A silicone heater is a flat, flexible device consisting of etched foil or wire wound elements embedded in silicone rubber sheets or strips. It is used where heating is required in very tight spaces and on or around complex shaped equipment. Common applications of silicone heaters include optical equipment, laser printer circuitry, and aircraft instrumentation. Silicone heaters may be acquired as off-the-shelf units or as custom made parts for specific applications often featuring reinforcing fibers to increase the durability of the sheets. The heaters may be simple, flat sheets or more sophisticated units which include auxiliary parts such as thermostats and digital temperature readouts.
Heating of equipment to maintain optimal operating conditions is often difficult when limited internal space, complex profiles, and weight saving issues are involved. It was these realities which led to the development of the silicone heater for the aerospace and defense industries. The first examples of silicone sheet heaters were made for aircraft instrument panels, satellite equipment, missile guidance systems, and radar installations. The silicone variant gave designers the ability to include space saving, light, and highly efficient heaters in any conceivable shape in applications where conventional heat sources would have been impossible.
The silicone heater is an extremely simple device which has, at its core, the unique heat resistant and flexible characteristics of silicone rubber. It is the rubber's ability to withstand temperatures in excess of 400°F (204°C), while still retaining its shape and flexibility, which makes the silicone heater concept a reality. The heaters typically consist of thin silicone rubber sheets or strips with either etched foil or wire wound heating elements embedded in their surfaces. When an electric current is passed through the element, it heats up without damaging or distorting the silicone sheet. The sheets can be inserted into spaces no larger than the their thickness, wound around tubular equipment, or molded into complex shapes for use on printed circuit boards.
Although both etched foil and wire wound silicone heater types serve the same purpose, each has its own advantages. Etched foil heaters can produce higher power outputs and are capable of complex heating patterns. Wire wound heaters are stronger, more flexible, and can be produced in larger sizes. Both may be presented as simple flat heater elements or include auxiliary parts such as adjustable thermostats or digital temperature readouts. Silicone heaters are moisture and chemical resistant and may be cemented onto heat sinks or directly onto the equipment they heat.
