Gas concentration detection device and measurement method based on narrow-band light source of Fourier spectrometer

Abstract

The present invention discloses a gas concentration detection device and a measurement method based on a narrow-band light source of a Fourier spectrometer. The present invention is to solve the problems of contact with gas, low test sensitivity, and single test means in the existing gas concentration test method. The detection device is a narrow-band infrared light emitted by a narrow-band radiation light source entering the Fourier spectrometer, and the gas chamber is placed in the sample chamber of the Fourier spectrometer, and finally the spectrum is detected by the detector. The narrow-band radiation light source emits narrow-band infrared light by heating a narrow-band radiator, or a narrow-band infrared light source is obtained by a broadband infrared light source through a narrow-band filter. The narrow-band radiation light source is incident on the Fourier spectrometer through an external light source port. The gas to be tested is added to the gas chamber, and the concentration of the filled gas can be controlled. The gas concentration detection method has the advantages of high sensitivity and contactless detection.

Description

Technical Field

[0001] The invention relates to the field of gas sensors, to an infrared gas sensing detection device and a detection method thereof, and in particular to a non-contact, high-sensitivity gas concentration detection. Background Art

[0002] Gas concentration detection plays a vital role in people's lives and industrial production. Commonly used gas concentration detection methods include semiconductor sensors, catalytic combustion sensors, electrochemical sensors, etc., but these test methods require the instrument to be tested to contact the sensor or even undergo a chemical reaction to detect the gas concentration, which is bound to cause the risk of leakage of the gas to be tested, and at the same time, the sensor life is not long. The emergence of infrared sensors solves the problem of contact between the gas to be tested and the sensor. The concentration of the gas can be further calculated by measuring the attenuation of the light intensity passing through the gas to be tested. However, the light source used in the existing detector of this method is usually a broadband light source. Since the extinction coefficient of the gas is usually small and the absorption peak bandwidth of the gas molecules is narrow, the sensitivity of the measurement of this method is relatively small. Therefore, the development of non-contact high-sensitivity gas detection devices has become a research hotspot in the field of gas detection. In view of the problems existing in the above-mentioned traditional gas detection, the present invention discloses a gas concentration detection device based on a narrow-band radiation source of a Fourier instrument and a measurement method thereof. The device has the characteristics of non-contact and high sensitivity. Summary of the invention

[0003] The present invention discloses a gas concentration detection device and a measurement method based on a narrow-band light source of a Fourier spectrometer. The structural schematic diagram is shown in FIG. Figure 1 As shown, it includes a narrowband radiation source 1, a Fourier spectrometer 2, a gas chamber 3, and a detector 4.

[0004] The purpose of the present invention is to provide a non-contact high-sensitivity gas concentration detection device and a measurement method thereof, which makes up for the shortcomings of chemical methods such as short detection life, high price and easy damage, as well as the low sensitivity of infrared measurement methods, and realizes non-contact high-sensitivity gas concentration detection.

[0005] A first object of the present invention is to provide a non-contact infrared sensor for gas concentration detection.

[0006] The second purpose of the present invention is to detect gas concentration with high sensitivity, which is more than 10 times higher than the broadband infrared type.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] 1. A gas concentration detection device based on a narrow-band light source of a Fourier spectrometer, comprising: a narrow-band radiation source 1, a Fourier spectrometer 2, a gas chamber 3, and a detector 4.

[0009] 2. The gas concentration detection device based on a narrowband light source of a Fourier spectrometer is characterized in that: a) The narrowband radiation light source emits narrowband light by heating a narrowband radiator, or a narrowband light source is obtained by a broadband light source passing through a narrowband filter; b) The gas to be measured is added to the gas chamber, and the gas chamber is sealed with a fixed volume; c) The Fourier spectrometer can use an external light source.

[0010] 3. The light source of the gas concentration detection device belongs to a narrowband, and the narrowband peak is the same as the absorption peak of the gas to be measured.

[0011] 4. The gas chamber of the gas concentration detection device is sealed, and the volume V of the gas chamber is fixed.

[0012] 5. The gas concentration detection device and its measurement method include the following steps:

[0013] Step 1: The emission peak of the light source is the same as the absorption peak of the gas to be measured;

[0014] Step 2: Gas concentration calibration. The gas chamber is filled with air, and the transmission spectrum is detected by a Fourier spectrometer. The light intensity at the emission peak position of the light source is I0. Gas concentration C1 is introduced, and the transmission spectrum is measured. The light intensity at the emission peak position is I1... I n , and n is usually taken until the intensity of the emission peak no longer decreases;

[0015] Step 3: Taking the gas concentration C as the x-axis and the sensitivity S: S = (I0 - I n ) / I0 as the y-axis, draw the corresponding graph of the gas concentration.

[0016] Step 4: Measure the concentration of the gas. The gas chamber is filled with air, and the transmission spectrum is detected by a Fourier spectrometer. The light intensity at the emission peak position of the light source is I0. A volume V x of the gas to be measured V x << V is filled, and the light intensity at the emission peak position is measured as I x , (I0 - I n ) / I0 is used to find the corresponding gas concentration C in the concentration graph a , and further calculate the concentration C of the filled gas x = C a (V / V x ).

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The gas concentration detection device of the present invention makes up for the deficiencies of short detection life, high price, and easy damage of chemical methods, and is an infrared sensing measurement.

[0019] 2. The gas concentration detection device of the present invention makes up for the problem of low sensitivity of the infrared measurement method, realizes non-contact high-sensitivity gas concentration detection, and is more than 10 times more sensitive than the broadband infrared type. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a gas concentration detection device based on a narrow-band infrared radiation source of a Fourier spectrometer;

[0021] Reference numerals:

[0022] 1- narrowband radiation source, 2- Fourier spectrometer, 3- gas chamber, 4- detector.

