89
v
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LIST OF FIGURES
Figure Title Page
1 The Working Components of the Bourdon
Tube Driven Pressure Gauge '4
2 • Retarded Gauge • 11
3 Retard Spring and Clamp ' .11
4 Helical Coil Gauge ' 12 .
5 Diaphragm Seal • . 14
6 The Pressure Transducer (bottom) and
the Wheatstone Bridge Strain Gauge
(top) 16
7 The Amerada RPB-4-Gauge 18
8 Electronic Receiver-Recorder 21
9 Mechanical Pressure Recorder . 22
10 Deadweight Tester and Portable Gauge
Tester 25
11 Portable Gauge Tester 27
12 Bourdon Gauge Components 29
13 Bi-Rotor Oval Gear Meter 39
14 Rotating-Paddle Meter 40
15 Oscillating Piston Meter 41
16 Rotating Vane Meter ,42
17 Major Components of a Turbine Meter 45
18 Bearingless Flowmeter 47
19 Flow Ranges and K-Factors 48
20 Typical Turbine Performance Curve 48
21 Schematic Diagram of a Working Orifice 50
22 Schematic Diagram of a Working Flow
Nozzle 51
VI
-------
LIST OF FIGURES
(continued)
Figure Title . . Page
23 Plan View of a Flow Tube 52
24 Plan View of a Venturi Tube 53
25 Sonic Flowmeter , 56
26 Doppler Flowmeter ,58
27 Typical Transparent Float Flowmeter 60
28 Principles of Magnetic Flowmeters 62
29 Cut-Away View of a Vortex-Shedding
Flowmeter 64
30 Schematic Diagram of a Piston Prover 67
31 Block Diagram of the Working Compo-
nents of an Electronic Recorder 70
32 The Eccentric Plug Valve : 74
33 Globe Control Valve 75
34 Cage Plug 77
VII
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Table
LIST OF TABLES
Title Page
1 Fluid Media and Appropriate Bourdon
Tube Material 6
2 Different Flowmeter Specifications 34
3 Flowmeter Material Resistance 36
4 Applications of Various Valve Designs 72
Vlll
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INTRODUCTION
The Underground Injection Control (UIC) program was
established by the U.S. Environmental Protection Agency to
protect underground sources of drinking water (USDWs) from
potential pollution by injection wells. Improperly completed
or operated wells can cause ground water contamination.
The UIC program requires that the mechanical integrity
of. all injection wells be tested before operation begins, and
at least once every five years thereafter. For Class I wells
the annulus pressures, injection pressures, flow rates and
volumes must also be continuously monitored and recorded.
Periodic, monitoring of pressures and flow rates is required
for Class II and III wells.
Except during well stimulation, injection pressures must
not exceed a magnitude which would initiate fractures or
propagate existing fractures in confining beds adjacent to
USDWs (in regards to Class II wells), or the injection zone
in the case of Class. I and III wells.
An important part of the Underground Injection Control
program involves monitoring injection volumes and rates, and
injection and annulus pressures. This observance requires
the availability of accurate and reliable equipment, along
with the knowledge needed for proper application.
Flowmeters, indicators, and recorders are used to measure and
record volumes and injection rates; the pressures are
ascertained with gauges, transducers, and/or various downhole
-------
instruments.
Each instrument has its own operating requirements,
which must be met to assure that the device operates within
specifications. Excessive temperatures, pressures, flows, or
vibrations will generally adversely affect the accuracy and
service life of these instruments; care must, therefore, be
taken to install and maintain these devices according to the
manufacturer's instructions. :
Devices that measure pressures and flows often have to
be calibrated before installation and recalibrated
periodically to assure continued accuracy. It is the
operator's responsibility to assure that tests and
recalibrations are conducted as required. Inaccurate
instruments should be recalibrated, repaired, or replaced as
quickly as feasible.
' This report discusses the various devices that are used
to measure the pressures and the flow rates of injection
wells; particularly, those instruments that are used by
regulatory agencies and injection well operators for
assessing well operations.
Some terms are used in this report that may be
unfamiliar to the reader; these expressions are defined in
Appendix B.
Check Lists are included at the end of the document
which can be used by appropriate personnel to determine the
effectiveness of flow control devices as applied to
underground injection control programs.
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PRESSURE MEASURING DEVICES
Injection pressures are measured in several ways. One
procedure uses the pressure source to mechanically expand a
hollow tube or a coil which in turn causes a pointer to move
across a graduated dial; this method utilizes several kinds
of pressure gauges as well as downhole pressure "bombs," and
self-contained pressure recorders. Another uses pressure
transducers that contain a strain gauge that is connected to
an exposed diaphragm. As the diaphragm stretches under
pressure, its strain is converted into an electrical signal
V
that is proportional to pressure. Both pressure transducers
and pressure gauges are discussed in detail in the following
pages:
PRESSURE GAUGES
The standard pressure gauge is a small instrument (1"-6"
diameter) and consists of a dial face, a pointer, and a
driving mechanism. It is connected directly to the pipe in
which pressure is to be monitored. Pressure can be instantly
read on the dial face. Most such gauges are inexpensive and
compact — if compared to other measuring devices.
Bourdon Tubes
Most pressure gauges use the Bourdon "C" tube as the
driving mechanism for the gauge pointer. The Bourdon tube is
a hollow C-shaped tube as shown in Figure 1. The tube is
located inside the gauge case and is directly attached to a
-------
Figure 1. The Working Components of the Bourdon Tube
Driven Pressure Gauge. The fluid under
pressure flows directly into the tube and
causes it to expand. This expansion pulls
a segment gear which in_turn drives a
pointer.
POINTER
BOURDON
TUBE
BOURDON TUBE WITH
INTERNAL PRESSURE
GAUGE RIM
SEGMENT GEAR
STEM
PRESSURIZED FLUID
-------
threaded stem. The fluid travels through the stem into the
tube. The tube deflects in proportion to the amount of fluid
pressure. This in turn forces a segmented gear arm to drive
the pointer gear. The gearing can be slightly adjusted to
assure linearity and provide an accurate pressure reading.
The tube can be made from a variety of materials, but
construction materials must be selected so as to protect the
instrument from corrosion, since the fluid is in contact with
the inside of the tube. Table 1 gives the appropriate
materials to be used for different fluid media. Bourdon tube
gauges can be designed to measure pressures up to 20,000 psi.
Inaccuracies range from 0.25 percent to 3 percent of full
range. (Temperature is an important factor to be considered
in reducing error.)
The error expected can be approximated by the formula:
e = .02 x T x P
Ps
In which:
.02 = an empirical constant
e = error
T = Temperature (°K)
P = Pressure, applied
Ps = Pressure range
(Considine, 1974)
-------
TABLE 1
FLUID MEDIA AND APPROPRIATE BOURDON TUBE MATERIAL
LEGEND
P
S403
M
S316
Bourdon Tube Material
Phosphor Bronze
403 Stainless Steel
K Monel
316 Stainless Steel
Medium
Acetone
Acetic Acid
Acetate Solvents
Acetic Anhydride
Acetylene (dry)
Alcohols
Alums
Ammonia
Ammonium Carbonate
Ammonium Chloride
Ammonium Hydroxide
Ammonium Phosphate
Ammonium Sulfate
Aluminum Chloride
Aluminum Fluoride*
Aluminum Sulfate
Amyl Chloride (dry)
Beer
Benzene
Benzol
Boric Acid
Benzyl Alcohol
Brine*
Bourdon Tube Material
P, S403, M, S316
S316, S403
S403, M, S316
M, S316
P, S403, M, S316
P, S403, M, S316
S403, M, S316
S403, S316
S403, S316
M
S403, S316
S403, S316
M - .
M
M
S403, M, S316
M
P, M, S316
P, S403, M, S316
P, S403, M, S316
P, M •
S403, M, S316
M
Medium
Bromine (dry)
Butane
Butanol
Butyric Acid
Calcium Chloride*
Calcium Bisulfite
Calcium Hydroxide
Carbon Dioxide (dry)
Carbon Disulfide
Carbon Tetrachloride
(dry)
Carbonic Acid
Carbolic Acid
Chlorine (dry)
Casein
Chloroform (dry)
Chromic Acid
Chromium Fluoride* .
Citric Acid
Coal Gas
Cottonseed Oil
Copper Sulfate
Cuprous Oxide
Ethers
Bourdon Tube Material
M
S403, M, S316
P, M :
P '
P, S403, S316
S403, S316
P
P, S403, M, S316
S403, S316
M, S316
M, S316
M, S316
M, S316, S403
P
P, M, S316
S403, S316
M
S403, M, S316
P
S403, M, S316
S403, S316
S403, M, S316
P, S403, M, S316
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TABLE 1
(continued)
Medium
Ethyl Cellulose
Ethyl Acetate
Ethylene (dry)
Ethyl Chloride (dry)
Ethylene Dibromide
(dry)
Ethylene Bichloride
(dry)
Ethylene Glycol
Ferric Nitrate
Ferric Sulfate
Formaldehyde
Freon
Gasoline
Gelatine
Glucose
Glycerine
Hydrocyanic Acid
Hydrogen
Hydrogen Peroxide*
Hydrogen Sulfide
Kerosene
Lacquers
Lactic Acid;
Lithium Chloride*
Magnesium Chloride*
Magnesium Sulfate
Naptha
Mercury
Natural Gas
Bourdon Tube Material
P, S403, M, S316
P, S403, M, S316
M
M
P, M
M
P, S403, M, S316
S403, S316
S403, S316
M, S316
P, S403, M, S316
P,..S403, M, S316
M, S316
P, S403, M, S316
P, S403, M, S316
S403, M, S316
P. M, S316
S403, M, S316
M -
P, S403, M, S316
P, S403, M, S316
S403, S316
M .
M
P, S403, M, S316
P, S403, M, S316
S403, S316
P, S403, M, S316
Medium
Magnesium Hydroxide
Nickel Acetate
Nitrogen
Nitric Acid*
Nitrous Acid*
Nitrosyl Chloride
Oleic Acid
Oxalic Acid
Oxygen*
Paraffin
Picric Acid •
Phosphoric Acid*
Phosphorous Acid*
Photographic Solutions
Petroleum Oils
Potassium Chloride*
Potassium Hydroxide
Potassium Sulfate*
Potassium Permanganate
Propane Gas
Pyroxylin
Salicylic Acid
Steam (under 300 psi)
Steam (over 300 psi)
Sodium Bicarbonate
Sodium Bisulfate
Sodium Carbonate
Sodium Chloride*
Bourdon Tube Material
S403, M, S316
P, M
P, S403, M, S316
S316
S316
M
S403, M, S316
M
P, S403, M, S316 .
P, S403, M, S316
S403, S316
S403, S316
S403, S316
S403, S316
P, S403, M, S316
M
M
M
S403, S316
P, S403, M, S316
M
P, S403, M, S316
P, S403, M, S316
S403, S316
M, S316
M, S316
M, S316
M
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TABLE 1
(continued)
Medium Bourdon Tube Material
Sodium Cyanide S403, S316
Sodium Fluoride* M
Sodium Hydroxide* M, S316
Sodium Metaphosphate M, S316
Sodium Nitrate* S403, M, S316
Sodium Perborate* M, S316
Sodium Peroxide* S403, M, S316
Sodium Phosphate S403, M, S316
Sodium Silicate S403, M, S316
Sodium Sulfate* M
Sodium Sulfide S403, M, S316
Sodium Sulf ite* M, S316
Silver Nitrate S403, S316
Stearic Acid S403, M, S316
Sulfur Dioxide* S403, S316
Sulfurous Acid* S403, S316
Tetraethyl Lead M
Titanium Sulfate M
Toluene p, S403, M, S316
Trichloroethylene S403, M, S316
(dry)
* Depending upon certain conditions
(Chilton, 1976)
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The gauges used for injection well monitoring should
have a full scale pressure range not more than twice that of
the normal injection pressure (Chilton, 1976), otherwise the
sensitivity of the meter to measure accurately is lost. For
example, a Bourdon gauge installed on a well where normal op-
erating pressure is. 1000 psi should have a full range of not
more than 2000 psi. If a 10,000 psi is used, the maximum er-
ror would increase from 60 to 300 psi (140 to 700 feet of
head).
