Rotor Foil Clearance for Pulp Screening Capacity
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Solution Overview
Problem
Existing screening devices for pulp suspensions face challenges such as limited pulp consistency, energy inefficiency, and operational instability, particularly in handling high consistency pulp suspensions.
Innovation Solution
The screening device features a rotor with a cylindrical body, circular elements, low protrusion foil arms, and detachable foils. The rotor is designed with adjustable foil clearance and a specific distance between the rotor and the screening cylinder, allowing for efficient screening of pulp suspensions with 0-5% consistency, including high consistency pulp.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between the rotor and screening cylinder is reduced to increase screening capacity, then the screening effect is improved, but the risk of fiber accumulation and spinning increases
Solution Approach 1:
The patent applies the dynamics principle by making the foil arms adjustable in length, allowing the system to adapt to different pulp consistencies. The foil arms can be extended or retracted based on operational conditions, enabling the rotor to maintain optimal clearance from the screening cylinder surface. This dynamic adjustment prevents fiber accumulation and spinning while maximizing screening capacity for high consistency pulp suspensions.
2Device complexity
If conventional rotors are used for high consistency pulp suspensions, then the device structure is simple, but energy consumption increases and operational security decreases
Solution Approach 1:
The adjustable foil arms reduce energy consumption by optimizing the rotor-screening cylinder clearance dynamically. For high consistency pulp suspensions, the foil arms can be extended to maintain adequate clearance, preventing fiber accumulation and reducing the energy required to maintain rotational speed and prevent spinning. This dynamic structure achieves operational security while reducing energy consumption compared to fixed-structure rotors.
3Productivity
If the rotor rotates at higher speed to improve screening effect, then productivity increases, but the risk of fiber accumulation and operational failure increases
Solution Approach 1:
The patent applies dynamics by enabling the foil arms to be adjusted in length based on rotational speed and pulp consistency conditions. At higher rotational speeds, the foil arms can be extended to maintain optimal clearance from the screening cylinder, preventing fiber accumulation and spinning. This dynamic adjustment allows the system to operate at higher speeds for improved productivity while maintaining operational security through appropriate clearance management.
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 achieves energy savings, operational security, and increased capacity for screening high consistency pulp suspensions, while minimizing maintenance costs and optimizing the screening effect.
Implementation Method 1
the rotor rotates, the blades produce on the screening surface a pressure pulse on account of which reject pulp and fibers collected onto the screening surface become released from the screening surface and return to the pulp suspension
Implementation Method 2
a cylindrical screening surface equipped with apertures for screening pulp
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The invention relates to a screening device for screening pulp suspensions, which screening device (30) comprises a screening cylinder (20) and a rotor (10) located and rotating inside the screening cylinder (20), in which screening device (30) the screening cylinder (20) is cylindrical and its surface comprises apertures for passing through accept of the pulp suspension during screening, in which screening device (30) the rotor (10) for rotating the pulp suspension in a screening space located between an inner surface of the screening cylinder (20) and an outer surface of the rotor (10) comprises a cylindrical rotor body (12) and a hub (14), in which screening device in the screening space foils (15) are located. The rotor (10) of the screening device (20) comprises circular elements (18) welded or otherwise fixedly attached to the cylindrical rotor body (12) on its outer surface and foil arms (16) formed as low protrusions on the circular elements (18), the foils (15) being detachably attached to the foil arms (16) and the distance between the outer surface of the rotor body (12) and the inner surface of the screening cylinder (20) of the screening device (30) being 45-85 mm, preferably 55 -75 mm.