Coaxial Pneumatic Driver for Artificial Heart
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Solution Overview
Problem
Current portable pneumatic drivers for artificial hearts are cumbersome, unreliable, and unable to provide the correct pressure balance between the left and right ventricles, limiting their portability and effectiveness in maintaining proper operating pressures for the pulmonary and systemic circuits.
Innovation Solution
A portable pneumatic driver design featuring two coaxial cylindrical pumping chambers with disk-shaped pistons connected through a tube, allowing for independent and coordinated periodic actuation, with limit check valves to manage pressure and vacuum, enabling efficient blood ejection and filling while minimizing size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If current portable pneumatic drivers are used for artificial hearts, then the device can be made portable, but the reliability and ability to provide correct pressure balance between ventricles deteriorates
Solution Approach 1:
The pneumatic driver is divided into two separate pumping chambers (first and second chambers) that can independently generate and regulate pressure for the right and left ventricles respectively. Each chamber has its own pressure regulation mechanism, allowing independent pressure control to maintain proper pressure balance between the two ventricles while keeping the overall device portable.
2Device complexity
If a single pumping chamber is used, then the device complexity is reduced, but the ability to provide coordinated periodic actuation and pressure balance between left and right ventricles deteriorates
Solution Approach 1:
Two pumping chambers are merged into a single integrated pneumatic driver unit with a common housing and shared control systems. This combining approach allows coordinated periodic actuation of both ventricles from a single portable device while maintaining the ability to independently regulate pressure in each chamber, thus providing both structural simplicity and functional coordination.
3Reliability
If limit check valves are added to manage pressure and vacuum, then the reliability of blood ejection and filling is improved, but the device complexity increases
Solution Approach 1:
Limit check valves are integrated into the pneumatic driver system to automatically regulate and limit the maximum pressure and vacuum levels in each pumping chamber during operation. These valves self-regulate the pressure parameters without requiring external control systems, ensuring reliable blood ejection and filling while maintaining a relatively simple device structure through automatic pressure management.
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 provides reliable, portable, and efficient operation, achieving the necessary pressure balance between ventricles, allowing for complete blood ejection and partial filling, thus enhancing the portability and usability of the artificial heart.
Implementation Method 1
periodic actuation pressure differentials to drive blood flow
Implementation Method 2
The pump chambers are sized and configured to provide efficient compression of gas to be supplied to the artificial heart
Data Source
AI summary
A pneumatic pump comprises two coaxial cylindrical pumping chambers, each enclosing a piston connected to the other through a partition by a tube, thereby forming a monolithic piston assembly that is driven axially by a common electrical actuator providing reciprocating motion. The volume in the bottom chamber is selected as needed to provide the desired pressure in the left ventricle of an artificial heart driven by the pump. The diameter of the tube connecting the pistons is selected such that the stroke volume of the top chamber is reduced with respect to that of the bottom chamber as needed to match the reduced pressure requirements of the right ventricle of the artificial heart. Check valves are used in each chamber to ensure venting of excess pressure during the blood ejection phase and to limit the vacuum during the fill phase.