Automatic SUMMA tank sampling system triggered based on monitoring instrument

Abstract

The invention relates to an automatic SUMMA tank sampling system triggered based on a monitoring instrument, which is applied to the technical field of environmental monitoring, and is characterized in that an active air extractor is started to assist sample introduction during sampling, so that the sampling time of several minutes required by the traditional natural negative pressure is shortened to several seconds or tens of seconds, the sampling efficiency is remarkably improved, and the sampling time is shortened. The method can effectively capture and collect representative samples of transient high-concentration pollution events which are easy to miss by a conventional method. Secondly, real-time feedback and closed-loop control are carried out on the pressure in the sampling container through a pressure sensor, sampling can be automatically and accurately stopped when the preset sampling pressure is reached, accurate and automatic control of the sampling process is achieved, the consistency and repeatability of the sampling volume each time are guaranteed, and the sampling efficiency is improved. And the sampling quantity difference caused by inaccurate time control or manual operation is avoided. In addition, monitoring, triggering, rapid sampling and accurate cut-off are integrated into a full-automatic process, manual intervention is not needed, and response is rapid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental monitoring, and in particular to an automatic SUMMA can sampling system based on monitoring instrument triggering. BACKGROUND

[0002] Volatile organic compounds (VOCs) are a class of organic compounds that can easily volatilize into the air at room temperature and pressure, usually referring to organic compounds with a saturated vapor pressure greater than 70 Pa and a boiling point lower than 260℃. The sources of volatile organic compounds are extensive, including traffic exhaust emissions, industrial production processes, solvent use, petrochemical storage and transportation, and fuel evaporation. In the atmospheric environment, volatile organic compounds are important precursors of ozone and secondary organic aerosols (SOA), which have a significant impact on regional air quality and public health; at the same time, some volatile organic compounds (such as benzene, toluene, xylene, etc.) are carcinogenic or potentially toxic, and long-term exposure can cause serious health risks. Therefore, accurate monitoring and sample collection of volatile organic compounds are of great significance for pollution source analysis, atmospheric chemical process research, and environmental management decision-making.

[0003] In actual volatile organic compound monitoring, one type is online monitoring, which uses proton transfer reaction mass spectrometry (PTR-MS), gas chromatography-mass spectrometry (GC-MS), etc. high time resolution instruments for real-time detection of gases, which can provide concentration change information at seconds to hours; the other type is offline sampling analysis, such as using SUMMA can or Tenax tube to collect samples, and then sending them to the laboratory for qualitative and quantitative analysis of each component by gas chromatography-mass spectrometry (GC-MS / FID / ECD, etc.). The former has advantages in timeliness and sensitivity, but is subject to expensive equipment, complex maintenance, and difficulty in large-scale deployment; the latter has the characteristics of strong universality and high component analysis capability, but the triggering timing and sampling efficiency of the sampling link become the key problems for capturing transient pollution events.

[0004] In offline sampling analysis, the common sampling methods currently include timed sampling, manual sampling, and traditional SUMMA can sampling, but there are obvious deficiencies in the face of complex and transient pollution emission events: timed sampling: performed according to pre-set time intervals, which is easy to be out of sync with transient pollution emissions, often missing accidental or short-time high-concentration plumes, resulting in lack of representativeness of sampling results. Manual sampling: relies on real-time judgment and operation of personnel, but human reaction delay and operation time consumption will cause missed best sampling opportunity, and differences in judgment of different operators will also affect the consistency of sampling results.

[0005] Meanwhile, the sampling of the conventional SUMMA tank relies on the natural negative pressure inside the tank for inflation, and the sampling flow rate is slow, usually taking several minutes to fill, which is not suitable for capturing transient pollution events with a duration of only a few seconds to tens of seconds. In addition, the sampling process is easily affected by wind direction, vehicle speed or source intensity fluctuations, resulting in temporal and spatial mismatch.

[0006] In summary, the existing off-line sampling method of volatile organic compounds generally has the problems of slow response, low efficiency, and difficulty in timely locking pollution plume, especially when facing transient emission events, it is difficult to obtain accurate and effective samples, which limits the accuracy of pollution source analysis and atmospheric process research. SUMMARY

[0007] Therefore, the purpose of the present application is to provide an automatic SUMMA tank sampling system based on monitoring instrument triggering, to solve the problems of slow response, low efficiency, and difficulty in timely locking pollution plume of the existing off-line sampling method of volatile organic compounds.

