MSS SP-88-2015 Diaphragm Valves.pdf

1、MSS SP-88-2015 Diaphragm Valves Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 Fax: (703) 281-6671 E-mail: standardsmsshq.org www.msshq.org MSS STANDA

2、RD PRACTICE SP-88i This MSS Standard Practice was developed under the consensus of the MSS Technical Committees 406 and the MSS Coordinating Committee. The content of this Standard Practice is the resulting efforts of competent and experienced volunteers to provide an effective, clear, and non-exclu

3、sive standard that will benefit the industry as a whole. This MSS Standard Practice describes minimal requirements and 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 manufactu

4、re, sale, or use of products not conforming to the Standard Practice. Mandatory conformance to this Standard Practice is established only by reference in other documents such as a code, specification, sales contract, or public law, as applicable. MSS has no power, nor does it undertake, to enforce o

5、r certify compliance with this document. Any certification or other statement of compliance with the requirements of this Standard Practice shall not be attributable to MSS and is solely the responsibility of the certifier or maker of the statement. “Unless indicated otherwise within this MSS Standa

6、rd Practice, other standards documents referenced to herein are identified by the date of issue that was applicable to this Standard Practice at the date of approval of this MSS Standard Practice (see Annex B). This Standard Practice shall remain silent on the validity of those other standards of pr

7、ior or subsequent dates of issue even though applicable provisions may not have changed.” By publication of this Standard Practice, no position is taken with respect to the validity of any potential claim(s) or of any patent rights in connection therewith. MSS shall not be held responsible for ident

8、ifying any patent rights. Users are expressly advised that determination of patent rights and the risk of infringement of such rights are entirely their responsibility. In this Standard Practice, all text, notes, annexes, tables, figures, and references are construed to be essential to the understan

9、ding of the message of the standard, and are considered normative unless indicated as “supplemental”. All appendices, if included, that appear in this document are construed as “supplemental”. Note that supplemental information does not include mandatory requirements. U.S. customary units in this St

10、andard Practice are the standard; the SI (metric) units are for reference only. Substantive changes in this 2015 edition are “flagged” by parallel bars as shown on the margins of this paragraph. The specific detail of the change may be determined by comparing the material flagged with that in the pr

11、evious edition. Excerpts of this Standard Practice may be quoted with permission. Credit lines should read Extracted from MSS SP-88-2015 with permission of the publisher, Manufacturers Standardization Society of the Valve and Fittings Industry. Reproduction and/or electronic transmission or dissemin

12、ation is prohibited under copyright convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry Inc. All rights reserved. Originally Approved: January 1978 Originally Published: July 1978 Current Edition Approved: August 2015 Curren

13、t Edition Published: December 2015 MSS is a registered trademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright , 2015 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-88ii TABLE

14、OF CONTENTS SECTION PAGE PURPOSE 1 1 SCOPE . 1 2 PRESSURE-TEMPERATURE RATINGS . 1 3 DIAPHRAGMS . 2 4 BODY-BONNET JOINTS 2 5 BODY MATERIALS 3 6 BONNETS . 3 7 BODY FACE-TO-FACE DIMENSIONS . 3 8 BODY END CONNECTIONS AND WALL THICKNESS . 3 9 ACTUATOR APPLICATION REQUIREMENTS . 4 10 SHELL TESTS 4 11 SEAT

15、 TESTS . 5 12 MARKING 5 TABLE A1 Maximum Service Pressure-Ratings at 100 F (38 C) for Category B Valves (Standard Valves Section 2.2) 6 A2 Commonly Used Face-to-Face Dimensions of Flanged Diaphragm Valves . 7 A3 Standards Applicable to Body Wall Thickness and the Dimensions of Threaded, Flanged, and

16、 Butt Weld Body End Connections (Category A and Category B Valves Only) . 8 A4 Body Material Standards 9 A5 Test Durations and Test Pressures Based on Diaphragm Maximum Service Pressure Ratings Shown in Table A1 10 ANNEX A Tables . 6 B Referenced Standards and Applicable Dates 11 MSS STANDARD PRACTI

17、CE SP-881 DIAPHRAGM VALVES PURPOSE The purpose of this Standard Practice is to outline the limitations and requirements of valves in which a nonmetallic, resilient diaphragm is used to separate the working parts of the valve from the line fluid and also functions in conjunction with other parts as v

18、alve closure-member. The use of a nonmetallic, resilient diaphragm causes valves described in this Standard Practice to be different from other commonly used valves for which general and specific Standards and Standard Practices are in existence. These differences include pressure-temperature limita

