Sheet Manufacturing Apparatus with Asymmetric Heating
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Solution Overview
Problem
Existing dry sheet manufacturing methods generate excessive paper dust due to uneven heating of defibrated products, which affects the quality and efficiency of the sheet manufacturing process.
Innovation Solution
A sheet manufacturing apparatus and method that includes an accumulating unit for forming a web, a moisture adding unit to set the moisture content between 12% and 40% mass, and a heating unit with a temperature gradient across its surfaces to control heating, ensuring the surface in contact with higher moisture is heated more than the other surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If moisture is sprayed from one surface side and the paper is heated, then the sheet can be manufactured with reduced water usage, but a large amount of paper dust is generated
Solution Approach 1:
The heating unit applies different temperatures to different surfaces of the web. The first surface (where moisture was sprayed) is heated at a higher temperature than the second surface, creating localized quality differences in the heating process that prevent paper dust generation while maintaining water efficiency
Solution Approach 2:
The patent changes the temperature parameter across different surfaces of the heating unit. By making the surface temperature of the first portion higher than the second portion, the heating parameters are optimized to reduce paper dust while maintaining effective sheet formation
2Productivity
If the temperature of the heater roller is increased to improve heating efficiency, then the sheet can be formed faster, but paper dust generation increases
Solution Approach 1:
Different surfaces of the heating unit are assigned different temperature levels. The first surface contacts the web at a higher temperature for efficient heating, while the second surface operates at a lower temperature to prevent paper dust generation, thus achieving both productivity and quality control
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 paper dust generation, enhances production efficiency, and improves the mechanical strength of the sheets by effectively bonding fibers through controlled moisture and heat application.
Implementation Method 1
The heating unit heats the web in a state of a surface temperature of the first portion being higher than a surface temperature of the second portion
Implementation Method 2
a moisture adding unit that adds moisture from a side of one surface of the formed web
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A sheet manufacturing apparatus including an accumulating unit that causes a defibrated product to accumulate in a dry manner and forms a web, a moisture adding unit that adds moisture from a side of one surface of the formed web such that a moisture content of the web is equal to or more than 12 mass% and equal to or less than 40 mass%, and a heating unit that heats the web to which moisture is added. The heating unit has a first portion that comes in contact with the one surface of the web and a second portion that comes in contact with another surface of the web, and the heating unit heats the web in a state of a surface temperature of the first portion being higher than a surface temperature of the second portion.