pfs differential flow meter bulletin
TRANSCRIPT
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7/28/2019 Pfs Differential Flow Meter Bulletin
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DOCUMENT NUMBER: 2005-100
2006 Primary Flow Signal, Inc. All Rights Reserved
Primary Flow Signal, Inc.- WORLD HEADQUARTERS800 Wellington Avenue Cranston, RI 02910, USA http://www.primaryflowsignal.com
toll free: 1-877-737-3569 phone: 401-461-6366 fax: 401-461-4450
DIFFERENT IAL FLOW
METER SELECT ION GUIDEPRODUCT BULLETI
Purpose:
Format:
The purpose of this guide is to provide an objective method of selecting the type of differential flow meter that best suits a particularapplication. The comparative information presented is based on 25 years of field experience as well as a wide range of technicalpapers and codes which offer valuable guidance and insight into the performance and characteristics of differential devices.
Each section focuses on a particular flow meter type. Within the section, key characteristics and performance attributes areenumerated. Notes are provided for each section that further elaborate and qualify certain statements, and should be consideredintegral to the presentation and to any conclusions the reader makes with respect to the flow meters considered.
ORIFICE NoLimit
50 to 70percent
+/- 0.50 to+/-1.50**
+/-0.67 ***
Must begreater than
10,000
App roach andDownstream
Required
0.20 through0.75
Acc uracy isadversely affected
by any changein bore edge****
Non-abrasive, clearlow viscosity liquid
or gas
LOW
*Per ASME Fluid Meters;**Depending on bore size (smaller bo res 70%, larger bo res less than 70%);***If in compliance with AGA 3 r equirements;****The accuracy of an orifice plate is in fluenced by any change to the sharpness of its bore edge. This demands regular fieldinspection and replacement if change is noted. Approach and discharge straight piping must comply wit h ASME Fluid Meterrequirements, including need for flow straighteners, if indicated;
MeterType
Line SizeRange
(inches)
Headloss% of
Differential
BasicAcc uracy(% of Total)
Minimumpipe Reynolds
number
RequiredStraightPiping
BetaRange
UsefulService
Life
ServiceFunctional
Limits
CostRange
ORIFICE NoLimit
50 to 70percent
+/- 0.50 to+/-1.50**
+/-0.67 ***
Must begreater than
10,000
App roach andDownstream
Required
0.20 through0.75
Acc uracy isadversely affected
by any changein bore edge****
Non-abrasive, clearlow viscosity liquid
or gas
LOW
*Per ASME Fluid Meters;**Depending on bore size (smaller bores 70%, larger bores less than70%);***If in compliance with AGA 3 requirements;****The accuracy of an orifice plate is influenced by any change to thesharpness of its bore edge. This demands regular field inspection andreplacement if change is not ed. Approach and disc harge straight pipingmust co mply with A SME Fluid Meter requirements, including need for flowstraighteners, if indicated;
MeterType
Line SizeRange
(inches)
Headloss% of
Differential
BasicAcc uracy(% of Total)
Minimumpipe Reynolds
number
RequiredStraightPiping
BetaRange
UsefulService
Life
ServiceFunctional
Limits
CostRange
WEDGEPFS Wedge-
typeTM
WEDGEPFS Wedge-
typeTM
thru
24.0 *
thru
24.0 *
30 to 60percent
30 to 60percent
+/- 2.0 to+/-4.0**
+/- 2.0 to+/-4.0**
Must begreater than
500
Must begreater than
500
Approac h andDownstream
Required
Approac h andDownstream
Required
0.20 through0.5 H/D***
0.20 through0.5 H/D***
Long
Long
Ideal for harsh,high viscosity,liquid, slurry or
gas service
Ideal for harsh,high viscosity,liquid, slurry or
gas service
LOW****
LOW****
*Larger line sizes are available but must be laboratory flow calibrated.**Accuracy stated is standard, non-laboratory flo w calibrated value. Accuracy of +/- 0.50% is possible with laboratory flowcalibration (must include up and down stream piping.)***H/D is the ratio between wedge segment opening (H) and the inside diameter of the meter body (D).****The relative capital cost of dif ferential produci ng flo w meters c an vary. Selection criteria recommending the Wedge metermust emphasize its superior ability to m easure harsh, abrasive, high viscosity, and otherwise difficult service conditions.
*Larger line sizes are available but must be laboratory flow calibrated.**Accuracy stated is standard, non-laboratory flow calibrated value. Accuracy o f +/- 0.50% is possible w ithlaboratory flow calibration (must include up and down st ream piping.)***H/D is the ratio between wedge segment opening (H) and the inside diameter of the meter body (D).****The relative capital cost of differential producing flow m eters can vary. Selection crit eria recommending theWedge meter must emphasize its sup erior ability to measure harsh, abrasive, high visc osity, and otherwisedifficult service conditions.
