1、AN AMERICAN NATIONAL STANDARDPressure MeasurementInstruments and Apparatus SupplementASME PTC 19.2-2010Performance Test CodesRevision of ASME/ANSI PTC 19.2-1987 (R2004)INTENTIONALLY LEFT BLANKASME PTC 19.2-2010AN AMERICAN NATIONAL STANDARDRevision of ASME/ANSI PTC 19.2-1987 (R2004)Three Park Avenue
2、New York, NY 10016 USAPressure MeasurementInstruments and Apparatus SupplementPerformance Test CodesDate of Issuance: October 29, 2010This Code will be revised when the Society approves the issuance of a new edition. There will be no addenda issued to PTC 19.22010.ASME issues written replies to inqu
3、iries concerning interpretations of technical aspects of this Code. Periodically certain actions of the ASME PTC Committee may be published as Code Cases. Code Cases and interpretations are published on the ASME Web site under the Committee Pages at http:/cstools.asme.org as they are issued.ASME is
4、the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American National Standards. The Standards Committee that approved the code or standard was balanced to assure that individuals from co
5、mpetent and concerned interests have had an opportunity to participate. The proposed code or standard was made available for public review and comment that provides an opportunity for additional public input from industry, academia, regulatory agencies, and the public-at-large.ASME does not “approve
6、,” “rate,” or “endorse” any item, construction, proprietary device, or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against lia
7、bility for infringement of any applicable letters patent, nor assumes any such liability. Users of a code or standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility.Participation by
8、 federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the established ASME procedures and po
9、licies, which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York,
10、NY 10016-5990Copyright 2010 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.iiiCONTENTSNotice viForeword viiAcknowledgments viiCommittee Roster viiiCorrespondence With the PTC 19.2 Committee . ixSection 1 Object and Scope 11-1 Object . 11-2 Scope 11-3 Uncertainty .
11、1Section 2 Definitions and Terms . 22-1 Introduction 22-2 Definitions 22-3 Units 3 2-4 Dynamic Measurements . 32-5 Use of Control and Operating Instrumentation 4 2-6 Two-Phase Fluid Systems . 5Section 3 Measurement Devices . 63-1 Types of Devices 63-2 Pressure Transmitters and Their Applications 123
12、-3 Elastic Gauges and Their Applications 31Section 4 Calibration and Standards 36Section 5 Measurement Installations . 375-1 Pressure Taps 375-2 Pressure Probes 375-3 Connecting Piping . 475-4 Diaphragm Seals 485-5 Installation Effects . 55Section 6 Uncertainties in Pressure Measurement 576-1 Introd
13、uction 576-2 Combined Standard Uncertainty and Expanded Uncertainty . 576-3 Random Standard Uncertainty 576-4 Using Elemental Random Error Sources 576-5 Systematic Standard Uncertainty 586-6 Propagation of Measurement Uncertainties Into a Result . 586-7 Uncertainty of Measurements (Example) 58Figure
14、s2-2-1 Pressure Terminology . 33-1.1-1 Typical Pressure Devices 73-1.2.1-1 Wheatstone Bridge 73-1.2.1-2 Bonded Strain Gauge 83-1.2.2-1 Typical Deposited-Thin-Film Strain Gauge . 83-1.2.3-1 Typical Piezoresistive Pressure Sensor . 93-1.2.4-1 Typical Variable Capacitive Pressure Sensor . 103-1.2.5-1 P
15、hotoelectric Pressure Sensor 103-1.2.6-1 Inductive Pressure Sensor 113-1.2.7-1 Preferred Schematic Representation of the Linear Variable Differential Transformer (LVDT) 11iv3-1.2.8-1 Piezoelectric Pressure Sensor . 113-1.2.9-1 Pressure Transducer With Vibrating Element . 123-2.1.1-1 Typical Flow Ins
16、tallations . 153-2.1.1-2 Exploded View of Differential-Pressure Transmitter . 163-2.1.2.1-1 Flange-Mounted Transmitters . 173-2.1.2.1-2 Flange Transmitter Mounted Directly to Tank Nozzle 183-2.1.2.1-3 Open-Tank Installation With Remote-Seal Type of Transmitter . 183-2.1.2.2-1 Schematic Diagram of Cl
17、osed-Tank Transmitter Primary . 193-2.1.2.2-2 Closed-Tank Installation, Dry Leg 203-2.1.2.2-3 Closed-Tank Installation, Dry Leg Transmitter Above Datum Line 213-2.1.2.2-4 Closed-Tank Installation, Dry Leg Transmitter Below Datum Line . 223-2.1.2.2-5 Closed-Tank Installation, Wet Leg 233-2.1.2.2-6 Cl
18、osed-Tank Installation, Wet Leg Transmitter Above Datum Line 243-2.1.2.2-7 Closed-Tank Installation, Wet Leg Transmitter Below Datum Line . 253-2.1.2.2-8 Closed-Tank Installation, Dry Leg Transmitter Above Upper Process Tap 263-2.1.2.3-1 Repeater-Type Level-Measurement Device . 263-2.1.3.1-1 Hydrost
