Regenerative pump and casing thereof

摘要

A regenerative pump includes a casing which a recessed fluid flow passage interconnecting a suction port and a discharge port is formed in an arcuate shape. An impeller is provided rotatably with respect to the casing and formed with a plurality of vane members which face the recessed fluid flow passage. A recessed damping portion is formed in a terminal end portion of the recessed fluid flow passage on a discharge port side thereof to begin at a position corresponding to the discharge port and extend along a rotating direction of the impeller. The recessed damping portion has a depth which is smaller than that of a main depth of the recessed fluid flow passage and substantially constant.