Sensor Assembly Calibration for Extracorporeal Circulation
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Solution Overview
Problem
In extracorporeal circulation management devices, pressure sensors integrated into the blood circuit cannot perform accurate calibration after the circuit is filled with fluid, due to applied differential pressure.
Innovation Solution
A sensor assembly with a pressure sensor element and a storage unit that stores calibration information obtained when the sensor is open to atmospheric pressure, allowing continuous calibration of measured values even after the blood circuit is filled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the pressure sensor is built in the blood circuit, then the device can be used for long time without thrombus formation from branch pipes, but calibration cannot be performed correctly after the blood circuit is filled with fluid due to applied differential pressure
Solution Approach 1:
The calibration value is determined in advance during manufacturing when the pressure sensor element can be accessed and calibrated. This preliminary calibration stores reference data that enables accurate measurements even after the sensor is permanently integrated into the blood circuit and cannot be accessed for recalibration.
2Measurement precision
If the pressure sensor is disposed at a point where both sides can be opened to atmospheric pressure for calibration, then calibration can be performed, but a branched branch pipe may lead to thrombus formation
Solution Approach 1:
The sensor is calibrated during manufacturing before being permanently integrated into the blood circuit. This preliminary calibration eliminates the need for branch pipes that would be required for post-installation calibration, thereby preventing thrombus formation while maintaining measurement accuracy through stored calibration data.
3Device complexity
If the pressure sensor element is integrated into the blood circuit, then the device structure is simplified and thrombus formation is prevented, but the sensor cannot be calibrated after priming is performed
Solution Approach 1:
The pressure sensor element is calibrated during the manufacturing process before being integrated into the blood circuit. The calibration data is stored in memory, enabling the sensor to provide accurate measurements throughout its operational life without requiring subsequent calibration operations that would necessitate circuit disassembly or branch pipes.
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
Enables continuous calibration of pressure sensor measurements within the extracorporeal circulation management device, ensuring accurate pressure readings even after the blood circuit is primed and filled with fluid.
Implementation Method 1
calibrate (zero-value correction) a deviation unique to the pressure sensor due to a variation in resistance of the strain gauge
Data Source
AI summary
A sensor assembly stores calibration information thereon even after a blood circuit is filled with fluid. A pressure sensor element 42 measures a value of pressure in a fluid flow channel 45. A storage unit 51 which is integrated with sensor element 42 stores, as calibration information, a calibration value determined in advance according to a value indicated by the pressure sensor element 42 in a state in which the pressure sensor element 42 is opened to atmospheric pressure and in which the internal pressure in a fluid flow channel 45 of the pressure sensor element 42 is equal to the atmospheric pressure. Measured pressure values and the calibration value are provided to a control unit which adjusts the measured values on the basis of the calibration information.