Coil heaters are high performance mini tubular heaters that have small rectangular, square or round cross sections that are flexible and can acquire different shapes and configurations.
The sheath material of standard cable heaters is stainless 304; their heating core is coiled or straight solid Nickel Chrome wire. Cable heaters can transmit up to 35 W/in2 heating capacity and can attain up to 15000F surface temperature.
Cable heaters could be coiled, to form coil heaters that are ideal whenever a large amount of heat is required in a confined space. Coil heaters have many applications but are mostly utilized as powerful heating cells inside hot runner nozzles in plastic injection molding.
Coil and cable heaters can accommodate “J” type or “K” type thermocouple sensors that could be placed internally at the tip or the middle of a heater. They can be made as well to have profiled or distributed wattage configuration.
The fine electrical terminals and thermocouple wires are attached to power and thermocouple leads inside a transition adapter which has a larger diameter than the actual heater’s cross-sectional diameter.
Although coil heaters and cable heaters are fully annealed and can acquire any shape, they should be formed to a final shape in a single attempt. Forming and bending operations harden the outside stainless shell of a heater, and re-annealing might become necessary if changing the form is required.
COIL HEATER CROSS-SECTIONS |
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Round | 0.125″ |
Square | 0.130″ x 0.130″ |
Rectangular | 0.090″ x 0.145″ |
HOT RUNNER NOZZZLES
CUTTING AND SEALING BARS
MEDICAL EQUIPMENT
ROD, PIPE AND TUBE HEATING
HEAT TRACING
SEMICONDUCTOR MANUFACTURING
Plain leads with high temperature sleeve
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Stainless steel braid
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Stainless steel armor
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The inside diameter of a coil heater is 0.020″ smaller than the nominal diameter of a nozzle. This is done intentionally to secure a positive grip at all times. During installation, a coil heater should be screwed to its proper position. Pushing forcefully or slightly opening the coil to facilitate installation could permanently damage the heater.
During installation, only the straight cold section can be slightly bent. This should be done in a single attempt. The bending radius shouldn’t be less than 0.5″. It is always recommended to contact our factory when modifications of form are required.
The straight cold section can withstand temperatures of up to 1500°F. However, to protect the lead wires, the temperature of a section beyond the transition adapter should be maintained below 480°F.
Usually the sensing tip of a thermocouple is located at the end of the last loop of a coil heater. Care should be taken to insure that the last loop is properly gripping the nozzle.