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A variable flow pump includes: a housing with inlet and outlet chambers interconnected by a main bore and a non-rotating cylinder block positioned in the main bore. The cylinder block includes: a central bore communicating with the inlet chamber; cylinder bores arrayed around the central bore; first

A variable flow pump includes: a housing with inlet and outlet chambers interconnected by a main bore and a non-rotating cylinder block positioned in the main bore. The cylinder block includes: a central bore communicating with the inlet chamber; cylinder bores arrayed around the central bore; first feed passages interconnecting the inlet chamber and the cylinder bores, defining a bypass flowpath between the cylinder bores; and at least one discharge valve disposed at the second end which permits fluid flow from the cylinder bores to the discharge chamber but prevents opposite flow; Pistons are disposed in the bores. A shaft is coupled to the pistons so as to cause them to reciprocate through an axial pump stroke when the shaft is rotated. A mechanism is coupled to the cylinder block which modulates the axial position of the cylinder block within the housing, varying the size of the bypass flowpath.

대표청구항 ▼

What is claimed is: 1. A variable flow pump, comprising:(a) a housing including an inlet chamber and an outlet chamber interconnected by a main bore;(b) a non-rotating cylinder block with first and second ends disposed in the main bore, the cylinder block including:(i) a central bore disposed in flu

What is claimed is: 1. A variable flow pump, comprising:(a) a housing including an inlet chamber and an outlet chamber interconnected by a main bore;(b) a non-rotating cylinder block with first and second ends disposed in the main bore, the cylinder block including:(i) a central bore disposed in fluid communication with the inlet chamber;(ii) a plurality of cylinder bores arrayed around the central bore;(iii) a plurality of first feed passages interconnecting the inlet chamber and the cylinder bores, the first feed passages defining a bypass flowpath between the cylinder bores and the inlet chamber; and(iv) at least one check valve directly connected to the second end which permits fluid flow from the cylinder bores to the discharge chamber but prevents flow in the opposite direction;(d) a plurality of pistons disposed in the bores;(e) a shaft mechanically coupled to the pistons so as to cause the pistons to reciprocate through an axial pump stroke between predetermined fill and discharge positions, when the shaft is rotated; and(f) a mechanism coupled to the cylinder block which is adapted to selectively axially position the cylinder block within the housing, so as to vary the size of the bypass flowpath.