Control valve for pressure fluid - admits second medium at equal pressure to chamber of actuating motor

摘要

The control valve has inlet and outlet paarts for a first medium under pressure, and a needle in a chamber between the parts, movable to and from the outlet to adjust the free cross-section and coupled to the shaft of an electric motor. The latter is separated from the chamber by a wall through which the needle passes. A supply is provided for the admission into the motor chamber (8) of a second medium at the same pressure at least as the first one flowing through the valve.