Patent ID: 6695278
Filing Date: 2004-02-24
Classification: B22D,G05D

Abstract:
A proportional flow control valve for controlling the flow of a fluid through a flexible tube, comprising in combination:a. first and second jaws for engaging opposing sides of the flexible tube; b. an actuator coupled to at least one of said first and second jaws for varying a separation distance between said first and second jaws, said actuator being adapted to vary said separation distance between an initial separation distance and a shut-off separation distance, the initial separation distance being large enough to avoid significant restriction of the flow of fluid therethrough, the shut-off separation distance being just small enough to essentially block the flow of fluid therethrough; c. a control system for controlling said actuator to select the separation distance between said first and second jaws; and d. a plurality of springs and a selector, said selector selecting a number of said plurality of springs for being compressed when said actuator decreases the separation distance between said first and second jaws, the selected plurality of springs exerting a biasing force when compressed, the biasing force tending to increase the separation distance between said first and second jaws.