The reciprocating pump for the output of various gas and liquid consists of connector, oil cylinder, oil cylinder head with inlet and outlet valves, and the piston rod, which is in the center hole of the connector and has pistons on its two ends. It features its change-over movable valve rod, which is inside the connector, and has notches corresponding to the oil ports for the automatic commutation. The structure of the present pump is different from the available techn which has a structure with the piston rod used as valve rod, and the connector used as valve body. |