LIQUID FLOW CONTROLLER HAVING PRESSURE BALANCED PISTON FOR DELIVERING CONSTANT FLOW

摘要

LIQUID FLOW CONTROLLER HAVING PRESSURE BALANCED PISTON FOR DELIVERING CONSTANT FLOW A small, lightweight, simple, and highly reliable flow controller (2) utilizing two moving parts (6, 48), for apportioning inlet fluid flow between an orifice outlet (26, 16) and inlet. Constant outlet flow over a substantial inlet flow and pressure range is achieved through the use of a flow balanced flow control piston (6) reciprocating internally of a housing (4). The balanced piston is biased to a predetermined proportioning range through an internal spring (48). The unit is normally operated with inlet port and outlet pressure sensing port in fluid communication with an external orifice (24). A bypass port (14) communicating with the controller inlet adjacent the control piston returns excess fluid to the reservoir (22) of a pumped fluid system. Increases in inlet flow to the regulator/orifice combination act to adjust the balanced piston position and initiate or increase flow across an integral piston/seat control orifice. The downstream or outlet pressure of the external orifice is sensed by an equal piston area distal the cylinder seat and/or inlet side of the piston. A damping piston (50) abuts said inlet pressure sensing portion of the piston in order to minimize transient piston motion or chatter.