1、Designation: E2251 11E2251 14Standard Specification forLiquid-in-Glass ASTM Thermometers with Low-HazardPrecision Liquids1This standard is issued under the fixed designation E2251; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 The purpose of this standard is to specify liquid-in-glass ASTM thermometers using low hazard thermometric l
3、iquidsdefined in this standard.1.2 This standard specifies liquid-in-glass thermometers graduated in degrees Celsius or degrees Fahrenheit that are frequentlyidentified and used in methods under the jurisdiction of the various technical committees within ASTM. The current approvedthermometers are li
4、sted in Table 1.1.3 The technical requirements for the thermometric liquids used in the thermometers in Table 1 are specified in Annex A1.Tests for conformity to the technical requirements are also found in Annex A1.NOTE 1It has been found by experience that ASTM Thermometers, although developed in
5、general for specific tests, may also be found suitable forother applications, thus precluding the need for new thermometer specifications differing in only minor features. However, it is suggested that technicalcommittees contact E20.05 before choosing a currently designated thermometer for a new me
6、thod to be sure the thermometer will be suitable for theintended application.1.4 For full rationale, see Appendix X1.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriat
7、e safety and health practices and determine the applicability of regulatoryrequirements prior to use.2. Referenced Documents2.1 ASTM Standards:2E1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of ThermometersE344 Terminology Relating to Thermometr
8、y and HydrometryE563 Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature3. Terminology3.1 DefinitionsThe definitions given in Terminology E344 apply.3.2 Definitions of Terms Specific to This Standard:3.2.1 bulb length, nthe distance from the bottom of the bulb to the jun
9、ction of the bulb and the stem tubing.3.2.2 contraction chamber, nan enlargement of the capillary, located below the main scale or between the main scale and theauxiliary scale, that serves to reduce the scale length or to prevent contraction of all the liquid column into the bulb.3.2.3 diameter, nt
10、he largest outside dimension of the glass tubing as measured with a ring gage.3.2.4 expansion chamber, nan enlargement at the top of the capillary to provide protection against breakage caused byexcessive gas pressure.3.2.5 faden thermometer, na thermometer with a long, thin bulb used to determine e
11、mergent stem temperatures.1 This specification is under the jurisdiction of ASTM Committee E20 on Temperature Measurement and is the direct responsibility of Subcommittee E20.05 onLiquid-in-Glass Thermometers and Hydrometers.Current edition approved May 1, 2011May 1, 2014. Published October 2011Sept
12、ember 2014. Originally approved in 2003. Last previous edition approved in 20072011as E225110.11. DOI: 10.1520/E2251-11.10.1520/E2251-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume in
13、formation, 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 technically possible to adequately
14、 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, PO Box C700, West Conshohocken, P
15、A 19428-2959. United States13.2.6 interval error, nthe deviation of the nominal value of a temperature interval from its true value; either for the total range(total interval) or for a part of the range (partial interval).3.2.7 low-hazard liquid, na liquid that is biodegradable, non-hazardous and co
16、nsidered non-toxic in thermometer quantities.NOTE 2It is the responsibility of the manufacturer to determine the suitability of a liquid for this standard. In marking the thermometer with theASTMdesignation the manufacturer is confirming that the liquid in the thermometer is non-hazardous as defined
17、 by current OSHA (Occupational Safety andHealth Administration) standards and non-toxic in thermometer quantities per current definitions of the United States Environmental Protection Agency.3.2.8 thermometric liquid, nthe liquid in a liquid-in-glass thermometer that indicates the value of temperatu
18、re.3.2.9 top of the thermometer, nthe top of the finished instrument.3.2.10 total length, nthe distance from the bottom of the bulb to the top of the finished thermometer, including any specialfinish at the top.overall length of the finished instrument.3.3 Other terms may be found in the Terminology
19、 sections of Specification E1 and Test Method E77.4. Specifications4.1 The individual thermometers shall conform to the detailed specifications given in Table 1, the general requirements specifiedin Sections 5 15, and Annex A1 and Annex A2.NOTE 3Thermometers manufactured to previous revisions of thi
