Blood Pump Drive Shaft Cooling for Motor Heat Isolation
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Solution Overview
Problem
Temporary blood pump devices face safety risks due to heat generation from electric motors, which can exceed safe patient contact temperatures if not effectively cooled.
Innovation Solution
An external water jacket or annular structure is used to cool the electric motor by pumping fluid through it, actively removing excess heat generated by the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an external motor is used to power the blood pump impeller, then the pump can be delivered percutaneously through the femoral artery to the ascending aorta, but the motor generates excessive heat that exceeds safe patient contact temperatures
Solution Approach 1:
A drive shaft serves as an intermediary component, transmitting rotational motion from the external motor through the percutaneous delivery system to the impeller. This allows the motor to be positioned externally while still powering the pump, managing the heat issue by separating the motor from the patient-contacting components.
Solution Approach 2:
The motor is extracted from the internal pump structure and positioned externally, allowing it to be separated from the patient-contacting elements. This extraction removes the heat source from proximity to the patient while maintaining the motor's functional role in driving the impeller.
2Device complexity
If the motor is integrated into the device, then the structure is more compact, but the heat generated by the motor creates safety risks for patient contact
Solution Approach 1:
The motor is extracted from the integrated device structure and repositioned externally. This separation maintains a compact pump design while removing the heat-generating motor from proximity to patient-contacting components, thereby eliminating the safety risk.
Solution Approach 2:
The system is segmented into distinct functional components: the external motor, the drive shaft transmission system, and the internal pump assembly. This segmentation allows the motor to be isolated from the patient-contacting elements while maintaining functional integration through the drive shaft.
3Object-affected harmful factors
If active cooling is implemented to remove motor heat, then patient safety is improved, but the device complexity increases
Solution Approach 1:
The drive shaft acts as a thermal intermediary, conducting heat away from the motor through its rotation and contact with cooling fluids. This passive thermal management approach simplifies the cooling system compared to active refrigeration systems while still effectively removing motor heat.
Solution Approach 2:
The rotating drive shaft performs self-cooling through its continuous rotation, which facilitates heat transfer from the motor to the surrounding cooling environment. This self-service cooling mechanism eliminates the need for complex active cooling 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
Effectively maintains patient-contacting surfaces below safe temperature thresholds, reducing the risk of patient and operator safety hazards.
Implementation Method 1
An external water jacket or annular structure is used to cool the electric motor by pumping fluid through it, actively removing excess heat generated by the motor
Data Source
AI summary
A cooling system for a rotational medical device such as a blood pump comprising an electric motor, a rotational drive shaft and an impeller. The cooling system comprises at least one active fluid pump for moving fluid distally within an outer fluid flow channel to a point proximal of the drive shaft's connection with the impeller where the fluid is deflected and urged into a fluidly connected inner fluid flow channel. A portion of the fluid in the outer fluid flow channel is pumped toward the impeller and the remaining fluid flows proximally through the inner fluid flow channel and along the outer surface of the drive shaft, thereby removing frictional heat from the rotating drive shaft. Next, the fluid is urged to bathe the outer surface of the electric motor to remove heat from the motor. Finally, the heated fluid is removed from the system.