Counter-Rotating Grinding System for Powder Micronization
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Solution Overview
Problem
Existing grinding and mixing technologies face limitations in energy efficiency, scalability, and contamination issues, particularly when processing difficult-to-grind materials in a liquid phase, due to critical speed constraints and mechanical wear, leading to suboptimal processing times and volumes.
Innovation Solution
A counter-rotating grinding and mixing system with coaxial grinding and mixing mobiles driven by a power transmission system, such as bevel or epicyclic gear trains, operates at speeds exceeding conventional limits to enhance energy application and reduce mechanical stress, while maintaining thermal insulation and minimizing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional single rotor grinding systems are used, then the structure is simple, but the energy application per unit volume is limited and processing time is excessive
Solution Approach 1:
The single rotor is divided into two counter-rotating rotors. Each rotor contributes to the grinding action, effectively doubling the energy application capacity within the same volume. The counter-rotating configuration creates complementary flow patterns that enhance particle fragmentation and mixing efficiency.
Solution Approach 2:
Two rotors are combined in a counter-rotating configuration within the same grinding volume. The merging of two grinding actions into one system allows for increased power application without proportionally increasing the tank volume, thereby reducing processing time while maintaining compact size.
2Productivity
If higher rotation speeds are used to increase energy application, then processing efficiency improves, but mechanical wear and contamination increase
Solution Approach 1:
The two rotors are configured to rotate in opposite directions with equal speed. This counter-rotating arrangement creates balancing effects that reduce mechanical stress on the system components and minimize wear. The opposite rotation directions compensate for each other's centrifugal forces, reducing contamination risks.
3Stability of the object's composition
If the entire tank mass is set in motion for grinding, then mixing is achieved, but energy consumption per unit mass increases significantly
Solution Approach 1:
The grinding action is extracted from the tank wall movement and concentrated into two internal counter-rotating rotors. This allows the tank to remain stationary while the rotors perform the grinding and mixing functions, dramatically reducing the energy required to move the entire tank mass while maintaining effective mixing quality.
4Ease of manufacture
If conventional rotors are used, then the device is simple to operate, but the grinding capacity for difficult materials is insufficient
Solution Approach 1:
The system uses two rotors with adjustable counter-rotating speeds rather than a single fixed-speed rotor. This dynamic configuration allows optimization of the grinding action for difficult materials by adjusting the relative speeds and power distribution between the two rotors, while maintaining operational simplicity through automated 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
The system significantly increases energy application per unit volume and time, enhances processing efficiency, and reduces mechanical wear, enabling efficient micronization of difficult-to-grind materials without compromising integrity, thus optimizing particle size and processing capacity.
Implementation Method 1
These different devices exploit four main mechanisms inducing the fragmentation of the charge at the origin of the reduction in size of the particles constituting the charge to be ground, namely: impaction; shearing; compression; and attrition.
Implementation Method 2
These different devices exploit four main mechanisms inducing the fragmentation of the charge at the origin of the reduction in size of the particles constituting the charge to be ground, namely: impaction; shearing; compression; and attrition.
Implementation Method 3
These different devices exploit four main mechanisms inducing the fragmentation of the charge at the origin of the reduction in size of the particles constituting the charge to be ground, namely: impaction; shearing; compression; and attrition.
Implementation Method 4
These different devices exploit four main mechanisms inducing the fragmentation of the charge at the origin of the reduction in size of the particles constituting the charge to be ground, namely: impaction; shearing; compression; and attrition.
Implementation Method 5
the use of liquefied gas, due to its very low induced temperature (of the order of - 200°C for liquid nitrogen at atmospheric pressure), also makes it possible to weaken the materials to be ground and therefore limits the energy used to grind a given mass of material.
Implementation Method 6
they suffer from a limit on the energy level applicable to the material to be ground, in particular due to the centrifugal forces induced when the mobiles (attrition blades, rotors/turbines, propellers) are set into rotation.
Data Source
Figure 1~2
Figure 3A~5B
Figure 6A~6B
AI summary
The invention primarily relates to a device (1) for grinding and mixing powders (P), characterized in that it comprises: a grinding tank (2) containing the load of powders (P) to be ground in liquid phase; at least a first grinding and mixing moving member (4a) and a second grinding and mixing moving member (4b) disposed inside the grinding tank (2); a motorization system (M) for rotating said at least a first grinding and mixing moving member (4a) and a second grinding and mixing moving member (4b); a power transmission system (3) connecting the motorization system (M) to said at least a first grinding and mixing moving member (4a) and a second grinding and mixing moving member (4b), said at least a first grinding and mixing moving member (4a) and a second grinding and mixing moving member (4b) being driven in a counter-rotating manner.