1、Designation: E77 07E77 14Standard Test Method forInspection and Verification of Thermometers1This standard is issued under the fixed designation E77; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision.Anumber
2、 in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method covers visual and dimensional inspection
3、, test for permanency of pigment, test for bulb stability, inspectionand test for scale accuracy to be used in the verification of liquid-in-glass thermometers as specified in SpecificationSpecificationsE1 and E2251. However, these procedures may be applied to other liquid-in-glass thermometers.2NOT
4、E 1The use of NIST SP250-232 is recommended.1.2 WarningMercury has been designated by EPA and many state agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Cautionshould be take
5、n when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSDS) for details and EPAs website- http:/www.epa.gov/mercury/faq.htm - for additional information. Users should be awarethat selling mercury and/or mercury containing products into your st
6、ate may be prohibited by state law.-1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimita
7、tions prior to use.2. Referenced Documents2.1 ASTM Standards:3E1 Specification for ASTM Liquid-in-Glass ThermometersE344 Terminology Relating to Thermometry and HydrometryE2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids3. Terminology3.1 Definitions:3.1.1 Th
8、e definitions given in Terminology E344 apply. Some that are considered essential to this standard are given below.3.1.2 calibration, nof a thermometer or thermometric system, the set of operations that establish, under specified conditions,the relationship between the values of a thermometric quant
9、ity indicated by a thermometer or thermometric system and thecorresponding values of temperature realized by standards.3.1.2.1 Discussion(1) The result of a calibration permits either the assignment of values of temperature to indicated values of thermometric quantityor determination of corrections
10、with respect to indications. (2)Acalibration may also determine other metrological properties suchas the effect of influence quantities. (3) The result of a calibration may be communicated in a document such as a calibrationcertificate or a calibration report. (4) The term calibration has also been
11、used to refer to the result of the operations, torepresentations of the result, and to the actual relationship between values of the thermometric quantity and temperature.1 This test method is under the jurisdiction of ASTM Committee E20 on Temperature Measurement and is the direct responsibility of
12、 Subcommittee E20.05 onLiquid-in-Glass Thermometers and Hydrometers.Current edition approved Dec. 1, 2007May 1, 2014. Published January 2008September 2014. Originally approved in 1949. Last previous edition approved in 20032007as E77 98E77 07.(2003). DOI: 10.1520/E0077-07.10.1520/E0077-14.2 “Liquid-
13、in-Glass Thermometer Calibration Service,” NIST Special Publication 250-23, 1988, Superintendent of Documents, U.S. Government Printing Office,Washington, DC 20402-9325.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual
14、 Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be te
15、chnically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, P
16、O Box C700, West Conshohocken, PA 19428-2959. United States13.1.3 complete-immersion thermometer, n a liquid-in-glass thermometer, not specified in ASTM documents, designed toindicate temperature correctly when the entire thermometer is exposed to the temperature being measured.3.1.4 partial-immersi
17、on thermometer, n a liquid-in-glass thermometer designed to indicate temperature correctly when thebulb and a specified part of the stem are exposed to the temperature being measured.3.1.5 total-immersion thermometer, na liquid-in-glass thermometer designed to indicate temperature correctly when jus
18、t thatportion of the thermometer containing the liquid is exposed to the temperature being measured.3.2 Definitions of Terms Specific to This Standard:3.2.1 calibration, nthe determination of the indications of a thermometer with respect to temperatures established by astandard resulting in scale co
19、rrections to be applied when maximum accuracy is required.3.2.1 reference point, na temperature at which a thermometer is checked for changes in the bulb volume.3.2.2 verification, nthe process of testing a thermometer for compliance with specifications.3.2.3 verification temperatures, nthe specifie
