The Concept

The objective of the felt/fourdrinier fabric conditioning system is to improve the overall fabric efficiency. The system can use either mechanical or chemical cleaning or a combination of both depending upon the conditions.

The major problems are that

  • All raw materials and additions used in paper making are potential fillers, specially with waste and secondary fibre stock.
  • Mills with closed systems add more contaminants causing problems in felt/fabric operation
  • Frequent use of wet end starch, wet strength resins and various synthetic retention-aid polymers have increased the felt/ fourdrinier fabric filling problems

To combat these problems the paper makers need more than just showers and suction boxes. Mechanical cleaning and c onditioning of the felts/fourdrinier fabric is attained through three methods.

  • High pressure showers (essential)
  • Low Pressure flooding showers (recommended)
  • Full width suctior) boxes (essential)

Low pressure flooding showers provide the flushing media for removing contaminants. Usually located on the inside of the felt/fourdrinier fabric, it is more effective when positioned in the nip formed by the felt/fourdrinier fabric and the felt/ fourdrinier rolls. A hydraulic wedge action thus created, forces the water through the fabric, flushing out the filling materials. Oscillating high pressure showers with needle nozzles are the most efficient means of cleaning available today. With proper positioning and technologically improved “No dwell time” synchronised oscillators, these showers provide Complete Coverage Cleaning.

Though these showers are more expensive than the conventional air and water cylinder and the crank arm oscillating types, their vastly superior performance and the benefits to be gained from them far offsets the initial higher expenditure. They are:

  • Maximum cleaning and increase in bulk
  • Minimum water consumption
  • Minimum felt/fourdrinier fabric damage
  • Minimum shower maintenance
  • Minimum energy requirements

For optimum operation

  • Place a high pressure shower with needle nozzle 250-400 mm from the fabric
  • Use continuous or intermittent showering depending on requirements
  • Normally, position the show r against the paper side
  • Most suitable nozzle diameter is 1.0 mm
  • Water temperature should be equal to the temperature of the felt/fourdrinier fabric being cleaned
  • Jet angle should be adjusted to suit individual application (start at 90 degrees, then experiment with or against the run by a few degrees)
Shower Chart
  1. Headbox Showers (Rotary & Swing)
  2. Backsilce Shower
  3. Breast Roll Showers
  4. Dandy Roll Shower
  5. Suction Couch Shower
  6. Forward Drive & Wire Return Knock Off  Showers
  7. Wire Return & Trim Knock Off  Showers
  8. Wire Return Roll Showers
  9. Wire Cleaning H.P. Shower
  10. Felt Conditioning H.P. Showers
  11. Felt Washing Showers
  12. Vacuum Box Lubricating Showers 
  13. Grooved Press Cleaning Shower 
  14. Mould Cleaning H.P. Shower
  15. Extractor Roll H. P. Shower
  16. Felt Conditioning H. P. Showers
  17. Felt Washing Showers
  18. Felt Sluicing Showers
  19.  Felt Washing Showers
  20. Dryer Screen Conditioning Showers