[0008] The present application provides an automatic SUMMA tank sampling system based on monitoring instrument triggering, which comprises: A gas path system comprising a sampling main pipe and sampling branches, each of the sampling branches is connected between the gas inlet and the gas outlet of the sampling main pipe at one end, and is connected with a pre-vacuumized sampling container at the other end, and a first electromagnetic valve is arranged at the connection port of each sampling branch and the pre-vacuumized sampling container; A second electromagnetic valve is arranged at the gas outlet of the sampling main pipe; A positive air sampling device is arranged for sampling the ambient gas from the gas inlet of the sampling main pipe; A high time resolution monitoring instrument is arranged for monitoring the concentration of the specified target pollutant; A controller is arranged in communication connection with the high time resolution monitoring instrument, for receiving the concentration monitoring data of the specified target pollutant sent by the high time resolution monitoring instrument; The controller is also in communication connection with the first electromagnetic valve and the second electromagnetic valve respectively, for controlling the opening or closing of the first electromagnetic valve and the second electromagnetic valve; A first pressure sensor is arranged in the pre-vacuumized sampling container, and the first pressure sensor is connected with the controller, for sending the collected sampling container pressure data to the controller; The controller is arranged to control the second electromagnetic valve to be closed and the first electromagnetic valve to be opened when the concentration monitoring data of the specified target pollutant meets the preset triggering condition, and the positive air sampling device is arranged to run to quickly sample the ambient gas to be tested into the pre-vacuumized sampling container. In the sampling process, the controller acquires the pressure reading of the first pressure sensor in real time, and when the pressure in the pre-evacuated sampling container rises to a preset cut-off pressure value, the controller controls the first electromagnetic valve to close to complete sampling.

[0009] Preferably, The controller is further configured to control the first electromagnetic valve to close and the second electromagnetic valve to open in the standby state. The active air pumping device continuously operates to continuously pump ambient gas into the sampling port of the sampling main pipe and discharge it from the gas outlet of the sampling main pipe, thereby maintaining a low delay and low residual state inside the sampling main pipe.

[0010] Preferably, The sampling main pipe further comprises a second pressure sensor connected to the controller and configured to send the air pressure data in the sampling main pipe to the controller.

[0011] Preferably, The controller is further configured to control the second electromagnetic valve and the active air pumping device to perform an automatic cleaning step before sampling starts, according to the air pressure data in the sampling main pipe.

[0012] Preferably, The automatic cleaning step comprises: The controller controls the second electromagnetic valve to close and the active air pumping device to continuously operate, and as ambient gas continuously enters the sampling main pipe, the air pressure in the sampling main pipe gradually rises. When the real-time pressure in the sampling main pipe is greater than a preset pressure threshold value according to the pressure monitoring data of the second pressure sensor, the controller controls the second electromagnetic valve to open, thereby instantaneously releasing gas to purge the sampling main pipe.

[0013] Preferably, The preset trigger condition comprises: The controller acquires concentration monitoring data of the target pollutant and determines whether the real-time concentration of the target pollutant is greater than a preset target pollutant concentration threshold value. If it is greater, the trigger condition is met.

[0014] Preferably, The preset trigger condition further comprises: The controller acquires concentration monitoring data of the target pollutant in a preset time period, arranges the concentration data of the target pollutant in the preset time period in ascending order, selects the concentration monitoring data ranked as the Nth as the background concentration of the target pollutant, and in the subsequent target pollutant monitoring process, if the concentration data of the target pollutant is greater than X times the background concentration, the trigger condition is met.

[0015] Preferably, A one-way valve is further arranged in the sampling branch.

[0016] Preferably, The controller is further used for recording parameters related to each sampling process, and the parameters at least include sampling trigger time, sampling duration, trigger condition and pressure change data, and are archived synchronously with the concentration data of the high-time-resolution monitoring instrument.

