trap valve

A test and pressure relief valve should be installed to assure relief of internal pressure prior to servicing and as a visual indication of trap operation.

A check valve should be installed on return piping if there will be a pressurized return line or the trap drains to an overhead return line (Fig. B).

The flat bottom gate provides full perimeter seating against the seat, eliminating pocket in the bottom of the seat that can trap process media and prevent the valve from fully closing.