20、d temperatures at which thermometers are tested for compliance with scale errorlimits.3.2.4 Other descriptions of terms relating to thermometers are included in Sections 3 and 17 of Specification E1.4. Significance and Use4.1 The test method described in this standard will ensure that the thermomete
21、rs listed in SpecificationSpecifications E1 andE2251 will indicate temperatures within the maximum scale errors listed, be compatible with the apparatus, and serve the purposefor which they were designed.Fig. 14.2 Thermometers that do not pass the visual and dimensional inspection tests may give err
22、oneously high or low temperaturereadings, or may not fit into existing equipment used in ASTM methods. If the pigment in the scale etchings washes out or fades,the thermometer will be difficult to read. Improper annealing of the bulb, as determined by the bulb stability test, will result inthermomet
23、er readings rapidly changing with time and use. For accurate temperature measurements the scale readings of thethermometer should be verified as described in this test method.5. Apparatus5.1 Graduated Metal Scales or TemplatesMaximum and minimum specified linear dimensions are measured with graduate
24、dmetal sales and templates on which lines are ruled at suitable distances from reference points corresponding to the maximum andminimum values of the several specified dimensions.5.2 Micrometers and Ring GagesSpecified diameters of ASTM thermometers are checked using micrometers, or moreconveniently
25、 with ring gages consisting of metal plates in which holes have been formed corresponding to the maximum andminimum values of the several specified dimensions. The thickness of such gages should approximate the diameters of the holesto minimize errors resulting from the axis of the thermometer stem
26、being other than normal to the plane of the gage. Whenspecified, diameters may also be checked with conventional snap gages having plane parallel working faces.5.3 ComparatorsComparators are required for verification of scale accuracy of liquid-in-glass thermometers. Suitable typesare described in A
27、ppendix X1.5.4 OvenThe test for permanency of pigment may be conducted with any suitable oven, such as the type shown in Fig. 1.5.5 Metal Block BathsThe bulb stability test may be conducted with a variety of devices. Metal block baths and the salt andtin comparator baths, described in Appendix X1, a
28、re examples of the type of equipment that has been found to be suitable for thispurpose.5.4 Primary Standard ThermometerThe primary standard thermometer in the range from 183 to 630 C (297 to 1166 F)is the platinum-resistance thermometer. Temperatures are not measured directly with this instrument.
29、Its electrical resistance isdetermined by comparison with a standard resistor, using a potentiometer, a Kelvin-type double bridge, or a Wheatstone bridge,(preferably of the Mueller type) or an AC resistance bridge. Temperatures may then be calculated using suitable resistance-temperature equations.
30、In order that it shall be satisfactory for such use, the thermometer should meet the requirement that the ratioof resistances at the steam and ice points shall be greater than 1.3925. More complete information on the construction and use ofprimary standard thermometers may be obtained from NIST SP25
31、0-22.45.5 Secondary Standard Thermometers Secondary standard thermometers are more suitable for routine work, and may be ofvarious types as described below. They are simpler to use than a primary standard thermometer with its accessory equipment, thelatter being capable of an order of precision and
32、accuracy far in excess of that attainable with liquid-in-glass thermometers. Thechoice of a secondary standard will be governed by various factors. The following criteria should, in so far as possible, be satisfied:4 “Platinum Resistance Thermometer Calibrations,” NIST Special Publication 250-22, Su
33、perintendent of Documents, U.S. Government Printing Office, Washington, DC20402-9325.E77 142The standard should be a calibrated thermometer of equal or preferably higher sensitivity than the thermometer to be verified, andit should be capable of giving results of an equal or preferably higher order
34、of accuracy and also of an equal or preferably higherorder of reproducibility or precision. Scale corrections should always be applied in the use of these standards. Secondary standardsmay be of the following types.5.5.1 Direct-Reading Resistance ThermometersDirect-reading resistance thermometers ar
35、e available commercially, are veryconvenient to use, and have the advantage over the primary type that temperature indications are given directly in the instrumentreading.They should be completely recalibrated every 6 to 12 months, depending upon the temperatures of usage. Ice points shouldbe taken
