Biological Component Measuring Device Calibration via Flow Path Valves
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Solution Overview
Problem
Conventional biological component-measuring devices, such as artificial endocrine pancreas devices, face inaccuracies due to variations in sample flow rates and sensor calibration, which are not adequately addressed by calibrating only the sensors, as other device components like pumps and sample channels also contribute to measurement errors.
Innovation Solution
The device incorporates a first and second flow path changeover valve system that allows for the introduction of a calibrating liquid to correct measurements, combined with a body fluid-diluting liquid channel to prevent coagulation and adjust component concentrations, and a flushing liquid channel for cleaning, enabling comprehensive calibration and accurate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only the sensor is calibrated periodically by removing the device from the patient, then the sensor accuracy is improved, but the measurement continuity is interrupted and the overall device accuracy remains compromised due to uncalibrated pumps and channels
Solution Approach 1:
The calibration process is segmented into multiple independent calibration liquids (first calibration liquid for zero-point calibration, second calibration liquid for span calibration) that can be introduced through separate calibration ports, allowing systematic calibration of different device components including pumps and channels in addition to the sensor
Solution Approach 2:
Calibration liquids serve as intermediary substances that flow through the entire measurement system (pumps, channels, sensor) to enable calibration of all components simultaneously without removing the device from the patient, thereby maintaining measurement continuity while improving overall accuracy
2Ease of repair
If the device is removed from the patient for sensor calibration, then calibration can be performed, but the measurement continuity is interrupted and time is lost
Solution Approach 1:
Multiple calibration ports are provided in advance at different locations in the system, allowing calibration liquids to be introduced at various points before they reach the sensor, enabling calibration to be performed without removing the device from the patient
Solution Approach 2:
The calibration system is designed to allow calibration operations to proceed continuously while the device remains in the patient, with calibration liquids flowing through the system without interrupting the normal measurement function, thus eliminating measurement interruption time
3Reliability
If comprehensive calibration of the entire device is implemented, then overall measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The calibration system is designed with multi-functionality where the same calibration liquid introduction mechanism serves multiple purposes: calibrating the pump flow rate, calibrating the channel transmission, and calibrating the sensor response, thereby reducing overall system complexity despite comprehensive calibration capability
Solution Approach 2:
The calibration functions for different device components (pump, channels, sensor) are merged into a single integrated calibration process using calibration liquids that flow through the entire system, eliminating the need for separate calibration procedures for each component
Data Source
AI summary
This invention provides a biological component-measuring device, enabling the operator to easily calibrate the entire device and capable of measuring biological components accurately, and a method for calibrating the device. The device measures a sample including a body fluid taken through a body fluid sampler by sending it with a pump through a sample channel to a sensor. The device further includes a calibrating liquid channel through which a calibrating liquid can be supplied to the sensor via the sample channel by a switching of a first flow path changeover valve placed in the sample channel at a location upstream of the pump and connected to the channel. The method includes introducing the calibrating liquid in the calibrating liquid channel, via other channels, into the sensor by switching the valve.