Open Impeller Pump Blade Wall for Low-Shear Fish Passage
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Solution Overview
Problem
Centrifugal pumps pose a risk to aquatic life, such as fish, due to high shear forces that can cause scraping collisions with the pump housing or wear ring, and existing designs do not adequately address this issue while maintaining high flow rates and cost-effectiveness.
Innovation Solution
The centrifugal pump design incorporates a wall along the outer edge of the blade, forming a sliding channel to reduce shear forces, which can be implemented using forming or additive manufacturing processes, and includes a guide device to facilitate the transport of living organisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blade outer edge is designed to be flush with the housing to maintain high flow rate, then productivity is improved, but shear forces increase causing harm to aquatic life
Solution Approach 1:
The patent applies local quality by adding a wall structure specifically at the outer edge region of the blade, while keeping the rest of the blade design unchanged. This localized modification creates a protective feature that reduces shear forces on aquatic life without compromising the overall flow rate and pumping performance of the impeller
2Object-affected harmful factors
If a wall is added along the outer edge of the blade to reduce shear forces, then object-affected harmful factors are reduced, but device complexity increases
Solution Approach 1:
The blade is segmented into distinct functional zones: the main blade body for fluid transport and a separate wall structure at the outer edge for fish protection. This segmentation allows each part to perform its specific function independently, simplifying the overall design approach while achieving multiple objectives
3Object-affected harmful factors
If the blade wall is designed as a projection to reduce shear forces, then object-affected harmful factors are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by optimizing the wall height, thickness, and positioning along the blade outer edge to achieve effective fish protection while maintaining manufacturability. The wall dimensions are carefully selected to provide protection without requiring excessive manufacturing precision
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 significantly reduces shear forces on fish and other organisms, ensuring their safe passage through the pump while maintaining high flow rates and allowing for easy assembly and replacement of spare parts.
Implementation Method 1
the blade has a wall along a defined area of the outer edge to reduce shear forces
Implementation Method 2
the centrifugal forces of the pump press fish against the wear ring and/or the pump housing
Data Source
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AI summary
The invention relates to a centrifugal pump assembly (1) comprising a housing (2), an inlet opening (3), an outlet opening (4), and an open impeller (5) with a hub (7) supporting at least one blade (8). The blade (8) has a leading edge (15), an exit edge (16), a suction-side surface (17), a pressure-side surface (18), and an outer edge (11) extending along an inner wall (10) of the housing (2). The blade (8) has a wall (13) along a defined region (14) of the outer edge (11) to reduce shear forces.