Flat heaters are mainly used in extruders and blow molding heads in the plastics industry. Other applications include packaging machines and general heating of containers, pipes and flat metal surfaces.
The distinguishing feature of these elements is that the heat is evenly distributed over a large surface area.
The structure is composed of heating wires and insulated with mica plates or ceramic formers. Components are usually metal encapsulated to improve mechanical strength.
The mica insulating layer has a thin structure (approximately 4mm) with a maximum watt density of 3.5 W/cm², and can work at a high temperature of 380°C.
For process temperatures exceeding 280°, ceramic insulation is preferred.
The structure of the ceramic element is thick (12mm), but the watt density is 5.5 W/cm², and the working temperature is as high as 600°C.
Generally, ceramic components are more durable than mica components, which offset the higher price and longer life expectancy.