400W Emergency Pressure Relief Manhole Covers

The constant mixing of the biosolids in the digester could potentially create excessive foam build-up, which can clog digester cover equipment. The foam could clog the flame arresters installed with the Pressure and Vacuum Relief (PVR) Valves, especially without proper and routine maintenance. This leaves the PVR valves unable to perform its intended function of emergency pressure and vacuum relief. Without a secondary safety net, the tank is susceptible to explosion and implosion as pressure or vacuum rises in the tank.

  • 400w
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    • Hinged pivot design for automatic reseating after process conditions have returned to normal.
    • Pressure and vacuum relief (18" and larger sizes) available.
    • Minimum leakage rate.