Rotary Blood Pump Magnetic Hydrodynamic Suspension
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Solution Overview
Problem
Current rotary blood pumps, particularly centrifugal ones, face challenges with mechanical bearings causing thrombosis and hemolysis, and traditional seals leading to premature wear, necessitating the development of sealless pumps with hydrodynamic and magnetic bearings for improved blood flow and reduced risk of complications.
Innovation Solution
A centrifugal rotary blood pump design featuring a magnetically and hydrodynamically suspended impeller within a cylindrical pumping chamber, utilizing passive and active magnetic flux and hydrodynamic thrust bearings to maintain radial and axial stability without mechanical contact, ensuring efficient blood flow and minimizing thrombosis and hemolysis risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical bearings are used to stabilize the rotor, then the impeller can remain free to rotate smoothly, but mechanical bearings within the volume of blood become a source of thrombosis and premature wear
Solution Approach 1:
The patent replaces mechanical contact bearings with magnetic bearings that use magnetic fields to suspend and stabilize the impeller. This eliminates mechanical contact between moving parts, removing the source of thrombosis and wear while maintaining smooth rotation through magnetic suspension forces.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the impeller and the pump housing. These magnetic fields provide stabilization and suspension without requiring direct mechanical contact, thus preventing thrombosis while enabling controlled rotation.
2Ease of operation
If mechanical bearings are used to stabilize the rotor, then the impeller can remain free to rotate smoothly, but the mechanical bearings necessitate protrusion of the shaft beyond the pumping chamber requiring seals
Solution Approach 1:
The patent replaces the mechanical shaft and bearing system with a magnetic coupling system where the impeller is suspended by magnetic fields. This eliminates the need for a protruding shaft and associated seals, simplifying the device while maintaining free rotation capability.
Solution Approach 2:
The patent extracts the impeller from the traditional shaft-connected configuration and suspends it freely within the pumping chamber using magnetic fields. This removes the shaft and seal components entirely, eliminating the complexity associated with mechanical protrusions through the chamber wall.
3Reliability
If seals are used for mechanical shafts, then blood can be contained within the pumping chamber, but seals cause thrombosis of the blood and wear out prematurely
Solution Approach 1:
The patent replaces mechanical seals with magnetic fields that contain and control the impeller position without physical contact. This maintains blood containment within the chamber while eliminating the thrombogenic surface of mechanical seals.
Solution Approach 2:
The patent uses magnetic fields as an intermediary to achieve both blood containment and impeller control without mechanical seals. The magnetic field acts as a non-contact barrier that prevents blood leakage while avoiding thrombosis associated with mechanical seal surfaces.
4Object-affected harmful factors
If passive magnetic bearings are used to suspend the impeller, then radial suspension is achieved, but passive magnetic bearings alone cannot keep the impeller suspended in both axial and radial directions
Solution Approach 1:
The patent merges passive magnetic bearings for radial suspension with active magnetic bearings for axial suspension. This combination provides complete three-dimensional impeller stabilization, achieving both radial and axial control while maintaining a relatively simple overall system architecture.
Solution Approach 2:
The patent employs a magnetic bearing system that performs multiple functions: passive magnetic bearings provide radial suspension, while active magnetic bearings provide axial suspension and positioning. This multi-functional magnetic bearing arrangement eliminates the need for separate mechanical suspension systems for different directions.
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 enhances the physical size, performance, and efficiency of rotary blood pumps, providing consistent and reliable therapeutic support by maintaining blood flow without mechanical contact, reducing the risks of thrombosis and hemolysis, and ensuring dynamic suspension of the impeller for improved fluid dynamics.
Implementation Method 1
The impeller is radially and axially suspended in rotation by magnetic forces created by passive and active sources of magnetic flux acting upon the impeller
Implementation Method 2
hydrodynamic thrust bearings provided on an upper surface of the impeller
Implementation Method 3
a centrifugal rotary blood pump design featuring a magnetically and hydrodynamically suspended impeller within a cylindrical pumping chamber
Data Source
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AI summary
A rotary blood pump (10) comprising a housing defining a pumping chamber (3) with upper and lower interior surfaces and having a blood inlet (7) and a tangential blood outlet (13), and a rotatable impeller (22) within the pumping chamber (3) and adapted to increase blood pressure within the pumping chamber (3) to cause blood to move to the blood outlet (13), the impeller (22) having at least one raised surface area adjacent the upper interior surface of the pumping chamber (3). The rotary blood pump further comprises a first tapered region (34) of the raised surface area having a leading portion (36) and a trailing portion (37) and a gap between the first tapered region (34) and the upper interior surface of the housing decreases from the leading portion (36) to the trailing portion (37) creating a hydrodynamic thrust load acting to bias the impeller (22) axially away from the upper interior surface of the housing when the impeller (22) is rotating, each of the first tapered regions having a shroud (43, 44) extending from the leading portion to the trailing portion along each of its inner (43) and outer (44) boundaries.