1、MIL-V-8813(ASG) 20 NOVEMBER 1957 KLITARY SPECIFICATION VALVES: AIRCRAFT, HlDRAULIC PRESSURE RELIEF, TYPE II SpS!EPLS This specification has been approved by the Department of the Air Force am by the Navy mau of Aeronautics. 1. SCOPE inmen* 1.1 Sc .- his specification covers hydraulic prassure relief
2、 valves for use raft hydraulic systems conformFng to, Ud defined by Specification WIL-H-W. 1.2 Class5fication.- Hydraulic pressure relief valves shall be furnished in the sises rad for the rated daws indicated on the applicable HS standard for the class of service aa indicated in table I. TABLE I Cl
3、asses and rated flow pressures Staadard B28893 f Class y A B C D I Maximum pressure Rated flow pressure setting (psi) z/ differential between full flow and reseat pressure (psi) min max 500 L60 2,300 I 3,850 160 825 1,kOo 100 825 1,bO 2,300 270 i I - 1/ A .valve shall be adjustable to deliver rated
4、flow at any pressure within the range of the maximum and minimum rated flou pressure settings listed for ita class in table 1. Relief valves adjustable to the range of mre than one class shall carry in the part mnber the abbreviated letter designation of the lowest and highest pressure class and sha
5、ll conform to the appucable envelope, for example: A valve adjustable from 1,bOO to 3,850 psi uould be Part No. MS28893 CD. g/ .The rated flar pmssure setting is the pressure differential which results between the inlet and relief ports of the valve at rated flow. Provided by IHSNot for ResaleNo rep
6、roduction or networking permitted without license from IHS-,-,-2. APPLICABLE DOCDWENIS 2.1 The follaring specifications .ad standards, of the issue in efbmt on date of hdtation for bids, form a part of this mcification to the extent ttpcSi (a) lied to the pressure port at 8 rate of approximately 25,
7、000 psi per minute, and held or at least 2 minutes. Pressure shall then be similarly applied and maintained on the return port with the pressure port plugged. There shall be no measurable externdl leakage, failure, or permanent set. the back pressure from C to 200 psi at several fiovs between zero a
8、nd rated flow. The differential pressure shall at no time exceed the specified value in table I. The differential pressure at which rated flow occurs with 20G 225 psi back pressure shall be within 225 psi of the originzl differential pressure setting. 6 Provided by IHSNot for ResaleNo reproduction o
9、r networking permitted without license from IHS-,-,-HIL-V-8813 (ASG) r oSCSCoPE GA!3B SWL BE PLACE) AS CIDSE KI VALVE KELTS AS PRACTICABLE. FIGURE 1. Diagram for nonnal tenperature performance tests 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4
10、.6.4.2 Haximum setting.- The tests specified for “Minimum setting“ (4.6.4.1) shall be repeated uith the vdve adjusted to deliver rated flow at a differential pressure equivalent to the maximum pressure setting specified for its class in table I. 4.6.4.3 Reverse flaw leakage.- Uith.rated relief flow
11、pressure applied to the outlet port, leakage from the inlet port shall not exceed the values specified in table V during the third minute of a 3-minute uaifing period. 4.6.5 Nonaal temperature performance acceptance test).- 4.6.5.1 Pressure setting and reseat pressure.- Except where the contract or
12、order specifies the applicable setting pressure, each valve shall be set by means of a power- driven pump to deliver rated flow at a pressure setting equivalent to the maximum pressure duferential setting specified for its class in table I. The pressure shall then be reduced to the minimum allouable
13、 reseat pressure specified for its class in table I. Leakage at this pressure shall be observed in the third minute of a 3-minute waiting period, and shall not exceed the value shown in table IV. 4.6.5.2 Decreasing pressure leakage.- After checking the reseat pressure, the pressure shall be graduall
14、y decreased and leakage observed at pressure values of 3/b and 1/2 of the rated flow pressure setting. Leakage at these pressure values shall be observed in the third minute of a 3-minute uaiting period, and shall not exceed the values shm in table V. 4.6.5.3 Increasing pressure leakage.- After chec
15、king decreasing pressure leakage, the pressure shall be gradually increased and leakage observed at a pressure of 3/4 Of the rated flaw pressure setting and at the minimum allowable reseat pressure. Leakage observed, during the third minute of a 3-minute waiting period at 3/4 of the rated flow press