[0023] Figure 2 The formaldehyde sensitivity of the gas concentration detection device tested by the Fourier spectrometer narrow-band infrared radiation source and the formaldehyde sensitivity tested by using a black body as a light source; DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0025] like Figure 1 As shown, a schematic diagram of a gas concentration detection device based on a narrow-band infrared radiation source of a Fourier spectrometer:

[0026] The invention comprises: a narrowband radiation source 1, a Fourier spectrometer 2, a gas chamber 3, and a detector 4. The invention is characterized in that: a) the narrowband radiation source emits narrowband light by heating a narrowband radiator, or obtains a narrowband light source by a broadband light source through a narrowband filter; b) the gas to be tested is added into the gas chamber, which is sealed and has a fixed volume; c) the Fourier spectrometer can use an external light source.

[0027] The gas concentration detection device test includes the following steps:

[0028] Step 1: The emission peak of the light source is the same as the absorption peak of the gas being measured;

[0029] Step 2: Calibrate the gas concentration. Fill the gas chamber with air and detect the transmission spectrum with a Fourier spectrometer. The peak light intensity of the light source is I0. Pass the gas concentration C1 and measure the transmission spectrum. The peak light intensity is I1…I n , n is usually taken until the emission peak intensity no longer decreases;

[0030] Step 3: With gas concentration C as x-axis, sensitivity S: S = (I0-I n ) / I0 is used as the y-axis to draw a corresponding graph of gas concentration.

[0031] Step 4: Measure the concentration of the gas. Fill the gas chamber with air and detect the transmission spectrum using a Fourier spectrometer. The peak light intensity of the light source is I0. Fill V xAn amount of the gas V to be measured x <<V, measure the light intensity I at the peak position of the emission x , (I0 - I n ) / I0 to find the corresponding gas concentration C in the concentration graph a , further calculate the concentration C of the gas filled x = C a (V / V x ).

[0032] Example 1

[0033] A gas concentration detection device and measurement method based on a narrowband light source of a Fourier spectrometer include the following steps:

[0034] Step 1: Select a suitable light source with an emission peak of 3.58um. The absorption peak of formaldehyde molecules is also 3.58um;

[0035] Step 2: Calibrate the gas concentration. Fill the gas chamber with air, detect the transmission spectrum through the Fourier spectrometer. The light intensity at the peak position of the light source emission is I0. Introduce a gas concentration C1, measure the transmission spectrum, and the light intensity at the peak position of the emission is I1... until the emission peak intensity no longer decreases;

[0036] Step 3: Take the gas concentration C as the x-axis and the sensitivity S: S = (I0 - I n ) / I0 as the y-axis to plot the corresponding graph of gas concentration, as shown in Figure 2 the black dotted line graph.

[0037] Step 4: Repeat Step 2 and Step 3. Use the black body as the light source and plot the corresponding relationship between the black body sensitivity and the gas concentration, as shown in Figure 2 the black triangular line graph.

[0038] Step 5: Measure the concentration of the gas. Fill the gas chamber with air, detect the transmission spectrum through the Fourier spectrometer. The light intensity at the peak position of the light source emission is I0. Fill in an x amount of the gas V to be measured x <<V, measure the light intensity I at the peak position of the emission x , (I0 - I n ) / I0 to find the corresponding gas concentration C in the concentration graph a , further calculate the concentration C of the gas filled x = C a (V / V x ).

[0039] In addition, it should be noted that the specific embodiments described in this specification may be named differently, and the above contents described in this specification are merely examples of the structure of the present invention. Any small or simple changes made based on the structure, features and principles of the present invention are included in the protection scope of the present invention. Those skilled in the art of the present invention may make various modifications or supplements to the specific examples described or adopt similar methods, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for measuring gas concentration based on a narrow-band light source of a Fourier spectrometer, the method using a detection device, the detection device comprising: A narrowband radiation source (1), a Fourier spectrometer (2), a gas chamber (3), and a detector (4), characterized in that: The narrowband radiation light source (1) emits narrowband light by heating a narrowband radiator, or obtains a narrowband light source by passing a broadband light source through a narrowband filter; the gas to be tested is added to the gas chamber (3), which is sealed and has a fixed volume; the Fourier spectrometer (2) has an available external light source port; The measurement method includes the following steps: Step 1: The emission peak of the light source is the same as the absorption peak of the gas being measured; Step 2: Calibrate the gas concentration. Fill the gas chamber with air and detect the transmission spectrum with a Fourier spectrometer. The peak light intensity of the light source is I0. Pass the gas concentration C1 and measure the transmission spectrum. The peak light intensity is I1…I n , n is usually taken until the emission peak intensity no longer decreases; Step 3: With gas concentration C as x-axis, sensitivity S: S=(I0-I n ) / I0 is the y-axis to draw the corresponding graph of gas concentration; Step 4: Measure the concentration of the gas. Fill the gas chamber with air, detect the transmission spectrum through a Fourier spectrometer. The light intensity at the emission peak of the light source is I0. Fill in the measured gas V x quantity of the gas to be measured V x <<V, measure the light intensity I at the emission peak x , (I0 - I n ) / I0 to find the corresponding gas concentration C in the concentration graph a , further calculate the concentration C of the filled gas x = C a (V / V x ).

2. The method for measuring gas concentration based on a narrow-band light source of a Fourier spectrometer according to claim 1, characterized in that: The bandwidth of the narrow-band radiation light source (1) is consistent with the absorption peak of the gas to be measured.

3. The method for measuring gas concentration based on a narrow-band light source of a Fourier spectrometer according to claim 1, characterized in that: The gas chamber (3) is airtight, and the volume of the gas chamber is V.

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