Pressing Part of the Paper Machine (PM)

The paper pressing stage is the final process for mechanically extracting water from the paper web in the PM line. There is a wide variety of presses, each with one or more pressing zones, that can be optimally combined to form an adequate press part. The press part must be designed to align with the machine’s performance, speed, product requirements, and the methods for felt and roll removal.

Standard Technical Parameters of the Press Part

• Operational Speed:
  • Up to 1,200 m/min for standard presses
  • Up to 2,200 m/min for tissue presses
• Operational Width:
  • Up to 7,500 mm
• Felt Tension:
  • Up to 5 kN/m
• Material Design:
  • Common steel
  • Common steel wrapped by an anti-corrosive metal plate
  • Stainless steel

Types of Presses and Their Configurations

1. Continuous Standard Presses:

• NIP Width: 20 – 30 mm
• Pressure: Up to 150 kN/m
• Configurations:
  • Single-felt
  • Double-felt
  • Double-felt with a suction roll

2. Combi Press:

• NIP Width: 20 – 30 mm
• Pressure: Up to 110 kN/m
• Configurations:
  • With a smooth central roll
  • With a suction central roll

3. Extended Pressing Zone Presses (JUMBO):

• NIP Width: 60 – 75 mm
• Pressure: Up to 350 kN/m
• Configurations:
  • Single-felt
  • Double-felt

4. Shoe Press:

• NIP Width: 200 – 250 mm
• Pressure: Up to 1,000 kN/m
• Configurations:
  • Single shoe press
  • Double shoe press
  • Triple-NIP

Press Part Components

• Vacuum Water Boxes and Suction Boxes:
  • Essential for water removal from the paper web during pressing.

Press Configurations and Their Benefits

Continuous Standard Presses:

• Efficient for high-speed operations.
• Suitable for a range of paper types and production speeds.
• Options for single or double felt arrangements enhance versatility.

Combi Presses:

• Combine different pressing elements for optimal dewatering.
• Central rolls, either smooth or suction, provide flexibility in press design.

Extended Pressing Zone Presses (JUMBO):

• Larger NIP width and higher pressure capabilities.
• Enhanced dewatering due to extended contact time.
• Suitable for producing thicker paper grades.

Shoe Presses:

• Provides the highest NIP width and pressure.
• Ideal for maximum dewatering and high bulk paper production.
• Multiple configurations for varying operational needs and paper types.

Conclusion

The pressing part of the paper machine is crucial for efficiently removing water from the paper web. With a range of press types and configurations, the press part can be tailored to meet specific operational speeds, widths, and product requirements. The correct combination of presses ensures optimal performance, higher productivity, and better-quality paper production.