Wellmark Series 3535 Cemco-Style Back Pressure Valve

This valve can be used anywhere upstream pressure is required to stay within a preset range. It may also be used as a pressure relief valve, a custody-transfer dump valve to hold back certain pressure, or as a separator back pressure valve on the gas or liquid side. Upstream pressure is applied to the bottom of the diaphragm through connecting tubing. Spring tension above the diaphragm opposes this pressure; when the pressure exceeds the spring's pressure setting, the plug rises from the seat. By varying the spring tension, the pressure setting can be controlled. The typical application for these valves is to hold back pressure on separators, treaters, Lact units, etc.