Stirred Mill Separation Geometry to Prevent Media Clogging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stirred mills face issues with grinding media accumulation on the separation device due to drag forces, leading to clogging and potential shutdowns, especially when handling thermally sensitive or hazardous materials.
Innovation Solution
The solution involves optimizing the distance between the rotor and the separation device based on grinding media diameter, setting a maximum value for this distance, and incorporating scraping tools to prevent media accumulation, ensuring a continuous product flow and rapid particle size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the distance between the rotor and the separation device is increased, then the separation device diameter can be larger, but grinding media accumulation on the separation device increases due to drag forces
Solution Approach 1:
The patent applies parameter changes by establishing a specific mathematical relationship between the distance s, rotor inner diameter d351, separation device diameter d30, and grinding media diameter c. The formula s = 0.5 · (d351 - d30) ≤ 5 · c defines precise parameter ranges that optimize both separation device size and prevent media accumulation, resolving the contradiction between larger separation area and reduced accumulation.
2Reliability
If scrapers are added to the separating device to prevent grinding media accumulation, then media accumulation is reduced, but heat is generated within thermally sensitive materials
Solution Approach 1:
The patent extracts the scraping function from the separation device by implementing the distance optimization formula that prevents media accumulation passively through geometric configuration rather than active mechanical scraping. This removes the heat-generating scraper component while maintaining the benefit of accumulation prevention, resolving the contradiction between reliability and temperature control.
3Reliability
If the distance between rotor and separation device is reduced, then grinding media accumulation is prevented, but the separation device diameter must be smaller
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by defining the distance s as a function of both rotor dimensions and grinding media size. The formula allows the separation device to achieve adequate diameter for separation functionality while maintaining sufficiently small distance to prevent media accumulation, balancing both requirements through mathematical parameter relationships.
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 effectively prevents grinding media accumulation, maintaining a continuous product flow and enhancing particle size reduction efficiency, particularly suitable for thermally sensitive substances.
Implementation Method 1
The grinding media are accelerated and concentrated outwards by the tools attached to the rotor, which extend close to the container wall, and by the resulting centrifugal forces.
Implementation Method 2
The accumulation of grinding media on the separating device can repeatedly lead to increased pressure in the agitator mill... the core of the invention consists in effectively preventing the accumulation of grinding media on the separation device by reducing the distance between the rotor and the separation device
Data Source
Figure 1
AI summary
The invention provides a stirred mill for processing free-flowing materials. The stirred mill comprises a grinding container (2), a grinding chamber (8) bounded by a container wall (9), and an agitator rotatable about the central longitudinal axis (19) with a rotor (35) having an inner diameter d351. Tools (38) are attached to the rotor and extend towards the container wall (9). The stirred mill also has an inner stator (22) arranged inside the rotor (35). A material discharge channel (47) is formed between the rotor (35) and an outer wall (23) of the inner stator (22), through which the material is conveyed to the separating device (30) and then to a discharge line (31). The grinding chamber (8) is at least partially filled with grinding media having a diameter c. Above the inner stator (22) a separating device (30) with a diameter d30 is arranged.For the distance s between rotor (35) and grinding media separation device (30) s = 0.5*(d351 - d30) ≤ 5 *c.