LIQUID PUMP AND LIQUID PUMP SYSTEM

摘要

PROBLEM TO BE SOLVED: To restrict a mechanical seal part from being damaged under a situation that when a plurality of pumps are connected in parallel and one or more pumps of them are used as a preparatory machine, a check valve provided at a secondary side of the pump is troubled and a partition valve provided at a primary side of the pump is closed and left as it is or water cannot be supplied to a suction side due to abnormal state of piping or other component parts.SOLUTION: A liquid pump comprises: a shaft rotatably supported; a casing for storing at least a part of the shaft and having a suction port; and a mechanical seal part provided at the suction port side in a direction where the shaft extends. The casing includes a pressure releasing passage from an adjoining space directly adjacent to the mechanical seal part to surrounding atmosphere.