Rotary Rake Screen for Continuous Debris Removal
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Solution Overview
Problem
Existing water systems with overflow sills face challenges in efficiently removing contaminants during prolonged overflow situations, as previous solutions like screw conveyors are complex to manufacture and maintain, and can become clogged, while also requiring intricate sealing and contaminant removal processes.
Innovation Solution
A sieve rake arrangement with a driven rotary rake that sweeps the underside of a retaining sieve to clear accumulated contaminants, featuring a U-shaped bristle carrier or scraper strips, and a modular design for easy retrofitting and adaptation to different systems, ensuring continuous contaminant removal without clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw conveyor is used to remove contaminants, then continuous contaminant removal is achieved, but the device becomes complex to manufacture and maintain with intricate sealing requirements
Solution Approach 1:
The screen arrangement is divided into modular components: a retention screen with upstream and downstream sides, a rotary rake with multiple rake arms, and a drive mechanism. This segmentation allows for easier manufacturing, maintenance, and adaptation to different water system configurations while maintaining continuous contaminant removal functionality.
Solution Approach 2:
Instead of using a screw conveyor that requires complex sealing to prevent water ingress to the drive mechanism, the invention positions the rotary rake to rotate in the water-filled storage chamber and uses simple overhead sealing at the screen surface. The drive mechanism is positioned above the water level, eliminating the need for complex underwater seals while still achieving continuous contaminant removal.
2Object-affected harmful factors
If a retention screen is used during prolonged overflow, then contaminants are retained, but the screen becomes clogged and flow capacity decreases
Solution Approach 1:
The rotary rake operates continuously to remove contaminants from the retention screen surface, ensuring that the screening function is maintained without interruption. The rake arms constantly sweep the screen surface, preventing clog formation and maintaining flow capacity throughout prolonged overflow events, while still effectively retaining contaminants.
Solution Approach 2:
The rotary rake is driven by a motor positioned above the water level, and the entire cleaning mechanism serves itself by automatically removing accumulated contaminants from the screen. The system requires minimal external intervention, with the rake continuously self-cleaning the retention screen to maintain optimal flow capacity.
3Stress or pressure
If a height-adjustable weir plate is used to maintain target storage level, then overflow control is improved, but the cleaning mechanism becomes dependent on water level drops which limits effectiveness during prolonged overflow
Solution Approach 1:
The rotary rake serves multiple functions: it cleans the retention screen during normal operation, maintains screen capacity during prolonged overflow, and can be driven by the weir plate movement itself when water levels drop. This multi-functionality ensures effective cleaning regardless of the operational phase or duration of overflow events.
Solution Approach 2:
The cleaning mechanism is designed to be dynamic, adapting its operation to different water level conditions. The rotary rake can be driven continuously by a motor or passively driven by the movement of the weir plate itself, allowing the system to adjust its cleaning action based on whether the water level is stable or dropping, ensuring effective cleaning in all operational scenarios.
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 maintains flow by continuously removing contaminants, is easy to install and configure, and keeps the drive motor dry, avoiding complex sealing measures, thus addressing the inefficiencies of previous technologies.
Implementation Method 1
The rotary rake provided on the underside of the retention screen sweeps across the screen and removes accumulated debris
Implementation Method 2
the rotary rake can include at least one brush arm which can be driven rotaryally around the said upright rake axis or possibly also back and forth in order to brush over the underside of the sieve
Implementation Method 3
The aforementioned rotary rake may include one or more squeegee-like clearing bars that sweep across the retention screen and remove contaminants from it
Data Source
Figure 1~3
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Figure 7~8
AI summary
The present invention relates to a water system, in particular a combined sewer overflow and/or rainwater treatment system, with a storage space 21 with an overflow threshold 11, and a screen arrangement 1 for retaining contaminants when overflowing, wherein the screen arrangement comprises a retention screen 3 arranged upstream of the overflow threshold in the storage space and a rotary rake 24 driven by rotation about an upright rake axis 23 for clearing the underside of the retention screen.