19、atic Head Provides One Method of Density Measurement 273-2.1.3.1-2 Differential Hydrostatic Head Increases Sensitivity of Density Measurement 273-2.1.3.2-1 Common Method of Measuring Density of a Process Liquid . 283-2.2.1-1 Typical Drum Water Level 283-3.1.1-1 Bourdon Gauge 293-3.1.1-2 Bourdon Tube
20、s . 303-3.1.2-1 Bellows Gauge 303-3.1.3-1 Slack Diaphragm Gauge . 314-1 Pressure-Measurement Calibration Hierarchy 365-1-1 Tap Geometry . 385-1-2 Pressure-Tap Flow Field . 385-1.1-1 Errors for Different Size Taps in Fully Developed Pipe Flow . 385-1.2-1 Relative Tap Errors as Percent of Dynamic Pres
21、sure 395-2.1.1-1 Impact Tube 405-2.1.1-2 Variation of Total Pressure Indication With Angle of Attack and Geometry for Pitot Tubes 415-2.1.2-1 Keil Probe 425-2.1.2-2 Total Pressure Location on a Cylinder in a Flow Field 425-2.2.1-1 Static Tube . 425-2.2.1-2 Pitot-Static Tube . 435-2.2.2-1 Cylindrical
22、 Probe, Principle of Operation 435-2.2.2-2 Wedge-Type Probe . 445-2.2.2-3 Spherical- and Cone-Type Probes . 445-2.2.3-1 Basket Probe . 455-2.2.3-2 Alternate Basket Probe 455-2.2.4-1 Magnitude of Probe-Blockage Effects, Pressure Error . 465-2.2.4-2 Magnitude of Probe-Blockage Effects, Mach Number . 4
23、75-4.3-1 Seal Assembled With Capillary . 495-4.3-2 Diaphragm Seals and In-Line Diaphragm Seals Installed . 495-4.3-3 Diaphragm Seals and Probe Seal Installed 505-4.3-4 Threaded Diaphragm Seal 505-4.3-5 Flanged Diaphragm Seals . 505-4.3-6 Integral Flange and Diaphragm Seal 515-4.3-7 Separate Flange a
24、nd Diaphragm Seal . 515-4.3-8 Pancake Diaphragm Seal With Capillary Connection . 515-4.3-9 Pancake Diaphragm Seal Installed 525-4.3-10 Flange Extension 525-4.3-11 Pancake Extension . 535-4.7-1 Vapor Pressure Curve of a Fill-Fluid 545-4.9-1 Response Time . 555-4.10-1 Installation Consideration of Pre
25、ssure Instrument and Diaphragm Seals 56vTables2-3-1 Pressure Conversion Factors 43-1.3-1 Pressure Instrument Summary 133-2.1.2.2-1 Seal-Fluid Selection Chart 193-2.1.2.2-2 Type of Calibration Required for Various Transmitter Applications 243-2.1.3.2-1 Variations in Density for Different Fluids 256-7
26、-1 Uncertainty Due to Random Error 596-7-2 Throttle-Pressure Uncertainties . 596-7-3 Exhaust-Pressure Uncertainties . 596-7-4 Condensate-Flow Uncertainties 59Form3-3.6-1 Recording of Gauge-Test Data Sample . 35Nonmandatory AppendicesA Piston Gauges . 61B Manometers 67C Low-Absolute-Pressure (Vacuum)
27、 Instruments . 72D References and Bibliography . 82viNOTICEAll Performance Test Codes must adhere to the requirements of ASME PTC 1, General Instructions. The following information is based on that document and is included here for emphasis and for the convenience of the user of the Supplement. It i
28、s expected that the Code user is fully cognizant of Sections 1 and 3 of ASME PTC 1 and has read them prior to applying this Supplement. ASME Performance Test Codes provide test procedures that yield results of the highest level of accuracy consistent with the best engineering knowledge and practice
29、currently available. They were developed by balanced committees representing all concerned interests and specify procedures, instrumentation, equipment-operating requirements, cal-culation methods, and uncertainty analysis. When tests are run in accordance with a Code, the test results themselves, w
30、ithout adjustment for uncertainty, yield the best available indication of the actual performance of the tested equipment. ASME Performance Test Codes do not specify means to compare those results to contractual guarantees. Therefore, it is recommended that the parties to a commercial test agree befo
31、re starting the test and preferably before signing the contract on the method to be used for comparing the test results to the contractual guarantees. It is beyond the scope of any Code to determine or interpret how such comparisons shall be made.viiFOREWORDThis Instruments and Apparatus Supplement
32、to The American Society of Mechanical Engineers (ASME) Performance Test Codes (PTC) 19 Series provides information on instrumentation and associated procedures for tests involving measurement of pressure. It is intended to promote results consistent with the best engineering knowledge and practice i
33、n industry.The object and scope of any test should be agreed upon in writing by all parties to the test prior to the test.ASME PTC 2, Definitions and Values Code and ASME PTC 19.1, Test Uncertainty may be especially useful references when using this Supplement.The previous Supplement replaced an old
34、er version published in 1964. The previous edition was approved by the Board on Performance Test Codes on September 23, 1986, and adopted by the American National Standard Institute (ANSI) as an American National Standard on August 25, 1987.Subsequent to the 1987 revision, the PTC 19.2 Committee was
