Blood Collection Pressure Sensing With Creep Error Correction

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Solution Overview

Problem

Existing biological component collection systems face challenges in accurately measuring internal pressures due to measurement errors caused by creep deformation in load detection units, particularly during the collection and returning operations of the first cycle.

Innovation Solution

The system employs a configuration where the flow path cross-sectional area of a second load detection unit is greater than that of the first, minimizing creep deformation, and uses a correction method to align first and second internal pressure calculations, ensuring accurate pressure measurement by calibrating the first detection signal with the second, which is less prone to deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a load detection unit with small flow path cross-sectional area is used, then the device structure can be compact, but creep deformation occurs more easily causing measurement errors

Engineering Contradiction:
Improvedevice structure compactnessVSAvoidinternal pressure measurement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent divides the pressure measurement function into two separate load detection units: a first load detection unit with smaller flow path cross-sectional area for compactness, and a second load detection unit with larger flow path cross-sectional area for accurate measurement. By segmenting the measurement function across two units with different characteristics, the system achieves both compact structure and high measurement precision.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the first load detection unit is used for pressure measurement, then the device structure remains compact, but measurement errors occur due to creep deformation during collection and returning operations

Engineering Contradiction:
Improvedevice structure simplicityVSAvoidmeasurement reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the second load detection unit, which provides reliable measurement data, is used to correct the output of the first load detection unit. The correction unit receives detection signals from both units, compares them, and applies correction to compensate for creep deformation errors in the first unit, thereby maintaining measurement reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the operational parameters of the load detection units by using two different flow path cross-sectional areas. The first unit operates with a smaller area for compactness, while the second unit operates with a larger area to minimize creep deformation. This parameter differentiation allows each unit to serve its specific function optimally.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If creep deformation correction is implemented using a second load detection unit, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improveinternal pressure measurement accuracyVSAvoidsystem structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The second load detection unit serves multiple functions: it acts as both a primary measurement device for accurate pressure detection and as a reference unit for correcting creep deformation errors in the first load detection unit. This multi-functionality reduces the need for additional correction mechanisms, thereby limiting the increase in system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach allows for precise measurement of circuit internal pressure, enhancing accuracy and reducing measurement errors, while also enabling a compact device structure and simplified operation by integrating a filter function into the second load detection unit.

Implementation Method 1

a first load detecting unit that presses on a wall portion of the first applied load measurement unit in a device mounted state in which the biological component collection device is mounted in the separation device

Methodology Applied
Scientific EffectLoad detection through pressing: Mechanical Force

Implementation Method 2

a second load detecting unit that presses on a wall portion of the second applied load measurement unit in the device mounted state

Methodology Applied
Scientific EffectLoad detection through pressing: Mechanical Force

Implementation Method 3

a first internal pressure calculation unit that calculates first internal pressure of the first applied load measurement unit based on a first detection signal from the first load detecting unit

Methodology Applied
Scientific EffectPressure calculation from load measurement: Pascal's Law

Implementation Method 4

a second internal pressure calculation unit that calculates second internal pressure of the second applied load measurement unit based on a second detection signal from the second load detecting unit

Methodology Applied
Scientific EffectPressure calculation from load measurement: Pascal's Law

Implementation Method 5

a correction unit that corrects the first internal pressure calculation data in a manner so that the first internal pressure calculated by the first internal pressure calculation unit becomes equal to the second internal pressure calculated by the second internal pressure calculation unit

Methodology Applied
Scientific EffectCreep deformation compensation: Creep

Data Source

PatentEP3773793B1Biological component collection system and flow path internal pressure acquisition method
Publication Date: 2025.12.24 TERUMO KK
  • EP3773793B1 patent drawingFigure 1
  • EP3773793B1 patent drawingFigure 2
  • EP3773793B1 patent drawingFigure 3

AI summary

A blood component collection system (10) includes a first internal pressure calculation unit (110) adapted to calculate a first internal pressure of a first pressed portion (60) using first calibration curve data (118), a second internal pressure calculation unit (112) adapted to calculate a second internal pressure of a second pressed portion (62) using second calibration curve data (120), and a correction unit (114) adapted to correct the first calibration curve data (118) in a manner so that the first internal pressure becomes equal to the second internal pressure in a state in which operation of a collection and returning pump (100) is stopped during at least one of a collection operation and a returning operation of a first cycle.