Tribocharger Grating for Fiber–Granule Electrostatic Separation
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Solution Overview
Problem
Existing separation installations are inefficient for heterogeneous mixtures containing fibers and granules, as fibers float above granules, leading to insufficient electrostatic charging and damage to conveyor belts, and are prone to fouling.
Innovation Solution
A separation installation with a tribo-electric loading device and containment wall with a grid, where components are tribo-electrically charged within an enclosure, exposed to a separating electric field, and released through a grid when sufficiently charged, ensuring effective separation of fibers and granules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fluidized bed with conveyor belt electrodes is used to separate granule mixtures, then separation effectiveness is improved for homogeneous granules, but separation efficiency deteriorates significantly when the mixture contains heterogeneous components such as fibers and granules
Solution Approach 1:
The invention divides the separation process into two distinct functional zones: a charging zone where triboelectric charging occurs, and a separation zone where electric field separation takes place. This segmentation allows each zone to be optimized for its specific function, enabling effective separation of heterogeneous mixtures containing both fibers and granules
Solution Approach 2:
The invention extracts the charging function from the separation process by using a dedicated triboelectric charging section that is separate from the electric field separation zone. This extraction allows the charging mechanism to be optimized independently, ensuring sufficient charging of all particle types before separation, thereby improving overall separation efficiency for heterogeneous mixtures
2Reliability
If conveyor belts are used as electrodes in the separation installation, then electrostatic separation can be achieved, but the conveyor belts are vulnerable to fouling and damage from trapped charged components
Solution Approach 1:
The invention extracts the electrode function from the conveyor belt system by using fixed electrodes in the separation zone, eliminating the moving conveyor belts that were prone to fouling. This extraction removes the vulnerability while maintaining the electrostatic separation capability
Solution Approach 2:
The invention introduces an intermediary air gap between the charging zone and separation zone, allowing charged particles to be transported through the air rather than requiring direct contact with conveyor belts. This intermediary transport mechanism eliminates the fouling issue while maintaining particle transport and separation functionality
3Adaptability or versatility
If fibers are present in the mixture, then the mixture becomes more heterogeneous, but fibers float above granules in the fluidized bed leading to insufficient electrostatic charging
Solution Approach 1:
The invention applies local quality by creating a specific charging environment in the triboelectric charging zone where all particles regardless of density are subjected to intense frictional charging. This localized charging approach ensures that even lightweight fibers receive sufficient charge before entering the separation zone, achieving uniform electrostatic charging across heterogeneous mixture components
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 almost systematic separation of fibers and granules with high efficiency and reliability, minimizing residues and losses, and reducing wear on components.
Implementation Method 1
impart to the components of said mixture, by tribo-electric action, electrostatic charges which are of opposite polarities
Implementation Method 2
generate in the air gap an electric field, called a 'separating electric field', which is intended to direct the charged components, according to their polarity
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to an installation intended to separate the components of a mixture containing fibres (2) and granules (3), the installation comprising a tribocharger (4) for conferring an electrostatic charge upon the components (2, 3), at least one pair of electrodes (5, 6) for generating a separating electric field that conveys the charged components, according to their polarity, to collectors (10, 11), the installation being characterized in that the tribocharger (4) has a confinement grating (14) designed to keep the components in the tribocharger (4) until the components (2, 3) have attained sufficient charge, and then allow the components, once charged, to pass into the gap (7) from where the components (2, 3) reach their collector (10, 11) under the action of the separating electric field.