Valve position indication

摘要

A valve such as a butterfly valve has a manual actuating handle (16) coupled to an actuator shaft for a valve closure member (12), and a switching means is incorporated in the actuator coupling to indicate fully open and fully closed states of the valve. The switching means comprises Hall effect switching circuits potted into an annular boss (20) fitted to the valve casing (10), the actuating handle having a hub (18) which seats on the boss and rotates relative thereto when the handle is lifted to raise the hub out of locking engagement with the boss, the boss carrying a magnet which actuates the appropriate Hall effect switch when brought into proximate relationship therewith, which occurs only when the handle is rotated and lowered into its fully home locked position corresponding to the fully open and fully closed states of the valve.