16、ure setting, shall not exceed the values shown in table V. Leakage similarly ob- served at the minimum reseat pressure shall not exceed the values shown in table IV. 4.6.6 Extreme temperature performance.- 4.6.6.1 Lou tempeIature performance:- With a test setup similar to figure 1, the valve shall b
17、e adjusted at room temperature to deliver rated flou at a differential pres- sure equivalent to the maximuIB pressure setting specified for its class in table I. The valve shall then be nstdLled in a test setup similar to figure 2. Cycling the hand pump at the rate of one full stroke per second, not
18、e the highest pressure uhich can be developed at mom temperature. The test setup su. then be maintained at a temperature of not uarmer than -65F for a period of 2 h0ui.s uith the.valve unpressurized, The valve 8hall.then be pressurized to appmxbately 90 percent of the minimum allowable reseat pressu
19、re spec5fied in table I, and held for a minimum of 2 additional hours. The hgm3 pump test outlined above shall then be repeated. The pressure value so obtained at -65.F shall not vary mre than -10 percent or -5 percent from that obtained during the room temperature test. 4.6.6.2 Ba id warnu The lm t
20、emperature arrangent shell tfien be alloued to uarm rapidly to M- a mpera re of 2750F. We the temperature is being raised ad without waiting for the temperature to stabilize throughout the setup, the hand pump shall be cycled as described above (4.6.6.1) at approximately %*F differentials in mient t
21、emperature. The pressure values 80 obtained at these temperalure increments shall not vary more than -10 percent or +S percent from those obtained during the room temperature test. 4.6.6.3 High temperature performance.- Unless otherwise indicated, this test sl-all be conducted at a temperature of 27
22、5wF, uith a test setup similar to fime 1, and uith the valve adjusted at room temperature to deliver rated flow at a differential pressure equivalent to the maximum ressure setting specified in table I. The test out- lined under Waximum setting“ (4.6.e.2) shall then be repeated at 275F and the requi
23、re- ments therein shall be satisfied. 8- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COLD CHAHBER I I ATMOSPBd 1 L SUPPLY OF FLUID (15 CU IN. DISCHARGE MIN) AT SAME TPlPERATURE AS FLU ID TEST VALVE AND SET-UP SUPPLY FIGURE 2. Typical schematlc di
24、agram for Lov temperature performce test 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-WItv-88I.3 (MG) 4.6.6.b Vibration.- The Vibration test, Pmcedure I, of Specification UIL-E-972 shall be conducbd except that the high temperature test shall -b
25、e conducted at 275.F in lieu of 140.F. Unless a positivt mechanical method of sscuring the $rasmm djusting device, .ecepbble to the procuring actirlty, is provided, the device shell be caupletely loosened and =tightened 15 times prior to conducting the vibration test. The valve shall then be adjuste
26、d to the appllcoble rated pressure flw setting. I)uring the vibration tests the valve shall be tested in accordance vith L.6.h and shall meet the requirements speci- fied therein. 4.6.7 Endurance cyclln .- The valve ahhall ba subjected to a total of 50,000 cycles uith a test setup sim& to figure 3.
27、The TTU ahall be adjusted at room temperature to deliver rated flou, as specified on the applicable drawings, at a dif- ferential pressure equivalent to the madmum pre08urc setting specified for its class in table I. Each cycle shall consist of mosing rated flou through the valre, and then reducing
28、pressure to substantially rem. Qcling shall be accomplished at the rate of 5 to 35 cpa. Of the total number of cycles, 12,500 shall be .perfonad in accordance vith the procedure outlined below for High temperature endurance cycling. The balance of 37,500 cfcles shall be performed in eccordaace vith
29、the procedure autllped below for Intermediate temperature durance cycling. 4.6.7.1 High temperature elldurance qlinn.- The valte shall be mbjected to 12,500 cycles .at a temperature of 275.F. Upon campletion of these 12,500 cycles, the Vdve shell be soked at a tsmperature of 275.F for a period of 1
30、hour with pressure equivalent to 90 percent of the reseat plesme applied to the valve. The pressure shall then be relieved to aproximately bero, and the valve sorked for an dditional period of 1 hour at a temperature of 275.F. The temperature of the test setup shall then be lowered to a range of 70.
