MIL-PRF-46720C
4.3.3.2.1 Pressure port.
4.3.3.2.1.1 Type I. The valve shall be subjected to hydraulic pressure at the pressure
port, with cylinder number 1 and 2 ports connected independently to loading valve and flow
meter, and the return port open. With 250 psi (1724 kPa) maintained at the pressure port, the
valve shall actuate with 18 Vdc or less applied to the solenoid. The pressure drop through the
valve, either energized or de-energized, shall be not more than 150 psi (1034 kPa) at 6 gal/min
(0.38 L/s) flow. With 3000 psi (20 685 kPa) maintained at the pressure port, the valve shall
actuate with application of 18 Vdc or less, and the pressure drop through the valve, either
energized or de-energized, shall be not more than 150 psi (1034 kPa) at 6 gal/min (0.38 L/s)
(see 3.3.2, 3.3.3 and 3.3.5.1).
4.3.3.2.1.2 Type II. The valve in the energized position shall be subjected to a hydraulic
pressure of 3000 psi (20 685 kPa) at port "A", and port "B" connected to a flow meter
(see 3.3.2). The valve shall then be energized, with an application of 18 Vdc, or less, actuating the
solenoid (see 3.3.3). With the valve de-energized and a flow through the valve of 3.5 gal/min
(0.22 L/s) , the pressure drop across the valve shall be recorded to determine conformance to
3.3.5. Test shall be repeated with set-up at port: "A" and "B" reversed.
4.3.3.2.2 Return port (type I only). The valve shall be energized with 18 Vdc, or less, at
a pressure differential of 250 psi (1724 kPa) between the pressure port and the return port
(pressure port at the greater procedure). A pressure of 1000 psi (6894 kPa) and a flow of
6 gal/min (0.38 L/s) shall then be applied at the return port. The pressure drop between the return
port and cylinder number 1 port shall be not more than 150 psi (1034 kPa), with a flow of
6 gal/min (0.38 L/s) in either direction. The test shall be repeated, except that 1000 psi
(6894 kPa) shall be applied at cylinder number 1 port (see 3.3.2, 3.3.3 and 3.3.5).
4.3.3.2.3 Actuation. With a hydraulic pressure of 3000 psi (20 680 kPa) at the pressure
port and the valve operating as in 4.3.3.2.1, the valve shall be actuated with 24 Vdc no less than
10 times to assure that there is no indication of binding, chatter, or other unsatisfactory operation.
4.3.3.3 Operating voltage and current. During testing, to determine conformance to
3.3.3, voltage shall be varied between 18 and 30 Vdc and operation observed. To determine
conformance to 3.3.4, current draw shall be measured during operation at 24 Vdc.
4.3.3.4 Rated flow and pressure drop. To determine conformance to 3.3.5, the rated flow
shall be accurately maintained at the value specified in 3.3.5. A manometer or other accurate
means of measuring pressure drop through interconnected ports shall be employed. The pressure
drop shall be measured and recorded.
4.3.3.5 Proof pressure. To determine conformance to 3.3.6, the valve shall be subjected
to the pressure specified in 3.3.6 at the pressure port and the return port (type I only) for a period
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