Device for the measurement of carbon dioxide in a working gas
Inventors
Ghelli, Nicola • Fontanili, Paolo • CORBELLI, Marco • BELLANCINI, Michele • Comai, Guido
Assignees
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Publication Number
US-12246120-B2
Publication Date
2025-03-11
Expiration Date
Abstract
A device for the measurement of carbon dioxide in a working gas comprises: a tubular body inside which a working gas is conveyed; at least one emitter of an optical signal arranged at the tubular body; at least one receiver of the optical signal arranged at the tubular body on the opposite side of the emitter; heating unit arranged at least one of the emitter and the receiver; wherein the device comprises at least one temperature sensor positioned in the proximity of the heating unit, at least one control unit operatively connected to the emitter, to the receiver, to the heating unit and to the sensor, the control circuit unit comprising correction unit which are configured to correct the value of the optical signal detected by the receiver depending on the temperature measured by the temperature sensor.
Core Innovation
A device for measurement of carbon dioxide in a working gas uses a tubular body inside which the working gas is conveyed. At least one optical emitter and at least one optical receiver are arranged at the tubular body on opposite sides to transmit an optical signal through the tubular body. Heating means are located to be arranged at the emitter and/or the receiver to prevent condensation on the optical components.
A temperature sensor is positioned in proximity of the heating means, and a control unit corrects the value of the optical signal detected by the receiver based on the temperature measured by the temperature sensor. The control unit calculates a filtered optical signal (Sf) as an average of signals received in a first dynamic time range, and calculates a filtered temperature (Tf) as an average temperature measured in a second dynamic time range. The corrected optical signal (Sc) is calculated using Sc = Sf + (Tr − Tf)·C, where Tr is a pre-settable reference temperature and C is a pre-settable coefficient.
The corrected optical signal (Sc) is processed to determine an amount of carbon dioxide present in the working gas passing through the tubular body. The concept is used in a medical extracorporeal blood circulation circuit with a blood oxygenator having working-gas inlet and outlet channels, where the tubular body is arranged at the working-gas outlet channel.
Measuring means for working-gas flow rate may be used so that the control unit can determine a percentage of carbon dioxide removed from blood based on the flow rate and the corrected optical signal (Sc).
Claims Coverage
The document provides coverage for at least two independent claims: a device claim and a method claim. Across these independents, the core inventive features include optical CO2 measurement through a tubular body combined with heating, proximity temperature sensing, and temperature-dependent correction using filtered averages over dynamic time ranges with a correction formula using a reference temperature and coefficient.
Optical CO2 measurement through a tubular body
A device comprising a tubular body inside which the working gas is conveyed, at least one emitter of an optical signal arranged at the tubular body, and at least one receiver of the optical signal arranged at the tubular body on a side of the emitter, wherein the emitter and receiver transmit/receive the optical signal through the tubular body.
Heating of emitter/receiver with proximity temperature sensing
Heating means arranged to be located either at the emitter or at the receiver, and at least one temperature sensor positioned in a proximity of the heating means to measure temperature of the heated emitter and/or heated receiver.
Temperature-dependent correction using filtered optical and temperature averages
A control unit operatively connected to the emitter, receiver, heating means, and temperature sensor, wherein correction means correct the detected optical signal value based on the measured temperature; the correction means calculate a filtered optical signal (Sf) as an average over a first dynamic time range, calculate a filtered temperature (Tf) as an average over a second dynamic time range, and calculate a corrected optical signal (Sc) according to Sc = Sf + (Tr − Tf)·C with a pre-settable reference temperature (Tr) and a pre-settable coefficient (C).
Processing corrected optical signal to determine CO2 amount in working gas
The control unit processes the corrected optical signal (Sc) to determine an amount of carbon dioxide present in the working gas which passes through the tubular body.
Dynamic time-range averaging in method for CO2 measurement
A method including calculation of a filtered optical signal (Sf) corresponding to the average of optical signals received by a receiver in a first dynamic time range, calculation of a filtered temperature (Tf) corresponding to the average of temperature measured in a second dynamic time range, setting up a reference temperature (Tr), setting up a predefined coefficient (C), and calculating the corrected optical signal (Sc) according to Sc = Sf + (Tr − Tf)·C.
Extracorporeal blood circulation integration for CO2 removal percentage
In a circuit comprising extracorporeal blood circulation equipment with a blood oxygenator having blood inlet and outlet ports and working-gas inlet and outlet channels, providing a tubular body connected to the working gas outlet channel so that measurement of carbon dioxide in the working gas supports determination of an amount or percentage of carbon dioxide removed from blood.
Across the independent device and method claims, the main inventive elements are optical emitter/receiver measurement of carbon dioxide through a tubular body conveying the working gas, heating of the optical elements with nearby temperature sensing, temperature-dependent correction using filtered optical and filtered temperature averages over dynamic time ranges, and calculating a corrected optical signal with Sc = Sf + (Tr − Tf)·C using a reference temperature and coefficient. The downstream processing supports determining CO2 amount and, in the extracorporeal blood circulation context, a CO2 removal-related percentage.
Stated Advantages
Improved reliability/accuracy by accounting for heating-induced signal changes via temperature correction of the received optical signal.
Documented Applications
Medical extracorporeal blood circulation circuit including a blood oxygenator, where carbon dioxide measurement in working gas at a working-gas outlet channel is used to support calculation of carbon dioxide removed from blood.
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