A global leader in medical services contacted Tempco to design a small, inline circulation heater to warm a saline solution in a portable hemodialysis system. The machine will be used in remote areas where dialysis clinics are scarce. Important goals to keep in mind for this project were:

• Keeping the machine low-mass
• Rugged construction that can stand up to consumer use
• Corrosion resistance for long-term use
• Heater effeciency that would keep power consumption low
• Cost-effeciency without sacrificing quality

Addressing the first two points led Tempco to design a cartridge-type inline circulation heater with a small diameter. This type of heater helped to keep machine components light-weight enough to be portable.  It also allowed Tempco to utilize a design that is durable for every day use.

To help with corrosion, a 316 stainless steel construction was used for the heating element and for the housing. The metal parts were Electro Polished to further improve the corrosion resistance of the assembly. A hydrostatic pressure test was performed on each individual heater to ensure that every heater meets the application requirements.

As with any medical application we encounter, preventing the risks and the harm that might occur to the patient is paramount. To that end, several steps were taken regarding powering and controlling the heater.

• Because this is a sensitive application, the heater was designed with a built-in thermocouple to assist with controlling the temperature, keeping the saline in a specific temperature range.
• To improve efficiency a silicone sleeve insulator covered the outside pipe, increasing the temperature by 10-20°F without drawing more power and reducing the heat-up time.
• Performing a Low Leakage Test that complies with the UL Standard for Safety Medical Electrical Equipment was part of the requirements of designing this heater.
• Another distinctive design feature of this miniature circulation heater is the dual voltage construction. Because the heater will be used in different parts of the world, covering both 120 and 240V power supplies allows our customer to use a single part and still maintain safety.

Tempco was able to minimize the cost of this heater while still providing the best quality product for a medical device. This was accomplished with intimate discussions between the customer, our engineering team and our production team. Prototypes of this process heater were provided in a timely manner and our customer was able to start the testing and the validation in record time.

With this new portable dialysis machine, many people who are suffering in rural areas will not have to travel to a city to seek medical treatment anymore. For the first time they will have access to this critical procedure close to where they live.

Heater and insulating sleeve during testing