31、F to 1XI.F and the fluid temperature stabuised at 100.F. Internal leakage shall then be meamred in the manner indicated herein for BXIBNHI setting at the previoudy recorded reseat pressure atxi at 1/2, and 3/& d the mexinum rated flow differential pressure setting. The leakage dues obtained hen shal
32、l be a maximum of .two times the corresponding values permitted during the original normal temperature performance mMaxinrum setting“ test (b.6.4.2). Follawing this, the Lou temperature performance test (h.6.6.1) rhdl then be repeated arrd the rsquirenent6 therein shall be satisfied. h.6.7.2 Interme
33、diate temperature endurance cycling.- The valve eha then be subjected to the balance of 37,500 cycles at a temperature of 225.F, internal leakage shall be mea-ured in the manner indicated herein for Vaximum setting“ (L.6.b.2) at the previously recorded reseat pressure and at 1/2, and 3/b of the rate
34、d flow diifer- ential pressure setting. The leakage values obtained here shaU be a maxjmum of two times the corresponding values permitted during the original nd tenperature performance “waximum setting“ test (h.6.b.2). The temperature of the test setup shall then be re- duced to a range of 70 to 12
35、0.F and the fluid temperature stabili%ed at 100F. The leakage shall then be shnilarly measured as outlined above for 225OF, and the leakage values so obtained here shall be a of two times the corresponding values mittad during the original nonaal temperature perfonoance W- setting“ teat of h.6.r2. s
36、eab, other Idwetted surface, which does not fonn a drop, nor ehall there be any other evidence of external leakage, durin(: perfonaance of the above teste. lr.6.8 External leak e.- There shell be no evidence of leakage through external h.6.9 Burst ressure.- This test shall be perfonned at a temperat
37、ure of 275.F. Any suitable *ed for this test. With all prta except the pressure port plugged, pressure shall be applied at a rate of approximately 25,oO3 psi per minute until a pressure of 7,500 psi ia obtained. ,The valve ahsll withstand this burst pressure for a period of. 2 minutes without ruptur
38、e of internal or external parts. 10 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1. L RESERVOIR SIISTM RELIEF VALVE. , SET FOR HIGHER PRGSSVRE THAN VUE UNDFB TEST. FIQJRIS 3. Typical relief valve Endurance test installation Provided by IHSNot for
39、ResaleNo reproduction or networking permitted without license from IHS-,-,-6. NO!ES 6.1 General.- The notes contained in section 6 of Specification -H-8775 form a part of tmcification. 6.1.1 Intended use.- Pressure relief valves covered by this specification are intended for use in type II, aircraft
40、 hydraulic systems, conforming to SpecFfication KL-H-SUO. The function of these rellef valves is to relieve pressure in excess of the applicable system or subsystem operating pressure. 6.2 Provisions for qualification.- With respect to products requiring qmlflication, auards will be made only for su
41、ch products as have, prior to the bid ope- date, been tested and approved for inclusion in the applicable Qualified Froducts List whether or not such products have actually been so listed by that date. 6.2.1 The attention of suppliers is called to this requirement, and manufacturers are urged to man
42、ge to have the products that they propose to offer to the Federal Government, tested for qualFfication in order that they may be eligible to be awarded contracts or orders for the products covered by this specification. Requests for infor- mation pertaining to qualification of products cwered by thi
43、s specification should be addressed to the Bureau of heronautics, Nwy Department, Washingten 25, D. C., the activity responsible for quaUfication, with a copy to the Commander, isright Ab Develop ment Center, WrightPattemon Air Force Base, Ohio. NOTICE: When Government drauings, specu.ications, or o
44、ther data are used for any purpose other than in connection with a definitely related Government procurement operation, the United States Government thereby incurs no responsibility nor any obligation whatsoever3 and the fact that the Govern- ment may have formulated, furnished, or in any way suppli
45、ed the said drauings, specifications, or other data is not to be regarded by implication or othervise as in any mamer licensing the holder or any other person or corporation, or conveying any rights or permission to mamLfactUre, use, or sell any patented invention that may in any way be related thereto. custodians: Navy - Bureau of Aeronautics Ab Force Preparing activity: Navy - Bureau of Aeronautics 12 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
