Watt-Flex cartridge heaters are warranted removable from bores by their manufacturer, Dalton Electric Heating Co. Inc., because their split-sheath design prevents warping. A video from the company demonstrates how the split-sheath design simplifies heater removal.

Split-sheath construction allows the heater to expand bilaterally when energized for maximum metal-to-metal contact with the bore and maximized heat transfer (conduction) to the surrounding metal, says the company.  The design provides a uniform temperature profile along the entire sheath. If removal by drillout from a properly sized bore is necessary, the Ipswich, Mass.-based company will replace any damaged heaters free of charge.

When de-energized, the heater contracts uniformly to ease removal from the bore. The company says the design eliminates bore seizure, drillout of the heater, damage to the bore, platen repair costs, replacement heater costs, maintenance labor costs and downtime costs.

Click here to see a company-produced video about using the cartridge heaters for process heating.