Blood treatment systems and methods

A reciprocating diaphragm pump comprising a first rigid body having a pumping chamber wall, a second rigid body having an opposing control chamber wall, and a diaphragm configured to be interposed between the pumping chamber wall and the control chamber wall to define a pumping chamber and a control chamber, the diaphragm comprising:

• a gasket arranged to locate the diaphragm between the first rigid body and the second rigid body;
• a diaphragm body having a curved, semi-spheroid or domed shape, the diaphragm body configured to generally conform to a curved inner surface of the pumping chamber wall or a curved inner surface of the control chamber wall, and the diaphragm body having a pumping side arranged to face the inner surface of the pumping chamber wall and a control side arranged to face the inner surface of the control chamber wall;
• a transition region between the gasket and the diaphragm body, the transition region arranged to be pinched or clamped between a clamping region of the first rigid body and an opposing clamping region of the second rigid body;
• wherein the diaphragm is resilient, such that the diaphragm is in a relaxed position when the control side of the diaphragm body assumes a convex shape when positioned in the diaphragm pump.

A pump cassette for pumping fluid comprising a first rigid body having a pumping chamber wall, a second rigid body having an opposing control chamber wall, and a diaphragm configured to be interposed between the pumping chamber wall and the control chamber wall to define a pumping chamber and a control chamber, the pumping chamber in fluid communication with a fluid inlet and fluid outlet of the cassette, the control chamber in fluid communication with a pneumatic control port for transmission of pneumatic pressure to the control chamber, the diaphragm comprising:

• a gasket arranged to locate the diaphragm between the first rigid body and the second rigid body;
• a diaphragm body having a curved, semi-spheroid or domed shape, the diaphragm body configured to generally conform to a curved inner surface of the pumping chamber wall or a curved inner surface of the control chamber wall, and the diaphragm body having a pumping side arranged to face the inner surface of the pumping chamber wall and an opposing control side arranged to face the inner surface of the control chamber wall;
• a transition region between the gasket and the diaphragm body, the transition region arranged to be pinched or clamped between a clamping region of the first rigid body and an opposing clamping region of the second rigid body;
• wherein the diaphragm is resilient, such that the diaphragm is in a relaxed position when the control side of the diaphragm body assumes a convex shape.