In North Carolina, a manufacturer of specialty synthetic fibers for both home and industrial applications sought a new custom-designed autoclave for its drying process, and turned to Chromalox, a Pittsburgh company specializing in heat and control.

Rather than using expensive fossil fuel, the drying system uses nitrogen as the heat transfer medium via forced convection with temperatures ranging between 400 and 500°F (204 and 260°C) in the system’s base heat load. In addition, nine individual zones within the system each require its own temperature and power-control loop for precision quality control.

A 35 kW GCHIS circulation heater provides the nitrogen loop’s baseline heating. Chromalox’s fintube tubular heating elements with Incoloy sheaths heat the autoclave’s interior. Individual loops within the system are heated by nine 5 kW CHIS circulation heaters. Each of the loops are controlled by Chromalox MaxPac SCR power controllers, part of the autoclave’s main control panel. MaxPac panels allow precision control of each loop, which utilize high temperatures and low gas flow.

A similar system was designed and retrofitted to an existing autoclave within the customer’s facility. For more information, go to