The Cla-Val Model 750-01 Pressure Relief, Sustaining and Back Pressure Valve is a hydraulically operated pilot actuated automatic control valve. The main valve consists of only two parts, a stainless steel body and an elastomeric liner or control element.
The main valve opens when inlet pressure begins to exceed a preset pressure and will allow enough flow to maintain that inlet pressure. In pressure sustaining service, Model 750-01 will conserve pressure in an upper system during periods of high demand in a system below. In pressure relief service, this valve will modulate to exhaust line pressure to keep it below a set point maximum. On a pump bypass system, the valve will allow flow back to the pump suction when pump discharge pressure exceeds the set point.
Cla-Val Model 750-01 will control from no flow to full open flow without any chattering or slamming under low flow conditions. For this reason, on by-pass, relief, and pressure sustaining service, there is never a region of control instability.