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Nordson Xaloy has launched a heater ‘coating’ which could take the place of heater bands for injection barrels, nozzles and melt pipes. The product is designed to maintain melt uniformity in extrusion melt pipes and adapters, and eliminate downtime for removing melt ‘blowback’ from injection nozzles.
Initially, the ‘SmartHeat’ coating was introduced specifically for injection barrels, but has since been adapted for nozzles. The coating can simplify maintenance and prevent the downtime caused by molten polymer oozing backwards (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, claims Nordson.
In addition, the product has been used on melt pipes 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. Nordson states that replacing band heaters with the continuous coating of the SmartHeat system ensures a consistent temperature over extended lengths.
Paragon Films, a processor based in the US, chose SmartHeat technology mainly to ensure uniform temperature control throughout its melt pipes. Gary Greenfield, Director of Engineering at Paragon Films said: “Anyone utilising band heaters knows the issues you can have with inconsistent heat transfer and the problems encountered when heater bands go bad,” said Greenfield. “We believe SmartHeat will eliminate these problems, not only providing a more reliable solution than band heaters but helping to reduce energy use as well.”
The SmartHeat system consists of two layers of plasma-sprayed metallised 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, Nordson claims that 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 is said to virtually eliminate heat losses to the workplace, saving on air conditioning costs and reducing the risk of operator injury.
“The SmartHeat system is 25 to 60% more energy-efficient than band heaters, and as a continuous coating it distributes heat more uniformly — a crucial advantage for any melt pipe or barrel,” said David Hotchkiss, Global Product Manager for Nordson Xaloy. “Since all SmartHeat wiring is run underneath the thermal insulation, it eliminates the hazard of having numerous exposed wires connected to multiple heater bands.”