Fluid control system

Abstract

A fluid control system 10 for a pilot-operated pressure regulating valve comprises a first conduit, defining a first flow path, and a second conduit 14, defining a second flow path. The second conduit 14 is parallel to the first conduit and comprises a restriction aperture 70. A variable flow restrictor 20 within the second conduit 14 is arranged to selectively vary a cross-sectional area of the restriction aperture 70. The first conduit comprises a converging portion 48, for reducing the pressure of fluid flowing through the converging portion 48 to an intermediate pressure, and a diverging portion 54. The system 10 also includes a control fluid port 22 for connecting to a control volume of the pressure regulating valve, the control fluid port 22 being configured to receive fluid at the intermediate pressure from the first conduit. [Fig 3]