Monitoring Heat Control when Manufacturing Fiberglass Insulation
Banaszkiewicz is plant engineer at CertainTeed Insulation Canada Inc., an Ottawa manufacturer of fiberglass insulation for industrial, commercial and residential use. To produce the insulation, it is necessary to melt glass, of which 80 percent is recycled. The process requires temperatures ranging from 1,652 to 2,192°F (900 to 1,200°C).
Before melting, ingredients are added, and the molten glass flows from the furnace to the forehearth and finally into the bushing. Eventually, the molten glass drops down though an orifice in the channel to a centrifugal spinner. The glass is forced through the spinner's tiny holes and comes out as glass fiber. But the heat is still on and the complex process is not over yet.
In the next step, the glass fiber is formed and collected on a conveyor, where polymers are added to keep it together. From there, it goes to the curing oven where the additives harden. The fiber then gets cut and sliced, Banaszkiewicz says.
To control the fiber's quality throughout the manufacturing process, it is important to control the temperature in the electric forehearth, which is done by increasing or decreasing the power, according to Banaszkiewicz. Based on the temperature of the glass in each zone, power adjustments are made to each forehearth zone.
The need to measure the temperatures in the glass-fiber manufacturing process led Banaszkiewicz to Rayek's Marathon FA1G sensor, a fiber-optic infrared thermometer for measuring glass temperatures from 1,382 to 3,047°F (750 to 1,675°C). With applications ranging from measuring molten glass in the forehearth to measuring the packing-material temperature for optimum regenerator airflow control, the FA1G thermometer was a fit with CertainTeed's needs.
Installed in 1996, the system of Raytek FA1G sensors has provided a wide variety of measurements in many locations, Banaszkiewicz says. "We measure the temperature of the glass through the holes on top of the forehearth, so the sensor can actually see the glass," he says.
Prior to installing the FA1G sensors, Banaszkiewicz used platinum thermocouples placed in the glass. Depending on the manufacturing process, the FA1G sensors cost about half that of platinum thermocouples, providing money- and time-saving advantages, according to Raytek.