L&W Felt Permeability Meter

Optimize the press section with industry-leading permeability measurement

Accurate measurement of felt status is imperative for not only a cost-effective and efficient felt conditioning program, but also for maximizing machine runnability—and profitability. 

L&W Felt Permeability Meter provides paper mills, felt and chemical suppliers industry-standard results for felt permeability measurement. By measuring the water permeability of the felts, clogging and wear are easily discovered and the potential to optimize conditioning, dewatering, as well as paper quality is possible. As a result, suppliers can provide more precise recommendations and paper mills can extend and optimize performance.



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Felt Permeability uncovers:

  • Felt compation due to press conditions

  • Felt wear

  • Shower performance (HP, Chemical, Lube, etc.)

  • Chemical cleaning program optimization 

  • Tradeline distortion

  • New felt design opportunities

Did you know that a 1% increase of the dry content in the press section = 4% reduction in energy use in the dryer section?

The instrument measures felt length, provides measurement positions in relation to the machine width and includes position detection in both the machine and cross direction (MD and CD). Plus, it captures the water flow with a very narrow beam providing the smallest felt condition details for further analysis. 


  • Dual purpose: In online scanners and for handheld use
  • Enhanced safety and ease-of-use features available for both manual testing and online scanner operation (keyless start/stop)
  • Intuitive software user interface provides:
    - MD/CD profiles for regular inspections 
    - 2D and 3D-data mapping to safely and easily visualize problem areas
    - Graphical Fast Fourier Transformation (FFT) finds peaks that appear at certain frequencies


  • Overcomes high energy costs in the dryer section 
  • Improves planning for shutdowns, while also reducing unplanned ones
  • Helps maximize machine speed 
  • Optimizes felt conditioning with optimum levels of vacuum, chemical dosage, and high pressure water 
  • Helps achieve the best overall felt lifecycle performance 
  • Improves paper quality and reduces sheet breaks
  • Enables more informed troubleshooting

Obtain a finer data point by pairing with L&W Felt Moisture Meter

One measurement alone doesn’t tell you the complete story; it tells you the part of it.

Permeability dip and moisture peak indicates clogging issue

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