Cast-in heaters are made-to-order tubular or wire heaters cast into a part that is designed to be an integral component of a larger piece of equipment. Geometry, materials, and connections are custom designed for specific machine applications. Specialized cast-in heater elements include strip heaters, bolt heaters, explosion resistant heaters, bushing heaters, and bottom outlet heaters. Cast-in band heaters are used to heat pipes or other cylindrical objects. Cast-in circulation heaters are used to heat a circulating gas or liquid. Cartridge heaters are used for molds, dies, platens, hot plates, and fluid heating. A cartridge heater can be made with various diameters, lengths, wattages, and voltages. Cast-in pedestal heaters provide uniform surface temperatures and can be used for fabricating semiconductor wafers. Air-cooled cast-in heaters operate with less maintenance and longer life than liquid-cooled cast-in heaters. Aluminum cast-in heaters are used to heat and control extruders, compression molding platens, heat sealers, and vacuum forming platens.
Product specifications for cast-in heaters include watt densities in W/cm2 or W/in2, maximum temperature (e.g., 400° C), accuracy of temperature control (e.g., +/- 2° C), required start and finish temperatures, maximum flow rate of material(s) being heated, required time for start-up heating, process cycle times, weights and dimensions of both heated material and containing vessel, power supply requirements, temperature sensing methods and location. Cast-in heaters can be made from aluminum, bronze, stainless steel, titanium, or other materials. To heat sensitive material like chocolate, oil, or other food products, a cast-in heater can be sheathed in quartz, INCOLOY® or INCONEL®. INCOLOY and INCONEL are registered trademarks of Special Metals Corporation.
Cast-in heaters meet the standards required by the applications in which they are used. For example, when used in refrigeration equipment, the heater seal must meet UL 471, Standard for Commercial Refrigerators and Freezers. Cast-in heaters can be recognized under the Component Recognition Program of Underwriters Laboratories (UL) Inc.