Circulation Heaters
The powerful machines that are circular heaters are necessary for many processes such as desalinization, plastic machining, gasoline refining and food manufacturing. Similar to an immersion heater, there are two common types of circulation heaters. Screw plug and flanged heaters each have tubes or coils concealed in a sheath, which is heated and transfers heat; they differ in the application and placement of these elements. While some circulation heaters consist only of this immersed heating element and an external connector, others have piping and tank components that are integrated into the pre-existing pipes or ductwork through which the air or fluid flows. Circulation heaters are easily installed, requiring only basic wiring and piping to be connected to the existing system, or in simpler variations simply plugged in and inserted into an open stock tank. Special mounting brackets and jacket supports are available for heaters using extreme temperatures to allow for inherent vessel expansion and contraction without causing damage to the unit. Additional features include adjustable thermostats, cooling options, explosion proof housing and corrosion resistant finishes.
As circulation heaters vary greatly in temperature maximums, size and other essential qualities, there are many elements to consider when selecting the proper unit for a given task. Required AC voltage, heater height, inlet and outlet separation, passivated or electro-polish finishing, diameter and nominal pipe diameter should all be carefully considered. Element watt density is one of the most important system requirements to ensure efficiency and safety. This is the amount of wattage per square inch that the circulation heater can deliver. A watt density that is too low will not fully heat the materials while a watt density that is too high will cause damage to heat-sensitive materials. The composition of the sheath is also crucial to the success of a heating unit. Low carbon steel, nickel and chromium alloys, copper and stainless steel are all common options. The selection of sheath is largely determined by the gases and fluids intended to be forced through a heater. Corrosive materials, for example, would need a stainless steel sheath as it would provide additional corrosion resistance, thereby improving the longevity of the heater. Tar, petroleum oils, asphalt, wax, potable water and inorganic chemicals are just a few of the substances heated in circulation heating systems.
