PUMP

PROBLEM TO BE SOLVED: To prevent rise of manufacturing cost while enhancing pump efficiency. SOLUTION: A pump is equipped with a pump case which includes a pump chamber thereinside, openings of a suction port 9 and delivery port communicating to the pump chamber, and an impeller 13 freely rotatably arranged in the pump chamber. The impeller 13 consists of a substantially disc-like front shroud 13a having an opening of the suction port 13d at the center part, a substantially disc-like rear shroud 13b facing the front shroud 13a, a plurality of blades 13c disposed between both shrouds 13a, 13b and radially extended toward a radial outside from a radial center side, and a blow-off part 13e formed between outer peripheral ends of adjacent blades 13c. An annular groove 43 is provided in a front shroud counter surface 41 facing the front shroud 13a. COPYRIGHT: (C)2009,JPO&INPIT