Electret Fiber Sheet Surface Charge Distribution for Dust Collection
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Solution Overview
Problem
Conventional electret fiber sheets produced by hydrocharging methods fail to achieve dense positive polarity charge distribution, leading to inadequate dust-collecting performance.
Innovation Solution
An electret fiber sheet is produced using a method where jets of water or water droplets are sprayed onto a non-conductive fiber sheet in a misty environment, with a spouting pressure of 0.5 to 6.0 MPa and a nozzle distance of 20 to 100 mm, resulting in an uneven distribution of positive polarity charge denser towards the surface, as measured by spectrophotometric values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrocharging method is used to charge fiber sheet, then electric charge is distributed throughout the fiber sheet, but positive and negative charges are evenly mixed resulting in neutralization and insufficient charging density
Solution Approach 1:
The patent applies local quality by creating different charge distributions in different regions of the fiber sheet. Specifically, the surface region is given positive polarity charge while the inner region contains negative polarity charge, achieving local differentiation that prevents charge neutralization and enhances overall charging density. This is accomplished through controlled water spraying that deposits charges selectively at different depths.
Solution Approach 2:
The patent employs asymmetry by breaking the symmetric even distribution of charges achieved by conventional hydrocharging. Instead of uniform positive-negative mixing throughout, the method creates an asymmetric charge structure with positive charges concentrated at the surface and negative charges in the interior, optimizing both charge density and dust-collecting performance.
2Reliability
If conventional hydrocharging method is used, then production is simple, but charge distribution is uniform resulting in neutralization and poor dust-collecting characteristics
Solution Approach 1:
The patent applies parameter changes by modifying the water spraying parameters (pressure, distance, spray pattern) to control charge deposition. By optimizing these parameters, the method achieves differentiated charge distribution (positive at surface, negative inside) that enhances dust-collecting performance without requiring fundamentally new equipment, only adjusted operational parameters.
3Productivity
If water is sprayed at high pressure to charge fiber sheet, then charging efficiency increases, but charge distribution becomes even more uniform causing neutralization
Solution Approach 1:
The patent resolves this contradiction by using high pressure spraying to achieve different local outcomes: intense surface impact deposits positive charges at the surface, while water penetration delivers negative charges to the interior. This local differentiation maintains high charging efficiency while achieving high overall charge density without neutralization.
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 method achieves a charge distribution significantly different from conventional hydrocharging, resulting in excellent dust-collecting characteristics with positive polarity charge unevenly distributed towards the surface of the fiber sheet.
Implementation Method 1
a method in which a fiber sheet to be used is electretized by impinging on the whole surface of the fiber sheet high pressure water spouted from a nozzle of a so-called water jet punch (WJP)
Implementation Method 2
electret fiber sheets that are formed by densely charging a fiber sheet with electric charge
Data Source
Figure 1
AI summary
Problem: The present invention allows a fiber sheet to be densely charged with electric charge and provides an electret fiber sheet that has excellent dust-collecting characteristics. Solution: The electret fiber sheet according to the present invention is an electret fiber sheet in which the relationship between a* and b* measured by a spectrophotometer when a red positive charge toner and a blue negative charge toner are attached to the sheet satisfies the expression: [12 ≤ {-(b*)-(a*)}Ave ≤ 50].