Single-shaft liquid suction and injection device

The single-shaft liquid suction and injection device comprises a base, a top plate parallel to the base and a hook, the top plate is connected to the base through a lifting assembly, a swing arm and a hook guide rail are arranged on the side face of the base, and the hook is in sliding connection with the hook guide rail through a hook fixing base; a swing arm reset piece is arranged between the swing arm and the base, one end of the swing arm is hinged to the base, and the other end of the swing arm is clamped in a limiting groove of the hook fixing base so as to prevent the swing arm from rotating clockwise. The swing arm is provided with a movable baffle, a solid-liquid separation needle and a downward pressing arm are arranged on the bottom face of the top plate, when the lifting assembly drives the downward pressing arm to descend, the downward pressing arm drives the movable baffle to rotate clockwise, and when the lifting assembly drives the downward pressing arm to ascend, the downward pressing arm dr