Infrared gas sniffing detector

Abstract

The invention relates to the technical field of gas detection, in particular to an infrared gas sniffing detector. The infrared gas sniffing detector comprises a gas pump used for sucking gas to be detected into a gas absorption chamber under first power or second power; the infrared detection unit comprises a gas absorption chamber, a detector and an infrared light source; the control unit is connected with the air pump and the detector, and is used for controlling the working power of the air pump and controlling the working power of the air pump according to the infrared light intensity detected by the detector when the air pump is under the first power and the second power and the gas flow rate of the gas to be detected when the air pump is under the first power and the second power; and determining the concentration of the gas to be detected when the gas pump is under the second power and the first power. The infrared gas sniffing detector provided by the invention can accurately detect the concentration of the gas and accurately detect the leakage point and the leakage rate while reference gas is not needed.

Description

Technical Field

[0001] This application relates to the technical field of gas detection, and particularly to an infrared gas sniffer detector. Background Art

[0002] A gas sniffer is a device used to detect and analyze gas leaks, and is widely used in industries, environmental protection, safety and other fields. It can detect a variety of gases, including but not limited to flammable gases, toxic gases, volatile organic compounds (VOCs), etc.

[0003] Among gas sniffers, an infrared gas sniffer that uses non-dispersive infrared technology (NDIR) for gas detection is widely used in various gas detection scenarios due to its advantages such as not being in direct contact with the gas and having a long service life.

[0004] In the existing infrared gas sniffer detectors, a reference gas is often required to assist in the concentration of the gas to be measured. This method not only makes the structure of the infrared gas sniffer complex and increases the cost, but also the reference gas used is easily contaminated by the gas to be measured, resulting in low detection accuracy. Summary of the Invention

[0005] In order to solve the deficiencies of the existing technology, the purpose of this application is to provide an infrared gas sniffer detector that can accurately detect the concentration of gas without using a reference gas.

[0006] To achieve the above purpose, this application provides an infrared gas sniffer detector, including:

[0007] An air pump for sucking the gas to be measured into the gas absorption chamber at a first power or a second power, where the first power is different from the second power, the second power is not less than 30% of the full power of the air pump, and the first power is greater than the second power;

[0008] An infrared detection unit, including a gas absorption chamber, a detector and an infrared light source; the infrared light source is arranged at one end of the gas absorption chamber for intake of gas; the detector is arranged at one end of the gas absorption chamber for exhaust of gas, and is used to detect the intensity of the infrared light received;

[0009] A control unit, connected to the air pump and the detector, for controlling the power of the air pump to work, and determining the concentration of the gas to be measured when the air pump is at the second power and the first power according to the intensity of the infrared light detected by the detector when the air pump is at the first power and the second power, and the gas flow rates of the gas to be measured when the air pump is at the first power and the second power.

[0010] Further, the specific steps for determining the concentration of the gas to be measured when the air pump is at the second power and the first power are as follows:

[0011]

[0012] Wherein, C2 is the concentration of the gas to be measured when the air pump is at the second power, C1 is the concentration of the gas to be measured when the air pump is at the first power, K is the gas absorption coefficient of the gas to be measured, l is the thickness of the gas to be measured in the gas absorption chamber, and I t1 is the infrared light intensity detected by the detector when the air pump is at the first power, and I t2 is the infrared light intensity detected by the detector when the air pump is at the second power.

[0013] Further, the gas flow rates of the gas to be measured when the air pump is at the first power and the second power are pre-detected by a flow meter respectively when the air pump is at the first power and the second power before leaving the factory, and are configured in the control unit.

[0014] Further, it further includes:

[0015] A flow meter, connected to the control unit, is arranged in the gas passage for detecting the gas flow rate of the gas to be measured when the air pump is at the first power or the second power, and outputting it to the control unit.

[0016] Further, the infrared detection unit further includes a filter, and the filter is arranged at any end of the gas absorption chamber.

[0017] Further, it further includes:

[0018] A feedback unit, connected to the control unit, for feeding back the detection result to the user.

[0019] Further, the feedback unit includes any one of a buzzer, an indicator light and a display screen.

[0020] Further, the first power is 100% of the full power of the air pump, and the second power is 40% of the full power of the air pump.

[0021] To achieve the above object, the present application further provides a refrigerant leakage detection method, which is applied to the infrared gas sniffer as described above. The method includes:

[0022] Controlling the air pump to be at the first power, and the detector detects the infrared light intensity at the first power;

[0023] Controlling the air pump to be at the second power, and the detector detects the infrared light intensity at the second power;

[0024] According to the gas flow rates of the air pump at the first power and the second power detected in real time or measured in advance, and the infrared light intensities of the air pump at the first power and the second power, the gas concentration of the gas to be measured at the first power and / or the second power of the air pump is calculated.