One advantage of Bourdon gauges is that their movements
can be retarded. The scale of a retarded gauge abruptly
changes at a certain point on the dial (see Figure 2). Often
these gauges have a small portion of the total scale reading
spread out over 90 percent of the dial. This allows a gauge
reader to.observe a normal range of pressures, while provid-
ing a means to read pressures far above normal. Retarding is
achieved by attaching, a spring to the gauge movement (see
Figure 3) and allowing the segment gear to come in contact
with the spring only at the required pressure range.
A disadvantage of the Bourdon tube pressure gauge is its
inability to handle vibrations without special equipment.
Pulsating pressure or vibrating pipelines•can cause gear
teeth and bearing wear; powder from these abraded parts can
deposit on other moving parts of the gauge which can result
in loss of calibration and operational life..
• There are several methods to diminish the harmful ef-
fects of vibration. One is to connect pulsation dampeners
-------
to the stem of the gauge. For these mechanisms to work
correctly, the tube must be filled with glycerin. The glyce-
rin slows the action of the Bourdon tube and reduces the
effect of vibration.
One dampener design is a synthetic rubber bulb that
seals the service medium from the gauge proper; another uses
a moving pin, which works like a piston> to absorb most of
the vibration energy. For permanently encased gauges the
casing should be filled with glycerin or silicone to directly
dampen gear movement (Dresser-Ashcroft, Bulletin OH-1).
Helical Coil Gauges
Pressure can also be measured mechanically with a heli-
cal coil gauge (see Figure 4). These gauges use sensing
coils instead of tubes to move a pointer across a dial. The
pipe fluid is directly connected to the coil which unwinds
under pressure.
Bearings steady the coil and force the lateral movement
to translate into rotation. The degree of unwinding is di-
rectly proportional to pressure.
Helical coil gauges are especially suited for high vi-
bration applications, since they have few parts and no gears.
Some coil gauges can measure pressures as high as 20,000 psi
with errors that range only from 0.25 to 1.0 percent of full
range.
Gauges and Extreme Environments
-Some difficulties can arise with pressure gauges under
certain temperature and chemical conditions. Joint construc-
10
-------
Figure 2. Retarded Gaug.e. The scale changes at 10 psi
(Dresser-Ashcroft, 250-1353-H).
SINGLE RETARD
0 to 30 psi Dial
Figure 3.
Retard Spring and Clamp. The segment gear
swings downward with pressure and requires
more force once it strikes the spring
(Dresser-Ashcroft, 250-1353-H).
CLAMP
PILLAR SCREW
SPRING
11
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Figure 4. Helical Coil Gauge. As the pressure increases
inside the stem tube, the helical coil unwinds,
thus rotating the pointer clockwise.
POINTER.—
HELICAL
COIL
BEARINGS
GAUGE RIM
STEM
PRESSURIZED FLUID
12
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tion is an important factor in the ability of the gauge to
operate properly at a given temperature. Only gauges with
welded joints are rated to withstand a temperature of 750°F;
while silver brazed joints operate to 450°F and soft soldered
joints are rated to 150°F. Even in gauges with strong
joints, more delicate internal working parts may fail at high
temperatures. Gauges also may lose accuracy with increasing
temperatures; for example, the accuracy in- the reading of
some gauges can change 1.5 percent per 100°F. To protect
gauges from the effects of high temperatures operators usual-
ly connect the gauge to service'lines with a piece of pipe.
Tests have shown that a foot-long, half-inch pipe can reduce
a process temperature from 200°F to 120°F at the gauge where
ambient temperatures are 80°F (Dresser-Ashcroft 250-1353-H).
Pipe fluids can damage a gauge by corroding or clogging
'the measuring element (e.g., Bourdon tube) when they come in
direct contact. Diaphragm seals should be used between the
injection or annulus fluid and the gauge (see Figure 5) to
isolate the gauge from the process fluid. The pressure is
then transmitted to the gauge via the glycerin that fills the
tube and stem.
A diaphragm seal is useful when a single gauge is used
to monitor several injection systems at different times. If
a diaphragm is provided for a pipe, cross-contamination due
to switching pressure gauges is eliminated.
• Diaphragm seals are also useful to prevent extremely low
temperature fluids from entering the gauge and causing freeze
13
-------
Figure 5 .
Diaphragm Seal. The diaphragm transmits pipe
pressure to the instrument without allowing
the pipe medium to pass (ITT Hildebrandt,.
1983).
GAUGE CR
INSTRUMENT
CONNECTION
UPPER
HOUSING
LOWER
HOUSING
STAINLESS
STEEL
NAMEPLATE
FOR PRODUCT
IDENTIFICATION
CONTINUOUS
DUTY FEATURE
DIAPHRAGM
BACK-UP
RING
PROCESS
CONNECTION
14
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damage; however, a diaphragm seal can affect the precision of
a gauge and its ability to withstand pressures; such a seal
can also magnify errors created by temperature increases. A
way to remedy this is to fill the instrument with fluids that
have low thermal coefficients of expansion. Such fluids in-
clude glycerin which can be used up to 300°F and silicone
D.L. 710 which can be employed to 700°F. Since the total
error is dependent upon the fluid volume expansion, tempera-
ture change on each component, as well as the spring constant
of the diaphragm foil, the resultant accuracy can only be
estimated (Considine, 1974).
PRESSURE TRANSDUCERS
Pressure transducers convert the mechanical force of
pressure in the pipe to an electrical signal. A transducer
(see Figure 6) typically contains a pressure sensitive dia-
phragm that has four strain gauges attached to it in a con-
figuration called a Wheatstone bridge. When there is no
pressure upon the diaphragm, the bridge stays flat and the
resistance of each strain gauge is equal. The diaphragm
changes its shape as pressure is applied and this deflection
creates a change in resistance that is proportional to
pressure. When the diaphragm is exposed to pressure, the
transducer behaves like a pressure gauge.
The lack of moving parts makes the pressure transducers
ideal for employment in vibrating, corrosive, or dirty en-
vironments; they can be fitted with diaphragm seals and
dampeners for any unusual conditions. Some transducers can
15
-------
Figure 6. The Pressure Transducer (bottom) and the
Wheatstone Bridge Strain Gauge ,{top).
Pressured fluid creates a deflection on
the diaphragm which in turn changes the
resistance of the Wheatstone Bridge. The
change in current is proportional to the
pressure that is applied to the diaphragm.
FIXED RESISTOR
INPUT (+)
-m
INPUT ( —)
STRAIN GAUGE
FIXED RESISTOR
INSULATOR
DIAPHRAGM
BODY
PRESSURIZED FLUID
FLUID
16
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operate at temperatures of up to 450°F, although effective
operations of most are limited to 250°F. Rated pressures can
3De as high as 25,000 psi. Typical errors are around 0.5 per-
cent.
DOWNHOLE PRESSURE RECORDING DEVICES
Downhole pressure instruments are most commonly used
during formation testing. A downhole pressure gauge is com-
monly referred to as a "bomb." The bomb components are
either a Bourdon tube pressure gauge or a coil-spring assem-
bly, plus a strip chart recorder (see Figure 7). The chart
can be set to record over a certain time period, and then the
whole instrument is lowered — usually by wire-line down the
casing or borehole. After the designated time has elapsed,
the bomb must be raised to obtain the data.
Figure 7 shows a cross section of the two areas of an
Amerada bomb. The top part (recording section) contains
the clock, chart, and stylus; while the bottom unit (pressure
element) holds a helically-wound Bourdon tube, bellows, and a
maximum registering thermometer. The bellows is needed to
isolate the Bourdon tube from contaminating well fluids. The
bellows should be cleaned after each run, since it is often
exposed to corrosive environments. It should also be rou-
tinely checked to determine whether it is operating properly.
A common test to ascertain if the bellows has failed is
to push on it with a metal tube. A "spongy" feel to the bel-
lows, as opposed to a solid feel, indicates a leak in the
system (again, a maximum registering thermometer should be
17
-------
OUTER
HOUSING
CLOCK
CLOCK
CLUTCH
LEAD
SCREW-
CHART
HOLDER
LIFT
CHART
HOLDER
FOR FLAT
OR
FLANGED CHART
STYLUS
STEEL SAPPHIRE
OR DIAMOND
STYLUS
ASSEMBLY
B - III
OR
B - 229 ON
RPG -3 ONLY
CARRYING
PLUG
STYLUS
SHAFT
GUARD
STYLUS
SHAFT
ELEMENT
HOUSING
Figure 7,
BOURDON
JL ' TUBE
SUPPORT
ROD
The Amerada
RPB-4 Gauge.
Pressured
fluid enters
the bellows
and the
bourdon tube
which acti-
vates the
stylus
(Geophysical
Research
Corp.).
ELEMENT
. BASE
BELLOWS
«•( OPTIONAL)
UNBELLOWS
OR FILTER
OIL
TRAP
THERMOMETER
WELL
MAXIMUM
REGISTERING
THERMOMETER
( OPTIONAL)
RECORDING
SECTION (GAUGE)
PRESSURE
ELEMENT
18
-------
provided and used since the maximum testing temperatures
should be known and because the instrument calibration will
vary with temperatures). The recording section of the bomb
is used to generate a record of pressures encountered.
Coil-spring recorders use a piston, that moves due to
external pressure, to push a calibrated spring. A stylus is
provided to record pressures on the chart, and the stylus can
be driven by either a piston spring or a Bourdon tube; more-
over, it may have a steel, sapphire, or diamond point. The
chart is generally brass and it is coated on one side with
gray paint so that the pressure curve can be seen as a con-
trast between the colors, which are usually brass and gray.
The upper pressure limit of these instruments can be as
high as 20,000 psi with errors of 0.2 percent of full scale.
Special high temperature gauges can withstand temperatures up
to 500°F. Clocktimes range from 3 to 360 hours. Coil-spring
bombs may have errors of 5-10 percent of full scale.
Several types of downhole gauges may be permanently in-
stalled. One, made by Ball Brothers Research Corporation of
Boulder, Colorado, uses a Bourdon tube that telemeters data
to a chart/recorder at the surface; and, it uses a single
conductor cable. Recorded pressure curves often have a
"stair-step" appearance because the information transfer be-
tween the surface and downhole is not continuous. The gauge
is accurate to about 0.2 percent of full scale (Matthews and
Russell, 1967). Another gauge has a downhole transmitter
that consists of a steel cylinder with a diaphragm on one
19
-------
end and a taut wire that stretches from the diaphragm to the
cylinder body. A coil and magnet surround the wire and cause
it to vibrate. Changing pressures cause the diaphragm to de-
form; this in turn proportionally changes the frequency of
the wire vibrations, which allows the current change in the
coil to be transmitted to a receiver on the surface. Total
error can be as low as 0.25 percent with a recording range of
1,100 to 5,900 psi (Matthews and Russell, 1967)."
PRESSURE RECORDING DEVICES
Many instruments that measure pressure, flow, and tem-
perature (e.g., pressure transducers), can transmit electri-
cal signals to a receiver-recorder (see Figure 8). Electro-
nic recorders write on either circular or strip charts, • and
such recorders are discussed later in this report.
Most pressure gauges are self-contained units that me-
chanically display data with pointers. Connecting a recorder
directly to these gauges is impossible. Several manu-
facturers solve this problem by creating a recorder that
directly measures the deflection of a Bourdon tube that is
contained insides a recorder case (see Figure 9). The re-
corder resembles a 360-degree chart recorder' except that the
pen arm is driven mechanically by a Bourdon tube, instead of
electrical signals. The tube is directly connected to the
pressure source by a bendable hollow extension. A recorder
offered by C. E. Invalco can measure pressures of up to
10,000 psi with errors of only 1.0 percent of full scale.
