1、ASHRAE STANDARDAmerican Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.1791 Tullie Circle NE, Atlanta, GA 30329www.ashrae.orgSealed Glass TubeMethod to Test theChemical Stability ofMaterials for Use withinRefrigerant SystemsANSI/ASHRAE Standard 97-2007(Supersedes ANSI/ASHRAE St
2、andard 97-1999 RA 2003)Approved by the ASHRAE Standards Committee on June 23, 2007, by the ASHRAE Board of Directors on June 27,2007, and by the American National Standards Institute on June 28, 2007.ASHRAE Standards are scheduled to be updated on a five-year cycle; the date following the standard n
3、umber isthe year of ASHRAE Board of Directors approval. The latest copies may be purchased from ASHRAE CustomerService, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: ordersashrae.org. Fax: 404-321-5478. Tele-phone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and
4、Canada). Copyright 2007 ASHRAE, Inc.ISSN 1041-2336www.ansi.orgSPECIAL NOTEq=k=p=EkpF=p=eI=o=J=b=EpeobFK=k=pf=EkpfFI=peob=kpI=applelogo=K=q=I=K=I=K=Kpeob=I=I=Kpeob=p=m=pK=qm=sJ=peobX=peobI=pK=b=m=K=q=j=p=peob=WK=pIK=pIK=pI=K=pKASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSpeob=p=d=I=I=I=K=q=peob=p
5、=d=I=Kf=p=d=I=I=I=peobKDISCLAIMERpeob=p=d=K=eI=peob=I=I=I=I=I=I=peob=p=d=p=d=KASHRAE Standard Project Committee 97-1999Cognizant TC: TC 3.2, Refrigerant System ChemistrySPLS Liaison: Thomas E. Watsono=dK=a*I=Chairg=cI=Secretaryt=oK=Gi=iK=iGq=oK=oGp=oG=pGe=_q=i=to=tK=v*Denotes members of voting statu
6、s when the document was previously approved for publicationASHRAE STANDARDS COMMITTEE 20062007a=bK=hI=Chairp=aK=hI=Vice-Chairj=cK=_a=iK=_p=qK=_m=tK=e=cK=p=aK=I=gKo=dK=ao=iK=eg=cK=eb=mK=eI=fffc=bK=gg=K=hg=aK=i=bK=jj=cK=j_j=mK=jo=aK=jeK=j=kp=sK=pi=gK=pp=sK=p_=oK=pg=tK=tI=gKg=bK=to=aK=eI=BOD ExOe=aK=jj
7、I=fffI=COClaire B. Ramspeck, Assistant Director of Technology for Standards and Special ProjectsSTANDARDS REAFFIRMATION SUBCOMMITTEE 20062007*g=iI=Chairj=_p=_oK=j=j_=pg=t*For the 2007 revision in which minor changes were performed(i.e., updating references), SRS acted as the consensus project commit
8、teeCONTENTSANSI/ASHRAE 97-2007Sealed Glass Tube Method to Test the Chemical Stability of Materials for Use within Refrigerant SystemsSECTION PAGEForeword1 Purpose 22 Scope 23 Apparatus . 24 Procedure for Preparing the Sealed Glass Tubes 35 Aging the Sealed Glass Tubes . 66 Analysis of the Tubes . 67
9、 Significance of Results . 78 Safety Requirements 79 References . 8Informative Appendix A: Calculation of Refrigerant Pressure in Sealed Tubes Containing 0.7 mL of Refrigerant . 8Informative Appendix B: Bibliography. 10NOTEWhen addenda, interpretations, or errata to this standard have been approved,
10、 they can be downloadedfree of charge from the ASHRAE Web site at http:/www.ashrae.org. Copyright 2007 American Society of Heating,Refrigerating and Air-Conditioning Engineers, Inc.NTVN=q=kbI=d=PMPOVKK=K2 ANSI/ASHRAE Standard 97-2007(This foreword is not part of this standard. It is merelyinformativ
11、e and does not contain requirements necessaryfor conformance to the standard. It has not beenprocessed according to the ANSI requirements for astandard and may contain material that has not beensubject to public review or a consensus process.Unresolved objectors on informative material are notoffere
12、d the right to appeal at ASHRAE or ANSI.)FOREWORDThis is a revision of ASHRAE Standard 97-1999(RA 2003).This standard describes a uniform means for testing thevarious materials used within hermetic and nonhermeticrefrigerant systems. It is primarily intended as an acceleratedscreening tool and can p
13、rovide valuable information on thechemical stability of system materials.This standard was prepared under the auspices of theAmerican Society of Heating, Refrigerating and Air-Condi-tioning Engineers (ASHRAE). It may be used, in whole or inpart, by an association or government agency with due credit
