Patent ID: 7651324

Claim:
A diaphragm pump for pumping a fluid, comprising: a diaphragm having an inner peripheral portion, a first surface and a second surface; a driver including a support portion, the driver being connected to the inner peripheral portion of the diaphragm via the support portion, the driver being reciprocated to deform the diaphragm thereby performing a pumping action, wherein the support portion includes a first supporting surface for supporting the first surface and a second supporting surface for supporting the second surface, the second supporting surface including a planar region which contacts the second surface by plane contact, wherein the support portion allows the inner peripheral portion of the diaphragm to slidingly move along an interval between the first and second supporting surfaces when the diaphragm is deformed by the reciprocation of the driver; a pump chamber formed in the diaphragm pump and defined on the side of the first surface of the diaphragm, the pump chamber being changed in volume by deformation of the diaphragm; and an O-ring provided only between the first supporting surface of the support portion and the first surface of the diaphragm, wherein a minimum value of the interval between the first and second supporting surfaces is greater than a thickness of the diaphragm, so that an empty space extending along the entire radial extent of the first or second surface of the diaphragm exists between the first supporting surface and the first surface or between the second supporting surface and the second surface.