Refiner Plate Pre-Dam for Wear Reduction and Energy Efficiency
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Solution Overview
Problem
Refiner plates with full-height dams in disc-type refiners experience significant wear and high energy consumption due to abrupt and uncontrolled flow of lignocellulosic material, leading to compromised fiber quality and reduced useful lifetime.
Innovation Solution
Incorporating a pre-dam with a height less than the main dam, positioned in front of the main dam, to gradually change the flow direction and reduce wear on the main dam, thereby improving flow distribution and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-height dams are used to force material flow out of grooves, then flow restriction is achieved, but wear on dams increases significantly
Solution Approach 1:
The dam structure is segmented into two distinct parts: a pre-dam with lower height and a main dam with full height. This segmentation allows the pre-dam to handle the initial impact of material flow, reducing wear on the critical main dam while maintaining effective flow restriction. The pre-dam acts as a sacrificial element that protects the main dam from direct perpendicular collision.
Solution Approach 2:
The pre-dam performs a preliminary action by intercepting and redirecting material flow before it reaches the main dam. This preliminary flow redirection reduces the velocity and angle of impact on the main dam, thereby reducing wear while still achieving the necessary flow restriction function.
2Productivity
If full-height dams are used to force material flow out of grooves, then flow restriction is achieved, but energy consumption increases
Solution Approach 1:
The segmented dam structure with pre-dam and main dam creates a two-stage flow redirection process that is more energy-efficient. The pre-dam gradually redirects flow at a lower angle, reducing the abruptness of the maneuver and thereby reducing the energy required to force material out of the groove and into the refining gap.
Solution Approach 2:
The pre-dam creates a more dynamic and gradual flow transition, allowing material to be redirected progressively rather than abruptly. This dynamic approach reduces the force required for flow restriction, thereby reducing energy consumption while maintaining productivity.
3Productivity
If full-height dams are used to force material flow out of grooves, then flow restriction is achieved, but flow distribution deteriorates
Solution Approach 1:
The segmented dam structure improves flow distribution by creating a more controlled and progressive flow transition. The pre-dam redirects flow at a reduced angle, creating a smoother distribution pattern that avoids the abrupt and uncontrolled flow patterns caused by full-height dams alone.
Solution Approach 2:
The pre-dam performs a preliminary flow redirection that prepares the material flow for a smoother transition into the refining gap. This preliminary action at a lower angle creates a more uniform and controlled flow distribution, improving the quality of fiber separation.
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 pre-dam arrangement reduces wear on the main dam, decreases energy consumption, and enhances fiber quality by providing a smoother and more controlled flow distribution.
Implementation Method 1
As at least one of the refiner plates rotates, centrifugal forces created by the relative rotation between the two refiner plates move the lignocellulosic material outwards and towards the periphery of the refiner plates
Data Source
AI summary
The invention relates to a refiner plate segment in a refiner plate for mechanically refining of lignocellulosic material in a refiner, said refiner plate segment comprising at least a first, generally radially extending bar, a second, generally radially extending bar, a groove arranged and defined between said first, generally radially extending bar and said second, generally radially extending bar, and a main dam, which has a height H and is arranged in the groove, wherein a pre-dam is arranged in front of the main dam, said pre-dam has a height h which is less than the height H of the main dam.