1、Beneficial comments (recommendations, additions, deletions) and any pertinent data that may be of use in improvingthis document should be addressed to: Oklahoma City Air Logistics Center/TICLA, 3001 Staff Drive, Suite 1AE1-101A, Tinker AFB, OK 73145-3036 by using the Standardization Document Improve
2、ment Proposal (DD Form 1426)appearing at the end of this document or by letter.AMSC N/A FSC 4820INCH-POUNDMIL-PRF-25675C26 NOVEMBER 1997SUPERSEDING(See 6.8)PERFORMANCE SPECIFICATIONVALVES, CHECK, MINIATURE, HYDRAULIC,AIRCRAFT AND MISSILEThis specification is approved for use by the Department of the
3、 Air Force and is available for use by allDepartments and Agencies of the Department of Defense.1. SCOPE1.1 Scope . This specification covers hydraulic, spring-loaded, normally closed aircraft and missile hydraulicsystem check valves with operating pressures up to 3,000 pounds per square inch (psi)
4、and operating temperaturesfrom -65 to 450 F.1.2 Classification . There are two styles of check valve, flared and flareless, with seven sizes of each styledesignated by part number suffixes -4, -5, -6, -8, -10, -12, and -16. The flared and flareless check valves are shown inFigures 1 and 2, respectiv
5、ely. The check valve required should be indentified in 6.2.2. APPLICABLE DOCUMENTS2.1 General . The documents listed in this section are cited in sections 3 and 4 of this specification. This sectiondoes not include documents cited in other sections of this specification or recommended for additional
6、 information oras examples. While every effort has been made to ensure the completeness of these lists, document users are cautionedthat they must meet the requirements specified in the documents cited in sections 3 and 4 of this specification, whetheror not they are listed.2.2 Government documents
7、.2.2.1 Specifications and standards . The following specifications and standards form a part of this document to theextent specified herein. Unless otherwise specified, the applicable issues of these documents are those listed in thespecific issue of the Department of Defense Index of Specifications
8、 and Standards (DoDISS) and supplement theretocited in the solicitation (see 6.2).SPECIFICATIONSDEPARTMENT OF DEFENSEMIL-H-5606 - Hydraulic Fluid, Petroleum Base; Aircraft, Missile And OrdnanceMIL-H-83282 - Hydraulic Fluid, Fire Resistant, Synthetic Hydrocarbon Base, Aircraft,Metric, NATO Code Numbe
9、r H-537Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25675C2STANDARDDEPARTMENT OF DEFENSEMS33514 - Fitting End, Standard Dimensions for Flareless Tube Connection and Gasket Seal(Unless otherwise indicated, copies of the above specifications
10、 and standards are available from the StandardizationDocument Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)2.3 Non -Government publications . The following document forms a part of this document to the extent specifiedherein. Unless otherwise specified, the applicable is
11、sues of the documents that have been adopted by the DoD arethose listed in the specific issue of the DoDISS cited in the solicitation. Unless otherwise specified, the documents notlisted in the DoDISS are the issues of the documents cited in the solicitation (see 6.2).SOCIETY OF AUTOMOTIVE ENGINEERS
12、 (SAE)SAE AS 4395 - Fitting Ends, Flared Tube Connection, Design Standard(Application for copies should be addressed to Society of Automotive Engineers, Inc., 400 Commonwealth Drive,Warrendale, PA 15096-0001.)2.4 Order of precedence . In the event of a conflict between the text of this document and
13、the references citedherein, except for related associated specifications or specification sheets, the text of this document takes precedence.Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has beenobtained. If there is a conflict between the
14、contents of this specification and an associated specification orspecification sheet, the associated specification or specification sheet will apply.3. REQUIREMENTS3.1 Qualification . The valve furnished under this specification shall be products that are authorized by thequalifying activity for lis
15、ting on the applicable qualified products list before contract award (see 4.2. and 6.3).3.2 Recycled, recovered, or environmentally preferable materials . Recycled, recovered, or environmentallypreferable materials should be used to the maximum extent possible provided that the materials meet or exc
16、eed theoperational and maintenance requirements, and promote economically advantageous life cycle cost.3.3 Materials . All materials shall not produce toxic or deleterious fumes and shall be resistant to corrosion due toelectrolytic decomposition, hydraulic fluids, salt fog, or any other conditions
17、that may be encountered duringoperational use or storage.3.4 Interface .3.4.1 Dimensions . The weight and dimensions of the valve shall conform to Figure 1 and Figure 2.3.4.2 Hydraulic fluid compatibility . The valve shall be compatible with hydraulic fluid conforming to MIL-H-5606and MIL-H-83282 in
18、 a hydraulic system (see 6.4).Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25675C33.4.3 Item identification . The valve shall be permanently and legibly marked with the following information:a. Manufacturers nameb. Manufacturers CAGE codec
19、. Manufacturers part number (PN)d. National Stock Number (NSN)e. Date of manufacture3.5 Environmental conditions . The valve shall operate under the following conditions:a. Temperature: 65 to 450 F.b. Vibration: (1) a frequency between 20 and 90 Hz with a 0.05 double amplitude.(2) a frequency betwee
20、n 90 and 2,000 Hz with an acceleration of 20g.3.6 Performance .3.6.1 Proof pressure . The valve shall withstand a proof pressure of 4,500 (+150, -0) psi at 450 5 F in both thefree-flow and reverse-flow directions.3.6.2 Surge flow . The valve components shall withstand 25 flow cycles (see 6.5.4).3.6.
