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|  MIL-V-29592(AS)
4.7.7.2 High temperature performance. (Class I-only). With the test
apparatus of Figure 1 in an environmental chamber, the automatic air vent
valve and test fluid shall be hot soaked for 24 hours at 130F. With the
valve at 130F, the test procedures of 4.7.4.1 and 4.7.4.2 shall be repeated.
The valve shall continue to vent air during the opening and air venting test
and shall close during the closing and oil shut-off test. After closing there
shall be no oil expulsion.
4.7.8 Oil expulsion. (Class I only). Using the test apparatus on Figure
1 at a temperature of 650 to 95F, the air pressure shall be adjusted to the
minimum operating reservoir pressure as specified in the applicable military
specification sheet. The selector valve shall be opened and oil under
pressure ported to the air vent valve. After oil shut off, the automatic air
valve shall then be vented to the atmosphere using the selector valve and the
vent valve. This procedure shall be repeated for 100 pressure actuation
cycles and the oil expelled from the air outlet collected in the beaker. The
cycle rate shall not exceed 5 cycles per minute and the maximum rate of
pressure rise shall not exceed 30 psi per second. The average expulsion rate
per cycle, as specified in the applicable military specification sheet, shall
not be exceeded.
4.7.9 Endurance. The procedure for the oil expulsion test (4.7.8) shall
be repeated for a total of 50,000 cycles at room temperature. The cycle rate
shall be between 10 and 20 cycles per minute except for the last 100 cycles.
For the last 100 cycles the cycle rate shall be 5 cycles per minute or less
and the rate of pressure rise at 30 psi per second or less at room temper-
ature. The expulsion rate for the final 100 cycles shall be determined and
shall not exceed the value specified in the applicable military specification
sheet. The functional tests of 4.7.4 shall be repeated without failure,
premature air shut off, or excessive oil expulsion.
4.7.10 Pressure surge. The test valve shall be pressure surge tested in
accordance with ARP 1383 with the valve mounted in a test apparatus and the
outlet port plugged. The automatic air vent valve shall be subjected to
50,000 pressure surge cycles, at an environmental and fluid temperature as
specified in Table II. The maximum peak pressure shall be 150 percent of the
maximum reservoir operating pressure as specified on the applicable military
specification sheet. Cycling shall be performed at a rate of 300 cycles per
minute (cpm) maximum. There shall be no evidence of external leakage or
structural failure during the performance of this test. The actual pressure
surge pattern shall be recorded.
4.7.11 Vibration. The automatic air vent valve shall be vibration tested
in accordance with MIL-STD-81O. All tests shall be performed along two axes,
the axis parallel to the direction of flow and the axis perpendicular to the
direction of flow. Both sinusoidal and broad band random tests are required.
The automatic air vent valve shall be pressurized with oil at the minimum
reservoir pressure specified on the applicable military specification sheet
and shall be mounted on a resonant-free test fixture similar to Figure 2. The
input and output accelerometers shall both be mounted on the fixture with the
latter as close as possible to the test valve. Tolerances of the vibration
characteristics shall be:
10%
Amplitude
Frequency
2%
10%
Acceleration
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