3040 Back Pressure Relief Valves
The 3040 Series Back Pressure Valves relieve upstream pressure in a variety of processes. Automatically maintains desired maximum pressure in a vessel or system by relieving excess pressure into lower pressure return line or to atmosphere. Ideally suited for use as pump bypass control valve by maintaining constant pump discharge pressures. Used as a continuously operating valve or for intermittent protection against over-pressure conditions.
The 3040 Series Back Pressure Valve senses upstream pressure acting on the under side of the diaphragm through a port in the bottom diaphragm case. An in crease in the up stream pressure above the set point will compress the spring and allow the valve to open. The spring will close the valve as the upstream pressure decreases to the set-point.
The higher the system pressurizes above the relief set-point pressure, the more flow the valve will pass. It is therefore typical to specify the maximum capacity of a back pressure relief valve at 10% & 20% over set-pressure.
Pressure Adjustments :
Rotating the adjustment screw clockwise increases the compression on the spring, thereby in creasing the set-pressure. Rotating the adjustment screw counter-clockwise lowers the set-pres sure. Tighten the locknut after adjustment.
Catalog Specification Sheet
I&M