A pump, comprising: an inlet opening; an outlet opening; a pump diaphragm comprising an opening, provided with a passive check valve, through the pump diaphragm; and an actuating means configured to move the pump diaphragm between a first position and a second position, wherein the passive check valve is configured such that a movement from the first position in the direction toward the second position has a closing effect, and that a movement from the second position in the direction toward the first position has an opening effect, so that a pumping cycle wherein the pump diaphragm is moved from the first to the second positions, and back, causes a net flow from the inlet opening to the outlet opening; a further pump diaphragm comprising an opening, provided with a further check valve, through the further pump diaphragm; a further actuating means configured to move the further pump diaphragm between a third position and a fourth position; and a spacer arranged between the pump diaphragm and the further pump diaphragm which, along with the pump diaphragms (10a, 10b), defines a pump chamber, wherein the outlet opening is formed by the opening within the pump diaphragm and is provided with the passive check valve, and wherein the inlet opening is formed by the opening within the further pump diaphragm and is provided with the further passive check valve, wherein the actuating means and the further actuating means are configured to move the pump diaphragm and the further pump diaphragm such that the volume of the pump chamber is increased during a suction phase, and that the volume of the pump chamber is reduced during a pumping phase, wherein the check valve is configured such that a movement of the pump diaphragms (10a, 10b) during the suction phase has a closing effect, and that a movement of the pump diaphragms (10a, 10b) during the pumping phase has an opening effect, and wherein the further check valve is configured such that a movement of the pump diaphragms (10a, 10b) during the suction phase has an opening effect, and that a movement of the pump diaphragms (10a, 10b) during the pumping phase has a closing effect. an inlet opening; an outlet opening; a pump diaphragm comprising an opening, provided with a passive check valve, through the pump diaphragm; and an actuating means configured to move the pump diaphragm between a first position and a second position, wherein the passive check valve is configured such that a movement from the first position in the direction toward the second position has a closing effect, and that a movement from the second position in the direction toward the first position has an opening effect, so that a pumping cycle wherein the pump diaphragm is moved from the first to the second positions, and back, causes a net flow from the inlet opening to the outlet opening; a further pump diaphragm comprising an opening, provided with a further check valve, through the further pump diaphragm; a further actuating means configured to move the further pump diaphragm between a third position and a fourth position; and a spacer arranged between the pump diaphragm and the further pump diaphragm which, along with the pump diaphragms (10a, 10b), defines a pump chamber, wherein the outlet opening is formed by the opening within the pump diaphragm and is provided with the passive check valve, and wherein the inlet opening is formed by the opening within the further pump diaphragm and is provided with the further passive check valve, wherein the actuating means and the further actuating means are configured to move the pump diaphragm and the further pump diaphragm such that the volume of the pump chamber is increased during a suction phase, and that the volume of the pump chamber is reduced during a pumping phase, wherein the check valve is configured such that a movement of the pump diaphragms (10a, 10b) during the suction phase has a closing effect, and that a movement of the pump diaphragms (10a, 10b) during the pumping phase has an opening effect, and wherein the further check valve is configured such that a movement of the pump diaphragms (10a, 10b) during the suction phase has an opening effect, and that a movement of the pump diaphragms (10a, 10b) during the pumping phase has a closing effect.