Peristaltic dialysate solution pump

Hemodialysis apparatus for treatment of blood to remove waste impurities therefrom, including:

• dialyzer means through which waste impurity-containing blood and a dialysate solution are passed in indirect mass transfer dialyzing relationship for transfer of said waste impurities from said blood to said dialysate solution;
• means for transferring waste impurity-containing blood from a patient to said dialyzer means including a flexible resilient tubing pumping section through which blood is pumped and means for returning waste impurity-depleted blood to said patient forming a blood flow circuit;
• means for transferring dialysate solution from a negative pressure dialysate solution source to said dialyzer means and means for discharging waste impurity-enriched dialysate solution from said dialyzer means forming a dialysate solution flow circuit including a flexible resilient tubing pumping section through which dialysate solution is pumped;
• peristaltic blood pump means disposed in said blood flow circuit and peristaltic dialysate pump means disposed in said dialysate solution flow circuit each pump means comprising a rotatable pump head assembly including a base member positioned for rotation about a fixed axis with a plurality of circumferentially spaced apart rollers mounted thereon for independent rotation about respective axes parallel to the base member fixed axis, at least said peristaltic dialysate pump means having four spaced apart rollers mounted on the base member thereof;
• means for anchoring the end segments of the flexible resilient tubing pumping section in said blood flow circuit and means for anchoring the end segments of the flexible resilient tubing pumping section in said dialysate solution flow circuit such that the tubing in each circuit is tensionally extended around the pump head assembly of a respective one of said peristaltic pump means and is simultaneously engaged and compressed by at least two of said circumferentially spaced apart rollers of the respective peristaltic pump means, the rollers of each peristaltic pump means being mounted for longitudinal movement of the points of compression along the associated tubing during rotation of said pump head assembly to advance fluid through said tubing;
• each of said four rollers in at least the peristaltic dialysate pump means having a generally convex surface profile, for only partial closure of the tubing at the points of compression by the rollers, with a maximum diameter between 0.25 and 0.75 inch and circumferentially spaced 90.degree. apart from adjacent rollers with a radial distance between the roller axis and said base member fixed axis of from 0.50 to 1.50 inches;
• said flexible resilient tubing pumping section in the dialysate flow circuit having a length, as measured longitudinally along the tubing between the anchored end segments thereof, of from 6.75 to 11.0 inches, a wall thickness of from 0.07 to 0.125 inch, and an internal diameter of from 0.18 to 0.35 inch;
• and drive means coupled to the pump head assembly of the peristaltic dialysate pump means for rotation thereof at a speed in the range of from 150 to 400 rpm.