Immersion heaters are widely used in many industries to aid in the manufacturing, processing and heating of many products like food, oil, water and chemicals. They consist of tubular or huge heating elements, which are immersed in the liquid before the heating starts. Engineers and industrialists consider these contraptions very effective and efficient because the entire heat energy that is generated is dispersed directly into the source without dissipating it.
The sheath material, which is the actual heating element, is chosen carefully and accordingly to the product that needs to be heated. If care and caution are not used while selecting the right casing, you may end up damaging both the product and the heater itself.