Blood Pump Inlet Guard and Thrust Bearing for Axial Stability
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Solution Overview
Problem
Current ventricular assist devices face challenges in maintaining axial stability of the impeller within the heart ventricle, particularly under varying pressure gradients, which can lead to axial motion and reduced efficiency in blood pumping.
Innovation Solution
The design incorporates a thrust bearing with a ceramic interface and a distal bearing housing that houses the thrust bearing, preventing axial motion of the axial shaft and ensuring low-friction operation, while also allowing for guidewire insertion and purging fluid flow through a continuous lumen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the impeller is allowed to move axially under varying pressure gradients, then the device can adapt to pressure changes, but axial stability is lost and pumping efficiency decreases
Solution Approach 1:
A thrust bearing is introduced as an intermediary component between the impeller and the housing to manage axial forces. The thrust bearing absorbs and redirects axial pressure variations, allowing the impeller to maintain stable axial position while the bearing handles the adaptive load variations.
Solution Approach 2:
The thrust bearing provides a counteracting force to balance axial pressure gradients. By positioning the thrust bearing to oppose axial motion, it creates a balancing mechanism that maintains impeller stability while accommodating pressure changes through the bearing's load-bearing capacity.
2Stability of the object's composition
If a thrust bearing is added to prevent axial motion, then axial stability is improved, but device complexity increases
Solution Approach 1:
The thrust bearing assembly is designed to perform multiple functions: providing axial stability, facilitating guidewire passage through its lumen, and enabling purging fluid flow. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall device complexity.
Solution Approach 2:
The thrust bearing is integrated within the existing housing structure, with its lumen nested within the housing bore. This nested configuration allows the thrust bearing to occupy minimal additional space and integrates smoothly with the overall device architecture, reducing the impact on device complexity.
3Productivity
If the inlet guard is placed distally to the impeller, then flow direction is optimized, but space occupancy increases
Solution Approach 1:
The inlet guard is designed as a flat, planar structure positioned perpendicular to the axial shaft, utilizing the radial dimension rather than extending axially. This dimensional approach allows the guard to define flow holes and optimize blood flow direction to the impeller while occupying minimal axial space within the constrained pump volume.
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 stabilizes the axial shaft, maintains efficient blood pumping, and reduces wear and friction, enhancing the device's performance and longevity by preventing axial movement and ensuring smooth operation under pressure variations.
Implementation Method 1
thrust bearing with a ceramic interface... ensuring low-friction operation
Data Source
AI summary
Apparatus and methods are described including an axial shaft configured for insertion into, and rotation within, a ventricle of a heart of a subject. An impeller is coupled to the axial shaft and a frame surrounds the impeller. A pump-outlet tube surrounds the frame such that, as the axial shaft rotates, the impeller pumps blood proximally, from the ventricle, through the pump-outlet tube. A flat inlet guard, which is shaped to define one or more holes, is disposed around, and perpendicular to, the axial shaft and within the frame distally to the impeller, such that the blood flows to the impeller via the holes. Other applications are also described.