14、to ASHRAE. Adherence is strictly on a voluntary basis andmerely in the interests of obtaining uniform standardsthroughout the industry.The changes made for the 2007 revision were: references were updatedreferences were numbered in the order they are cited inthe body of the textinformative bibliograp
15、hy was added as Appendix B1. PURPOSEThe purpose of this standard is to establish a test proce-dure utilizing sealed glass tubes for the evaluation of materialsfor use in refrigerant systems.2. SCOPE2.1 This standard describes the preparation of sealedglass tubes and the procedure for charging them w
16、ithrefrigerant, lubricant, other materials to be tested, or com-binations of these.2.2 A procedure for aging the tubes, usually at elevated tem-peratures, is described. The tubes are evaluated by quantita-tive or qualitative analysis, or both, of the tube contents toyield information for determining
17、 the compatibility or chem-ical stability of materials in refrigerant systems.2.3 The technique described may be used for evaluatingmany different types of materials. Therefore, the standarddoes not describe in detail the preparation of the materials tobe tested prior to placing them in the glass tu
18、bes, the condi-tions of exposure, nor the methods of analysis.2.4 Detailed safety precautions are included in Section 8,“Safety Requirements.”3. APPARATUS3.1 A sealed glass tube generally consists of a borosilicateglass tube 9 mm (0.35 in.) OD 7 mm (0.27 in.) ID approx-imately 180 mm (7.1 in.) long
19、with one end formed into around bottom. The above are the finished dimensions. Thetube is charged with the refrigerant and materials to be testedand then sealed in a rounded tip at the other end.3.2 The tube charging apparatus is illustrated in Figure 1.This apparatus consists of a manifold (metal o
20、r glass), vac-uum pump, pressure gauge, high vacuum gauge, refrigerantcylinder, valves, and filling ports. The function of this appa-ratus is to evacuate the tube, add refrigerant, and seal italong with the test materials. It is calibrated so that therefrigerant may be added very accurately by follo
21、wing thechange in pressure on the vacuum gauge as refrigerant isadded to the tube.3.3 An aluminum block is used for aging the sealed glasstubes at elevated temperatures. The aluminum block hascylindrical holes in it to support the sealed glass tubes beingtested. The purpose of the aluminum block is
22、to protect thetubes from each other in the event of breakage. A further func-tion is to maintain temperature uniformity. A typical alumi-num block is illustrated in Figure 2. The holes in the blockshould be drilled completely through, and the block shouldhave a separate removable bottom to simplify
23、cleaning. Avent may be included to release pressure should a tube burst.The overall dimensions shall be sized to accommodate thedesired number of sealed glass tubes while maintaining ade-quate wall thickness. A small wad of glass wool should beplaced in the bottom of the drilled hole to cushion and
24、supportthe tubes during aging.3.4 Individual pipe chambers may be more convenient fortesting a small number of samples, instead of the aluminumblock described above. These individual chambers may beconstructed of metal pipe and closed at both ends withthreaded caps.Figure 1 Manifold for filling glas
25、s tubes.ANSI/ASHRAE Standard 97-2007 33.5 The electrically heated aging oven shall have mechani-cal convection capable of maintaining a uniform temperaturewith 1.0C (1.8F) throughout the test chamber. The ovenchamber shall be large enough to accommodate the aluminumblock and allow for adequate air c
26、irculation and venting. Theoven shall be equipped with an indicating controller with acontrol sensitivity of 0.5C (0.9F).3.6 The tube opening apparatus is illustrated in Figure 3.This apparatus is suitable for safely and conveniently openinga sealed tube for subsequent analysis of the contents. An a
27、lter-native apparatus is illustrated in Figure 4.3.7 Flexible tubing (PVC or rubber) is often used in prepa-ration of sealed glass tubes. It is important to clean the tubingprior to use. It must be free of excess plasticizer, lubricants,powders, and other contaminants.4. PROCEDURE FOR PREPARING THE
