SYSTEM OF BELLOWS AND CO-ACTING PART, PUMP AND METHOD FOR THE USE THEREOF

摘要

The present invention provides an assembly of bellows part and a part against which unrolling takes place (the unrolling part), comprising a bellows part with a flexible wall of a predetermined shape and thickness variation which co-operates with an unrolling part with a stiff outer wall along which the flexible wall is movable, wherein the unrolling part has a predetermined diameter variation and/or the flexible wall has a predetermined thickness variation so as to cause a desired development of force.