IR camera sees slag

Westar Energy (Topeka, KS, USA;www.sr.com) needed to monitor for slag problems in boilers that drive three 800-MW generators at its St. Marys, KS, USA, electric-generating plant. Traditionally, operators would wear protective visors to see through inspection ports for signs of slag buildup. "That's typical practice in the utility industry, and we make multiple inspections per day," says Carl Schultz, senior PdM analyst for thermography at Westar.

Westar selected the portable, dual-range MikroScan 7400 camera from Mikron Infrared (Hancock, MI, USA;www.mikroninst.com), which offers three selectable termperature ranges, including a high-temperature (400°C-1600°C) range needed for IR imaging inside the boilers where temperatures can exceed 1100°C. IR filtering allows dual-spectral-band operation-8- to 14-μm long-wavelength mode or mid-wavelength with 3.9-μm microfilter for through-the-flame imaging. "This lets us use the camera for predictive maintenance monitoring in the long-wavelength band in the ambient to 400°F range," says Schultz. "Then we can switch to the 3.9-μm band and high-temperature range to image the boiler tubes."