1、MIL-V-20065D(SHIPS) 8 June 1967 MIL-V-200GFjC(SHIPS) 8 July 1959 (See 6.3) SUPERSEDING MILITARY SPECIFICATION VALVES, ANGLE, PRESSURE RELIEF. NAVAL SHIPBOARD, FOR STEAM SERVICE 1. SCOPE 1.1 Scope. - - This specification covers spring loaded pressure relief valves for steam service. 1.2 classificgtjo
2、ll. - Pressure relief valves shall be of the following types and compositions as specified (see 6.2): Qpe I - Atmospheric outlet Type II - Pressuretight outlet Composition A: Chromium - 2 -1 .!4 percent Molybdenum - 1 percent Chromium - 1-1s.4 percent Molybdenum - li2 percent Composition B: Composit
3、ion D: Carbon steel 2. APPLICABLE DOCUMENTS 2. 1 The following documents of the issue in effect on date of invitation for bids or request for proposal, form a part of this specification to the extent specified herein. SPECIFICATIONS FEDERAL QQ-N-288 - Nickel-Copper Alloy and Nickel-Copper-Sillicon A
4、lloy Castings. MILITARY MIL-S-901 - Shock Tests, H. I. (High-Impact); Shipboard Machinery, Equipment and MIL-D-1000i2 - Drawings, Engineering and Associated Lists. MIL-R-17131 - Rods, Welding. Surfacing. MIL-S-23192 - Springs. Helical. Age-Hardenable Nickel-Chromium-Iron Alloy. Systems, Requirements
5、 for. STANDARDS MILITARY MIL-STD-167 - Mechanical Vibrations of Shipboard Equipment. MIL-STD-798 - Nondestructive Testing, Welding, Quality Control. Material Control and Identification and Hi-Shock Test Requirements for Piping System Com- ponents for Naval Shipboard Use. (Copies of specifications, s
6、tandards, drawings, and publications required by suppliers in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer. ) 2.2 Other publications. - The following documents form a part of this specification to the extent s
7、peci- fied herein. Unless otherwise indicated, the issue in effect on date of invitation for bids or request for proposalshall apply. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) A68 - Carbon-Strcl
8、 Bards Cor Springs. A105 - Forged or Rollcd Secl Pipe Flanges. Forgcd Fittings, and Valvcs and Parts for High- Tetnperature Service. A182 - Forged or Rolled Alloy-Steel Pipe Flanges, Forgcd Fittings and Valves and Parts for High Temperature Service. A193 - Alloy-Steel Bolting Materials for High Temp
9、erature Service. A194 - Carbon and Alloy Steel Nuts for Bolts for High-pressure and High-Temperature Service. A216 - Carbon Steel Castings Suitable for Fusion Welding for High-Temperature Service. A217 - Alloy Steel Castings for Pressure Containing Parts Suitable for High-Temperature Service. A230 -
10、 Carbon-Steel Valve Spring Quality Wire. A231 - Chromium-Vanadium Alloy Steel Spring Wire. A232 - Chromium-Vanadium Alloy Steel Valve Spring Quality Wire. A276 - Hot-Rolled and Cold-Finished Stainless and Heat Resisting Steel Bars. A351 - Ferritic and Austenitic Steel Castings for High-Temperature S
11、ervice. B164 - Nickel-Copper Alloy Rod and Bar. (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, Pa. 19103.) UNITED STATES OF AMERICA STANDARDS INSTITUTE (USAS) B1.12 - Class 5 Interference-Fit Thread. B16.5 - Steel Pipe F
12、langes and Flanged Fittings. (Application for copies should be addressed to the United States of America Standards Institute, 10 East 40th Street, New York, New York 10016.) THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) Boiler and Pressure Vessel Code. (Application for copies should be address
13、ed to the American Society of Mechanical Engineers, 345 East 47th Street, New York, New York 10017,) NATIONAL BUREAU OF STANDARDS Handbook H28 - Screw-Thread Standards for Federal Services. (Application for copies should be addressed to the Superintendent of Documents, Government Printing Office, Wa
14、shington, D. C. 20402.) OFFICIAL CLASSIFICATION COMMITTEE Uniform Freight Classification Ratings. Rules and Regulations. (Application for copies should be addressed to the Official Classification Committee, 1 Park Avenue at 33rd Street, New York, New York 10016. ). 3. REQUIREMENTS 3.1 Definitions. -
15、 The following definitions are applicable to this specification. 3.1.1 Set pressure. -The pressure at which the valve pops. Expressed in pounds per square inch gage (Psig). 3.1.2 Set pressure tolerance. - The permissible plus or minus deviation from the specified set pres- sure. Expressed in pounds
16、per square inch (psi) or as a percent of the set pressure. 3.1.3 Set pressure range. - The range over which the set pressure can be adjusted with the installed spring. 3.1.4 Accumulation. - The increase in pressure, above the set pressure, required to pass rated flow. Expressed in psi or as a percen
17、t of the set pressure. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-20065D(SHIPS) 3.1.5 Accumulation pressure. - The set pressure plus the accumulation. Expressed in pig. - 3.1. G Blowdow!. - The decrease in pressure, below the set pressur
