C801T-500 Carbon Steel Manhole Cover Manhole Cover C801T-500 Carbon Steel Manhole CoverManhole Cover1.With Breathe Valve and Emergency vent device builtin, It can control the  interior and outerior pressure automaticaly to reach balance. While the tank  leaning,the valve will close itself to avoid the leakage effectively.2.When the temprature is too high and the pressure is beyond 2130kpa, the  emergency vent device will open to release the inside pressure of the tank  to avoid the explosion effectively.

C801T-500 Carbon Steel Manhole Cover