Four main types of heaters in Plastic Extruders

　　(1) mica heating ring, heating body is heating wire or flat heat wire (resistance band). The insulating layer of the screen changer is made of mica sheet. The coil sheath is made of ordinary carbon steel.

　　The advantages of mica heating ring are simple structure, easy to replace and fast heating speed. The shortcoming is that the life is short. This type is widely used in early extruders.

　　The port life of the mica heating ring is related to the temperature. The higher the temperature, the longer the life is. The main reason is that the mica has poor heat dissipation capacity. The air gap formed between the shell of heating ring and the machine is also the screen of heat dissipation. So the electric wire is easy to burn. In addition, the mica layer absorbs moisture after cooling, resulting in arcing and fusing of adjacent electric heating wires.

　　(2) the cast aluminum heater of screen changer : the Zhengzhou batte Machinery Co., Ltd. effectively uses the electric heating rod in the form of bending the electric heating rod according to the strange shape, casting in the aluminum alloy, forming the cast aluminum heater. In addition to the advantages of the general resistance heater, the cast aluminum heater can be made into a body that fits perfectly with the barrel. The air gap is very small, which is beneficial to the heat conduction of the sub heater. The cast aluminum heater is lower in cost and longer in life than the mica heating ring. The electric heating rod is tightly fixed in the cast aluminum shell to improve the heat conduction performance. The vibration, moisture proof and explosion proof characteristics of the heating wire are enhanced. For the occasion where cooling is needed, the cooling coil can be cast into the cast aluminum heater. Therefore, this type of heater is widely used.

　　(3) aluminum shell heater. The aluminum shell heater is made of straight electric rod as heating element and inserted into the aluminum shell hole. After the electric rod is damaged, it can be replaced simply, and the maintenance cost is reduced. The disadvantage is that heat transfer and vibration resistance are not as good as cast aluminum heaters.

　　(4) a ceramic heater, an electric heating wire heater with ceramic blocks instead of mica as insulation, has the advantages of fast heating, long life, easy replacement and adjustment of the heater capacity, and more and more applications have been obtained.