Precision Line-scanning vs. Standard IR Imaging
PROdry Technology offers the world's most sophisticated infrared imaging service for analyzing problems with papermaking equipment. PROdry's unique "Precision Linescan Infrared Imaging" (PIR) utilizes a high-speed infrared scanner to capture even the smallest thermal variations on operating equipment or the moving paper web. Compared to "standard" TV-like infrared imaging, PROdry's technology provides detailed time-based information to discern machine-direction thermal problems which are otherwise poorly defined. This in turn allows PROdry engineers to accurately evaluate the paper machine operation and equipment condition and ultimately discover sources of unwanted thermal variation.

Example 1 serves to illustrate the added value of PROdry's PIR technology in accurately diagnosing operating problems. The tissue machine in question was displaying a poor reel moisture profile with well-defined moisture streaks at the edges and center of the reel. Attention had been focused on the felt and felt cleaning as the probable sources of these streaks. The "standard" infrared image of the reel shown below is a full-frame picture of the reel. The wet edges and center streak are visible as cooler bands, and appear to be continuous in the machine direction.

However, using line-scanned PIR technology to uncover machine-direction thermal variation, it becomes clear that the front and center wet streaks are not constant at all, but rather are periodic in nature. The PIR image of the reel clearly shows the cold "spots" that make up these major streaks. The back wet area in fact appears to be truly continuous. A graph of machine direction temperature shows the MD detail provided by line-scanning the reel. Relating the scanning frequency to the machine speed, one can calculate the exact period for a Yankee dryer rotation, as indicated on the figure. The reel displays four cold spots for each dryer revolution, matching the number of condensate pickup headers in the Yankee. As a result of this information, the mill's attention was drawn to the Yankee internals and the steam system operation to reduce the impact of the center and front wet streaks and improve the reel moisture profile.