1、ASHRAE STANDARDAmerican Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.1791 Tullie Circle NE, Atlanta, GA 30329www.ashrae.orgMethod of TestingFlow Capacity ofSuction Line Filtersand Filter-DriersANSI/ASHRAE Standard 78-1985 (RA 2007)(Reaffirmation of ANSI/ASHRAE Standard 78-198
2、5)Approved by the ASHRAE Standards Committee on June 23, 2007. Approved by the ASHRAE Board of Directors onJune 27, 2007. Approved 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 number i
3、sthe 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 Canada)
4、. Copyright 2007 ASHRAE, Inc.ISSN 1041-2336www.ansi.orgASHRAE STANDARDS COMMITTEE 20062007David E. Knebel, ChairStephen D. Kennedy, Vice-ChairMichael F. BedaDonald L. BrandtSteven T. BushbyPaul W. CabotHugh F. CrowtherSamuel D. Cummings, Jr.Robert G. DoerrRoger L. HedrickJohn F. HoganEli P. Howard,
5、IIIFrank E. JakobJay A. KohlerJames D. LutzCarol E. MarriottMerle F. McBrideMark P. ModeraRoss D. MontgomeryH. Michael NewmanStephen V. SantoroLawrence J. SchoenStephen V. SkalkoBodh R. SubherwalJerry W. White, Jr.James E. WoodsRichard D. Hermans, BOD ExOHugh D. McMillan, III, COClaire B. Ramspeck,
6、Assistant Director of Technology for Standards and Special ProjectsSPECIAL NOTEq=k=p=EkpF=p=eI=o=J=b=EpeobFK=Consensus=k=pf=EkpfFI=peob=kpI=applelogo=K=q=I=K=I=K=Kpeob=I=I=Kpeob=p=m=pK=q=m=sJ=peobX=peob=I=pK=b=mK=q=a=q=p=p=m=peob=WK=pIK=pIK=pI=K=pKDISCLAIMERpeob=p=d=K=eI=peob=I=I=I=I=I=I=peob=p=d=p=
7、d=KASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSpeob=p=d=I=I=I=K=q=peob=p=d=I=Kf=p=d=I=I=I=peobKASHRAE Standard Project Committee 78-1985Cognizant TC: TC 3.3, Refrigerant Contaminant ControlErnest W. Schumacher, ChairGordon T. ArnoldRichard E. CawleyJohn E. HoffmanRichard KrauseWalter O. KrauseL
8、arry SpangCONTENTSANSI/ASHRAE Standard 78-1985 (RA 2007)Method of Testing Flow Capacity of Suction Line Filters and Filter-DriersSECTION PAGEcKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
9、KKKKK ON=mKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK OO=p KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
10、KKKKKKKKKKKKKKKKKKKKKKKKKKK OP=aKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK OQ=KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
11、KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK OR=q=m KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK OS=oKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
12、KKKKKKKKKKKKKKKKKKKKKKKKKKK Pf=W=q=c=KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKPf=_W=p=KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKQf=W=_KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
13、KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKQNOTEWhen addenda, interpretations, or errata to this standard have been approved, 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-Condi
14、tioning Engineers, Inc.1791 Tullie Circle NEAtlanta, GA 30329www.ashrae.orgAll rights reserved.2 ANSI/ASHRAE Standard 78-1985 (RA 2007)(This foreword is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not beenproce
15、ssed according to the ANSI requirements for astandard and may contain material that has not beensubject to public review or a consensus processUnresolved objectors on informative material are notoffered the right to appeal at ASHRAE or ANSI. FOREWORD This is a reaffirmation of ANSI/ASHRAE Standard 7
16、8-1985, which was also reaffirmed in 1990, 1997, and 2003.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 orin part, by an association or government agency with duecredit to ASHRAE. Adhe
17、rence is strictly on a voluntarybasis and merely in the interests of obtaining uniform stan-dards throughout the industry.This standard is intended to provide a method for measur-ing the flow capacity of refrigerant suction line filters and fil-ter-driers. The changes made for the 2007 reaffirmation
18、 wereupdates to the Bibliography.1. PURPOSEThis standard establishes a method for measuring the flowcapacity of refrigerant suction line filters and filter-driers.2. SCOPE2.1 This test method is intended for use on both sealed andreplaceable element type suction line filters and filter-driersof all
19、types.2.2 The test method is based on using air as the testingmedium and calculating the results to refrigerant gas flowunder various application conditions. 3. DEFINITIONSsuction line filter: a device installed in the suction line of arefrigerating system for the purpose of removing solidcontaminan
20、ts. The device generally consists of a shell withfittings and an internal filtering element.suction line filter-drier: a suction line filter-drier consists ofa suction line filter with the addition of desiccant for thepurpose of removing moisture and other contaminants.filters: for the purpose of th
21、is standard, the difference betweena filter and a filter-drier is not significant. Therefore, both willbe referred to as filters hereafter.flow capacity: the refrigerant gas flow that a suction line filterwill pass while maintaining a specified pressure drop acrossthe clean filter. The flow capacity
22、 is expressed in lb/min (g/s)flow at a specified evaporator temperature and return gastemperature for the given refrigerant.pressure drop: the difference in pressure between the inlet andoutlet of the clean filter being tested, including the pressuredrop in the inlet and outlet fittings, and is expr
