Device for detecting concentration of trace gas in respiratory gas

Abstract

The device comprises a light source unit (1), a light cavity (2), a sensor unit (3) and a processor unit (4), measuring light emitted by the light source unit is projected into the light cavity, a gas inlet (5) is formed in the end, close to the light source unit, of the light cavity and connected with a gas nozzle (8), and a gas outlet (6) is formed in the end, close to the sensor unit, of the light cavity and connected with the gas nozzle (8). The sensor unit measures a measurement light absorption spectrum transmitted by breathing gas penetrating through the light cavity, the output of the sensor unit is electrically connected with the processor unit, and the processor unit is electrically connected with the light source unit and the display (7); the sensor unit comprises a first sensing unit (31) and a second sensing unit (32), and the processor unit obtains a first detection signal and a second detection signal, performs difference calculation to obtain a light intensity difference, and further obtains the gas concentration of a to-be-detected substance existing in breathing gas. According to the invention, the trace gas detection precision is improved.

Description

Technical Field

[0001] The invention relates to a gas detection device, in particular to a detection device for trace gas concentration in respiratory gas. Background Art

[0002] There are many volatile organic compounds (VOCs) in human breath. Diagnosing human diseases based on volatile organic compounds in breath has a long history. By detecting various trace gas components in human breath, we can provide a deep understanding of the human body's conditions in various biochemical processes, which is of great significance for early disease diagnosis.

[0003] Diabetes is a complex metabolic disorder caused by an absolute or relative lack of insulin. The acetone level in the blood of diabetic patients will increase significantly, and the acetone concentration in the breath can reflect the metabolic status of diabetic patients to some extent. In the blood of healthy people, the acetone content always remains at a certain level.

[0004] Existing instruments for measuring the acetone content in the breath of diabetic patients mainly use gas chromatography and mass spectrometers, flame ionization measuring instruments, etc., but these measuring devices have high production costs, complex designs, large volumes and heavy weights.

[0005] Chinese utility model patent CN213658572U discloses a real-time monitoring device for acetone content in breath for diabetes detection, including a monitoring wristband body, elastic straps are provided on the left and right sides of the monitoring wristband body, a display screen is provided on the front top of the monitoring wristband body, mounting holes are provided on the left and right sides of the front bottom of the monitoring wristband body, and detection components are installed in the two sets of mounting holes. During detection, the baffle is moved so that it is not blocking the air nozzle, and the acetone content can be detected by blowing from the air nozzle, which is convenient to use. The patent is provided with an infrared light source and a light detector, the infrared light source is used to emit infrared light and irradiate the exhaled gas in the gas container, and the light detector is used to detect the light absorption signal from the exhaled gas in the gas container, and send the light absorption signal to the AD converter, so as to quickly and accurately measure the acetone content in the breath of diabetic patients. The patent uses a single infrared light source, which may not fully excite the gas molecules of the breath, affecting the sensitivity of trace gas detection, and is easily affected by environmental factors such as temperature and humidity, resulting in a decrease in detection accuracy. Summary of the invention

[0006] The object of the present invention is to provide a detection device for the concentration of trace gases in breath. The detection device utilizes the absorption characteristics of gas molecules of the substance to be measured in breath for infrared light of a specific wavelength, performs differential measurement on the gas, and processes the data through a processing unit, thereby distinguishing the substance to be measured and detecting the gas concentration of the substance to be measured, improving the detection accuracy of trace gases.

[0007] In order to achieve the above technical object, the present invention adopts the following technical solution:

[0008] A detection device for the concentration of trace gases in breath includes a light source unit, an optical cavity, a sensor unit, and a processor unit. The measurement light emitted by the light source unit is projected into the optical cavity. A gas inlet is opened at the end of the optical cavity close to the light source unit, and the gas inlet is connected to a gas nozzle. A gas outlet is opened at the end of the optical cavity close to the sensor unit. The sensor unit measures the absorption spectrum of the measurement light transmitted through the breath gas in the optical cavity. The sensor unit outputs and is electrically connected to the processor unit, and the processor unit is electrically connected to the light source unit;

[0009] The sensor unit includes a first sensing unit and a second sensing unit.

[0010] The first sensing unit includes a first filter and a first sensor. The first filter allows a first part of the light with wavelengths within the first wavelength range of the gas measurement light absorption spectrum in the optical cavity to pass through; the first sensor is arranged downstream of the first filter, receives the first part of the light passing through the first filter, and outputs a first detection signal indicating the first part of the light in real time;

[0011] The second sensing unit includes a second filter and a second sensor. The second filter allows a second part of the light with wavelengths within the second wavelength range of the gas measurement light absorption spectrum in the optical cavity to pass through; the second sensor is arranged downstream of the second filter, receives the second part of the light passing through the second filter, and outputs a second detection signal indicating the second part of the light in real time;

[0012] The processor unit is electrically connected to the first sensor and the second sensor, obtains the first detection signal and the second detection signal, performs differential calculation to obtain the light intensity difference, and further obtains the gas concentration of the substance to be measured present in the breath gas.