[0025] The infrared gas sniffing detector of the present application has a simple structure and does not require a reference gas. It can complete the concentration detection of the gas to be measured only with a single light source and a single detector. The structure is simple, easy to manufacture and has low cost.

[0026] The infrared gas sniffing detector of the present application detects the light intensity of the gas to be measured at different powers of the air pump, and then detects the concentration of the gas to be measured, with high detection accuracy.

[0027] Other features and advantages of the present application will be described in the subsequent specification, and in part will be obvious from the specification, or will be understood by implementing the present application. Description of the Drawings

[0028] The drawings are used to provide a further understanding of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application. In the drawings:

[0029] Figure 1 is the principle block diagram of the infrared gas sniffing detector according to Embodiment 1 of the present application;

[0030] Figure 2 is the structural schematic diagram of the infrared gas sniffing detector according to Embodiment 1 of the present application;

[0031] Figure 3 is the detection signal waveform diagram detected by the detector when the air pump switches power in an air environment;

[0032] Figure 4 is the detection signal waveform diagram detected by the detector when the air pump switches power in a leakage environment;

[0033] Figure 5 is the detection signal waveform diagram detected by the detector when the air pump switches power in another leakage environment;

[0034] Figure 6 is the principle block diagram of the infrared gas sniffing detector according to Embodiment 2 of the present application

[0035] Figure 7 is the structural schematic diagram of the infrared gas sniffing detector according to Embodiment 2 of the present application;

[0036] Description of the Drawings: 10 - Infrared gas sniffing detector, 11 - Gas inlet, 12 - Gas outlet, 13 - Infrared detection unit, 20 - Filter, 22 - Infrared light source, 23 - Filter, 24 - Gas absorption chamber, 25 - Detector, 26 - Air pump, 30 - First gas conduit, 32 - Second gas conduit, 33 - Third gas conduit, 40 - Flowmeter, 100 - Control unit, 200 - Feedback unit. Detailed Implementation Manner

[0037] Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not used to limit the protection scope of the present application.

[0038] It should be understood that the various steps recited in the method embodiments of the present application can be executed in a different order and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present application is not limited in this regard.

[0039] As used herein, the term "including" and its variations are open-ended, i.e., "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0040] It should be noted that the modifications of "one" and "multiple" mentioned in the present application are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly specified in the context, it should be understood as "one or more". "Multiple" should be understood as two or more.

[0041] Next, embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0042] Embodiment 1

[0043] One embodiment of the present application provides an infrared gas sniffing detector that improves the detection accuracy of gas while not requiring a reference gas. Next, reference will be made to Figures 1-5 describe the infrared gas sniffing detector of the present application in detail, including:

[0044] An air pump 26 is used to suck the gas to be measured into the gas absorption chamber 24 at a first power or a second power. The first power is different from the second power, the second power is not less than 30% of the full power of the air pump, and the first power is greater than the second power.

[0045] An infrared detection unit 13 includes a gas absorption chamber 24, a detector 25 and an infrared light source 22. The infrared light source 22 is arranged at one end of the gas absorption chamber 24 for intake of gas. The detector 25 is arranged at one end of the gas absorption chamber 24 for exhaust of gas, and is used to detect the intensity of the received infrared light.

[0046] A control unit 100 is connected to the air pump 26 and the detector 25, and is used to control the power of the air pump during operation, and determine the concentration of the gas to be measured when the air pump 26 is at the second power and the first power according to the infrared light intensities detected by the detector 25 when the air pump 26 is at the first power and the second power respectively, and the gas flow rates of the gas to be measured when the air pump 26 is at the first power and the second power.

[0047] In this embodiment, the gas absorption chamber 24 is connected to the gas inlet 11 through a first gas conduit 30, the gas absorption chamber 24 is connected to the air pump 26 through a second gas conduit 32, and the air pump 26 is connected to the gas outlet 12 through a third gas conduit 33.

[0048] In this embodiment, the specific steps for determining the concentration of the gas to be measured when the air pump 26 is at the second power and the first power adopt the following formula:

[0049]

[0050] Wherein, C2 is the concentration of the gas to be measured when the air pump 26 is at the second power, C1 is the concentration of the gas to be measured when the air pump 26 is at the first power, K is the gas absorption coefficient of the gas to be measured, l is the thickness of the gas to be measured in the gas absorption chamber, I t1 is the infrared light intensity detected by the detector 25 when the air pump is at the first power, and I t2 is the infrared light intensity detected by the detector 25 when the air pump 26 is at the second power.

