Profile Bar Screen With Integrated Support Shoulders
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Solution Overview
Problem
The installation of profile bar screens in cylindrical digester vessels is time-consuming and costly due to the need for adjusting and replacing support rods, which are not effectively supported by the digester wall, leading to potential screen failure and increased downtime during maintenance.
Innovation Solution
A profile bar screen design with horizontal support arches having integrated support shoulders that rest against the digester wall, allowing for quick installation without altering the pressure vessel wall, and featuring expansion slots for flexibility to accommodate deviations in the cylindrical shape, reducing the need for extensive adjustments and weld inspections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If support rods are used to hold the screen plate against the digester wall, then the screen can be supported, but the support rods are not effectively supported by the deviated wall and may bend or break
Solution Approach 1:
The support structure is segmented into multiple support rods distributed across the screen area, allowing localized adaptation to wall deviations while maintaining overall support integrity. Each support rod can independently accommodate local variations in wall curvature.
Solution Approach 2:
The support rods are made adjustable in length to dynamically adapt to the actual digester wall geometry. This allows the support system to accommodate manufacturing deviations and wall deformations without requiring precise pre-adjustment during installation.
2Reliability
If adjustable support rods are used to accommodate wall deviations, then support reliability improves, but installation becomes time-consuming due to adjusting each individual rod
Solution Approach 1:
The support rods are pre-adjusted to standard lengths during manufacturing, eliminating the need for individual adjustment during installation. The system is designed to work with these standard lengths even when accommodating wall deviations through the segmented distribution of supports.
Solution Approach 2:
The support system accommodates wall deviations by changing the effective support parameters (rod lengths, positions) through selective replacement rather than adjustment, maintaining standardization while adapting to geometric variations.
3Reliability
If a frame bed is used to support the profile bar screen, then support is obtained, but the frame bed may obstruct withdrawal flow and accumulate deposits
Solution Approach 1:
Instead of a continuous frame bed, the support structure is segmented into discrete support rods, creating gaps that allow withdrawal flow to pass through unobstructed while still providing adequate support for the screen.
Solution Approach 2:
The frame bed structure is extracted and replaced with individual support rods, removing the obstructions caused by continuous framing while retaining the essential support function.
4Adaptability or versatility
If multiple support rods are used to accommodate wall curvature, then support coverage improves, but the complexity of adjusting and inspecting each rod increases
Solution Approach 1:
Standardized support rods with uniform dimensions and adjustment mechanisms are used throughout the system, allowing for simplified inspection and replacement procedures. The repetition of identical components reduces the complexity of maintenance despite the large number of supports.
Data Source
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AI summary
The invention relates to an improved profile bar screen for draining treatment liquor from a suspension of comminuted cellulose material and treatment liquor in an essentially cylindrical digester vessel. According to the invention is a profile bar screen designed with horizontal support arches11 with integrated support shoulders12only at the outer ends of the support arch which support shoulders rest against the inside of the vessel wall 1.The invention combines the techniques from self- supporting screens with support members of weaker screen designs, avoiding need to make any additional welds in the classified pressure vessel wall of the digester. Installation of new screens in compartments previously equipped with blind plates in checkered screen rows may be done quickly and at less costs during shorter down time of digester.