Application of Dielectric Heating
Dielectric heating is suitable for following industrial applications :
- Gluing, curing and drying of wood.
- Preheating plastic perform to condition them for moulding.
- Plastic sewing.
- Drying and heat treatment of natural and synthetic rubber, rayon, nylon, etc.
- Processing of chemicals during manufacture. Curing of sand cores in foundaries.
- Sterilization of medical supplies.
- In food processing industry for following functions :
- Pasteurising milk and beer inside the bottles.
- Dehydrating fruits, vegetables, eggs, etc.
- Cooking foods without removing the outer shells.
- Defrosting frozen foods in large bakeries.
- Disinfecting cereals and grains, etc.
These applications are explained in detail in the following subsections.
Preheating of Plastic Performs :
- The thermosetting plastics should be heated to a particular temperature for the purpose of hardening or setting.
- This process is called as curing.
- Plastic perform is the raw plastic in the form of tablets or biscuits. It is first put in the hot mould.
- These performs are heated uniformly throughout the mass to the desired temperature by means of dielectric heating.
Gluing of Wood :
- The wooden furniture items such as table tops, desk tops etc. are prepared by gluing boards together.
- The animal glue is used traditionally for this purpose. But the problem with this glue is that it needs a longer curing time (typically 24 hours).
- We can use the dielectric heating for drying the glue which does it in just 30 seconds and ensures a strong bond.
Sewing of Plastic Films :
- Articles such as rain coats, umbrellas etc. are made from the plastic films with the help of electronic sewing machine operating on the principle of dielectric heating.
- The ordinary sewing technique will make the article weak and it will not be air tight or water tight. and
- But the use of dielectric heating ensures that the strength remains intact and becomes water proof.
Food Processing :
With the help of dielectric heating it is possible to heat the food inside cartoons or wrappings.
Following are the applications related to the food processing using dielectric heating :
- Pasteurisation of milk and beer.
- Defrostation of frozen foods.
- Sterilization of foods and medicines.
- Disinfection of grains inside the package.
- Dehydration of vegetables, eggs and fruits.
Diathermy :
- Dielectric heating is used for treating certain types of pains and diseases.
- It is used for heating the tissues and bones of the body.
- In the event of surgery, the diathermy is used to seal the bleeding veins.
Other Applications :
- In the textile industry.
- Rubber industry for heat treatment of rubber.
- In chemical industry.
- In the foundries.