Combination vacuum relief valve and pressure relief valve which are protected from the atmosphere

摘要

A vacuum relief valve assembly includes a vacuum valve member located below a top cover plate and is thus protected from the atmosphere. First passageways defined in part by a bottom cover plate provide communication between the outside atmosphere and the lower surface of the valve. Second passageways provide communication between the upper surface of the valve and the inside of the container. When the pressure in the container is below atmospheric, atmospheric pressure acting on the bottom of the valve lifts the valve and air flows through the first and second passageways until atmospheric pressure is reached in the tank. A pressure relief valve is mounted for pivotal movement relative to an opening providing communication between the pressure in the tank and the first passageways to vent pressure in the tank. The pressure relief valve is protected from the atmosphere by the top cover plate, and in one embodiment, by the vacuum relief valve.