Constant current fluorescence measurement system in micro-negative pressure state and measurement method

Abstract

The application provides a constant current fluorescence measurement system and a measurement method in a micro-negative pressure state, and belongs to the technical field of gas measurement. The system comprises a first gas path conversion mechanism, an interference component removal device, a gas form conversion enrichment device and a fluorescence measurement device. The first gas path conversion mechanism is connected with a gas pipeline and an inert gas source. The interference component removal device is connected with the first gas path conversion mechanism. The gas form conversion enrichment device is connected with the first gas path conversion mechanism. The fluorescence measurement device is connected with the interference component removal device and the gas form conversion enrichment device. The fluorescence measurement device is used for measuring the concentration of the gas. The system further comprises a flow limiting device, which is connected with the second gas path conversion mechanism and the fluorescence measurement device. The flow limiting device is connected with an exhaust mechanism. The flow limiting device and the exhaust mechanism cooperate to stabilize the gas flow of the fluorescence measurement device and make the fluorescence measurement device in a negative pressure state. The application can keep the gas stable, improve the measurement precision and sensitivity, and has a wide application range.

Description

Technical Field

[0001] This invention relates to the field of gas measurement technology, and more specifically to a constant current fluorescence measurement system under a slight negative pressure state and a measurement method based on the constant current fluorescence measurement system under a slight negative pressure state. Background Technology

[0002] Currently, the technology for measuring gases using fluorescence measurement is developing rapidly. The specific process is as follows: the gas to be measured enters the measurement chamber and is excited by light emitted by the optical system, emitting fluorescence. The acquisition system acquires and processes the emitted fluorescence signal, and a linear concentration relationship is established through photoelectric conversion. In addition, most fluorescent gas component measurement devices use positive pressure pneumatic transmission to transport the sample gas. This requires an external pressure source to provide gas pressure (such as a gas compressor or gas cylinder). A flow control module limits the flow rate to around 1L~1.5L to deliver the sample gas to the measurement system. During the measurement process, the pressure in the measurement chamber is greater than 760mmHg, and the measurement chamber is in a slightly positive or positive pressure measurement state.

[0003] However, when the measurement system is under positive pressure to measure the trace concentration of a gas, problems such as changes in the absorption cross-section of the gas component being measured and distortion of the standard concentration measurement may occur. At the same time, the zero-point background of the positive pressure measurement system fluctuates greatly, and the baseline background also rises, making it impossible for the measurement system to accurately measure the concentration of trace or ultra-trace gas. Furthermore, because positive pressure pushes the gas in the gas path, the pressure is unstable when the system switches sample gases, and the consistency of gas pulses deteriorates during periodic mode switching measurements. In addition, positive pressure gas measurement systems have certain limitations and are not suitable for special gases, such as high-viscosity gases, flammable gases, toxic gases, and other harmful gases. If the system leaks or malfunctions, gas leakage may cause harm to personnel. Summary of the Invention

[0004] The purpose of this invention is to provide a constant current fluorescence measurement system and method under slight negative pressure to solve the following problems: when the measurement system is under positive pressure for measuring trace gas concentrations, the absorption cross-section of the measured gas component changes, and the standard concentration measurement is distorted; at the same time, the zero-point background of the positive pressure measurement system fluctuates greatly, and the baseline background also rises, making it impossible for the measurement system to accurately measure the concentration of trace or ultra-trace gas. Furthermore, because positive pressure pushes the gas in the gas path, the pressure is unstable when the system switches sample gases, and the consistency of gas pulses deteriorates during periodic mode switching measurements; in addition, the positive pressure gas measurement system has certain limitations and is not suitable for special gases, such as high-viscosity gases, flammable gases, toxic gases, and other harmful gases. If the system leaks or malfunctions, gas leakage may cause harm to personnel.

[0005] To achieve the above objectives, embodiments of the present invention provide a constant current fluorescence measurement system under a slightly negative pressure state, the system comprising:

[0006] The first gas path conversion mechanism has an air inlet connected to the gas delivery pipeline to be tested and an inert gas source.

[0007] An interfering component removal device, wherein the air inlet of the interfering component removal device is connected to the air outlet of the first gas path conversion mechanism, and is used to remove interfering components in the gas to be tested.

[0008] A gas state conversion and enrichment device, wherein the inlet of the interfering component removal device is connected to the outlet of the first gas path conversion mechanism, and is used to perform gas state conversion and gas enrichment on the gas to be tested.

[0009] A fluorescence measuring device, wherein the air inlet of the fluorescence measuring device is connected to the air outlet of the interfering component removal device and the air outlet of the gas state conversion and enrichment device through a second gas path conversion mechanism, and is used to measure the concentration of the gas to be measured.

[0010] A flow limiting device is provided, wherein the air inlet of the flow limiting device is connected to the air outlet of the second air path conversion mechanism and the air outlet of the fluorescence measuring device, and the air outlet of the flow limiting device is connected to the exhaust mechanism. The flow limiting device and the exhaust mechanism cooperate with each other to stabilize the air inlet flow of the fluorescence measuring device and to keep the fluorescence measuring device under negative pressure.

