Horizontal Dry Mill Screw Gap Design
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Solution Overview
Problem
Existing horizontal dry mills face issues with raw material blow-up and adhesion to the input section due to centrifugal forces, leading to clogging and reduced grinding efficiency, especially when processing materials with low specific gravity or high cohesion.
Innovation Solution
The horizontal dry mill design incorporates a raw material supply section with a diameter smaller than the grinding chamber, and a mechanical thrust generating device with a reduced diameter, along with a gap between the screw and the grinding tank to minimize centrifugal forces, and uses a plate-like agitation member with specific gaps to prevent adhesion and buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional horizontal dry mill with simple arm agitation elements is used, then the structure is simple, but raw material with high flowability passes through the grinding chamber without filling the upper region, resulting in short retention time and poor grinding efficiency
Solution Approach 1:
The agitation member is segmented into multiple functional components: a rotary shaft, multiple arms extending radially, and lifting elements (such as blades or protrusions) attached to the arms. This segmentation allows each component to perform a specific function - the arms provide structural support while the lifting elements actively engage the raw material to prevent it from passing through unchanged, thereby improving grinding efficiency without excessive complexity.
2Duration of action of moving object
If a mechanical thrust generating device with large diameter is used to increase retention time, then centrifugal force increases and material blows up and adheres to the input section, causing clogging
Solution Approach 1:
The patent optimizes the diameter parameter of the mechanical thrust generating device to a specific range that balances two opposing requirements: it is large enough to generate sufficient centrifugal force for adequate retention time, but small enough to avoid excessive blow-up and adhesion of material to the input section. This parameter optimization resolves the contradiction between retention time and clogging prevention.
3Reliability
If the gap between the screw and grinding tank is reduced to prevent material buildup, then material is effectively contained, but the device complexity increases and maintenance becomes difficult
Solution Approach 1:
The patent specifies an optimal gap range between the screw (mechanical thrust generating device) and the grinding tank wall. This gap is small enough to effectively contain material and prevent buildup that would reduce grinding efficiency, but large enough to allow for practical manufacturing tolerances and ease of maintenance. The parameter optimization balances reliability with manufacturability.
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 configuration effectively suppresses clogging and adhesion, allowing for improved retention time and grinding efficiency by reducing centrifugal forces and preventing material buildup on the inner walls and separation members.
Implementation Method 1
a screw serving as a mechanical thrust generating device disposed on the side of the one end of the grinding chamber... a raw material input into the grinding chamber through the material input nozzle is thrust toward the discharge section by the screw
Implementation Method 2
it is agitated together with the grinding media and pulverized by means of mutual friction, shear, etc.
Implementation Method 3
it is agitated together with the grinding media and pulverized by means of mutual friction, shear, etc.
Implementation Method 4
whereafter a resulting pulverized product is separated from the grinding media by the separator and discharged from the discharge section
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
It is intended to, in a horizontal dry mill, prevent blow-up and adhesion of a raw material, etc., to a raw material input section. In a horizontal dry mill (10) of the present invention, a diameter of a raw material supply section (13) provided in a grinding tank (14) is set to be less than a diameter of a grinding chamber (12). Further, a diameter of a mechanical thrust generating device of the raw material supply section (13) is set to a small value according to the diameter of the raw material supply section. Furthermore, a gap (e1) between an outside dimension of a screw (26) as the mechanical thrust generating device and an inner diameter of the grinding tank (14) in the raw material supply section (13) is set between 0.5 mm and 1/3 of a diameter of each grinding medium M.