Other Case Studies:

• Convection For Heat Cure In Medical Appliances Bring Healthy Solutions
• An Executive Synopsis

Ventana Medical Systems, Inc. of Tucson, AZ, manufactures a genetic testing system designed to automate hospital pathology, reference, and R&D labs. This system handles up to 40 slides at a time, as they rotate on a carousel.

A key objective for the second-generation GenII was to address three performance problems associated with the incumbent, forced-convection system:

1. The need to reach temperature quickly and cool down rapidly

2. A non-uniform thermal profile

3. Lack of performance repeatability

Ventana Medical Systems turned to Thermal Circuits, Inc. of Salem, MA, for a cure to their heater issues. Input provided by Ventana about its application, as well as tests performed at Thermal Circuits, resulted in a workable solution of an etched-foil heater.

For the Ventana slide-staining system, Thermal Circuits recommended an infrared emitter panel as the heater. The infrared heater’s construction is a flat-foil conductor circuit, which is adhered to a ceramic insulator substrate by a thin coating of proprietary, high-temperature, ceramic binder.

Thermal Circuit’s solution of an etched-foil, infrared emitter heater met Ventana Medical Systems’ objective and solved all three problems by:

1. Implementing an element with inherent low mass/low thermal inertia properties. Specifically, the element is a foil measuring only 0.002” thick. Combining this with the element’s positioning of just a few thousandths of an inch below the heater surface affords the rapid response time required by the Ventana appliance on both heat-up and cool down.

2. “Profiling” of the element or varying the watt density across the face of the heater. This strategy compensates for heat losses along the periphery and other heat sinks while yielding a uniform thermal profile across each of the 40 slides.

3. Providing an etched-foil heater guarantees repeatability from infrared ring to infrared ring. This is realized through Thermal Circuits’ photo-etched process that fosters consistency from part to part and within each part.

Curing ill-performing thermal systems requires expert diagnosis and root cause determination by engineers trained in heat transfer and thermal analysis. Thermal Circuits’ team of application, design, and quality assurance engineers are uniquely qualified to provide your company with solutions to ensure your successful thermal application.