Positive Displacement Pump Protection:

Positive displacement pumps are generally fitted along with relief valves on the upstream side of their discharge valves to protect the pump and its discharge piping from overpressurization. A Positive displacement pumps will discharge at the pressure needed through the system they are supplying. The relief valve avoids system and pump damage if the pump discharge valve is shut in during pump operation or if any other occurrence like as a clogged strainer blocks system flow.