Stirrer Mill Agitator Disk Indentations for Plaited Flow
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Solution Overview
Problem
Existing agitator mills face challenges in achieving intensive grinding and dispersing processes while maintaining effective separation of grinding aids and coarse particles, leading to reduced active grinding chamber size and increased separation area.
Innovation Solution
The design incorporates indentations in the last agitator disk to maintain plaited flows, allowing for tangential acceleration and separation of auxiliary grinding bodies and coarse particles within the separating device, while finely ground material is deflected and discharged through the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between the last agitator disk and the adjacent agitator disk is significantly reduced to enable pre-classification, then the separation of auxiliary grinding bodies and coarse particles is improved, but the active grinding chamber size is reduced
Solution Approach 1:
The patent applies local quality by creating indentations only in the last agitator disk rather than modifying the entire agitator system. These localized indentations generate plaited flows specifically in the region between the last and adjacent agitator disks, enabling pre-classification functionality without affecting the overall grinding chamber volume or other agitator disks.
Solution Approach 2:
The patent segments the grinding chamber into distinct functional zones by using indentations to create plaited flows that separate the classification function from the main grinding volume. This segmentation allows the last agitator disk region to serve dual purposes: maintaining grinding function while enabling pre-separation, thus preserving active grinding chamber size.
2Productivity
If the distance between adjacent agitator disks is increased to allow plaited flows, then the grinding and dispersing process is improved, but the overall length of the mill increases
Solution Approach 1:
The patent solves the space constraint by introducing a radial dimension through indentations in the last agitator disk. These indentations create plaited flows that utilize the radial space within the existing mill length, rather than requiring additional axial length. This dimensional approach allows intensive grinding with plaited flows without increasing the overall mill length.
3Productivity
If indentations are added to the last agitator disk to maintain plaited flows, then the grinding and dispersing process is intensified, but the device complexity increases
Solution Approach 1:
The patent minimizes device complexity by applying the indentation feature only to the last agitator disk rather than modifying all agitator disks. This localized modification creates the necessary plaited flows for intensive grinding while keeping the rest of the agitator system simple and unchanged, thus limiting the increase in device complexity.
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 enables a more intensive grinding and dispersing process without increasing the overall length, ensuring effective separation of grinding aids and coarse particles, thereby optimizing the grinding chamber's efficiency.
Implementation Method 1
the distance between the agitator discs, with the exception of the last agitator disc, is so great that so-called plaited flows occur, i.e. the material to be ground with the auxiliary grinding bodies flows out adjacent to the agitator discs due to the tangential impulses applied by the agitator discs
Implementation Method 2
the auxiliary grinding bodies and coarse particles that have not yet been sufficiently ground being spun off essentially radially through the openings in the cage
Data Source
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AI summary
A stirrer mill comprises a milling vessel (2) and a stirring shaft (5) arranged such that it can be driven to rotate therein. Mounted at the end of the stirring shaft (2) is a last stirring disc (17) on which is mounted a substantially cylindrically shaped cage (19) having perforations (20). Inside the cage (19) is arranged a screening device (23). The distance between a second-last stirring disc (14) and the last stirring disc (17) is such as to form a braided flow (29) while avoiding a preclassification of grinding material on the one hand and grinding aids (28) and coarse grinding material particles on the other hand. In the last stirring disc (17) are formed openings (22) through which the grinding material together with the grinding aids (28) passes, whereupon the grinding aids (28) and the coarse grinding material particles are separated inside the separating chamber (21) formed by the last stirring disc (17) and the cage (19). In the last stirring disc (17) are formed depressions (27) which promote the formation of a braided flow (29) between the last stirring disc (17) and an adjacent stirring disc (14).