[0011] Optionally, the first gas path switching mechanism includes:

[0012] First three-way connector and first three-way valve;

[0013] The inlet of the first three-way connector is connected to the gas delivery pipeline to be tested, the first outlet of the first three-way connector is connected to the first inlet of the first three-way valve, and the second outlet is connected to the inlet of the interfering component removal device.

[0014] The second port of the first three-way valve is connected to the inert gas source, and the outlet of the first three-way valve is connected to the inlet of the gas state conversion and enrichment device.

[0015] Optionally, the second gas path switching mechanism includes:

[0016] Second three-way valve and third three-way valve;

[0017] The first air inlet of the second three-way valve is connected to the air outlet of the interfering component removal device, the second air inlet of the second three-way valve is connected to the first air outlet of the third three-way valve, and the air outlet of the second three-way valve is connected to the air inlet of the fluorescence measuring device.

[0018] The inlet of the third three-way valve is connected to the outlet of the gas state conversion and enrichment device, and the second outlet of the third three-way valve is connected to the inlet of the flow limiting device.

[0019] Optionally, the flow limiting device is connected to the air inlet of the exhaust mechanism via a second tee connector, and the flow limiting device includes:

[0020] The first flow limiting device has its inlet connected to the outlet of the second air path conversion mechanism, and its outlet is connected to the first inlet of the second three-way connector via a solenoid valve.

[0021] The second flow limiting device has its inlet connected to the outlet of the fluorescence measuring device, and its outlet connected to the second inlet of the second tee connector.

[0022] The outlet of the second three-way connector is connected to the inlet of the exhaust mechanism.

[0023] Optionally, the interfering component removal device is a hydrocarbon remover;

[0024] The gas state conversion and enrichment device includes a pyrolyzer and a gas enricher;

[0025] The fluorescence measuring device is a fluorescence measuring instrument;

[0026] The current limiting device is a capillary current limiting structure;

[0027] The exhaust mechanism is a pneumatic diaphragm pump.

[0028] Optionally, a sensor group is provided between the flow limiting device and the second gas path conversion mechanism, and between the flow limiting device and the fluorescence measuring device, for measuring the gas flow rate and gas pressure in the corresponding pipe;

[0029] A third tee connector is provided between the first gas path conversion mechanism and the gas delivery pipeline to be tested;

[0030] A mass flow meter is installed between the first gas path conversion mechanism and the inert gas source to control the flow rate of the inert gas.

[0031] The present invention also provides a measurement method based on a constant current fluorescence measurement system under a slight negative pressure state, the method comprising:

[0032] Obtain the initial estimated concentration and gas composition of the gas to be tested;

[0033] Based on the initial estimated concentration and the gas composition, a measurement mode is determined, including a conventional measurement mode, a conversion measurement mode, and an enrichment measurement mode.

[0034] The determination of the measurement mode includes:

[0035] If the initial estimated concentration is greater than or equal to the set threshold and there are components in the gas composition that can be measured by fluorescence, then the measurement mode is determined to be the conventional measurement mode.

[0036] If the gas composition contains components whose concentration cannot be directly obtained through fluorescence measurement, then the measurement mode is determined to be the conversion measurement mode.

[0037] If the initial estimated concentration is less than the set threshold, then the measurement mode is determined to be the enrichment measurement mode;

[0038] The concentration of the gas to be tested is measured by controlling the constant current fluorescence measurement system based on the measurement mode.

[0039] Optionally, the conventional measurement modes include:

[0040] Control the solenoid valve to close;

[0041] Adjust the opening and closing states of the first gas path switching mechanism and the second gas path switching mechanism so that the movement path of the gas to be tested is as follows: gas to be tested delivery pipeline, interfering component removal device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

[0042] Optionally, the conversion measurement mode includes:

[0043] Control the solenoid valve to close;

[0044] Adjust the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism so that the movement path of the gas to be tested is as follows: gas delivery pipeline, gas form conversion and enrichment device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

[0045] Optionally, the enrichment measurement mode includes:

[0046] Control the solenoid valve to turn on;

[0047] Adjust the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism so that the movement path of the gas to be tested is as follows: gas to be tested delivery pipeline, gas form conversion and enrichment device, first flow limiting device and exhaust mechanism.

[0048] After a preset time, the control solenoid valve closes, and the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism are adjusted. The inert gas source is controlled to supply gas to the gas form conversion and enrichment device, and the gas delivery pipeline to be tested is controlled to stop supplying gas to the gas form conversion and enrichment device, so that the movement path of the gas to be tested is adjusted to: gas form conversion and enrichment device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

[0049] This technical solution, through the cooperation of a flow-limiting device and an exhaust mechanism, enables the fluorescence measurement device to be in a negative pressure state, maintaining the gas stability of the measurement system and effectively reducing the impact of gas pressure fluctuations on the fluorescence system measurement process during rapid response and sample gas switching. At the same time, the interference component removal device removes components such as macromolecules and polymers that interfere with the target gas, improving the measurement accuracy and sensitivity of the system. Furthermore, the gas speciation conversion and enrichment device converts components that do not have fluorescence effects and enriches components with excessively low concentrations, thereby achieving accurate measurement of the concentration of different types of sample gases and having a wide range of applications.

