1、Designation: F2070 00 (Reapproved 2017) An American National StandardStandard Specification forTransducers, Pressure and Differential, Pressure, Electricaland Fiber-Optic1This standard is issued under the fixed designation F2070; the number immediately following the designation indicates the year of
2、original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements for pressureand
3、differential pressure transducers for general applications.1.2 Special requirements for naval shipboard applicationsare included in Supplementary Requirements S1, S2, and S3.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions t
4、o inch-pound units that are provided for informa-tion only and are not considered standard. Where informationis to be specified, it shall be stated in SI units.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the use
5、r of this standard to establish appro-priate safety, health and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in t
6、he Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3951 Practice for Commercial Packaging2.2 ANSI/ISA Standards:3ANSI/ISA S3
7、7.1 Electrical Transducer Nomenclature andTerminology2.3 ISO Standards:4ISO 9001 Quality SystemModel for Quality Assurance inDesign/Development, Production, Installation, and Ser-vicing3. Terminology3.1 Terms marked with “ANSI/ISA S37.1” are taken di-rectly from ANSI/ISA S37.1 (R-1982) and are inclu
8、ded for theconvenience of the user.3.2 Definitions:3.2.1 Terminology consistent with ANSI/ISA S37.1 shallapply, except as modified by the definitions listed as follows:3.2.2 absolute pressure, npressure measured relative tozero pressure (vacuum). ANSI/ISA S37.13.2.3 ambient conditions, nconditions s
9、uch as pressureand temperature of the medium surrounding the case of thetransducer. ANSI/ISA S37.13.2.4 burst pressure, nthe maximum pressure applied tothe transducer sensing element without rupture of the sensingelement or transducer case as specified.3.2.5 calibration, nthe test during which known
10、 values ofmeasurands are applied to the transducer and correspondingoutput readings are recorded under specified conditions.ANSI/ISA S37.13.2.6 common mode pressure, nthe common mode pres-sure is static line pressure applied simultaneously to bothpressure sides of the transducer for the differential
11、 pressuretransducer only.3.2.7 differential pressure, nthe difference in pressurebetween two points of measurement. ANSI/ISA S37.13.2.8 environmental conditions, nspecified externalconditions, such as shock, vibration, and temperature, to whicha transducer may be exposed during shipping, storage,han
12、dling, and operation. ANSI/ISA S37.13.2.9 error, nthe algebraic difference between the indi-cated value and the true value of the measurand.ANSI/ISA S37.11This specification is under the jurisdiction of ASTM Committee F25 on Shipsand Marine Technology and is the direct responsibility of Subcommittee
13、 F25.10 onElectrical.Current edition approved Aug. 1, 2017. Published August 2017. Originallyapproved in 2000. Last previous edition approved in 2011 as F2070 00 (2011).DOI: 10.1520/F2070-00R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s
14、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from International Organizati
15、on for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was develope
16、d in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.10 fiber-optic pre
17、ssure transducer, na device thatconverts fluid pressure, by means of changes in fiber-opticproperties, to an output that is a function of the appliedmeasurand. The fiber-optic pressure transducer normally con-sists of a sensor head, optoelectronics module, and connector-ized fiber-optic cable.3.2.11
18、 hysteresis, nthe maximum difference in output, atany measurand value within the specified range, when thevalue is approached first with increasing and then with decreas-ing measurand. ANSI/ISA S37.13.2.12 insulation resistance, nthe resistance measuredbetween insulated portions of a transducer and
19、between theinsulated portions of a transducer and ground when a specifieddc voltage is applied under specified conditions.3.2.13 line pressure, nthe pressure relative to which adifferential pressure transducer measures pressure.ANSI/ISA S37.13.2.14 operating environmental conditions, n environ-menta
20、l conditions during exposure to which a transducer mustperform in some specified manner.ANSI/ISA S37.13.2.15 optical, adjinvolving the use of light-sensitivedevices to acquire information.3.2.16 optical fiber, na very thin filament or fiber, made ofdielectric materials, that is enclosed by material