20
-------
Figure 8. Electronic Receiver-Recorder (Omega, 1984)
21
-------
Figure 9 .
Mechanical Pressure Recorder. Typical recorder
made by Combustion Engineering, Inc. The
pressure line is to the right of the chart
drive. The line conducts process fluid pres-
sure to the bourdon tube (C), which in turn
guides the pen arm with a link (C. E. Invalco,
1984) .
J A D H L F B
A. PEN LIFTER
B. ADJUSTABLE STATIC
ELEMENT CONNECTION LINK.
C. STATIC. ELEMENT
MICRO - RANGE ADJUST
D. PEN ARM
.E. CHART DRIVE
F. PEN SHAFT ARM
S. STATIC ELEMENT
LINEARITY ADJUST
H. PEN ZERO ADJUST
I. AIRCRAFT HINGE
J. DOOR STOP
K. CLOSED CELL NEOPRENE
GASKET
L. PEN BRACKET (ONE PIECE)
M. ADJUSTABLE DOOR LATCH
-K
INTERIOR VIEW OF MODEL 212
22
-------
METHODS FOR TESTING PRESSURE INSTRUMENTS
Pressure instruments should be examined regularly, al-
though the frequency depends on the environment. Instruments
subject to high temperature and fluctuating pressures should
be checked for accuracy more than annually; and, devices
measuring pressure of highly corrosive fluids should be
checked more frequently for correctness.
Testing frequency will also depend on the type of in-
stallation; for example, a Bourdon tube or helical coil in
which a corrosive fluid is in direct contact with the gauge
should be checked for accuracy several times per year. If a
diaphragm separates the gauge from the corrosive substance,
less frequent testing may be required. Testing dates should
always be recorded on a chart, along with the amount of error
found on the gauge during the test. Corrective action, such
as recalibration, should also be included. A history of per-
formance of the pressure instrument will give the operator
or inspector an indication of how often the gauge is to be
tested or recalibrated.
Pressure instruments may be tested by the following
methods:
• use of a deadweight gauge tester
• use of one of many portable gauge testers that employ
a test gauge as a standard
Deadweight Tester
A deadweight tester uses primary weight measurements
that are based upon National Bureau of Standards' (NBS) data
for calibration to obtain about 99.9 percent accuracy over a
23
-------
pressure range of 15 to 10,000 psi. Each unit is ad-
justed for standard gravity conditions, thus local gravity
situations should be taken into account during testing
(Miller, 1983).
The apparatus consists of a hydraulic"pump that is-used
to. pressure a manifold; the manifold is connected to either a
precalibrated test gauge or a free floating piston which
holds calibrated weights and a tube which leads to the gauge
that is being tested (see Figure 10).
In use, the hydraulic pump exerts pressure against the
piston and the weights that ride on the piston. When the
piston and the weights spin freely, the pressure in the mani-
fold is equal to the total mass of'the piston and weights —
divided by the cross-sectional area of the piston. The gauge
or transducer being tested should read a value equal to this
calculated pressure throughout the scale (Dresser-Ashcroft
Form No. 250-1526-A). Tests also involve pumping the dead-
weight tester until the gauge shows its maximum reading.
Slowly releasing pressure after this test is an effective way
to scan for any sticking of the needle.
The deadweight tester is the ideal tool for testing in-
struments in the laboratory, due to its high degree of accu-
racy throughout the testing scale. However, the weights used
in testing should be periodically rechecked to provide assu-
rance that they conform to NBS standards.
Portable Gauge Testers
For field applications, where portability and ease of
24
-------
Figure 10.
Deadweight Tester and Portable Gauge Tester.
The same degree of pressure exits both open-
ings of the manifold. The pressure entering
the uncalibrated gauge can be compared with
weights (deadweight tester) or another gauge
(portable gauge tester).
UNCALIBRATED
GAUGE
TEST GAUGE
PLATE FOR WEIGHTS
PISTON
CYLINDER
DISC SEAT
PRESSURIZED MANIFOLD
PISTON
•HYDRAULIC FLUID RESEVOIR
25
-------
use are important, several manufacturers offer portable gauge
testers. These testers rely on less accurate means of mea-
suring pressure than the deadweights described above. For
example, Dresser-Ashcroft makes a portable test pump that is
interchangeable with its deadweight tester but uses a test
gauge instead of weights for calibration (see Figure 10; the
test range is from 15 to 10,000 psi with an error of 0.25
percent). Although accuracy is reduced, the whole assembly
is easier to carry into the field than a deadweight tester;
arid moreover, it does not have to be used on a level surface.
Dresser-Ashcroft also makes a portable gauge testing set that
weighs only about 12 pounds. Portability is gained in return
for a slightly higher error of within 0.5 percent and a lower
pressure range of 0-500 psi. These gauge testers consist of
a hydraulic test pump with two connections; one for a test
gauge and another for an uncalibrated gauge.
Yet another type of portable gauge tester is manufac-
tured by 3D Instruments (see Figure 11). The unit has a
cylindrical reservoir which connects to a manifold; two pump
handles are placed underneath the manifold and opposite to
each other. A transparent reservoir is filled with water 'and
a 1/4-inch hose 'is connected to the gauge to be tested. The
handles are pumped manually until the test gauge reads a de-
sired pressure; the vernier knob is then used to adjust the
pressure gauge to the proper value.
26
-------
Figure 11.
Portable Gauge Tester. Both a test gauge
.and an uncalibrated gauge can :be attached
to the tester at the same time (3D Instru-
ments, Inc. 1981).
PRESSURE GAUGE
(typical )
HOSE
VERNIER ADJUSTMENT
HYDRAULIC
PUMP
PNEUMATIC
PUMP
NEEDLE
VALVES
27
-------
CALIBRATING PRESSURE GAUGES
If any inaccuracies in a gauge have been found during
testing, it is important that the gauge be either cleaned or
recalibrated. Some calibration procedures can be performed
easily and quickly, while others require special tools,
*
knowledge and time.
In order to restore a gauge to efficiency, sometimes, a
complete replacement of the movement and linkage is needed.
Often, however, just cleaning the parts or calibrating the
gauge is all that is required; frequently, only a pointer ad-
justment is needed which is called "rezeroing" (Dresser-
Ashcroft Form No. 250-1526-A).
There are many ways to adjust pointers in gauges (some
gauges have adjustable gears or. friction bushings, while
others have a cam adjustment which rotates the entire move-
ment) . If the pointer is nonadjustable, it is necessary to
•loosen the-pointer and retighten it at another position. In
C-type (Bourdon) tubes (see Figure 12) hairsprings should be
tightened with a tweezer to maintain sufficient torque
throughout the gauge range.
Pressure gauge manufacturers have a variety of ways to
change the pivot radius and they should always be contacted
if such change is needed; the same is true when linearity
adjustments are necessary. When calibrating liquid-filled
gauges, the liquid must be initially drained (Dresser-
Ashcroft Form No. 250-1526-A).
28
-------
Figure 12
Bourdon Gauge Components (Dresser-Ashcroft,
250-1353-H).
POINTER
BUSHING
POINTER
SPRING
ROTARY MOVEMENT
SHOWN.
BOURDON TUBE
SEGMENT
BOURDON TUBE TIP
ANGLE OF PULL
CONN.;LINK
SLIDING PIVOT TYPE
SPAN ADJUSTMENT
SHOWN
SEGMENT PIVOT
RADIUS
29
-------
Pointer adjustments required under certain circum-
stances are summarized below:
Pointer Behavior . Corrective Action
1. Pointer behaves in uniform 1. Adjust span
manner except above or be-
low maximum scale at maximum
pressure. < .
2. Pointer travels too far 2. Increase pivot radius
3. Pointer does not travel far 3. Decrease pivot radius
enough
The above calibration procedures' do not apply to gauges
with helical, coils because the tube designs are relatively
simple; all that is generally necessary for recalibration is
either a pointer adjustment with'a screw or a replacement of
the coil.
While pressure transducers can be rezeroed at the re-
ceiver, linearity cannot be so adjusted. A loss of linearity
indicates that the transducer must be replaced.
Pressure "bombs can be calibrated with a deadweight tes-
ter; first, the recording element should be checked by in-
stalling a protractor on the element and a pointer on the
stylus shaft. If the movement is smooth and complete under
pressure, the test may begin. To calibrate — simply apply
five or ten known pressures, starting from the maximum and
going to the minimum; then spin the chart:holder to have it
read the corresponding pressures and then set. Again, if
nonlinearity results, the element should be replaced.
• Since most downhole pressure recorders are of unique de-
signs, the manufacturers should be consulted for calibration
30
-------
procedures.
"NEGATIVE" PRESSURE GAUGES -
In cases in which a well injects into an underpressur-
ized formation, pressure at the well-head could be lower than
the atmospheric pressure. In these cases, accurate injection
pressure readings can only be attained with a gauge that mea-
sures absolute pressure. The primary measuring elements in
these gauges would have to be isolated from the atmosphere
and the instrument would have to be more 'sophisticated than
regular pressure gauges. Pressure gauge systems that contain
one absolute and one "positive" gauge are commonly known as
compound gauges. Several manufacturers produce absolute and/
or compound gauges. A complete list was not available at the
printing of this document (see the list of Manufacturers of
standard pressure instrumentation at the end of the docu-
ment). Prices for these gauges and recording devices range
from around $15, to several thousand dollars for very accu-
rate gauges with recording devices.
"Negative" pressure gauges can have ah application in
measuring less than atmospheric conditions in injection
wells. These measurements can be used in determining pres-
sure vs. injection rate trends which can be analyzed to
determine the mechanical integrity of the tubular goods;
this is because any significant departure from the trend
can signal changes in the injection conditions. However,
if the well has an isolated annulus, a more sensitive mech-
anical integrity tracking system would consist of monitoring
31 :
-------
changes in the annulus pressure, especially if it is higher
than the infection pressure.
OPEN ANNULUS WELLS
Open annulus (also known as fluid seal) wells can be of
two designs, static and dynamic. Static systems are by far
the more common; it is for this reason, only static systems
will be discussed here. The difference in the two is whether
the liquid in the annulus is contained there or comingled
with the injection fluid at the bottom of the well. A static
open annulus well uses .two "immiscible" fluids that interface
in the bottom of the annulus and isolate it from the
injection fluid.
• The annulus fluid level is' monitored to estimate the lo-
cation of its interface with the injection fluid. This esti-
mate allows the operator to infer the mechanical integrity of
the casing and tubing. One such monitoring assembly consists
of a graduated holding tank that is connected to the annulus;
the tank is used to keep a positive pressure on the annulus.
The annulus is filled usually with a noncorrosive fluid to a
reference level on the holding tank. A significant casing
leak is generally indicated by a drop in fluid level as it
drains into the formation adjacent to the point of leakage.
If tubing pressure exceeds annulus pressure, a leak in the
tubing can result in a rise in the fluid level.
A way to continuously record the annulus fluid level is
to use one of two models of Stevens recorders (types A or F).
Each of these recorders uses a float, which rises and falls
32
-------
with the fluid level. The float is connected to a pulley by
a cable. On the Type F recorder, the pulley rotates a drum
that is marked with a steady moving pen. On a Type A record-
er, the pulley moves the pen as the water level changes.
Both record fluid levels versus time on the charts.
FLOWMETERS
TYPES OF FLOWMETERS
Flowmeters can be classified into distinct groups; that
is, positive displacement meters and inference type meters.
Positive displacement meters measure flow directly by sepa-
rating the flow stream into segments of known volumes and
counting them (Reason, 1983), while inference meters infer a
flow rate by measuring a certain dynamic property of the flow
stream that is proportional to the flow rate. Below is a
listing of seven of the most used inference flowmeters:
• Turbine
• Differential Pressure Producing
• Sonic
• Doppler
• Float Type
• Electromagnetic
• Vortex Shedder- Meters
Table 2 lists the most common types of flowmeters along
with their approximate accuracies, pressure limits, and other
important parameters. All of these values are general and
may vary among manufacturers and between the separate models
offered by a single manufacturer. Table 3 lists construction
materials which should be used in flowmeters for various
chemical exposures.
