QDV is a shut-off valve, designed particularly for draining oil from systems containing refrigerant (ammonia) under pressure.The valve will close immediately on release of the handle, thus protecting user and environment against unnecessary refrigerant leaks.In order to prevent hydraulic pressure building up between the stop valve and the QDV an integral relief device is included as part of the cone arrangement, which will open at approx. 16 bar (232 psig).QDV is designed to meet the safety demands specified by national and international authorities within industrial refrigeration.