[0050] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0051] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0052] Figure 1 This is a schematic diagram of the overall structure of the constant current fluorescence measurement system under a slight negative pressure state provided by the present invention;

[0053] Figure 2 This is a schematic diagram of the specific structure of the first constant current fluorescence measurement system under a slight negative pressure state provided by the present invention;

[0054] Figure 3 This is a schematic diagram of the specific structure of the second type of constant current fluorescence measurement system under a slight negative pressure state provided by the present invention;

[0055] Figure 4 This is a flowchart of the measurement method based on a constant current fluorescence measurement system under a slight negative pressure state provided by the present invention;

[0056] Figure 5 This is a flowchart of the process for determining the measurement mode provided by the present invention.

[0057] Explanation of reference numerals in the attached figures

[0058] 1-First gas path conversion mechanism; 2-Gas delivery pipeline to be tested;

[0059] 3-Inert gas source; 4-Interference component removal device;

[0060] 5-Gas speciation conversion and enrichment device; 6-Fluorescence measurement device;

[0061] 7-Flow limiting device; 8-Second air path switching mechanism;

[0062] 9-Exhaust mechanism; 11-First tee connector;

[0063] 12-First three-way valve; 51-Cracker;

[0064] 52 - Gas enrichment device; 71 - First flow limiting device;

[0065] 72 - Second flow limiting device; 81 - Second three-way valve;

[0066] 82 - Third three-way valve; 101 - Sensor group;

[0067] 102 - Third tee connector; 103 - Mass flow meter;

[0068] 701 - Second tee connector; 702 - Solenoid valve. Detailed Implementation

[0069] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0070] In the embodiments of the present invention, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use.

[0071] The terms “first,” “second,” “third,” etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0072] The terms "parallel" and "perpendicular" do not mean that the components must be absolutely parallel or perpendicular, but rather that they can be slightly tilted. For example, "parallel" simply means that its direction is more parallel than "perpendicular," not that the structure must be completely parallel, but that it can be slightly tilted.

[0073] The terms "horizontal," "vertical," and "sag" do not imply that a component must be absolutely horizontal, vertical, or sagging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted.

[0074] Furthermore, terms like "roughly" and "basically" are used to indicate that the content does not require absolute precision, but rather allows for a certain degree of deviation. For example, "roughly equal" does not simply mean absolute equality; in actual production and operation, achieving absolute "equality" is difficult, and a certain degree of deviation is generally present. Therefore, besides absolute equality, "roughly equal to" also includes the aforementioned situation where a certain degree of deviation exists. Using this as an example, in other cases, unless otherwise specified, terms like "roughly" and "basically" have similar meanings.

[0075] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0076] Figure 1 This is a schematic diagram of the overall structure of the constant current fluorescence measurement system under a slight negative pressure state provided by the present invention; Figure 2 This is a schematic diagram of the specific structure of the first constant current fluorescence measurement system under a slight negative pressure state provided by the present invention; Figure 3 This is a schematic diagram of the specific structure of the second type of constant current fluorescence measurement system under a slight negative pressure state provided by the present invention; Figure 4 This is a flowchart of the measurement method based on a constant current fluorescence measurement system under a slight negative pressure state provided by the present invention; Figure 5 This is a flowchart of the process for determining the measurement mode provided by the present invention.

[0077] like Figure 1 As shown, this embodiment provides a constant current fluorescence measurement system under a slightly negative pressure state, the system comprising:

[0078] The first gas path conversion mechanism 1 has an air inlet connected to the gas delivery pipeline 2 and the inert gas source 3.

[0079] Interference component removal device 4, the air inlet of which is connected to the air outlet of the first gas path conversion mechanism 1, is used to remove interference components in the gas to be tested.

[0080] The gas form conversion and enrichment device 5 is used to convert the gas form of the gas to be tested and enrich the gas by connecting the inlet of the interfering component removal device 4 to the outlet of the first gas path conversion mechanism 1.

[0081] The fluorescence measuring device 6 has its inlet connected to the outlet of the interfering component removal device 4 and the gas form conversion and enrichment device 5 via a second gas path conversion mechanism 8, and is used to measure the concentration of the gas to be measured.

[0082] The flow limiting device 7 has its inlet connected to the second air path conversion mechanism 8 and the outlet of the fluorescence measuring device 6. The flow limiting device 7 and the exhaust mechanism 9 cooperate to stabilize the airflow of the fluorescence measuring device 6 and to keep the fluorescence measuring device 6 under negative pressure.

