Pressure Screen Dilution Water Rejection Control
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Solution Overview
Problem
Pressure screens experience thickening effects that limit capacity and increase energy consumption due to inconsistent material density, with existing dilution methods either being inefficient or costly, particularly when dilution water exceeds 40% of the reject flow, leading to motor overload and reduced effectiveness.
Innovation Solution
A method where dilution water is added to the reject area in amounts ranging from 0.8 to 3.5 times the reject flow volume, with a rotor design featuring ribs or protruding structures to enhance distribution, allowing for continuous and cost-effective dilution without compromising screen operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dilution water is added to the reject area to reduce thickening, then the consistency in the reject room is reduced, but the motor load increases due to reject flow restriction in the screening zone
Solution Approach 1:
The patent applies local quality by introducing dilution water at specific locations (reject area) rather than uniformly throughout the system. The dilution water is added locally to the reject area where it is most needed to reduce consistency, while the screening zone maintains its own flow characteristics without additional water addition, thus avoiding unnecessary motor load increase.
Solution Approach 2:
The patent changes the parameter of dilution water amount from conventional ranges (20-40% of reject flow) to a higher range (40-70% of reject flow). This parameter change allows the system to achieve better consistency reduction in the reject area while the optimized flow distribution ensures that the additional water does not cause excessive motor load increase.
2Stability of the object's composition
If dilution water amount is increased above 40% of reject flow to reduce consistency further, then the thickening effect is reduced, but the water flows via short cut to reject outlet instead of entering screening zone, causing screen overloading
Solution Approach 1:
The patent applies preliminary action by pre-introducing dilution water into the reject area before the material reaches the screening zone. This preliminary dilution action reduces the consistency of the reject material in advance, preventing it from causing thickening effects in the screening zone during normal operation.
Solution Approach 2:
The patent uses the reject area as an intermediary zone between the screening zone and the final reject outlet. By adding dilution water in this intermediary reject area, the system creates a buffer that allows consistent material to be diluted without directly impacting the screening zone flow, thus preventing screen overloading while maintaining productivity.
3Stability of the object's composition
If dilution water is added directly into the screening zone to reduce thickening, then the consistency in the screening zone is reduced, but the structure becomes complicated and costly
Solution Approach 1:
The patent applies the taking out principle by extracting the dilution function from the screening zone and relocating it to the reject area. Instead of adding water directly in the screening zone (which would require complex piping and structures), the system adds water in the reject area where the structure is simpler and already exists, thus reducing device complexity while achieving the same consistency reduction effect.
Solution Approach 2:
The patent uses a simple, inexpensive dilution water adding apparatus in the reject area rather than investing in complex, expensive direct screening zone injection systems. The solution prioritizes cost-effective implementation using readily available components and simple addition points in the reject area, avoiding the need for elaborate water delivery infrastructure.
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 approach reduces reject rate, lowers power consumption, and decreases the risk of plugging, achieving stable operation with reduced energy usage and lower operational costs while maintaining effective screening performance.
Implementation Method 1
all of them in common focus on creating pressure and suction pulses towards the screening surface
Implementation Method 2
creating pressure and suction pulses towards the screening surface
Implementation Method 3
adding dilution water into the reject area... the amount of the dilution water added into the reject area is 0.8 to 3.5 times by volume
Implementation Method 4
dilution water is added as widely used at the reject area... the thickening factor keeps decreasing
Data Source
AI summary
A method for dilution for a pressure screen comprising a rotor rotating inside a screen a distance to the screen, includes supplying feeding stock into a screening zone formed in the spacing between the rotor and the screen with some of the feeding stock passing through the screen into an accept area to become accept, and the remaining feeding stock discharged into a reject area as reject flow. The amount of the dilution water added into the reject flow is 0.8 to 3.5 times the amount of the reject flow by volume. Additionally, a pressure screen comprises a dilution water adding apparatus adapted to add dilution water directly into the reject area of the pressure screen, wherein the amount of the dilution water added into the reject flow is 0.8 to 3.5 times of the amount of the reject flow by volume.