A diapharagm pump for a bioprocess system comprises a pump head (1; 101; 201; 301) comprising: a common inlet (3); a common outlet (5); a plurality of pump cavities (7) each including at least one cooperating pair of one-way valves, the at least one pair of one-way valves including an inlet valve (9) and an outlet valve (11), wherein the respective inlet valves (9) are in fluid communication with the common inlet (3) and the respective outlet valves (11) are in fluid communication with the common outlet (5) and wherein a centre of the outlet valve (11) for each pump cavity is positionable above a centre of the inlet valve (9) for the same pump cavity when the diaphragm pump is oriented for use to inhibit trapped gas; and a plurality of moveable diaphragms (13) each respectively provided in a respective of said pump cavities (7) for varying a volume of the pump cavities. The system further comprises a pump drive (31) which is configured to transfer a motion to the diaphragms (13) of the pump head (1; 101; 201) for accomplishing a fluid displacement from the common inlet (3) to the common outlet (5) of the pump head (1; 101; 201; 301) as a result of said varying of the volume of the pump cavities (7).