MIL-PRF-25962F
4.5.8 Reliability. Four valves shall be tested for reliability. The valves shall be operated
under cryogenic conditions simulating actual usage. Reliability of the equipment shall be
expressed in terms of mean cycles between failures (MCBF) and shall be not less than 1,000
cycles. A cycle shall consist of operating the valve between the "OPEN" and "CLOSED"
position with liquid oxygen at a pressure of 300 psig applied to the inlet port of the valve. Liquid
must pass through the valve each cycle. Every 400 cycles, the valve shall be subjected to outlet
port leakage test (see 4.5.3) and the overall leakage test (see 4.5.7). The valves shall be cycled
until failure. Any evidence of leakage or malfunction shall constitute a failure.
4.5.9 Cleanliness. All surfaces shall be free of visible particulates (50 microns or larger),
free of visible fluorinated lubricants, and free of hydrocarbon contamination to a level not greater
than 3 mg/ft2. Cleanliness shall be demonstrated by subjecting the valves to the tests specified in
SAE-ARP1176 or industrially accepted test methods (see 6.5).
4.5.10 Orientation. While the valve is in three mutually perpendicular positions, it shall
be subjected to the outlet port leakage test (see 4.5.3) and the vibration test (see 4.5.6).
4.5.11 Corrosion. A corrosion test or materials certification shall be used to demonstrate
satisfactory compliance with requirement 3.3.
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as
specified in the contract or order (see 6.2). When packaging of materiel is to be performed by
DoD or in-house contractor personnel, these personnel need to contact the responsible packaging
activity to ascertain packaging requirements. Packaging requirements are maintained by the
Inventory Control Point's packaging activities within the Military Service or Defense Agency, or
within the military service's system commands. Packaging data retrieval is available from the
managing Military Department's or Defense Agency's automated packaging files, CD-ROM
products, or by contacting the responsible packaging activity.
6. NOTES
(This section contains information of a general or explanatory nature that may be helpful, but is
not mandatory.)
6.1 Intended use. The valve covered by this specification is intended to be used to drain
70 and 300 psig liquid oxygen converters.
6.2 Acquisition requirements. Acquisition documents should specify the following:
a.
Title, number, and date of this specification.
b.
Item identification.
c.
Reliability (see 3.5.8).
d.
If qualification data is required (see 4.2).
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