阀门标准-MSS SP120 1997(天选打工人).pdf

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1、SP-120 STANDARD PRACTICE FLEXIBLE GRAPHITE PACKING SYSTEM FOR RISING STEM STEEL VALVES(DESIGN REQUIREMENTS)Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry,Inc.127 Park Street,N.E.Vienna,Virginia 221 80(703)28 1-66 13 Approved March 1997 COPYRIGH

2、T Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling Services STD-MSS SP-120-ENGL 1977 5770biO 0500722 877 MSS STANDARD PRACTICE SP-120 An MS

3、S Standard Practice is intended as a basis for common practice by the manufacturer,the user,and the general public.The existence of an MSS Standard Practice does not in itself preclude the manufacture,sale,or use of products not conforming to the Standard Practice.Mandatory conformance is establishe

4、d only by reference in a code,specification,sales contract,or public law,as applicable.U.S.customary units in this SP are the standard;metric units are for reference only.Unless otherwise specifically noted in this MSS SP,any standardreferred to herein is identified by the date of issue that was app

5、licable to the referenced standard(s)at the date of issue of this MSS SP.(See Annex A.)Any part of this standard may be quoted.Credit lines should read Extracted from MSS SP-120-1997,with permission of the publisher,the Manufacturers Standardization Society.Reproduction prohibited under copyright co

6、nvention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry,Inc.Copyright,1997 by Manufacturers Standardization Society of the Valve and Fittings Industry,Inc.Printed in U.S.A.i Previous page is blank COPYRIGHT Manufacturers Standardi

7、zation Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling Services-STD-MSS SP-LZCI-ENGL 1777 H 5770biO 0500723 723 MSS STANDARD PRACTICE SP-120 FOREWORD This Standard Prac

8、tice(SP)was developed by a cooperative effort of representatives of Valve and Packing Manufacturers.This SP is intended primarily to be an aid for the manufacture and procurement of standardized packing system design features for rising stem steel valves that utilize flexible graphite packing.Howeve

9、r,this does not preclude the use of these system features for other types of packing systems since this SP represents the consensus input from a broad spectrum of industry applications.This SP shall not be construed to be effective for all pressures and types of services expected of ASME B16.34 valv

10、es.Special service applications such as low fugkive emissions control or toxic fluid may require additional or different design measures that are outside the scope of this standard practice.11 COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling S

11、ervicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling Services-STD*MSS SP-120-ENGL 1777 5770b40 0500724 bbT D MSS STANDARD PRACTICE SP-120 1 d Section TABLE OF CONTENTS Page FOREWORD.ii 1.SCOPE.1 2.DEFINITIONS.1 3.PACKING ASSEMBLY.1 4.STEM.2

12、 5.PACKING GLAND.2 6.PACKINGCHAMBER.2 7.PACKING WASHER OR VALVE BONNET.2 TABLE 1.PACKING SYSTEM DETAILS(U.S.UNITS).3 4 1M.PACKING SYSTEM DETAILS(METRIC UNITS).FIGURE 1.STEM/BONNET DETAILS(U.S.UNITS).5 6 2.GEOMETRIC SYMBOL DEFINITIONS.7 IM.STEM/BONNET DETAILS(METRIC UNITS).ANNEX A:REFERENCED STANDARD

13、S.8.1ll COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD-MSS SP-LZO-ENGL II797 W 5770biO 0500725 5Tb H STANDARD PRACT

14、ICE SP-120 MSS FLEXIBLE GRAPHITE PACKING SYSTEM FOR RISING STEM STEEL VALVES(DESIGN REQUIREMENTS)1.SCOPE(a)and end rings.Flexible graphite packing assem-bly that is constructed with a braided carbon or graphite or metal mesh that reinforces the flexible graphite may not require end rings.The end rin

15、gs shall serve as wipers and antiextrusion devices to keep the flexible graphite in the packing chamber during operation,including stroking,of the valve.Individual center rings 1.1 This Standard Practice provides packing material and dimensional requirements for valve packing,packing chamber,packing

16、 gland,pack-ing washer,bonnet,and stem as they relate to the total packing assembly.1.2 This Standard Practice applies to standard,special,and limited Class 150 through Class 4500(including intermediate classes)ASME B16.34 type steel gate,globe,and angle valves designed with rotating/rising,and non-

17、rotating/rising stems.1.3 This Standard Practice applies to valves in which a flexible graphite packing assembly is used as the primary stem sealing system.1.4 This Standard Practice does not apply to valves that include a lantern ring as part of its packing system nor to bonnetless valves with spli

18、t glands.may contain up to 2 splits per ring to facilitate valve packing installation.Braided end rings shall contain a maximum of 1 split per ring and molded end rings shall contain a maximum of 2 splits per ring.The end ring properties shall be designed to deter the extrusion and/or ero-sion of th

19、e center flexible graphite rings during valve operation.Packing assemblies of flexible graphite without end rings may be used;however,the diametrical clearance specified in Table 1 shall be reduced to a maximum of 50%of that required for higher than Class 300 valves.The packing shall also be qualifi

