Fluid Concentration Measurement Using Dual Light Path Ratios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fluid concentration measuring devices face challenges in accurately measuring the concentration of fluids like blood or chemicals flowing through light-transmissive, deformable ducts, such as resin tubes, due to variations in inner diameter and wall thickness, which affect light path length and precision.
Innovation Solution
A fluid concentration measuring device is designed with a light receiving part fixed diametrically opposite to the light supply part, maintaining a right-angle light path perpendicular to the duct's longitudinal direction, allowing for multiple light path distances to be set between the parts, enabling precise concentration measurement using the Beer-Lambert law.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light is passed through a light-transmissive duct with deformable walls to measure fluid concentration, then the measurement can be applied to medical and chemical fields, but the inner diameter and wall thickness are difficult to measure and vary due to deformation, making concentration measurement extremely difficult or impossible
Solution Approach 1:
The invention changes the measurement parameter from absolute light path length to relative light path length ratio. By measuring at two different positions and forming a ratio, the system eliminates the need to know absolute dimensions of the deformable duct, thereby resolving the contradiction between adaptability to deformable ducts and measurement precision.
Solution Approach 2:
The invention introduces an intermediary measurement approach by using two light receiving parts at different positions. The ratio of light intensities from these two positions serves as an intermediary parameter that indirectly determines fluid concentration without requiring direct measurement of difficult-to-obtain duct dimensions.
2Ease of operation
If the light path inside the duct wall is set perpendicular to the duct wall at each light receiving part, then calculation can be performed, but the actual light path extends obliquely across the duct wall and the inclination angle varies at different refractive indexes, resulting in reduced calculation precision
Solution Approach 1:
The invention converts the harmful effect of oblique light paths with varying inclination angles into a beneficial measurement approach. By measuring light intensity at two different positions and using the ratio, the system accounts for the oblique paths without requiring precise knowledge of the inclination angles, thereby maintaining calculation feasibility while improving precision.
3Measurement precision
If multiple light receiving parts are provided at different positions to account for varying light paths, then measurement can be performed, but the device complexity increases
Solution Approach 1:
The invention segments the measurement function into two distinct light receiving parts positioned at different locations. This segmentation allows the system to measure light intensity at multiple positions independently, enabling precise concentration determination through ratio calculation while maintaining a relatively simple overall device structure.
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 configuration allows for high-precision measurement of fluid concentration in deformable ducts by eliminating the influence of duct dimensions and enabling real-time, continuous monitoring of fluid concentration changes.
Implementation Method 1
the concentration of the treatment liquid is obtained from the light intensity based on the Beer-Lambert law
Implementation Method 2
light from a light source is supplied to one of the light-transmissive portions which has a light path length according to the properties of the treatment liquid; the light having passed through the treatment liquid at that light-transmissive portion is received by a light detector and the intensity of the light is measured
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
Problem to be solved To achieve high-precision measurement of the concentration of a fluid, such as blood or a chemical, flowing through a duct having a light-transmissive, deformable duct wall, such as a resin tube, by not measuring light which has passed through a light path extending obliquely across the longitudinal direction of the duct. Solution There is provided a fluid concentration measuring device which measures the concentration of a fluid flowing through a duct having a light-transmissive, deformable duct wall, the device including: a light source which supplies light into the duct from a light supply part on the surface of the duct; a light receiving element which receives the light, which has been supplied and passed through the wall of the duct and the fluid inside the duct, at a light receiving part located on the opposite side in the diametrical direction of the duct relative to the light supply part, and outputs a signal indicating the intensity of the light; light path distance setting means which sets a plurality of light path distances between the light supply part and the light receiving part; and fluid concentration output means which, from the light intensity at the light receiving part located at each of the plurality of light path distances, obtains a plurality of relational expressions, which indicate the relation between the light intensity and the fluid concentration when the light from the light supply part is received by the light receiving part over each of the light path distances, based on the Beer-Lambert law, and obtains the fluid concentration from the light intensity at the light receiving part based on the relational expressions for the plurality of light path distances and outputs the fluid concentration.