Blood Collection Cassette Pressure Sensing With Dual Load Detection
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Solution Overview
Problem
Existing blood component collection systems face challenges in accurately measuring circuit internal pressure, particularly in negative and positive pressure regions, leading to measurement errors due to changes in reaction forces over time.
Innovation Solution
A blood component collection cassette with a first and second load detector, utilizing soft material sheets to form flow paths and pressure-receiving portions, allows for accurate measurement by detecting and subtracting reaction forces to calculate internal pressure, and includes a method to correct for errors due to changing reaction forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single load detector is used to measure circuit internal pressure, then the device complexity is reduced, but measurement precision deteriorates due to inability to compensate for reaction force changes
Solution Approach 1:
The pressure measurement function is segmented into two independent load detectors: one for measuring the pressing force on the first flow path and another for measuring the reaction force of the pressure-receiving portion. This segmentation allows independent measurement of each force component, enabling precise calculation of circuit internal pressure by subtracting the reaction force from the pressing force, thereby resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
A reaction force measurement mechanism is introduced as an intermediary element to indirectly capture the changing elastic properties of the pressure-receiving portion. By measuring the reaction force separately and using it as a compensation parameter, the system can account for material degradation over time without requiring direct measurement of every variable, thus improving precision while maintaining manageable complexity.
2Ease of manufacture
If soft material sheets are used to form flow paths and pressure-receiving portions, then ease of manufacture is improved, but measurement precision deteriorates due to changing reaction forces over time
Solution Approach 1:
The system transitions from a static measurement approach to a dynamic compensation approach. The reaction force measurement continuously tracks changes in the soft material's elastic properties over time, allowing the system to adapt to material degradation. This dynamic adjustment maintains measurement precision despite the inherent limitations of soft, degradable materials, while preserving the manufacturing advantages of using such materials.
Solution Approach 2:
A feedback mechanism is implemented where the measured reaction force is used to compensate for changes in the pressure-receiving portion's elastic properties. The system continuously monitors the reaction force and adjusts the pressure calculation accordingly, creating a closed-loop control that maintains accuracy despite material degradation. This feedback approach allows the use of soft, easy-to-manufacture materials while preserving measurement precision through active compensation.
3Adaptability or versatility
If pressure-receiving portions are made from elastic materials, then adaptability is improved for different pressure conditions, but reliability deteriorates due to degradation of elastic properties over time
Solution Approach 1:
The system employs continuous feedback from the reaction force load detector to monitor and compensate for elastic property degradation. By measuring the reaction force at each measurement point and using it to correct the pressure calculation, the system maintains reliability over time despite the inherent degradation of elastic materials. This feedback mechanism allows the pressure-receiving portion to remain adaptable to different pressure conditions while ensuring consistent, reliable measurements throughout the device's operational life.
Solution Approach 2:
The patent replaces reliance on the mechanical integrity of elastic materials with an electrical/electronic measurement and compensation system. Instead of depending on the elastic material's properties to remain constant, the system uses load detectors to measure forces and computationally compensate for material degradation. This substitution transfers reliability from the mechanical domain (material properties) to the measurement domain (force sensing and calculation), maintaining adaptability while improving long-term reliability.
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 precise measurement of circuit internal pressure in both negative and positive regions, reducing measurement errors by real-time correction of reaction forces, and allows for cost-effective manufacturing.
Implementation Method 1
a first load detector and a second load detector, the flow path has a first line through which blood flows when the blood component separation device is in operation
Implementation Method 2
the cassette body includes a first line forming member made of a soft material to form the first line and a second line forming member made of a soft material to form the second line
Data Source
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AI summary
Provided is a blood component collection cassette, a blood component collection kit, a blood component collection system, and a flow path internal pressure detection method capable of accurately measuring a circuit internal pressure in negative pressure and positive pressure regions. A flow path (42) formed in a cassette body (40) of a blood component collection cassette (28) has a first line (42a) through which blood flows when a blood component separation device is in operation, and a second line (42b) through which blood does not flow when the blood component separation device is in operation. A first line forming member (54) is provided with a first pressure-receiving portion (60) pressed by a first load detector (88) attached to the blood component separation device. A second line forming member (56) is provided with a second pressure-receiving portion (62) pressed by a second load detector (90) attached to the blood component separation device.