Regulator for regulating the output pressure of a motor driven pump

Claim 1

A regulator for regulating the output pressure of a pump which has a suction side and a pressure side and is operatively connected to a motor for driving the pump, said regulator comprising: a housing, means movably arranged in said housing and operatively connected to said motor for controlling said motor which is driving said pump in accordance with the amount of movement of said movable means in said housing, a passage in said housing located between a duct for connection to the pressure side of the pump and discharge opening to atmosphere, first and second valve means movably arranged in said passage for co-operation with each other and for sensing the output pressure from the pump, one of said first and second valve means being arranged in said passage to control the communication of said passage with the surrounding air so as to always allow at least a small quantity of fluid to flow from said duct via said discharge opening, a second passage extending from said duct to said movable means, whereby increased or decreased output from said pump brings about a displacement of said movable means to a maximum or minimum position in said housing, said movable means comprising two elements connected to each other, at least one chamber between said elements, at least one element being adapted to communicate with atmosphere, at least one of said elements being in pressure communication with a first chamber communicating with said at least one chamber, a middle chamber in said housing between said first chamber and said first and second valve means, a diaphragm separating said middle chamber, means for actuating said diaphragm, said actuating means including a shaft connnected to said diaphragm, and arm for actuating said shaft, and means for controlling the position of said arm.