WEDGEPFS Wedge-
typeTM
ELBOW
thru
24.0 *
1.0to any
line size
30 to 60percent
N/A*
+/- 2.0 to+/-4.0**
+/- 4.0 **
Must begreater than
500
Must begreater than
10,000
Approac h andDownstream
Required
Approac h(Upstream)Required
0.20 through0.5 H/D***
N/A
Long
Long
Ideal for harsh,high viscosity,liquid, slurry or
gas service
Clear liqu idand gas.
LOW****
VERYLOW
*Larger line sizes are available but must be laboratory flow calibrated.** Accuracy stated is standard, non-laboratory flow calibrated value. Accuracy of +/- 0.50% is possible wi th laboratory flow calibration (must includeup and down stream piping.)*** H/D is the ratio between wedge segment opening (H) and the inside diameter of the meter body (D).**** The relative capital c ost of differential producing flow meters can vary. Selection criteria recommending the Wedge meter must emphasize itssuperior ability to m easure harsh, abrasive, high vis cosity, and otherwise difficu lt service conditions .
* The Elbow meter utilizes the headloss created by flowpassing throug h the elbow as a differential pressure signal.This limits th e elbow meter application to flow rate range(s)that can accurately be covered by the secondary instrument(DP transmitter) particularly as regards the low enddifferential pressure. Typically an Elbow m eter useful rangeis 3 or 4 to 1 on flow.
** Per ASME. Better accuracy ca with speciall y machinedelbows and laboratory flow calibration. Repeatability is goodat 0.2% or better.
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7/28/2019 Pfs Differential Flow Meter Bulletin
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DOCUMENT NUMBER: 2005-100
2006 Primary Flow Signal, Inc. All Rights Reserved
Primary Flow Signal, Inc.- WORLD HEADQUARTERS800 Wellington Avenue Cranston, RI 02910, USA http://www.primaryflowsignal.com
toll free: 1-877-737-3569 phone: 401-461-6366 fax: 401-461-4450
DIFFERENT IAL FLOW
METER SELECT ION GUIDEPRODUCT BULLETI
ORIFICE
WEDGEPFS Wedge-
typeTM
NoLimit
thru
24.0 *
50 to 70percent
30 to 60percent
+/- 0.50 to+/-1.50**
+/-0.67 ***
+/- 2.0 to+/-4.0**
Must begreater than
10,000
Must begreater than
500
Approach andDownstream
Required
Approach andDownstream
Required
0.20 through0.75
0.20 through0.5 H/D***
Acc uracy isadversely affected
by any changein bore edge****
Long Ideal for harsh,high viscosity,liquid, slurry or
gas service
LOW
LOW****
*Per ASME Fluid Meters;**Depending on bore size (smaller bor es 70%, larger bor es less than 70%);***If in compliance with AGA 3 requirements;****The accuracy of an orifice plate is inf luenced by any c hange to the sharpness of its bore edge. This demands regular fieldinspection and replacement if change is noted. Approach and discharge straight pipi ng must comply w ith ASME Fluid Meterrequirements, including need for flow straighteners, if indicated;
*Larger line sizes are available but must be laboratory flow calibrated.**Accuracy stated is standard, non-laboratory flo w calibrated value. Accuracy of +/- 0.50% is possib le with laboratory flowcalibration (must include up and do wn stream piping.)***H/D is the ratio between wedge segment opening (H) and the inside diameter of the meter body (D).
****The relative capital cos t of differential producing flow meters c an vary. Selection criteria recommending th e Wedge metermust emphasize its superior ability to measure harsh, abrasive, high viscosity, and otherwise difficult service cond itions.
Line SizeRange
(inches)
Headloss% of
Differential
BasicAcc uracy(% of Total)
Minimumpipe Reynolds
number
RequiredStraightPiping
BetaRange
UsefulService
Life
CostRange
FLOWNOZZLE
CLASSICALVENTURI
Greaterthan2.0
4.0thru
48.0 *
40 to 95percent*
12 to 30percent**
+/- 0.25 to+/-2.00**
+/-1.0 to+/-2.0
Must begreater than
10,000
Must begreater than
100,000
Approach andDownstreamRequired***
Approach on lyRequired
0.20 through0.80***
0.40 through0.80
Medium tolong
Medium***Periodic Tap andannular chambermaintenance i s
required.