35、 reactivated to work on the current revision. This revision uses updated pressure-measurement technologies. Obsolete or rarely used pressure-measuring devices were deleted, resulting in a substantially reduced number of pressure-measurement devices. Some of the less frequently used field devices, su
36、ch as manometers and piston gauges, were moved to the two appendices.This edition of PTC 19.2, Pressure Measurement was approved by the PTC Standards Committee on December 18, 2009, and approved and adopted as a Standard practice of the Society by action of the Board on Standardization and Testing o
37、n January 19, 2010. It was also approved as an American National Standard, by the ANSI Board of Standards Review, on April 22, 2010.ACKNOWLEDGMENTSThe Committee gratefully acknowledges the contribution and leadership role of Charles Doran.viiiASME PTC COMMITTEEPerformance Test Codes(The following is
38、 the roster of the Committee at the time of approval of this Code.)STANDARDS COMMITTEE OFFICERSM. P. McHale, ChairJ. R. Friedman, Vice ChairJ. H. Karian, SecretarySTANDARDS COMMITTEE PERSONNELP. G. Albert, General Electric Co. S. J. Korellis, Dynegy GenerationR. P. Allen, Consultant M. P. McHale, Mc
39、Hale however, they should not contain proprietary names or information.Requests that are not in this format will be rewritten in this format by the Committee prior to being answered, which may inadvertently change the intent of the original request.ASME procedures provide for reconsideration of any
40、interpretation when or if additional information that might affect an interpretation is available. Further, persons aggrieved by an interpretation may appeal to the cognizant ASME Committee. ASME does not “approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activ
41、ity.Attending Committee Meetings. The PTC 19.2 Standards Committee holds meetings, which are open to the pub-lic. Persons wishing to attend any meeting or telephone conference should contact the Secretary of the PTC 19.2 Standards Committee.xINTENTIONALLY LEFT BLANKASME PTC 19.2-20101Section 1Object
42、 and Scope1-1 OBJECTThe object of this Supplement is to give instructions and guidance for the accurate determination of pressure values in support of the ASME Performance Test Codes. The choice of method, instruments, required calcula-tions, and corrections to be applied depends on the pur-pose of
43、the measurement, the allowable uncertainty, and the characteristics of the equipment being tested. 1-2 SCOPEThe methods for pressure measurement and the pro-tocols used for data transmission are provided in this Supplement. Guidance is given for setting up the instru-mentation and determining the un
44、certainty of the meas-urement. Information regarding the instrument type, design, applicable pressure range, accuracy, output, and relative cost is provided.Information on pressure-measuring devices that are not normally used in field environments is given in the Nonmandatory Appendices A (Piston Ga
45、uges), B (Manometers), and C Low-Absolute-Pressure (Vacuum) Instruments. 1-3 UNCERTAINTYThe methods provided in this Supplement are designed to assist in the evaluation of measurement uncertainty based on current technology and engineering knowledge, taking into account published instrumentation spe
46、cifica-tions and measurement and application techniques. This Supplement provides guidance in the use of methods to establish the pressure-measurement uncertainty.ASME PTC 19.2-20102Section 2Definitions and Terms2-1 INTRODUCTIONThe thermodynamic state of a simple fluid is specified by two independen
47、t properties. In experiments involv-ing fluids, pressure is customarily selected as one of the properties to be measured. Pressure measurements are also important in systems involving flowing fluids as an indirect means of measuring velocity and flow rate.Relevant static pressures span a large range
48、 of val-ues. Because of associated dynamic-pressure meas-urement problems, pressure-measurement systems vary greatly in complexity and include a large number of different devices.Section 2 covers the definitions of pressure, funda-mental thermodynamic and fluid-mechanic concepts of pressure, pressur
49、e units and conversion among different units, pressure considerations in and pres-sure relations for flowing fluids, and the use of exist-ing installed instrumentation in equipment tests.2-2 DEFINITIONSaccuracy: the closeness of agreement between a meas-ured value and the true value. Since accuracy varies with measurement device type and the manufacturer, the manufacturer should be consulted for their precise definition. energy relationships: the steady-state microscopic one-dimensional conservation of energy equation (along a
