PUMP INCORPORATING REGULATED VENTING MEANS

摘要

The invention provides a pump comprising at least one diaphragm or cylinder movable in a reciprocating manner within a chamber, sealing means located between the diaphragm or cylinder. and the interior wall of the chamber and venting means for venting a portion of the chamber bounded by the interior wall, the diaphragm or cylinder and the sealing means, wherein the venting means incorporate pressure regulating means such that the pressure to which the said portion of the chamber is vented can be regulated. This reduces the pressures difference across the or each sealing means and thus reduces deterioration and damage.