Inner Magnet Coupling in Rotodynamic Pump Impeller
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Solution Overview
Problem
Existing inner drive permanent magnet coupled rotodynamic pumps are large, heavy, and prone to impeller thrust imbalance, with ineffective cooling and complex internal recirculation paths that can lead to stagnation and solids accumulation.
Innovation Solution
A rotodynamic pump design with a radial, inner drive permanent magnet coupling positioned inside the impeller, featuring a simplified internal circulation cooling flow path and a large central opening for the magnet coupling, which reduces stagnation, balances thrust loads, and enhances cooling by exposing the canister to incoming fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the magnet coupling is positioned outside the impeller (conventional design), then the pump structure is simpler to manufacture, but the pump becomes larger, heavier, and experiences impeller thrust imbalance
Solution Approach 1:
The magnet coupling is positioned inside the impeller hub, nesting the drive mechanism within the pumping component. This eliminates the need for separate magnet coupling housings and reduces the overall pump footprint, directly addressing the weight and size issues while maintaining manufacturing simplicity through integrated design
2Ease of manufacture
If the magnet coupling is positioned outside the impeller (conventional design), then the manufacturing is easier, but the pump experiences forward thrust load imbalance
Solution Approach 1:
The impeller hub is designed with asymmetric internal chambers and bearing arrangements that specifically counterbalance the thrust forces generated by the magnet coupling. This asymmetric internal structure compensates for the off-center magnetic forces, eliminating thrust imbalance while keeping the overall design manufacturable
3Temperature
If complex internal recirculation paths are used for cooling, then cooling effectiveness is improved, but fluid stagnation and solids accumulation occur
Solution Approach 1:
The cooling system is segmented into multiple independent channels with different flow paths. This segmentation allows the cooling fluid to reach all critical areas (magnet coupling, canister, bearings) through separate routes, ensuring effective cooling while maintaining continuous flow without stagnation in any single path
4Device complexity
If the canister is not exposed to incoming fluid, then the sealing is simpler, but cooling effectiveness is reduced
Solution Approach 1:
The canister serves multiple functions: it acts as a seal between the magnet coupling and impeller, provides structural support, and simultaneously serves as a heat sink exposed to the incoming cooling fluid. This multi-functionality achieves effective cooling without complicating the sealing structure
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 results in a more compact, balanced, and easily maintainable pump with reduced forward thrust load, effective cooling, and minimized stagnation, suitable for applications requiring hygiene and efficient flushing.
Implementation Method 1
The radial magnetic couplings consist of three main components: a larger, outer coupling component (aka an outer magnet or outer rotor) with multiple permanent magnets on its inner surface; a smaller, inner coupling component (aka an inner magnet or inner rotor) with multiple permanent magnets on its outer surface; and a containment canister (aka a can, shell, shroud, or barrier) separating the inner and outer components and forming a boundary for the fluid chamber. The magnets on the inner and outer components are disposed in alignment with each other to match up and synchronize the inner and outer components, such that as one component is rotated, the other component is synchronized and forced to follow
Implementation Method 2
Rotodynamic pumps have been developed with a magnet coupling that utilizes an impeller that is driven via a non-contacting permanent magnet coupling in a radial magnet orientation
Data Source
AI summary
Rotodynamic pumps having an inner drive permanent magnet coupling disposed inside an impeller are provided. The impeller has a casing having a pumping region generally in a pumping plane that is perpendicular to the rotational axis of the impeller and aligned with a permanent magnet coupling that includes outer magnets that are connected to the impeller and at least partially aligned with the pumping region of the impeller, and inner magnets that are connected to an inner magnet ring and are axially aligned with the outer magnets. A canister is sealed to the casing and separates the outer magnets from the inner magnets.