1、ANSI/ASHRAE Standard 78-1985 (RA 2017)(Reaffirmation of ANSI/ASHRAE Standard 78-1985)Method of TestingFlow Capacity ofSuction Line Filters andFilter-DriersApproved by ASHRAE on May 31, 2017, and by the American National Standards Institute on June 1, 2017.ASHRAE Standards are scheduled to be updated
2、 on a five-year cycle; the date following the Standard number is the year ofASHRAE approval. The latest edition of an ASHRAE Standard may be purchased on the ASHRAE website (www.ashrae.org)or from ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: ordersashrae.org. Fax:
3、 678-539-2129. Telephone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and Canada). For reprintpermission, go to www.ashrae.org/permissions. 2017 ASHRAE ISSN 1041-2336SPECIAL NOTEThis American National Standard (ANS) is a national voluntary consensus Standard developed unde
4、r the auspices of ASHRAE. Consensus is definedby the American National Standards Institute (ANSI), of which ASHRAE is a member and which has approved this Standard as an ANS, as“substantial agreement reached by directly and materially affected interest categories. This signifies the concurrence of m
5、ore than a simple majority,but not necessarily unanimity. Consensus requires that all views and objections be considered, and that an effort be made toward their resolution.”Compliance with this Standard is voluntary until and unless a legal jurisdiction makes compliance mandatory through legislatio
6、n. ASHRAE obtains consensus through participation of its national and international members, associated societies, and public review.ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. The ProjectCommittee Chair and Vice-Chair must be
7、members of ASHRAE; while other committee members may or may not be ASHRAE members, allmust be technically qualified in the subject area of the Standard. Every effort is made to balance the concerned interests on all Project Committees. The Senior Manager of Standards of ASHRAE should be contacted fo
8、ra. interpretation of the contents of this Standard,b. participation in the next review of the Standard,c. offering constructive criticism for improving the Standard, ord. permission to reprint portions of the Standard.DISCLAIMERASHRAE uses its best efforts to promulgate Standards and Guidelines for
9、 the benefit of the public in light of available information and acceptedindustry practices. However, ASHRAE does not guarantee, certify, or assure the safety or performance of any products, components, or systemstested, installed, or operated in accordance with ASHRAEs Standards or Guidelines or th
10、at any tests conducted under its Standards or Guidelineswill be nonhazardous or free from risk.ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of testing for rating purposes, bysuggesting
11、safe practices in designing and installing equipment, by providing proper definitions of this equipment, and by providing other informationthat may serve to guide the industry. The creation of ASHRAE Standards and Guidelines is determined by the need for them, and conformanceto them is completely vo
12、luntary.In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be made, either stated or implied,that the product has been approved by ASHRAE.ASHRAE Standard Project Committee 78-1985Cognizant TC: 3.3, Refrigerant Contaminant ControlErnest W. Schuma
13、cher, Chair Richard KrauseGordon T. Arnold Walter O. KrauseRichard E. Cawley Larry SpangJohn E. HoffmanASHRAE STANDARDS COMMITTEE 20162017Rita M. Harrold, Chair Michael W. Gallagher Cyrus H. NasseriSteven J. Emmerich, Vice-Chair Walter T. Grondzik David RobinJames D. Aswegan Vinod P. Gupta Peter Sim
14、mondsNiels Bidstrup Susanna S. Hanson Dennis A. StankeDonald M. Brundage Roger L. Hedrick Wayne H. Stoppelmoor, Jr.Drury B. Crawley Rick M. Heiden Jack H. ZarourJohn F. Dunlap, Srinivas Katipamula William F. Walter, BOD ExOJames W. Earley, Jr. Cesar L. Lim Patricia Graef, COKeith I. Emerson Arsen K.
15、 MelikovJulie M. Ferguson R. Lee Millies, Jr.Stephanie C. Reiniche, Senior Manager of StandardsCONTENTSANSI/ASHRAE Standard 78-1985 (RA 2017)Method of Testing Flow Capacity of Suction Line Filters and Filter-DriersSECTION PAGEForeword .21 Purpose.22 Scope23 Definitions .24 Apparatus25 Test Procedure
16、26 Calculation of Results .3Informative Appendix A: Theory of Flow Calculation.4Informative Appendix B: Sample Calculations 5Informative Appendix C: Bibliography .7NOTEApproved addenda, errata, or interpretations for this standard can be downloaded free of charge from the ASHRAEwebsite at www.ashrae
17、.org/technology. 2017 ASHRAE1791 Tullie Circle NE Atlanta, GA 30329 www.ashrae.org All rights reserved.ASHRAE is a registered trademark of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.ANSI is a registered trademark of the American National Standards Institute.2
18、ANSI/ASHRAE Standard 78-1985 (RA 2017)(This foreword is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not been pro-cessed according to the ANSI requirements for a standardand may contain material that has not bee
19、n subject topublic review or a consensus process Unresolved objec-tors on informative material are not offered the right toappeal at ASHRAE or ANSI.FOREWORDASHRAE Standard 78 provides a method for measuring theflow capacity of refrigerant suction line filters and filter-driers.This is a reaffirmatio
20、n of Standard 78-1985 (RA 2007).This standard was prepared under the auspices of ASHRAE.It may be used, in whole or in part, by an association or gov-ernment agency with due credit to ASHRAE. Adherence isstrictly on a voluntary basis and merely in the interest ofobtaining uniform guidelines througho
21、ut the industry. Thisversion of the reaffirmation has no changes.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
22、filters and filter-driersof all 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 pur
