Further studies on the realization of a cold carbon portable artificial kidney

Optimal conditions have been determined for the realization of a closed-loop, cold carbon, portable artificial kidney to depurate the dialysate of urea and other catabolites. It has been noticed that a dialysate flow rate of about 250 ml/min represents an optimal compromise between urea mass transfer through the dialytic membrane and its mass adsorption on cold carbon. Under this condition, the use of a 2-kg carbon column to remove urea is satisfactory for a routine dialysis treatment. Our experiments have been performed on simulated dialysis. A portable cold carbon artificial kidney requires a cooling unit and a heat exchanger to recover the power necessary to produce the 0 degrees C temperature. A flat heat exchanger, consisting of three superposed plates, with a heat exchange surface of about 0.09 m2 and a total coefficient of thermal exchange Ht, of 380 Kcal/m2-degrees C-hour has been chosen. With heat recovery, the cooling power required is 1/3 hp to allow for parasitic cold losses and the power necessary to reach a steady state. All mechanical parts necessary for heating and cooling weigh about 12 kg.