19、tions, face-to-face dimension requirements, and specific service characteristics. This Standard Practice reflects industry practice in the design, manufacture, and application of this type of valve. 1. SCOPE 1.1 This Standard Practice applies to valves for general liquid and gas service that effect

20、valve closure by means of a resilient diaphragm sealing against a weir or a diaphragm acting in conjunction with a separate or integral disk-member sealing against a seat, having equal sealing capability in either flow direction, and having diaphragms being essentially made of elastomeric or plastic

21、 material or combinations thereof. 1.2 This Standard Practice defines the following categories of valves: a) Class 125 or 150 Valves (see Section 2.1) b) Standard Valves (see Section 2.2) c) Valves for Special (Low Pressure) Applications (see Section 2.3) The purchaser, when referencing the Standard

22、 Practice, shall also specify the appropriate category as listed above. 1.3 This Standard Practice covers the following: a) Pressure-Temperature Ratings and Design Requirements b) Commonly Used Diaphragm Pressure Limitations c) Body, Bonnet, and Bolting Materials d) Commonly Used Face-to-Face Dimens

23、ions for Flanged Valves e) Body End Connections and Wall Thicknesses f) Actuator Application Requirements g) Tests h) Marking 1.4 For specific requirements relating to the dairy industry, refer to 3-A SSI 54-02. MSS STANDARD PRACTICE SP-882 2. PRESSURE-TEMPERATURE RATINGS 2.1 Category A Valves (Clas

24、s 125 or 150) The maximum non-shock pressure-temperature ratings of valve bodies for valves in this category shall be those specified in the applicable Standards referenced in Table A3, Annex A, and the valve bodies must conform to the applicable requirements of the referenced standards (see Section

25、s 2.4 and 2.5 for service ratings of the diaphragms). 2.2 Category B Valves (Standard Valves) The maximum non-shock pressure-temperature ratings of valves in this category shall be those listed in Table A1, Annex A. Body wall thicknesses shall be those established by the applicable requirements of t

26、he referenced standards in Table A3, Annex A. 2.3 Category C Valves (Special Valves, Low Pressure) The maximum non-shock pressure-temperature ratings of valves in this category shall be those established by the manufacturer for the particular design. 2.4 The actual service pressure-temperature ratin

27、g of the assembled diaphragm valves shall be limited to the pressure-temperature rating of the body or the diaphragm, whichever is lower, as outlined in Section 2.5. 2.5 The service ratings of the diaphragms shall be those established by the valve manufacturer for the design and material selection f

28、or the intended service. Maximum allowable temperatures for elastomeric, plastic, or combined elastomeric and plastic diaphragms vary with the manufacturers design and the material composition, therefore, standard values cannot readily be established. In order to enable the manufacturer to make prop

29、er recommendations regarding diaphragm and valve type and material selection, the following conditions shall be provided by the user: a) Valve Size b) Pressure c) Temperature d) Medium Handled, including Concentrations of Acids or Bases e) Mode and/or Frequency of Operation f) Flow Rate g) Line Shoc

30、k Conditions h) Vacuum i) Use of Line Cleaning Fluids j) Submersion of Valve 3. DIAPHRAGMS 3.1 Diaphragm materials shall be as recommended by the valve manufacturer for the intended service, considering the limitations, as outlined in Section 2.5. 3.2 Diaphragms are dimensionally not interchangeable

31、 between the various diaphragm valve designs made by different manufacturers. Replacement diaphragms must be purchased for a specific model of a valve manufacturer to assure the proper dimensional fit. 3.3 Diaphragms determine the service rating of diaphragm valves in most cases, as outlined in Sect

32、ions 2.4 and 2.5. Therefore, if a replacement diaphragm is being used that does not show the valve manufacturers name, initials, or easily identifiable trademark, the valve service-ratings established by the valve manufacturer are invalid. MSS STANDARD PRACTICE SP-883 4. BODY-BONNET JOINTS 4.1 Body-

33、bonnet joint bolting shall be designed to meet the allowable bolting stress specified in ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, at 100 F (38 C) for the bolting material being used. 4.2 Carbon steel bolts or studs shall meet the minimum mechanical and the chemical property re

34、quirements of ASTM A307, Grade A or B. 4.3 Stainless steel bolts or studs, when specified by the customer, shall meet the minimum mechanical and the chemical property requirements of ASTM A193, Grade B8. 4.4 Alloy steel bolts or studs, when specified by the customer or when required in Category A va