[0013] The light source unit is an infrared light source, and the wavelength range of the infrared rays emitted by the infrared light source includes the first wavelength range and the second wavelength range.

[0014] The first wavelength range is from 7.1 μm to 7.5 μm, and the second wavelength range is from 8.1 μm to 8.5 μm, which is applicable when the substance to be measured is acetone.

[0015] The light source unit is two infrared light sources. The infrared light wavelength range emitted by the first infrared light source includes a first wavelength range and a second wavelength range, and the corresponding sensor units are a first sensing unit and a second sensing unit;

[0016] The infrared light wavelength range emitted by the second infrared light source includes a third wavelength range and a fourth wavelength range, and the corresponding sensor units are a third sensing unit and a fourth sensing unit; The structures of the third sensing unit and the fourth sensing unit are the same as those of the first sensing unit and the second sensing unit.

[0017] The first wavelength range is from 7.1 μm to 7.5 μm, and the second wavelength range is from 8.1 μm to 8.5 μm, which is applicable to the substance to be measured being acetone; The third wavelength range is from 3.8 μm to 4.0 μm, and the fourth wavelength range is from 4.2 μm to 4.4 μm, which is applicable to the substance to be measured being CO2.

[0018] The infrared light wavelength range emitted by the first infrared light source is from 7.0 μm to 8.6 μm, and the infrared light wavelength range emitted by the second infrared light source is from 3.7 μm to 4.5 μm.

[0019] The detection device further includes a display, and the display is electrically connected to the processor unit; The light source unit, the sensor unit, the processor unit, and the display are connected to a power source.

[0020] The detection device for the concentration of trace gases in exhaled breath according to the present invention utilizes the absorption characteristic of gas molecules of the substance to be measured for infrared light of a specific wavelength, and the absorption intensity is related to the gas concentration. The sensor unit of the detection device in this application adopts a dual-sensing unit to perform differential measurement on the gas and perform data processing through the processing unit, thereby reducing environmental interference and improving data reliability.

[0021] The light source unit of the detection device in this application adopts two infrared light sources to emit infrared light in different wavelength ranges, so that the gas molecules of the substance to be measured in exhaled breath have the absorption characteristic for infrared light of a specific wavelength, thereby distinguishing the substance to be measured and detecting the gas concentration of the substance to be measured, thereby improving the detection accuracy of trace gases.

[0022] The detection device for the concentration of trace gases in exhaled breath according to the present invention adopts two infrared light sources with different wavelength ranges and a sensor unit with two sets of dual-sensing units, so that the gas molecules of the substance to be measured in exhaled breath have the absorption characteristic for infrared light of a specific wavelength, perform differential measurement on the gas and perform data processing through the processing unit, thereby distinguishing the substance to be measured and detecting the gas concentration of the substance to be measured, and improving the detection accuracy of trace gases. Description of the Drawings

[0023] Figure 1This is a schematic structural diagram of a detection device for the concentration of trace gases in exhaled breath of the present invention.

[0024] In the figure: 1 light source unit, 2 optical cavity, 3 sensor unit, 31 first sensing unit, 32 second sensing unit, 4 processor unit, 5 gas inlet, 6 gas outlet, 7 display, 8 gas nozzle. Specific embodiments

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] A detection device for the concentration of trace gases in exhaled breath is used to detect the gas concentration value of the substance to be detected in the exhaled breath of the human body. Under the irradiation of an infrared light source, the gas to be detected absorbs light with a first absorption wavelength and a second absorption wavelength. By the differential absorption method, that is, by comparing the absorption characteristics at different wavelengths to detect the gas concentration, it can effectively reduce environmental interference and improve the detection accuracy.

[0027] See Figure 1 , a detection device for the concentration of trace gases in exhaled breath, includes a light source unit 1, an optical cavity 2, a sensor unit 3, a processor unit 4, and a display 7. The measurement light emitted by the light source unit 1 is projected into the optical cavity 2. A gas inlet 5 is opened at the end of the optical cavity 2 close to the light source unit 1. The gas inlet 5 is connected to the gas nozzle 8. The exhaled breath of the human body enters the optical cavity 2 through the gas nozzle 8 and the gas inlet 5. A gas outlet 6 is opened at the end of the optical cavity 2 close to the sensor unit 3. The sensor unit 3 measures the absorption spectrum of the measurement light transmitted through the exhaled breath in the optical cavity 2. The sensor unit 3 outputs and is electrically connected to the processor unit 4. The processor unit 4 is used for processing data, storing data, comparing data, and outputting data. The light source unit 1, the sensor unit 3, the processor unit 4, and the display 7 are connected to a power supply.