Clear liqu ids,gas and steam
MED.to
HIGH
HIGH
*Per ASME, ISO 5167 and MFC-3M-85.** Headloss is a function of Beta ratio; the smaller the Beta thehigher the headloss.*** ASME Classical Venturi meters, by des ign, have annularchambers, and all prior test data referring to these designsincludes the performance effects of t hese chambers. Since theannular chambers are subject to plu gging in contaminatedprocess fluid applications, clear liquids and gases present thebest use of this meter design. Because corrosion may produ ceplugging effects to the annular chamber and impulse taps overtime, as well, useful service life is co ntingent upon material
selection. Periodic maintenance work to remove detritus andplugging is recommended.
Line SizeRange
(inches)
Headloss% of
Differential
BasicAcc uracy(% of Total)
Minimumpipe Reynolds
number
RequiredStraightPiping
BetaRange
UsefulService
Life
CostRange
ServiceFunctional
Limits
Clear Liquids, Gasand steam****
ServiceFunctional
Limits
*Headloss is a function o f bore size. If nozzle is part of a meter run in cluding straightening vane(asrequired by some codes) loop headloss will b e on high side.**Per ASME includin g ASME PTC-6.***Consult ASME and ISA for specific design requirements as function of Beta ratio.****One prominent use of the ASME Nozzle and ASME Nozzle meter run is for steam turbine efficiencytesting as specified by ASME PTC-6.
that a number o f international codes govern use and design of flow nozzles, ASME, ISA andothers. While they cover similar meter embodiments, design parameters and , andstated performance in key areas may differ.
Noterequirements
MeterTypeMeterType
(Continued)(C)2005-Primary Flow Sig nal, Inc.-All right s reserved.
This 24.0 ClassicalVenturi is beingrefurbished in PFSWarwick, RI facility.Only the entrancevestibule and throatsection are shown. Thecomplete flow meter isnearly twice the length
WEDGEPFS Wedge-
typeTM
thru
24.0 *
30 to 60percent
+/- 2.0 to+/-4.0**
Must begreater than
500
Approach andDownstream
Required
0.20 through0.5 H/D***
Long Ideal for harsh,high viscosity,liquid, slurry or
gas service
LOW****
*Larger line sizes are available but must b e laboratory flow calibrated.**Accuracy stated is standard, non-laboratory f low calibrated value. Accuracy of +/- 0.50% is p ossible with laboratory flowcalibration (must include up and do wn stream piping.)***H/D is the ratio between wedge segment opening (H) and the inside diameter of the meter body (D).****The relative capital cos t of differential producing flow meters c an vary. Selection criteria recommending th e Wedge metermust emphasize its superior ability to measure harsh, abrasive, high viscosity, and otherwise difficult service cond itions.
MODIFIEDSHORTFORM
VENTURI
0.50to any
line size
3.50 to10.0
+/- 0.50 * Must begreater than
75,000
App roach(Upstream)Required
0.20 through0.80
Very Long Clear liquid,gas, steam, andcontaminatedline fluid(s).**
MED.
* Modified short form Venturi meters can be madeof any machinable material and in any lin e size. Thebasic accuracy is substantiated by prior laboratoryflow calibrations and there is no effect onperformance as a function o f line size or Beta ratio.+/-0.25% accuracy (or better) is achievable through
individual laboratory flow calibration.
** Modified Short Form Venturi meters can beequipped with sealed diaphragm sensors toeliminate plugging con cerns by suspended solidsin process fluid. Options are available for i n-placecalibration of secondary instrumentation withoutnecessity for line shut-down o r equipment removal.
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7/28/2019 Pfs Differential Flow Meter Bulletin
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DOCUMENT NUMBER: 2005-100
2006 Primary Flow Signal, Inc. All Rights Reserved
Primary Flow Signal, Inc.- WORLD HEADQUARTERS800 Wellington Avenue Cranston, RI 02910, USA http://www.primaryflowsignal.com
toll free: 1-877-737-3569 phone: 401-461-6366 fax: 401-461-4450
DIFFERENT IAL FLOW
METER SELECT ION GUIDEPRODUCT BULLETI
ORIFICE
WEDGEPFS Wedge-
typeTM
NoLimit
thru
24.0*
50 to 70percent
30 to 60percent
+/- 0.50 to+/-1.50**
+/-0.67 ***
+/- 2.0 to+/-4.0**
Must begreater than
10,000
Must begreater than
500
Appro ach andDownstream
Required
Appro ach andDownstream
Required
0.20 through0.75
0.20 through0.5 H/D***
Acc urac y i sadversely affected
by any changein b ore edge****
Long
Non-abrasive, clearlow viscosity liquid
or gas
Ideal for harsh,high viscosity,liquid, slurry or
gas service
LOW
LOW****
*Per ASME Fluid Meters;**Depending on bore size (smaller bores 70%, larger bores l ess than 70%);***If in co mpliance with AGA 3 requi rements;****The accuracy of an orif ice plate is influ enced by any change to the sharpness of its bore edge. Thisdemands regular field inspecti on and replacement if change is noted. Approach and discharge straightpiping m ust comply wi th ASME Fluid Meter requirements, including need for flow st raighteners, if indicated;
*Larger line sizes are available but must be laboratory flo w calibrated.**Accuracy stated is standard, non-laboratory flo w calibrated value. Accuracy of +/- 0.50% is possib le withlaboratory flow calibration (must include up and down stream piping.)***H/D is the ratio between wedge segment opening (H) and the ins ide diameter of the meter body (D).****The relative capital cost of differential produ cing fl ow meters can vary. Selection crit eria recommendingthe Wedge meter must em phasize its superior abil ity to measure harsh, abrasive, high viscosit y, andotherwise difficult service conditions.
