Energy-efficient coating as alternative to heater bands
An new heating system from Nordson Xaloy replaces conventional heater bands with a highly energy-efficient heater coating for maintaining melt uniformity in extrusion melt pipes and adapters, and eliminating downtime for removing melt “blowback” from injection nozzles, the company announced.
Introduced as an injection barrel coating, the so-called SmartHeat system has since been successfully adapted for these additional uses:
? Injection nozzles. A SmartHeat coating can simplify maintenance and prevent downtime caused by blowback, the backward oozing of molten polymer (particularly when the seal is not tight) into the spaces between the heater bands and the nozzle. Available on new nozzles or as a retrofit, the coating is easily cleaned without need to stop production.
? Melt pipe or adapters. These components for transferring molten polymer from the extruder to downstream equipment can cover considerable distance, making it difficult to maintain melt uniformity. Replacing band heaters with the continuous coating of the SmartHeat system ensures a consistent temperature over extended lengths.
The SmartHeat system consists of two layers of plasma-sprayed metallized ceramic with a nichrome wire wrap sandwiched in between, plus a thermal insulation cover. Because the heat from the wires is conducted throughout the ceramic material, the system raises the temperature of a machine component to target levels more quickly than with band heaters, maintains it more uniformly, and uses less energy. The tightly strapped thermal insulation wrap over the ceramic coating virtually eliminates heat losses to the workplace, saving on air conditioning costs and reducing the risk of operator injury.
Injection nozzles with SmartHeat coating (photo: Nordson)