The present invention discloses an adjusting apparatus for improving an anti-cavitation effect of a water pump. The adjusting apparatus comprises a centrifugal impeller (10), a volute (20), an adjusting device (30), a jet device (40), a pressure and/or flow monitoring device, and a controller. The centrifugal impeller comprises a rear side labyrinth seal (15) and a front side labyrinth seal (16), and the volute comprises a first sealing portion (21), a first pressure adjusting cavity (22), a second sealing portion (23) and a second pressure adjusting cavity (24), where the position of the first sealing portion is provided with the first pressure adjusting cavity, the position of the second sealing portion is provided with the second pressure adjusting cavity, the second pressure adjusting cavity is in communication with the first pressure adjusting cavity through the first pipeline.

Turbine pump assemblies and methods of making the same are provided. The assemblies include a body, a centrifugal pump having a shroud located within the body, a shroud cavity formed external to the shroud, and an ejector pump fluidly connected to the shroud cavity by a purge gas flow path, the ejector pump configured to reduce a pressure within the shroud cavity.

An ejector includes: a decompression chamber in an outer pipe on an air entrance side; a throat in the outer pipe on an air exit side; a nozzle in the outer pipe on the air entrance side, the nozzle having a leading end portion placed in a decompression chamber to inject air; and a suction port in the decompression chamber to suck blow-by gas into the decompression chamber. The air injected from the nozzle generates negative pressure in the decompression chamber to suck in blow-by gas through the suction port, and the sucked gas is discharged together with air through a throat. The valve in the nozzle includes a valve seat, a valve element, and a spring to press the valve element in a direction to separate from the valve seat. The valve element is formed with a bottom-closed cavity opening toward an upstream side of an air flow.