Advancement In Press Felt Technologies, A Paper Makers Need

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Advancement In Press Felt Technologies,A
Paper Makers Need
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PRADEEP MATHUR VlSHAL GARG

• Voith Paper Fabrics, Faridabad
• Tel. [phone]
• Fax. [phone]
• E-mail pradeep.mathur_at_voith.com
• vishal.garg_at_ voith.com
• Website www.voithpaperfabricsindia.com

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Agenda

• Market demand Paper makers need
• Press felt designs
• Developments and its advantages

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Changing Market Requirements

• Sheet grammages are reducing
• Decreasing fibre length
• Paper machines are becoming wider faster
• Shoe presses with longer dwell time increased
  mark potential
• Improvements in fabric life potential
• Easier to clean fabrics

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Press Fabrics Requirements

• Dewatering of the paper sheet
• Water transport to uhle box (partially)

• Even pressure distribution (CD-profile, paper
  surface)
• Sheet transfer through press section

Total Pressure Mechanical Pressure Hydraulic
Pressure
Paper
Felt
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Press Fabrics Requirements

• Water handling capacity
• Running time
• Dimensionaly Stable
• High Dryness
• Recycled Fiber usage
• Even CD-Profile

• High void volume
• Low compaction
• Temperature resistance
• Low dewatering resistance
• Easy cleanability
• No marking

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Paper Makers need

• Provide adequate protection to the sheet to
  travel undamaged through the press
• Ability to Allow Good Water Removal from the Nip
• Good Sheet Control Sheet Separation
• Quick start-up
• Mark free surface
• Retained properties through the life

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Press Fabrics Influence on Paper
QualityDewatering / Dryness
Uhle box

• Slow machines with high uhle box-dewatering
• Press fabrics with high volume and water
  capacity
• Open structure for high dewatering at uhle box
• Problem Re-wetting and splashing

Dewatering
Nip
PM speed
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Press Fabrics Influence on Paper
QualityDewatering / Dryness

• Fast machines with high nip-dewatering
• Light fabric with reduced flow resistance.
• Fine batt for higher fabric-saturation within the
  nip
• Problem water removal within the nip, splashing
  at high basis weight

Ecoflow tray (l/min)
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Perfect Press Fabric
Sheet Pickup
Resilience
Dryness
No marking
A Perfect Press Fabric
No rewetting
Dewatering
Stability
Improved Life
Easy to clean
Profiles
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Press Felt Manufacturing
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Press Fabrics Terms Condition

• Warp Cross machine direction yarn
• Weft Machine direction yarn
• Base fabric Load bearing substructure of fabric
• Batt fiber Compressible surface material
• Dtex Weight of 10.000m of the batt fiber
• Permeability Air passage through the structure
  (cfm)
• Void volume Storage capacity ml/m²
• Caliper Caliper mm
• Batt /Base ratio Ratio of batt/base distribution
  in

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Press Fabric Manufacturing
Blending
Warping
Carding
Weaving
Batt Formation
Picking Inspection
Needling
Heat Setting
Quality check packing
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From yarn...
Warp
Weft
...to base fabric
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Base Fabric
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MORPHOLOGY OF BATT FIBERS
44 dtex
30
22
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70 µm
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6.7
19 µm
3.1

• 11 dtex 10 000 meters of fibers have the weight
  of 11 grams

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Needling Machine
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Batts Laying
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Press Felt Design
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Press Fabrics General Design

• Fine top batt (Paper Side)
• Coarser top batt
• Woven base-structure
• Coarse bottom batt (Roll side)

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3
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Press Fabrics Base Fabric Types

• 1 Layer

11 Laminate
2 Layer
21 Laminate
Fabric volume, compaction resistance and water
capacity are specified by the structure of the
woven base.
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- Single layer Base
Press Felt Designs

• Single Layer base design
• Twisted monofilament in warp
• Monofilament in weft
• Stable, easy to clean base
• Twisted monofilament yarns are stronger and
  flexible in nature

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Single layer Felt design
Felt GSM 850 1200 Base GSM 315 -
400 MD Yarn Nylon monofilament / Twisted MD
Yarn /10cm 79 87 CMD Yarn Nylon
monofilament CMD Yarn/10cm 79 94
Application Slow speed machines
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- Double layer Base
Press Felt Designs

• Double Layer base design
• Twisted monofilament in warp
• Monofilament in weft
• Stable, easy to clean base
• Twisted monofilament yarns are stronger and
  flexible in nature

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Double layer Felt design
Felt GSM 1150 1400 Base GSM 475 590
MD Yarn Nylon monofilament / Twisted MD
Yarn/10 cm 134 174 CMD Yarn Nylon
monofilament CMD Yarn/10 cm 79
94 Application Moderate press load and
medium speed machine
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- Laminated Base
Press Felt Designs

• Two component base
• Either Single / double / combination layer
  bases
• Bases put over one another are needled
• Weft either Mono or Twisted Monofilament
• Uniform water flow due to high void volume
• Resistance to Base mark
• Resistance to high nip load

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Laminated Felt design
Felt GSM 1300 1750 Base GSM 630 800
MD Yarn Nylon monofilament / Twisted MD
Yarn/10 cm 158 174 CMD Yarn Nylon
monofilament CMD Yarn/10cm 158
188 Application High speed and high nip load

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Press Fabrics Advanced Felts

• Membrane or
• non-woven layers

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The Non-woven concept
The Planar Family
Base structures
Integrated components
O2 Planar
O3 Planar
Vector
Spectra
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The Planar Family
Why Non-woven felts?
Benefits with Non-woven felt structures

• Extremely fast start-up
• High dewatering
• Marking Free - No weave knuckles
• Excellent pressure uniformity
• Very good dimensional stability

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The Planar Family
Vector Planar designs
Additional benefits with Vector Technology

• Increased capacity
• Increased flexibility
• Increased compaction resistance
• Maintained permeability
• Increased felt life

V3 Planar
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Cross Direction View Vector Felt
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The Planar Family
Spectra Planar designs
Additional benefits with Spectra Technology

• Extremely fast start-up
• High dewatering
• Excellent compaction resistance
• Unique vibration reduction characteristics
• Well maintained felt properties over felt life

S3 Planar
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Seam fabrics Benefits

• Safer to install
• Easier to install
• Reduced fabric changing time
• Improved machine efficiency

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Seam Felts

• Demands for Seam felts
• Easy to install
• Easy to seam
• Strong seam area
• Non marking

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Seam
Magnification 20x
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Press Fabrics Influence on Paper
QualitySmoothness
Single FiberImprint50 µm
Coarse Fabric
Single FiberImprint20 µm
Smooth Fabric
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Press Fabrics Influence on Paper
QualitySmoothness
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The Future for Press Fabric Design
Market Requirement
Paper Makers Need

• - High nip load speed
• - Low grade Recycle fibre
• Mark free paper
• Low GSM paper

• - Easy installation
• - Longer felt life
• Dimensional stability
• Higher dryness

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