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Introduction Coil Heater
Heating coil is usually designed as two side by side heating coils embedded in the stainless steel tube filled with magnesium oxide and magnesium oxide is a combination of relatively high resistance and good thermal conductivity of the material. If the coil heater circular cross-section and the nozzle surface contacts helix, heat transfer occurs mainly through thermal radiation. Because of this, the heating surface heat flux density limited to 0.3W / c㎡.

Heating coil of rectangular cross-section or flat oval, with the nozzle has a larger contact surface that allows part of the conduction heat transfer. This reduces the thermal load and improve the thermal equilibrium, using 6-15W / c㎡ heat flux density.

Heater start is no heating zone, this coupling region has at least 55mm of pipe length. At the heater end of the nozzle surface near is installed the thermocouple location, and a short unheated area is 10-15mm.

Increase or decrease the coil winding pitch, the most common type of wound is logarithmic winding. In the hot runner nozzle contact with the mold parts, such as the support surface and the end surface is provided with strong heating. Therefore, the thermal characteristics of each heater for nozzle, so should not differ heater varieties instead.

The coil heater also has applications heating pipe, it made in the ring constraints, outside with stainless steel armor. Copper tube make the heater to a nozzle heat transfer is uniform, but also improves the heater's "dead" end of the nozzle heating, but also covers the thermal radiation of outward. Especially for high temperature operation and good durability, this design improves the uniformity of temperature distribution in the nozzle. These heaters allow heat density reaches 15W / c㎡.

Coil heater casting in the copper alloy sets or pieces, which is characterized by maximum durability and allow the heat load.

Band type coil heater wound in a spiral heating tube, small diameter 1,8mm, or flat 1.3mmX2.3mm, mainly used in the nozzle supporting surface.

When the nozzle spacing is made smaller, tend to recommend enhanced small-diameter coil heater. New development coil heater began successfully used in low pressure heaters. 5V and 230V heater durability can be compared.