Patent ID: 7874809
Filing Date: 2011-01-25
Classification: F04D

Abstract:
1. A water-lifting pump apparatus comprising: a suction tank; a discharge tank; a pump for pumping water in said suction tank into said discharge tank, and a discharge piping connected to a discharge side of said pump; actuating means for driving said pump said actuating means being capable of varying a rotational speed of said pump; a reverse flow prevention device for preventing a reverse flow of water pumped into said discharge tank toward said discharge piping; a detector for detecting a pressure or a flow rate of water in said discharge piping or a water level difference between a water level in said discharge tank or said discharge piping and a water level in said suction tank; and a control device for controlling said actuating means to control the rotational speed of said pump, wherein after an end of water pumping operation, said control device controls said pump to maintain rotation at a reduced rotational speed, said reduced rotational speed being based on a detected value of said detector and to allow for water in said discharge piping to fall into said suction tank through said pump.