23、essed in psi(kPa).specific refrigerant flow rate: the refrigerant flow rate in lb/min(g/s) required to produce one ton (one kW) of refrigeration.4. APPARATUS4.1 A flowmeter is used to measure the airflow during thetest. This flowmeter may be of any generally accepted designthat is suitable for measu
24、ring flow with an accuracy of 5%.Acceptable methods of flow measurement are described inANSI/ASHRAE Standard 41.7-1984 (RA 2000), Method ofTest for Measurement of Flow of Gas.4.2 Mercury manometers or other pressure-measuringdevices with an accuracy and readability better than 0.1 psi(0.7 kPa) shall
25、 be used for measuring pressures and pressuredrop across the filter being tested. 4.3 The temperature at the filter inlet and the flowmeterinlet shall be measured with a thermometer or thermocouple.An accuracy of 0.5F (0.3C) is adequate.4.4 The installation shall be made with line sizes that areconv
26、enient for the test being run and that are installed andarranged according to good engineering testing practice. Inpiping the filter being tested, the line shall be the same size asthe filter fittings and shall be straight for a distance of at least15 diameters upstream and 15 diameters downstream o
27、f thetest filter. Pressure taps for the manometer shall be located atleast 2 diameters upstream of the filter and 10 diametersdownstream. The pressure taps shall be 0.062 in. (1.6 mm)diameter burr-free holes. 4.5 A receiver tank is generally part of the air supply sys-tem. This tank serves to store
28、an adequate amount of air at ahigh enough pressure to permit running the test points desiredwithout exhausting the air available at the filter inlet. 5. TEST PROCEDURE5.1 Several different testing procedures have been foundsatisfactory. The preferred test setup is illustrated in Figure 1.Clean dry a
29、ir is supplied to the system. A pressure regulator isused to maintain a constant pressure at the inlet of the filterunder test. Downstream of the filter a control valve adjusts thedesired flow, which is measured on the flowmeter at the end ofthe system. The pressure drop across the filter is measure
30、dwith a manometer. Figure 1 Preferred test setup.ANSI/ASHRAE Standard 78-1985 (RA 2007) 35.2 The test procedure is as follows: a. Install the filter under test. b. Turn on the air supply and adjust the pressure at the inletof the filter to 50 psig 0.5 psig (345 kPa 3 kPa gage).(See Appendix A, parag
31、raph A5.)c. Adjust the airflow with the control valve until the desiredpressure drop is obtained across the filter under test.d. After establishing a steady-state flow, read the pressuredrop across the filter and the flow reading on the flowme-ter. Record the static pressure at the inlet of the filt
32、erunder test and at the flowmeter. Also read the air tempera-ture at these locations. Record the barometric pressure.e. Repeat this procedure to obtain at least four flow ratemeasurements at different test unit pressure drops acrossthe filter under test between 0.25 psi and 5 psi (1.7 kPaand 34.4 kP
33、a).6. CALCULATION OF RESULTS6.1 Convert the flowmeter readings to lb/min (g/s) of air-flow using the calculations appropriate for the meter involved.The pressure drop readings should be converted to psi (kPa) ifthe gage does not read in this unit.6.2 Calculate the air density in lb/ft3(kg/m3) at the
34、 filterinlet for each of the data points. Then calculate the product ofthis density and the pressure drop. 6.3 Prepare a graph on log-log paper (2 3 cycle recom-mended) in which the air mass flow in lb/min (g/s) is plottedvs. the product of pressure drop and air density. The resultmust be represente
35、d by a straight line obtained by leastsquares curve-fitting. Data points that deviate from the line bymore than 10% are suspect and should be checked. The curvemay be extrapolated up to values of the product of density andpressure drop equal to but not beyond this point. 6.4 This air curve can be us
36、ed to calculate refrigerant vaporflow for various conditions. To determine the refrigerant flow,calculate the product of the desired pressure drop and thedesired inlet density condition, and then refer to the curve atthis level to determine the corresponding mass flow rate ofrefrigerant in lb/min (g
37、/s). 6.5 For typical conditions, the information given in Table A1can be used to calculate the refrigerant flow in lb/min (g/s) orin tons (kW) of refrigeration.(This appendix is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the stand
38、ard. 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 notoffered the right to appeal at ASHRAE or ANSIINFORMATIVE APPENDIX ATHEORY OF FL
39、OW CALCULATIONA1. Well-known flow theory states that flow through anorifice is described by the following equation:2,3,4where= mass flow rate, lb/min (g/s) K = a constant A = area of the orifice, in.2(m2) = density of the fluid at the inlet condition, lb/ft3(kg/m3) P = pressure drop across the orifi
40、ce, psi (kPa) A2. Flow through a suction line filter is partly comparableto flow through an orifice and partly comparable to flowthrough a bed of solids. Item 5 in the bibliography(Appendix C) states that flow through a bed of solids isgoverned by the following equation: where V = superficial fluid velocity, ft/min (m/s) f = a function of bed depth, particle diameter, percentvoids, shape factor of particle, and friction factor g = gravitational constant, 32.17 ft/s220 lb/ft3lb/in.22200kg kPam3-mKA 2 P=mPfV22g()=TABLE A1 Test DataTest No.BarometricPressure,psi
