Pressure Screen Rotor Annular Gap Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pressure screens for cleaning fibrous stock suspensions face high energy consumption and clogging issues due to inefficient design.
Innovation Solution
The pressure screen features a rotor with decreasing annular gap and radial expansion of rotor blades from the suspension inlet to the reject outlet, along with recesses and offset rotor blades, and a cylindrical design with the rotor located within the screen element, which reduces energy consumption and clogging risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the annular gap between rotor and screen element is reduced, then the flow rate increases and clogging is counteracted, but the energy consumption increases
Solution Approach 1:
The annular gap is designed with varying width along the axial direction, creating different local flow conditions. The gap width decreases from inlet to outlet, providing increasing flow velocity and clogging resistance in regions where it is most needed, while avoiding uniformly high energy consumption throughout the entire rotor.
Solution Approach 2:
The rotor blades are designed with varying radial expansion along the axial direction, creating a dynamic flow pattern. This progressive change in blade geometry optimizes the balance between flow rate enhancement and energy input, allowing the system to adapt flow characteristics along the processing path.
2Ease of manufacture
If the rotor blades have constant radial expansion, then the manufacturing is simpler, but the energy consumption is higher and clogging risk increases
Solution Approach 1:
The rotor blades exhibit varying radial expansion along the axial direction, with different expansion characteristics in different regions. This local variation optimizes energy distribution and flow characteristics, reducing overall energy consumption while maintaining manufacturing feasibility through standardized blade sections.
3Ease of manufacture
If the rotor blades are uniformly distributed, then the manufacturing is easier, but the clogging resistance is reduced
Solution Approach 1:
The rotor blades are offset from one another in the circumferential direction rather than being uniformly distributed. This asymmetric arrangement creates varied flow paths that prevent suspension accumulation in specific zones, significantly improving clogging resistance while maintaining manufacturing simplicity through consistent blade geometry.
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 design effectively counteracts clogging and reduces energy requirements by increasing flow rate and optimizing the rotor blade configuration, enhancing the overall efficiency and functionality of the pressure screen.
Implementation Method 1
the wing element gives off a pressure impulse at the front and a suction impulse behind it on the sieve to be cleared
Implementation Method 2
The flow rate, which increases with the smaller annular gap, counteracts clogging very effectively
Implementation Method 3
the fibrous suspension is rotated more and more by the rotor as the distance from the suspension inlet increases
Data Source
Figure 1~2
AI summary
The invention relates to a pressure screen for cleaning a fibrous stock suspension having a screen element (2) which is of rotationally symmetrical configuration about a screen axis (1) and divides the pressure screen into an inlet chamber (3) and an accepted stock chamber (4), wherein the inlet chamber (3) is connected at one axial end to a suspension inlet (5) and at the opposite axial end to a reject outlet (6), and the accepted stock chamber (4) is connected to an accepted stock outlet (7), and a rotor (8) with rotor vanes (9) is situated in the inlet chamber (3), the rotational axis (10) of which rotor (8) corresponds to the screen axis (1), and which rotor (8) rotates relative to the screen element (2), wherein the rotor vanes (9) are arranged distributed over a plurality of circumferential planes (11) of the rotor (8) which run perpendicularly with respect to the rotational axis (10). Here, the energy consumption and the risk of clogging can be reduced by virtue of the fact that the width of the annular gap (12) between the rotor (8) and the screen element (2) decreases from the suspension inlet (5) to the reject outlet (6). (Figure 1)