Hydroelectric Intake Gate Self-Cleaning Strip Mechanism
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Solution Overview
Problem
The existing intake rakes in hydroelectric power stations face significant flow impediment due to the deposition of bed load and sediment, which is difficult to clear effectively as the required flow velocity is not consistently achieved across the intake screen.
Innovation Solution
A horizontal intake rake with a cleaning strip featuring rear and front comb strips, oriented at an angle to the lattice bars, which effectively removes bed load and flotsam by moving with the flow and sliding debris back, supported by the water flow, reducing the force required for cleaning and ensuring self-cleaning functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a horizontal intake rake is used to prevent flow impediment, then flow efficiency is maintained, but bed load and sediment still deposit on the screen requiring cleaning
Solution Approach 1:
The cleaning strip is designed to be moved by the water flow itself rather than requiring an external drive mechanism. The flow moves the cleaning strip in the downstream direction to push debris, and the strip naturally returns upstream when flow decreases, creating a self-sustaining cleaning cycle that maintains flow efficiency without additional mechanical complexity
Solution Approach 2:
The cleaning strip changes its functional state based on flow conditions: during high flow it moves downstream to push debris, during low flow it returns upstream to scrape deposits, and during very low flow the spring mechanism provides the returning force. This parameter-based state change allows the system to adapt to varying flow conditions and maintain cleaning effectiveness
2Reliability
If a rake cleaner is used to strip flotsam from vertical lattice bars, then cleaning effectiveness is improved, but the device complexity increases with drive mechanisms
Solution Approach 1:
The cleaning strip eliminates the need for complex drive mechanisms by using the water flow itself to move the strip downstream during cleaning operations. The return movement upstream is achieved through a simple spring mechanism rather than a motorized system, significantly reducing device complexity while maintaining reliable cleaning effectiveness
Solution Approach 2:
The invention extracts the drive mechanism from the cleaning system and replaces it with a passive flow-driven approach. The cleaning strip is moved only by water flow and spring force, removing the need for motors, controllers, and complex mechanical drives while achieving effective cleaning through the comb strips
3Productivity
If flushing is used to clear the intake rake, then some debris is removed, but the required flow velocity is not achieved at all points
Solution Approach 1:
The cleaning function is segmented into two distinct phases: downstream movement where the cleaning strip pushes debris during high flow, and upstream return movement where the strip scrapes deposits during low flow. This segmentation ensures that cleaning occurs at all points of the intake rake regardless of flow velocity variations, overcoming the limitation of uniform flushing
Solution Approach 2:
The cleaning strip is designed to dynamically adapt to flow conditions by moving downstream with the flow to push debris and returning upstream when flow decreases to scrape deposits. This dynamic behavior ensures comprehensive cleaning at all locations on the intake rake, addressing the flow velocity distribution problem
4Reliability
If the cleaning strip is moved against the flow upstream, then debris can be scraped off, but lifting forces act on the cleaning strip
Solution Approach 1:
The cleaning strip is given a streamlined, curved cross-section that reduces water resistance and lifting forces during upstream movement. The curved shape allows water to flow smoothly over the strip rather than creating lift, reducing the forces that try to lift the strip from the intake rake while maintaining effective debris scraping
Solution Approach 2:
The cleaning strip changes its interaction with water based on movement direction: during downstream movement it pushes debris with flow support, during upstream movement the streamlined shape reduces lifting forces, and during very low flow the spring mechanism provides the returning force. This parameter-based adaptation minimizes unwanted lifting forces while maintaining cleaning effectiveness
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 ensures reliable removal of debris and flotsam from the intake rake, reducing deposition and maintaining flow efficiency, even during flooding, and is particularly advantageous for underwater installations with an inclination that aids in pushing down deposited debris.
Implementation Method 1
The streamlined design of the cleaning strip also has the effect that the forces that try to lift the cleaning strip from the inlet rake are reduced
Implementation Method 2
If the cleaning bar is moved with the flow over the inlet rake, bed material and flotsam are largely moved along with the cleaning bar
Implementation Method 3
an incline that falls downwards with the direction of flow advantageously supports the pushing down of the deposited debris from the inlet rake
Data Source
AI summary
The invention relates to an intake gate of a hydroelectric power plant, comprising bars (8) which are horizontal to the direction of the flow of water or are arranged at a slight angle to the horizontal. According to the invention, said intake gate comprising a cleaning strip (6) which is arranged transverse to the bars (8) and can be moved in the longitudinal direction on the bars (8). At least one combing bar (17, 19) engages by means of its teeth (18) in the intermediate area (13) of the bars (8) and the cleaning strip (6) is designed, on the side facing the flow, to deviate the flow, and comprises in particular bevels and/or rounded sections (20).