Band heaters are typically used where heat is required around the surface area of a pipe, tube or cylindrical container. They provide fast-acting indirect heating, and many industries, especially the plastics industry, find them well suited to their needs.
There are three main types of band heaters: mica, ceramic and mineral insulated. What's the difference? They are all insulators for heating elements.
Mica band heaters tend to be used where a lower maximum temperature is required. It is a good insulator for heaters because it is corrosion resistant and has good dielectric strength. It is also resistant to chemicals and water, and has some flexibility to withstand some bending. As we mentioned, it cannot withstand higher heat. While its maximum temperature is typically 900°F (480°C), it may not last very long if it has to be kept at or near that temperature all the time. However, mica tape heaters are less expensive. They can accommodate a variety of cutouts and hole arrangements, and they have many end output arrangements to choose from.
Ceramic band heaters can handle much more heat. They can typically reach 1200-1400°F (650-760°C). The ceramic segments used in these types of heaters are excellent insulators. However, because ceramics tend to be able to conduct heat, they also tend to retain heat, making proper temperature control a bit difficult. This can lead to process problems, especially in the plastics industry, due to overheating. They tend to cost a little more than mica tape heaters.
Mineral insulated heaters are well suited for high temperature applications, over 2000°F (1094°C), but they typically operate in and around the 1400°F range. They are also considered to have a very high watt density. The typical material used is magnesium oxide, which is a compacted mineral that covers the band heater and provides excellent thermal conductivity.
When it comes to your band/nozzle heating needs, you have many options. Depending on your application, you can choose the type of insulator you want to use. If you need heat at lower temperatures and want to be economical, you can choose mica, which is the most common type of insulator used in most industries. Ceramic is your best medium-temperature choice. Finally, if you need a band heater for consistently higher temperatures, you should choose a mineral insulated band heater.
