摘要 |
<p>A hydraulic flow control valve is disclosed which is adapted for use as a pressure reducing valve, a flow control valve, or as a pressure relief valve. The valve includes a choke piston slidably mounted in a cylindrical bore for movement between a closed position closing communication between inlet and outlet channels, and an open position permitting such communication. An adjustable control system is provided for biasing the piston toward one of either its closed or open positions, and includes a constant volume flow restriction valve for providing a constant volume hydraulic flow. Downstream of the constant volume flow valve, there is provided a first branch line leading to an adjustable transducer for maintaining a selected pressure in the line, and a second parallel branch line leading to the bore in the housing for biasing the piston. Thus a selected pressure may be maintained in the second line, and thus also upon the piston, by adjustment of the transducer.</p> |