20、ed to the requirements of MSS SP-121,Qualification Testing Methods for Stem Packing for Rising Stem Steel Valves.2.DEFINITIONS See MSS SP-96 for definitions of terms used in this Standard Practice.3.2 The packing assembly shall contain a dis-persed passive corrosion inhibitor,dispersed embedded acti

21、ve corrosion inhibitor or a suitable combination of inhibitors-to minimize stem See Figure 2 for definitions of symbols used in this Standard Practice.pitting caused by the galvanic corrosion pheno-menon set up in a wet valve packing chamber.Inhibitors in end rings are optional unless other-wise spe

22、cified by the purchaser.3.PACKING ASSEMBLY 3.1 The packing shall be composed of center and end rings or a cylinder of flexible graphite NOTE:(a)This standard is not intended to apply to valves developed for and predominantly used in instrument piping systems.(See MSS SP-99,Instrument Valves,and MSS

23、SP-105,Instrument Valves for Code Applications.)3.3 The pre-installed density and dimensions of the flexible graphite packing shall be at the valve manufacturers option.The final adjusted density and dimensions of the packing assembly shall be capable of sealing with no visible leakage when the valv

24、e is tested at a pressure equal to the valves 100F pressure rating at ambient conditions.The as-shipped remaining packing and packing gland adjustment(packing gland tight)shall be greater than 10%of the minimum depth of the packing chamber listed in Table 1.1 Previous page is blank COPYRIGHT Manufac

25、turers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD-MSS SP-120-ENGL 1997 5770b40 050092b Li32 MSS STANDARD PRACTICE SP-120 3.4 The dimens

26、ional requirements of the pack-ing assembly shall be per Table 1.The minimum width“W”and minimum depth“L”are listed.3.5 Smaller packing widths(“W”)and/or smaller depths(“L”)may be used when qualified to the requirements of MSS SP-121,Qualifica-_ tion Testiiig Methods for Stem Packing for Rising Stem

27、 Steel Valves.All other provisions of this Standard Practice shall apply.STEM 4.-4.1 The maximum total stem dimensional toler-ances(bilateral or unilateral)shall be per Table 1.The stem finish shall be 32 Ra(microinch)(0.80 micrometers)or smoother.These stem charac-teristics shall apply in the area

28、that contacts the packing during the full stroking of the valve.The maximum stem O.D.tolerance as shown in Table 1 applies to the stem diameter that contacts the packing I.D.4.2 The stem O.D.dimensional tolerance shall be such that the maximum diametrical clearance between the packing gland or follo

29、wer I.D.(“B”)and bonnet or packing washer(“C”)as required in Table 1 is not exceeded.4.3 The stem O.D.that contacts the packing during the full stroking of the valve shall meet circularity,taper,and straightness requirements encompassed in a cylindricity tolerance of 0.003”(0.08mm)for 3”and smaller

30、stems and 0.004”(O.1Omm)for stems larger than 3”.(See Figure 1.)4.4 The stem surface that contacts the packing during full stroking of the valve shall be free of scratches,pits,or voids deeper than 0.002“(0.05mm).5.PACKING GLAND The dimensional tolerances of the gland or follower I.D.and O.D.shaii b

31、e such that the maximum diametrical clearance between the stem and gland or follower(“B”)and packing chamber bore and gland or follower(“A”)illustrated in Table 1 are not exceeded.6.PACKING CHAMBER 6.1 The dimensional tolerance of the packing chamber shall be such that the maximum dia-metrical clear

32、ance between gland or follower and the packing chamber(“A?illustrated in Table 1 is not exceeded.The packing depth 4W or 5W illustrated in Table 1 refers to the equivalent of 4 or 5 square rings of packing which includes the top and bottom end rings.The packing chamber surface finish shall be 125 Ra

33、(microinch)(3.2 micrometers)or smoother,as illustrated in Table 1.A chamfer or radius may be used at the entrance of the packing chamber.6.2 The packing chamber bore shall meet squareness to the bonnet gasket surface,or other appropriate datum surface encompassed in a perpendicularity tolerance of 0

34、.006”(O.15mm)regardless of bore size.(See Figure 1.)6.3 The packing chamber bore shall meet circularity,taper and straightness requirements encompassed in a cylindricity tolerance of 0.006”(O.15mm).(See Figure 1.)6.4 The packing chamber bore and bonnet stem hole shall be concentric within a position

35、al tolerance 3 of 0.005(O.13mm)as presented in Figure 1.6.5 The packing chamber bore shall be free of scratches,pits,or voids deeper than 0.006”(0.015mm).7.PACKING WASHER OR VALVE BONNET The tolerance on the valve bonnet or the packing washer,when a packing washer is used,shall be such that the maxi

36、mum diametrical clearance between the stem and the bonnet or packing washer(“C?,illustrated in Table 1,is not exceeded.2 COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and

37、FittingsLicensed by Information Handling ServicesSTD-MSS SP-120-ENGL 1777 5770b40 0500727 377=MSS STANDARD PRACTICE SP-120 STEM SIZE TABLE I-PACKING SYSTEM DETAILS(U.S.UNITS)STEM PkXItG CHAYBER 1.D TOL.#I-MAXIMUM T a.#2-Iw DIAMETRICAL IAMETRICAL PACKING WASHER I 7 DARNL(SEE 4.2 WHEN PACKING WASHER I