[0017] The technical scheme provided by the embodiment of the application can include the following beneficial effects: The application shortens the sampling time of several minutes to several seconds or tens of seconds by starting the active air extraction device to assist sampling, significantly improves the sampling efficiency, and can effectively capture and collect representative samples of transient high-concentration pollution events that are easily missed by the previous method. Secondly, the application realizes accurate and automatic control of the sampling process by using the pressure sensor to feedback and close-loop control the pressure in the sampling container, ensures the consistency and repeatability of the sampling volume, and avoids the sampling volume difference caused by inaccurate time control or human operation. In addition, the application integrates monitoring, triggering, fast sampling and accurate cutoff into a full-automatic process without human intervention, and responds quickly.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the application and, together with the specification, serve to explain the principles of the application.

[0020] Figure 1 is a three-dimensional physical structure schematic diagram of a gas sampling system according to an exemplary embodiment; Figure 2 is a functional module block diagram of an automated SUMMA canister sampling system based on a monitoring instrument trigger according to another exemplary embodiment; Figure 3 is a signaling interaction timing diagram of a gas sampling method according to another exemplary embodiment; In the attached diagram: 10 - mobile frame, 20 - SUMMA tank / vacuum sampling container, 30 - solenoid valve assembly, 40 - gas pipeline, 50 - pressure sensor, 60 - controller unit. Detailed Implementation

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0022] Example 1 Please see Figure 1 and Figure 2 ,in, Figure 1 This is a three-dimensional physical structure diagram of the gas sampling system provided in the embodiments of this application. Figure 2 This is the functional block diagram of the system, which mainly includes: at least one vacuum sampling container, a gas path system, a controller, an active pumping device, and a pressure sensor.

[0023] In one embodiment of this application, such as Figure 1 As shown, the physical structure of the system is integrated onto a mobile frame 10 with casters, facilitating transportation and rapid deployment between different monitoring points. Six specially passivated 6-liter SUMMA canisters are fixedly mounted on the mobile frame 10 as vacuum sampling containers 20. It is understood that these SUMMA canisters 20 are pre-evacuated to a high vacuum (e.g., below 50 mTorr) before use for sampling.

[0024] The core of the gas path system consists of gas path pipe 40 and solenoid valve assembly 30. Gas path pipe 40 is made of corrosion-resistant, low-adsorption stainless steel tubing and includes a main sampling pipe and six branch pipes connected to each SUMMA canister 20. Solenoid valve assembly 30 consists of multiple two-way or three-way solenoid valves (the first solenoid valve mentioned above) installed on each branch pipe for precise control of the connection between the corresponding SUMMA canister 20 and the main sampling pipe. Additionally, an exhaust valve (the second solenoid valve mentioned above) controlled by a controller is located at the end of gas path pipe 40.

[0025] The controller, as the control core of the whole system, in this embodiment, can be implemented by an industrial computer installed in the controller unit 60. The industrial computer runs a special control software developed based on a graphical programming language, which has a user interface allowing the operator to set various parameters such as trigger conditions, cutoff pressure, cleaning program, etc. The controller establishes a communication connection with a high time resolution monitoring instrument through an RS-485 serial bus. Specifically, in this embodiment, the monitoring instrument is a proton transfer reaction time-of-flight mass spectrometer, which can measure the concentrations of various volatile organic compounds such as benzene, toluene, etc. in the environment in real time with a time resolution of seconds. The controller receives the target pollutant concentration monitoring data sent by the monitoring instrument in real time at a frequency of 1 Hz via the communication connection.

[0026] The active air extraction device in this embodiment is a high-performance oil-free diaphragm vacuum pump, whose air extraction port is connected to the sampling main pipe of the gas path pipeline 40. The function of the vacuum pump is to provide additional suction force to overcome the pipeline resistance during sampling, so as to quickly fill the environmental gas into the vacuum sampling container 20.

[0027] The pressure sensor in this embodiment is a high-precision digital pressure gauge, which has a measurement range covering vacuum to positive pressure and a digital signal output interface. As shown in Figure 1 , the pressure sensor (labeled as 50 in the figure) is installed on the sampling main pipe, and its position can accurately reflect the pressure change inside the vacuum sampling container 20 connected thereto. Another feasible solution is that the pressure sensor includes two, which are respectively arranged in the sampling main pipe of the gas path pipeline 40 and in the vacuum sampling container 20, so as to respectively obtain the pressure changes in the sampling main pipe and the vacuum sampling container 20. Correspondingly, the pressure sensor is connected with the controller to transmit the pressure readings to the controller in real time.

