Heater in Kidney Dialysis Machine

Problem:

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.

Solution:

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.