MIL-DTL-87255A(USAF)
4.5.3 Outlet pressure regulation.
A tank shall be connected as specified in 4.4.4 during this test. A source of pressurized gas
shall be connected to the valve inlet port. The inlet gas pressure shall be increased and
maintained at 30 psig while equivalent acceleration forces of 2, 4, 6, 8, 9, 10, 9, 8, 6, 4, 2, and 1
Gz shall be applied in this order to the valve. Each force shall be maintained for at least 10
seconds before the next force shall be applied. The inlet pressure shall be increased to 70, 150
and 300 psig, and the test repeated at each of these inlet pressures. The outlet pressure shall
be as specified in 3.5.2.
4.5.4 Leakage.
With a force of 1 Gz applied to the valve, the inlet flow to the valve at an inlet pressure of 30, 70,
150, and 300 psig shall not exceed that specified in 3.5.3
4.5.5 Anti-chatter.
A tank shall be connected as specified in 4.4.4 during this test. A source of pressurized gas
shall be connected to the valve inlet connection. The inlet pressure shall be increased and
maintained at 30, 70, 150 and 300 psig. At each pressure level the valve shall be fully opened
manually, by pressing the press-to-test button, and held open to determine that there is no
evidence of chatter when there is air flow through the relief valve. Additional anti-chatter testing
shall be as detailed in 4.5.12.2.5.
4.5.6 Response time.
A tank shall be connected as specified in 4.4.4 during this test. A source of pressurized gas
shall be connected to the valve inlet connection and the pressure increased to and maintained
at 70 psig. A pressure transducer shall be connected to the tank to allow tank pressure to be
recorded as a function of time. Acceleration forces of 6, 1, 10 and 1 Gz shall be applied in this
order as a step input to the valve. Each force shall be maintained for at least 10 seconds before
the next force shall be applied. Tank pressure shall be recorded as a function of time for at
least 5 seconds following the application of each force level. The time interval from the time of
application of each force level to the time at which the tank pressure reaches the value specified
4.5.7 High temperature exposure.
The pressure regulating valve shall be conditioned at a temperature of 250 ±5 °F for eight
hours. After this period, the valve shall be immediately subjected to and pass the tests specified
1.25 and 2.0 Gz.
4.5.8 Low temperature exposure.
The pressure regulating valve shall be stabilized at a temperature of -65 ±5 °F. After this
period, the valve shall be warmed to -40 ±5 °F and immediately subjected to and pass the tests
between 1.25 and 2.0 Gz.
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