38、S USED)(WHEN USED)11/16 thru I l/4 NOTE:DIMENSIONS I N INCHES 0.010 I O.008 l/4 thru 1/2 I 0.008 1 0.010 1/2 thru 11/16 I 0.008 I 0.010 I 114 thru 2 I 0.009 1 0.010 2 thru 3 O.009 0.010 3 thru 3 l/2 0.01 I 0.015 3 1/2 thru 4 l/4 0.01 I 1 0.015 4 114 thru 5 I 0.011 1 0.015 5 thru 7 0.01 I 0.015 NOTE(

39、a)W HINIMW I/8 3/16 I/4 5/16 318 7/16 Il2 9/16 518 M I N I M I I I I I 5 w .O25 050.O50 I.I.O25 I-050 I.O50 THE MANUFACTURER MAY NEED TO REVISE DIAMETRICAL CLEARANCES FOR SEVERE SERVICES AND/OR HIGH PRESSURE APPLICATIONS.3 COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLice

40、nsed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD*flSS SP-120-ENGL 1997 W 5770bY0 0500928 205 SP-120 MSS STANDARD PRACTICE TABLE IM-PACKING SYSTEM DETAILS(METRIC UNITS)DIAMETRICAL CLEARANCE-MAXIM

41、Uk NOTE:DIMENSIONS I N MILLIMETERS WIDTH&DEPTH O PACKING-0.51 I.o;I.o;I.o;0.51 I.o;0.64 I.2 I.2 17.5 fhru 31.8 127.0 thru 178.0 I 0.38 I 15.9 I 5 W O:6 4 -0.64 I.27 I.27 I.27 I,27 0.76-0.76 I.65 _ I.65 I.65 1.65 3.76 I.65 I.65 _ I.65 3.76-I.65-NOTE(a)THE MANUFACTURER MAY NEED TO REVISE DIAMETRICAL C

42、LEARANCES FOR SEVERE SERVICES AND/OR HIGH PRESSURE APPLICATIONS.COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD-MSS

43、SP-L20-ENGL 1777 5770bYO 0500727 LYL STANDARD PRACTICE SP-120 MSS m-4 1-g GASKET SURFACE TYPICAL BONNET TYPICAL STEM FIGURE 1 STEM/BONNET DETAILS(U.S.UNITS)5 COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Stan

44、dardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD*MSS SP-IZO-ENGL I777 5770bll0 0500730 7b3 MSS STANDARD PRACTICE SP-120 0-4 1-GASKET SURFACE TYPICAL BONNET TYPICAL STEM FIGURE 1M STEM/BONNET DETAILS(METRIC UNITS)6 COPYRIGHT Manufacturers Standardization Socie

45、ty of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD-MSS SP-120-ENGL 1997 5770b110 0500933 BTT W MSS STANDARD PRACTICE SP-120 x P H+b I,0 DATUM FEATURE SYMBOL DEF.-A

46、DATUM FEATURE SYMBOL I S USED TO DESIGNATE A DATUM SURFACE OR FEATURE.CYLINDRICITY DEF.-CYLINDRICITY I S A CONDITION OF A SURFACE OF REVOLUTION I N WHICH ALL POINTS OF THE SURFACE ARE EQUIDISTANT FROM A COMMON AXIS.POSITION DEF.-A POSITION TOLERANCE DEFINES A ZONE WITHIN WHICH THE AXIS OR CENTERPLAN

47、E OF A FEATURE I S PERMITTED TO VARY FROM ITS THEORETICALLY EXACT POSITION.PERPENDICULARITY DEF.-PERPENDICULARITY I S THE CONDITION OF A SURFACE,AXIS OR LINE WHICH I S 9 0 FROM A DATUM PLANE AXIS.MAXIMUM MATERIAL CONDITION DEF.-MAXIMUM MATERIAL CONDITION I S THAT CONDITION WHERE A FEATURE OF SIZE CO

48、NTAINS THE MAXIMUM AMOUNT OF MATERIAL WITHIN THE STATED LIMITS OF SIZE.e.g.SMALLEST HOLE;BIGGEST SHAFT.FIGURE 2 GEOMETRIC SYMBOL DEFINITIONS 7 COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Soc

49、iety of the Valve and FittingsLicensed by Information Handling ServicesSTD*MSS SP-120-ENGL 1997 5770b40 0500932 73b MSS STANDARD PRACTICE SP-120 ANNEX A REFERENCED STANDARDS This annex is an integral part of this Standard Practice which is placed after the main text for convenience.ASME PUBLICATIONS

50、(Approved as American National Standards)ASME B16.34-1996 Valves-Flanged,Threaded,and Welding End MSS PUBLICATIONS SP-96-1996 SP-99-1994 SP-105-1996 SP-12 1-1997 Guidelines on Terminology for Valves and Fittings Instrument Valves Instrument Valves for Code Applications Qualification Testing Methods