The following section contains some basic calibration
33
-------
TABLE 2
DIFFERENT FIOWMETHR SPECIFICATIONS
FUmmeter
Oscillating
Piston
Hut ut Ing
Paddle
Oval Gear
Rotating
Vane
Pi at on
Bearing-
less
TUrbine
Single
Inpeller
TUrbine
Orifice
Typical
Application
Slurries,
acids
solutions
Wide variety
of liquids
Wide variety
of substances
Wide variety
of ] 1 quids
Non corrosive
Highly corro-
sive
Clean fluids
Water
Clean fluids
Maximum
Pressure
150
1,440
275
1.440
275
300
500
150
600
Maximum
Tenperatura*
300°F
450°F
200°F
200°F
.180°F
266°F
850°F
150°F
700°F
Maxinun
Flow rate/
Velocity**
35 gpm
. 1,250 gpm
150 gpm
8,750 gpm
20 gpm
320 gpm
50,000 gpm
2,250 gpm
25,000 gpm
Advantage
Magnetic pickoff,
no contact with
gears
low pressure loss,
wide range of vis-
cosities
Wide application,
viscous liquids
Low pressure
drop, wide range
of viscosities
Low flow, counter
Handles corro-
sives
Out be more accu-
rate than rating,
precise
Inexpensive, high
flow
Inexpensive, high
flow
Drawback
Vulnerable to
extremes
Fluids with
solids
Fluids with
solids
Liquids with
solids
Liquids with
solids
Liquids with
solids
Liquids with
solids
Narrow appli-
cation
High head
loss, inac-
curate during
low flow
Error
0.5%
0.2%
0.5%
0.5%
0.5%
2.0%
0.5%
2.0%
1.0 -
3.0%
Manu-
facturers
Badger
Uquid
Controls
Smith
Snlth
Tbkhelm
C.E. Invalco
C,E. Invalco
Snlth, Flow
Technology
Badger
Badger,
Anetek,
Daniels
General Price***
f 2.000 for 2-inch
$ 2,000 for 2-inch
$ 4,130 for 2-inch
$20,000; $3,600
for 2-lnch with
counter
f 830 for 1-inch
with counter
$ 1,240 for 2-inch
$ 6.500
? 1,100
$ 150+ with flange
$530
-------
cn
TABLE 2
(continued)
Flowneter
Nozzle
Flow Tube
Venturi
Tube
Sonic
Doppler
Float
Electro-
magnetic
Strain
Gage
Nutating
Disc
Vortex
~ Shedding
Typical
Application
Clean fluids
Sludge, oils
acids, water
Sludge, oils
acids, water
Clean liquids,
any type
Suspended
solids
Clean liquids
Sewage, other
conductive
liquids
Liquids, dirty
corrosives
Clean corro-
sives solvents
Wide variety
of liquids
Maximum
Pressure
4,000
500
4,000
3,000
Exterior
8,960
300
5,000
150
1,500
Maximum
Temperature*
800°F
800°F
800°F
300°F
140°F
752°F
356°F
700°F
250°F
580°F
Maximum
Flow rate/
Velocity**
25,000 gpm
25,000 gpm
25,000 gpm
lOft/sec
48-inch
pipe
35ft/sec
660 gpn
30ft/sec
40ft/sec
20 gprn
2,850 gpm
Advantage
High flow, high
pressure
low head loss,
high flow
Low head loss,
high flow
Piggable, large
diameter pipe
Piggable, good
for dirty fluids
Simple, inexpen-
sive
Piggable, only
3-5 diameter pipe
lead needed
. Simple, with-
stands extremes
lew flow, counter
Simple, durable
Drawback
High head
loss, inac-
curate during
low flow
Inaccurate
during low
flow
Inaccurate
during low
flow
Liquids with
solids
Clean liquids
Liquids with
solids
Noneonduct ive
liquids
High head loss
for anall pipes
Vulnerable to
extremes
Not piggable,
affected on
overrange
Error
1.0 -
3.0%
1.0%
0.8%'
2.0%
2.0%
1.0%
1.0%
0.5%
2.0%
1.25%
Manu-
facturers
Badger
BIF, Badger
BIF, Badger
Mapco
Mapco
Krone,
Ametek
Krone
Ramapo
Tokheim
Fischer &
Porter
Yokogowa
Ibxboro
General Price***
$ 2,000+
$ 3,000
$ 3,300
$ 2,500
$ 1,400
$ 400 for
$ 3,500
$ 2,500
$ 656 for
2- inch
1-inch
$ 1,250 for 2-inch
installed cost
competitive with
orifice plate
meters
* Depending upon materials and size.
** Percent of flow rate. The accuracy is stated by the manufacturer and is not specific to any viscosity or temperature.
*** 8-inch pipe except when otherwise stated. 1985 prices (•*• Plus $1,000 for transmitters)
-------
TABLE 3
FLOWMETER MATERIAL .RESISTANCE .
(Smith Meters, 1980)
Material Used
for Flowneter
Aluminum
Bronze
Cast Iron
Tungsten Carbide
Carbon Steel
Austenitic Stainless
Steels
Buna-N
Viton A
Ethylenes, Propylenes
Teflon* '
Resistant To
Organic acids, amines, sol-
vents, alcohols, ketones
Solvents, acetates, esters,
alcohols, ketones, petro-
leum solvents, glycols,
aromatic hydrocarbons,
water
93-95% sulfuric acids, alka-
lis, hydroxides, ammonia,
amines, solvents, alcohols,
ethers, ketones, petroleum
solvents
Dilute and concentrated
sulfuric and hydrochloric
acids, brine
High resistance to petroleum
products
Organic acids, amines, hy-
droxides, food products,
fatty acids, anilines, sol-
vents, alcohols, ethers,
ketones
Petroleum products, water,
ethylene glycol fluids
Aromatic hydrocarbons, acids,
halogenated hydrocarbons
Ketones, alcohols, •water,
steam
Most chemicals
Not Resistant To '
Hydroxides, acids,
acid salts, alka-
lis
Mineral acids,
amines, alkalis,
hydroxides
Organic acids,
dilute acids
Oxidizing acids
(nitric), organic
acids (lactic and
citric)
Acids, water
Mineral acids,
concentrated acid
salts
Ketones, acids,
halogenated hydro-
carbons
Ketones, amines
Petroleum products
Hydrofluoric acid
36
-------
TABLE 3
(continued)
Material Used
for ELowneter .• Resistant To Not Resistant To
Ryton** ' Most chemicals Most oxidizing
acids
Carbon Pure-Bon*** Ifost chemicals Strong oxidizing
acids
* Trademark E. I. DuPont
*-* Trademark Phillips Petroleum Company
*** Trademark Pure Carbon Company
37
-------
adjustment information for most flowraeters; however, specific
procedures vary for each type and make of meter. The manu-
facturers should therefore be consulted if detailed calibra-
tion procedures are needed (see Appendix A).
OPERATIONAL PRINCIPLES
Positive-Displacement Flowmeters
Positive-displacement meters measure volumetric flow di-
rectly by continuously separating a flow stream into discrete
volumetric segments and then counting them. Several types of
positive-displacement meters are illustrated in Figures 13
through 16. Although the specific method of flow segregation
varies, common characteristics of all positive-displacement
meters include:
• Can be used on lines ranging from 1/4-inch to 16
inches '
• Can handle pressures up to 1,440 psi although most
are made to withstand much lower pressures
Can be designed to measure almost any flow rate
Can be accurate to within 0.2 percent of full scale
Can operate better at lower pressure
Can not be cleaned through the use of a "pig"
Can use the energy of flow to drive the counter
through a gear train .
Can not be used with fluids that contain solids or
grains.
In the Bi-Rotor oval gear meter (see Figure 13) two rotors
are geared together and each revolves about a shaft. Water
entering the meter causes the rotors to revolve, but only the
water trapped in the measuring chamber (hatched section)
passes through the meter. Two volumes of measured water pass
for each single rotation of a rotor. The rotor revolves
freely around a non-rotating shaft which is hollow and houses
a second rotation shaft in its center. The rotation of the
38
-------
Figure 13 .
Bi-Rotor Oval Gear Meter. The two rotors
(bottom) move with the flow (Smith Meters,
1977}. . '
DRIVING MAGNET
( Kynar Coated )
BEARING
NON ROTATING
SHAFT
BEARING
DRIVEN
MAGNET
ROTOR
39
-------
Figure 14. Ro-tating-Paddle Meter. Exterior gears on
each paddle move the upper main paddle,
which records data.
CROSS SECTION
ROTATING PADDLES
40
-------
Figure 15.
Oscillating Piston Meter. Fluid enters the
intake/ bounces off the barrier, and al-
ternatively pushes (solid) and pulls (dotted)
the piston vertically.
PISTON
AXLE
PISTON
FLOW
OUTLET-
'-FLUID INTAKE
L—BARRIER
41
-------
Figure 16.
Rotating Vane Meter. The cam forces the
blades to extend and then contain a dis-
crete volume of fluid (Smith Meters,
1977) .
CAM
MEASURING
CHAMBER
3 LAOS
PATH OF
BLADES
FLOWING
LIQUID
METER
HOUSING
BLADE'
SEARING
ROTOR
42
-------
rotors is magnetically coupled to the second shaft forcing it
to rotate in proportion to the amount of liquid passing
through the meter; this rotation is then metered.
The other rotating meters (see Figures 14-16) operate on
similar principles. A complete discussion;of positive-dis-
placement meters may be found in the Handbook on Process
Instruments by Douglas Considine.
Positive-displacement meters generally have a calibra-
tor that fine tunes the output of the counter in 0.05 per-
cent increments, usually over a 5.0 percent total adjustment
range. Because 'differing viscosities alter calibration, a
positive-displacement meter should be calibrated after its
installation. Positive-displacement meters are considered to
be the best flowmeters for higher viscosity fluids (fuel or
crude oil), which tend to cause inaccuracies with other types
of meters (Reason, 1983). Positive-displacement meters sel-
dom have tp be recalibrated when used with low--viscosity,
clean liquids, such as water (Ginesi, Greby, 1985). On the
other hand, frequent recalibration may be necessary if the
meter is used to measure volumes of heavy .oils or fluids
that contain solids. Fluids that contain solids cause ex-
cessive wear of parts through mechanical friction which can
degrade.the accuracy of the meter. Meters that are used with
liquids such as heavy oils should be recalibrated at least
once a year; however, past meter performances will dictate
better the frequency of recalibrations needed.
43
-------
Turbine Flowmeters
Turbine meters infer flow rate by measuring the rate of
the revolutions of a bladed rotor. To obtain a volumetric
flow rate it.is necessary to assume that the flow rate is
proportional to the stream velocity, and that the stream
velocity is proportional to the rotor angular velocity. A
turbine meter usually has three basic sub-assemblies (see
Figure 17) which.are the body, the rotors ^(turbines), and the
pickup (Miller, 1983). The turbine meters that contain the
sub-assemblies, can come in almost any size, flow, and pres-
sure rating. A wide variety of materials are available (see
Table 3). The most important part of the meter is
the bladed rotor which is suspended in the flowing stream on
the platform bearing and rotor shaft. The rotor should have
regularly spaced paramagnetic material to allow for the de-
tector 's pickup coil to monitor revolutions of the rotor.
Turbine meters, which can be accurate to within 0.5 percent
of flow rate or better, have been constructed to withstand
flow rates to 50,000 gpm and pressures to 500 psi.
Of interest is the fact that one form of turbines uses
only a single impeller. It is frequently classified-as a
"water meter" because it is often used on water mains. The
meter contains a single, long impeller (instead of a rotor
assembly) which is connected, by way of bearings, to either a
geared shaft or a cable. This assembly leads to a magnetic
pickup housing (Badger Meter, DMR-110). Impeller meters are
less accurate, about 2 percent error full range, than stan-
44
-------
Figure 17. Major Components of a Turbine Meter (C. E
Invalco, 1984). .