36、every 3 months.5.5.2 Liquid-in-Glass ThermometersLiquid-in-glass thermometers, when used as secondary standards, may be classified intotwo groups, those intended for testing general purpose total or partial-immersion thermometers, and those for testing special usepartial-immersion thermometers.5.5.2
37、.1 Total-Immersion ThermometersIn the case of general purpose total-immersion thermometers, the sensitivity of thethermometers to be tested will govern the choice of standard. For thermometers graduated in 1, 2, or 5 divisions, a set ofwell-made thermometers will be adequate when calibrated and used
38、 with applicable corrections. For fractionally graduatedthermometers a calibrated set of the following thermometers is recommended. Specifications for these ASTM PrecisionThermometers appear in Specification E1.ASTMTher-mometerNumber Range Celsius DivisionsLength,mm62C 38 to +2C 0.1C 38063C 8 to +32
39、C 0.1C 38064C 25 to 55C 0.1C 38065C 50 to 80C 0.1C 38066C 75 to 105C 0.1C 38067C 95 to 155C 0.2C 38068C 145 to 205C 0.2C 38069C 195 to 305C 0.5C 38070C 295 to 405C 0.5C 380ASTMTher-mometerNumber Range Fahrenheit DivisionsLength,mm62F 36 to +35F 0.2F 38063F 18 to 89F 0.2F 38064F 77 to 131F 0.2F 38065
40、F 122 to 176F 0.2F 38066F 167 to 221F 0.2F 38067F 203 to 311F 0.5F 38068F 293 to 401F 0.5F 38069F 383 to 581F 1.0F 38070F 563 to 761F 1.0F 380The foregoing set is calibrated for total immersion. With the exception of the first two, each thermometer is provided with anauxiliary scale including 0 C (3
41、2 F), thus providing means for checking at a fixed point, which should be done each time thethermometer is used. The change in ice-point reading should then be applied to all readings. It is only necessary to have aliquid-in-glass thermometer completely calibrated one time. Recalibration is performe
42、d as described in 6.5.86.3.8.5.5.2.2 Partial-Immersion Thermometers General purpose partial-immersion thermometers, as commonly listed in manufac-turers catalogs according to their own specifications, are normally bought and sold without specification of the temperatures ofthe emergent column for th
43、e various temperature indications of the thermometers. In such cases, verification is usually carried outfor the emergent column temperatures prevailing with the verification equipment being employed.5.5.2.3 Special Use Partial-Immersion ThermometersSpecial use partial-immersion thermometers, such a
44、s those covered inSpecification E1, have specified emergent mercury columns or stem temperatures. These thermometers can be used as standardsto calibrate other thermometers similar in all details of construction above the immersion point, but may differ below the immersionpoint to the extent of incl
45、uding an auxiliary ice point scale.5.6 Engraving Date on ASTM ThermometersIf a thermometers specification was changed, the year that it was changed isengraved on the back of the thermometer after the ASTM designation. For example, “12C-98.”6. Procedure6.1 Visual Inspection:6.1.1 Gas Bubbles and Sepa
46、rationsGas bubbles are readily detected and are more likely to occur in shipment than duringservice. No method has been discovered that will entirely prevent such displacement of the gas. If bubbles are observed in the bulb,they can generally be removed by cooling the bulb with dry ice or other conv
47、enient coolant until all the liquid is drawn into theE77 143bulb. Gentle tapping of the thermometer while held upright will cause the bubbles to rise to the surface. It is very important that,if the bulb is cooled in this process below the freezing point of the liquid, care should be exercised to wa
48、rm the stem sufficientlyduring the melting process so that no solidification occurs in the stem; otherwise the bulb may burst or the capillary may splitinternally because of the expansion forces generated in the bulb.6.1.1.1 If a mercury separation is observed in the stem, several different ways are
49、 suggested for joining the columns, dependingon the construction of the thermometer and the type of separation. If a small portion of the liquid has separated at the top of thecolumn and the thermometer is provided with an expansion chamber, the liquid usually can be joined by carefully and slowlyheating the bulb until the separated portion is driven into the expansion chamber. Never heat the bulb in an open flame. When thecolumn itself follows into the chamber, the separated portion usually will join o