MeterType
Line SizeRange
(inches)
Headloss% of
Differential
BasicAccur acy(% of Total)
Minimumpipe Reynolds
number
RequiredStraightPiping
BetaRange
UsefulService
Life
ServiceFunctional
Limits
CostRange
HBX-1
HBX-2ELBOW
0.50to any
line size
0.25t0 any
line size
18 to 25percent
Standardelbow
+/- 0.50*
+/- 2.0*
Must begreater than
6,600
Must begreater than
5,000
Appro ach o nlyRequired
Very sh ortAppro ach
onlyRequired
0.20 through0.80
Any**
Very Long
Very Long
Clear liquids, gasesand steam.
Ideal for l iquid,gas, steam andcontaminated
service
LOW
VERYLOW
*The PFS-X1 was designed to pro vide Venturi meter accuracy, repeatability and l ong service l ife butincludi ng low fl ow rate capability (down t o 6,600 pipe Reynolds number) which cannot be easily achievedusing st andard Venturi meter designs.
**The significant beneficial feature of t he PFS-X1 is that it is not limi ted to 75,000 pipe Reynolds numberlow limi t for const ant accuracy as is the case for the Modified Short Form Venturi desi gn. This results in asignificantly lower flow range-ability of this design while still enjoying high, stable and linear accuracyperformance envelope.
*Laboratory flow c alibration wi ll impro ve meter accuracy to +/-0.25%.
** Reduced bore is specifically designed to develop high diff erentials.NOTE: a variety of tap orientations are utilized depending on the type of service int ended.
MeterType
Line SizeRange
(inches)
Headloss% of
Differential
BasicAccur acy(% of Total)
Minimumpipe Reynolds
number
RequiredStraightPiping
BetaRange
UsefulService
Life
ServiceFunctional
Limits
CostRange
(Continued) (C)2005-Primary Flow Signal, Inc.-All righ ts r eserved
PFS Self Checking Option-Short form Venturi and HBX-1 meters can beequipped with a self checking system that comparestwo independent pressure sources and alarms if thechange exceeds a range limit. The alarm then signalseither a transmitter malfunction or unacceptablechange to the internal geometry of the flow meterrequiring maintenance or corrective action. Thisprevents long term undetected accuracy degradationin critical applications. 64:1applications, and triple
ABRASIVE LINE
FLUID NOT APROBLEM!Novel rectangularVenturi design byPrimary Flow Signal,Inc.
Features removableand replaceablesegment for harsh andabrasive service
PFSFlowMaster-fully integrated secondary metering system
Primary Flow Signal, Inc. Has developed a wide variety of secondary instrumentationmetering systems which can be used with a broad range of differential producer typeflow meter primaries. The selection of equipment that is factory installed, tested andcalibrated is dependent upon the specificrequirements of each application. Single range systems are most frequently used for8:1 flow range applications. Dual range systems are used on 64:1applications, andtriple range systems can be effectively used up to 500:1 applications.
inside a properly sized NEMA 4X enclosure,
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7/28/2019 Pfs Differential Flow Meter Bulletin
4/4
DOCUMENT NUMBER: 2005-100
2006 Primary Flow Signal, Inc. All Rights Reserved
Primary Flow Signal, Inc.- WORLD HEADQUARTERS800 Wellington Avenue Cranston, RI 02910, USA http://www.primaryflowsignal.com
toll free: 1-877-737-3569 phone: 401-461-6366 fax: 401-461-4450
DIFFERENT IAL FLOW
METER SELECT ION GUIDEPRODUCT BULLETI