Blood Pump Bearing Geometry for Washed Flow Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Blood pumps face challenges with blood clots and hemolysis due to stagnation in bearing areas, which existing designs fail to adequately address, particularly with sleeve and cone bearings that do not effectively enhance fluid flow and lubrication to prevent thrombosis and hemolysis.
Innovation Solution
A modular bearing system incorporating uniquely designed sleeve and cone bearings with modified geometries to promote full washing of bearing surfaces, including features like thrust rings and segmented cone bearings with channels to enhance blood flow and reduce stagnation, combined with a blood flow assist system that includes an impeller assembly and drive unit with curved bearing surfaces to facilitate efficient blood circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sleeve or cone bearings are used in blood pumps, then radial and axial confinement of the impeller is achieved, but blood stagnation occurs in bearing areas leading to thrombosis and hemolysis
Solution Approach 1:
The bearing surface is segmented into multiple zones with different geometries (e.g., tapered sections, straight sections, recessed areas) to create varied flow patterns that prevent stagnation while maintaining bearing functionality
Solution Approach 2:
Different regions of the bearing surface are designed with specific geometries optimized for their local function: some areas promote blood flow through, others provide lubrication, and others ensure radial/axial confinement, creating locally optimized conditions that collectively prevent thrombosis
2Object-generated harmful factors
If bearing geometries are modified to enhance blood flow through bearing regions, then thrombosis risk is reduced, but bearing performance and impeller confinement may be compromised
Solution Approach 1:
The bearing design incorporates dynamic flow characteristics where blood flow patterns change along the bearing surface, with some regions designed to channel flow through and others to allow flow parallel to the surface, creating a dynamic system that adapts to operational conditions while maintaining both safety and performance
Solution Approach 2:
The bearing design utilizes multiple spatial dimensions and orientations (radial, axial, and circumferential flow components) to create complex three-dimensional flow patterns that simultaneously achieve blood safety and bearing functionality, rather than relying on single-direction flow
3Reliability
If conventional bearing designs are used, then impeller constraint is maintained, but fluid flow enhancement and lubrication are insufficient
Solution Approach 1:
The bearing design incorporates hydraulic principles by utilizing blood flow itself as the lubricating medium, with bearing geometries optimized to generate hydrodynamic lubrication effects that enhance both fluid flow efficiency and impeller constraint without requiring additional lubrication systems
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 solution minimizes thrombosis and hemolysis by ensuring thorough washing of bearing surfaces and efficient blood flow, reducing the risk of clot formation and improving the overall performance of blood pumps.
Implementation Method 1
The convex bearing surface includes a plurality of distally-projecting segments, the plurality of distally-projecting segments spaced apart circumferentially to define at least one channel between adjacent segments
Implementation Method 2
a drive bearing between the drive magnet and the impeller assembly, the drive bearing comprising a second curved bearing surface (e.g., a convex bearing surface) shaped to mate with (e.g., fit within) the first curved bearing surface
Data Source
AI summary
A blood flow assist system can include an impeller assembly including an impeller shaft and an impeller on the impeller shaft, a primary flow pathway disposed along an exterior surface of the impeller. The system can include a rotor assembly at a proximal portion of the impeller shaft. A secondary flow pathway can be disposed along a lumen of the impeller shaft. During operation of the blood flow assist system, blood can be pumped proximally along the primary flow pathway and the secondary flow pathway. The system can include a sleeve bearing distal the impeller. The system can include a drive unit having a distal end disposed distal a proximal end of the second impeller. The drive unit comprising a drive magnet and a drive bearing between the drive magnet and the impeller assembly.