1、Designation: E2251 10Standard 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, the year o
2、f 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-glassASTM thermometers using low hazard thermometric liquidsdef
3、ined in this standard.1.2 This standard specifies liquid-in-glass thermometersgraduated in degrees Celsius or degrees Fahrenheit that arefrequently identified and used in methods under the jurisdictionof the various technical committees within ASTM. The currentapproved thermometers are listed in Tab
4、le 1.1.3 The technical requirements for the thermometric liquidsused in the thermometers in Table 1 are specified in Annex A1.Tests for conformity to the technical requirements are alsofound in Annex A1.NOTE 1It has been found by experience that ASTM Thermometers,although developed in general for sp
5、ecific tests, may also be foundsuitable for other applications, thus precluding the need for new thermom-eter specifications differing in only minor features. However, it issuggested that technical committees contact E20.05 before choosing acurrently designated thermometer for a new method to be sur
6、e thethermometer will be suitable for the intended application.1.4 For full rationale, see Appendix X1.1.5 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 and h
7、ealth practices and determine the applica-bility of regulatory requirements prior to use.2. Referenced Documents2.1 ASTM Standards:2E1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Ther-mometersE344 Terminology Relating to Thermometry and Hydro
8、m-etryE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference Temperature3. Terminology3.1 DefinitionsThe definitions given in TerminologyE344 apply.3.2 Definitions of Terms Specific to This Standard:3.2.1 bulb length, nthe distance from the bottom of thebulb to the junction of the
9、bulb and the stem tubing.3.2.2 contraction chamber, nan enlargement of the cap-illary, located below the main scale or between the main scaleand the auxiliary scale, that serves to reduce the scale length orto prevent contraction of all the liquid column into the bulb.3.2.3 diameter, nthe largest ou
10、tside dimension of theglass tubing as measured with a ring gage.3.2.4 expansion chamber, nan enlargement at the top ofthe 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 emergent stem tem
11、peratures.3.2.6 interval error, nthe deviation of the nominal valueof a temperature interval from its true value; either for the totalrange (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 considered non-toxic i
12、n thermometer quan-tities.NOTE 2It is the responsibility of the manufacturer to determine thesuitability of a liquid for this standard. In marking the thermometer withtheASTM designation the manufacturer is confirming that the liquid in thethermometer is non-hazardous as defined by current OSHA (Occ
13、upationalSafety and Health Administration) standards and non-toxic in thermom-eter quantities per current definitions of the United States EnvironmentalProtection Agency.3.2.8 thermometric liquid, nthe liquid in a liquid-in-glassthermometer that indicates the value of temperature.3.2.9 top of the th
14、ermometer, nthe top of the finishedinstrument.3.2.10 total length, nthe distance from the bottom of thebulb to the top of the finished thermometer, including anyspecial finish at the top.1This specification is under the jurisdiction of ASTM Committee E20 onTemperature Measurement and is the direct r
15、esponsibility of Subcommittee E20.05on Liquid-in-Glass Thermometers and Hydrometers.Current edition approved Nov. 1, 2010. Published December 2010. Originallyapproved in 2003. Last previous edition approved in 2007 as E225107. DOI:10.1520/E2251-10.2For referenced ASTM standards, visit the ASTM websi
16、te, 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United State
17、s.3.3 Other terms may be found in the Terminology sectionsof Specification E1 and Test Method E77.4. Specifications4.1 The individual thermometers shall conform to the de-tailed specifications given in Table 1, the general requirementsspecified in Sections 5-15, and Annex A1 and Annex A2.NOTE 3Therm
18、ometers manufactured to previous revisions of thisstandard shall retain the same ASTM status as those meeting currentspecifications.NOTE 4The encapsulation (jacketing) of the glass of liquid-in-glassthermometers with polyflourinated hydrocarbons will change their perfor-mance and physical characteri
19、stics, including, but not limited to, responsetime, accuracy, and physical dimensions. Therefore, under no circum-stances should an encapsulated or otherwise modifiedASTM thermometerbe used in performing tests that specify the use of an ASTM thermometer.5. Type5.1 Each thermometer in Table 1 shall b
20、e of the liquid-in-glass type filled with a low hazard thermometric liquid thatmeets the specifications in Annex A1. The gas filling above theliquid shall be nitrogen or other suitable inert gas. The fillinggas shall be chosen to have very low solubility in thethermometric fluid.6. Stem6.1 StemThe s
21、tem shall be made of suitable thermometertubing and shall have a plain front and enamel back.6.2 Top FinishThe top of all thermometers specified inTable 1 shall have a plain rounded finish, except the following,which shall have the top finish indicated below:6.2.1 Special Finish:6.2.1.1 Any finish s
22、uitable for assembly in a standard304.8-mm (12-in.) non-sparking metal armor with open face;in a cup case assembly; or in a flushing case assembly asdefined in standards the thermometers are used in:Thermometers S59C, S59F7. Bulb7.1 The bulb shall be made of glass having a viscosity of atleast 1014.