[0028] The following will be described in detail Figure 3 , a kind of fast automatic gas sampling method based on monitoring trigger provided in this embodiment. Figure 3 The signaling interaction timing diagram of the method in a sampling event.

[0029] After the system is deployed and started, it enters a standby monitoring state. In this state, to minimize the sampling response delay, the controller executes a standby dynamic refresh program. Specifically, all the electromagnetic valves connected to the SUMMA canister 20 are in a closed state, and the exhaust valve at the end of the gas path pipeline 40 is opened. The controller controls the active air suction device to run continuously, so that the ambient air to be measured is sucked from the air inlet of the sampling main pipe, flows through the entire sampling main pipe, and is finally discharged from the end exhaust port. In this way, it can be ensured that the gas in the sampling main pipe is always dynamically synchronized with the ambient air, thereby ensuring the freshness and representativeness of the gas in the pipeline.

[0030] In the standby state, the controller receives the pollutant concentration monitoring data sent by the high-time-resolution monitoring instrument in real time through the RS-485 bus. Then, the logic program in the controller judges the received data. The preset trigger condition in this embodiment is that the concentration value of the pollutant exceeds 50 ppb for 3 seconds in a row; another possible trigger condition is to obtain the concentration monitoring data of the target pollutant within 10 minutes, assume that there are 100 pollutant concentration data, then arrange the 100 pollutant concentration data in order from small to large, select the concentration data ranked 10th as the background data, and in the subsequent monitoring process, if the concentration data of the target pollutant is greater than X (X usually takes a value in the interval of 4-10) times the background concentration at any time, the trigger condition is met.

[0031] When the monitoring data meets the preset trigger condition at a certain time (for example, the trigger time T0 shown in FIG. 5), the controller judges that the monitoring data meets the preset trigger condition, and the system immediately responds and automatically enters the sampling preparation phase. Figure 3

[0032] Before formal sampling, in order to eliminate the possible residual pollutants in the pipeline and ensure the purity of the sample, the controller executes an automatic pipeline cleaning program. In this embodiment, the cleaning program uses a pressurized purging method using the active air suction device. The specific operation is as follows: the controller first issues an instruction to close the exhaust valve (second electromagnetic valve) at the end of the gas path pipeline 40, at which time the sampling main pipe forms a sealed cavity; then, the controller continues to drive the active air suction device to run, and since the air inlet is still open to the atmosphere, the vacuum pump pumps ambient air into the sealed sampling main pipe to pressurize it. The controller simultaneously monitors the reading of the pressure sensor (or the second pressure sensor), and when the pressure in the pipe reaches a preset pressure value (for example, 28 psi), the controller immediately opens the end exhaust valve. Due to the large pressure difference between the inside and outside of the pipe, the high-pressure gas in the pipe is instantly ejected from the exhaust port, and the powerful gas flow can effectively purge and carry away the particulate matter or residual pollutants attached to the inner wall of the pipeline. The cleaning process can be completed within a few seconds.

[0033] ​After the cleaning procedure is completed, the system immediately enters the formal rapid sampling phase, such as... Figure 3 As shown, at the start of sampling (T1), the controller first selects an unused, vacuum-sealed SUMMA canister 20 (e.g., canister 1), and then sends an electrical signal to open the solenoid valve (first solenoid valve) connected to that canister. Simultaneously, the controller ensures the active vacuum pump is operational. At this time, the ambient air to be measured is rapidly drawn into SUMMA canister 20 1 under the combined action of two forces: the vacuum negative pressure of SUMMA canister 20 itself, and the strong suction force provided by the active vacuum pump. This "assisted negative pressure sampling" method results in a sampling flow rate much greater than that of traditional natural negative pressure sampling, thus significantly shortening the sampling time.

