Centrifugal Air Classifier Flow Channel Internals for Fineness
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Solution Overview
Problem
Centrifugal air classifiers face challenges in achieving high fineness and selectivity due to uneven fluid flow through the classifying wheel blades, leading to blurred separation and reduced throughput, as well as the inability to handle increasing demands for subtleties and energy efficiency.
Innovation Solution
The design incorporates specially shaped flow channels with constriction, widening, and further constriction, and strategically placed internals to stabilize and limit vortices, along with a vane ring that accelerates fluid flow against the classifying wheel, enhancing vortex stability and relative velocities for improved separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the deflector wheel has a relatively large axial extent, then the throughput capacity is increased, but the flow uniformity deteriorates leading to blurred separation
Solution Approach 1:
The patent applies local quality by introducing flow straightening elements at specific locations within the flow channels. These elements are positioned in the radially outer third of the deflector wheel, creating locally improved flow conditions where they are most needed to prevent vortex formation, while allowing the overall wheel to maintain its large axial extent for high throughput capacity.
Solution Approach 2:
The flow channels are segmented into different radial zones, with flow straightening elements installed only in the radially outer third. This segmentation allows different parts of the flow channel to have different flow characteristics - the outer region has stabilized flow while the inner region maintains high velocity for separation, resolving the contradiction between throughput and separation precision.
2Manufacturing precision
If the fluid flow velocity is increased to improve separation fineness, then the separation precision is improved, but the energy consumption increases
Solution Approach 1:
The flow straightening elements perform preliminary action by stabilizing the flow and preventing vortex formation before the fluid reaches the separation zone. This preliminary flow conditioning ensures that the fluid enters the separation region with optimal velocity distribution, achieving high separation fineness without requiring excessive overall flow velocity and thus reducing energy consumption.
Solution Approach 2:
The patent changes the flow parameters locally by introducing flow straightening elements that modify the velocity profile and reduce turbulence in specific regions. This allows the system to achieve the required separation fineness through localized parameter optimization rather than uniformly increasing energy input across the entire system.
3Ease of operation
If flow vortices are allowed to form in the flow channels, then the fluid flow is more turbulent which can enhance mixing, but the separation selectivity deteriorates due to blurred particle trajectories
Solution Approach 1:
The patent converts the potentially harmful effect of vortex formation into a benefit by strategically placing flow straightening elements that harness the natural flow patterns. These elements redirect the flow in a controlled manner, converting what would be chaotic vortices into organized flow structures that maintain separation selectivity while still providing adequate mixing in the dispersion region.
Solution Approach 2:
The flow straightening elements extract or remove the harmful vortex formation from the flow channels by introducing structural features that prevent vortex development. This extraction of the harmful flow pattern allows the system to maintain high separation selectivity while preserving beneficial flow dynamics in other aspects.
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 achieves higher fineness and fines extraction efficiency by stabilizing vortices, reducing turbulence, and increasing relative velocities between the fluid and the classifying wheel, resulting in improved separation quality and reduced energy consumption.
Implementation Method 1
The separating effect of a classifying wheel is based on the fact that the drag force of the fluid and the centrifugal force in the flow channels between the classifying wheel blades of a classifying wheel, the so-called deflector wheel, act in opposite directions on the individual particles of the solid.
Implementation Method 2
The separating effect of a classifying wheel is based on the fact that the drag force of the fluid and the centrifugal force in the flow channels between the classifying wheel blades of a classifying wheel, the so-called deflector wheel, act in opposite directions on the individual particles of the solid.
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
In a centrifugal air classifier with a rotary-driven classifier wheel, through which a classifying fluid flows from the outside to the inside against its rotational direction, and which has ring-shaped classifier blades arranged between retaining discs, forming flow channels between the classifier blades, with internal components influencing the flow pattern arranged within the flow channels, the fineness range of existing air classifiers is to be extended to achieve an even higher level of fineness than before. This is achieved by providing internal components (5) on the radially outer third of the classifier wheel radius on the front side of the classifier blade (3) in the direction of rotation, such that the flow channel (6) between the classifier blades (3) first has a constriction, then a widening, and then another constriction, so that the constrictions limit the classifying vortex formed by the incoming classifying fluid.