21、of lower indexof refraction and transmits light throughout its length byinternal reflections.3.2.17 optoelectronics module, na component of the fiber-optic pressure transducer that contains the optical source anddetector, and signal conditioner devices necessary to convertthe sensed pressure to the
22、specified output signal.3.2.18 output, nelectrical or numerical quantity, producedby a transducer or measurement system, that is a function ofthe applied measurand.3.2.19 overpressure, nthe maximum magnitude of mea-surand that can be applied to a transducer without causing achange in performance bey
23、ond the specified tolerance.3.2.20 pressure cycling, nthe specified minimum numberof specified periodic pressure changes over which a transducerwill operate and meet the specified performance.3.2.21 pressure rating, nthe maximum allowable appliedpressure of a differential pressure transducer.3.2.22
24、process medium, nthe measured fluid (measurand)that comes in contact with the sensing element.3.2.23 range, nmeasurand values, over which a trans-ducer is intended to measure, specified by their upper andlower limits. ANSI/ISA S37.13.2.24 repeatability, nability of a transducer to reproduceoutput re
25、adings when the same measurand value is applied toit consecutively, under the same conditions, and in the samedirection. ANSI/ISA S37.13.2.25 response, nthe measured output of a transducer toa specified change in measurand.3.2.26 ripple, nthe peak-to-peak ac component of the dcoutput.3.2.27 sensing
26、element, nthat part of the transducer thatresponds directly to the measurand. ANSI/ISA S37.13.2.28 sensitivity factor, nthe ratio of the change intransducer output to a change in the value of the measurand.3.2.29 sensor head, nthe transduction element of thefiber-optic pressure transducer that detec
27、ts fluid pressure bymeans of changes in optical properties.3.2.30 signal conditioner, nan electronic device thatmakes the output signal from a transduction element compat-ible with a readout system.3.2.31 static error band, nstatic error band is the maxi-mum deviation from a straight line drawn thro
28、ugh the coordi-nates of the lower range limit at specified transducer output,and the upper range limit at specified transducer outputexpressed in percent of transducer span.3.2.32 transducer, ndevice that provides a usable outputin response to a specified measurand. ANSI/ISA S37.13.2.33 wetted parts
29、, ntransducer components with at leastone surface in direct contact with the process medium.4. Classification4.1 DesignationMost transducer manufacturers use desig-nations or systematic numbering or identifying codes. Onceunderstood, these designations could aid the purchaser inquickly identifying t
30、he transducer type, range, application, andother parameters.4.2 DesignPressure transducers typically consist of asensing element that is in contact with the process medium anda transduction element that modifies the signal from thesensing element to produce an electrical or optical output.Some parts
31、 of the transducer may be hermetically sealed ifthose parts are sensitive to and may be exposed to moisture.Pressure connections must be threaded with appropriate fittingsto connect the transducer to standard pipe fittings or to otherappropriate leak-proof fittings. The output cable must besecurely
32、fastened to the body of the transducer. A variety ofsensing elements are used in pressure transducers. The mostcommon elements are diaphragms, bellows, capsules, Bourdontubes, and piezoelectric crystals. The function of the sensingelement is to produce a measurable response to appliedpressure or vac
33、uum. The response may be sensed directly onthe element or a separate sensor may be used to detect elementresponse. The following is a brief introduction to the majorpressure sensing technology design categories.4.2.1 Electrical Pressure Transducers:4.2.1.1 Differential Transformer TransducerLinear v
34、ari-able differential transformers (LVDT) are variable reluctancedevices. Pressure-induced sensor movement, usually transmit-ted through a mechanical linkage, moves a core within adifferential transformer. Sensors are most commonly bellows,capsules, or Bourdon tubes. The movement of the core withint
35、he differential transformer results in a change in reluctancethat translates to a voltage output. An amplifying mechanicallinkage may be used to obtain adequate core movement.F2070 00 (2017)24.2.1.2 Potentiometric TransducerPressure-inducedmovement of the sensing element causes movement of apotentio