[0034] During the rapid pumping of gas into the SUMMA tank 20, the controller acquires pressure readings from the pressure sensor (or the first pressure sensor) in real time at a high frequency (e.g., 10 times per second). As gas continuously enters, the pressure inside the SUMMA tank 20 rises rapidly from a near-absolute vacuum state, such as... Figure 3 As shown in the pressure change curve from T1 to T2, the controller compares the real-time pressure reading with a preset cutoff pressure value P_cutoff. In this embodiment, the cutoff pressure value P_cutoff is set to 18 psi. It should be noted that this pressure value can ensure that a sufficient volume of gas sample is collected for laboratory analysis, while avoiding sample composition changes or safety risks that may be caused by excessive pressurization.

[0035] When the controller determines that the pressure inside the SUMMA tank 20 has risen to or exceeded 18 psi (e.g. Figure 3 (As shown in the sampling completion time T2). Within microseconds, the controller cuts off the power supply to the solenoid valve of SUMMA tank No. 1, causing it to close rapidly and thus precisely terminating the sampling process. Simultaneously, the controller can also choose to stop the operation of the active extraction device or return it to standby dynamic refresh state. The entire process from triggering to sampling completion is expected to be completed within 15 seconds, thus successfully capturing a representative gas sample of a transient high-concentration pollution event.

[0036] Finally, after the sampling is completed, the controller records and archives the data. The controller generates a record associated with this sampling (i.e., SUMMA canister No. 1) on its internal memory or external storage device. The record details all the key parameters related to this sampling process, including at least: sampling canister number (No. 1), sampling trigger time (specific timestamp of T0), trigger condition (pollutant concentration > 50 ppb), sampling start time (T1), sampling end time (T2), sampling duration (T2-T1), final cut-off pressure (18 psi), and complete pressure change data during T1 to T2. More importantly, the controller 100 correlates and synchronously archives these sampling process parameters with the detailed concentration data (e.g., second-level concentration curve within one minute before and after T0) corresponding to the sampling period obtained from the high-time-resolution monitoring instrument. This provides invaluable information for subsequent laboratory analysis and data traceability, achieving one-to-one correspondence between the sample and real-time concentration.

[0037] After completing a sampling, the system can automatically switch to the next available SUMMA canister 20 to continue performing standby monitoring tasks in preparation for the next automatic trigger sampling.

[0038] Embodiment Two This embodiment provides a variant of the fast automated gas sampling system based on monitoring triggers. The main difference lies in the implementation of the control core, aiming to provide a system with lower cost, higher integration and more robust durability, especially suitable for long-term unattended fixed site deployment.

[0039] In this embodiment, the overall functional modules and working principles of the system are basically consistent with those of Embodiment One, also including vacuum sampling containers 20, gas path systems, active air pumping devices, and pressure sensors, etc. The main difference lies in that the industrial computer as the controller in Embodiment 1 is replaced by a programmable logic controller.

[0040] It can be understood that the programmable logic controller is a digital operation electronic system specially designed for industrial environments, with high reliability, strong anti-interference ability, and flexible programming characteristics. It communicates with the high-time-resolution monitoring instrument through its integrated Ethernet interface. As an optional implementation, in this embodiment, the monitoring instrument is a G2207 gas concentration analyzer from Picarro Company, used to measure the concentrations of methane and ethane simultaneously. The programmable logic controller obtains the concentration data of these two gases from the analyzer in real time through Ethernet protocol (such as Modbus TCP / IP).

[0041] The input / output modules of the programmable logic controller are connected to other components of the system. Among them, the digital output module of the programmable logic controller drives the power switch of the solenoid valve group 30 and the active air exhaust device through the relay; the analog or digital input module is used to receive the pressure signal from the pressure sensor.

[0042] The automation control logic of the system is pre-programmed and fixed in the memory of the programmable logic controller, usually using languages such as ladder diagram or structured text. In this embodiment, the preset trigger condition is set to be more complex to show the flexibility of the system. The trigger condition is set as follows: when the monitored methane concentration exceeds 2 ppm, and the concentration ratio of ethane to methane is greater than a certain threshold (for example, 0.1), the sampling is triggered. This composite condition helps to more accurately identify pollution events from specific sources (such as natural gas leaks).

