Offset-Inlet Fiberising Grinder for High-Throughput Web Shredding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fiberising processes for cellulose-based materials, such as paper and cardboard, face challenges in improving material throughput and reducing costs.
Innovation Solution
A grinder design featuring a rotor with a blade edge and a processing edge that cross each other during rotation, allowing for shredding of elongate webs or stacks of webs without prior size reduction, combined with an inlet that controls orientation and position, and an airflow mechanism to distribute shredded material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional cutting methods are used to reduce material size before grinding, then material can be processed, but preliminary size reduction increases device complexity and processing time
Solution Approach 1:
The inlet is configured to control the orientation of the web at least partly between the first and second radius before the material reaches the blade, performing preliminary positioning action that eliminates the need for separate size reduction steps
Solution Approach 2:
The blade serves multiple functions: it acts as both a cutting tool and a distributing element for particulate material towards the circumferential grinding track, while the inlet simultaneously controls both material feed and orientation
2Productivity
If the rotor processes material at high speed, then fiberisation efficiency improves, but load variations on the rotor edges increase causing instability
Solution Approach 1:
The blade is positioned to extend from a first radius to a second, larger radius, creating different functional zones along its length that distribute loading more evenly on the rotor edge during high-speed operation
Solution Approach 2:
The blade acts as an intermediary element that gradually introduces material into the grinding track, mediating between the high-speed rotor and the material to be processed, thereby reducing shock loads and stabilizing rotor operation
3Manufacturing precision
If the blade is positioned to shred material effectively, then fiberisation quality improves, but power requirements increase
Solution Approach 1:
The blade is divided into different radial sections (first radius to second radius) that perform different functions: the inner section performs initial shredding while the outer section distributes material, segmenting the energy requirement across different zones
Solution Approach 2:
The configuration replaces high-power direct impact shredding with a more efficient mechanical system where the blade geometry and rotation create optimized cutting and distributing actions that achieve the same fiberisation quality with lower power input
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
Enhances material throughput and reduces power requirements by minimizing load variations on the rotor edges, facilitating continuous operation and efficient fiberisation of cellulose-based materials.
Implementation Method 1
the blade edge and processing edge cooperate and cross each other providing a crossing point moving radially outward along the processing edge for shredding the web or webs
Implementation Method 2
An airflow in the grinder may entrain shredded and/or fiberized material through the grinder, e.g. into and/or along a grinding track
Implementation Method 3
the rotor and/or housing comprising along at least part of its (their) circumference and axial length, a plurality of grinding members for impacting and agitating the material in the grinding track
Data Source
Figure 1
Figure 2
AI summary
A grinder for fiberising cellulose-based material, in particular a whirl mill, comprises a rotor being rotary in a housing about an axis of rotation and having an axial end face provided with a blade extending in axial direction from the face from a first radius to a second, larger, radius and providing a blade edge, and an inlet being configured to direct an elongate web or stack of webs of the material longitudinally to the end face and to control orientation of the web or stack of webs at least partly between the first and second radius, wherein the inlet is offset from the axis of rotation of the rotor.