Blood Pump Impeller Axial Gap Control
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Solution Overview
Problem
Implantable blood pumps face challenges in effectively washing the impeller surfaces due to potential thrombus stagnation near ceramic disks, which can lead to blood flow issues.
Innovation Solution
A method and system involving a controller that applies specific voltage waveforms to stators to rotate the impeller, temporarily increasing the axial gap between the impeller and stators, allowing for improved washing of the impeller surfaces by momentarily moving the impeller axially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impeller operates close to the stators for efficient pumping, then pumping efficiency is improved, but thrombus stagnation occurs on the impeller surfaces
Solution Approach 1:
The patent applies periodic asymmetric voltage waveforms to the stator coils that create oscillating axial forces on the impeller. These periodic forces cause the impeller to oscillate axially between the stators, periodically increasing the axial gap to prevent thrombus stagnation while maintaining efficient pumping during the majority of the cycle. The periodic action allows the system to alternate between high-efficiency operation and thrombus-prevention modes.
Solution Approach 2:
The patent changes the electrical parameters (voltage waveform asymmetry and phase shifting) of the stator coils to generate variable axial forces on the impeller. By modifying the voltage waveform characteristics rather than the mechanical structure, the system dynamically adjusts the axial gap between the impeller and stators, optimizing both pumping efficiency and thrombus prevention without requiring mechanical modifications.
2Reliability
If asymmetric voltage waveforms are applied to rotate the impeller axially, then impeller washing is improved, but control complexity increases
Solution Approach 1:
The patent replaces complex mechanical adjustment mechanisms with electrical control. Instead of using mechanical systems to physically adjust the impeller position or create washing motions, the invention uses asymmetric voltage waveforms applied to electromagnetic stator coils to generate the necessary axial forces. This substitution of electrical control for mechanical complexity simplifies the overall system while achieving the desired impeller washing effect.
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 effectively increases the washing of impeller surfaces, reducing thrombus stagnation and enhancing blood flow by creating a larger axial gap for larger thrombus particles to pass through, thereby improving the operation of implantable blood pumps.
Implementation Method 1
applying a first voltage waveform at first phase to the first stator to generate a magnetic field to rotate the impeller
Implementation Method 2
generate a magnetic field to rotate the impeller
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method of operating an implantable blood pump having a first stator, a second stator, and an impeller movably disposed there between. The method includes applying a first voltage waveform at first phase to the first stator to generate a magnetic field to rotate the impeller. A second voltage waveform is applied at a second phase shifted from the first phase to the second stator to rotate the impeller, the second voltage waveform is asymmetric to the first voltage waveform.