1、MILITARY SPFCIFICATTON VALVE, SAFETY: BOSLEH (SHIPBQAqD USE) This specification is approved for qse by the Naval Sea Systems Commend, DepartmeRb of the Navy, gnd is aygila8le far u8e by alJ. Departments and Agencie$ of the Departmeht of Defense, 1. SCOPE I This speoificatloc cgverg l-l/j?-jnb and 2-
2、1/2-inch for steam drum and 8yperheater iervice at working pressures of 600 and 1500 pounds per square inch (ib/i?lz), r 1.2 Classification, Safety valvefi shg,L be of the folowing types, 1 c 1 aase s , and q i je 8, -pea i fi e4 se e. 6.2.1 : P Type I - Flanged, direct apr4ng loaded, POP typa, Type
3、 XI - Flanged, steam drum pilot actiiator, Type III Flanged, svperheab$r outL%t pilof actuated- Class 1 - 600 lb/in2 service. Clags 2 - 1300 lb/in2 servies, Size i - rl/2-inch. Size 2 - 2-1/2-inqh. 2, APPI,.ICpBLE DOCUMENTS 2.1 IssUes of documents, The fol$owing dpcuments, of the issue in effect on
4、dqte pf ifvitation fpr bids or rsqire$t for praposal, form a part of this specjfication to $he extetlit speoifie# heretn. O i I f SPECIFICATIONS MILITARY MIL-V-3 - Valveq, Fittings, and Flanges (Except for Systems MIL-R-196 - Repair farta, Accessoriqa, ,and Kits, Mechanical; Indtated Herein); Packag
5、ing of. Pgckaging Qf* Beneficial comments (recormendatlons, qdd.itigns, geletiona) ,?nd any pertinent data which may be of uae in impraving this document should be addressed to: Commander, Naval Sea Syateng -Command, SEA 31 12 , Department of the Navy, Washington, RC 20362 b using the self-addressed
6、 Standardization Document Improvement Propos84 DD Form 1426) appearing at the end of thks document or by letter. FSC 4820 THIS DOCUMENT CONTAINS /b PAGES. i Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-174629 4 m 7777706 0272336 5 m MILITARY
7、 (Continued) MIL-S-901 - Shock Test3, (High-Impact) ; Shipboard Machinery, Equipment and Systems, Requirements for. MIL-S-1222 - Studs, Bolts, Hex Cap Screws,. and Nuts, MIL-P-15024 - Plates, Tags and Bands for Identification MIL-P-15024/5 - Plates, Identification, MIL-J-45208 - Inspecti,on System R
8、equirements, of Equipment. STA NDA RDS F EDE RA L FED-STD-H28 - Screw-Thread Standards for Federal Services. MILITARY MIL-STD-271 - Nondestructive Testing Requirements for MIL-STD-278 - Fabrication Welding and Inspection: and -. Metals. Casting Inspection and Repair for Machinery, Piping, and Pressu
9、re Vessels in Ships of the United States Navy. DRAWING NAVAL SEA SYSTEMS COMMAND NAVSHIPS 5000-S51O3-841622 - Valves, Boiler Safety, 300, 600, and 1500 Psi Nominal Pressure, Dimensional Standard for. (Copies of specifications, standards, drawings, and QUbliCabiOnS required by oontractors in connecti
10、on with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting officer .I 2.2 Other publications. The following documents form a part of this specification to the extent specified hePein. Unless otherwise indicated, the issue in effect on da
11、te of invitation for bids or request for proposal shall apply. AMERICAN SOCIETY FOR TESTING AND MAT.ERIALS (ASTM) A 182 - Forged or Rolled Alloy-Steel Pipe Flanges, Forged A 216 - Carbon-Steel Castings Suitable for FusiQn Welding for A 217 - Martensitic Stainless Steel and Ally Steel Castings Fittin
12、gs, and Valves and Parts for High Temperature Service. Hig h-Temper atur e Service, for Pressure-Containing Pgr ts Suitable for High Temperature Service. (Applications for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103,) AMERICA
13、N NATIONAL STANDARDS INSTITUTE (ANSI) B16.5 - Steel Pipe Flanges, Flanged Valves, and Fittings. 2 Y Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- 4 MIL-V-17Vh2B VB II 7779706 0272337 7 W (Application for copies shoilld be addressed to the American
14、 National Standards Institute, Inc., 1430 Broadway, New York, NY 10018.) (Technical society and technical association specifications and standards are generally available for reference from libraries. They are also distributed among technical groups and using Federal agencies. I 3. REQUIREMENTS 3.1
15、Qualification. Valves furnished under this specification-shall be products which are qualified for listing on the applicable qualified products list at time set for opening of bids (see 4.3 and 6.3). 3.2 Material. Materials used ir. the construction of safety valves shall be of the quality best suit
16、ed for the purpose intended. Material of bodies, bonnets, and bolt-studs or studs and nuts for inlet flanges and bonnets shall be as specified herein. The suitability of the material of all other parts shall be demonstrated by satisfactory performance of . the valves when tested as specified herein
17、and in service. 3.2.1 Bodies. Bodies of all safety valves shall be fabricated from ? the applicable grade or composition of material as follows: 1 For maximum steam drum pressure of 750 lb/in2 (class I), type I or type II, material shall be of cast steel conforming to ASTM A 216. For maximum steam d