[0043] The working process is as follows: after the programmable logic controller is powered on, it starts to execute the preset program in a loop. It first enters the standby dynamic refresh mode, controlling the active air exhaust device to continuously exhaust the air path pipeline 40. At the same time, it continuously reads the methane and ethane concentration data of the monitoring instrument through Ethernet. In its internal logic, it calculates the ethane / methane ratio in real time and judges whether the trigger condition is met together with the methane concentration.

[0044] Once the trigger condition is met, the programmable logic controller automatically executes the subsequent steps in sequence: first, it executes the pipeline cleaning program based on the active air exhaust device pressurized purge, then opens the solenoid valve of a selected vacuum sampling container 20, and ensures that the active air exhaust device is running for fast sampling. During the sampling process, it continuously monitors the pressure sensor reading and compares it with the preset cutoff pressure value (for example, also set to 18 psi). When the pressure reaches the cutoff value, the solenoid valve is immediately closed to complete the sampling.

[0045] In addition, the programmable logic controller can also use its data recording function to record the relevant parameters of each sampling (such as trigger time, concentration and ratio at the time of triggering, sampling duration, pressure data, etc.) in the internal storage area, or send it to the remote server for archiving through the network. The operator can also remotely access the programmable logic controller through the network to monitor the system status, view logs or modify trigger logic parameters, etc.

[0046] By using a programmable logic controller as the core, the system of this embodiment has the advantages of smaller size, lower power consumption, and stronger environmental adaptability compared to embodiment one, and does not need to rely on a general operating system, runs more stable and reliable, thus fully demonstrating the realizability of the technical scheme of the present application on different hardware platforms.

[0047] Embodiment three This embodiment provides another variant of the fast automated gas sampling system based on monitoring-triggered, which is characterized by a different way of automatic cleaning of the pipeline, i.e. using an external clean gas source for positive pressure purging. This method is particularly suitable for applications with extremely high requirements for sample background cleanliness, such as trace-level pollutant traceability analysis.

[0048] The system structure of this embodiment is an extension of the first embodiment. As shown in the system function module, Figure 2 a clean gas source is additionally added. Physically, the clean gas source can be a high-pressure gas cylinder filled with high-purity nitrogen (purity 99.999% or higher), and the output pressure is adjusted to a stable value (e.g. 40 psi) by a pressure reducing valve. The outlet of the clean gas source is connected to the inlet end of the gas pipeline 40, i.e. the upstream position of the sampling manifold, through an independent pipeline and an electromagnetic valve (which can be called a cleaning valve) controlled by the controller.

[0049] In this embodiment, the controller, vacuum sampling container 20, active air pumping device, pressure sensor, and core sampling process of the system are exactly the same as in the first embodiment. The only difference is the specific implementation of the automatic cleaning program of the pipeline.

[0050] When the controller determines that the monitoring data meets the trigger condition, it will execute the following positive pressure purging cleaning program: The controller first sends a command to open the cleaning valve connected to the high-purity nitrogen cylinder.

[0051] High-purity nitrogen enters the sampling manifold at a set flow rate (e.g. 5 liters per minute controlled by the pressure reducing valve and pipe diameter) under its own pressure.

[0052] At the same time, the controller ensures that the exhaust valve at the end of the gas pipeline 40 is open.

[0053] High-purity nitrogen flows through the entire sampling manifold and is discharged from the end exhaust port. This process lasts for a predetermined time, for example 30 seconds. During this period, the high flow of clean inert gas can effectively displace and purge the original ambient air in the pipeline and the pollutant molecules that may be adsorbed on the pipe wall.

[0054] After the predetermined cleaning time is up, the controller closes the cleaning valve and immediately closes the end exhaust valve, thus completing the cleaning program.

[0055] This cleaning process completely replaces the method of pressurized purging by using the active air suction device in Embodiment One. It should be noted that the advantage of this positive pressure purging method is that the purging medium used is a high-purity gas of known composition, which itself introduces almost zero background contamination, thus enabling a lower system background value than purging with ambient air, thereby maximizing the purity of subsequent sample collection.

[0056] After the cleaning is completed, the controller opens the electromagnetic valve of the target SUMMA tank 20 and starts the active air suction device for rapid sampling, and the subsequent pressure monitoring and cutoff control process is completely consistent with Embodiment One.

