Method of operating a pump and pump

A even gas is mixed into the liquid in the pump section, to provide a pump that can be sent to ensure liquid discharge portion through the suction unit. By expanding the A volume pump unit 1 for discharging the liquid L by reducing the inhalation and the volume of liquid L, the suction unit 3 for sucking the liquid L in the pump unit 1, pump unit 1 and the discharge portion 5 for discharging the liquid L, to suppress the suction side check valve 4 from the liquid L is flowing back from the pump unit 1 to the suction unit 3, the liquid L from the discharge portion 5 to the pump unit 1 in the pump and a suppressing discharge-side check valve 6 from flowing back, in a state where the pump unit 6 inhales the liquid L, and further comprising a communicating portion 6b that communicates with the pump unit 1 and the discharge unit 5 to. .FIELD 1