21、3 Leakage . When the valve is held in the horizontal or vertical position, the internal leakage rate of the valveshall not exceed the values specified in Table I with the pressure applied in the reverse flow direction.TABLE I. LeakagePressure (psi) Maximum leakage rate(drops per minute)5 11,000 to 3
22、,000 None3.6.4 Checking time and cracking pressure . The checking time (see 6.5.1) of the valve shall not exceed 1.5seconds. The cracking pressure (see 6.5.2) shall be between 2 and 8 psi.3.6.5 Pressure drop . The pressure drop through the valve at rated flow shall not exceed 15 psi.3.6.6 Endurance
23、. The valve shall withstand 50,000 impulse cycles (see 6.5.5) at the rate of 30 to 100 cycles perminute (cpm) at a temperature of 450 10 F.3.6.7 Burst pressure . The valve shall withstand a maximum pressure of 7,500 psi.3.6.8 Flexural strength . The valve shall withstand flexing (see 6.5.3) at 450 1
24、0 F.3.6.9 Repeated assembly . The valve shall be capable of repeated assembly and disassembly without affecting theperformance or life of the valve.3.6.10 Workmanship . The valve shall be constructed in accordance with commonly accepted industrialworkmanship standards.Provided by IHSNot for ResaleNo
25、 reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25675C44. VERIFICATION4.1 Classification of inspections . The inspection requirements specified herein are classified as follows:a. Qualification (see 4.2).b. Conformance inspection (see 4.3).4.2 Qualification inspection . Qu
26、alification inspections shall be performed on two valves. One valve shall besubjected to tests indicated in 4.2.1 and the other valve to tests indicated in 4.2.2.4.2.1 Minimum dimension test sample . One test sample shall be assembled of parts whose dimensions are at theminimum of the tolerance rang
27、e. This test sample shall be subjected to the following tests in the following order:a. Examination of product (4.6.1).b. Leakage (4.6.4).c. Proof pressure (4.6.2).d. High temperature (4.6.11).e. Repeated assembly (4.6.16).f. Salt-fog (4.6.17).g. Final examination (4.6.18).4.2.2 Maximum dimension te
28、st sample . The second test sample shall be assembled of parts whose dimensions areat the maximum of the tolerance range. This test sample shall be subjected to the following tests in the followingorder:a. Examination of product (4.6.1).b. Proof pressure (4.6.2).c. Surge flow (4.6.3).d. Repeated ass
29、embly (4.6.16).e. Vertical leakage (4.6.5).f. Checking time (4.6.6).g. Cracking pressure (4.6.7).h. Pressure drop (4.6.8).i. Low temperature (4.6.9).j. Intermediate temperature (4.6.10).k. High temperature (4.6.11).l. Endurance (4.6.12).m. Vibration (4.6.14).n. Flexural strength (4.6.15).o. Burst pr
30、essure (4.6.13).p. Final examination (4.6.18).4.3 Conformance inspection . Each valve shall be subjected to the tests below:a. Examination of product (4.6.1).b. Proof pressure (4.6.2).c. Ve rtical leakage (4.6.5).d. Cracking pressure (4.6.7).e. Final examination (4.6.18).Provided by IHSNot for Resal
31、eNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25675C54.4 Inspection conditions .4.4.1 Test fluid . The test fluid used during testing shall conform to MIL-H-5606 or MIL-H-83282. The test fluidshall be filtered continuously through a 15-micron absolute filter.4.4.2 Tem
32、perature . Unless otherwise specified, the tests shall be performed at an ambient temperature of 70 to90 F and a test fluid temperature of 70 to 110 F.4.4.3 Valve axis position . Unless otherwise specified, tests may be made with the valve axis in either a horizontalor vertical position. For the ver
33、tical position the inlet port shall be positioned so that the force of gravity shall act withthe valve checking action (i.e., direction of flow is up).4.4.4 Immersion . Prior to performing any tests, except examination of product, the valve shall be immersed in450 5 F test fluid for 72 hours. All in
34、ternal parts shall be in contact with the fluid during this period. Afterimmersion, the valve shall remain in ambient temperature test fluid until ready for tests. The valve shall not beexposed to air for more than 24 hours between tests.4.5 Requirements cross-reference matrix . Table II provides a
35、cross-reference matrix of the section 3 requirementstested or verified in the paragraphs below.TABLE II. Requirements cross-reference matrixRequirement Verification3.1 4.23.3 4.6.1, 4.6.17, 4.6.183.4.1 4.6.13.4.2 4.6.1, 4.6.183.4.3 4.6.13.5 4.6.9, 4.6.10, 4.6.11, 4.6.143.6.1 4.6.23.6.2 4.6.33.6.3 4.
