Immersion Heater and Heater Elements

The heating of liquids in tanks and maintaining the temperature is a major requirement in many of the metal finishing industries. Pickling metals in acid or caustic solutions prepare the metal surface for further treatment. Gas or Oil fired immersion heaters have been proven to be economical and efficient heating methods for these applications. Specially designed burners that swirl the flame to ensure the greatest possible heat transfer through the wall of the immersion tube, together with all the necessary pipe trains and safety equipment, can be supplied by The Combustion Group.

Immersion Heaters and their Benefits

There are many reasons why metals are treated in liquids and why the liquid should be heated when it is.

Oil Treatment – Metals need to be cooled down to be set, but much the same as the heating process, cooling down needs to be done gradually to avoid thermal shock and damaging the metal. While this process was once done with water, the water would boil too rapidly for effective slow cooling.

Oil, however, retains heat more easily and allows the metal to cool at a slower rate. When heated with immersion heater elements, the oil can stay at a consistent heat to slow the cooling process even further or allow the metal to stay at high heat when immersed.

Pickling in Acid – During any stage of the smelting process metals can become stained or blemished, or harbour impurities such as rust and scaling. By pickling the metal in an acid bath, you can strip it of impurities, scaling, and discolourations. The acid is heated with immersion heater elements to prevent thermal shock from rapid cooling.

Caustic Soda – This treatment works much the same as acid, and prepares the surface of the treated metal for further metal treatments and metalworking processes. Caustic soda is highly corrosive, so like acid, you should carefully monitor your metals to avoid damaging the metal.

Water heating – Our immersion heaters can be used to superheat water, as water quenching still has its place in the metalworking industry. To avoid rapid cooling and water evaporation, the water is heated to reduce thermal shock and avoid rapid bubbling/evaporation. Water can also be used to clean your metals after they’ve been treated or acid bathed.

Heat Distribution

Much like all processes in metalworking, an even distribution of heat is essential for the quenching process. This is achieved by placing heater elements throughout the tank, and often the liquid is continuously swirled around the tank to heat the liquid more efficiently and evenly. This also helps you to save costs on running your immersion heater tanks.

Immersion Heaters for Various Industries

Immersion heaters can extend beyond the smelting and metalworking industry; wherever you need liquids heated, The Combustion Group is on hand to provide immersion heater elements and all the parts and piping that come with them.

We have extensive experience providing liquid heater elements to various companies across South Africa, including Nampak, Cape Gate, Guestro Wheels, and Crabtree. Contact us to learn more about our immersion heater tanks and their applications.

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Contact Us

Call us on the numbers below or fill in the contact form and we’ll get back to you as soon as possible.


PO Box 459 28 Mopedi Road, Edenvale Sebenza, 1610 South Africa
Tel: 011 452 5060
Fax: 011 609 5773/ 2405


150 Greyling Street Pietermaritzburg 3201 South Africa
Tel: 033 342 0160
Fax: 033 345 7052

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