Pressure protection valve (also called a priority valve) used on M35A3 and some M939 series. Also for use with the air assist steering system installed on some M35A2. P/N KN-31000, 12450226, RCSK15078. NSN 4820014085662. Closing pressure of 45 PSI. Opening pressure is 65 PSI. 1/4 inch pipe thread supply port and 1/4 inch pipe thread outlet port, plus one 1/8 inch pipe thread aux port. Includes plugs for unused ports.
For an alternate style of protection valve see p/n 11669104.
Pressure protection valve details:
Air entering the supply port is blocked from flowing out the delivery port by the inlet valve, which is normally held closed by the pressure regulating spring above the piston. When sufficient air pressure builds beneath the piston, the piston will move, opening the inlet valve and allowing air to flow out the delivery port. As long as air pressure at the supply port remains above the specified closing pressure, the inlet valve will remain open. If a low air pressure condition develops, the valve closes effectively isolating unnecessary devices and reserving remaining air for vehicle braking.