BODY
MAGNETIC
PICKUP
FLOW
DIRECTION
ROTOR
SUPPORT
45
-------
dard turbine meters because of the impeller design.
Another turbine meter incorporates two rotors which are
connected by a vertical shaft (see Figure 18). When fluid-
flow begins, the rotors are floated above their seat as the
stream flows between them. The rotors spin without the need
for shafts or bearings; bearing wear and friction are there-
fore eliminated. These bearingless flowmeters are especially
useful for highly corrosive liquids; but, they are only ac-
curate to within 2.0 percent of the flow rate.
The best method for judging the performance of a turbine
meter is by the repeatability of its K-factor (pulses per
gallon) under identical conditions and by its accuracy
throughout a flow range. Figure 19, shows a sample chart
which lists the K-factor for certain size meters. The small-
er the meter, the higher the K-factor. Figure 20, is a typi-
cal turbine flowmeter performance curve which depicts the
K-factor variation which must be considered when extreme
accuracy is desired.
A common method to measure meter accuracy is to run two
meters in series and compare their readings (Smith Meters,
1977). A highly accurate, portable turbine meter kit is
available to test and calibrate turbine meters on-site. The
kit contains several flowmeters, each made for a certain vis-
cosity range, with accuracy ranges to within 0.25 percent and
a precision rating to within 0.05 percent.
•Turbine meters are made for fluids without particles.
Obstructions and solids can seriously affect the accuracy of
46
-------
the meter; thus, a removable mesh strainer should be install-
ed ahead of the flowmeter for protection. As a rule-of-
thumb, a meter should have 10 diameters length of
straight pipe upstream and downstream and the mesh strainer
should also be installed at this distance from the meter.
Turbine flowmeters should not be located near electric- mo-
tors, transformers, sparking devices, or high-voltage lines.
Figure 18. Bearingless Flow Meter. The shaft and rotors
• . float during flow.• A magnetic pickup records
their spin (C. E. Invalco, 1984).
SHAFT AND
UPPER ROTOR
ASSEMBLY
-Ot
LOWER ROTOR
LOWER HOVER DISC
MAGNETIC PICKUP
XP ADAPTER
UPPER COVER
- BODY
LOWER COVER
LOWER
RETAINING PLATE
47
-------
Figure 19
Flow Ranges and
1984).
'K" Factors (C. E. Invalcof
Bodv
Si/.e
V*~
1"
\<2"
Rep«alable
Flow Ranee
Min.
.8
4.7
13
25
45
Max.
16
77
209
400
700
Linear
Flow Range
Si in.
1.4
6.6
17.6
33.7
60.0
Max.
14
66
176
.137
600
*Pulses Per
Gallon
K-Factor
4330
910
340
178
51
'Data based on water calibration ai 20° C.
Figure 20.
Typical Turbine performance Curve.
Factor versus flow rate percentage
(Smith Meters, 1977).
IO-
METER
"K"FACTOR
PULSES/BBL
LINEARITY
REPEATABILITY
ZS'i 50% •n=-a
METER FLOW RATE - % MAXIMUM
48
-------
Differential Pressure-Producing Flowmeters
Differential pressure-producing flowmeters use a flow
restrictor, usually called a primary element, to decrease
the cross sectional area of a pipe. As a .fluid passes
through the restricted area, its velocity increases. A re-
sulting drop in pressure occurs due to the conservation of
• energy as described by the Bernoulli equation. Pressure
sensors are located at either side of the restricted area to
measure the pressure differential that is the result of flow.
The differential pressure is proportional to the square of
the flow rate, so the square root of the differential pres-
sure is used to determine flow volumes.
A variety of'primary elements exist on the market. They
either fit inside a section of pipe, or are placed between
two sections. In order for the element to' work correctly, up
to 30 diameters of.straight pipe must be run before, and 15
diameters after, the element. Some of the more common types
of primary elements are orifice plates .(see Figure 21), flow
nozzles (see Figure 22), flow tubes (see Figure 23), and ven-
turi tubes (see Figure 24); the latter two are useful for
fluids that contain solids, such as sewage, and high flows of
up to 25,000 gpm because of their relatively low pressure
losses. Flow nozzles and orifice plates should not be used
for fluids containing solids because deposits tend to accumu-
late, and their accuracy is affected. Flow nozzles work well
with high pressure steam and fluids under pressures up to
4,000 psi. Primary elements, especially orifice plates,
49
-------
Figure 21.
Schematic Diagram of a Working Orifice Plate.
Pressure decreases as the fluid velocity
increases through the plate.
HIGH PRESSURE
TAP
LOW PRESSURE
TAP
ORIFACE PLATE
50
-------
Figure 22. Schematic Diagram of a Working Flow Nozzle.
HIGH PRESSURE
TAP
LOW PRESSURE
TAP
FLOW NOZZLE
51
-------
Figure 23. plan View of a Flow Tube (Badger Meter, Inc.,
1981).
TYPICAL
HIGH PRESSURE
CONNECTION
TYPICAL
LOW PRESSURE
CONNECTION
ANNULAR CHAMBER
52
-------
Figure 24. plan View of a Venturi Tube (Badger Meter,
Inc., 1962).
LINE SIZE
REMOVABLE COVER FOR
CLEANING 8 INSPECTION
- LOW PRESSURE CONNECTION;:
3/4"NPT
HIGH PRESSURE;CONNECTION
3 /4" NPT
53
-------
cause pressure losses and are not piggable.
The accuracy of a primary element can be checked by
placing a manometer in the pressure sensor opening without
having to shut down the flow (Halmi, 1976). To maintain the
calibration when using fluids that contain solids, the inte-
rior surfaces should be finished with a deposit-resistant
material;' a primary element also should be easily accessible
through a large opening to facilitate checking and cleaning
of any deposits. Some factors that determine the adequacy of
instruments using orifices as the primary measuring devices
are:
Tolerance of meter tube bore
Uniformity of flow profile •
Fabrication of the orifice plate
Installation of the orifice plate
Wear of the orifice plate and metering tube
An important aspect of differential pressure flowmeters
is the manner in which the differential'pressure, and there-
fore flow rate, is determined. These systems, when first de-
veloped, used two piezometer standpipes. Tubes ran from the
pressure sensor holes to two standpipes that were filled with
the pipe fluid. The fluid levels in the standpipes changed
with the flow velocity. A more common measuring technique
is to use a bellows transmitter (differential pressure
transmitter) with both tubes running from the meter to each
side of a bellows.
The position of the bellows varies with differential
pressure which changes the signal that is emitted from the
transmitter. Other transmitters use the pressure from the
54
-------
tubes to push mercury within a manometer to move a core
within an induction coil to produce a voltage which
can be recorded electronically. Due to the toxic charac-
teristics of mercury, other liquids are now used.
With some brines or other particle-laden fluids, pres-
sure lines can clog even when equipped with elaborate flush-
ing systems. To solve this problem, some current differen-
tial pressure flowmeters use a liquid-filled probe with a
diaphragm set flush to the inside of the primary element. A
small motor inside the probe applies an equalizing pressure
to the dry side of the diaphragm. The differential pressure
is recorded by a transmitter.
Electronic transducers are more susceptible to fouling
than differential pressure transmitter systems; therefore,
most operators use the simple pressure transducer, especial-,
ly for fluids that do not precipitate. The accuracy of all
probes can be checked with a manometer without shutting down
the system,
Sonic Flowmeters , .
Sonic flowmeters use the speed of sound to estimate the
speed of fluids in a pipe to extrapolate their flow rate.
Most types use two transducers pointed at each other and set
at a 45 degree angle to, or inside the pipe (see Figure 25).
One transducer emits ultrasonic waves while the other re-
ceives them. The moving fluid affects the speed of the
ultrasonic waves in proportion to the flow rate. Sonic
flowmeters can measure any moving liquid; however, the
55
-------
Figure 25.
Sonic Flowmeter. The speed of sound from
Transducer A to B is substracted by the
speed from B to A. The difference in the
speed of sound measured from A , to B and
transducers B to A is proportional to the
flow rate (Mapco, 1984).
B
FLOW
III
DIRECTION
56
-------
performance of meters that are clamped to the exterior of the
pipe can be greatly affected by the pipe material, especially
with fiberglass and cast iron pipes. Sonic flowmeters should
not be used for metering liquids with large amounts of solid
particles; even a few gas bubbles can cause problems. Sonic
•
flowmeters can handle flows up to 10 ft/sec in pipes as large
as 48-inch and pressures as high as 3,000 psi.
Zeroing sonic flowmeters can be accomplished in the
field, while rescaling requires special instructions or a re-
turn to the dealer/manufacturer. A sonic flowmeter has the
advantages'of being piggable, and able to deal with large
volumes, high pressures, and to handle corrosive fluids.
Doppler Flowmeters
Doppler ultrasonic flowmeters utilize the Doppler Effect
to estimate the speed of a liquid traveling through a pipe.
The fluid must contain either solids or bubbles for the meter
to work correctly. A transducer transmits a sonic wave which
reflects off particles in the -fluid onto a receiving
transducer (see Figure 26). The difference in frequencies of
these two sonic waves serves to calculate the fluid velocity.
The accuracy of the flow rate measured by a Doppler flowmeter
is affected by the accuracy of the measured internal diameter,
since this measurement is used to calculate the volume of the
fluid in the pipe. Concrete, certain heterogeneous media, or
pipes less than one inch in diameter cannot be monitored by
Doppler meters. However, the big advantages of Doppler flow-
meters are that they are portable, do not interfere with
57
-------
Figure 26. Doppler Flowmeter. The pitch of the sound
from a passing car changes and 'is explained
by the Doppler effect. It also affects the
reflection of. sound from particles inside
the pipe. The particles accelerate the
sound waves that emanate from a transmitting
element (Mapco, 1981) .
TRANSMITTING RECEIVING
ELEMENT ELEMENT
TRANSDUCER
ADHESIVE
DIRECTION OF FLOW
58
-------
flow, and because they are mounted on the pipe's exterior can
handle any pressures.
Like other sonic type flowmeters, zeroing Doppler flow-
meters is simple but rescaling is usually difficult. Opera-
tors often must consult the manufacturer for help.
Float-Type Flowmeters
Float-type flowmeters (sometimes called rotameters, or
variable area meters) operate on the float principle and have
an upright conical metering tube made of glass, metal, or
plastic. Inside the tube is a float (see Figure 27) which
moves up as the" fluid enters through the bottom of the meter.
The float rises proportionally to the flow rate. Transparent
flowmeters have a scale set on the meter which shows the flow
rate per height of the float, Flowmeters with a plastic or
metal metering cone magnetically transmit 'the value of the
flow rate. While most see-through, glass-float meters cannot
withstand.high pressures, Krohne makes a metal-float meter
that can withstand pressures of almost 9,000 psi. Fischer
and Porter also make a heavy-duty model that withstands 3,000
psi. Flow rates are generally limited to. less than 700 gpm
with this type of meter.
While float-style flowmeters can be used for fluids of
different viscosities, they should not be used with fluids
that contain solids. Deposits could change the weight and
flow properties of the float which would severely retard its
accuracy. Float-type flowmeters should never have to be re-
calibrated if kept clean.
59
-------
Figure 2,7.
Typical Transparent Float Flowmeter. The
incoming fluid lifts the float to -a height
that is proportional to the rate (Ramapo
Instrument Co.).
INLET
ROTAMETER
TUBE
60
-------
Electromagnetic Flowmeters
Electromagnetic flowmeters, sometimes called magnetic
induction flowmeters, create a magnetic field which sur-
rounds the fluid passing through the pipe. The field coils
of the meters are energized by a pulsed B.C. current or by
line alternating current. When the fluid flows through the
magnetic field, a voltage proportional to flow velocity is
induced. The current produced is monitored after passing
through the electrodes which are at right angles to the
field coils (see Figure 28). Fluid electrical conductivity
level should be at least 0.05 us/cm (Microsiemens/centi-
meter) to 20 ]is/cm for these meters to operate. The conduc-
tivity of drinking water is generally 500 jis/cm; therefore,
magnetic flowmeters have many applications for metering con-
ductive fluids such as water and sewage.