36、6.4, 4.6.53.6.4 4.6.6, 4.6.73.6.5 4.6.83.6.6 4.6.123.6.7 4.6.133.6.8 4.6.153.6.9 4.6.163.6.10 4.6.14.6 Tests .4.6.1 Examination of product . The valve shall be examined to determine compliance with materials, dimensions,markings, and weight.4.6.2 Proof pressure . After the valve has reached 450 5 F,
37、 the valve shall have flow applied in both the free-flow and reverse-flow directions at least 2 successive times in each direction. During each flow, a proof pressure of4,500 (+150, -0) psi shall be applied and held for 2 minutes. For the reverse-flow direction, the poppet shall beunseated between a
38、pplications of the proof pressure. There shall be no evidence of damage or deformation.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25675C64.6.3 Surge flow . The valve shall be disassembled and inspected for cracks, bulges, gouges, and oth
39、er deformationsand then reassembled. Pressure shall be applied to the valve and the valve pressure stabilized at 3,000 psi.Twenty-five flow cycles shall be applied to the valve. After completion of the 25 flow cycles, the valve again shall bedisassembled. Any evidence of damage or deformation is a c
40、ause for rejection.4.6.4 Leakage . The valve shall be held in both the horizontal and vertical positions and a reverse-flow pressureshall be applied to the valve for 30 minutes in each position. The leakage measurement period shall begin 2 minutesafter pressure is applied, and the internal leakage s
41、hall not exceed the amounts indicated in Table I. Any evidence ofexternal leakage throughout the pressure range, except a slight wetting at the seals insufficient to form a drop, is acause for rejection.4.6.5 Vertical leakage . The valve shall be held in the vertical position. Each pressure specifie
42、d in Table I shall beapplied in the reverse-flow direction for 5 minutes. The valve poppet shall be unseated between each pressureapplication. In each case, the leakage measurement period shall consist of the last 3 minutes of the 5-minute period.The rate of internal leakage shall not exceed the amo
43、unts specified in Table I. Any evidence of external leakagethroughout the pressure range, other than a slight wetting at the seals insufficient to form a drop, is a cause forrejection.4.6.6 Checking time . The valve shall be held in the vertical position and the valve poppet shall be mechanicallyact
44、uated to its full open position against a test fluid static head of 5 psi. The valve then shall be allowed to checkbefore the test fluid static head decreases to 1 psi. The checking time shall not exceed 1.5 seconds.4.6.7 Cracking pressure . Pressure shall be applied gradually at the valve inlet in
45、the free-flow direction beginningat 0 psi. Cracking pressure shall be between 2 and 8 psi.4.6.8 Pressure drop . The valve shall be installed at a distance of 4-tube diameters downstream from a piezometerpressure pickup and a distance of 15-tube diameters upstream from the return pressure pickup. Pre
46、ssure drop throughthe valve shall be measured at the rated flow. The temperature of the test fluid shall be maintained at 100 5 F. Thepressure drop through the valve shall not exceed 15 psi.4.6.9 Low temperature . The valve shall be connected to a test fluid static head of 1 to 3 feet in the reverse
47、-flowdirection. If the valve contains nonmetallic parts other than static seals, the valve shall be maintained at a temperaturenot warmer than -65 F for 72 hours. If all parts of the valve except static seals are metallic, this period shall bereduced to 24 hours. After this period, the poppet shall
48、be actuated mechanically at least twice. At the end of this test,the valve shall be subjected to tests specified in 4.6.5 through 4.6.8.4.6.10 Intermediate temperature . The valve shall be actuated by reverse-flow pressure at increments of 40 F todemonstrate that the valve operates satisfactorily ac
49、ross the test fluid temperature range of -65 F to 450 F.4.6.11 High temperature . With the temperature of the valve maintained at 450 10 F, a test fluid static head of 1to 3 feet on the valve, and the valve in the reverse-flow direction, the poppet shall be actuated mechanically at leasttwice. At the end of this test, the valve shall be subjected to tests specified in 4.6.5 through 4.6.8.4.6.12 Endurance . While maintaining tempera