[0028] The processor unit 4 is electrically connected to the light source unit 1 and the display 7 to control the light source unit 1 to emit infrared rays and output data to the display 7 to display the gas concentration value.

[0029] The sensor unit 3 includes a first sensing unit 31 and a second sensing unit 32. The first sensing unit 31 includes a first filter and a first sensor. The first filter allows a first portion of the light with wavelengths in the first wavelength range for measuring the gas absorption spectrum in the optical cavity 2 to pass through. The first sensor is disposed downstream of the first filter, receives the first portion of the light passing through the first filter, and outputs a first detection signal indicating the first portion of the light in real time. The second sensing unit 32 includes a second filter and a second sensor. The second filter allows a second portion of the light with wavelengths in the second wavelength range for measuring the gas absorption spectrum in the optical cavity 2 to pass through. The second sensor is disposed downstream of the second filter, receives the second portion of the light passing through the second filter, and outputs a second detection signal indicating the second portion of the light in real time.

[0030] The processor unit 4 is electrically connected to the first sensor and the second sensor, obtains the first detection signal and the second detection signal, performs differential calculation to obtain the light intensity difference, and calculates the gas concentration using the differential light intensity according to existing technologies such as the absorption law (e.g., Beer-Lambert law), thereby obtaining the gas concentration of the substance to be measured present in the respiratory gas.

[0031] The respiratory gas exhaled by the human body generally contains carbon dioxide. For diabetic patients, the level of acetone in their blood will increase significantly. Understanding or measuring the acetone concentration in the exhaled breath can, to some extent, reflect the metabolic condition of diabetic patients. In the following embodiments, the measurement of acetone concentration and carbon dioxide concentration in the exhaled breath is mainly described.

[0032] Embodiment 1, A detection device for trace gas concentration in exhaled breath according to the present application. The light source unit 1 is an infrared light source. The wavelength range of the infrared light emitted by the infrared light source includes a first wavelength range and a second wavelength range. The first wavelength range is from 7.1 μm to 7.5 μm, and the second wavelength range is from 8.1 μm to 8.5 μm. The processor unit 4 controls the light source unit 1 to control the infrared light source to emit infrared light with a wavelength range from 7.0 μm to 8.6 μm.

[0033] The first sensing unit 31 includes a first filter and a first sensor. The first absorption wavelength detected by the first sensing unit 31 is 7.3 μm, which is located at the gas absorption peak (measurement wavelength). The second sensing unit 32 includes a second filter and a second sensor. The second absorption wavelength detected by the second sensing unit 32 is 8.3 μm, which is located at a wavelength with weak or no absorption (reference wavelength). That is, 7.3 μm is the measurement wavelength and 8.3 μm is the reference wavelength. By comparing the light intensity changes at these two wavelengths, the gas concentration can be accurately calculated to obtain the gas concentration of the substance to be measured as acetone.

[0034] Embodiment 2. A detection device for the concentration of trace gases in exhaled breath. The light source unit 1 is two infrared light sources, and the sensor unit 3 is two groups of sensing units. The infrared light wavelength range emitted by the first infrared light source includes a first wavelength range and a second wavelength range, and the corresponding sensor unit 3 is the first sensing unit 31 and the second sensing unit 32. As described in Embodiment 1, the gas concentration of the substance to be measured as acetone can be obtained.

[0035] The infrared light wavelength range emitted by the second infrared light source includes a third wavelength range and a fourth wavelength range, and the corresponding sensor unit 3 is the third sensing unit and the fourth sensing unit; the structures of the third sensing unit and the fourth sensing unit are the same as those of the first sensing unit 31 and the second sensing unit 32.

[0036] The processor unit 4 controls the light source unit 1 to control the infrared light wavelength range emitted by the second infrared light source to be from 3.7 μm to 4.5 μm. The third wavelength range is from 3.8 μm to 4.0 μm, and the fourth wavelength range is from 4.2 μm to 4.4 μm.

[0037] The third sensing unit includes a third filter and a third sensor. The third absorption wavelength detected by the third sensing unit is 3.9 μm, and this wavelength is in the wavelength range with weak or no absorption (reference wavelength). The fourth sensing unit includes a fourth filter and a fourth sensor. The fourth absorption wavelength detected by the fourth sensing unit is 4.3 μm, and this wavelength is at the gas absorption peak (measurement wavelength), that is: 4.3 μm is the measurement wavelength, 3.9 μm is the reference wavelength. By comparing the light intensity changes at these two wavelengths, the gas concentration can be accurately calculated, and the gas concentration of the substance to be measured as carbon dioxide can be obtained.