Advantages of the electromagnetic flowmeter are:
• No pressure loss occurs and the system is pig-
gable if the proper size meter is used
• The pipe liner and possibly the electrodes are
in contact with the fluid
• Measurements are independent of the flow profile
and other properties of the fluid
• They measure flows up to 15,000 gpm with accuracies
that range from within 98 to 99.5 percent
However, the pressure limits are rarely more than 600
psi. Direct-current meters have the advantages of continual
and automatic zero-point correction that occurs between each
pulse, and reliable suppression of interference voltages.
Alternating-current meters can be rezeroed by the operator,
61
-------
Figure 28. Principles of Magnetic Flowmeters. The medium
flows at a certain velocity (V) inside a pipe
of a certain diameter (D) and passes through
the magnetic field (B) and the electrodes pick
up the induced voltage (U) (Krohne, Product
Guide 3).
62
-------
but special equipment is often required.
Vortex-Shedding Flowmeters
The principle of operation of a vortex-shedding flow-
meter is to generate turbulence which is then used to monitor
flow. A narrow vertical bar, called'a vortex shedder (see
i
Figure 29), produces eddies that pulse from alternating sides
of the bar during flow. A torque tube twists with these
pulsing vortices, whose frequencies are proportional to the
flow rate. Strain gauges sense the tube movement and trans-
late that movement into a flow rate. ;
The advantages of vortex-shedding flowmeters are their
accuracy, linearity over a wide range, physical strength, and
the fact 'that deposits normally do not form on them. Since
the sensor rests outside the meter, the pulses from the
strain gauge can be related to a full scale flow value and
therefore can be "calibrated" without having to shut off
flow. Vortex-shedding flowmeters, however, are not piggable.
The vortex-shedding flowmeters are available in dia-
meters up to 8 inches and can handle flow rates up to 3,000
gpm. They are accurate to within 0.5 percent of the flow
rate, although their full scale rating is usually over 1.0
percent.
Other Flowmeter Designs
Flow can be measured by a variety of means, especially
when the rate is inferred. One design uses an object of
known area which is placed inside a flow stream and connected
to a strain gauge. The stress on the object is proportional
63
-------
Figure 29.
Cut-away View of a Vortex-shedding Flowmeter.
The fluid strikes the shedder bar and vortices
alternately push the two sides of the sensing
vane (Fischer and Porter, 1983).
METER BODY
SENSOR
LINK
TORQUE TUBE
( CUTAWAY)
SENSING
VANE
VORTEX
SHEODER BAR
64
-------
to the flow velocity. Calibration can be performed by ap-
plying a known force to the object. Strain-gauge flowmeters
are accurate to within 0.5 to 2.0 percent of full range and
can withstand pressures as high as 5,000 psi. Another design
has a vertical axle that supports a flat-lying disc; when the
plane of the disc is tilted at a low angle, the disc nutates
about the axle as fluid is passing, which gives the meter the
names, "wobble meter" or "nutating-disc meter." With a 2-3
percent error, the wobble meter is not as accurate as posi-
tive-displacement or turbine meters, but it is less expen-
sive.
A variety of other flowmeter variations exist on the
market. However, they are not nearly as common as the seven
major forms of inference meters discussed above.
TESTING AND CALIBRATING FLOWMETERS
While all flowmeters are calibrated in the factory, re-
calibration may be necessary upon emplacement. This is done
because viscosities, pressures, and temperatures can vary
from the laboratory conditions where the meter was originally
tested (Halmi, 1976). Flowmeters eventually wear, corrode,
or accumulate deposits, and they require recalibrations.
Operators should follow the manufacturer's recommendations on
procedures and frequencies of calibration.
Venturi tubes and other differential-pressure devices
can be checked by placing manometers on the pressure open-
ings. Most powered meters can have their frequency or vol-
tage output checked by an electronic test indicator. Some
65.
-------
meters such as D.C. pulse or ultrasonic may require elec-
tronic calibration. These procedures would not be accurate
if either deposition or corrosion changed the internal areas
of the meters. Test results may also vary depending upon
line pressures, viscosities-and temperatures. The most as-
sured way of checking flowmeter accuracy and calibration is
to perform direct volumetric tests with a prover.
Provers may be used for any type of f lowmeter,, but they
are limited by pressure, temperature and type of fluid being
measured. The most common and inexpensive prover is the vol-
umetric prover tank. It is a tank, ranging from a five-
gallon portable to a 1,000 gallon laboratory model, that is
marked off with precise fractions of gallons (the tank should
adhere to determinations by the National Bureau of Stan-
dards). The liquid from the flowmeter should be timed as it
is allowed to flow into the tank.
Piston or ball-type provers are more convenient than
tanks (see Figure 30). They use a piston or ball which is
pushed along within a smooth bore tube by pressurized gas.
The piston or ball in turn displaces a known volume of fluid.
Electrodes on the displacer (piston or ball) generate pulses
as it passes two fixed points that define a specific volume
in the tube. The electrical pulses are counted and timed.
Some provers generate a continuous train of electrical pulses
for more precise measurement (Cook and Strongman, 1984). The
prover may be sensitive to solids, dirt, etc., which inter-
fere with mechanical actions. However, the prover is
66
-------
Figure 30.
Schematic Diagram of a Piston Prover. The
piston travels to the other sensor (dashed
position) while pushing a standardized
volume of fluid out of the prover. The
valves reverse to return the piston.
PISTON
OISPLACER
CONTROL VALVE (S)
.STANDARDIZED
VOLUME
67
-------
unaffected by the fluid viscosity and density in determining
the volumetric flow that goes through a flowmeter.
Differential pressure flowmeters are not volume measur-
ing devices. They should be calibrated for each fluid which
is metered depending on its viscosity and specific gravity.
FLOW RECORDING DEVICES
Many flowmeters require transmitters or signal conver-
ters to send the signals (mV, V, or mA) that a recorder can
accept. Others such as magnetic or turbine meters do not re-
quire transmitters or signal converters since the signal can
be accepted directly by the recorders.
Others, like positive-displacement meters, use geared
counters to measure flow and need a pulse transmitter. Pulse
transmitters attach themselves to the exterior of counters,
and then they convert the geared movements into signals.
An electronic recorder can be one of two standard de-
signs; the circular chart recorder and the strip-chart
recorder. The circular recorder (see Figure 8) rotates a
chart on an axle. A pen is provided to record pressure
or flow rate on the chart. The pressure or flow rate scale
lies along the chart radius and the time axis is the chart
circumference. Strip recorders consist of a rotating
cylinder which rolls a strip chart with time. . The variable
axis lies perpendicular to the rolling direction.
The internal working parts of most electronic recorders
are generally the same. The major components are: the
electronic amplifier, the two-phase servo motor, the gear train,
68
-------
and the feedback element (see Figure. 31).
An electronic signal from a flowmeter, transducer, or
other device is amplified to a power level high enough to
drive the servo motor. The servo motor is often a two-phase
reversible type that runs at speeds proportional to input,
and in the established phase direction. Through gearing, the
servo motor positions the pen and the feedback element; the
latter then generates a voltage which is fed back to the
servo motor. . '
Strip recorders have accuracies to within 0.5 percent of
full scale, whereas circular chart recorders usually have
accuracies to within only 1.0 percent. The recorder should
be calibrated while it is connected to the measuring system.
Occasionally the chart speed should be checked during the
test by writing the time on the chart and comparing it with
the time elapsed. Most circular recorders use charts that
are interchangeable with those of other manufacturers.
CONTROL DEVICES
Flowmeters and pressure measuring instruments are often
accompanied by valves which are placed downstream to reduce
shock. Elaborate systems can be designed to automatically
shut down flow when pressure, flow, or temperature exceeds
specified limits. An automatic shut-off device, called an
actuator can be connected to a valve and set to operate only
when an instrument transmitter sends a signal at a special
frequency.
69 ;
-------
Figure 31.
Block Diagram of the Working Components
of an Electronic Recorder (BIF, 1975).
POINTER
INPUT
DIFFERENTIAL
AMPLIFIER
70
-------
Valves are also used frequently to protect gauges and
flowmeters from freezing or corroding by separating the in-
strument from the system. An operator may have separate
lines that contain the measuring devices. A gauge or meter
may 'be taken off of the line and kept indoors until testing
is required. Both valves and actuators are discussed brief.ly
in the following pages.
VALVES
Valves are devices that control fluid flow through
pipes. As with other instruments, valve designs vary for
differing applications. Flow control can be executed by a
simple on-off switch or a gradual throttling device. Some
valves are exclusively used for diversional purposes. The
most common designs are: the ball valve, butterfly valve,
plug valve, globe control valve, knife gate valve, and the
pinch valve. Table 4 lists many functions of several of the
valve designs.
The ball valve is often a hollow sphere, or half sphere
that is tightly fitted inside a valve body. The sphere can
be turned with the poles perpendicular to the flow direction.
The flow is gradually reduced as the valve opening is re-
stricted by the sphere surface. Some balls have a V-shaped
opening to provide smooth throttling throughout the quarter
turn that is necessary to close the valve. Ball valves can
fit pipes as large as 48 inches in diameter and they can be
designed to withstand pressures of up to 800 psi. These
valves are often used for throttling because of their
71
-------
-4
N)
Function
On-Off
Throttling
Diversion
Media
Liquids (clean)
Liquids (dirty)
Liquids (viscous)
Liquids (corrosive)
Slurries (sludge)
Slurries (abrasive)
Slurries (fibrous)
High Pressure Steam
low Pressure Steam
Oases (clean)
Gases (dirty)
Gases (corrosive)
Cry Materials
K>od Service
Valve Characteristics
High now Capacity
High Pressure Drop
Throttling
Low Head Loss
(wide open)
Low Torque/Thrust
High Tenjperature
Cryogenic
Erosion Resistance
Globe Control
Cage
Guided
A
A
D
A
D
D
A
D
D
D
A
A
A
C
A
D
D
A
A
E
A
B
B
D
Top 8t
Bottom
Guided
A
A
D
A
A
A
A
B
B
D
A
B
A
A
A
D
n
A
A
E
A
A
C
B
Top
Guided
A
A
D
A
A
A
A
A
B
D
B
A
A
A
A
0
D
A
B
E
C
A
A
B
TABLE 4
APPLICATIONS OF VARIOUS VALVE DESIGNS
(DeZurik, 1964)
Butterfly
Split Ball High. Rubber 3-Way Gate Pinch
Body Angle 3-Way Valves Pressure Sealed Eccentric 4-Way Valves Valves
A
A
D
A
A
A
A
A
B
D
B
A
A
A
A
D
D
E
C
C
B
B
A
A
D
A
A
A
A
A
A
D
A
A
A
A
A
D
D
E
B
A
D
A
D
A
A
A
B
A
A
C
D
D
B
A
A
B
A
D
D
E
B
C
D
C
B
A
D
A
A
A
A
A
C
A
C
A
A
A
A
D
D
A
A
B
D
C
A
A
C
A
D
B
A
C
D
B
B
A
A
C
A
D
C
A
A
D
D
D
A
A
C
A
B
A
B
B
C
B
D
D
A
B
B
B
B
A
B
D
D
C
A
A
D
D
A
A
A
C
D
A
A
B
A
A
A
A
A
A
B
D
C
A
A
A
B
B
A
A
A
A
A
B
A
D
C
A
A
A
•" D
D
A
A
A
C
A
A
A
D
D
A
A
A
A
C
A
- A
A
A
A
A
' A
' D
C
A
A
A
A
C
A
B
C
D
A
A
A
D
D
C
A
B
A
D
A
A
C
D
D
A
Key:
A - Typical Application
B - toy Be Used
C • Limited Application
D " Not Used
E - Not Applicable
-------
stability in high pressure situations and their resistance
to cavitation; however, they generally tend to cavitate more
at lower pressure drops than other valves (e.g., globe
valves).