18、rum pressure of 1600 lb/in2 (class 21, or maximum steam temperature of 875OF, material shall be of carbon molybdenum steel conforming to grade F1 of ASTM A 182 or grade WC1 of ASTM A 217; or of chromium molybdenum steel conforming to grades WC6 or WC9 of ASTM A 217 or grades F11 or F22 of ASTM A 182
19、. (at any pressure), material shall be of chromium molybdenum steel (weldable grade) conforming to grades WC6 or WC9 of ASTM A 217 or to grades F11 or F22 of ASTM A 182, or better. For superheated steam temperatures exceeding 975OF, material shall be of chromium molybdenum alloy steel or corrosion-
20、resisting steel of a composition satisfactory to the command or agency concerned. For superheated steam temperatures between 875OF and 975OF 3.2.2 Bqnnets. Bonnet material shall be in accordance with the fol lowing : E (a) Steam drum valve bonnets shall be of the same material as specified in 3.2.1.
21、 (b) Materials for superheater outlet spring loaded valve bonnets shall have a low mean coefficient of thermal expansion (less than 7.95 x in/in/OF). Where required, use of -cooling spools or other means to reduce thermal effects may be used. 3 Provided by IHSNot for ResaleNo reproduction or network
22、ing permitted without license from IHS-,-,- MIL-V-L74b2B 48 a 799990b 02723389 M MIL-V-l7462B( SH) 3.2.3 Bolts, studs, and nuts. Bolts, studs, and nuts shall conform to MIL-S-1222. In general, the following shall apply: (a) Up to 650F, use material grade 5 for bolting. (b) Up to 850F, use material g
23、rade B7 for bolting, (c) Up to 1000F, use material grade B16 for bolting and 2H for nuts. 3.2.4 Nozzles, discs, and adjusting rings. Nozzles, discs, and ad justin.g- rings shall be made from corrosion-resisting materials suitable for the service intended. 3.2.5 Recovered materials. Unless otherwise
24、specified herein, all equipment, material, and articles incorporated in the products covered. by this specification shall be new and shall be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing the intended use. The term “recovered mate
25、rialsf1 means materials which have been collected or recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. None of the above shall be interpreted to mean that the use of used or rebuilt products is allowed under this specification unless
26、otherwise specifically specified. t 3.3 General construction and design. 3.3.1 Safety valves shall be constructed and shall operate so that shocks detrimental to the valves or to the boiler are minimized when F lifting or closing. 3.3.1.1 Valves shall withstand maximum expected loading in any direct
27、ion which shall include the load which may be applied by the escape piping (i.e., expansion and reactive force of the steam with the valve blowing) while remaining within valve pop, repeatability, performance, .or leakage limits. 3.3.1.2 A temporary metal tag shall be affixed to the bolt holes of ea
28、ch valve exhaust flange, engraved with the following statement: “Minimize valve exhaust flange loading by adjusting exhaust piping and expansion joints for no-load condition when the boiler is hot and boiler expansion has stabilized .I 3.3.2 The blowdown of all safety valves shall be adjustable over
29、 a range of from 2-1/2 to 6 percent of the design popping pressure. Clear and complete adjustment instructions shall be included in the manufac- turer s maintenance manual. 3.3.3 The design of tne bonnet, blowdown adjusting device, and valve disc shall be such as to minimize back pressure in the val
30、ve body acting upon the valve disc, 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I MIL-V-L7462B 48 m 9393906 0272333 O m MIL-V-l7462B( SH) I III I and III II 3.3.3.1 It shall be possible to remove or install the lifting gear bracket assembly wit
31、hout disturbing the tightness of the bonnet. To accomplish this, the bonnet studs which receive the lifting gear bracket shall be of suitable length to accommodate the bonnet nut, bracket, and bracket securing nut. The perfor.mance of the valve shall be satisfactory when the hand lifting gear is use
32、d. The hand lifting gear is used within 100 lb/in2 of operating pressure. 3.3.4 The nominal size of a safety valve shall be the initial inside diameter of the inlet opening to the valve. The sizes and approximate capacities of the valve shall be as specified (see 6.2.1). Ordinarily, Valves will be o
33、rdered on the basis shown in table I. 60,000 maximuml/ 55,000 maximum, 1/ 30,000 maximum 20, 000 maximumf/ TABLE I. Nominal sizes. I Required capacity -1 Capacity tolerances 1 Nominal size -0, +5,000 -0, +5,000 -0, +5,000 -O, +2,500 2-1 /2 2-1 /2 1-1 /2 1-1 /2 f/68,500 pounds per hour (lb/h) for typ
