Hydraulic pump with foamed elastomeric member in outlet chamber to reduce liquid-borne noise
AssigneeIMO Industries, Inc.
InventorJohn DiRe
Life of this patent
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Abstract
A noise-absorbing medium is provided as an insert within the inner volume of the outlet chamber of a displacement-type pump. In an axial-flow displacement pump, this is the chamber into which pumped hydraulic fluid is discharged, for side-ported delivery to piping which serves the end-use actuator or other use component of the involved hydraulic system. The noise-absorbing medium is a preformed body (or bodies) of foamed elastomeric material having a sealed external skin and containing tiny closed cells of entrapped gas at low pressure; the encapsulated gas within the body bears a predetermined fractional volumetric proportion to the overall volume of the body, and the overall volume of the body also bears a predetermined relation to the overall volume of the outlet chamber.
Claims8
A displacement-type hydraulic pump, comprising a rotor-housing part having axially spaced inlet and outlet ends and a cover part secured to the outlet end of said rotor-housing part, an elongate rotor having a pumping portion within said rotor-housing part and a driven portion journalled for rotation in said cover part, said cover part coacting with the outlet end of said rotor-housing part to define an annular chamber surrounding a portion of said rotor for receiving pumped hydraulic fluid discharged at the outlet end of said rotor-housing part, said chamber having an outlet port for discharge of pumped hydraulic fluid from said chamber, and a body of foamed elastomeric material retained within said chamber at offset from said outlet port, said body of elastomeric material having a volume that is in the range of 0.1 to 0.3 of the volume of said chamber.
In a hydraulic pump wherein a driven mechanical element within a stationary housing is operative to displace hydraulic fluid from an inlet chamber to an outlet chamber having an outlet port, the improvement wherein a body of foamed elastomeric material is contained within said outlet chamber at offset from said outlet port, said body of elastomeric material having a volume that is in the range of 0.1 to 0.3 of the volume of said chamber.
Dependencies are inferred from the claim text.