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|  MIL-V-19067A(ASG)
Qualification test methods.-
4.4
4.4.1 Examination of product - Qualification .- The maximum and minimum clearance
specimens shall each be carefully examined to determine the conformance with all the require-
ments of this specification and for any visible defects. The critical clearance dimensions
shall be checked and recorded for comparison of results.
4.4.2 Fluid immersion - All valves shall be immersed continuously in hydraulic
fluid for a period of 72 hours at a fluid temperature of 275F, prior to conducting the
remainder of the Qualification tests specified herein. All internal parts Or the valve
shall be in contact with the fluid during this immersion. After the 72-hour soak period,
the valve shall remain in the fluid at normal room temperature until ready for test. It
shall not be exposed to air internally for any appreciable length of time during the test.
4.4.3 Proof pressure - Qualification - This test shall be performed at a temperature
of 275F. A proof pressure of 4,500 psi shall be applied in both the free- and reverse-
flow directions at least two successive times in each direction and held for 2 minutes for
each pressure application. For the reverse-flow direction, the poppet shall be unseated
between applications of the proof pressure. There shall be no measurable external
leakage, failure, or permanent set.
4.4.4 Surge flow - This test shall be performed within a temperature range of
70 to 120F. A test setup similar to figure 1 shall be used,and the precharge pressure
for the accumulator shall be stabilized at 1,000 psi. The hydraulic test pressure shall
be 3,000 psi.The directional control valve shall be operated in the following sequence
for 25 complete cycles. The following four-point sequence Shall total one complete cycle:
(a)
The directional control valve handle shall be in a neutral
position to permit the buildup of rated hydraulic pressure in
the accumulator.
(b)
The directional control valve handle shall be quickly actuated to
permit flow through the controllable check valve in the free-flow
direction. The directional control valve handle shall be permitted
to remain in this position until the hydraulic pressure drops to not
more than the specified precharge in the accumulator.
The valve handle shall be returned to the neutral position to permit
(c)
the buildup of the required rated hydraulic pressure.
The directional control valve handle shall be quickly actuated to
(d)
permit reverse flow to the controllable check valve. The valve handle
shall be allowed to remain in this position for at least 3 seconds and
then moved to the original neutral position.
4.4.5 Qualification test for leakage - This test shall be perfomed with the
valve in the horizontal position. Unless otherwise specified, this test shall be
conducted at a fluid temperature of 100F. The valve shall be tested for internal leakage
by applying the pressures listed in table III for a minimum period of 32 minutes each.
The pressures shall be applied in the direction of reverse flow,and the valve poppet shall
be unseated between pressure applications. The leakage measurement period shall be
least 30 minutes in duration and shall begin 2 minutes after application of the required
pressure. The internal leakage shall not exceed the amount stated in table III. There
shall be no measurable external leakage during this test. This leakage test shall then
be repeated with the pressures applied in the direction of free flow with the other port
plugged.
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