Defibrating Unit Moisture Control for Sheet Strength
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Solution Overview
Problem
Conventional dry-type sheet manufacturing apparatuses produce sheets with insufficient strength due to the inclusion of short fibers and fiber clumping, resulting in surface unevenness, which is exacerbated by varying moisture levels in the defibration object.
Innovation Solution
A sheet manufacturing apparatus equipped with a defibrating unit, a measuring unit to detect moisture levels, and a controller that adjusts the operating conditions of the defibrating unit based on moisture content, such as rotational speed and pressure, to optimize defibration and prevent fiber clumping and short fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If dry-type sheet manufacturing apparatus is used to reduce water consumption, then water usage is reduced, but sheet strength becomes insufficient due to fiber clumping and short fibers
Solution Approach 1:
The patent applies parameter changes by adjusting the rotational speed of the rotating blade in the defibrating unit based on moisture content measurements. When moisture content is high, the blade rotates at higher speed to increase defibration effectiveness. When moisture content is low, the blade rotates at lower speed to prevent excessive defibration and short fiber generation. This dynamic parameter adjustment resolves the contradiction by optimizing defibration for each condition.
Solution Approach 2:
The patent implements feedback control by using a moisture content measuring unit to continuously monitor the moisture level of the defibration object and feeding this information back to the controller. The controller then adjusts the rotating blade speed accordingly. This closed-loop feedback system ensures optimal defibration performance while preventing fiber clumping and short fiber formation, thereby maintaining sheet strength.
2Manufacturing precision
If rotating blade rotates at high speed to increase defibration effectiveness, then fiber clumping is reduced, but short fibers increase and sheet strength decreases
Solution Approach 1:
The patent dynamically changes the rotational speed parameter of the rotating blade based on real-time moisture content measurements. The controller adjusts the blade speed to match the actual conditions of the defibration object, using higher speeds only when necessary (high moisture conditions) and lower speeds when conditions permit (low moisture conditions). This prevents excessive defibration and short fiber generation while maintaining adequate defibration effectiveness.
Solution Approach 2:
The patent transitions from a fixed-speed rotating blade system to a dynamic, variable-speed system that adapts to changing moisture conditions. The controller continuously adjusts the blade rotation speed based on feedback from the moisture measuring unit, allowing the system to optimize defibration performance for each specific condition while avoiding the drawbacks of consistently high-speed operation.
3Manufacturing precision
If pressure applied to defibration object is increased to reduce fiber clumping, then defibration effectiveness improves, but short fibers increase and sheet strength becomes insufficient
Solution Approach 1:
The patent changes the pressure parameter by adjusting the rotating blade speed, which directly influences the pressure applied to the defibration object. Higher blade speeds generate higher pressure that reduces fiber clumping, while lower speeds generate lower pressure that prevents excessive defibration and short fiber formation. The dynamic adjustment based on moisture content ensures optimal pressure application for each condition.
Data Source
AI summary
A sheet manufacturing apparatus includes a defibrating unit configured to defibrate a defibration object, a measuring unit configured to acquire information relating to the moisture contained in the defibration object, and a controller configured to modify an operating condition of the defibrating unit based on the information.