Screw actuated lift valve for water feed - uses spring piston effect to permit oscillation of retracted plunger to obviate water hammer

摘要

The lift valve may be used on domestic water feeds, using a screw (6) actuated plunger (15) to move a washer (16) relative to the control aperture (A). The plunger can oscillate relative to a screw (6) once the washer (16) is lifted off its seat (S), against the action of coil spring (5) and to a lower limit defined by ring (4). The arrangement allows the plunger (15) to adjust to prevailing water pressures and to control the through flow. In addn. the inlet and outlet pipes may have compressible bore liners (14,14a) in an appropriate elastomer. These liners may have a lesser bore than the connecting pipework (10) and a discharge-control washer may be incorporated in the outlet (37).