[0083] Specifically, in this embodiment, the first gas path switching mechanism 1 switches the on / off state of the pipeline to achieve the connection between the gas to be tested delivery pipeline 2 and the inert gas source 3, thereby realizing the delivery of the gas to be tested through the gas to be tested delivery pipeline 2 and the delivery of inert gas through the inert gas source 3; the interfering component removal device 4 is used to remove interfering components in the test gas, such as hydrocarbons and polycyclic aromatic hydrocarbons, to avoid the influence of hydrocarbons and polycyclic aromatic hydrocarbons on the fluorescence measurement of the test component and improve the accuracy of the measurement; the gas form conversion and enrichment device 5 is used to convert the gas form of components that cannot be directly excited to produce a fluorescence reaction when there are components in the test gas that cannot be fluorescence measured, and then the fluorescence measurement device 6 is used to perform fluorescence measurement on the converted gas to achieve characterization of the original components; for some components with low concentrations, due to their low concentration, If the gas cannot be accurately detected, the corresponding component is enriched by the gas form conversion enrichment device 5, and then analyzed into a high concentration of the corresponding component. Fluorescence measurement is then performed using the fluorescence measurement device 6 to ensure the accuracy of the measurement. Similarly, the second gas path conversion mechanism 8 controls the flow of gas from the interference component removal device 4 and the gas form conversion enrichment device 5 to the fluorescence measurement device 6 by switching the on / off state of the pipeline. After measurement, the gas is output from the outlet of the fluorescence measurement device 6, passes through the flow limiting structure 7 and the exhaust mechanism 9, and is discharged outward. The flow limiting structure 7 and the exhaust mechanism 9 work together to slow down the gas flow rate, so that the gas flow rate entering the fluorescence measurement device 6 is constant. At the same time, a negative pressure is formed at the fluorescence measurement device 6, thereby achieving constant flow of gas in the fluorescence measurement device 6 and ensuring more accurate measurement results.

[0084] The principle of the fluorescence measuring device 6 is as follows: after the gas to be measured enters the measuring chamber of the fluorescence measuring device 6, it is excited by the light emitted by the optical system of the fluorescence measuring device 6 and emits fluorescence. The data acquisition system of the fluorescence measuring device 6 acquires and processes the emitted fluorescence signal, and establishes a linear concentration relationship through photoelectric conversion.

[0085] More specifically, the gas flow rate and pressure of the measuring chamber entering the fluorescence measuring device 6 are determined by the volume of the measuring chamber, the flow limiting structure 7, and the exhaust mechanism 9 of the fluorescence measuring device 6.

[0086] In another embodiment, the measured gas is passed through the exhaust mechanism 9, where it undergoes adsorption or neutralization reaction by the exhaust gas treatment device before being discharged into the atmosphere to reduce gas pollution to the environment.

[0087] Furthermore, such as Figure 2-3 As shown, the first gas path switching mechanism 1 includes:

[0088] First three-way connector 11 and first three-way valve 12;

[0089] The inlet of the first three-way connector 11 is connected to the gas delivery pipeline 2, the first outlet of the first three-way connector 11 is connected to the first inlet of the first three-way valve 12, and the second outlet is connected to the inlet of the interfering component removal device 4.

[0090] The second port of the first three-way valve 12 is connected to the inert gas source 3, and the outlet of the first three-way valve 12 is connected to the inlet of the gas state conversion and enrichment device 5.

[0091] Specifically, in this embodiment, two three-way valves, namely a first three-way connector 11 and a first three-way valve 12, constitute the first gas path conversion mechanism 1. The inlet of the first three-way connector 11 is connected to the gas delivery pipeline 2, the first outlet of the first three-way connector 11 is connected to the first inlet of the first three-way valve 12, and the second outlet is connected to the inlet of the interfering component removal device 4. The second outlet of the first three-way valve 12 is connected to the inert gas source 3, and the outlet of the first three-way valve 12 is connected to the inlet of the gas form conversion and enrichment device 5. This enables the delivery of the gas to be tested to the interfering component removal device 4 or the gas form conversion and enrichment device 5, as well as the delivery of the inert gas to the interfering component removal device 4 or the gas form conversion and enrichment device 5. By controlling the opening and closing of the inlet and outlet of the first three-way valve 12, a combined control is achieved, which has the advantages of simple structure, reduced control complexity, accurate control, and low cost.

[0092] Furthermore, such as Figure 2-3 As shown, the second gas path switching mechanism 8 includes:

[0093] Second three-way valve 81 and third three-way valve 82;

[0094] The first air inlet of the second three-way valve 81 is connected to the air outlet of the interfering component removal device 4, the second air inlet of the second three-way valve 81 is connected to the first air outlet of the third three-way valve 82, and the air outlet of the second three-way valve 81 is connected to the air inlet of the fluorescence measuring device 6.

[0095] The inlet of the third three-way valve 82 is connected to the outlet of the gas state conversion and enrichment device 5, and the second outlet of the third three-way valve 82 is connected to the inlet of the flow limiting device 7.

[0096] Specifically, in this embodiment, two three-way valves, namely a second three-way valve 81 and a third three-way valve 82, constitute the second gas path switching mechanism 8. The first inlet of the second three-way valve 81 is connected to the outlet of the interfering component removal device 4, and the second inlet of the second three-way valve 81 is connected to the first outlet of the third three-way valve 82. The outlet of the second three-way valve 81 is connected to the inlet of the fluorescence measuring device 6. The inlet of the third three-way valve 82 is connected to the outlet of the gas state conversion and enrichment device 5, and the second outlet of the third three-way valve 82 is connected to the inlet of the flow limiting device 7. This allows the gas to be tested in the interfering component removal device 4 to be transported to the fluorescence measuring device 6, or the gas to be tested in the gas state conversion and enrichment device 5 to be transported to the fluorescence measuring device 6 or to the flow limiting device 7. By controlling the opening and closing of the inlets and outlets of the second three-way valve 81 and the third three-way valve 82, a combined control is achieved, which has the advantages of simple structure, accurate control, and low cost.

