Non-contact Gas Cooler for Fiber Web Bulk Preservation
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Solution Overview
Problem
Existing fiber web production lines face challenges in achieving the required surface properties and bulkiness while minimizing raw material usage, as high bulkiness can lead to reduced basis weight and increased material costs.
Innovation Solution
A production line design that includes a head box, press section, drying section, gas cooler, moisturizing device, calender, and coating section, with a non-contact cooling system between the calender and last drying cylinder, using dry, cool gas with a partial steam pressure lower than the fiber web, and impingement drying modules to control moisture evaporation and maintain high production capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the fiber web is cooled before calendering to save bulkiness, then bulk loss is reduced, but the production process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces the conventional mechanical contact cooling system with a non-contact infrared heating/cooling system. The infrared heater (22) can be positioned close to the fiber web without physical contact, allowing rapid temperature adjustment before calendering. This substitution reduces mechanical complexity while achieving the same bulk preservation effect through radiant energy transfer rather than conductive cooling.
Solution Approach 2:
The patent dynamically adjusts the temperature parameter of the fiber web using infrared radiation. By controlling the infrared heater's power and positioning, the system can rapidly heat or cool the fiber web to the optimal temperature range for calendering, preserving bulkiness without requiring complex mechanical cooling infrastructure.
2Loss of substance
If the fiber web is cooled before calendering to reduce bulk loss, then material usage is optimized, but production time increases
Solution Approach 1:
The infrared heating/cooling system enables rapid temperature adjustment without the time delays associated with mechanical contact cooling. The radiant energy transfers heat directly to the fiber web molecules, achieving temperature changes in seconds rather than minutes, thus preserving bulkiness while maintaining high production speeds.
Solution Approach 2:
The system performs preliminary temperature adjustment of the fiber web immediately before calendering using infrared radiation. This pre-conditioning of the fiber web to the optimal temperature range ensures bulk preservation during calendering while minimizing the time required for temperature adjustment, thereby reducing overall production time.
3Stability of the object's composition
If non-contact cooling is used between calender and drying section, then bulkiness is maintained, but energy consumption increases
Solution Approach 1:
The infrared system uses radiant energy which can be precisely controlled and targeted only at the fiber web surface requiring temperature adjustment. This is more energy-efficient than mechanical contact cooling systems that require continuous operation of large cooling mechanisms throughout the production line. The infrared heater (22) can be activated only when and where needed, reducing overall energy consumption.
Solution Approach 2:
The infrared heating/cooling system applies energy locally to specific zones of the fiber web that require temperature adjustment. The infrared heater (22) can be positioned to target only the area between the calender and drying section, avoiding unnecessary energy consumption in other parts of the production line. This localized energy application maintains bulkiness while minimizing total energy usage.
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 solution enables the production of fiber webs with high bulkiness and reduced raw material usage, achieving efficient surface properties and cost-effectiveness while maintaining high production speeds and quality, suitable for producing board and paper webs with varying basis weights and coating layers.
Implementation Method 1
at least one cooler providing gas, for example air or air-mixture or gas-mixture, blows after the press section
Implementation Method 2
at least one moisturizing device located before at least one cooler providing gas blows
Data Source
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Figure 5
AI summary
The invention relates to a production line for producing fiber webs comprising at least one head box, which can be a two or three layer head box, forming section comprising forming means for each layer or layer combination of the fiber web (W), a press section with at least one press nip, at least one drying section (142, 143; 152;), at least one cooler (144) providing gas blows towards the fiber web (W) at a location at least after the press section, at least one calender (15), a reel-up. The production line comprises between at least one calender (15) and the last drying cylinder of the drying section (143) located before the calender (15) next to it at least one cooler (144) for cooling the fiber web (W) and that length of the fiber web run between the calender (15) and the last drying cylinder before it is 7 - 20 m, advantageously 10 - 15 m measured from last contact point of the fiber web (W) on the last drying cylinder to first contact point of the fiber web (W) on first calender roll forming a calendering nip of the calender (15). The invention also relates to a cooler (144) providing gas blows and comprising at least one cooler module and at least one cooler module of the cooler (144) is curved and at least one module (43) is provided as an gas turn module for turning run of the fiber web (W) from its main running direction 80 - 190 °.