Bellows pump with bellows between the operating chambers

摘要

The pump consists of two operating chambers (11,20) with a bellows (10) located in-between the chambers, and an axially sliding piston (30) operating in conjunction with the second chamber. The piston has a bypass flow channel (31) with one end connected permanently to the chamber, and the other end with a second opening (33), which only connects to a fluid chamber (25) when the piston is at either end of its stroke. When connected, a first opening (32) connected to the second chamber is located close to the upper part of the chamber. The second opening lies higher than the first.