[0051] It should be noted that the principle for determining the concentration of the gas to be measured when the air pump is at the second power and the first power is as follows:

[0052] Since the leakage rate of the gas to be detected at a detection point is constant within a certain period of time, which is set as Q leak , assuming that the total gas flow rate sucked by the air pump 26 when working at the first power is known as Q1, and the total gas flow rate sucked by the air pump 26 when working at the second power is known as Q2. Then, the concentrations of the gas to be measured sucked into the gas absorption chamber under the two powers are:

[0053]

[0054] Among them, c1 is the concentration of the gas to be measured when the air pump 26 is at the first power, and C2 is the concentration of the gas to be measured when the air pump 26 is at the second power.

[0055] Thus, it can be obtained that:

[0056]

[0057] Also, because the light intensities detected by the detector 25 at the two concentrations can be obtained respectively according to the Beer-Lambert law:

[0058]

[0059] Among them: I0 is the incident light intensity, K is the gas absorption coefficient of the gas to be measured, l is the thickness of the gas to be measured in the gas absorption chamber, I t1 is the infrared light intensity detected by the detector when the air pump is at the first power, I t2 is the infrared light intensity detected by the detector when the air pump is at the second power.

[0060] Thus, by substituting respectively, it can be obtained that:

[0061]

[0062] In this embodiment, the gas flow rates Q1 and Q2 of the gas to be measured when the air pump is at the first power and the second power are pre-detected respectively by using a flow meter before leaving the factory when the air pump is at the first power and the second power, and are configured in the control unit 100.

[0063] It should be noted that the power of the air pump is controlled by controlling the driving PWM of the air pump.

[0064] It should be noted that the gas flow rates Q1 and Q2 are positively correlated with the working power of the air pump 26, that is, the greater the power, the greater the gas flow rate. In actual use, the ratio of the gas flow rates Q1 and Q2 can also be directly calculated according to the magnitude of the driving PWM value of the air pump 26.

[0065] It can be understood that the specific parameters and ratios of the first power and the second power will be adaptively adjusted according to the actual gas path used, the power of the air pump, and the gas to be measured, etc.

[0066] It should be noted that when the difference between the first power and the second power is smaller, the measurement accuracy will be lower. When the difference between the first power and the second power is very small, to achieve accurate measurement, an amplifier circuit can also be used for assistance.

[0067] In addition, since the air pump cannot start when its power is lower than a certain level, which causes the detection to be unable to proceed. Through testing and verification, it is found that the power of the air pump should be at least more than 30% of the full power to ensure the normal progress of the detection.

[0068] In this embodiment, the first power is 100% of the full power of the air pump, and the second power is 40% of the full power of the air pump. In this way, the detection accuracy is the highest.

[0069] In this embodiment, the infrared detection unit 13 further includes a filter 23, which is disposed at either end of the gas absorption chamber 24, that is, it can be disposed at the detector 25 end to filter the infrared light band entering the detector 25, or it can also be disposed at both ends of the infrared light source 22 and the detector 25.

[0070] In this embodiment, it further includes:

[0071] A feedback unit 200, connected to the control unit 100, for feeding back the detection result to the user.

[0072] It should be noted that the detection result can be the concentration of the gas to be measured when the air pump 26 is at the second power, or the concentration when at the first power, or it can include both the concentration when the air pump 26 is at the second power and the concentration when at the first power.

[0073] In some other embodiments, the detection result can also include the signal values detected at the two powers.

[0074] In this embodiment, the feedback unit 200 includes any one of a buzzer, an indicator light, and a display screen.

[0075] In this embodiment, the detector 25 includes any one of a pyroelectric sensor and a thermopile sensor.

[0076] Exemplarily, when using the infrared gas sniffer detector for detection in different environments, the signal change of the detector 25 is referred to Figures 3-5 , where Pwm = 100% indicates that the air pump 26 operates at full power, and Pwm = 60% indicates that the air pump 26 operates at 60% power. The abscissa is time, and the ordinate is the signal detected by the detector 25. As Figure 3 shown, in an air environment, when the air pump 26 operates at full power, a positive peak appears in the detection signal, with a peak value of about 50. When the air pump 26 operates at 60% power, a negative peak appears in the detection signal, with a peak value of about 50; as Figure 4As shown, the gas inlet is placed at the gas leakage point of the gas to be measured with a leakage rate of 5 g per year. When the air pump 26 operates at full power, a positive peak and a negative peak appear. The peak value of the positive peak is about 50, and the peak value of the negative peak is about 100. When the air pump 26 operates at 60% power, a negative peak appears, and the peak value is about 50; as Figure 5 As shown, the gas inlet is placed at the gas leakage point of the gas to be measured with a leakage rate of 50 g per year. When the air pump 26 operates at full power, a positive peak and a negative peak appear. The peak value of the positive peak is about 50, and the peak value of the negative peak is about 450. When the air pump 26 operates at 60% power, a negative peak appears, and the peak value is about 50.

[0077] It can be understood that when using the infrared gas sniffer detector for detection, by changing the measurement position and observing the detection results of the infrared gas sniffer detector, the leakage point position can be determined.

