Segmented Overflow Canals Reduce Air Entrainment in Dredger Hoppers
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Solution Overview
Problem
Trailing suction hopper dredgers face environmental issues due to the formation of plumes caused by air mixing with overflow water, which reduces the specific weight of the mixture and leads to sticking on the ship's hull, propeller interference, and reduced transport capacity, causing environmental damage.
Innovation Solution
An overflow system with a series of canals surrounding the overflow tube, allowing for controlled flow and air escape, adapting to varying fluid levels with different inlet heights and sizes, and connecting to the overflow tube to minimize turbidity and plume formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If overflow water is released vertically from the hopper, then the overflow system is simple in structure, but air mixes with the overflow reducing specific weight and causing plume formation that damages the environment
Solution Approach 1:
The overflow system is segmented into multiple canals (first canal, second canal, third canal) arranged at different heights around the hopper. Each canal handles overflow at specific water levels, dividing the single vertical overflow into multiple controlled flow paths that reduce air mixing and plume formation while maintaining structural simplicity
Solution Approach 2:
The invention transitions from a single vertical overflow dimension to a multi-dimensional arrangement with canals positioned at different heights and angles around the hopper. This spatial distribution allows overflow to occur through multiple pathways simultaneously, reducing the vertical velocity and air mixing that causes plumes
2Productivity
If a single vertical overflow is used, then the system has high transport capacity, but air resistance reduces the effective capacity and causes sticking on the ship's hull
Solution Approach 1:
The single vertical overflow is segmented into multiple canals positioned at different heights. This segmentation distributes the overflow flow across multiple pathways, reducing the velocity and air mixing in each individual canal, thereby minimizing air resistance and improving effective transport capacity
Solution Approach 2:
The system dynamically adapts to varying water levels in the hopper by activating different combinations of canals. As water levels rise or fall, different canals become active or inactive, optimizing the overflow capacity to match the actual water volume and maintain efficient transport while minimizing air resistance
3Productivity
If overflow capacity is increased to handle variations in fluid levels, then the system can handle higher flow rates, but more air mixes in reducing the specific weight and increasing plume formation
Solution Approach 1:
Multiple canals are positioned at different heights around the hopper, with each canal capable of handling overflow at specific water levels. This segmentation allows the system to handle variations in fluid levels by activating only the necessary canals, increasing overflow capacity while maintaining controlled flow that minimizes air mixing and plume formation
Solution Approach 2:
The overflow system dynamically adjusts its capacity by activating different combinations of canals based on water levels. When water levels are high, more canals are activated to increase capacity; when levels are low, fewer canals are used. This dynamic adjustment maintains optimal flow conditions that reduce air mixing and plume formation while handling varying flow rates
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 system effectively reduces or eliminates air in the overflow, minimizing turbidity and plume formation, thereby preventing environmental damage and optimizing transport capacity by maintaining a controlled flow.
Implementation Method 1
The overflow tube comprises an opening able to take in head water from the hopper and release air from the overflow system
Implementation Method 2
Water from the hopper flows into the overflow through an entry disk or directly into the overflow from the top
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
An overflow system (20) for a hopper dredger (10) includes an overflow tube (22); and a plurality of canals (26a-26e) adjacent and substantially parallel to the overflow tube (22). The plurality of canals (26a-26e) have inlets (28a-28e) at different heights for taking in head water from the hopper (18). The plurality of canals (26a-26e) fluidly connect to the overflow tube (22) at a point downstream from the inlets (28a-28e).