SUBMERSIBLE MOTOR PUMP, MOTOR PUMP, AND TANDEM MECHANICAL SEAL

摘要

A submersible motor pump includes a water jacket (11) having a circulation passage (24A, 24B, 24C, and 24D) of a coolant, a centrifugal impeller (20) for circulating the coolant, a suction passage configured to provide fluid communication between the circulation passage (24A, 24B, 24C, and 24D) and a fluid inlet of the centrifugal impeller (20), and a discharge passage configured to provide fluid communication between a fluid outlet of the centrifugal impeller (20) and the circulation passage (24A, 24B, 24C, and 24D). The discharge passage includes a heat-exchange passage (80) formed by two wall surfaces, one of which is constituted by a member which contacts a liquid conveyed by a main impeller (12). The heat-exchange passage (80) has a circular shape extending radially outwardly from the fluid outlet of the centrifugal impeller (20). The heat-exchange passage (80) includes at least one axial passage section having a length component in an axial direction of the rotational shaft (1).