[0078] Embodiment 2

[0079] An embodiment of the present application provides an infrared gas sniffer detector, which improves the detection accuracy of the gas while not requiring a reference gas. The following will refer to Figures 6-7 to describe the infrared gas sniffer detector of the present application in detail. As Figures 6-7 shown, the difference between the infrared gas sniffer detector of Embodiment 2 of the present application and that of Embodiment 1 is as follows:

[0080] It further includes:

[0081] A flow meter 40, connected to the control unit 100, is arranged in the gas passage for detecting the gas flow rate of the gas to be measured when the air pump 26 is at the first power or the second power, and outputting it to the control unit 100.

[0082] In this embodiment, the flow meter 40 is arranged on the gas passage where the first gas conduit 30 is located.

[0083] In some other embodiments, the flow meter 40 can also be arranged on the second gas conduit 32.

[0084] In this embodiment, when using the following calculation formula for gas concentration:

[0085]

[0086] wherein, the gas flow rate Q2 and the gas flow rate Q1 are obtained by real-time detection of the flow meter, and the detection effect is more accurate.

[0087] The above description is only partial embodiments of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of disclosure involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present application.

[0088] In addition, although the operations are depicted in a particular order, this should not be construed as requiring that the operations be performed in the particular order shown or in sequential order. In certain environments, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the present application. Certain features described in the context of separate embodiments may also be implemented combinatorially in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments.

[0089] Although the subject matter has been described in language specific to structural features and / or methodological logical acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. On the contrary, the specific features and acts described above are merely example forms for implementing the claims.

Claims

1. An infrared gas sniffing detector, characterized in that, Comprising: An air pump for sucking a gas to be measured into a gas absorption chamber at a first power or a second power, wherein the second power is not less than 30% of the full power of the air pump, and the first power is greater than the second power; An infrared detection unit, including a gas absorption chamber, a detector, and an infrared light source; the infrared light source is arranged at one end of the gas absorption chamber for intake of gas; the detector is arranged at one end of the gas absorption chamber for exhaust of gas, and is used for detecting the intensity of the received infrared light; A control unit, connected to the air pump and the detector, for controlling the power of the air pump to work, and determining the concentrations of the gas to be measured when the air pump is at the second power and the first power according to the infrared light intensities detected by the detector when the air pump is at the first power and the second power respectively, and the gas flow rates of the gas to be measured when the air pump is at the first power and the second power.

2. The infrared gas sniffing detector according to claim 1, characterized in that, The specific steps for determining the concentrations of the gas to be measured when the air pump is at the second power and the first power adopt the following formula: Among them, C2 is the concentration of the gas to be measured when the air pump is at the second power, C1 is the concentration of the gas to be measured when the air pump is at the first power, K is the gas absorption coefficient of the gas to be measured, l is the thickness of the gas to be measured in the gas absorption chamber, I t1 is the infrared light intensity detected by the detector when the air pump is at the first power, I t2 is the infrared light intensity detected by the detector when the air pump is at the second power.

3. The infrared gas sniffing detector according to claim 1, characterized in that, The gas flow rates of the gas to be measured when the air pump is at the first power and the second power are pre-detected respectively by a flowmeter before leaving the factory when the air pump is at the first power and the second power, and are configured in the control unit.

4. The infrared gas sniffer detector according to claim 1, characterized in that, Further comprising: A flowmeter, connected to the control unit, arranged in the gas path, for detecting the gas flow rate of the gas to be measured when the air pump is at the first power or the second power, and outputting the detected result to the control unit.

5. The infrared gas sniffing detector according to claim 1, characterized in that, The detector includes any one of a pyroelectric sensor and a thermopile sensor.

6. The infrared gas sniffing detector according to claim 1, characterized in that, The infrared detection unit further includes a filter, and the filter is arranged at any one end of the gas absorption chamber.

7. The infrared gas sniffer detector according to claim 6, characterized in that, Further comprising: A feedback unit, connected to the control unit, for feeding back the detection result to the user.

8. The infrared gas sniffer detector according to claim 7, characterized in that, The feedback unit includes any one of a buzzer, an indicator light, and a display screen.

9. The infrared gas sniffing detector according to claim 1, characterized in that, The first power is 100% of the full power of the air pump, and the second power is 40% of the full power of the air pump.

10. A refrigerant leakage detection method, applied to the infrared gas sniffer detector according to any one of claims 1-9, characterized in that, The method includes: Controlling the air pump to be at the first power, and the detector detects the infrared light intensity at the first power; Controlling the air pump to be at the second power, and the detector detects the infrared light intensity at the second power; Calculating the gas concentration of the gas to be measured when the air pump is at the first power and / or the second power according to the gas flow rates of the air pump at the first power and the second power detected in real time or pre-determined, and the infrared light intensities at the first power and the second power of the air pump.

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