Oblique Anti-Rewet Inserts for Pulp Press Roll Filtrate Control
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Solution Overview
Problem
Existing pulp washing and dewatering technologies face challenges with rewetting issues due to filtrate flowback, which complicates the process and increases costs, especially when trying to retrofit existing equipment with baffle plates or inserts that are difficult to install and manufacture.
Innovation Solution
The solution involves a rotatable press roll design with circumferential frame rings and oblique anti-rewet inserts with inner and outer holes, which prevent filtrate flowback by using the rotational direction of the press rolls to lift and direct filtrate inward, reducing the need for extensive welding and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If baffle plates are inserted into filtrate channels to prevent rewetting, then rewetting is prevented, but insertion and removal become difficult due to friction
Solution Approach 1:
The baffle plate is divided into two separate parts: a first part inserted into the filtrate channel and a second part attached to the outer surface of the press roll. This segmentation allows each part to be independently installed and removed, significantly reducing friction and making maintenance operations much easier while maintaining effective rewetting prevention.
Solution Approach 2:
The baffle plate configuration transitions from a single-plane structure to a three-dimensional arrangement with parts extending in different directions (one part inside the channel, another part on the outer surface). This dimensional change enables the baffle to effectively block rewetting flows while creating clearance for easier installation and removal.
2Reliability
If existing press rolls are retrofitted with baffle plates, then rewetting prevention is achieved, but the procedure becomes complicated and expensive
Solution Approach 1:
By segmenting the baffle plate into removable parts, the retrofit process becomes simpler and less expensive. The first part can be inserted into existing filtrate channels without modifying the press roll structure, while the second part attaches to the outer surface, avoiding complex welding or permanent modifications to existing equipment.
Solution Approach 2:
The segmented baffle plate design uses simpler, less expensive materials and construction methods compared to traditional welded baffle plates. The parts can be manufactured more economically and installed without expensive retrofitting procedures, making the solution cost-effective for existing press rolls.
3Reliability
If the transverse extension of insert member corresponds to the inner cross-section of the filtrate channel, then rewetting is prevented, but insertion becomes difficult due to friction and end structure limitations
Solution Approach 1:
The insert member is segmented into a first part that fits within the filtrate channel cross-section and a second part that extends to the outer surface. This segmentation reduces the insertion friction by distributing the contact area and allows the insert to navigate end structure limitations more easily while maintaining effective rewetting prevention.
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 reduces rewetting, enhances stability and strength, and allows for easier installation and maintenance, improving the efficiency and longevity of pulp washing and dewatering equipment while maintaining high performance.
Implementation Method 1
the rotational direction of the press rolls to lift and direct filtrate inward
Data Source
Figure 1~2
Figure 3a~3b
Figure 4
AI summary
The invention is related to an apparatus for washing and/or dewatering pulp, the apparatus comprising two rotatable press rolls (202, 204) with a nip (238) between, each press roll (202, 204) including an axis (203, 205), a mantle element (206, 208) with permeable outer and inner surfaces, an axial inner drum (222, 224), and radial walls (226, 228, 230, 232) arranged between the mantle element (206, 208) and the axial inner drum (222, 224), so that axial filtrate channels (210, 212) are created between the mantle element (206, 208), the axial inner drum (222, 224) and the radial walls (226, 228, 230, 232), which filtrate channels (210, 212) are arranged to receive filtrate from the pulp. According to the invention, each press roll (202, 204) is arranged to rotate with a direction of rotation (R1, R2), so that the pulp is arranged to be fed upwards through the nip (238); and in that at least one filtrate channel (210, 212) is provided with an oblique wall (241) between a radial wall (226, 228, 230, 232) and the mantle element (206, 208), which oblique wall (241) points in the same direction as the direction of rotation (R1, R2) to prevent the flow of liquid from the filtrate channel (210, 212) to the outer surface of the mantle element (206, 208).