Networked Pulp Disturbance for Density and Separation
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Solution Overview
Problem
In separation devices like thickeners, the formation of 'donuts' or agglomerated pulp masses around the rake assembly leads to decreased pulp density, increased torque requirements, and reduced separation efficiency, as well as maintenance issues due to wear and hindered solid collection.
Innovation Solution
Applying a uniform disturbance, such as shear, across an upper region of the networked pulp layer to disrupt the continuous contact between pulp aggregates, releasing entrained liquid and increasing the relative density of the pulp below the disturbance zone, thereby enhancing separation efficiency and preventing donut formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulp aggregates are allowed to settle and form a networked layer without disturbance, then the separation efficiency is improved, but the pulp density decreases and donut formation occurs
Solution Approach 1:
The patent applies periodic or intermittent disturbance to the networked pulp layer rather than continuous disturbance. The disturbance is applied in cycles to disrupt the networked structure and release entrained liquid at specific intervals, thereby increasing pulp density while maintaining separation efficiency by allowing settling to occur between disturbance cycles.
Solution Approach 2:
The patent changes the physical state or structure of the pulp layer by applying disturbance to transition the networked pulp from a low-density aggregated state to a higher-density compacted state. This parameter change in the pulp structure releases entrained liquid and increases relative density without compromising the overall separation process.
2Productivity
If the pulp aggregates are allowed to settle and form a networked layer without disturbance, then the separation efficiency is improved, but donut formation occurs around the rake assembly
Solution Approach 1:
The periodic disturbance prevents the continuous formation of stable donuts around the rake assembly by intermittently disrupting the networked pulp structure. This periodic action breaks up agglomerated masses before they can form persistent donuts, thereby maintaining reliable operation and preventing the maintenance issues associated with donut formation.
3Quantity of substance
If disturbance is applied to the networked pulp layer, then the pulp density increases, but the settling process is disrupted
Solution Approach 1:
By applying disturbance periodically rather than continuously, the patent allows the settling process to occur during non-disturbance intervals. This periodic approach enables the pulp to settle and form networked structures, which are then briefly disrupted to release entrained liquid and increase density, followed by another settling phase. This cycle maintains overall settling efficiency while achieving density increase.
Solution Approach 2:
The disturbance is applied partially to only the networked pulp layer rather than to the entire suspension. This partial action selectively increases density of the settled layer without significantly disrupting the ongoing settling process in the upper zones, thereby maintaining productivity while achieving the density increase goal.
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 method increases the pulp density below the disturbance zone by 5-50% compared to above, improving settling efficiency, reducing maintenance needs, and preventing donut formation, thus enhancing the overall performance of separation devices.
Implementation Method 1
applying a shear profile substantially uniformly across a disturbance zone in an upper region of the networked layer so as to disrupt the networked pulp in the disturbance zone
Implementation Method 2
allowing the pulp aggregates to settle towards the bottom of the tank and form a networked layer of pulp
Data Source
AI summary
The present invention provides a method (20) of separating pulp from a feed material within a tank (1), the method comprising the steps of (23) introducing the feed material (22) into the tank (1); (24) allowing the feed material (22) to settle in the tank (1); (25) allowing the pulp (21) to form into aggregates (13); (26) allowing the pulp aggregates (13) to settle towards the bottom of the tank (1) and form a networked layer (2) of pulp; and (27) causing a disturbance substantially uniformly across a disturbance zone (16) in an upper region of the networked layer (2), so as to disrupt the networked pulp in the disturbance zone within a predetermined period of time; thereby releasing entrained liquid from the networked pulp in the disturbance zone (16) and increasing the relative density of the pulp below the disturbance zone. The invention also provides a separation device (40) for separating pulp (21) from a feed material (22).