The Kadant Blog

Turbulator® Tube™ Bars: Heat Transfer Rate and Uniformity

Turbulator Tube bars provide significant improvement in both the heat transfer rate and heat transfer uniformity from dryers with rimming condensate. Turbulator Tube bars are stainless steel axial bars, installed on the inside of dryers or rolls to increase heat transfer rates through the shell by inducing resonant turbulence in the rimming condensate film. The increased heat transfer rate is also more uniform in the cross-machine direction than any other internal dryer configuration. These features can be used in dryers with rimming condensate to:

  • Increase drying rates of paper machines that are already running at the steam pressure limits
  • Improve moisture profile on machines that have poor heat transfer uniformity
  • Increase rate of response to changes in steam pressure
  • Improve machine runnability, reduce edge cockles, edge cracks, and sheet picking
  • Reduce time required to thread and widen the sheet

Optimizing heat transfer

Kadant Johnson conducted exhaustive testing in its Research Center to determine the optimum configuration for its dryer bars. The heat transfer rate depends on several factors, such as speed, condensing load, steam pressure, syphon location, syphon clearance, and number and configuration of dryer bars. A high rate of heat transfer can be maintained, even at high dryer speeds, if the syphon clearance is optimized.

In general, the highest heat transfer performance occurs when the syphon clearance is set near the optimum values.

What can you expect from Turbulator bars?

  • Increased drying capacity
  • Improved moisture profile
  • Increased potential for electrical power production
  • Quick installation time
  • Reduce potential for bar corrosion
  • Reduce sheet breaks with more uniform dryer surface
  • Reduced steam pressure
  • Reduced torque power to rim
  • Reduce speed to rim
  • Efficient steam use
  • Written by:
    Danielle Rohrer

    Danielle Rohrer

    Director Marketing, Kadant Inc.

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