Pilot valve for a pressure reducing valve

摘要

A pilot valve (2) for controlling operation of a hydraulically-actuated pressure reducing valve, the pilot valve including a housing (4), and a first valve member (15) mounted in the housing for longitudinal movement along an axis relative to the housing and to a second valve member (22) in response to the outlet pressure of the pressure reducing valve. The first valve member is provided with an aperture (20) and the second valve member comprises a closure portion which varies the effective flow cross section of the aperture in accordance with relative longitudinal movement between the first and second valve members. An adjuster (26) controls the relative rotational position of the first and second valve members, the closure portion having a profile such that relative rotation between the first and second valve members causes the closure portion to vary the effective flow cross section of the aperture (20).

主权项

1. A fluid supply system comprising (i) a fluid-actuated pressure reducing valve and (ii) a pilot valve connected to the fluid-actuated pressure reducing valve for controlling an output pressure of the fluid-actuated pressure reducing valve, the pilot valve including:
a housing, a first valve member and a second valve member whose relative positions control flow through the pilot valve; the first valve member being provided on a movable spring-engaging member which engages a spring and which is mounted in the housing for movement relative to the housing in a longitudinal direction in response to the outlet pressure of the pressure reducing valve, movement of the spring-engaging member changing the relative positions of the first and second valve members; an adjuster for varying the relative rotational positions of the first and second valve members about the longitudinal direction for a given position of the spring-engaging member, so as to cause the output pressure of the pressure reducing valve to alter; and a motor connected to the adjuster for rotating the adjuster; wherein one of the first and second valve members includes an aperture directed laterally of the longitudinal direction; the other of the first and second valve members includes a portion defining an edge which is positively-inclined relative to the longitudinal direction, and which extends completely across the aperture, and which is arranged for relative sliding movement across the aperture to vary the flow cross section through the aperture and thus the flow through the pilot valve; and the adjuster is arranged to adjust the relative rotational positions of the edge-defining portion and the aperture by sliding movement so as to adjust the flow cross section through the aperture for a given position of the spring-engaging member.