In immersion heaters the heat is created from tubular heaters whose heating part is immerged directly into the liquid.
Some examples of applications of this product are kettles, washing machines, steam generators, fryers, hydraulic control units, cooling towers and all uses where there is the need of heating a liquid.
Since they can be employed for a lot of applications, there are different types of immersion heaters and usually there is the possibility to choose among different options for every use. Also installations methods are different and they have to be considered during the choice of a product, together with the covering material of the tubular heater and the type of joint (mainly threaded plug or flange) and the different relationships between power and element surface (specific charge) etc.
The heat transmission of the tubular heating element to the environment typically very efficient. That is why there are not problems of overheating or degradation of the electric conductor.
Rather can appear problems related to the corrosive effects of the environment. Among the different causes: inadequate knowing of the liquid composition, unusual solicitation of the tubular heater, sedimentation of contaminating substances, difference of the elements materials from which is made the heater (resistance, flange and filler metal). All these elements could cause corrosion.
Materials of the electric heaters for liquids
ELMITI offers a big range of electric heaters in different materials. The material is chosen according to the intended use of the heater.
The materials used for the heaters for air, as normal steel, stainless steel and Incoloy800 can be used also for the heating of liquids.
The use of normal steel in the covering of the heaters for liquids is limited when there is the need of heating oil and for closed water systems, where corrosion cannot damage the steel surface. In these cases steel is a good solution, thanks to its cheap price.
Stainless steel AISI 321, which we usually use, is really good for some heating applications for liquids, for examples for defrosting, in washing machines and dishwashers and in not aggressive liquid food.
Incoloy 800 is suitable for high temperatures but also for covering heaters used in environments subject to corrosion, for example for heating hard waters which contains a big quantity of calcium.
With a suitable alloy there is the possibility to improve the resistance of the heater towards corrosion of the normal steel. An efficient substance is the molybdenum, which increase the strength of stainless steels against corrosion, for example in reducing liquids which contains chloride. In these cases the quality of the used steel is AISI 316L, resistant against acids and suitable as covering material for electric heaters for liquids in different fields.