The working principle of reciprocating pump

Working principle: piston moves upwards, form a negative pressure chamber in pump cylinder, the liquid flows into the pump by the suction valve. when the piston moving downwards, the suction valve closed, the liquid in chamber is forced to the discharge valve.

Before starting the reciprocating pump, the valves on pipeline(bothe of inlet and outlet) must be opened.

Piston pump

piston pump used for bilge water transferring sometimes, it also used for FO transfer on board ship. Piston pump is a displacement pump, it can do self priming, but it is not recommended to run the pump dry, making sure the delivery valve being opened before running.