Patent ID: 6514177
Filing Date: 2003-02-04
Classification: A61M,F04B

Abstract:
A diaphragm pump for supplying gas for an inhaling apparatus, comprising:upper and lower housing members defining a chamber therebetween; a flexible diaphragm having an outer edge and a first opening defining an inner periphery, the outer edge of the diaphragm being held between the upper and lower housing members; a lower diaphragm disc having a second opening; an upper diaphragm disc having a third opening, each of the lower and upper diaphragm discs having a diameter smaller than the diameter of the diaphragm, the diaphragm being held between the lower and upper diaphragm discs with the inner periphery of the diaphragm abutting a stop member; a securing member extending through the first, second and third openings to clamp the diaphragm between the lower and upper diaphragm discs; a diaphragm drive device for driving the lower and upper discs and the diaphragm in a reciprocating manner; wherein the diaphragm is shaped so that, when the outer edge of the diaphragm is not held between the upper and lower housing members, a first portion of the diaphragm outside the periphery of the upper diaphragm disc extends in the direction of the upper diaphragm disc, and when the diaphragm is held between the upper and lower housing members, the first portion of the diaphragm forms a substantially toroidal protrusion extending in the direction of the upper disc member, the protrusion being present throughout the reciprocating movement of the diaphragm.