28、SEALED GLASS TUBES4.1 Preparation of the Glass Tube4.1.1 The preparation of these tubes shall be performed bysomeone skilled in the art of glass blowing. A skilled glassblower will take into consideration such factors as a. proper storage of the glass tubing,b. proper cleanliness of the tubing,c. cu
29、tting to obtain square ends,d. the use of a small, sharply pointed oxygen-gas flame andproper glass blowers torch,e. obtaining a uniform wall thickness throughout, andf. proper safety precautions (see Section 8).4.1.2 Typically the tubes are made from 9 mm (0.35 in.)OD standard wall borosilicate gla
30、ss tubing. This tubing has anID approximately 7 mm (0.27 in.), and the tube should be cutinto 240 mm (9.45 in.) lengths. One end is sealed to form arounded bottom. The other end is fire polished.Figure 2 Aluminum block for aging sealed tubes.Figure 4 Alternative tube opening apparatus.Figure 3 Tube
31、opening apparatus.4 ANSI/ASHRAE Standard 97-2007desiccator at room temperature. Break the vacuum with drynitrogen and store in the desiccator until use.4.2.4 Materials, such as motor insulation, wire enamel,elastomers, plastics, lubricants, or materials of construction,may be added to the sealed gla
32、ss tube for evaluation. Thesematerials should be carefully prepared so that they are free ofcontaminants and are representative of the refrigerating sys-tem. Failure to properly prepare test materials may result inerroneous and misleading conclusions.4.2.5 Sufficient tubes with identical contents sh
33、ould beprepared such that one can be stored unaged for later ref-erence and the others can be used in the necessary testsafter aging.4.3 Adding Materials to Tubes4.3.1 Insertion. The order of insertion of materials in thetubes varies, depending on the physical size, shape, and com-position (gas, liq
34、uid, or solid) of the material to be tested.Generally, solid materials are placed in the tube first, followedby the lubricant and nonvolatile liquids and then refrigerantsand other gases. 4.3.2 Adding Solid Materials. Do not handle the cleansample or metals with bare or gloved handsuse clean for-cep
35、s. Purge the tube with a gentle flow of dry nitrogen, thencover it with a stopper or plastic cap, and store in a suitabledesiccator.4.3.3 Adding Liquid Materials. Load a 5 mL syringewith lubricant to be used in the test, and, using a syringe witha locking needle, attach a 150 mm (5.9 in.) long #18 n
36、eedle.Insert a 2 mm (0.08 in.) diameter 140 mm (5.5 in.) longglass tube into the tube to be loaded. The tube should have ahandle or clamp at one end to prevent its falling into thelarger glass tube. Insert the #18 needle through the 2 mm(0.08 in.) glass tube. The syringe needle should extendthrough
37、the entire length of the 2 mm (0.08 in.) glass tube.Inject 0.7 mL of lubricant, withdraw the syringe, and thenwithdraw the 2 mm (0.08 in.) glass tube. The glass tube pre-vents the last drop of lubricant on the syringe from contactingthe upper surface of the glass tube. Purge the tube with a gen-tle
38、flow of dry nitrogen, replace stopper or cap, and store in adesiccator.4.3.4 Forming Capillary in Tube. Remove the sampletubes from the desiccator, remove the stopper or cap, andplace a 30 mm (1.2 in.) length of rubber or PVC tubing overthe open end of the tube so about 15 mm (0.6 in.) of sampletube
39、 is covered. About 60 mm (2.4 in.) from the unsealed end,reduce the tube to a capillary size large enough to pass a #18needle. This operation must be done by an individual ade-quately skilled in glass blowing. Other connection means maybe used, such as commercially available ferrule fittings orcompr
40、ession O-ring seals.4.3.5 Preparing Manifold for Use. Prepare the refriger-ant tube loading apparatus for use (Figure 1). The interior ofthis apparatus shall be clean, dry, and thoroughly leak-tested.4.1.3 The tubes must be scrupulously clean. The tubingshould be stored in a sealed container so that it does not col-lect any cont