[0097] Furthermore, such as Figure 2-3 As shown, the flow limiting device 7 is connected to the air inlet of the exhaust mechanism 9 via a second tee connector 701; the flow limiting device 7 includes:

[0098] The first flow limiting device 71 has its inlet connected to the outlet of the second air path conversion mechanism 8, and its outlet is connected to the first inlet of the second three-way connector 701 via a solenoid valve 702.

[0099] The second flow limiting device 72 has its air inlet connected to the air outlet of the fluorescence measuring device 6, and its air outlet connected to the second air inlet of the second tee connector 701.

[0100] The outlet of the second three-way connector 701 is connected to the inlet of the exhaust mechanism 9.

[0101] Specifically, in this embodiment, the flow limiting device 7 is configured as a first flow limiting device 71 and a second flow limiting device 72 to achieve different flow control effects for different pipelines. More specifically, both the first flow limiting device 71 and the second flow limiting device 72 are configured as capillary flow limiting structures. The specific structural parameters of the first flow limiting device 71 are: length 2cm, capillary flow limiting orifice diameter 0.33mm~0.35mm, and pressure difference P across the first flow limiting device 71. 前 / P 后Greater than 2.5 times; the specific structural parameters of the second current limiting device 72 are: length 2cm, capillary flow limiting orifice diameter 0.38mm~0.4mm, and pressure difference P across the second current limiting device 72. 前 / P 后 Greater than 2.5 times. The first current limiting device 71 and the second current limiting device 72, with the above parameter settings, can achieve precise flow control and improve stability.

[0102] Since the second three-way connector 701 does not have the effect of on / off control, a solenoid valve 702 is installed between the air outlet of the first flow limiting device 71 and the first air inlet of the second three-way connector 701 to achieve the on / off control of the corresponding pipeline, thus achieving the effect of simple control method.

[0103] Furthermore, the interfering component removal device 4 is a hydrocarbon remover. Specifically, the hydrocarbon remover is used to remove hydrocarbons in the gas to be tested, so as to reduce the influence on the measurement results and improve the accuracy of fluorescence measurement.

[0104] The gas state conversion and enrichment device 5 includes a pyrolyzer 51 and a gas enricher 52. Specifically, the pyrolyzer 51 and the gas enricher 52 are arranged in parallel to form the gas state conversion and enrichment device 5, such as... Figure 3 As shown, both the inlet and outlet of the pyrolyzer 51 and the gas enrichment unit 52 are equipped with solenoid valves or three-way valves for pipeline opening and closing control. More specifically, in this embodiment, taking the measurement of the concentration of gaseous mercury in a gas as an example, a gas enrichment unit (gold wire) is typically used to adsorb gaseous mercury. After adsorption for a unit time, a high concentration of gaseous mercury is released from the gold amalgam through heating and desorption, thereby increasing the content of gaseous mercury in the gas to be measured. The actual average concentration of gaseous mercury in the gas to be measured per unit time is then calculated proportionally based on the unit operating time of the gas enrichment unit and the flow rate of the incoming gas. For fluorescence measurements of different gas components, the corresponding type of gas enrichment unit 52 can be replaced.

[0105] In another embodiment, the gas state conversion and enrichment device 5 may be omitted, and it may be directly replaced by an independently set pyrolyzer 51 and gas enricher 52.

[0106] The fluorescence measuring device 6 is a fluorescence measuring instrument;

[0107] The current limiting device 7 is a capillary current limiting structure, and the current limiting device 7 can also be specifically set as a capillary tube;

[0108] The exhaust mechanism 9 is a pneumatic diaphragm pump, wherein the ultimate vacuum of the pneumatic diaphragm pump does not exceed 180 mmHg.

[0109] Furthermore, sensor groups 101 are provided between the flow limiting device 7 and the second gas path conversion mechanism 8, and between the flow limiting device 7 and the fluorescence measuring device 6, for measuring the gas flow rate and gas pressure in the corresponding pipelines. Specifically, the sensor group 101 includes a flow sensor and a pressure sensor.

[0110] A third tee connector 102 is provided between the first gas path conversion mechanism 1 and the gas delivery pipeline 2 to be tested. The third tee connector 102 can adjust the flow rate of the gas delivered by the gas delivery pipeline 2 to be tested when the corresponding gas outlet is opened.

[0111] A mass flow meter 103 is provided between the first gas path conversion mechanism 1 and the inert gas source 3 to control the flow rate of the inert gas. Specifically, by using the mass flow meter 103 to control the flow rate of the inert gas output from the inert gas source 3, the control accuracy can be guaranteed, and accurate flow data can be collected during the control process.