20、s standard shall retain the sameASTM status as those meeting current specifications.NOTE 4The encapsulation (jacketing) of the glass of liquid-in-glass thermometers with polyflourinated hydrocarbons will change their performanceand physical characteristics, including, but not limited to, response ti
21、me, accuracy, and physical dimensions. Therefore, under no circumstances shouldan encapsulated or otherwise modified ASTM thermometer be used in performing tests that specify the use of an ASTM thermometer.5. Type5.1 Each thermometer in Table 1 shall be of the liquid-in-glass type filled with a low
22、hazard thermometric liquid that meets thespecifications in Annex A1. The gas filling above the liquid shall be nitrogen or other suitable inert gas. The filling gas shall bechosen to have very low solubility in the thermometric fluid.6. Stem6.1 StemThe stem shall be made of suitable thermometer tubi
23、ng and shall have a plain front and enamel back.6.2 Top FinishThe top of all thermometers specified in Table 1 shall have a plain rounded finish, except the following, whichshall have the top finish indicated below:below. Any special top finish shall be included in the total length of the thermomete
24、r.6.2.1 Special Finish:6.2.1.1 Any finish suitable for assembly in a standard 304.8-mm (12-in.) non-sparking metal armor with open face; in a cup caseassembly; or in a flushing case assembly as defined in standards the thermometers are used in:Thermometers S58C, S58F, S59C, S59F, S130C, S130F7. Bulb
25、7.1 The bulb shall be made of glass having a viscosity of at least 1014.6 poises at 490C (914F) and at least 1013.4 poises at520C (968F).NOTE 5Thermometers made with bulb glasses having properties close to these minimum requirements should not be subjected to temperatures above405C (760F) or be cont
26、inuously exposed to temperatures above 370C (700F).8. Capillary Clearances8.1 The following distances between graduations and the bulb, and between graduations and enlargements in the capillary, areminimum limits acceptable for thermometers in this standard.NOTE 6In order for a thermometer to be usa
27、ble over its entire graduated range, graduation marks must not be placed too close to any enlargementin the capillary. Insufficient immersion of the thermometric liquid in the main bulb or capillary enlargement, graduation marks placed over parts of thecapillary that have been changed by manufacturi
28、ng operations, or graduations so close to the top of the thermometer that excessive gas pressure resultswhen the thermometric liquid is raised to this level, may lead to appreciable errors.8.1.1 A 13-mm length of unchanged capillary between the bulb and the immersion line or lowest graduation, if th
29、e graduationis not above 100C (212F); a 30-mm length if the graduation is above 100C (212F).8.1.2 A 5-mm length of unchanged capillary between an enlargement and the graduation next below, except at the top of thethermometer.8.1.3 A 10-mm length of unchanged capillary between an enlargement, other t
30、han the bulb, and the immersion line or thegraduation next above, if the graduation is not above 100C (212F); a 30-mm length if the graduation is above 100C (212F).8.1.4 A 10-mm length of unchanged capillary above the highest graduation, if there is an expansion chamber at the top of thethermometer;
31、 a 30-mm length if there is no expansion chamber. For the purposes of this requirement, “an expansion chamber” isinterpreted as an enlargement at the top end of the capillary bore that shall have a capacity equivalent to not less than 20 mm ofunchanged capillary.E2251 1428.2 Due to a change in the m
32、ethods used for scale placement, it is possible to manufacture thermometers that comply with thespecifications given in Table 1, but not meet the requirements for capillary clearances given above. In any case, the distances givenin this section are the governing factor. Under no circumstances shall
33、the scales on thermometers be placed closer than theseminimum distances.9. Graduations and Inscriptions9.1 All graduation lines, figures, and letters shall be clearly defined, suitably colored, and permanent. The width and thesharpness of the graduation lines shall be designed in accordance with nec
34、essary space between the graduations and the desiredaccuracy of interpolation. The middle of the graduation line shall be accurately determinable.9.1.1 A suitably etched thermometer with the etched lines and figures filled with a suitable colorant shall be consideredpermanently marked provided it pa
