Concentric Dual-Screen Filter with Fixed Spiral Wall
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Solution Overview
Problem
Conventional screw press and rotary pressurized type dewaterers face challenges in downsizing while maintaining dewatering performance, leading to increased machine size or costs.
Innovation Solution
The use of two filter media, an inner and outer screen, with the spiral fixed wall not rotating, allows for improved dewatering performance and downsizing by generating a shearing force and simplifying the structure, reducing production costs, and eliminating the need for additional scrapers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional screw press with a single outer screen is used, then the structure is simple, but the dewatering performance is insufficient and the machine size cannot be reduced
Solution Approach 1:
The single outer screen is segmented into two concentric screens (inner screen and outer screen), allowing each screen to contribute to the dewatering process. This segmentation improves dewatering performance while maintaining a relatively compact structure, resolving the contradiction between structural simplicity and dewatering effectiveness.
2Length of moving object
If the outer screen length is shortened for downsizing, then the machine size is reduced, but the dewatering performance deteriorates
Solution Approach 1:
By dividing the filtering function between inner and outer screens, the effective filtering length is doubled without increasing the axial length of the machine. This allows the outer screen to be shorter while maintaining adequate dewatering performance through the combined action of both screens.
Solution Approach 2:
The inner screen is nested within the outer screen, creating a concentric arrangement where both screens work simultaneously. This nested configuration maximizes the filtering surface area within a compact axial space, enabling downsizing while preserving dewatering performance.
3Productivity
If a rotary pressurized type dewaterer is used to improve throughput, then the dewatering capacity increases, but the machine size and cost increase
Solution Approach 1:
The inner screen rotates while the outer screen remains stationary, creating dynamic relative motion between the two screens. This dynamic configuration generates shearing force that enhances dewatering efficiency and throughput without requiring the entire machine to be larger, thus improving productivity while controlling machine size.
4Ease of operation
If a ribbon screw is rotated along with the inner and outer screens, then the cake is conveyed, but the structure becomes complex and maintenance becomes difficult
Solution Approach 1:
The ribbon screw is extracted from the rotating assembly, leaving only the inner screen to rotate. The stationary outer screen and fixed wall structure provide the necessary conveyance function without requiring an additional rotating screw component. This simplifies the structure and improves maintainability while still achieving effective cake conveyance through the differential rotation of the inner screen.
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 enhances dewatering efficiency, reduces machine size, and lowers production costs while maintaining stable filtering performance and improving maintenance properties.
Implementation Method 1
The inner screen and the outer screen are rotated with a difference in rotational speed between the inner screen and the outer screen, which generates a shearing force in the cake moved in the filtering room
Implementation Method 2
While the treated feed fed in the filtering room is spirally moved in the apparatus along the fixed wall, the filtering and thickening are performed by the two filter medias of the inner and outer screens, and the squeezing and dewatering are performed
Data Source
Figure 1
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AI summary
To provide a filtering apparatus and a filtering method, in which dewater performance is improved while downsizing of the apparatus is achieved: The filtering apparatus includes a cylindrical or conical inner screen 1 and an outer screen 2 which are concentrically disposed and a spiral fixed wall 3 which is disposed in a filtering room 4 between the inner screen 1 and the outer screen 2. Only the inner screen 1 and/or the outer screen 2 are/is rotated about a shaft center while the spiral fixed wall 3 is not rotated. During this manipulation process, a treated feed is fed into the filtering room 4 from one end of the filtering room 4, thus treated liquid is filtered through the inner screen 1, and is filtered through the outer screen 2, so that each filtrate is discharged to the outside, and a cake is discharged from the other end of the filtering room 4.