The butterfly valve is a circular plate that is as wide
as the inner diameter of the pipe. The valve closes by ro-
tating the plate along a central axis, until it is perpendi-
cular to the flow direction. Most butterfly valves are made
to withstand pressures of approximately 150 psi, and they
rest on a rubber or metal seal when closed. Some that are
designed for pressures of 700 psi are unable to handle abra-
sives; of interest is that butterfly valves can be as large
i'
as 96 inches in diameter.
The plug valve uses a cylindrical plug that functions
like the sphere in ball valves, in that the valve closes on a
quarter turn. One form of plug valve uses an eccentric ac-
tion to help prevent seat scraping and wear. Figure 32 shows
how the valve face moves forward into the rubber seat as it
closes. Plug valves can perform like ball valves at less
cost, although they cannot throttle under high pressures.
Globe-control and knife-gate valves differ from other
valve designs in that they close with a straight downward
motion instead of a quarter turn.
The globe-control valve (see Figure 33) controls flow
between an upper and lower chamber, with a cylindrical or
conical stopper. The conical stoppers are tapered to allow
for smooth throttling while the cylindrical stoppers are
73
-------
Figure 3 2.
The Eccentric Plug Valve. . The plug moves
forward into its seat as it is closing
(DeZurik, 1974).
CLOSED
74
-------
Figure 33.
.Globe Control Valve. Fluid passes through
the valve ,as the plug is raised (C. E.
Invalco, 1984).
FLOW
DIAPHRAGM
PLUG
75
-------
designed for quick on-off switching. Some globe'-control
valves use what is called a cage. Cages are hollow cylinders
(see Figure 134) that allow fluids to pass through slots as
the cage is raised. Some slots are shaped for a certain
throttle characteristic. Globe-control valves are rarely
made for pipes with a diameter of more than 16 inches. Be-
cause of their simple designs, globe-control valves can
handle extreme temperatures and pressures. However, they
create high head losses even when wide open and they cannot
be used with solids or fibrous slurries.
The knife-gate valve is simply a gate door type that de-
scends from the top of the pipe and fits tightly into the
lower inside edge during closing. The valve is inexpensive
and therefore suitable for on-off applications, even though
it is a rather poor throttle. The knife-gate valve is manu-
factured for pipes with diameters of up to 72 inches.
The pinch valve contains two .gates which squeeze togeth-
er from each side of the valve body to shut off flow. The
valve is noted for its ruggedness and its straight unob-
structed flow path, both of which give the valve a wide ap-
plicability. However, pinch valves need, more than a quar-
ter-turn, and then considerable torque in order to be
closed.
In order to divert fluids, three-way and four-way valves
are used. Three-way valves utilize either a rotating plug or
an angled globe-control stopper to divert flow from one chan-
nel to another. Four-way valves place a spinning barrier at
76
-------
Figure 34. Cage Plug (C. E. Invalco, 1984).
77
-------
an intersection of pipes in order to exchange flow.
Cayitation is a phenomenon that can occur when fluids •
suddenly encounter a section of pipe that has a reduced
cross-sectional area, such as a venturi tube or a closing
valve. The pressure is lowest at the thinnest point and it
sometimes drops below the vapor pressure of the liquid
(which is a function of temperature); this condition causes
vapor bubbles which often collapse with great force down-
stream and can cause severe valve and/or pipe damage.
Because cavitation is dependent upon several factors, such as
flow velocity, valve shape,'and pipe diameter, the manufac-.
turer should be consulted for specific instructions and the
known cavitation.coefficients.
ACTUATORS
. Most valves can be equipped with automatic control
devices, called actuators, which can be either pneumatically
i
or electrically powered. Pneumatically powered actuators use
air pressure to force a valve to work with either a piston
traveling inside of a cylinder or a spring-loaded diaphragm.
Other actuators use electric motors. For those valves that
required a quarter-turn, the actuator is connected via levers
or a rack and pinion set-up.
Actuators can be fine-tuned to allow for throttling —
even though most are built to simply open and close valves.
Some globe-control valves are spring-loaded to open automati-
cally at specific line pressures.
78
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APPENDIX A
LIST OF MANUFACTURERS
(This is neither an endorsement of these particular man-
ufacturers nor is it an all-inclusive list of manufacturers of
flowmeters, pressure gauges, and flow control devices.
Manufacturers listed here are those who'responded to the
authors' inquiries.)
Manufacturer
Ametek
U.S. Gauge Division
P.O. Box 152
Sellersville, PA 18960
(215) 257-6531
Badger Meter Mfg. Company
6116 East 15th Street
Tulsa, OK 74112
(918) 836-8411
Basic In Flow (BIF)
1600 Division Road
West Warwick, RI 02893
(215) 839-3551
Brooks Instruments Division
Emerson Electric Company
407 West Vine Street
Hatfield, PA 19440
(215) 362-3500
C. E. Invalco
Combustion Engineering, Inc.
Tulsa, Oklahoma
(918) 834-5671
DeZurik
Sartell, MN 56377
(612) 251-0221
Dresser
Instrument Division
250 East Main Street
Stratford, CT 06497
(203) 378-8281
Fischer and Porter
County Line Road
Warminster, PA 18974
(215) 674-6000
Instrument/Device
Pressure Gauges
Compound Gauges
Others
Flowmeters
Recorders
Flowmeters
Flowmeters
Flowmeters
Pressure Recorders
Valves
Valves
Pressure Gauges
Flowmeters
Deadweight Testers
.Portable Gauge Cali-
brators
Flowmeters
79
-------
APPENDIX A
(continued)
Flow Technology, Inc. .
4250 East Broadway Road
Phoeniz, AZ 85040
(602) 437-1315
Geophysical Research Corporation
6540 East Apache
P.O. Box 15968
Tulsa, OK 74158 •
(918) 834-9600
Hildebrandt Engineering Co., Inc.
7707 Pinemont Drive
Houston, TX 77040
(713) 462-5341
ISCO, Inc... Environmental Division
P.O. Box 82531
Lincoln, NE 68501
(800) 228-4373
Kent Meters
Ocala, FL 32678
(904) 732-4670
Krohne America Inc. Ltd.
11 Dearborn Road
Peabody, MA 01960
(617) 535-6060
Liquid Controls
Wacker Park
North Chicago, IL-60064
(312) 689-2400
Nusonics, Inc. (formerly Mapco)
1800 South Baltimore Avenue
Tulsa, OK 74119
(918) 438-1010
Omega Engineering, Inc.
Box 4047
Stamford, CT 06907
(203) 359-1660
Flowmeters
Piston Provers
Pressure Bombs
Diaphragm Seals
Flowmeters
Samples
Flowmeters
Flowmeters
Flowmeters
Flowmeters
Pressure Trans-
ducers
Electronic Recorders
80
-------
APPENDIX A
(continued)
Paine Instrument, Inc.
2401 South Bayview Street
Seattle, WA 98144
(206) 273-1705
Polysonics
P.O. Box 22432
Houston, TX 77227
(713) 623-2134
Ramapo Instrument Co., Inc,
2 Mars Court
P.O. Box 428
Montville, NJ 07045
(201) 263-8800
Smith Meters
1602 Wagner Avenue
Erie, PA 16512
(814) 899-0661
3D Instruments Inc.
15542 Chemical Lane
Huntington Beach, LA 92649
(714) 894-5351
Tokheim Corporation
Box 260
Fort Wayne, IN 46801
(219) 493-2554
Differential Pressure
Transducers
Flowmeters
Flowmeters
Flowmeters
Gauges
Portable Gauge
Calibrators,
Flowmeters
81
-------
APPENDIX B
GLOSSARY
Actuator. A device that operates a valve.
Annulus. The space between the injection tubing and the well
casing. - .
Bomb. A down-hole pressure recording instrument.
Calibration. The process of setting an instrument into
agreement with an established standard. .
Class I Wells.
1. A well used, by a generator of hazardous waste or an
owner or operator of a hazardous waste management faci-
lity, to inject hazardous waste beneath the lowermost
formation containing, within one-quarter mile of the well
bore, an underground source of drinking water.
2. Another industrial and municipal disposal well which
injects fluids beneath the lowermost formation contain-
ing, within one-quarter mile of the well bore, an
underground source of drinking water.
Class II Wells. A well that is used to inject fluids:
1 .. Which are brought to the surface in connection with
conventional oil or natural gas production and may be
comingled with waste waters .from gas plants which are
classified as a hazardous waste at the time of injection.
2. For enhanced, recovery of oil or natural gas; and
3. For storage of hydrocarbons which are liquids at
standard temperatures and pressures.
Class III Wells. A well that is employed :to inject fluids for
extraction of minerals including:
1. Mining of sulfur by the Frasch process.
2. In-situ production of uranium or other metals; this
category includes only in-situ production from ore bodies
which have not been conventionally mined. Solution mining
of conventional mines such as stopes leaching is included
in Class V.
3. Solution mining of salts or potash.
Class IV Wells.
1. A well used by a generator of hazardous waste or of
radioactive waste, by an owner or operator of a hazardous
waste management facility; or by an owner or operator of a
radioactive waste disposal site to dispose of hazardous
waste or radioactive waste into a formation which is
' within one-quarter mile of the well and it contains an
underground source of drinking water.
82
-------
2. Wells used by generators of hazardous waste or of
radioactive waste, by an owner or operator of a hazardous
waste management facility; or by an owner or operator of a
radioactive waste disposal site to dispose of hazardous
waste or radioactive waste above a formation which within
one-quarter mile of the well contains an underground
source of drinking water. f
3. Wells used by a generator of hazardous waste or an
owner or operator of hazardous waste management facility
to dispose of hazardous waste, which cannot otherwise be
classified as Class I or IV (e.g., wells used to dispose
of hazardous waste into or above a formation which
contains an aquifer which has been exempted pursuant to
(§146.04). .
Class V Wells. An injection well not included in Classes I,
II, III, or IV.
Cryogenics. Pertaining to very low temperatures.
Injection Zone. A geological "formation," groups of forma-
tions, or part of a formation receiving fluids through a
"well."
K^Factor. The number of pulses of a meter per gallons of
fluid measured.
Linearity. The closeness of a calibration curve to a speci-
fied straight line.
Manometer. An instrument for determining the pressure of
gases, vapors,.or liquids.
NBS. National Bureau of Standards, Department of Commerce.
Nutating Meter. A flowmeter that operates on the principle of
the positive displacement of fluid by the wobbling motion of a
piston or disk.
Null. A condition, such as a balance, which results in a
minimum absolute value of output.
Piggable. Able to be cleaned internally with a pig, which is
a scrubber that is guided by cables or water pressures.
Pressure Drop, Loss of Head. The difference in pressure be-
tween the inlet and outlet of a hydraulic device during flow.
PSI (Pounds per Square Inch). The gauge reading of contained
liquids and gases. Sometimes written as PSIG for gauge
pressure alone, or PSIA for gauge plus atmospheric pressure.
Rescaling. Altering an instrument so that it can measure
different ranges or substances.
83
-------
Throttling. The process of turning a valve to produce a
specific flow rate.
Torque. The force required to turn a valve or work a
mechanical flowmeter.
