Smooth Bore Dryer
Example 6 illustrates the use of high-speed line scan thermal imaging to address problems in smooth-bore Yankee dryers. These older-design cylinders continue to operate productively in many paper machines around the world. With less sophisticated steam delivery and condensate removal systems than their ribbed counterparts, they are nonetheless susceptible to operating problems that impact the machine's runnability and mill's profitability. In this example, the thermal distribution of a smooth-bore Yankee is shown for one dryer revolution in the rainbow palette. Problems evident in this case include a wet front edge with a compounding low spot on the shell, a dry back edge, and two hot spots resulting from the steam delivery system in the Yankee. The two full-width condensate "scoop" pickups can be easily identified. Internal adjustments were made to the pickups to reduce the cross-machine variation in temperature.

	Example 6: Smooth-bore Yankee dryer thermal map showing internal pickup points, hot spots caused by steam injection, and surface irregularity on front edge. (“Rainbow” palette)
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© 2007 PROdry Technology, Inc. Site last updated 3/7/07