Patent ID: 6843779

Claim:
An apparatus for use in blood dialysis comprising: first and second dialyzers each containing a semipermeable membrane that divides the dialyzer into a blood compartment and a dialysate compartment, the dialysate compartment of each dialyzer being connectable to a dialysis machine; a blood compartment connecting line connecting the blood compartments of said dialyzers together in series; blood connecting lines for connecting said blood compartments to the vascular system of a patient; and a dialysate compartment connecting unit connecting the dialysate compartments of said dialyzers together in series, wherein said dialysate compartment connecting unit comprises an adjustable flow varying device for controllably setting the rate of the flow of dialysate through said connecting unit, said device being constructed to progressively vary the dialysate flow rate through said connecting unit, said dialysate compartment connecting unit comprises a flexible tube and said adjustable flow varying device comprises a roller clamp composed of a roller that is movable along a path to progressively constrict said tube, and said dialysate compartment connecting unit further comprises a hollow rod installed within, and having a smaller diameter than, said flexible tube, said roller clamp being operative to not deform said hollow rod so that said hollow rod defines a minimum dialysate flow path when said flexible tube is fully constricted.