35、lves, shall meet the minimum mechanical and the chemical properties requirements of ASTM A193, Grade B7. 4.5 Other corrosion resistant body-bonnet bolt or stud materials or other body-bonnet fastening methods are not covered by this Standard Practice. 5. BODY MATERIALS Body materials shall conform t

36、o the standards referenced in Table A4, Annex A. Non-listed materials such as special alloys and plastics are not covered by this Standard Practice and are subject to agreement between customer and manufacturer. 6. BONNETS 6.1 The bonnets of manually operated valves shall be capable of withstanding

37、the hand wheel closure forces and fill-pressure loading in the event of a diaphragm failure. 6.2 The bonnets of valves with actuators must be, in addition to the requirements of Section 6.1, capable of withstanding mechanical stresses induced by the weight of actuators or any other auxiliary equipme

38、nt in all possible valve installation positions. 6.3 Except as provided in Sections 6.4 and 6.5, bonnet material shall be cast iron, malleable iron, ductile iron, or cast steel at the manufacturers option, regardless of body materials, unless one of these bonnet materials is specified by the custome

39、r or a different bonnet material is agreed upon between customer and manufacturer. 6.4 When the customer specifies a pressure-retaining bonnet for Category A valves with body pressure-temperature ratings for Class 125 or 150, the bonnet shall conform to the wall section and material requirements of

40、the standards listed in Table A3, Annex A. 6.5 Plastic bonnets are permissible when specified by the customer. Plastic bonnets shall be designed and qualified in accordance with ASME B31.3, Section A304.7. 6.6 The seal of the sealed bonnets, when specified by the customer, shall be designed to conta

41、in line pressure or vacuum in the event of diaphragm failure. 7. BODY FACE-TO-FACE DIMENSIONS Face-to-face dimensions of flanged diaphragm valves and valve centerline-to-top dimensions are peculiar to the particular manufacturers design. Consult each manufacturer for specific dimensions. Commonly us

42、ed face-to-face dimensions of flanged diaphragm valves are given in Table A2, Annex A, for the guidance of diaphragm valve users. MSS STANDARD PRACTICE SP-884 8. BODY END CONNECTIONS AND WALL THICKNESS 8.1 Body end connections shall conform to the standards referenced in Table A3, Annex A. 8.2 Body

43、wall thicknesses of Category A and B valves, shall conform to the standards referenced in Table A3, Annex A, for Classes 125 and 150. 8.3 Body wall thicknesses of Category C valves specifically designed and marked for pressure ratings lower than those specified in Sections 2.1 and 2.2 shall be the m

44、anufacturers standard. 9. ACTUATOR APPLICATION REQUIREMENTS 9.1 Manually operated valves shall be actuated by handwheels or quick-opening levers with counter clockwise rotation to open the valve. Different means of manual actuation can be specified after agreement between customer and manufacturer.

45、9.2 Handwheels shall be of sufficient diameter to ensure tight, manual closure at the specified service pressure of the valve. 9.3 Handwheels shall be marked with the direction of movement for opening the valve. 9.4 Pneumatic, hydraulic, pneumatic spring return, hydraulic spring return, or electric

46、actuators shall be sized to be capable of closing the valve against a minimum of 1.1 times the maximum service pressure rating of the valve. In case the actual shutoff pressure specified by the customer is lower than the maximum service pressure rating of the valve, the actuator may be sized to be c

47、apable to close against a minimum of 1.1 times the actual shutoff pressure with the customers approval(1). 9.5 Available air or hydraulic pressure or electric current data must be specified by the customer. 10. SHELL TESTS 10.1 Each Category A Class 125 or 150 diaphragm valve body shall be hydrostat

48、ically tested at 1.5 times maximum working pressure specified in the applicable Standard referenced in Table A3, Annex A. Each Category A Class 125 or 150 diaphragm valve bonnet shall be hydrostatically tested with the same pressure as the valve body, when specified by the customer, and may be teste

49、d simultaneously with the body by using a gasket in place of a diaphragm. 10.2 Each Category B diaphragm valve having a service pressure established in accordance with Section 2.2 shall receive a hydrostatic or air shell test in accordance with Table A5, Annex A, with the valve in the full open position. Each bonnet for Category B valves shall be hydrostatically tested with the same pressure as the valve body, when sealed bonnet and testing is specified by the customer. Bonnet test method shall be at the option of the manufacturer. 10.3 Each Category C diaphragm valve