84
-------
APPENDIX C
PUBLICATIONS
Equipment manufacturers publish technical and promotional
materials for their specific flowmeters, pressure instruments
and flow control devices. These publications are generally
available from the equipment manufacturers; their names and
addresses are found in Appendix A. The author of this manual
used manufacturers' literature extensively in preparing this
document. A list of some publications used are as-follows:
Manufacturer
Publication
Badger Meter Manufacturing Co.-Orifice Plates, Bulletin P-400
-Flow Nozzles, Bulletin A-401
-Low Loss Flow Tubes, Bulletin
P-405
-Model MLFT, DMR 110 Z-8977
Basic In Flow
C. E. Invalco
DeZurik
Dresser-Ashcroft
•Electronic Receivers - Speci-
fication Data 257-01.201-1,
1975 •
-Reproduction of Pressure
Differentials as Sensed at
Piezometer Openings
• Instruction Manual - Wand, WCC ~
Series Turbine Flowmeter:
Issue 7 November, 1983
- Industrial W-Series Flowmeter
Installation Instructions
September, 1979
-IVC 251-A2, 1980
-IVC 290-A1, 1984
-Valve Selection Guide Bulletin
12.00-1, January, 1984
-Series 100 Eccentric Valves
Bulletin 1200-1, October, 1974
-Engineering Data Ashcroft -
Gauges: Form 1250-1353-H
-Installation and Maintenance
Manual for Ashcroft Type 1305
Dual Range Deadweight Tester
and Type 1327 Portable Test
Pump: Form Number 250-1526-A
-Pressure, Temperature, Control
Instrument Ordering Handbook,
Bulletin OH-1
85
-------
Manufacturer
Publication
Dresser-Roots
Fischer and Porter
Flow Technology Inc.
Geophysical Research Corp.
Hildebrandt Engineering Co.,
Inc.
Krohne America Ind. Ltd,
Liquid Controls
Mapco
Omega Engineering, Inc.
Paine Instruments, Inc.
Ramapo Instrument Co., Inc,
Smith Meters
-Meters: Bulletin MR-781
-Technical Information, 10LV-6,
May, 1983
-Flow Transfer .Kit Model FT -
AFT-4-CF Bulletin FTK 744
-Amerada RPG-3 and RPG-4 Gauge
Operator's Manual, 1983
-Diaphragm Seal Protectors -
Description, Operation, and
Application, 1983
-Turbine Water Meters, Bulletin
No: IND-476
-Installation Instructions:
INS-6004
-Positive Displacement Water
Meters: Bulletin No. IND-376
-Installation/Start-up Instruc-
tions: INS-0001-DOC
-Krohne Float Type Flowmeters
Product Guide 1
-Autoflux Magnetic - Inductive
Flowmeters Product Guide 3
-Meters and Accessories, Cata-
log 102 C, 1983
-Instruction Manual, Model 9000
Nusonics Flowmeter, Publica-
tion #ESD-611, June, 1979
-Instruction Manual, Model 1181
Doppler Flowmeter; Publication
#ESD-623, December, 1981
-Pressure and Strain Measure-
ment Handbook, 1984
-Brochure EPC-83-1: Price
Schedule EPP-84-1
-Form GP-3, April, 1983
-Technical Paper 101A, 1977
-Technical Paper 103A, 1977
-Compatibility Manual Bulletin
1822
86
-------
Manufacturer
Publication
3D Instruments, Inc.
Tokheim Meters
-Form No. 3D-2001, 1981
-Advanced Design Customized
Metering Systems: Bulletin No.
2610-AR
87
-------
REFERENCES
Chilton's Co. Chilton's Instruments and Control Systems.
Volume 49, Radnor, PA., December, 1976.
Considine, D.M. Process Instruments Controls' Handbook. 2nd
edition. McGraw Hill Book Co., New York, NY., 1974.
Cook, R.R. and Strongman, John R. "New Displacer Piston Sensing
System Promises More Accurate Meter Proving." Oil and Gas
Journal. Volume 81, p.p. 55-8, November 21, 1984.
Ginesi, D. and Greby, G. "A Comparison of Performance Features
vs. Economic Costs." Proceedings of the ISA 85 International
Conference. Volume 40, Part 2, October, 1985.
Halliday, David and Resnick, Robert. The Fundamentals of
Physics. John Wiley and Sons, New York, NY., 1981.
Halmi, D. "Practical Guide to the Evaluation of the Metering
Performance of Differential Procedures." Mechanical Society of
Mechanical Engineers. Paper 72-WA/FM-2, 1976.
Matthews, L.S. and Russell, D.G. Pressure Buildup and Flow
Tests in Wells. Monograph Series. Society of Petroleum Eng-
ineers of AIME. Dallas, TX., 1967.
Miller, R.W. Flow Measurement Handbook. McGraw Hill Co., New
York, NY. , 1983. . . • •
Reason, J, "Special Purpose Flowmeters Offer Better Accuracy,
Range, Linearity." Power,, March, 1983.
Welge, E.A. Testing Oil and Gas Wells for Water Shutoff with a
Formation Tester. California Division of Oil and Gas,
Sacramento, CA., 1981.
88
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CHECKLIST FOR FLOW MEASUREMENT INSPECTION
Prepared By:
Facility:
A. General
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A 3,
Yes No N/A 4,
Yes No N/A 5,
Yes No N/A 6,
Date:
Wellf:
(a) Is primary flow measuring device pro-
perly installed and maintained?
(b) Is there a straight length of pipe be-
fore and after the flowmeter of at least
5 to 20 diameters? This depends on the
type of flowmeter and the ratio of pipe
diameter to throat diameter. Also, the.
introduction of straightening vanes may
reduce this requirement.
(c) If a magnetic flowmeter is used, check
for electric noise (interference) in its
proximity and that the unit is properly
grounded.*
(d) Is the full pipe requirement met?
Flow records are properly kept.
(a) Are records of flow measurement re-
corded in a bound numbered log book?
(b) Are all charts maintained in a file?
(c) Are all calibration data entered in
the log book? .
Are sharp drops or increases in flow
values accounted for?
Is actual flow measured?
Are secondary instruments (totalizers,
recorders, etc.) properly operated and
maintained?
Are appropriate spare parts stocked or is
service available?
*Electrical noise can sometimes be detected by erratic opera-
tion of the flowmeter's output. Another indication is the
flowmeter location in the proximity of large motors, power
lines, welding machines, and other high electrical field
generating devices.
89
-------
B. Flowmeter
1. Type of flowmeter used:
2. Show on the back a "diagram of flowmeter
placement in the system. Indicate the
direction of.flow, the vertical height
relationship of the source, outfall, and
measuring .meter. Give all dimensions in pipe
diameters.
3. Is meter installed correctly?
(a) If magnetic flowmeter is used, it
should be installed in an ascending
column, to reduce air bubbles and assure
full pipe flow.
(b) If a differential pressure meter such as
venturi is used, it should be installed
in a horizontal plane so that high
pressure tap is on the inlet of flow and
taps are horizontal sloping slightly
downward with facilities for cleaning
taps.
4. Flow range to be measured:
Yes No N/A 5. Is flow measurement equipment adequate to
handle expected ranges of flow values?
6. What are the most common problems that the
operator has had with the flowmeter? De-
scribe: .
.7. Flowmeter flow rate: mgd; totali-
zer flow rate: mgd; error: %
8. Permit projected rate of injection:
gal./day
Yes No N/A 9. Is flow totalizer properly calibrated?
10. Frequency of routine inspection by trained
operator: / month
11. Frequency of maintenance inspections by
facility personnel: / year
12. Frequency of flowmeter calibration:
13. Indicator of correct operation: redundant
flowmeters auxiliary flowmeters
pressure readings other_
power usage of pumps
90
-------
14. Indicators of proper Quality Assurance:
redundant flowmeters frequent recal-
ibrations other
PRESSURE GAUGE INSPECTION CHECKLIST
Pressure Gauges
Yes No N/A 1.. Is Bourdon tube gauge protected from cor-
rosion and freezing?
Yes No N/A 2. Is pressure reading relatively constant?
(i.e., absence of rapid pointer movement due
to pulsating pressure or pipeline vibration)
Yes No N/A 3. Are gauge materials suitable for the media
monitored?
Yes No N/A 4. Is a pressure transducer properly install-
ed?
5. Date gauge last calibrated: ;
6. Method of calibration:
Yes No N/A 7. Is the measuring range twice the operating
range or less?
Yes No N/A 8. Is the gauge retarded?
Pressure Recorders
Yes No N/A 1. Are pressure recorders properly installed?
(e.g., chart protected from weather, etc.)
Yes No N/A 2. Are pressure recorders operational? (e.g.
ink, charts moving, etc.)
Yes No N/A 3. Is back-up gauge provided?
Yes No N/A 4. Do back-up gauge pressure and recorded
pressure agree?
Yes No N/A 5. Is the measuring range twice the operating
range or less?
91
-------
CHECKLIST FOR FLOW MEASUREMENT, OPERATOR'S FORM
Prepared By:
Facility:
A. General
Yes No N/A
Yes No N/A
Yes' No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No . N/A
Yes No N/A
Date:
Well#:
1. (a) Type of primary flow measurement de-
vice.
(b) .Is there a straight length of pipe be-
fore and after the flowmeter of at least 5
to 20 diameters? This depends on the type
of flowmeter and the ratio of pipe
diameter to throat diameter. (Also, the
introduction of straightening vanes may
reduce this requirement.)
(c) If a magnetic flowmeter is used, is the
unit properly grounded?*
(d) Is the pipe flowing free?
2. Flow records.
(a) Are records of flow measurement record-
ed in a bound numbered log book?
(b) Are all charts maintained in a file?
(c) Are all calibration data entered in the'
log book?
3. Are sharp drops or increases in flow values
accounted for?
4. Is actual flow measured?
factor. Other? ._
If not indicate
Are secondary instruments (totalizers,
recorders , etc . ) properly operated and main-
tained?
Are appropriate spare parts stocked?
list.
a. _ ,
b.
c.
d. _ ^_
e. _
f. _ • _ ^
Please
*Electrical noise can sometimes be detected by erratic ope-
ration of the flowmeterfs output. Another indication is the
flowmeter location in the proximity of large motors, power •
lines, welding machines, and other high electrical field
generating devices.
92
-------
B. Flowmeter
1. Type of flowmeter used:
2. Note on diagram flowmeter placement in the
system; observe the direction of flow, the
vertical height relationship of the source,
'outfall, and measuring meter. Give all
dimensions in pipe diameters.
Yes No N/A 3. Is meter installed correctly?
(a) If a magnetic 'flowmeter is used, it
should be installed in an ascending
column to reduce air bubbles and assure
full pipe flow. '•
(b) If a differential pressure meter such as
venturi is used, it should be installed
in a horizontal plane so that high
pressure tap is on the inlet of flow and
taps are horizontal sloping slightly
downward with facilities for cleaning
taps.
4. Flow range to be measured:
Indicate criteria for selecting flow range.
6. What are the most common problems with the
flowmeter? ;
7. Flowmeter flow rate: • mgd; totalizer
flow rate: mgd; error %
8. -Permit projected rate of inspection:
Yes No N/A 9. Is flow totalizer properly calibrated?
gal./day
10. Frequency of routine inspection by trained
Operator: , / Month
93
-------
PRESSURE GAUGE OPERATOR'S CHECKLIST.
Pressure Gauges
Yes No N/A 1. Is Bourdon tube gauge protected from cor-
rosion and freezing? Describe briefly
Yes • No N/A 2. Is pressure reading relatively constant
(i.e., absence of rapid pointer movement due
to pulsating pressure or pipeline vibration)?
Yes No N/A 3. Are gauge materials suitable for the media
monitored?
"'* Yes No N/A 4. Is a pressure transducer properly install-
ed?
5. Date gauge last calibrated:
6. Method of calibration:
Yes No N/A 7. Is the measuring range twice the operating
range or less?
Yes No N/A 8. Is the gauge retarded?
Pressure Recorders ' •'
Yes No N/A 1. Are pressure recorders properly installed
(e.g., chart protected from weather, etc.)?
Indicate how
Yes No N/A 2. Are pressure recorders operational (e.g.,-
ink, charts moving, etc.)?
Yes No N/A 3. Is a back-up gauge provided?
Yes No N/A 4. Do back-up gauge pressure and recorded
pressure agree?
Yes No N/A 5. Is the measuring range twice the operating
range or less?
94
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