23、6poises at 490C (914F) and at least 1013.4poises at520C (968F).NOTE 5Thermometers made with bulb glasses having propertiesclose to these minimum requirements should not be subjected to tempera-tures above 405C (760F) or be continuously exposed to temperaturesabove 370C (700F).8. Capillary Clearances
24、8.1 The following distances between graduations and thebulb, and between graduations and enlargements in the capil-lary, are minimum limits acceptable for thermometers in thisstandard.NOTE 6In order for a thermometer to be usable over its entiregraduated range, graduation marks must not be placed to
25、o close to anyenlargement in the capillary. Insufficient immersion of the thermometricliquid in the main bulb or capillary enlargement, graduation marks placedover parts of the capillary that have been changed by manufacturingoperations, or graduations so close to the top of the thermometer thatexce
26、ssive gas pressure results when the thermometric liquid is raised tothis level, may lead to appreciable errors.8.1.1 A 13-mm length of unchanged capillary between thebulb and the immersion line or lowest graduation, if thegraduation is not above 100C (212F); a 30-mm length if thegraduation is above
27、100C (212F).8.1.2 A 5-mm length of unchanged capillary between anenlargement and the graduation next below, except at the top ofthe thermometer.8.1.3 A 10-mm length of unchanged capillary between anenlargement, other than the bulb, and the immersion line or thegraduation next above, if the graduatio
28、n 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 thehighest graduation, if there is an expansion chamber at the topof the thermometer; a 30-mm length if there is no expansionchamber. For the purposes of this requirement
29、, “an expansionchamber” is interpreted as an enlargement at the top end of thecapillary bore that shall have a capacity equivalent to not lessthan 20 mm of unchanged capillary.8.2 Due to a change in the methods used for scale place-ment, it is possible to manufacture thermometers that complywith the
30、 specifications given in Table 1, but not meet therequirements for capillary clearances given above. In any case,the distances given in this section are the governing factor.Under no circumstances shall the scales on thermometers beplaced closer than these minimum distances.9. Graduations and Inscri
31、ptions9.1 All graduation lines, figures, and letters shall be clearlydefined, suitably colored, and permanent. The width and thesharpness of the graduation lines shall be designed in accor-dance with necessary space between the graduations and thedesired accuracy of interpolation. The middle of the
32、graduationline shall be accurately determinable.9.1.1 A suitably etched thermometer with the etched linesand figures filled with a suitable colorant shall be consideredpermanently marked provided it passes the test for permanencyof pigment in Test Method E77.9.2 Graduation LinesAll graduation lines
33、shall bestraight, of uniform width, and perpendicular to the axis of thethermometer. The width of the graduation lines shall be asfollows:9.2.1 Group 1Maximum line width 0.10 mm; for ther-mometers that may read to fractions of a division, often withmagnifying aids:Thermometers S56C, S56F, S62C, S62F
34、, S63C, S63F, S64C, S64F,S65C, S65F, S66C, S66F, S67C, S67F, S91C, S116C, S117C,S120C9.2.2 Group 2Maximum line width 0.15 mm; for ther-mometers that may be read to the nearest half division or wherethe congestion of scale dictates the use of a scale to moderatefineness:Thermometers S12C, S12F9.2.3 G
35、roup 3Maximum line width 0.20 mm; for ther-mometers with more open scales, usually read to the nearestdivision, often times under adverse conditions where a boldgraduation is therefore desired:Thermometers S58C, S58F, S59C, S59F, S130C, S130FE2251 1029.3 Immersion LineOn partial immersion thermomete
36、rsan immersion line shall be permanently marked on the front ofthe thermometer at the distance above the bottom of the bulb asspecified in Table 1 within a tolerance of 60.5 mm. Theimmersion inscription shall be written in capital letters andabbreviated (for example, 76 mm immersion shall be written
