Immersion heaters have a wide range of applications in the chemical processing industries. Knowing which heaters to select and how to install them might help save production costs.  Learn about immersion heaters, their uses, and how to select, size, specify, install, and use them.

What is an Immersion Heater?

Immersion heaters, as the name indicates, are submerged in water, oils, solvents, process solutions, molten materials, and gases, releasing all of their heat within the fluid, resulting in approximately 100% energy efficiency. Immersion heaters come in a range of sizes, kilowatt ratings, voltages, terminations, sheath materials, and accessories. They are frequently custom-designed for a specific use.

Basic immersion heater configurations include screw plug, flange, pipe insert or bayonet, circulation or in-line, booster, and over-the-side.  They are commonly offered in a round or flat tubular shape.  The flat variant can handle a larger watt density without overheating the sheath. Heaters are classified into two types: pressurized (closed) systems and non-pressurized (open tanks).

Common Chemical Applications of Immersion Heaters

Immersion heaters are used in a wide range of chemical processes. Some common applications include:

Heating Acid Baths: In metal treatment industries, acid baths are used for cleaning and etching. These baths need to be kept at a constant temperature for effective results. Immersion heaters made with corrosion-resistant materials are ideal for this.

Oil Heating: In industries where oils are used for reactions or lubrication, immersion heaters ensure the oil remains at the correct viscosity and temperature.

Solvent Heating: Many chemical reactions require solvents to be heated. Immersion heaters can safely and evenly heat solvents without the need for open flames.

Water Treatment: In water treatment plants, immersion heaters are used to maintain the temperature of process water or to help with the removal of impurities.

Chemical Mixing Tanks: Some chemical mixtures require heating to maintain fluidity or to speed up reactions. Immersion heaters make sure the temperature is consistent throughout the process.

Other Uses of Immersion Heaters:

Pressurized systems.

The square flange immersion heater is utilized in industrial water boilers and storage tanks that include degreasing solvents, fuel oils, heat transfer fluids, and caustic solutions. A round or flat tubular heater is brazed or welded to a four- or six-bolt flange, and wire connections are made using screw lug or threaded stud terminals.  These heaters are bolted directly to a companion flange that is welded to the tank wall or nozzle.  Assembly changes are as simple as unbolting the flange and changing the heater, reducing equipment downtime.

Non-Pressurized Systems

Over-the-side heaters are designed in L and O forms and mounted at the top of a tank, with the heated section buried along the side or at the bottom. Over-the-side heaters ensure uniform heat distribution. They are portable, can be readily removed for heating and tank cleaning, and offer a large working surface inside. There are several options for sheath materials, kilowatt ratings, terminal enclosures, and mounting techniques. Over-the-side heaters are meant to heat water, oils, solvents, salts, and acids. They are commonly used for freeze protection.

Conclusion

Immersion heaters play a key role in many chemical process applications by offering safe, efficient, and reliable heating. Whether you’re dealing with corrosive acids, thick oils, or sensitive solvents, there’s likely an immersion heater suited for your needs. By choosing the right type and material, industries can improve their process control, reduce energy costs, and maintain product quality. As technology improves, immersion heaters will continue to be a smart solution for chemical heating challenges.