Heater in Kidney Dialysis Machine


Kidney dialysis machines purify the blood in patients whose kidneys have failed. Keeping the blood at body temperature to prevent thermal shock and heat water for a better job of cleansing the blood at higher temperatures is vital to this process.


Watlow engineering worked with the customer in perfecting this application:

  • A 0.125-inch (3 mm) thick flange attached to the 0.625-inch (16 mm) diameter by 7-inch (18 cm) long FIREROD® heater. The flange kept the FIREROD concentric with the plastic tube (which would melt if near the heater). The customer was assured of a flange perpendicular to the FIREROD by a one-hundred percent inspection of the units by Watlow.
  • Passivation was necessary so that rust would not enter the water which mixes with the blood.
  • -Since this was "patient care equipment," a Type LL (special low leakage) FIREROD heater capable of maintaining leakage below 15 micro-amps (0.0000015 amp) had to be supplied.