Patent ID: 7175606

Claim:
A disposable unit for a medical fluid machine comprising: a generally flat body residing generally in one plane and having a plurality of corners separating a pair of opposing sides and defining a space between the sides, the body configured and arranged to be placed inside of the machine; and a plurality of membranes sealed to the generally flat, planar body along the opposing sides, the body and the membranes forming at least one medical fluid pathway in the space between the opposing sides, wherein at least one of the opposing sides are bowed in a direction residing within the plane, the sides further having at least one of: (i) enhanced rigidity due to the bowed sides and in a direction lying within the plane of the body to aid placement of the body and sealed membranes inside the machine and (ii) reduced distortion due to the bowed sides from a process used to seal the membranes to the frame.