What is a Screw Plug Heater?

A screw plug heater is a subcategory of immersion heaters, which typically requires small space to operate. The principle of screw plug heaters is similar to the flanged immersion heaters. The heater is immersed into the wall of the equipment, such as vessels, water tanks or chemical containers. Screw plug heaters usually supply heat to smaller liquid containers that require precise heater control.

This type of electric heater is capable of heating various liquids such as water, oil or another chemical medium. As well, the heater maintains a pre-set temperature under mildly or severe corrosive condition. When the tubular heating elements are exposed to the medium, a natural convection current generates as the sheath heats up. This heat dissipates around the medium uniformly up to the top of the equipment.  

In contrast to flanged immersion heaters, the hairpin-shaped tubular element is welded into a casing or a pipe threaded fitting instead of a flange. Installing additional thermowells can provide more accuracy and improve temperature control. This is in order to prevent issues such as the thermal degradation of the medium. Screw plug heater is very efficient in terms of cost and performance for freeze protection, water storage and boilers.

Our standard models are categorized under different specifications based on their application. This ranges from municipal water temperature control to fuel oil storage. Each model varies in power, immersed length, watt density, terminal enclosure type and other parameters to fit different application needs. In addition, a temperature control thermostat can be installed to include an additional heating control in order to maintain the desired temperature setpoint of the medium.  

Screw Plug Heater

A Screw plug heater can be used in a small vessel containing temperature sensitive medium. In order to consistently regulate the fluid temperature, control panels are installed to prevent overheating the chemical in unique heat transfer systems. This overheating reaction is known as the thermal decomposition, which is usually an endothermic reaction that involves with excessive heat causing the chemical bonds to break over an undetermined period. Installing a control panel is the best solution to protect your valuable chemicals and electric heater from potential thermal damages.  

Control Panels

Our control panels are designed to be simple to use while including multiple functions for different industrial heating applications. Examples of important features include electrical unit metering (Current, voltage and wattage), remote setpoint control, alarm, proportional control signal, etc. The selection of the control panel housing is based on the application’s operating environment.

A variety of terminal enclosure types are available for the control panel housing, ranging from general purposes use (NEMA type 1) to explosion/moisture proof (NEMA type 7). And of course, by contacting our office, we are more than happy to assist our clients for the selection of our electric heater products and thermal control systems.

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