What are the properties of a good Heating Element?

Heating Element

The device which converts electrical energy into heat energy through the process of Joule heating is known as heating element. The heating element is the part of any electric heating appliance in which the electrical energy transformed into heat. The electric current through the element encounters resistance which results in heating of the element.

Requirements of a Good Heating Element

A good heating element should possess the following properties −

  • High Resistivity

    The specific resistance or resistivity of the material used for making the heating element should be high. When the resistivity of the material is high, then the element will require small length and shall give convenient size.

  • High Melting Point

    The melting point of the material used for making the heating element should be sufficiently higher than its operating temperature. Otherwise, a small increase in the operating voltage and hence in the operating temperature will destroy the heating element.

  • Low Temperature Coefficient of Resistance

    As the resistance of a conductor varies with the temperature and this variation should be small in case of a heating element. Otherwise, when switched on from temperature to go up to say 1500 °C, the low resistance at the initial stage will draw excessively high currents at the same operating voltage.

  • Positive Temperature Coefficient of Resistance

    The material used for making the heating element must have positive temperature coefficient of resistance. If the temperature coefficient of resistance is negative the elements will draw

  • High Oxidising Temperature

    The oxidising element of the heating element should be higher than its operating temperature. Otherwise, oxidised layers from the surface will flake off changing the resistance of the heating element and giving it a smaller life.

  • High Ductility and Flexibility

    The material used for making heating element should have high ductility and flexibility so that it may have convenient shapes and sizes. The material used for making the heating element must not be brittle and fragile.

  • Sufficient Mechanical Strength

    The material used for the heating element should have the sufficient mechanical strength of its own.

  • Should Withstand Vibrations

    In most industrial processes, quite strong vibrations are produced. Some furnaces have to open or rock while hot. Therefore, the material of the heating element should withstand the vibrations while hot and should not break.

  • Anti-Corrosive

    The material of heating element should be anti-corrosive because in many heat treatment processes, the heating atmosphere is corrosive. Therefore, when exposed to this atmosphere or any other chemical fumes the element should not corrode. Otherwise, its resistance will change and life will shorten.

Updated on: 23-Feb-2022

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