[0038] Similarly, according to the wavelength characteristics of the absorption spectrum of the substance to be measured for infrared light, the corresponding wavelength range can be selected, the corresponding sensing unit can be set, and the wavelength range of the infrared light source can be controlled to detect the gas concentration of the substance to be measured. For example, to detect the NH3 gas concentration in exhaled breath.

[0039] The detection device of the present invention is based on the absorption characteristics of the gas molecules of the substance to be measured in exhaled breath for infrared light of a specific wavelength. It uses infrared light sources with different wavelength ranges and a sensor unit with two groups or more than two groups of dual-sensing units to perform differential measurement on exhaled breath and perform data processing through a processing unit, so as to distinguish the substance to be measured and detect the gas concentration of the substance to be measured, improving the detection accuracy of trace gases.

[0040] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for detecting trace gas concentration in respiratory gas, characterized in that: The invention comprises a light source unit (1), an optical cavity (2), a sensor unit (3) and a processor unit (4); the measurement light emitted by the light source unit (1) is projected into the optical cavity (2); a gas inlet (5) is provided at the end of the optical cavity (2) close to the light source unit (1); the gas inlet (5) is connected to a gas nozzle (8); a gas outlet (6) is provided at the end of the optical cavity (2) close to the sensor unit (3); the sensor unit (3) measures the absorption spectrum of the measurement light transmitted through the respiratory gas in the optical cavity (2); the output of the sensor unit (3) is electrically connected to the processor unit (4); the processor unit (4) is electrically connected to the light source unit (1); the sensor unit (3) comprises a first sensing unit (31) and a second sensing unit (32); The first sensing unit (31) comprises a first optical filter and a first sensor, wherein the first optical filter allows a first portion of light having a wavelength within a first wavelength range of a gas measurement light absorption spectrum in the optical cavity to pass through; the first sensor is arranged downstream of the first optical filter, receives the first portion of light passing through the first optical filter, and outputs a first detection signal indicating the first portion of light in real time; The second sensing unit (32) comprises a second optical filter and a second sensor, wherein the second optical filter allows a second portion of light having a wavelength within a second wavelength range of the gas measurement light absorption spectrum in the optical cavity to pass through; the second sensor is arranged downstream of the second optical filter, receives the second portion of light passing through the second optical filter, and outputs a second detection signal indicating the second portion of light in real time; The processor unit (4) is electrically connected to the first sensor and the second sensor, obtains a first detection signal and a second detection signal, performs differential calculation to obtain a light intensity difference, and further obtains a gas concentration of a substance to be detected in the respiratory gas.

2. The device for detecting trace gas concentration in respiratory gas according to claim 1, characterized in that: The light source unit (1) is an infrared light source, and the infrared wavelength range emitted by the infrared light source includes a first wavelength range and a second wavelength range.

3. The device for detecting trace gas concentration in respiratory gas according to claim 2, characterized in that: The first wavelength range is 7.1 μm to 7.5 μm, and the second wavelength range is 8.1 μm to 8.5 μm, which is suitable for the substance to be tested being acetone.

4. The device for detecting trace gas concentration in respiratory gas according to claim 1, characterized in that: The light source unit (1) is two infrared light sources, the infrared wavelength range emitted by the first infrared light source includes a first wavelength range and a second wavelength range, and the corresponding sensor units (3) are a first sensing unit (31) and a second sensing unit (32); The infrared wavelength range emitted by the second infrared light source includes a third wavelength range and a fourth wavelength range, and the corresponding sensor units (3) are a third sensing unit and a fourth sensing unit; the structures of the third sensing unit and the fourth sensing unit are the same as those of the first sensing unit (31) and the second sensing unit (32).

5. The device for detecting trace gas concentration in respiratory gas according to claim 4, characterized in that: The first wavelength range is 7.1 μm to 7.5 μm, the second wavelength range is 8.1 μm to 8.5 μm, and is suitable for the substance to be tested being acetone; the third wavelength range is 3.8 μm to 4.0 μm, and the fourth wavelength range is 4.2 μm to 4.4 μm, and is suitable for the substance to be tested being CO2.

6. The device for detecting trace gas concentration in respiratory gas according to claim 4 or 5, characterized in that: The infrared light emitted by the first infrared light source has a wavelength range of 7.0 μm to 8.6 μm, and the infrared light emitted by the second infrared light source has a wavelength range of 3.7 μm to 4.5 μm.

7. The device for detecting trace gas concentration in respiratory gas according to claim 1, characterized in that: The detection device further comprises a display (7), and the display (7) is electrically connected to the processor unit (4); the light source unit (1), the sensor unit (3), the processor unit (4) and the display (7) are connected to a power supply.

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