Conical Pulp Screen Rotor Layout for Low-Wear Deflaking
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Solution Overview
Problem
Disc-type pulp screens suffer from high power consumption, rapid wear, and require large machine sizes due to uneven wear patterns and limited screen area, while conventional in-flow screens are unsuitable for immediate coarse screening due to impurity tangling and accumulation.
Innovation Solution
A pulp screening machine with a basket-type screen and rotor vanes outside the screen, utilizing a conical design with angled projecting strips or grooves to enhance de-flaking and reduce wear, and an in-flow principle to remove coarse heavies externally, allowing for flexible rotor vanes and improved throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If disc-type screens with flat screen plate and high rotor tip speed are used, then de-flaking efficiency is improved, but power consumption increases and wearing accelerates
Solution Approach 1:
The patent inverts the conventional disc-type screen design by placing the rotor inside the screen instead of outside. This inversion allows the rotor to operate at lower tip speeds while maintaining effective de-flaking, significantly reducing power consumption. The inverted configuration also improves screening efficiency by allowing better contact between rotor vanes and fiber suspension.
Solution Approach 2:
The patent changes the operational parameters by reducing rotor tip speed from high values in conventional disc screens to lower values in the inverted design. This parameter change maintains de-flaking efficiency while dramatically reducing power consumption and mechanical stress on components.
2Productivity
If disc-type screens with high rotor tip speed are used, then de-flaking efficiency is improved, but wearing of rotor and screen plate accelerates
Solution Approach 1:
By inverting the design and placing the rotor inside the screen, the patent reduces rotor tip speed and consequently reduces centrifugal forces. This inversion protects both the rotor and screen from rapid wearing while maintaining effective de-flaking through the inverted vane configuration.
Solution Approach 2:
The patent converts the potentially harmful high centrifugal forces into a benefit by using the inverted rotor design to generate controlled fluid dynamics that enhance screening efficiency while reducing mechanical wear on components.
3Productivity
If flat screen plate is used, then de-flaking efficiency is improved, but machine size increases due to limited screen area
Solution Approach 1:
The patent replaces the flat screen plate with a curved or conical screen surface. This curvature increases the effective screening area within a compact volume, allowing high de-flaking efficiency to be achieved in a smaller machine footprint. The curved surface also improves fiber suspension distribution across the screen.
4Stability of the object's composition
If rotor vanes are connected with rings to ensure position stability, then rotor stability is improved, but impurity tangling and accumulation occurs
Solution Approach 1:
The patent extracts the rings that connect rotor vanes in conventional designs. By removing these rings, the inverted rotor design eliminates impurity tangling and accumulation points while maintaining adequate rotor stability through the inverted vane mounting configuration.
Solution Approach 2:
By inverting the rotor design and changing how vanes are mounted and supported, the patent achieves position stability without requiring external connecting rings that would create impurity accumulation zones.
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
Reduces power consumption and wear, increases screen area efficiency, and enables effective coarse screening with minimal fiber loss by enhancing de-flaking and impurity removal, suitable for immediate post-pulping applications.
Implementation Method 1
reduces wearing to the screen inside due to the centrifugal forces. Therefore, the coarse heavies, which will cause severe wearing to the screen, will no longer stay inside the screen.
Implementation Method 2
The rotor vanes are designed with a matched shape respectively so that it can sweep over the surface of the screen. According to the invention the screen angle α between the screen of the pulp screening machine and the horizontal plane is greater than or equal to 45°, and less than 90°.
Data Source
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AI summary
The invention relates to a pulp screening machine comprising screen (200) which extends upwards from the bottom of the pulp screening machine and a rotor (100) which rotates around the outside of the screen, wherein the accept outlet is provided inside the screen (200) and the pulp outlet and reject outlet are provided outside of the screen (200), wherein the rotor vanes (101) of the rotor (100) cantileveredly extends from the rotor base (102) on top of the screen (200) into the region of the screen (200), with the rotor vanes (101) not being connected to each other in the region of the screen (200), wherein the rotor vanes have a rigidity adaptable for deflaking in corporation with the outside surface of the screen.