Classifier Swirl Suppression for Low Pressure Loss Separation
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Solution Overview
Problem
Conventional classifiers in coal-fired boiler apparatuses suffer from high mixing rates of coarse particles in fine particle products due to circulating swirl flows, which can lead to inefficient separation and increased risk of particle concentration-related issues like firing, and elongating the downward flow forming member to improve separation results in higher pressure loss and reduced efficiency.
Innovation Solution
A classifier design incorporating a rotating fin, a tubular downward flow forming member, and a bowl-shaped recovery cone, with a circulating swirl flow development suppressing portion formed by a slant member or bent housing section to prevent the generation and development of circulating swirl flows, optimizing the ratio of dimensions and angles to enhance particle separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the downward flow forming member is elongated to improve particle separation, then the separation efficiency is improved, but the pressure loss increases and efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the harmful circulating swirl flow from the system by introducing a swirl flow suppressing portion. This removes the adverse effect that caused the need for elongation, allowing effective separation without the penalty of increased pressure loss.
Solution Approach 2:
The patent converts the harmful circulating swirl flow into a beneficial controlled flow pattern. By suppressing the swirl flow, the system achieves better separation efficiency while reducing pressure loss, turning a previously harmful phenomenon into a controlled and beneficial flow condition.
2Quantity of substance
If the circulating swirl flow is allowed to develop, then the coarse particles can be separated, but the mixing rate of coarse particles in fine particle products increases
Solution Approach 1:
The patent segments the flow path into distinct regions: an outer peripheral region where coarse particles are separated by suppressed swirl flow, and an inner region where fine particles proceed to the product outlet. This segmentation prevents mixing between coarse and fine particles, achieving both separation and sharp grain size distribution.
Solution Approach 2:
The patent applies different flow conditions to different regions: the outer peripheral region experiences suppressed swirl flow for coarse particle separation, while the inner region maintains smooth flow for fine particle transport. This local differentiation of flow quality enables simultaneous achievement of separation and product purity.
3Manufacturing precision
If the downward flow forming member is made longer, then the pressure loss increases, but the separation performance improves
Solution Approach 1:
The swirl flow suppressing portion acts as an intermediary element that modifies the flow pattern between the upward flow and the downward flow forming member. This intermediary structure enables effective separation with a shorter downward flow forming member, improving system efficiency while maintaining separation performance.
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
The classifier effectively reduces the mixing rate of coarse particles in fine particle products, achieving a sharp grain size distribution while maintaining low pressure loss, thereby stabilizing the production of fine particles and reducing the risk of particle concentration-related issues.
Implementation Method 1
a strong swing motion is applied at a time of reaching the rotating fins 21 rotating at a predetermined rotating speed around the rotating shaft 22, and a force flipping the particles to an outer side of the rotating fins 21 is applied to the particles in the solid and gas two-phase flow 52 on the basis of a centrifugal force
Implementation Method 2
The solid and gas two-phase flow 52 coming up from the crushing portion ascends to the below of the upper surface plate 40 on the basis of an inertia force
Implementation Method 3
a great circulating swirl flow 14 is generated in a region Y between the downward flow forming member 13 and the housing 41
Data Source
AI summary
A classifier capable of stably providing particles by further reducing the mixing ratio of coarse particles including a rotating fin (21) classifying solid particles by a centrifugal force, a cylindrical downward flow forming member (13) installed on the outer peripheral side of the rotating fin (21), a recovery cone (11) disposed under the rotating fin (21) and the downward flow forming member (13), and a housing (41). A contraction flow area (16) is formed between the housing (41) and the recovery cone (11), and a two-phase flow (52) formed of the mixture of the solid particles and gases blown up through the contraction flow area (16) is collided with the downward flow forming member (13) on the upper side of the housing (41) to form it in a downward flow. Then, that flow is led to the rotating fin side, classified into the fine particles and the coarse particles, and the fine particles are carried together with an airstream, passed through the rotating fin (21), and removed. A circulating swirl flow development suppressing part (30) is installed at the upper part of the contraction flow area (16) and on the outer periphery of the downward flow forming member (13).