36、meter wiper resulting in a change in resistance whichtranslates to a voltage output. A bellows or Bourdon tube iscommonly used as the sensing element. An amplifying me-chanical linkage may be used to obtain adequate wipermovement.4.2.1.3 Strain Gage TransducerTypical strain gage pres-sure transducer
37、s convert a pressure into a change in resistancedue to strain which translates to a relative voltage output.Pressure-induced movement in the sensing element deformsstrain elements. The strain elements of a typical strain gagepressure transducer are active arms of a Wheatstone Bridgearrangement. As p
38、ressure increases, the bridge becomes elec-trically unbalanced as a result of the deformation of the strainelements providing a change in voltage output.4.2.1.4 Variable Capacitance TransducerVariable capaci-tance pressure transducers sense changes in capacitance withchanges in pressure. Typically,
39、a diaphragm is positionedbetween two stator plates. Pressure-induced diaphragm deflec-tion changes the circuit capacitance, which is detected andtranslated into a change in voltage output.4.2.1.5 Variable Reluctance TransducerVariable reluc-tance pressure transducers sense changes in reluctance with
40、changes in pressure. Typically, a diaphragm is positionedbetween two ferric core coil sensors that when excited producea magnetic field. Pressure-induced diaphragm deflectionchanges the reluctance, which is detected and translated to achange in voltage output.4.2.1.6 Piezoelectric TransducerPiezoele
41、ctric transducersconsist of crystals made of quartz, tourmaline, or ceramicmaterial. Pressure-induced changes in crystal electrical prop-erties cause the crystal to produce an electrical output which isdetected and translated to a change in voltage output.4.2.2 Fiber-Optic Pressure Transducers:4.2.2
42、.1 Fabry-Perot InterferometerFabry-Perot interfer-ometers (FPI) consist of two mirrors facing each other, thespace between the mirrors being called the cavity length. Lightreflected in the FPI is wavelength modulated in exact accor-dance with the cavity length. Pressure-induced movement ofone of the
43、 mirrors causes a measurable change in cavity lengthand a phase change in the reflected light signal. This change isoptically detected and processed.4.2.2.2 Bragg Grating InterferometerA Bragg grating iscontained in a section about 1 cm long and acts as a narrowband filter that detects variation in
44、the optical properties of thefiber. When the fiber is illuminated with an ordinary lightsource such as an LED, only a narrow band of light will bereflected back from the grating section of the fiber. If a pressureis applied to the grating section of the fiber, the grating periodchanges, and hence, t
45、he wavelength of the reflected light,which can be measured.4.2.2.3 Quartz ResonatorsTypically, a pair of quartz reso-nators are inside the pressure transducer. These are excited bythe incoming optical signal. One resonator is load-sensitive andvibrates at a frequency determined by the applied pressu
46、re. Thesecond resonator vibrates at a frequency that varies with theinternal temperature of the transducer. Optical frequency sig-nals from the resonators are transmitted back to the optoelec-tronics interface unit. The interface unit provides an output oftemperature-compensated pressure.4.2.2.4 Mic
47、romachined Membrane/DiaphragmDeflectionThe sensing element is made on a silicon substrateusing photolithographic micromachining.The deflection of thismicromachined membrane is detected and measured usinglight. The light is delivered to the sensor head through anoptical fiber. The light returning fro
48、m the membrane is propor-tional to the pressure deflection of the membrane and isdelivered back to a detector through an optical fiber. The fiberand the sensor head are packaged within a thin tubing.4.3 TypesThe following are common types of pressureand differential pressure transducers: pressure, d
49、ifferential;pressure (gage, absolute and sealed); pressure, vacuum; andpressure, compound.4.4 Process MediumThe following are the most commontypes of process media: freshwater, oil, condensate, steam,nitrogen and other inert gases, seawater, flue gas and ammonia,and oxygen.4.5 ApplicationThe following is provided as a generalcomparison of different types of transducers and considerationsfor application.4.5.1 LVDT TransducerThe sensor element may becomecomplicated depending on the amount of motion required forcore displacement. Caref
