| 摘要 |
<p>The invention, as applied to a water dispenser (10), comprises a dispensing mechanism securely mounted within a casing (12) mounted on top of a water standpipe set into the ground. The dispenser (10) is operated by way of a manually rotatable hand wheel (18) that has a turning handle (20). Rotation of the hand wheel (18) causes an impeller of a viscous coupling within the casing (12) to couple to a valve actuator located within the casing (12). The viscous coupling rotates the valve actuator against a spring bias to act on a valve constituted by a valve closure mounted on a magnetic armature and a permanent latching magnet that is adapted to latch the valve closure armature in the open position of the valve upon application of an external magnetic force. Permanent opening and closing magnets are mounte d on the valve actuator. On rotation of the hand wheel (18) and the consequent rotation of the valve actuator, the valve opening magnet is applied to the valve to draw the valve armature to the valve opening position and to retain it there for as long as the opening magnet remains in position. As soon as hand wheel rotation stops or falls below the minimum rotation required, the spring bias counter-rotates the valve actuator and returns it to a position in which the closing magnet is applied to the valve to return the valve armature to the valve closing position.</p> |
