Plastic Refiner Suction Cleaning System
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Solution Overview
Problem
Current plastic recycling technologies face challenges in efficiently cleaning plastic snippets due to high energy consumption and poor pumpability of suspensions with low consistency, particularly with materials like plastic films that tend to float or sink, leading to inefficient cleaning and increased energy use.
Innovation Solution
A device and method utilizing a water pump to create a tangential water jet that generates a suction effect in the working gap of a refiner, allowing for high solids consistency during cleaning while maintaining low consistency for easy conveyance, eliminating the need for a pump sump and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If low consistency suspension is used in disc refiner, then pumpability is improved, but cleaning effect deteriorates due to lower friction in working gap
Solution Approach 1:
The patent applies hydraulic principles by using a water jet system to create negative pressure (suction) in the working gap. Water is injected tangentially through a nozzle into the working gap, creating a hydraulic suction effect that draws material through the refiner without requiring atmospheric pressure operation or large pump sumps, thus maintaining good pumpability while enabling effective cleaning.
Solution Approach 2:
The patent changes the pressure parameter in the working gap by introducing a water jet that creates negative pressure (suction). This allows the system to operate with controlled consistency levels - not too high to lose pumpability, not too low to lose cleaning effect - by dynamically adjusting the suction pressure through the water injection rate and nozzle positioning.
2Productivity
If high solids consistency is used in working gap, then cleaning efficiency is improved, but pumpability deteriorates due to high viscosity
Solution Approach 1:
The hydraulic suction system allows high solids consistency material to be drawn into and through the working gap without requiring the suspension to be pumpable at that consistency level. The water jet creates negative pressure that pulls the high-consistency material through the refiner, eliminating the need for the material to flow under its own weight or be pumped at high consistency.
Solution Approach 2:
The patent segments the consistency requirement into two distinct zones: the working gap can handle high solids consistency for effective cleaning, while the discharge side maintains lower consistency for easy conveyance. The water injection point and outlet positioning create this segmentation, allowing each zone to operate at its optimal consistency level independently.
3Ease of operation
If atmospheric operation with pump sump is used, then handling of floating plastic is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent replaces the atmospheric pump sump system with a hydraulic suction system using water injection. This eliminates the need for a large pump sump and atmospheric pressure operation while still effectively handling floating plastic materials. The water jet creates the necessary suction to draw materials of varying densities through the refiner without relying on atmospheric pressure or large containment structures.
Solution Approach 2:
The patent extracts and eliminates the pump sump component from the system by using direct water injection to create suction in the working gap. This removes the complex atmospheric operation infrastructure while maintaining the ability to handle floating materials, simplifying the overall device structure and reducing space requirements.
4Ease of operation
If large amount of water is used to maintain low consistency, then pumpability is improved, but energy consumption increases due to high water acceleration
Solution Approach 1:
The hydraulic suction system uses water injection to create negative pressure that draws material through the refiner, eliminating the need for large volumes of water to be accelerated for pumpability. The water is injected tangentially at controlled rates just sufficient to create the suction effect, rather than using excessive water to maintain low consistency throughout the system, significantly reducing the energy required for water acceleration.
Solution Approach 2:
The patent changes the consistency parameter dynamically - maintaining high solids consistency in the working gap where it improves cleaning efficiency, and only using sufficient water to create the suction effect and enable discharge. This avoids the energy waste of using large water volumes to maintain low consistency throughout the entire system, reducing energy consumption while preserving pumpability where needed.
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 enables efficient and energy-effective cleaning of plastic snippets by maintaining high cleaning consistency and low discharge consistency, reducing energy consumption and improving the conveyance of plastic and impurities, while avoiding the need for a pump sump and enhancing the compactness and mobility of the system.
Implementation Method 1
a water pump (32) is connected to the outlet pipe (20) for pumping water through the outlet pipe (20), wherein the water pumped through the outlet pipe (20) by the water pump (32) is designed as a water jet that flows laterally past the working gap and is tangential to the working gap and generates a negative pressure that exerts a suction effect on the working gap
Implementation Method 2
plastic chips, so-called flakes, for example, are cleaned of cellulose and other adhering substances with the addition of water, in particular by friction between the refiner discs facing one another
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device for cleaning plastic in the course of plastic recycling, comprising a refiner (10) having two refiner tools facing each other, of which at least one is rotationally driven and which bound a working gap between each other, wherein the refiner has an inlet that opens into the working gap, and comprising an input apparatus connected to the inlet for inputting the plastic to be cleaned into the inlet, wherein the refiner has an outlet, which is likewise connected to the working gap and through which the plastic is led away to an exit, wherein the outlet comprises an outlet pipe (20), which is connected to the working gap and leads to the exit, wherein the outlet pipe is connected to a water pump (32), wherein the water pumped through the outlet pipe by means of the water pump has a suction effect on the working gap during operation, in such a way that cleaned plastic is conveyed from the working gap into the outlet pipe. The invention further relates to a corresponding method.