[0112] The present invention also provides a measurement method based on a constant current fluorescence measurement system under a slight negative pressure state, such as... Figure 4 As shown, the method includes:

[0113] Step 101: Obtain the initial estimated concentration and gas composition of the gas to be tested;

[0114] Specifically, in this embodiment, the initial estimated concentration of the gas to be tested can be estimated by production data during the production process or by initial data collected by the sensor; the gas composition can also be estimated by the production reaction during the production process.

[0115] Step 102: Based on the initial estimated concentration and the gas composition, determine the measurement mode, which includes a conventional measurement mode, a conversion measurement mode, and an enrichment measurement mode;

[0116] In this embodiment, such as Figure 5 As shown, the measurement mode is determined in the following ways, including:

[0117] If the initial estimated concentration is greater than or equal to the set threshold and there are components in the gas composition that can be measured by fluorescence, then the measurement mode is determined to be the conventional measurement mode.

[0118] Specifically, when the initial estimated concentration is greater than or equal to the set threshold, it indicates that the component to be tested has a certain proportion in the gas to be tested. Therefore, it is then determined whether the component can be accurately measured by fluorescence measurement. If it is, fluorescence measurement can be performed using the conventional measurement mode.

[0119] If the gas composition contains gases whose concentration cannot be directly obtained through fluorescence measurement, then the measurement mode is determined to be the conversion measurement mode.

[0120] Similarly, if there are components in the gaseous composition whose concentration cannot be obtained through fluorescence measurement, it means that accurate calculation cannot be performed directly using fluorescence measurement. Therefore, a gaseous composition conversion enrichment device (pyrolysis device) is used to convert the gaseous composition into components whose concentration can be obtained through fluorescence measurement before calculation.

[0121] If the initial estimated concentration is less than the set threshold, then the measurement mode is determined to be the enrichment measurement mode;

[0122] Similarly, for the measurement of some ultra-trace or extremely low concentration gas components, the system cannot obtain a linear relationship between fluorescence signal and concentration through direct measurement. Therefore, an enrichment method is used to accumulate the concentration of the gas component, and then an inert carrier gas is used to load the accumulated high-concentration gas component into the measurement system for measurement. Thus, if the initial estimated concentration is less than the set threshold, the proportion of the component in the analyte gas may not be accurately measured by fluorescence measurement because it is too low. Therefore, a gas speciation enrichment device (gas enricher) is used to enrich the component, increase its proportion, and then perform accurate measurement.

[0123] Step 103: Based on the measurement mode, control the constant current fluorescence measurement system to measure the concentration of the gas to be tested.

[0124] Furthermore, the conventional measurement modes include:

[0125] Control the solenoid valve to close;

[0126] Adjust the opening and closing states of the first gas path switching mechanism and the second gas path switching mechanism so that the movement path of the gas to be tested is as follows: gas to be tested delivery pipeline, interfering component removal device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

[0127] Specifically, firstly, the solenoid valve 702 is closed, preventing the gas to be measured from flowing through it. Then, the first three-way valve 12 is closed at point A and open at point B, the second three-way valve 81 is open at point A and closed at point B, and the third three-way valve 82 is closed at point A and open at point B. The gas to be measured enters the gas path system from the gas delivery pipeline 2 through the first three-way connector 11, while the other side is vented. After passing through the first three-way valve 12, it enters the interference component removal device 4, where differential pressure osmosis is used to remove gas components such as macromolecules and polymers that may interfere with the measurement of the target gas. Subsequently, the gas passes through the second three-way valve 81 and enters the measurement chamber of the fluorescence measurement device 6 through the inlet for concentration measurement. After passing through the outlet of the fluorescence measurement device 6, the flow sensor and pressure sensor monitor the flow and pressure at the front end of the second flow limiting device 72. After passing through the second flow limiting device 72, the gas enters the exhaust mechanism 9 (diaphragm power source) through the second three-way connector 701, and then the entire gas is discharged from the measurement system. The flow rate of the gas entering the fluorescence measuring device 6 and the pressure of the measuring chamber are determined by the volume of the measuring chamber of the fluorescence measuring device 6, the parameters of the second flow limiting device 72 and the exhaust mechanism 9.

[0128] Furthermore, the conversion measurement mode includes:

[0129] Control the solenoid valve to close;

[0130] Adjust the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism so that the movement path of the gas to be tested is as follows: gas delivery pipeline, gas form conversion and enrichment device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

[0131] Specifically, firstly, the solenoid valve 702 is closed, preventing the gas to be tested from flowing through it. Secondly, the first three-way valve 12 is opened at point A and closed at point B, the second three-way valve 81 is closed at point A and opened at point B, and the third three-way valve 82 is opened at point A and closed at point B. The gas to be tested enters the gas path system from the gas delivery pipeline 2 through the first three-way connector 11, while the other side of the sample gas is discharged. After passing through the first three-way valve 12, it enters the gas state conversion and enrichment device 5, where it is converted into a gas by oxidation pyrolysis or hydrogenation pyrolysis. The target gas component for fluorescence measurement is then introduced. The gas enters the measurement chamber of the fluorescence measurement device 6 through the inlet of the third three-way valve 82, then through the second three-way valve 81, for concentration measurement. After passing through the outlet of the fluorescence measurement device 6, flow and pressure sensors monitor the flow rate and pressure at the front end of the second flow limiting device 72. After passing through the second flow limiting device 72, the gas enters the exhaust mechanism 9 (diaphragm power source) through the second three-way connector 701, and then the entire gas is discharged from the measurement system. The flow rate and pressure of the gas entering the fluorescence measurement device 6 are determined by the volume of the measurement chamber of the fluorescence measurement device 6, the parameters of the second flow limiting device 72, and the exhaust mechanism 9.

