Improvements relating to flow control valves.

摘要

A flow control valve comprises a valve housing (1) of generally circular cross-section. A valve member (3) lies within the housing, the valve member being in the form of a section of a right circular cylinder subtending an angle of 180 DEG to the axis of the cylinder and lying between two planes 4 and 5 that each include and lie along an axis B-B about which the valve member is pivoted. The pivotal mounting is by diametrically opposite pivot means, one at each side of the housing. The hosing includes a dome (11) defined from a centre at the point where the pivot axis intersects the axis of the housing. Means are provided for pivoting the valve member through substantially 90 DEG between an open position lying adjacent to the dome and in effect forming a continuation of the passageway through the valve housing and a closed position lying across the passageway to close the housing to flow of material therethrough. Part of the valve member is accommodated by the dome during such pivotal movement and means are provided for effecting sealing between the valve member and the valve housing in the closed position.