34、e I and type III valves, and 24,000 lb/h for type II valves permitted on boilers having a total steam capacity in excess of 250,000 lb/h at full power. 3.3.5 Design pressure. Unless otherwise specified (see 6.2.11, safety valves shall be furnished in one of the standard design pressures specified in
35、 3.3.5.1 or 3.3.5.2. 3.3.5.1 600 lb/in2 standard. Valves for use on boilers having drum - - operating pressures up to 575 lb/in2 (for which the safety valve popping pressure may exceed 675 lb/in2, but will not exceed 750 lb/in2) shall be designed for a working pressure of at least 750 lb/in2 and in
36、the case of superheater valves, for an operating temperature of at least 875OF. - drum operating pressures of 676 lb/in2 to 1600 lb/in2 (for which the safety 3.3.5.2 1500 lb/in2 standard. Valves for use on boilers having - valve popping pressure may exceed 1600 lb/in2, but will not exceed 1700 lb/in
37、2) shall be designed for a working pressure of at least 1700 lb/in2. 1 3.3.6 Threaded parts. Threaded parts used in the construction of safety valves shall comply with FED-STD-H28 and as specified in 3.3.6.1 through 3.3.6.4. 3.3.6.1 Unified national thread standards. Unless otherwise specified (see
38、6.2.11, screw threads shall be in accordance with the unified national thread series. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-17YbZB YB 399790b 02723YO 7 h MIL-V-I7462B(SH) 3.3.6.2 Unifisd national coarse-thread series. Unless otherwi
39、se specified (see 6.2,1.), threads for studs and nuts shall be in accordance with the national coarse-thread series, class 2A or class 2B, as applicable. Set studs shall be chosen so as to best assure permanency of installation. 3.3.6.3 Pipe threads. Pipe threads shall be in accordance with FED-S TD
40、-H 2 8. 3.3.6.4 Thread projection. Bolt-studs and studs shall be sufficiently long to insure that, when nuts are screwed home, there shall be at least one-half thread projection clear from the outer face of the nut. The threaded portion on such bolts and ends of studs shall be not less than one and
41、one-half times the bolt or stud diameter. 3.3.7 Lock-ing device. The valve cap shall be locked with a padlock, 3.3.8 Welding and fabrication. Welding shall be in accordance with MIL-STD-278. Fabricated assemblies shall be stress relieved as units prior to finish machining. The stress relieving shall
42、 be done in accordance with MIL-STD-278. 3.3.9 Shock. When shock testing is required (see 6.2.1), the valve shall not be damaged or malfunction when tested as specified in 4.6.8. 3.4 Detai.1 design. 3.4.1 Relieving capacities. The relieving capacity of safety valves shall be as specified (see 6.2.1)
43、 and shall be based upon 103 percent of popping pressure. 3.4.1.1 The aggregate relieving capacity of the safety valves of each boi1,er shall be such that all of the steam generated at the overload condition will be discharged without allowing the drum pressure to increase more than 3 percent above
44、the highest pressure at which any valve is set, and in no case to increase more than 6 percent above the boiler design pressure. The relieving capacity of the superheater safety valve shall be such that the superheater will not be damaged by overheating or bursting should the firing rate be maintain
45、ed for 30 seconds at any firing rate from the specified minimum to maximum overload rate. .The capacity of the steam drum safety valves shall be not less than 75 perceyt of the steam generated at the overload condition. The relieving capacity of the drum pilot actuator valve shall be as small as pra
46、cticable consistent with proper degign and operation. 3.4.2 Safety valve settings. The popping pressures of safety valves shall be determined as follows: The steam drum pilot actuator valve shall be set to pop and open the superheater safety valve at a pressure of 8 Percent greater than the highest
47、working steam drum pressure (120 percent overload). The first, second, third, and fourth steam drum safety valves shall be set to pop at pressures of 2, 3.5, 5, and 5 percent, respectively, Of the highest working steam drum pressure higher than the pilot actuator valve setting. If the superheater sa
48、fety valve is of the spring loaded type, it shall be set at a pressure of 1.5 percent of the highest working 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-V-171-162B 98 9 7799706 027231-13 7 W MIL-V-174 62B (SH) steam drum pressure higher tha
49、n the pilot actuator valve setting. After calculating settings, round off to the nearest 5 lb/in2 gage pressure to specify set pressures. If the superheater safety valve and the pilot actuator have the same setting after rounding off, then specify the superheater safety valve setting to be 5 lb/in2 less than the pilot actuator setting. Prior to delivery, the popping and reseating pressures shall be set on all safety