[0132] Furthermore, the enrichment measurement mode includes:

[0133] Control the solenoid valve to turn on;

[0134] Adjust the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism so that the movement path of the gas to be tested is as follows: gas to be tested delivery pipeline, gas form conversion and enrichment device, first flow limiting device and exhaust mechanism.

[0135] After a preset time, the control solenoid valve closes, and the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism are adjusted. The inert gas source is controlled to supply gas to the gas form conversion and enrichment device, and the gas delivery pipeline to be tested is controlled to stop supplying gas to the gas form conversion and enrichment device, so that the movement path of the gas to be tested is adjusted to: gas form conversion and enrichment device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

[0136] Specifically, it includes: a gas enrichment stage and a measurement stage:

[0137] The gas enrichment stage includes:

[0138] First, the solenoid valve 702 is turned on, preventing the gas to be tested from flowing through it. Second, the first three-way valve 12 is opened at point A and closed at point B, the second three-way valve 81 is closed at point A and opened at point B, and the third three-way valve 82 is opened at point A and closed at point B. The gas to be tested enters the gas path system from the gas delivery pipeline 2 through the first three-way connector 11, while the other side is vented. After passing through the first three-way valve 12, it enters the gas form conversion and enrichment device 5. The gas form conversion and enrichment device 5 enriches the gas components, increasing the content of fluorescent components in the gas to be tested. Then, the gas enters the exhaust mechanism 9 (diaphragm power source 10) sequentially from the third three-way valve 82, the second flow limiting device 71, the solenoid valve 702, and one side of the second three-way connector 701. Finally, the gas is discharged from the measurement system as a whole.

[0139] After a preset time, gas enrichment is complete, and the measurement phase begins.

[0140] First, the control solenoid valve 702 is disconnected, preventing the gas to be measured from flowing through it. Second, the first three-way valve 12 is closed at point A and open at point B, the second three-way valve 81 is closed at point A and open at point B, and the third three-way valve 82 is open at point A and closed at point B. The mass flow meter 103 is activated, and the inert gas source 3 flows from the first three-way valve 12 through the mass flow meter 103 into the gas form conversion and enrichment device 5, where it mixes with the high-concentration components after enrichment and analysis. The mixed gas passes through the third three-way valve 82, then through the second three-way valve 81, and enters the measurement chamber of the fluorescence measurement device 6 through the inlet for concentration measurement. After passing through the outlet of the fluorescence measurement device 6, the flow sensor and pressure sensor monitor the flow and pressure at the front end of the second flow limiting device 72. After passing through the second flow limiting device 72, the gas enters the exhaust mechanism 9 (diaphragm power source) through the second three-way connector 701, and then the entire gas is discharged from the measurement system. The flow rate of the gas entering the fluorescence measuring device 6 and the pressure of the measuring chamber are determined by the volume of the measuring chamber of the fluorescence measuring device 6, the parameters of the second flow limiting device 72 and the exhaust mechanism 9.

[0141] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0142] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0143] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0144] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A constant current fluorescence measurement system under a slightly negative pressure state, characterized in that, The system includes: The first gas path conversion mechanism (1) has an air inlet connected to the gas delivery pipeline (2) and the inert gas source (3). Interference component removal device (4), the inlet of which is connected to the outlet of the first gas path conversion mechanism (1), is used to remove interference components in the gas to be tested. Gas form conversion and enrichment device (5), the inlet of the gas form conversion and enrichment device (5) is connected to the outlet of the first gas path conversion mechanism (1), and is used to convert the gas form of the gas to be tested and enrich the gas. The fluorescence measuring device (6) has its inlet connected to the outlet of the interfering component removal device (4) and the outlet of the gas form conversion enrichment device (5) via a second gas path conversion mechanism (8) for measuring the concentration of the gas to be measured. A flow limiting device (7) is provided, the air inlet of which is connected to the air outlet of the second air path conversion mechanism (8) and the air outlet of the fluorescence measuring device (6). The air outlet of the flow limiting device (7) is connected to the exhaust mechanism (9). The flow limiting device (7) and the exhaust mechanism (9) cooperate with each other to stabilize the air inlet flow of the fluorescence measuring device (6) and to make the fluorescence measuring device (6) negative pressure. The flow limiting device (7) is connected to the air inlet of the exhaust mechanism (9) via a second tee connector (701); the flow limiting device (7) includes: The first flow limiting device (71) has its inlet connected to the outlet of the second air path conversion mechanism (8), and its outlet is connected to the first inlet of the second three-way connector (701) via a solenoid valve (702). The second flow limiting device (72) has its inlet connected to the outlet of the fluorescence measuring device (6), and its outlet connected to the second inlet of the second tee connector (701). The outlet of the second three-way connector (701) is connected to the inlet of the exhaust mechanism (9).

