Defibration Surface with Segmented Wave Form and Grits
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Solution Overview
Problem
The existing mechanical pulping processes are inefficient due to high energy consumption and the inability to effectively separate fiber loosening and peeling phases, leading to compromised fiber fatigue and peeling quality.
Innovation Solution
A grinding surface with a base wave form for fiber loosening and synthetic or semisynthetic grits for peeling, where at least 90% of grit protrusions have a variation within the average grit diameter, allowing for a distinct separation of fatigue and peeling phases, reducing energy consumption by optimizing strain pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional grinding with uniform grit structure is used for both fiber loosening and peeling, then the process is simple to operate, but energy consumption is high and fiber quality is compromised
Solution Approach 1:
The grinding surface is segmented into two distinct functional zones: a base wave form structure for fiber loosening and a grit layer for fiber peeling. This segmentation allows each zone to be optimized for its specific function, reducing overall energy consumption while improving fiber quality
Solution Approach 2:
Different regions of the grinding surface are given different properties: the base wave form provides a specific amplitude and wavelength for effective loosening, while the grit layer provides controlled protrusions for peeling. This local differentiation enables efficient energy use and high-quality fiber separation
2Productivity
If high peripheral speeds are used in grinding, then production level increases, but energy consumption increases and fiber quality decreases
Solution Approach 1:
The base wave form creates periodic compression and relaxation cycles during the grinding process. This periodic action enhances fiber loosening efficiency, allowing effective defibration at lower peripheral speeds and thus reducing energy consumption while maintaining high production levels
3Manufacturing precision
If grit protrusions have large variation in height, then fiber peeling is more effective, but fiber cutting increases and energy consumption rises
Solution Approach 1:
The grit protrusions are controlled to have specific dimensional parameters with limited variation (standard deviation less than 30% of mean protrusion height). This parameter control ensures effective fiber peeling while minimizing fiber cutting and reducing energy consumption
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 specific energy consumption by up to 50% while maintaining pulp quality, enabling higher production levels with improved fiber properties and reduced fiber cutting, thus enhancing the mechanical defibration process.
Implementation Method 1
a more efficient loosening (i.e. fatigue) process could be achieved with a surface wave form
Implementation Method 2
A defibration surface (grinding surface) with a base wave pattern having a specific amplitude and specific wave length can be used for mainly performing the fatigue phase
Implementation Method 3
the fiber separation phase is carried out with synthetic or semisynthetic grits of a preselected dimension and form
Data Source
AI summary
The present invention provides a novel method and apparatus for producing pulp from lignocellulosic raw material, such as wood or annual or perennial plants, by mechanical defibration. According to the invention, fibers are peeled from the wood by means of grinding grits arranged on a defibration surface, wherein at least 90% of the protrusion difference distribution between adjacent or neighboring grits on the surface belongs to a value region maximally as wide as the average grit diameter. By means of the invention, a reduction in specific energy consumption of up to 50% or even more can be obtained.