NORMALLY CLOSED PRESSURE COMPENSATED FLOW CONTROL VALVE

摘要

A normally closed pressure compensated flow control valve assembly for use with a hydraulic cylinder provides metering of fluid from the cylinder at a constant desired rate for lowering a load connected thereto at a corresponding constant rate. The valve assembly includes a first valve (12) communicating with the cylinder and is selectively actuable for permitting the flow of fluid from the cylinder. A pressure compensating valve (14) is in communication with the first valve (12) and maintains a constant fluid flow pressure and a constant fluid flow rate from the cylinder. A baffle (72) is in communication between the first valve (12) and the pressure compensating valve (14). The pressure compensating valve (14) is normally closed prior to the actuation of the first valve (12) and opens gradually in response to the fluid exiting the cylinder to gradually increase the flow rate to a desired level and to maintain the flow rate constant thereafter.