Abstract: This invention relates to an improvement on a centrifugal pump including: a casing defining an inlet path extending at the axial portion thereof, a turbine chamber communicating with the inlet path, and an outlet path disposed at the outer periphery portion of the turbine chamber; a drive shaft rotatably held in the casing; and a turbine fixed on the drive shaft and disposed rotatably in the turbine chamber.

Abstract: A centrifugal pump of the vortex-flow type includes a pump housing defining therein an arcuate pump chamber in surrounding relationship with a central sealed chamber, and a disc-like impeller rotatably and axially movably assembled within the pump housing and having opposite end faces each forming a close clearance with a corresponding internal end wall of the pump housing between the sealed and pump chambers, the impeller having on either end face of the rim portion thereof a plurality of circumferentially equally spaced vane grooves which cooperate with the pump chamber to produce a discharge pressure therein and being formed with at least one pressure balancing hole extending axially therethrough in the interior of the sealed chamber.

Abstract: A check valve assembly of the quick shutoff type equipped with an auxiliary valve of the slow closure type, wherein the check valve assembly comprises a primary valve plate arranged within a valve housing to open and close a primary cylindrical bore in the valve housing, and a swingably pressure receiving plate secured at one end thereof to the primer valve plate to be applied with a hydraulic pressure, and wherein the auxiliary valve comprises a cylindrical valve casing mounted on a portion of the primary valve plate, the valve casing being formed with a secondary cylindrical bore and formed at the peripheral wall with a radial hole which is arranged at the down stream of the primary valve plate, a cup-shaped cylinder coupled with one end of the valve casing, a piston slidably disposed within the cylinder to form a chamber in the cylinder, flow restriction means arranged to provide a fluid communication between the chamber and the interior of the valve casing, a valve element slidably disposed within the val

Abstract: A check valve assembly of the quick shutoff type equipped with an auxiliary valve of the slow closure type, wherein the check valve assembly comprises a primary valve plate arranged within a valve housing to open and close a primary cylindrical bore in the valve housing, and a swingably pressure receiving plate secured at one end thereof to the primary valve plate to be applied with a hydraulic pressure, and wherein the auxiliary valve comprises a cylindrical valve casing mounted on a portion of the primary valve plate, the valve casing being formed with a secondary cylindrical bore and formed at the peripheral wall with a radial hole which is arranged at the down stream of the primary valve plate, a cup-shaped cylinder coupled with one end of the valve casing, a piston slidably disposed within the cylinder to form a chamber in the cylinder, flow restriction means arranged to provide a fluid communication between the chamber and the interior of the valve casing, a valve element slidably disposed within the va