摘要：

A dispenser pump comprises a pump chamber (25) having a flexible wall (9) for altering the volume of the chamber (25). The flexible wall (9) is a polygonal pyramid, preferably five-sided, with facets (70) interrupted by respective cylindrical surface portions (71) inclined to the facet (70) so as to induce bending thereof when the wall (9) is flexed on actuation of the pump, thereby producing a force tending to restore the flexible wall (9) to its rest condition. An inoperative condition of the pump may be achieved by relative rotation of two body parts (1,15) of the pump about the axis of a slidable telescopic guide connection between the flexible wall (9) and a relatively fixed body part (15), a discharge nozzle (12) of the pump being out of register with an outlet port (29) of the pump in the inoperative condition. The flexible wall (9), an essentially rigid boundary portion (10) thereof, an essentially rigid guide member (6,8,80) that moves with it and the discharge nozzle (12) may be formed together as a one-piece integral part (1) of e.g. polypropylene. The construction enables a large pumping volume to be swept out in a relatively small diameter using only a small number of separate pump parts.

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