The Basics – The three main modes of heat transfer are:
Conduction- When two bodies of different temperatures are brought in contact with each other, heat energy flows from the hotter to the colder body. A directly heated product could be either touching the heater or through a secondary physical sub straight that the heater is fixed to or within i.e. a mould tool. If you are heating a product or process directly, you will need to carefully consider the power requirements of the element and what style of element is best suited to your chosen application.
For example an oil bath heater may be best suited towards tubular immersion heaters, but making sure that the sheath of the heater doesn’t overheat the oil and cause carbonisation of the oils on the sheath of the heater, always try to keep the sheath temperature as low as possible and in a controlled condition.
Convection- Heat energy is transferred from a higher temperature region into a gas or liquid to a lower temperature region as a result of movement of masses within the fluid of gas.
The agitation /stirring of both gasses and liquid helps to transport the heat generated by the heater to the product quicker and more efficiently, specialist process heater for both gases and liquids are available from both ourselves and from our US partners Tempco.
Radiation- Infrared radiant energy is transported through Air or space by electromagnetic waves without the need for conductive media. Consequently, heat can be delivered in concentrated areas at increase rates, many processes such as drying, curing of paints, baking thermoforming of plastic materials and the drying of paper and pulp are to name but a few that use Infrared heating within the process.
Electromagnetic can be further broken down into the following four categories:
4. Radio frequency/Induction