Rotating Valve Piston Pump for Variable Stroke Volume
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current positive displacement pumps used in ventricular assist devices are insensitive to natural circulatory feedback mechanisms, leading to issues such as over-pumping, arrhythmias, hemolysis, and right heart failure, and are limited in their ability to vary stroke volume and respond to changes in preload and afterload.
Innovation Solution
The design incorporates a pumping chamber forming a loop with a drive piston and a valve piston, where the drive piston's actuation creates a shunt allowing fluid energy to carry extra volume, making the system sensitive to preload and afterload, and a control system adjusts the pump's operation based on sensed physiological parameters to mimic the heart's natural response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional centrifugal or axial flow pumps are used to pump blood, then high-speed fluid circulation is achieved, but hemolysis occurs due to excessive shearing strains
Solution Approach 1:
The patent replaces the traditional mechanical impeller-based centrifugal or axial flow pumping mechanism with a magnetic field-based actuation system. Electromagnets and permanent magnets generate magnetic forces to move the drive piston, eliminating high-speed mechanical rotation and associated shearing strains that cause hemolysis, while still achieving effective blood circulation through controlled positive displacement
Solution Approach 2:
The patent employs a magnetic fluid coupling system where the magnetic drive mechanism transfers rotational motion to the pistons through magnetic fields rather than direct mechanical contact. This hydraulic-like magnetic coupling eliminates the need for high-speed rotating impellers that create damaging shear forces, while maintaining efficient power transmission to achieve the required circulation rates
2Reliability
If positive displacement pumps with fixed stroke volume are used, then reliable fluid displacement is achieved, but the system cannot respond to changes in preload and afterload
Solution Approach 1:
The patent implements a dynamic control system where the stroke volume of the drive piston can be varied in real-time based on physiological feedback. The electromagnetic actuation system allows continuous adjustment of piston displacement and pumping rate, enabling the device to adapt to changing preload and afterload conditions while maintaining reliable fluid displacement through controlled magnetic force application
Solution Approach 2:
The patent incorporates physiological sensors that monitor parameters such as arterial pressure, flow rate, and cardiac rhythm, feeding this information back to the control system. The controller adjusts the electromagnetic actuation parameters accordingly, allowing the pump to respond dynamically to changes in preload and afterload while maintaining reliable and appropriate fluid displacement
3Productivity
If high-speed piston actuation is used to increase pumping rate, then productivity is improved, but fluid hammer effects and hemolysis increase
Solution Approach 1:
The patent employs a carefully controlled periodic actuation of the drive piston, where the magnetic force is applied in controlled pulses rather than continuous high-speed motion. This periodic electromagnetic actuation allows the system to achieve the required pumping rate while smoothing out pressure fluctuations and eliminating fluid hammer effects that would occur with abrupt high-speed mechanical actuation
Solution Approach 2:
The patent replaces high-speed mechanical piston actuation with electromagnetic force application, allowing for smoother, more controlled acceleration and deceleration of the drive piston. This substitution eliminates the abrupt mechanical impacts that cause fluid hammer while maintaining the pumping rate through precisely controlled magnetic field variations
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
This configuration allows for variable stroke volume, reduces fluid hammer effects, and restores the heart's native sensitivity to preload and afterload, improving cardiac output and reducing the risk of complications like over-pumping and hemolysis.
Implementation Method 1
the electromagnet exerts a magnetic force on the drive piston
Implementation Method 2
the electric motor exerts a first magnetic force on the first piston; the magnetic ring exerts a second magnetic force on the first piston; and the first magnetic force opposes the second magnetic force
Data Source
AI summary
Systems and methods including a valve piston in a pumping chamber. The pumping chamber may include a pump inlet and a pump outlet in fluid communication with the pumping chamber. The valve piston may be configured to rotate between a first position within the pumping chamber and a second position outside of the pumping chamber.