18、e, required for the valve to re- seat. Expressed in psi or as a percent or the set pressure. The accumulation and blowdown estah- lish the operating band of the relief valve at a particular setting. 3.1.7 Blowdown pressure. - The set pressure minus the bbwdown. Expressed in psig. - . . . . . - - . “
19、_ “ . - “ 3.2 Valve description. - This specification covers self-contained, single seated, spring loaded relief valves, wkre the inij-efprssure is sensed under and directly operates the spring loaded disc. 3.3 -MaterialS.of construction. - Materials shall be as specified in table I. All materials s
20、hall be selected to prevent galling, seizing, or excessive wear between parts. Clearances shall be such as to prevent interferences due to thermal expansion. Table I - List of Materials / Name of Parts . ._ “ - _“_ _ Composition A Body, bonnet, and 1 ASTM A182 grade F22 ASTM A182 grade F11 Compositi
21、on B Composition D yoke ! ASTM A217 grade WC9 ASTM A217 grade WC6 ASTM A216 grade WCB ASTM A105 grade II I ASTMA217grade WC1, WC6 I i ASTM A351 grade CF3, 1 CF31, CF$, CF8M - Disc and seat ring i Haynes 25 or Stellite 1 Same as for Composition A! ASTM A276 types 302, . (wrought Stellite 6B, t 303, 3
22、04, 316, 431, 440 cast Stellite 6 or an in- i i ASTM A351 grades CF3, j lay of Stellite not less f CFSM, CF8, CF8M , than 3/32 inch thick. 1 ! ASTM B164 i Where inlays are used, ! QQ-N-288 ! welding rod shall be in ! accordance with type i i MIL-RCoCr-A of MIL-R-17131 and base i materials shall be o
23、ne of the following: ASTM : t A351 grade CF3, CFSM,: I ASTM A276 types 302, i i E ! 304, 316, 347). Sem I CR 13 Springs I MIL-S-23192 “- i ! CR 13 1 CR 13 .I MIL-S-23192 1 MIL-S23192 i ASTM A68 Body bolts and nuts ASTM A193 grade B16 ASTM A194 grade 4 I ASTM A193 grade ASTM A194 grade B14 or B16 2H
24、or 4 ASTM A193 grade ASTM A194 grade B7 or B16 2H or 4 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-20065D( SHIPS) 3.4 Design and construction requirements. - 3.4.1 grf%ssureItem$erature ratings. - The design and pressure-temperature ratin
25、g for valves of this specification shall be in accordance with USAS B16.5. Maximum temperature limitations shall be as fol- lows: Composition A - 1050F Composition B - 1000F Composition D - 775F The outlet and spring housing for type II valves shall be designed to withstand the higher of the followi
26、ng: (a) 150 percent of maximum system back pressure. (b) 150 pound USAS rating. 3.4.2 End connections. - Valve inlet and outlet connections shall be flanged in accordance with USAS B16.5. 3.4,3 Body coastruction. - The valve shall be designed and constructed so that the seat will not become distorte
27、d, relative to the disc, and valve operation is not adversely affected by internal pressure. 3.4.4 Bonnet construction. - The bonnet shall be flanged for attachment to the body. Sufficient bolting area shall be provided to maintain a leakproof joint over a three year period, Bearing surfaces of nuts
28、 and bolts and their respective mating surfaces on the valve, shall be finished machined. 3.4.5 Seat rings. -A seat ring shall be provided which is seal welded or silver brazed circumferentially to the body. When the seat ring is part of the inlet flange raised face, such as in full nozzle valves, n
29、o welding or brazing is required. 3.4.6 Stem and disc. - The stem or stem and disc assembly shall be top guided. Guiding surfaces shall have the proper hardness, finish, concentricity, parallelism, clearance, length, and rigidity to pre- vent binding or seizing due to lateral thrust or thermal expan
30、sion, and to insure proper seating. These requirements shall be maintained with interchangeable parts. 3.4.7 Springs. - Springs shall be designed so that they will not be fully compressed or stressed beyond 2/3 of the yZiZFength of the spring material under any normal operation or adjustment of the
31、valve. The working stress shall be such that relaxation shall not exceed 5 percent over a 1000 hour period at the oper- ating temperature. When removed and compressed solid, the springs shall not exhibit a permanent set ex- ceeding 0.010 inch per inch of free spring length, measured 10 minutes after
32、 release of the spring. Spring ends shall be squared and ground, _. 3.4.8 Threads. -All threads shall conform to Handbook H28. Provisions shall be incorporated to pre- vent the accidental loosening of all threaded parts; Unless otherwise specified in the contract or order, bolt- ing shall be class 2
33、 fit. When tap-end studs are used, the tap end shall have an interference fit in accord- ance with USAS B1.12. Pipe threads shall not be used. 3.4.9 Interchangeability. -All parts having the same manufacturers part number shall be directly interchangeable with each other with respect to installation
