Four Kinds of Heaters Commonly Used in Plastic Extruders

Four kinds of heaters are often used in plastic extruders. Here is a brief introduction to their working principles, advantages and disadvantages.

(1) Mica heating ring, the heating body is electric heating wire or flat electric heating wire (resistance band). The insulating layer is made of mica sheet. The ring-shaped protective shell is made of ordinary carbon steel plate.

The mica heating ring has the advantages of simple structure, easy replacement and fast heating speed. The disadvantage is short service life. This type was widely used in early extruders.

The life of mica heating ring is related to temperature. The higher the temperature, the shorter the life. The main reason is the poor heat dissipation ability of mica. The air gap formed between the shell of the heating ring and the machine is also the shield of heat dissipation. Therefore, the electric heating wire is easy to dry burn. In addition, the mica layer absorbs moisture after cooling, resulting in arcing and fusing of adjacent electric heating wires.

(2) Cast aluminum heater: The way to effectively use the electric heating rod is to bend the electric heating rod into shape according to the shape of the change, and cast it into the aluminum alloy to form the cast aluminum heater. In addition to the advantages of general resistance heater, cast aluminum heater can be made into a shape that is very consistent with the barrel, and the air gap between them is very small, which is conducive to heat conduction. Cast aluminum heater has lower cost and longer service life than mica heating ring. The electric heating rod is tightly fixed in the cast aluminum shell, improving the heat conductivity. The anti-vibration, anti-gasification, moisture-proof and explosion-proof characteristics of the electric heating wire are enhanced. For occasions requiring cooling, cooling coils can be cast in the cast aluminum heater at intervals. Therefore, this type of heater is widely used.

(3) The aluminum shell heater uses a straight electric heating rod as the heating element and is inserted in the hole of the aluminum shell. After the electric heating rod is damaged, it can be replaced by a single one, reducing the maintenance cost. The disadvantage is that the heat transfer and anti-vibration performance are not as good as the cast aluminum heater.

(4)Ceramic heater, which uses ceramic block instead of mica as insulating material, has the advantages of fast heating speed, long service life, complete price, easy replacement and adjustment of heater capacity, and has gained more and more applications.

Jiangsu Xinrongplas Machinery Co.,Ltd focus on manufacturing various plastic pipe extrusion machine such as PPR pipe extrusion machine, PVC pipe extrusion machine, PE pipe extrusion machine etc, welcome to consult.