1、Designation:D796221Standard Practice forDetermination of Minimum Immersion Depth andAssessment of Temperature Sensor Measurement Drift1This standard is issued under the fixed designation D7962;the number immediately following the designation indicates the year oforiginal adoption or,in the case of r
2、evision,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.Scope*1.1 This practice describes two procedures for use withtemperature measurement devices.Methodology is desc
3、ribedfor determining minimum immersion depth for thermalsensors,in particular RTDs or similar temperature sensors.Included is a procedure for consistently preparing a referencebath for the purpose of monitoring measurement drift ofthermal sensors such as liquid-in-glass or digital contactthermometer
4、s.1.2 This practice focuses on temperature measurement driftin a laboratory.If the user requires greater measurementaccuracy,then they should follow the instructions in PracticeE563.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstan
5、dard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use
6、.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to
7、 Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2E563 Practice for Preparation and Use of an Ice-Point Bathas a Reference Temperature3.Terminology3.1 Definitions:3.1.1 digital contact thermometer(DCT),nan electronicdevice consisting of a digital display and associatedtemperature-sensin
8、g probe.3.1.1.1 DiscussionThis device consists of a temperaturesensor connected to a measuring instrument;this instrumentmeasures the temperature-dependent quantity of the sensor,computes the temperature from the measured quantity,andprovides a digital output.This digital output goes to a digitaldis
9、play and/or recording device that may be internal or externalto the device.3.1.1.2 DiscussionThe devices are often referred to as a“digital thermometers,”however the term includes devices thatsense temperature by means other than being in physicalcontact with the media.3.1.1.3 DiscussionPortable ele
10、ctronic thermometers(PET)is an acronym sometimes used to refer to a subset of thedevices covered by this definition.3.1.2 ice-point bath,nphysical system containing ice andwater assembled to realize the ice point as a referencetemperature,or to establish a constant temperature near 0 C.3.1.3 minimum
11、 immersion depth,ndepth that a thermom-etershouldbeimmersed,inauniformtemperatureenvironment,such that further immersion does not produce achange in indicated temperature greater than the specifiedtolerance.4.Summary of Practice4.1 This practice provides a procedure for determiningmeasurement drift
12、of a temperature sensor and a procedure fordetermining the minimum immersion depth of temperaturesensor using an ice bath.4.2 This practice describes a procedure for consistentlypreparing an ice bath that is an intimate mixture of crushed iceor ice particles and water in a thermally insulating vesse
13、l opento the atmosphere.4.2.1 Cautionthe ice and water used to prepare an ice bathshould be made from distilled or deionized water.A bath soprepared can provide a temperature uncertainty of about1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubr
14、icants and is the direct responsibility of Subcom-mittee D02.91 on Coordinating Subcommittee on Thermometry.Current edition approved May 1,2021.Published May 2021.Originallyapproved in 2015.Last previous edition approved in 2017 as D7962 17.DOI:10.1520/D7962-21.2For referenced ASTM standards,visit t
15、he ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr H
16、arbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed 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.160.005 C.If the user needs a more accurate ice point,thenthey should use Practice E563 to prepare the ice bath.5.Sig