2. The constant current fluorescence measurement system under a slightly negative pressure state according to claim 1, characterized in that, The first gas path switching mechanism (1) includes: First three-way connector (11) and first three-way valve (12); The inlet of the first three-way connector (11) is connected to the gas delivery pipeline (2) to be tested, the first outlet of the first three-way connector (11) is connected to the first inlet of the first three-way valve (12), and the second outlet is connected to the inlet of the interference component removal device (4). The second port of the first three-way valve (12) is connected to the inert gas source (3), and the outlet of the first three-way valve (12) is connected to the inlet of the gas state conversion and enrichment device (5).

3. The constant current fluorescence measurement system under a slightly negative pressure state according to claim 1, characterized in that, The second gas path switching mechanism (8) includes: The second three-way valve (81) and the third three-way valve (82); The first inlet of the second three-way valve (81) is connected to the outlet of the interfering component removal device (4), the second inlet of the second three-way valve (81) is connected to the first outlet of the third three-way valve (82), and the outlet of the second three-way valve (81) is connected to the inlet of the fluorescence measuring device (6). The inlet of the third three-way valve (82) is connected to the outlet of the gas state conversion and enrichment device (5), and the second outlet of the third three-way valve (82) is connected to the inlet of the flow limiting device (7).

4. The constant current fluorescence measurement system under a slightly negative pressure state according to claim 1, characterized in that, The interfering component removal device (4) is a hydrocarbon remover; The gas state conversion and enrichment device (5) includes a pyrolyzer (51) and a gas enricher (52). The fluorescence measuring device (6) is a fluorescence measuring instrument; The current limiting device (7) is a capillary current limiting structure; The exhaust mechanism (9) is a pneumatic diaphragm pump.

5. The constant current fluorescence measurement system under a slightly negative pressure state according to claim 1, characterized in that, Sensor groups (101) are provided between the flow limiting device (7) and the second gas path conversion mechanism (8), and between the flow limiting device (7) and the fluorescence measuring device (6), for measuring the gas flow rate and gas pressure in the corresponding pipes; A third tee connector (102) is provided between the first gas path conversion mechanism (1) and the gas delivery pipeline (2) to be tested. A mass flow meter (103) is provided between the first gas path conversion mechanism (1) and the inert gas source (3) to control the flow rate of the inert gas.

6. A measurement method based on a constant current fluorescence measurement system under a slightly negative pressure state, applied to the constant current fluorescence measurement system under a slightly negative pressure state as described in any one of claims 1-5, characterized in that, The method includes: Obtain the initial estimated concentration and gas composition of the gas to be tested; Based on the initial estimated concentration and the gas composition, a measurement mode is determined, including a conventional measurement mode, a conversion measurement mode, and an enrichment measurement mode. The determination of the measurement mode includes: If the initial estimated concentration is greater than or equal to the set threshold and there are components in the gas composition that can be measured by fluorescence, then the measurement mode is determined to be the conventional measurement mode. If the gas composition contains components whose concentration cannot be directly obtained through fluorescence measurement, then the measurement mode is determined to be the conversion measurement mode. If the initial estimated concentration is less than the set threshold, then the measurement mode is determined to be the enrichment measurement mode; The concentration of the gas to be tested is measured by controlling the constant current fluorescence measurement system based on the measurement mode.

7. The measurement method based on a constant current fluorescence measurement system under a slight negative pressure state according to claim 6, characterized in that, The conventional measurement modes include: Control the solenoid valve to close; Adjust the opening and closing states of the first gas path switching mechanism and the second gas path switching mechanism so that the movement path of the gas to be tested is as follows: gas to be tested delivery pipeline, interfering component removal device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

8. The measurement method based on a constant current fluorescence measurement system under a slight negative pressure state according to claim 6, characterized in that, The conversion measurement modes include: Control the solenoid valve to close; Adjust the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism so that the movement path of the gas to be tested is as follows: gas delivery pipeline, gas form conversion and enrichment device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

9. The measurement method based on a constant current fluorescence measurement system under a slight negative pressure state according to claim 6, characterized in that, The enrichment measurement mode includes: Control the solenoid valve to turn on; Adjust the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism so that the movement path of the gas to be tested is as follows: gas to be tested delivery pipeline, gas form conversion and enrichment device, first flow limiting device and exhaust mechanism. After a preset time, the control solenoid valve closes, and the opening and closing states of the first gas path conversion mechanism and the second gas path conversion mechanism are adjusted. The inert gas source is controlled to supply gas to the gas form conversion and enrichment device, and the gas delivery pipeline to be tested is controlled to stop supplying gas to the gas form conversion and enrichment device, so that the movement path of the gas to be tested is adjusted to: gas form conversion and enrichment device, fluorescence measurement device, second flow limiting device and exhaust mechanism.

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