MIL-DTL-5523E
4.4.2.5 Extreme temperature performance. Extreme temperature tests shall be conducted on a valve (or valves)
assembled with parts to the most adverse tolerances conducive to binding at the temperature tested. Valves when
subjected to the normal temperature performance test shall meet the requirements of 3.5.4. The following details
shall apply:
4.4.2.5.1 Low temperature performance. A typical setup for this test is specified on figure 3. On the test valve
(minimum clearance specimen) apply pressure and flow to this valve with the hand pump at the rate of one full stroke
per minute. Note the highest pressure which can be developed at room temperature. The temperature of the cold
chamber shall be reduced to -65°F + 2°F (-53.9° + 1.1°C) and held for a minimum of 3 hours with the valve
unpressurized. The valve shall then be pressurized to approximately 90 percent of the minimum allowable reseat
pressure specified in table II and held for a minimum of 3 additional hours. The above hand pump test and the tests
outlined under 4.4.2.4.4 shall be repeated. Leakage and pressure valves obtained at -65°F (-53.9°C) shall not vary
more than +10 percent of -5 percent from those obtained during room temperature tests.
4.4.2.5.2 High temperature performance. Using the test temperature setup specified on figure 2, the minimum
clearance valve specimen shall be adjusted to deliver rated flow at a differential pressure equivalent to the maximum
pressure setting specified in table II. The valve and hydraulic fluid of the test setup shall be stabilized at test
temperature for a minimum period of 6 hours. The power driven pump tests outlined under 4.4.2.4.2 shall be
repeated. Leakage and rated flow shall not be greater than those observed at room temperature, and reseat
pressure shall meet the pressure valve specified in table II. Test temperature shall be 160°F + 5°F (71.1°C +2.8°C)
for type I system valves.
FIGURE 1. Typical relief valve endurance test installation.
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