Jet Mill Classifier Gap Flushing for Fine Dry Particle Milling
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Solution Overview
Problem
Existing jet milling methods struggle to produce finest particles with narrow particle size distribution and prevent condensation issues during the grinding process, particularly when using superheated steam, leading to agglomeration and crust formation.
Innovation Solution
Implement a jet mill with an integrated dynamic air classifier and utilize gap flushing with low-energy compressed gases, combined with energy-rich superheated steam at controlled pressures and temperatures, to optimize the grinding process and prevent condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If superheated steam is used as grinding medium, then grinding efficiency and particle size reduction are improved, but condensation and agglomeration occur leading to crust formation
Solution Approach 1:
The system divides the steam flow into two separate paths: a main flow of superheated steam for grinding and a secondary flow of saturated steam for gap flushing. This segmentation allows each steam type to perform its specific function without interfering with the other, preventing condensation in the grinding zone while maintaining grinding efficiency.
Solution Approach 2:
Saturated steam acts as an intermediary substance that condenses in the classifier gap and shaft passage, creating a protective barrier that prevents water condensation and agglomeration in the grinding zone. This intermediary mechanism resolves the contradiction by allowing superheated steam to maintain high grinding efficiency while the saturated steam prevents harmful condensation effects.
2Object-generated harmful factors
If gap flushing with compressed gas is implemented, then condensation is prevented, but additional energy consumption occurs
Solution Approach 1:
The system changes the parameters of the flushing medium from high-energy superheated steam to low-energy saturated steam. This parameter change reduces the energy input required for gap flushing while still achieving effective condensation prevention. The saturated steam condenses at lower temperatures and pressures, creating an energy-efficient protective barrier in the classifier gap and shaft passage.
3Manufacturing precision
If superheated steam at high pressure is used, then particle size reduction is enhanced, but energy loss increases
Solution Approach 1:
The system uses partial action by applying high-pressure superheated steam only where needed for grinding, while using low-pressure saturated steam for gap flushing. This partial application of high-energy steam minimizes overall energy loss while still achieving the required particle size reduction in the grinding zone.
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
Achieves finer particle sizes with a narrow distribution and reduces agglomeration, allowing for efficient dry milling without additional drying steps and minimizing energy loss.
Implementation Method 1
at least one high-energy grinding jet of superheated steam with high flow energy is introduced
Implementation Method 2
the material to be ground and the material to be ground have at least approximately the same temperature
Implementation Method 3
In the classifier wheel, the coarser particles are separated from the airflow
Implementation Method 4
a gap flushing of the classifier gap and/or shaft passage with compressed gases of low energy content is carried out
Implementation Method 5
preventing condensation issues during the grinding process, particularly when using superheated steam, leading to agglomeration and crust formation
Data Source
Figure 1~3
Figure 2
AI summary
The invention relates to a method for producing very fine particles by means of a jet mill (1) comprising an integrated dynamic air separator (7) equipped with a separator wheel (8), a separator wheel shaft (35) and a separator housing (21). A separator gap (8a) is formed between the separator wheel (8) and the separator housing (21) and a shaft passage (35b) is formed between the separator wheel shaft (35) and the separator housing (21). The separator gap and/or shaft passage (35b) is rinsed with compressed gases having a low energy content and milling jet inlets (5) that are coated with energy-rich hot steam are provided. The invention further relates to a jet mill (1) comprising an integrated dynamic air separator (7) for producing very fine particles, equipped with a separator wheel (8), a separator wheel shaft (35) and a separator housing (21). A separator gap (8a) is formed between the separator wheel (8) and the separator housing (21) and a shaft passage (35b) is formed between the separator wheel shaft (35) and the separator housing (21). Rinsing devices are provided. Said rinsing devices rinse a separator gap and/or a shaft passage (35a) with compressed gases having a low energy content. Milling jet inlets (5) that are coated with energy-rich hot steam are provided. Due to said invention, the above-mentioned dynamic air separator (7) and a corresponding operating method are provided.