MIL-DTL-5516D
4.5.4.2.1 Leakage at low temperature. The same apparatus and packing rings used in previous
tests shall be charged to 1,500 psi (10.34 Mpa) at room temperature, the accumulator pressure
isolated from the test cylinder by closing the valves between the cylinder and accumulator and
the cylinder pressure allowed to fall to 5 to 10 psi (.034 to .069 Mpa). Temperature shall be
lowered to the range of -54° to -57°C. (-65° to -70°F) within 1 hour and held for at least 72 hours.
The following cycling and static operations shall then be performed in the order specified, using
fluid no warmer than -54°C (-65°F):
(a) Low-pressure cycling. At the end of this time, the piston shall be cycled at no-load pressure
for at least 10 cycles by opening the proper valves between the cylinder and reservoir and
bleeding sufficient pressure from the accumulator to move the piston at the minimum pressure
not to exceed 50 psi (.345 Mpa). The pressure shall be recorded. (The pressure in the cylinder
shall not be permitted to exceed 50 psi (.345 Mpa) at any time during these 10 cycles, as by
bottoming the piston, etc.).
(b) High-pressure cycling. The piston shall be cycled under high-pressure operation for at least
10 cycles by opening the proper valves between the cylinder and accumulator and bleeding
pressure from the opposite end of the cylinder to the reservoir. Minimum cycling pressure
permitted during this test is 1,500 psi (10.34 Mpa).
(c) High-pressure static. With the valves closed between the cylinder and the reservoir, the
valves between accumulator and cylinder shall be opened to allow a static pressure of 1,500 psi
(10.34 Mpa) minimum to both sides of piston without causing motion. The apparatus shall be
allowed to set for 1 hour. Pressure shall then be reduced to zero psi and the apparatus allowed
to warm up to room temperature over an 18-hour period.
NOTE: At the start of (a), (b), and (c), the piston rod shall be forcefully moved from side to side in
each of two planes, 90° apart.
Leakage during this entire test shall not exceed 20 drops (approximately 1.0 cc) per gland.
Leakage for V-rings during the entire test shall not exceed 10 cc per gland. There shall be no
evidence of wear, permanent set, or extrusion of the seals, or corrosion, sticking, or bad
discoloration of the adapters or metals adjacent to the packings after or during the entire
performance tests. The leakage shall be recorded.
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