Intake Rake Beading for Hydro-Electric Flow Loss Reduction

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Solution Overview

Problem

Existing intake rakes for hydroelectric power plants cause significant flow losses and are inefficient in preventing fish from entering turbines, leading to financial losses and environmental concerns, while also being prone to clogging and material degradation.

Innovation Solution

The intake rake features slide bars with a beading in the form of an eyelet or loop, reducing the risk of fish injury and maintaining low obstruction, made of stainless steel with a thin material thickness and a bevelled contour to minimize flow resistance and facilitate easy maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If thick slide bars with large spacing are used to prevent fish injury, then fish protection is improved, but the degree of obstruction increases significantly

Engineering Contradiction:

Improvefish injuryVSAvoidflow losses

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The slide bars have non-uniform cross-sections with thickenings at specific locations (leading edges and intermediate positions) rather than being uniformly thick. This local thickening provides fish protection where needed while maintaining thin sections elsewhere to minimize obstruction degree and flow losses.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The slide bars are divided into multiple sections with different thickness characteristics - leading edges have thickenings for fish protection, intermediate sections have additional thickenings, and trailing sections are thinner. This segmentation allows optimization of different regions for different functions.

Inventive Principle:

Principle #1Segmentation

2Reliability

If slide bars with cavities are used to detect wear, then reliability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvewear detection capabilityVSAvoidmanufacturing difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The thickenings are pre-formed as integral parts of the slide bar structure during manufacturing, creating built-in wear indicators without requiring separate cavity formation steps. This preliminary incorporation of wear detection features simplifies manufacturing while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

3Loss of energy

If sharp-edged inlet rakes are used to reduce obstruction, then flow losses are reduced, but fish injury increases

Engineering Contradiction:

Improveflow lossesVSAvoidfish injury

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The slide bars have locally thickened sections at the leading edges and intermediate positions, providing rounded protective surfaces where fish contact is most likely, while maintaining thinner sections elsewhere to minimize overall obstruction and flow losses.

Inventive Principle:

Principle #3Local quality

4Loss of energy

If closely spaced thin slide bars are used to reduce obstruction, then degree of obstruction is reduced, but fish protection effectiveness decreases

Engineering Contradiction:

Improveflow lossesVSAvoidfish protection

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The slide bars feature segmented thickness distribution with multiple thickenings at specific locations along their length, allowing closely spaced thin bars to provide enhanced fish protection at critical locations while maintaining low overall obstruction degree.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2166158B1Intake screen for water removal structures, for example hydro-electric plants

Publication Date: 2013.01.16 UNIVERSITY OF KASSEL

Figure 1~2
Figure 3

AI summary

The intake rake (1) is arranged in front of an intake of a turbine, and has multiple rake bars (2), which are arranged one after another. The rake bars have a flanged over portion in form of a strap. A light distance between the computing distances is provided between 10 millimeter and 20 millimeter within the range of the flanged over portion.