Gas Bubble Detection via Sensor Signal Kinetics
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Solution Overview
Problem
Existing gas sensors in clinical diagnosis systems, such as blood gas analyzers, face measurement errors due to gas bubbles in aqueous samples, which are not efficiently detected by current methods, especially in automated analyzers with small sample volumes.
Innovation Solution
A method for detecting gas bubbles in contact with the sensor's sensitive region involves setting a gas partial pressure different from the expected value, exposing the sensor to the liquid until a constant signal is recorded, and analyzing signal variations over time to determine the presence of bubbles, utilizing the response kinetics of optical-chemical or electrochemical sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas sensors are used in clinical diagnosis systems, then gas concentration measurement is enabled, but measurement errors occur due to gas bubbles in aqueous samples
Solution Approach 1:
The patent applies preliminary action by establishing a known gas partial pressure condition before introducing the sample liquid. The sensor is pre-equilibrated with a gas phase having a defined partial pressure of the target gas, creating a controlled initial state that enables detection of bubble-induced disturbances before they affect the actual measurement
Solution Approach 2:
The patent implements feedback by continuously monitoring the sensor signal over time and comparing it against expected signal patterns. The system evaluates whether signal variations fall within normal measurement ranges or indicate the presence of gas bubbles, enabling real-time detection and correction of measurement errors
2Productivity
If automated analyzers with small sample volumes are used, then productivity is improved, but gas bubble detection becomes more difficult
Solution Approach 1:
The patent applies parameter changes by utilizing dynamic temporal analysis of sensor signals rather than static measurements. By examining how the sensor response evolves over time following sample introduction, the system can detect the characteristic signature of gas bubbles even in small volumes, maintaining high productivity while improving detection capability
Solution Approach 2:
The patent transitions from spatial detection methods to temporal detection by analyzing the time dimension of sensor responses. Instead of attempting to physically detect bubbles in the small sample volume, the system detects their presence through temporal patterns in the sensor signal, effectively adding a time dimension to the detection process
3Reliability
If gas partial pressure is set different from expected value, then bubble detection is enabled, but additional measurement steps are required
Solution Approach 1:
The patent merges the bubble detection function with the existing gas concentration measurement function. The same sensor and measurement chamber used for determining gas partial pressure are also used to detect gas bubbles by analyzing temporal signal patterns, combining two functions into a single integrated system rather than requiring separate detection mechanisms
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 method allows for the reliable detection of even small gas bubbles without modifying the measuring chamber, enabling appropriate countermeasures to prevent measurement errors by distinguishing bubble-induced signal changes from other sample variations.
Implementation Method 1
the gas molecules to be determined diffuse from an usually aqueous exterior solution or a gas phase into the interior electrolyte chamber of the sensor via a gas-permeable but essentially fluid- and ion-impermeable membrane
Implementation Method 2
the oxygen which has diffused through the membrane from the measurement medium into the interior electrolyte chamber, is consumed by electrochemical reduction at the working electrode and an electric current corresponding to the substance consumed flows
Implementation Method 3
at least one layer contains a dye whose optical properties (e.g., absorption, luminescence, etc.) are dependent on an analyte contained in the sample medium
Implementation Method 4
at least one layer contains a dye whose optical properties (e.g., absorption, luminescence, etc.) are dependent on an analyte contained in the sample medium
Data Source
AI summary
A method for detecting the presence or absence of a gas bubble in an aqueous liquid is provided comprising providing a sensor positioned within a measuring chamber, wherein the sensor is configured to determine the concentration of a gaseous component dissolved in a liquid, the sensor comprising a sensitive region; setting a gas partial pressure at the sensor, wherein the gas partial pressure differs from an expected value of the gas partial pressure of the gaseous component of a liquid to be measured; exposing the sensor to the liquid to be measured; resting the liquid until standstill is attained; recording a signal from the sensor as a function of time until the signal becomes constant; and detecting the presence or absence of a gas bubble from the variation of the signal over time. The gas bubble, if present, is in at least partial contact with the sensitive region of the sensor.