Model 8311HP and 8311 LP Back Pressure/ Relief Regulator

The Models 8311HP and 8311LP are high capacity, self-contained back pressure/relief regulators with a double-seat design. These units are utilized to control inlet (upstream) pressure between 1 and 200 psig (.07- 13.8 Barg). Available in two inlet pressure designs; LP - larger diaphragm design for relief pressures up to 30 psig (2.1 Barg), and HP - smaller diaphragm design for reliefpressures up to 200 psig (13.8 Barg).


Designed for controlling a wide range of fluids including air, inert gases, chemicals, water, fuel oils and steam.

  • High Capacity: The highest capacity back pressure regulators Cashco manufactures due to dual ports.
  • High Stability: Outstanding operation resulting from balanced design which maximizes opposing plug forces, even at very low pressure drops. Diaphragm isolated from fluid velocity effects.
  • Heavy Guiding: Plug is top and bottom guided with hardened stem guides.