Cyclic Heating Exposure Protection

Need

Protect an electronic control box subjected to cyclic heating

Technical Assessment

Traditional insulation could not meet cost, and more importantly, space limits.

Solution Engineering

High heat capacity material slowed heating rate to keep electronics cool.

Validation

Prototype testing confirmed dramatic reduction in heating levels.

Lydall recognizes that cost and space constraints are key concerns during design, manufacture and commercialization of appliances.

In this case, a manufacturer of electronic control boxes for the appliance industry asked us to find an inventive solution to keep their boxes cool as they passed through a series of heated ovens.

Understanding the thermal requirements of the control box required an analysis of the appliance heating cycles. Thermal modeling was used to establish baseline thermal performance using standard insulation material. The modeling showed that the thermal environment of the control box was in flux due to short heating cycles. Even with the insulation, the box was heating well above the limit in each oven cycle -- interfering with the proper response from the control box during end use.

The transient nature of the heating cycle provided an alternate path. Traditional insulation will reduce heat transfer but will rapidly reach steady state because it has little thermal mass. By changing to a high heat capacity material, Lydall could slow down the temperature response of the insulation and prevent the system from approaching steady-state conditions and overheating the box.

It was critical to our customer that we find an option that would meet both the cost and performance requirements. Lydall used our thermal modeling capabilities to test several combinations of insulation and high heat capacity materials. Our modeling efforts allowed us to perform these tests at minimum cost and without safety risks.

The best concept was fabricated and installed with thermocouples to assess the temperature response, and a dramatic reduction in maximum temperature took place as the thermal cycles were slowed.