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According to the different electric energy conversion modes, electric heating is usually divided into resistance heating, induction heating, arc heating, electron beam heating, infrared heating and medium heating.

Ohmic heating

The joule effect of a current is used to change electrical energy into heat energy to heat an object. Usually divided into direct resistance heating and indirect resistance heating. The power supply voltage of the former is directly applied to the heated object. When there is a current flowing through the heated object itself, the ironing machine will generate heat electrically. An object that can be heated directly by resistance must be a conductor with a high resistivity. Since the heat is generated from the heated object itself, it is internal heating, and the thermal efficiency is very high. Indirect resistance heating requires heating elements made of special alloy or non-metallic materials, which generate heat energy that is transmitted to the heated object by means of radiation, convection and conduction. As the heated object and heating element are divided into two parts, the type of heated object is generally unlimited and easy to operate. The heating plate

Heated surfaces are bombarded with electrons moving at high speeds in an electric field. The main component of electron beam heating is electron beam generator, also known as electron gun. The electron gun is mainly composed of cathode, poly-beam, anode, electromagnetic lens and deflection coil. The anode is grounded, the cathode is connected to the negative high position, the focusing beam is usually at the same potential with the cathode, and an accelerating electric field is formed between the cathode and the anode. The electrons emitted from the cathode accelerate to a high speed under the action of accelerating electric field, which is focused by electromagnetic lens and controlled by deflection coil, so that the electron beam shoots towards the heated object in a certain direction.

Medium heating is used industrially to heat hot gels, dry grains, paper, wood, and other fibrous materials; Also can be preheated plastic molding, and vulcanization of rubber and wood, plastic, etc. Selecting the appropriate electric field frequency and device can heat only the adhesive glue while heating the plywood without affecting the plywood itself. For homogeneous materials, monolithic heating is possible. The heating plate