Fiber Web Cooling Before Calendering to Preserve Bulkiness
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Solution Overview
Problem
Calendering of fiber webs faces challenges in achieving required surface properties while maintaining high bulkiness, and the reeling process often results in reduced brightness due to warm web temperatures, necessitating cooling devices.
Innovation Solution
Cooling the fiber web to temperatures not higher than 40°C before calendering and reeling it after calendering to maintain temperatures below 50°C, with a short dwell time in the calendering nip and utilizing cooling means like fresh air flows or moisture vaporization for latent thermal cooling, to reduce raw material usage and prevent brightness loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fiber web is calendered at high temperature to improve surface smoothness, then surface properties are enhanced, but bulkiness is reduced and brightness is lost
Solution Approach 1:
The patent applies parameter changes by cooling the fiber web before calendering to temperatures of 0°C or below, then conducting calendering at controlled temperatures to achieve surface smoothness while preserving bulkiness. This temperature parameter modification allows the calendering process to occur under conditions that minimize bulk loss while still achieving the desired surface properties.
Solution Approach 2:
The patent employs preliminary action by cooling the fiber web before it enters the calendering process. The cooling means are positioned upstream of the calendering nips to pre-cool the web to 0°C or below before calendering occurs. This preliminary cooling prepares the material in a state that resists excessive compression and bulk loss during subsequent calendering.
2Manufacturing precision
If the fiber web is calendered to achieve required surface properties, then surface quality improves, but raw material consumption increases
Solution Approach 1:
By changing the temperature parameter to 0°C or below before and during calendering, the patent achieves effective surface smoothing with reduced material compression. This parameter modification allows for achieving surface quality targets while minimizing the need to add excess raw material to compensate for compression losses.
3Ease of operation
If the fiber web is reeled at warm temperature after drying, then handling is easier, but brightness is reduced
Solution Approach 1:
The patent applies preliminary action by implementing cooling means before the calendering section that cool the fiber web to 0°C or below. This preliminary cooling maintains lower temperatures through the calendering and drying processes, ensuring that when the web is reeled, the temperature is controlled to preserve brightness while still allowing for manageable handling characteristics.
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 method achieves higher bulkiness with reduced raw material consumption and minimizes brightness reduction during reeling, enhancing surface smoothness and reducing calendering bulk loss, thereby addressing environmental and cost-saving concerns.
Implementation Method 1
cooling the fiber web to temperatures not higher than 40°C before calendering and reeling it after calendering such that the temperature of the web is not higher than 50°C
Implementation Method 2
utilizing cooling means like fresh air flows or moisture vaporization for latent thermal cooling
Implementation Method 3
moisture vaporization for latent thermal cooling
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a method for producing a fiber web (W), in which method the fiber web (W) is calendered in at least one calendering nip (NA; NB) of at least one calender (20A; 20B) and reeled up in a reel-up (40). The fiber web (W) is cooled by cooling means (10A; 10B) before calendering to temperatures of not higher than 40 °C, preferably to temperature in the range of 10 - 30 °C. The invention also relates to a production line for producing fiber webs (W), which comprises at least one calender (20A; 20B) with at least one calendering nip (NA; NB) and a reel-up (40) after the calender (20A; 20B). The production line comprises at least one cooling means (10A; 10B) before the at least one calender (20A; 20B) for cooling the fiber web to temperatures of not higher than 40 °C, preferably to temperature in the range of 10-30 °C.