A membrane composite piston pump

The present invention discloses a composite membrane piston pump comprising a pump housing containing a lumen, an eccentric shaft provided with a ball bearing on the outer surface of the eccentric shaft, an outer surface of said ball bearing is circumferentially connecting two or more plain bearings, spherical plain bearings in the upper portion from bottom to top is mounted a diaphragm and a piston, the joint bearing and a piston driven diaphragm simultaneously up or down, by the present invention in the pump housing from the inside lumen set up under the diaphragm and the piston, mainly rely on compression piston, a lot of pressure can be output, and is disposed below the piston diaphragm the pressure is small and hard to damage, but can also function as a sealing diaphragm role in addressing the shortcomings of the conventional piston pump leakage easy to meet people's requirements, the present invention is also provided with a pressure relief device, to ensure that the diaphragm pump pressure will not be too large rupture damage.