In this article we gonna see few around 6 types / methods of electric heating :
(1) Electron Bombardment Heating Method :
what is electron bombardment heating ?
- Electrons are bombarded on particular job and electric heating is produced. For highly accelerated electrons, the high D.C. voltage is required.
- This high D.C. voltage is connected to the anode and the object ‘Which is to be heated is anode at cathode.
- The electrons are bombarded i.e. emitted from anode. These negative charged electrons are attracted towards cathode.
- The cathode is heated because of the of bombardment electrons.
(2) Resistance Heating Methods :
what is the resistance heating methods?
(a) Direct resistance heating
- The electric current is made to pass through the substance to be heated or charge itself.
- The electric current while passing through the charge produces I2R loss which appears in the of the heat thus, charge is heated up.
- Few examples Of this heating method: are resistance welding, electrode boiler for heating water, salt bath furnace. This is called as direct resistance heating.
(b) Indirect resistance heating
- Current is passed through heating element and I2R loss is produced which appears in the form of heat.
- This heat is passed on to the substance or charge to be heated by radiation and convection. This is called as indirect resistance heating. For example room heater, soldering iron, hot plate water heater, electric oven, hair dryer, frying pan etc.
(3) Arc Heating Methods :
what is Arc Heating Methods ?
Arc heating : The heat energy of arc produced by electric means is utilized for heating the substance or charge. The arc temperature is about 3000 to 35000 C .
(a) Direct arc heating
An arc is made to struck between electrode and charge itself. The heat energy Of arc is absorbed by the charge and thus heating is done. This is called as direct arc heating.
(b) Indirect arc heating
An arc is made to struck between two electrodes. The heat Of arc is then passed on to the charge through radiation. This is called as indirect arc heating.
(4) Radiant or Infrared Heating
what is Radiant or Infrared Heating ?
heat energy from an electric lamp is focused on the charge to be heated. The heat energy is transferred through electromagnetic radiation. This is called as infrared heating. This is used drying the paint in vehicle industries and different metallic bodies like steel furniture.
(5) Dielectric Heating
what is Dielectric Heating ?
- In this method of electric heating use of dielectric losses is made to heat the non-metallic materials.
- Non-metallic material to be heated is placed between two metal electrodes across which a high voltage having high frequency is applied, the heat is developed owing to the dielectric losses taking place.
(6) Short, Direct and Indirect Induction heating
Direct induction heating –
- In this method Of heating the current is induced by electromagnetic action in the body to be heated.
- The induced currents when flowing through the resistance of the body to be heated develop the heat and thus raise the temperature.
- In induction furnace heat is used to melt the charge and eddy current heaters used for heat treatrnent of metals are other forms of direct induction heating.
Indirect induction heating –
- In this method Of electric heating the eddy currents are induced in the heating element by electromagnetic action.
- Eddy currents set up the heating element produce the heat which is transferred to the body to be located up, by radiation and convection.
- Certain ovens used for heat treatment of metals work on this principle.
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