Extended Press Nip Profile for Fibrous Web Dewatering

Solution Overview

Problem

Existing press arrangements for fibrous webs face challenges in reducing energy costs and CO2 footprint while avoiding web crushing, particularly in the production of packaging paper webs, due to limitations in line load and geometric configuration of press elements.

Innovation Solution

A press arrangement with a main press configured to achieve a line-load ratio (LLR) between 0.69 and 1.52, utilizing a weighted line load (WLL) integrated with a weighting factor, and optionally incorporating a pre-press, to optimize dewatering efficiency and reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the line load is increased to achieve higher dry content, then dewatering efficiency is improved, but the risk of crushing the fibrous web increases

Engineering Contradiction:

Improvedry contentVSAvoidweb integrity

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The press arrangement applies different line loads at different locations along the press nip. The geometric configuration of the press elements creates a non-uniform pressure distribution, with higher pressures in specific regions and lower pressures in others, allowing efficient dewatering without crushing the web uniformly across the entire nip.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The press arrangement dynamically adjusts the line load through its geometric configuration, creating a variable pressure profile along the press nip. This dynamic pressure distribution allows the system to adapt the pressing force to local requirements, maximizing dewatering efficiency while protecting web integrity.

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If the line load is increased to achieve higher dry content, then dewatering efficiency is improved, but energy consumption increases

Engineering Contradiction:

Improvedry contentVSAvoidenergy consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The press arrangement applies different line loads at different locations along the press nip. The geometric configuration of the press elements creates a non-uniform pressure distribution, with higher pressures in specific regions and lower pressures in others, allowing efficient dewatering without crushing the web uniformly across the entire nip.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The press arrangement dynamically adjusts the line load through its geometric configuration, creating a variable pressure profile along the press nip. This dynamic pressure distribution allows the system to adapt the pressing force to local requirements, maximizing dewatering efficiency while protecting web integrity.

Inventive Principle:

Principle #15Dynamics

3Quantity of substance

If the line load is increased to achieve higher dry content, then dewatering efficiency is improved, but investment costs increase due to more massive framing structure

Engineering Contradiction:

Improvedry contentVSAvoidinvestment costs

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The press arrangement applies different line loads at different locations along the press nip. The geometric configuration of the press elements creates a non-uniform pressure distribution, with higher pressures in specific regions and lower pressures in others, allowing efficient dewatering without crushing the web uniformly across the entire nip.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The press arrangement dynamically adjusts the line load through its geometric configuration, creating a variable pressure profile along the press nip. This dynamic pressure distribution allows the system to adapt the pressing force to local requirements, maximizing dewatering efficiency while protecting web integrity.

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The press arrangement achieves more efficient dewatering of fibrous webs, particularly packaging paper webs, with reduced energy costs and CO2 footprint, while maintaining web integrity at high production speeds and using recycled fibers.

Implementation Method 1

the fibrous web is dewatered by mechanical pressure

Methodology Applied

Scientific EffectMechanical pressure: Mechanical Force

Data Source

PatentUS20260022518A1Press arrangement and method for pressing a fibrous web

Publication Date: 2026.01.22 VOITH PATENT GMBH

AI summary

A press arrangement and method for pressing a fibrous web include a main press with extended press nip having a length of at least 150 mm. The main press is configured such that, when operated with a line load LL of at least 1,200 kN/m, a line-load ratio LLR of at least 0.69 and at most 1.52 is obtained. The line-load ratio LLR is defined as the quotient of a weighted line load WLL to the line load LL, the weighted line load WLL being the result of integration of the squared local pressure p(x)2, weighted with a weighting factor A, over the nip length x, the weighting factor A being one divided by ten megapascal. The line load LL is the result of integration of the local pressure p(x) over the nip length x, such that the following formula for the line-load ratio LLR applies:LLR=WLLLL=∫A*p⁡(x)2⁢dx∫p⁡(x)⁢dx=∫110⁢ MPa*p⁡(x)2⁢d⁢x∫p⁡(x)⁢d⁢x