37、76 MM IMM.)9.4 Terminal NumbersThe terminal number shall be infull when there are one or more numbered graduations betweenit and the next full number. This rule need not necessarily befollowed for:9.4.1 Precision Thermometers:S65F, S66F, S67C, and S67F9.5 Scale Below ZeroWhen a scale extends both ab
38、oveand below 0C or 0F, the two parts of the scale shall bedifferentiated by some means. Examples of suitable means are:9.5.1 Different colorants for the graduations for the twoparts of the scale,9.5.2 Different style of numerical characters for the twoparts of the scale, and9.5.3 Use of minus signs
39、before appropriate numbers below0C or 0F.10. Special Inscription10.1 The special inscription specified in Table 1 shall bemarked on the thermometer in capital letters and Arabicnumbers without the use of periods. Include year of currentrevision in the ASTM designation (for example ASTM S56C-03).10.1
40、.1 Each thermometer shall be permanently marked witha unique serial number and the manufacturers tradename ormark.10.1.2 Each thermometer shall have the average coefficientof thermal expansion of the liquid permanently marked.10.1.3 When the length of the thermometer permits, thewords “TOTAL IMMERSI
41、ON” may also be inscribed on theback of thermometers calibrated for total immersion.11. Permanency of Pigment11.1 The test for permanency of pigment shall be performedon any convenient portion of the scale section of the thermom-eter. The pigment shall not chalk, burn out, or loosen as a resultof th
42、is test (see Test Method E77).12. Bulb Stability12.1 No test for bulb stability is necessary for any thermom-eters currently in this standard. However, should there be in thefuture, the bulb stability test as found in Specification E1 shallbe used.13. Scale Error13.1 Thermometers shall be verified a
43、nd calibrated at thetemperatures specified in Table 4. Partial immersion thermom-eters shall be calibrated for the emergent stem temperaturesspecified in Table 4 using faden thermometers.13.1.1 At the time of purchase, the scale errors must bewithin the maximum scale error found in Table 1. Theindic
44、ations of many high temperature and fractionally gradu-ated thermometers may change with time and continued use,due to minute changes in bulb volume. Periodic verification ofthese thermometers either over the entire scale or reverificationat the reference temperature (ice point or steam point), inac
45、cordance with procedures set forth in Test Method E77,isrecommended.13.2 Due to the application requirements for range andconstruction of the following thermometer(s) do not havereference points such as ice and steam points:S91C14. Case and Instructions14.1 Each thermometer shall be supplied in a su
46、itable caseon which shall appear the following marking (except when atransparent case is used): the letters “ASTM,” the thermometernumber (S59C, S59F, etc.), and the temperature range.14.2 Each thermometer shall be supplied with suitable userinstructions. See Appendix X2 for Sample User Instructions
47、.15. Methods of Verification and Calibration15.1 Thermometers shall be verified and calibrated at thespecified immersion in accordance with Test Method E77. Forpartial immersion thermometers careful consideration to emer-gent stem temperatures shall be observed.E2251 103TABLE 1 Specification for E22
48、51 ASTM ThermometersFIG A. General Reference Figure for Table 1(Specific figures associated with individual thermometers are found at the end of Table 4)Explanatory Notes for Table 1 (numbers correspond to those found in Table 1 of Specification E1 whenever possible):AAn expansion chamber is provide
49、d for relief of gas pressure to avoid distortion of the bulb at higher temperatures. It is not for the purpose of joiningthermometric liquid separations and under no circumstances should the thermometer be heated above the highest temperature reading.MFor kinematic viscosity thermometers, the ice-point reading shall be taken within1hafterbeingatthetesttemperature for not less than 3 min. The ice-pointreading shall be expressed to the nearest 0.01C or 0.02F and applied as explained in Test Method E77, Section 13.OCapillary clearances
