US 4,536,135 AGranted

High pressure liquid piston pump

AssigneeFlow Industries, Inc.

InventorsJohn H. Olsen, Sigurd C. Mordre

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Abstract

A piston and a cylinder within a pump housing cooperate with the inner walls of the housing to form a high-pressure reservoir surrounding the cylinder to provide a continuous compressive force thereon to prevent tensile stresses in the cylinder during pumping operations to prevent failure of the cylinder due to metal fatigue. A check valve between the cylinder and the reservoir permits high-pressure fluid to flow from the cylinder into the reservoir during pumping operations to maintain substantially the maximum cylinder pressure within the reservoir. The cylinder further includes therein an inlet with an associated check valve. Stationary seals in the pump use the high pressures in the cylinder and the reservoir for producing the sealing forces necessary to prevent leakage. The primary piston seal consists of a long, controlled clearance gap which permits a small leakage but has only minor contact and thereby low sliding stresses and a long life.

Claims13

Dependent claims

A pump, comprising:

a housing;
inlet means for admitting fluid into said housing;
fluid pressurizing means within said housing in communication with said inlet means for pressurizing fluid received therefrom;
said fluid pressurizing means having wall means with internal and external wall surfaces, wherein said fluid pressurizing means includes a cylinder within said housing defined by said wall means, said cylinder being in fluid communication with said inlet means;
a piston slidable within said cylinder for pressurizing fluid therein;
and means for actuating said piston to provide an intake stroke for admitting fluid into said cylinder and a pressure stroke for pressurizing fluid within said cylinder;
and wherein said means for controlling the pressure differential on said wall means includes reservoir means around the exterior surface thereof;
and means for providing fluid communication between the interior of said cylinder and said reservoir, whereby high-pressure fluid within said reservoir means provides a compressive force on said wall means to control the pressure differential thereacross as said piston moves between said intake stroke and said pressure stroke;
means for conducting a high-pressure fluid output from said housing and said fluid pressurizing means;
and,
means for controlling the fluid pressure differential acting on said wall surfaces, whereby stress on said wall means is controlled to prevent structural fatiguing thereof;
and,
a separator in a housing between said piston and said inlet for isolating said pumped fluid from a second fluid wherein the area between said separator housing and said cylinder is vented to said inlet to urge said separator housing toward said cylinder.

10 more elements

Dependencies are inferred from the claim text.