Fish Friendly Pump with Curved Guiding Blades
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Solution Overview
Problem
Axial flow pumps, commonly used in polder pumping stations, pose a risk to fish due to their design, and existing modifications to make them 'fish-friendly' often compromise efficiency.
Innovation Solution
A pump design featuring a rotor with slanting guiding blades and a cylindrical stator, optimized to maintain high efficiency while preventing fish entrapment, includes a conical hub, tapered stator, and strategically placed blades to ensure fish passage, with specific angles and edge profiles to enhance hydraulic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional axial flow pumps are used for efficient water pumping, then pump efficiency is maintained, but fish survival rate deteriorates due to entrapment and injury
Solution Approach 1:
The rotor blades are designed with specific curvature characteristics, including a rounded leading edge and a curved suction side, which smooths the flow path and reduces turbulence. The stator blades also feature curved surfaces that guide flow smoothly. This curvature design prevents fish from being trapped in sharp edges and turbulence zones while maintaining hydraulic efficiency.
Solution Approach 2:
The patent applies specific parameter ranges to blade geometry: rotor blade inlet angle between 15-45 degrees, rotor blade outlet angle between 120-160 degrees, and stator blade inlet angle between 10-30 degrees. These optimized parameters create a flow environment that reduces fish entrapment while preserving pump performance.
2Productivity
If the number of rotor blades is increased to improve pump performance, then hydraulic efficiency improves, but fish passage capability deteriorates due to reduced clearance and increased entrapment risk
Solution Approach 1:
The patent employs a reduced number of rotor blades (1-3 blades, preferably 2) compared to conventional designs that typically use 4 or more. This partial action approach provides sufficient hydraulic efficiency for polder pumping while creating larger clearances between blades that allow fish to pass safely without entrapment.
3Ease of manufacture
If cylindrical stator is used with conventional design, then manufacturing is simplified, but fish safety deteriorates due to narrowing clearance at stator inlet
Solution Approach 1:
The stator inlet is designed with a curved, rounded leading edge instead of a sharp cylindrical transition. This curvature creates a smooth flow path that prevents fish from being trapped in the narrowing clearance zone, while the overall cylindrical form of the stator body remains simple to manufacture.
4Productivity
If rotor blades have sharp edges for hydraulic optimization, then pump efficiency improves, but fish safety deteriorates due to increased injury risk
Solution Approach 1:
The rotor blades feature a rounded leading edge and curved suction side that eliminate sharp edges. This curvature design maintains efficient hydraulic flow while significantly reducing the risk of fish injury from contact with blade edges.
Solution Approach 2:
The patent specifies that the rotor blade leading edge radius should be at least 5% of the rotor hub diameter, and the suction side should have a specific curvature radius. These parameter changes ensure smooth flow paths that protect fish while maintaining pump efficiency.
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 design achieves survival rates exceeding 97% for fish while maintaining efficiency comparable to standard polder pumps, ensuring both fish safety and operational performance.
Implementation Method 1
a drivable screw shape rotor or impeller (5), which can be driven to rotate about a rotational axis (X)
Implementation Method 2
a stator (8), which is connected to the inner wall of the tubular housing (2) by means of radial guiding blades (9)
Data Source
Figure 1
Figure 2~3
AI summary
Pump or turbine apparatus (1) comprising a tubular housing (2) with an inlet opening (3) and an outlet opening (4), and a drivable screw-shaped rotor (5) with a hub (6) carrying at least one blade (7). The rotor is in line with a stator (8) which is connected to the inner wall of the tubular housing (2) by means of guiding blades (9). The guiding blades comprise a slanting end (10) directed to the inlet opening and making an entrance angle Y with the rotational axis X, and a second end (11) directed to the outlet opening (4) which is parallel to the rotational axis. The slanting end (10) of the guiding blades (9) slants under an angle with the rotational axis which is smaller than 45°.