Band heaters, also known as knuckle heaters or barrel heaters, are a variety of heating element that provides direct or radiant heating by clamping around nozzles, pipes, or cylinders. Band heaters are used primarily in metal and plastic forming processes, such as extrusion, and are similar to strip heaters in terms of application and configuration. The range of temperature that band heaters provide can vary from 300 to 1400 degrees Fahrenheit (approx. 149 to 760 degrees Celsius). Strip heaters can also be clamped or bolted in order to achieve the direct transfer of heat to either the air or a solid object.
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Applications of Band Heaters
Band heaters, along with other types of heating equipment, are a necessity for numerous industrial processes, especially extrusion, since the process involves melting materials and maintaining their plasticity in order to prepare the materials for extrusion. The extrusion process generates friction, which in turn generates heat, and the heat that band heaters provide act as a supplement. Band heaters are capable of providing efficient and direct heat in oddly shaped areas that would act as a hindrance for any other type of heater.
Band heaters are used in a wide range of applications, including:
- Chemical and Food Processing
- Wire Processing
- Front End Extrusion Heating
- Blown Film Extruding
- Metal Injection Molding
- Plastic Extruding
- Plastic Injection Molding
Notable Types of Band Heaters
- Tubular Band Heaters
- A type of band heater that are larger in diameter and cover a greater surface area. Their width enables them to provide a higher amount of heat to a narrower nozzle or cylinder. Band heaters are commonly used in manufacturing or processing equipment to heat the air in small volumes. They can also be used to melt ice in gutters and troughs and are able to keep them completely free of snow and ice during the winter if they are properly powered and insulated. Band heaters usually provide conductive heat to substances, such as polymer-metals and plastic. They can also be used for convectional air heating, which is defined as the transfer of heat through liquids and gasses. In addition to their ability to quickly produce heat, another advantage that band heaters have is quick and easy installation due to their clamp-on structure.
- Ceramic Band Heaters
- Protect the heating element from materials in a certain application, such as dripping grease within an oven. Ceramic insulation is valued by many industries because of its ability to distribute heat safely and effectively while significantly reducing the risk of fire. Popular applications of ceramic band heaters include injection molding, die heads, extruding equipment, and acting as a heating agent in chemical reactors. The temperature of a ceramic heater can reach up to 1200 degrees Fahrenheit (approx. 649 degrees Celsius).
- Mica Band Heaters
- An inexpensive insulating agent that possesses excellent strength and is able to allow heat to transfer through the heater’s sheath and into the object that requires the heat. There are some varieties of mica band heaters that are encased in various types of metals according to the specific needs of the application and also feature a resistor wire or ribbon that wraps around a mica core and is attached to stainless steel posts or nickel alloy wires. The former allows the distinct feature of slippage as opposed to being twisted off. The use of mica greatly reduces the mass of the heater, which subsequently accelerates the transfer of heat and keeps production costs to a minimum. Mica insulated heaters are commonly used in laboratory tests, heating pipes, blow molding, autoclaves, extrusion, and injection molding. Mica insulated heaters can reach a maximum temperature of anywhere between 300 and 800 degrees Fahrenheit (approx. 149 to 427 degrees Celsius).
- Mineral Band Heaters
- Made from stainless steel are capable of reaching temperatures as high as 1400 degrees Fahrenheit (760 degrees Celsius). All of these materials can also be used to insulate strip heaters. Insulation assists in the prevention of short circuiting, and the protection of heating elements from exposure to chemicals or other elements that could be detrimental to the equipment’s performance.
Factors to Consider When Purchasing Band Heaters
Band heaters are available with a variety of features and are highly praised by many industries because they are safe and cost efficient in providing heat for a particular application. Configurations vary in terms of size and what material is used to insulate them. Therefore, it is recommended to consult a band heater manufacturer to ensure that you find the heater your application requires.