Membrane washer for lift valve alternating pump - is fixed by clamping window edges between connecting rod nose and membrane to give total support

摘要

The lift valve utilises a flexing membrane (5) to control a through flow, and may be incorporated in an alternating pump. It includes a laminar washer (7) to provide total membrane support during pressure reversals. A con-rod (4) imparts movement (6) to the membrane, the washer being fixed by a clamping of central window edges (7a) between a rebated rod nose (4b) and the centre of the membrane. The constitution and thickness of the washer may be such that its hardness nominally exceeds that of the membrane, and its external dia. (7d) may be nominally less than that defining the membrane boundary. Alternatively, the washer may be nominally oversize to obtain a radial precompression effect.