Non-return electric diaphragm pump and liquid feeding and pumping method thereof

The non-return electric diaphragm pump comprises a pump body and a motor, a liquid inlet flow channel and a liquid outlet flow channel are formed in the pump body, an umbrella valve and a water outlet diaphragm are arranged in the liquid inlet flow channel and the liquid outlet flow channel respectively, and the pump body comprises a water inlet and outlet cover, a non-return sealing gasket, a non-return seat and a compression bowl. A pagoda spring is arranged between the water inlet and outlet cover and the non-return sealing gasket, and the water inlet and outlet cover is further provided with an inner liquid storage channel which is parallel to the liquid inlet flow channel of the water inlet and outlet cover and opposite to the piston cavity of the compression bowl. And the opening end of the inner liquid storage channel is communicated with the liquid outlet end of the liquid inlet flow channel on the water inlet and outlet cover. According to the technical scheme, the diaphragm pump is good in sealing e