Ventilator Flow Sensor Error Detection via Delta Signal Comparison
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Solution Overview
Problem
Existing ventilation devices for artificial respiration struggle to accurately detect malfunctions in flow sensors, particularly due to differences in measured values between internal and external sensors caused by tube elasticity, leading to incomplete error detection.
Innovation Solution
The control device compares change values of measurement signals from both flow sensors to detect errors more reliably, allowing for earlier detection of slight changes in opposite directions, and uses summation of change values to assess sensor operation, enabling independent error detection without relying on signals from both sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control device compares measured values of two different flow sensors to detect errors, then error detection capability is improved, but the detection reliability deteriorates due to tube elasticity causing different measured values even with the same effective breathing gas flow
Solution Approach 1:
The patent changes the parameter being compared from absolute flow values to changes in flow values (delta values). By comparing the change in flow measured by the distal sensor with the change in flow measured by the proximal sensor, the system can detect sensor errors while accounting for the elastic tube effects that cause absolute value discrepancies. This parameter transformation allows error detection without being confounded by the known physical effects of tube elasticity.
2Reliability
If the control device uses change values instead of measured values for error detection, then error detection reliability is improved, but the complexity of the detection algorithm increases
Solution Approach 1:
The control device performs preliminary calculations by determining the change in flow values (delta values) from the measured flow values before comparing them. This preliminary action of calculating differences simplifies the subsequent comparison operation, as the system only needs to check whether the change values match within a tolerance range, rather than dealing with complex absolute value comparisons that account for tube elasticity.
Data Source
AI summary
The present artificial respiration ventilator (10) comprises, inter alia, a flow sensor arrangement (44, 48) for quantitatively detecting a gas flow in a breathing line arrangement (30), comprising a distal flow sensor (48) located farther from the patient end of the ventilation line arrangement (30). and a proximal flow sensor (44) located closer to the patient end of the ventilation line arrangement (30), and has a control device (18) at least for processing measurement signals of the flow sensor arrangement (44, 48), wherein the control device (18) is designed for error detection based on the measurement signals of the distal (48) and/or the proximal sensor (44). According to the invention, the control device (18) is designed to detect an error of the flow sensor arrangement (44, 48) on the basis of a comparison of a change value (62, 76) of a measurement signal (54, 58, 68, 72) of the one flow sensor (44) with a change value (60, 74) of a measurement signal (52, 56, 66, 70) of the respective other flow sensor (48) or/and with a measurement signal (54, 58, 68, 72) of the one flow sensor (44).