By Robert Klein, Watlow Electric Manufacturing Co. |
Immersion heaters are used in a wide variety of applications in the chemical process industries (CPI). Knowing which heater to specify for a particular application and how to maintain it can make a manufacturing process more cost-efficient. This article describes the types of immersion heaters available, explains how to select them and provides guidance on installing and using the heaters.
As the name implies, immersion heaters are directly immersed in the fluids they heat. These fluids may include water, oils, viscous materials, solvents, process solutions, molten materials and gases. By transmitting all of their heat within the liquid or gas, immersion heaters are virtually 100% energy efficient.
Heater designs include numerous choices in size, kilowatt ratings (power), voltages (electrical potential), termination connections, sheath materials and accessories. Suppliers carry many units as stock items. For unusual applications, custom engineering an immersion heater is also an option.
The basic types of immersion heaters are the screw plug, flange, pipe insert, circulation and over-the-side. They are usually available in either a round tubular or flat tubular design. One design may be chosen over the other…