34、 and performance and should not require selec- tion, fitting, or machining of any kind. Where machining is required after installation of a seat ring or guide in order to maintain critical concentricity or alignment dimensions, detailed instructions must be provided with each spare part. 3.4.10 Hand
35、 lifting device. - Valves shall be designed so that they may be operated by hand for testing purposes with an inlet pressure of 75 percent of the set pressure. The necessary lever or tool shall be furnished as part of each valve. 3.4.11 Stuffing boxes. -A stuffing box on the valve stem shall not be
36、permitted. A stuffing box on the shaft of a hand lifting device, which will have no effect on the relief valve setting, shall be required on type II valves. 4 :. g .- ” Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.4. I2 Gagging device. - Where r
37、equired for system test purposcs, a gagging device shall he Specified to be supplied with the valve ( see G. 2) . Valves shall be capable of being gagged without alteration of the set pint. The gagging screw shall be provided with a knurled or wing nut-type head to discourage the use of wrenches whe
38、n gagging the valve. The gagging device shall be designed to minimize the possibility of overlooking its removal after test and shall include a tag or other warning to this effect. 3.4.13 Accessibility. -Valves shall be accessible for adjustment and repair without requiring removal from the line. 3.
39、4. 14 Valve adjustment. - Means shall be provided for adjusting the setting with the valve under pres- sure. The adjusting screw shall have right hand threads so that clockwise rotation increases the set pres- sure. The adjusting device shall be provided with a locknut and cap, or other suitable mea
40、ns, to prevent accidental change of adjustment. 3.4.15 Type I valve requirements. - Type I valves shall have exposed springs. The clearance between the stem and the bonnet shall be sufficiently close to minimize the escape of steam between the stem and bonnet while the valve is relieving. 3.4.16 Typ
41、e II valve requirements. - Type II valves shall be pressuretight on the outlet side. The pressure-temperature rating for the valve outlet shall be in accordance with 3.4.1. 3.5 Performance requirements; - 3.5.1 Range of adjustment.“ For set pressures up to 250 psig, the set pressure shall be adjusta
42、ble over a range of plus or minus 10 percent and forset pressures over 250 psig, the set pressure shall be adjustable over a range of plus or minus 5 percent, without requiring replacement of any internal parts. 3. 5.2 Operation. - Where properly installed in accordance with limitations specified by
43、 the valve manu- facturer, relief valves shall operate over entire flow range without chatter. Valve lift shall be sufficient to prevent wire drawing. Valves shall open with a clear sharp pop at the pressure for which they are set. Valve closure shall be clean and sharp when the inlet pressure is re
44、duced to the blowdown pressure, after the valve has passed full rated flow .or any intermediate flow. 3.5.3 Set pressure tolerance. - The set pressure tolerance, plus or minus, shall not exceed 2 psi or 2 percent of the set pressure, whichever is greater. 3.5.4 Accumulation. - Valves shall be sized
45、to pass the capacity specified (see 6.2) without permitting the inlet pressure to exceed the accumulation limit specified in figure 1. 3.5. 5 Blowdown. - Valves shall operate satisfactory with a blowdown setting not exceeding that permit- ted by figure 1. 3.5.6 Seat tightness. - With an inlet pressu
46、re equal to the minimum allowable blowdown pressure, there shall be no visible evidence of steam leakage when the outlet is viewed against a dark background. 3.5.7 Installation limitations. - Unless otherwise specified (see 6. 2), valve operation shall not be adversely affected by an inlet pressure
47、loss up to 25 percent of the relief valve blowdown, a discharge pressure buildup up to 10 percent of the set pressure or both. Where the installation will subject the valve to greater piping restrictions, this information must be included in the ordering data. 3.6 Mechanical shock and vibration. - V
48、alves shall be designed to meet the mechanical shock require- ments of MIL-S-901 and vibration requirements of MIL-STD-167. Requirements for shock and vibration testing shall be as specified (see 6.2). . 3.7 Marking. - 3.7.1 Body markings. - The manufacturers name or trademark and the body material
49、composition shall be cast or forged integral with the valve body. The size and USAS pressure rating (inlet and outlet) shall be cast or forged integral with the valve body or stamped on the O. D. of the flanges. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-x .- . / / . 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.7.2 Identificati
