Pivotable Side Casing Members for Pulp Press Roll Maintenance
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Solution Overview
Problem
Existing apparatuses for washing and dewatering pulp have limited accessibility for maintenance work, such as cleaning and replacing press rolls, due to restricted access to the press rolls and nip areas, which complicates inspections and increases the risk of pulp jamming and damage to components.
Innovation Solution
The apparatus features pivotable side casing members with rotation axes closely aligned in a horizontal plane, allowing for increased coverage of the press rolls' outer surfaces and reduced risk of pulp jamming, along with a stationary base unit that balances forces, reducing material usage and installation complexity, and eliminating the need for a central movable casing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vat encloses a large portion of the circumference of the perforated outer surface of the press roll, then the structural integrity and containment are improved, but the accessibility to the press roll for maintenance work deteriorates
Solution Approach 1:
The vat is divided into multiple segments including a first vat segment, second vat segment, third vat segment, and fourth vat segment that can be opened independently. This segmentation allows maintenance personnel to access the press rolls while the remaining vat segments remain in place, maintaining structural integrity during operation and enabling easy access during maintenance.
Solution Approach 2:
The vat segments are designed to be movable between closed and open positions. The first and second vat segments can be opened to provide access to the press rolls, while the third and fourth vat segments can be opened from the opposite side. This dynamic capability allows the structure to transition between providing containment and providing access as needed.
2Ease of repair
If pivotable vat segments are used to provide access to press rolls, then accessibility for maintenance work is improved, but the device complexity increases
Solution Approach 1:
The vat is segmented into four distinct sections with each segment having its own opening mechanism. This segmentation distributes the complexity across multiple simpler units rather than requiring one complex movable structure, making the overall system more manageable and easier to maintain.
Solution Approach 2:
The access function is extracted from the main vat structure by providing separate opening mechanisms for each vat segment. This allows the vat to maintain its primary containment function while providing access capability through independent segments that can be opened without affecting the entire structure.
3Reliability
If the rotation axes of the press rolls are positioned to minimize pulp jamming, then the risk of pulp jamming is reduced, but the coverage of the press rolls by the vat segments changes
Solution Approach 1:
The press rolls are positioned asymmetrically relative to the vat segments, with the rotation axes located such that the press rolls extend beyond the vat enclosure on the sides. This asymmetric arrangement creates clearance zones that prevent pulp jamming while the vat segments can still provide adequate coverage and containment where needed.
Solution Approach 2:
The solution moves the press rolls to a different spatial arrangement where their rotation axes are positioned to create clearance in the horizontal dimension, allowing pulp to pass without jamming while the vat segments provide vertical containment and access when opened.
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 enhances accessibility for maintenance tasks, reduces the risk of pulp jamming, and lowers production and installation costs by using less material and minimizing the apparatus's bulkiness, while maintaining structural integrity and operational efficiency.
Implementation Method 1
each side casing member being pivotable about a rotation axis for providing access to respective press roll
Implementation Method 2
the pulp is pressed in the roll nip, or the press nip, between the press rolls, whereby liquid is pressed out of the pulp
Implementation Method 3
the press rolls having a permeable outer surface, between which the pulp is pressed
Data Source
Figure 1
Figure 2
AI summary
An apparatus for washing and dewatering pulp comprising a first and a second rotatable press roll (102, 104) having a permeableouter surface (106, 108), and a casing comprising a vat (114, 116, 118) in which the press rolls (102, 104) are installed, the press rolls (102, 104) defining a press nip (112) between them, in which press nip (112) the pulp is pressed. The vat (114, 116, 118) com- prises a first side vat segment (114) which partly encloses the outer surface (106) of the first press roll (102) and a second side vat segment (116) which partly en- closes the outer surface (108) of the second press roll (104). The casing comprises a first side casing member (115, 215) provided with the first side vat seg- ment (114) and a second side casing member (117, 217) provided with thesecond side vat segment (116). The side casing members (115, 117, 215, 217) being piv- otable about a first and a second rotation axis(121, 123), respectively, and mov- able between a closed position and an opened position for providing access to the press rolls (102, 104). The distance between the first rotation axis(121) and the second rotation axis(123) is less than the sum of the outer diameter of the first press roll (102) and the outer diameter of the second press roll (104).