US Patent 6877419 Composite diaphragm for diaphragm pumps

A composite diaphragm for diaphragm pumps comprises an elastomer body and a polytetrafluoroethylene (PFTE) coating on its back side. The elastomer body has a shape of a circular dish that has an edge region with a clamping area, a bottom and a flexible section of the diaphragm that connects the edge of the dish with the bottom. The flexible section of the diaphragm comprises a multitude of naps forming elevations on the coated side of the elastomer body. The PFTE coating is a plane ring surface with the area of the flexible section of the diaphragm.