초록 ▼

A constant displacement pump and an associated flow control mechanism are disclosed. The flow control mechanism includes a variable orifice, i.e., a pintle and valve seat in the outlet from the pump. The pressure drop across the variable orifice controls the position of a bypass valve. The position

A constant displacement pump and an associated flow control mechanism are disclosed. The flow control mechanism includes a variable orifice, i.e., a pintle and valve seat in the outlet from the pump. The pressure drop across the variable orifice controls the position of a bypass valve. The position of the pintle member relative to the valve seat is controlled by fluid pressure acting on one end of the pintle member. The fluid pressure acting on the one end of the pintle member may be infinitely varied so that the position of the pintle member with respect to the valve seat may be infinitely varied. Fluid pressure acting on the one end of the pintle member is controlled by an electrical solenoid which infinitely positions a pilot member relative to a fluid pressure passage joining the opposite ends of the pintle member.

대표청구항 ▼

Apparatus comprising a pump for pumping fluid from an inlet to an outlet, means defining a variable orifice in said outlet for regulating fluid flow through said outlet, a fluid bypass valve adjacent to said variable orifice being directly responsive to the pressure drop across said orifice for bypa

Apparatus comprising a pump for pumping fluid from an inlet to an outlet, means defining a variable orifice in said outlet for regulating fluid flow through said outlet, a fluid bypass valve adjacent to said variable orifice being directly responsive to the pressure drop across said orifice for bypassing selected amounts of fluid from a point upstream of said variable orifice to said inlet so as to cause the pressure drop across said orifice to remain substantially constant as the size of said orifice is varied and if the pressure upstream of the orifice varies, said means defining said variable orifice including a valve seat and a pintle member movable relative to said valve seat between different positions in which said pintle member is spaced from said valve seat to thereby control the size of the orifice, said pintle member having first and second ends, said first end of said pintle member being located proximate said valve seat and being effective to restrict fluid flow through said valve seat to an extent which is dependent upon the position of said pintle member, said pintle member being positioned by the application of a pressure differential acting on said first and second ends thereof, means defining a pressure chamber adjacent to and in fluid communication with said second end of said pintle member, means defining a passage for supplying said chamber with fluid, means defining a fluid discharge passage for directing fluid from said chamber to said first end of said pintle member, a pilot member movable relative to said fluid discharge passage for controllably restricting the rate at which fluid flows from said chamber and thereby controlling the pressure differential across said pintle member and thus the position of said pintle member, and an electrical solenoid operable to position said pilot member in response to an electrical signal applied thereto, whereby variation of the amplitude of said electrical signal results in a corresponding variation in the fluid flow through said outlet.