Pulp Web Dewatering via Separated Clothing Zones
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Solution Overview
Problem
Existing methods for producing pulp webs, such as tissue or sanitary paper, face challenges in achieving low energy consumption and investment costs while maintaining high quality properties, particularly in effectively dewatering the pulp suspension without damaging the web.
Innovation Solution
The pulp web is guided on the first clothing between the forming roll and another roll, with the second clothing being lifted off and separately conditioned using high-pressure showers, fluid dispersal, and suction to reduce water load, allowing for improved dewatering when reattached, and the use of a suction roll with hot air or steam application to enhance dewatering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the second clothing is kept in contact with the first clothing during dewatering, then the pulp web can be formed continuously, but the second clothing becomes saturated with water and requires additional energy for drying
Solution Approach 1:
The patent extracts the second clothing from the contact with the first clothing in a specific section between the forming roll and the other roll. This allows the second clothing to be separately conditioned and dried using suction devices and fluid dispersal, removing the water saturation problem while maintaining continuous operation capability.
Solution Approach 2:
The patent segments the clothing interaction into distinct zones: contact zone for web formation, separation zone for independent conditioning, and re-contact zone for further processing. This segmentation allows targeted water removal from the second clothing without disrupting the continuous pulp web formation process.
2Quantity of substance
If the second clothing is lifted off and separately conditioned, then water load is reduced effectively, but the device complexity increases
Solution Approach 1:
The patent introduces intermediary devices (suction devices and fluid dispersal means) that act between the two clothings to remove water from the second clothing. These intermediaries enable effective water load reduction through controlled separation and targeted drying actions.
Solution Approach 2:
The patent changes the operational parameters of the second clothing by separating it from the first clothing, allowing independent control of water removal processes. This enables adjustment of drying intensity and timing to optimize water load reduction while managing system complexity.
3Productivity
If hot air or steam is applied to enhance dewatering, then dewatering efficiency improves, but energy consumption increases
Solution Approach 1:
The patent replaces purely mechanical dewatering with a hybrid system that incorporates thermal energy (hot air or steam) to enhance the dewatering process. This substitution increases dewatering efficiency by reducing water viscosity and enhancing evaporation, though it requires careful energy management.
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
This approach reduces energy consumption and investment costs while improving dewatering efficiency and quality characteristics of the pulp web, such as bulk and caliper, by effectively managing water load and applying thermal energy for viscosity reduction.
Implementation Method 1
the pulp suspension being dewatered by centrifugal force in the area of the forming roll
Implementation Method 2
reduction of the water load in the separately guided second clothing by means of a suction box
Implementation Method 3
applying thermal energy for viscosity reduction
Data Source
AI summary
A device and a method for producing a pulp web in which the first clothing and the second clothing are wrapped partly round the forming roll and another roll. The pulp web formed is guided between the forming roll and the other roll on the first clothing and the second clothing is guided separately from the first clothing, at least in one section. This enables the pulp web to be produced with low energy consumption and operating costs.