23、pose of removing solid con-taminants. The device generally consists of a shell with fit-tings and an internal filtering element.suction line filter-drier: a suction line filter-drier consists of asuction line filter with the addition of desiccant for the pur-pose of removing moisture and other conta
24、minants.filters: for the purpose of this standard, the differencebetween a filter and a filter-drier is not significant. Therefore,both will be referred to as filters hereafter.flow capacity: the refrigerant gas flow that a suction line filterwill pass while maintaining a specified pressure drop acr
25、ossthe clean filter. The flow capacity is expressed in lb/min (g/s)flow at a specified evaporator temperature and return gas tem-perature for the given refrigerant.pressure drop: the difference in pressure between the inletand outlet of the clean filter being tested, including the pres-sure drop in
26、the inlet and outlet fittings, and is expressed inpsi (kPa).specific refrigerant flow rate: the refrigerant flow rate in lb/min (g/s) required to produce one ton (one kW) of refrigera-tion.4. APPARATUS4.1 A flowmeter is used to measure the airflow during thetest. This flowmeter may be of any general
27、ly accepted designthat is suitable for measuring 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 re
28、adability better than 0.1 psi(0.7 kPa) shall be used for measuring pressures and pressuredrop across the filter being tested. 4.3 The temperature at the filter inlet and the flowmeter inletshall be measured with a thermometer or thermocouple. Anaccuracy of 0.5F (0.3C) is adequate.4.4 The installatio
29、n shall be made with line sizes that areconvenient 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 diam
30、eters upstream and 15 diameters downstream of 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 ai
31、r supply system.This tank serves to store an adequate amount of air at a highenough 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 found sat-isfactory. The preferred test
32、setup is illustrated in Figure 1.Clean dry air 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 endof the system. Th
33、e pressure drop across the filter is measuredwith a manometer. 5.2 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, paragraph A5.)Figure 1 Preferre
34、d test setup.ANSI/ASHRAE Standard 78-1985 (RA 2017) 3c. 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
35、the static pressure at the inlet of the filterunder 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 be
36、tween 0.25 psi and 5 psi (1.7 kPaand 34.4 kPa).6. CALCULATION OF RESULTS6.1 Convert the flowmeter readings to lb/min (g/s) of airflowusing the calculations appropriate for the meter involved. Thepressure drop readings should be converted to psi (kPa) if thegage does not read in this unit.6.2 Calcula
37、te the air density in lb/ft3(kg/m3) at the filter inletfor each of the data points. Then calculate the product of thisdensity 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
38、 air density. The resultmust be represented 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 beyon
39、d this point. 6.4 This air curve can be used 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
40、 mass flow rate ofrefrigerant in lb/min (g/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.20 lb/ft3lb/in.22200kg kPam3-4 ANSI/ASHRAE Standard 78-1985 (RA 2017)(This appendix is not part of
41、 this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not been pro-cessed according to the ANSI requirements for a standardand may contain material that has not been subject topublic review or a consensus process. Unresolved objec-
42、tors on informative material are not offered the right toappeal at ASHRAE or ANSIINFORMATIVE APPENDIX ATHEORY OF FLOW CALCULATIONA1. Well-known flow theory states that flow through an ori-fice is described by the following equation:2,3,4where= mass flow rate, lb/min (g/s) K = a constant A = area of
43、the orifice, in.2(m2) = density of the fluid at the inlet condition, lb/ft3(kg/m3) P = pressure drop across the orifice, psi (kPa) A2. Flow through a suction line filter is partly comparable toflow through an orifice and partly comparable to flow througha bed of solids. Item 5 in the bibliography (A
44、ppendix C)states that flow through a bed of solids is governed by the fol-lowing 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/s2A3. It can
45、be shown that for a given cross-sectional area,these two equations are the same. In both cases the mass flowis a function of .A4. Detailed information and experimental verification forthe above relationships using air at various pressures and var-ious refrigerant gases, refrigerant liquids, and wate
46、r havebeen reported in item 4 in the bibliography (Appendix C).These tests show that for a given orifice, curves for all thesevarious fluids are identical up to values of In addition to the above theoretical treatment, other testshave specifically confirmed that this relationship is valid forsuction
47、 line filters.A5. Tests can be performed at inlet air pressure other than 50psig (345 kPa gage) and calculated in a similar manner. Theseresults are also satisfactory. Test results obtained at variousinlet pressures should all fall on the same line.mkA 2P=mPf V22g= P P 20 lb/ft3lb/in.2=2200kg kPam3-
48、Table A1 Test DataTest No.BarometricPressure, psia (kPa Absolute)Filter Inlet Pressure, psig (kPa Gage)Filter Inlet Temperature,F (C)Air Density,lb/ft3(kg/m3)Pressure Drop, psi (kPa) P,lb/ft3 lb/in.2(kg kPa/m3)Airflow,lb/min (g/s)1 14.524 (100.14) 50 (345) 76 (24) 0.325 (5.2) 0.5 (3.4) 0.1625 (17.7)
49、 12.3 (93.0)2 14.524 (100.14) 50 (345) 76 (24) 0.325 (5.2) 1.0 (6.9) 0.3250 (35.9) 17.9 (135.3)3 14.524 (100.14) 50 (345) 76 (24) 0.325 (5.2) 1.5 (10.3) 0.4875 (53.7) 22.0 (166.3)4 14.524 (100.14) 50 (345) 76 (24) 0.325 (5.2) 2.0 (13.8) 0.6500 (71.8) 25.7 (194.3)5 14.524 (100.14) 50 (345) 76 (24) 0.325 (5.2) 5.0 (34.5) 1.6250 (179.4) 40.7 (307.7)ANSI/ASHRAE Standard 78-1985 (RA 2017) 5(This appendix is not part of this standard. It is merelyinformative and does not contain requireme