35、sses the test for permanency of pigment in Test Method Specification E77E1.9.2 Graduation LinesAll graduation lines shall be straight, of uniform width, and perpendicular to the axis of the thermometer.The width of the graduation lines shall be as follows:9.2.1 Group 1Maximum line width 0.10 mm; for
36、 thermometers that may read to fractions of a division, often with magnifyingaids:Thermometers S56C, S56F, S62C, S62F, S63C, S63F, S64C, S64F,S65C, S65F, S66C, S66F, S67C, S67F, S91C, S116C, S117C,S120C9.2.2 Group 2Maximum line width 0.15 mm; for thermometers that may be read to the nearest half div
37、ision or where thecongestion of scale dictates the use of a scale to moderate fineness:Thermometers S5C, S5F, S12C, S12F, S15C, S15F, S18C, S18F,S22C, S22F9.2.3 Group 3Maximum line width 0.20 mm; for thermometers with more open scales, usually read to the nearest division,often times under adverse c
38、onditions where a bold graduation is therefore desired:Thermometers S58C, S58F, S59C, S59F, S130C, S130F9.3 Immersion LineOn partial immersion thermometers an immersion line shall be permanently marked on the front of thethermometer at the distance above the bottom of the bulb as specified in Table
39、1 within a tolerance of 60.5 mm. The immersioninscription shall be written in capital letters and abbreviated (for example, 76 mm immersion shall be written 76 MM IMM.)9.4 Terminal NumbersThe terminal number shall be in full when there are one or more numbered graduations between it andthe next full
40、 number. This rule need not necessarily be followed for:9.4.1 Precision Thermometers:S65F, S66F, S67C, and S67F9.5 Scale Below ZeroWhen a scale extends both above and below 0C or 0F, the two parts of the scale shall be differentiatedby some means. Examples of suitable means are:9.5.1 Different color
41、ants for the graduations for the two parts of the scale,9.5.2 Different style of numerical characters for the two parts of the scale, and9.5.3 Use of minus signs before appropriate numbers below 0C or 0F.10. Special Inscription10.1 The special inscription specified in Table 1 shall be marked on the
42、thermometer in capital letters and Arabic numberswithout the use of periods. Include year of current revision in the ASTM designation (for example ASTM S56C-03).10.1.1 Each thermometer shall be permanently marked with a unique serial number and the manufacturers tradename or mark.10.1.2 Each thermom
43、eter shall have the average coefficient of thermal expansion of the liquid permanently marked.10.1.3 When the length of the thermometer permits, the words “TOTAL IMMERSION” may also be inscribed on the back ofthermometers calibrated for total immersion.11. Permanency of Pigment11.1 The test for perm
44、anency of pigment shall be performed on any convenient portion of the scale section of the thermometer.The pigment shall not chalk, burn out, or loosen as a result of this test (see Test Method Specification E77E1).E2251 14312. Bulb Stability12.1 No test for bulb stability is necessary for any therm
45、ometers currently in this standard. However, should there be in thefuture, the bulb stability test as found in Specification E1 shall be used.13. Scale Error13.1 Thermometers shall be verified and calibrated at the temperatures specified in Table 4. Partial immersion thermometersshall be calibrated
46、for the emergent stem temperatures specified in Table 4 using faden thermometers.13.1.1 At the time of purchase, the scale errors must be within the maximum scale error found in Table 1. The indications ofmany high temperature and fractionally graduated thermometers may change with time and continue
47、d use, due to minute changesin bulb volume. Periodic verification of these thermometers either over the entire scale or reverification at the reference temperature(ice point or steam point), in accordance with procedures set forth in Test Method E77, is recommended.13.2 Due to the application requir
48、ements for range and construction of the following thermometer(s) do not have referencepoints such as ice and steam points:S91C14. Case and Instructions14.1 Each thermometer shall be supplied in a suitable case on which shall appear the following marking (except when atransparent case is used): the
49、letters “ASTM,” the thermometer number (S59C, S59F, etc.), and the temperature range.14.2 Each thermometer shall be supplied with suitable user instructions. See Appendix X2 for Sample User Instructions.15. Methods of Verification and Calibration15.1 Thermometers shall be verified and calibrated at the specified immersion in accordance with Test Method E77. For partialimmersion thermometers careful consideration to emergent stem temperatures shall be observed.E2251 144TABLE 1 Specification for E2251 ASTM ThermometersFIG A. Gener
