Refiner Segment Bar Weakening Sections for Steam Venting
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Solution Overview
Problem
Conventional refiner segments with bars and dams for lignocellulosic material refinement suffer from steam trapping in box-shaped regions, leading to pressure buildup and damage to dams, which disrupts material flow and reduces refining efficiency.
Innovation Solution
Incorporating bar weakening sections within the box-shaped regions allows trapped steam to escape, reducing the risk of dam damage and maintaining efficient material flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bars and dams are arranged to create box-shaped regions for material flow control, then material flow control is improved, but steam becomes trapped leading to pressure buildup and dam damage
Solution Approach 1:
The bar structure is segmented by introducing weakening sections that divide the continuous bar into sections with controlled openings. These openings create steam escape channels while maintaining the overall box-shaped region structure for material flow control. The segmentation allows steam to escape through the weakening sections without compromising the dam integrity or material flow control function.
Solution Approach 2:
The bar structure has different properties in different locations: the main bar body maintains full strength for structural support and material flow control, while the weakening sections create localized openings for steam escape. This local differentiation allows the bar to simultaneously provide both structural integrity and steam venting functionality without compromising either aspect.
2Reliability
If dams are made robust to prevent steam damage, then dam integrity is improved, but the refining efficiency decreases due to restricted material flow
Solution Approach 1:
The bar is segmented with weakening sections that create controlled openings for steam escape. This segmentation allows steam to vent without requiring the dam to be made more robust, thereby maintaining dam integrity while preventing steam pressure buildup that would otherwise restrict material flow and reduce refining efficiency.
Solution Approach 2:
The weakening sections act as intermediary structures that mediate between the steam pressure and the dam. Instead of steam directly attacking the dam, the weakening sections provide an intermediate escape path, reducing the force exerted on the dam while maintaining material flow through the box-shaped regions.
3Object-generated harmful factors
If bar weakening sections are introduced to allow steam escape, then steam evacuation is improved, but the structural strength of the bar decreases
Solution Approach 1:
The bar has different local properties: the main body maintains full structural strength for support and flow control, while the weakening sections create localized openings for steam escape. The weakening sections are strategically positioned to provide steam venting while the remaining bar material maintains sufficient strength for its structural function.
Solution Approach 2:
Instead of completely removing the bar or making it fully robust, the weakening sections provide partial openings that are sufficient for steam escape but do not compromise overall bar strength. This partial action approach allows steam evacuation while maintaining adequate structural integrity.
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
The solution effectively reduces the risk of dam damage, prolongs the usable life of refiner segments, and maintains consistent refining efficiency by allowing steam to escape without compromising the disc gap pressure, thus ensuring controlled material flow and extended equipment lifespan.
Implementation Method 1
steam may get caught there. Due to the fact that the steam is trapped in the region the pressure will build up over time... The high pressure steam will constantly bombard the surfaces of the box shaped region until it finally may escape through a created hole in the surface
Implementation Method 2
the refining or defibration action will cause friction which in turn will heat up the processed material. Since lignocellulosic material, e.g., wood pulp, naturally contains water the friction will heat up the water and steam will be created
Implementation Method 3
the friction will heat up the water and steam will be created
Data Source
AI summary
A refiner segment for a refiner of lignocellulosic material includes a first bar, a second bar, a first dam, and a second dam. The first bar has a width and includes a first bar weakening section. The first bar weakening section includes two planar faces defining a wedge-shaped recess with a tip and a base. The two planar faces meet at the tip. The tip is separated from the base by a depth. The depth is greater than or equal to half of the width and less than or equal to the width. The first dam extends between the first bar and the second bar. The second dam extends between the first bar and the second bar. The first bar, the second bar, the first dam, and the second dam define a first essentially box-shaped region. The first bar weakening section is positioned within the first essentially box-shaped region.