Product/Service Company Name Brand CAD Drawings Industrial Web White Papers More News Forums

Guides Home | Plant & Facility Equipment

Industrial Electric Heating Methods

In many industrial manufacturing processes, a product requires heat formation or curing. However, because various materials respond to heat in distinct manners, there are several unique heating methods that may be appropriate for a given application. Electric heating is a common choice for many manufacturers because it is clean, relatively quiet, and efficient. Electric heat controlled methods can achieve a precise temperature quickly, maximizing the production process. However, they can often be more expensive than basic fuel upfront, but may save money in the long-term due to overall gains in process efficiency and production time. Several industrial electric heating methods are available, including resistance heating, electric arc heating induction heating, and dielectric heating.

Resistance Heating

By definition, electric heaters convert electric energy into heat. The process, however, can vary significantly between methods. In resistance heating, an electrical current is passed through a resistive material, which results in heat. A basic resistance heater consists of several resistant wire coils housed in a protective metal shell, which function as a conductive heat source. A resistance heater can be immersed, stand alone, or be used in conjunction with a heat pump. The amount of heat generated is contingent upon the amount of current applied. Resistance heaters are commonly used in process heating, to raise the temperature of a given product through the transfer of heat. They can also be used in melting and fusing processes.

Electric Arc Heating

Electric arc heating is an effective material heating method, especially in applications involving steel. Electric arc furnaces can be configured in a variety of ways, but all depend on the creation of a strong electric arc. To create this electric arc, an electrode (for example, carbon) and a complimentary material (such as graphite) are placed in close proximity, with the material to be melted placed in between. When a current is applied and the electrode touches the metal, a strong electric arc is created which causes the metallic material to melt. After contact is made and the arc is generated, the electrode is slightly removed so as to better control the process. Because electric arc furnaces can reach temperatures up to 3, 500 degrees Fahrenheit, they are effective at melting heavy metals such as steel. Time-rate adjusting controllers are often used to ensure that the temperature of the furnace maintains the required application temperature.

Induction Heating

Induction heating is extremely fast and precise. To produce heat through induction heating, alternating current is applied to a wire coil. The wire coil is wound around an insulated container, which houses the soon-to-be-heated material. When a high-frequency current is applied, the coils develop a magnetic field, and the material inside the insulated container (if it is magnetic) subsequently undergoes a shift in magnetic field. The result is a change in the material’s molecules position, generating friction and heat. If the material in the container is non-magnetic, the magnetic field generated by the coil will not affect the material. Instead, the carbon is substituted for the container material because it reacts to the coils’ magnetic field, and the resulting heat warms the container contents via conduction.

Dielectric Heating

With nonconductive materials, inductive heating doesn’t work. Dielectric heating, however, is an effective way to heat non-conductive materials. Two metal electrodes are placed on either side of the nonconductive material, much like in a basic capacitor. Next, high-frequency current is applied to each electrode, which distorts the material in between. As the frequency increases, distortion increases, creating friction. Friction results in heat, which then spreads throughout the nonconductive material. Dielectric heating is a common method for heating and bonding plastic.

Other Plant & Facility Equipment Guides