Patent ID: 8888469
Filing Date: 2014-11-18
Classification: F04B

Abstract:
1. A hydraulically-controlled diaphragm pump comprising; a pump chamber formed between a pump head and a pump body with a movable wall formed by a diaphragm that is elastically deformable from its rest shape that corresponds to its state at the end of a suction stroke of the pump, an intermediate hydraulic chamber formed in said pump body adjacent to a pump chamber level with the diaphragm and including a piston driven with reciprocating motion inside said intermediate hydraulic chamber, the volume of the intermediate hydraulic chamber being theoretically constant but varying in service as a result of leaks between the piston and a guide for guiding the piston's reciprocating motion, a leak compensation volume for compensating said leaks from the intermediate hydraulic chamber being connected thereto by a top-up channel via a free check valve that is not rated and that passes fluid towards the intermediate hydraulic chamber, wherein the check valve and at least a portion of the compensation volume are housed in a separate body fitted to the pump body at a highest point of the intermediate hydraulic chamber in a working position of the pump.