[0057] The technical solution of this embodiment, which uses a clean gas source for positive pressure purging, provides a preferred implementation in specific high-demand scenarios for the present application.

[0058] It can be understood that the same or similar parts in the above embodiments can be mutually referenced, and the contents not described in detail in some embodiments can be referred to the same or similar contents in other embodiments.

[0059] It should be noted that in the description of the present application, the terms "first", "second", etc. are used only for descriptive purposes and should not be understood as indicating or implying relative importance. In addition, in the description of the present application, unless otherwise specified, "a plurality of" means at least two.

[0060] Any process or method descriptions in flow charts or described elsewhere herein can be understood as representing code modules, segments, or portions of code that include one or more executable instructions for implementing specific logic functions (or steps) in the process, and the various embodiments of the present application include additional implementations in which the functions are performed in a different order, or are performed substantially concurrently, or are performed in reverse order, or are performed in an alternative manner, as will be understood by those skilled in the art. It is therefore intended that the following claims encompass all such variations and modifications.

[0061] It should be understood that various parts of the present application can be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following technologies known in the art: discrete logic circuit with logic gates for implementing logical functions on data signals, application specific integrated circuit with suitable combination of logic gates, programmable gate array (PGA), field programmable gate array (FPGA), etc.

[0062] Those skilled in the art can understand that all or part of the steps of the method carried out by the above-mentioned embodiments can be instructed by a program to the relevant hardware, and the program can be stored in a computer readable storage medium. When the program is executed, it includes one of the steps of the method embodiment or a combination thereof.

[0063] In addition, each functional unit in each embodiment of the present application can be integrated into one processing module, or each unit can exist physically independently, or two or more units can be integrated into one module. The integrated module can be realized in the form of hardware or in the form of a software functional module. When the integrated module is realized in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0064] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0065] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present application.

Claims

1. An automated SUMMA can sampling system based on monitoring instrument triggers, characterized in that, The system comprises: an air path system comprising a sampling main pipe and one or more sampling branches, one end of each of the sampling branches being in communication between an air inlet and an air outlet of the sampling main pipe, the other end of each of the sampling branches being in communication with a pre-vacuumized sampling container, a first electromagnetic valve being arranged at a connecting port of each of the sampling branches and the pre-vacuumized sampling container; a second electromagnetic valve being arranged at the air outlet of the sampling main pipe; an active air extraction device for extracting ambient air from the air inlet of the sampling main pipe; a high time resolution monitoring instrument for monitoring the concentration of a specified target pollutant; a controller in communication with the high time resolution monitoring instrument for receiving concentration monitoring data of the specified target pollutant sent by the high time resolution monitoring instrument; the controller is further in communication with the first electromagnetic valve and the second electromagnetic valve respectively for controlling the opening or closing of the first electromagnetic valve and the second electromagnetic valve; a first pressure sensor is arranged in the pre-vacuumized sampling container, the first pressure sensor being connected to the controller for sending collected sampling container air pressure data to the controller; the controller is configured to control the second electromagnetic valve to be closed and the first electromagnetic valve to be opened when the concentration monitoring data of the specified target pollutant meets a preset triggering condition, and to control the active air extraction device to operate to rapidly extract the ambient air to be tested into the pre-vacuumized sampling container; during the sampling process, the controller acquires pressure readings of the first pressure sensor in real time, and controls the first electromagnetic valve to be closed when it is determined that the pressure in the pre-vacuumized sampling container rises to a preset cut-off pressure value, so as to complete the sampling.

2. The system of claim 1, wherein the controller is further configured to control the first electromagnetic valve to be closed and the second electromagnetic valve to be opened in a standby state; the active air extraction device continuously operates to extract ambient air from the sampling port of the sampling main pipe and discharge the ambient air from the air outlet of the sampling main pipe, so as to maintain the inside of the sampling main pipe in a low delay and low residual state.

3. The system of claim 2, wherein a second pressure sensor is further arranged in the sampling main pipe, the second pressure sensor being connected to the controller for sending air pressure data in the sampling main pipe to the controller.

4. The system of claim 3, wherein the controller is further configured to control the second electromagnetic valve and the active air extraction device to perform an automatic cleaning step according to the air pressure data in the sampling main pipe before the sampling starts.

5. The system of claim 4, wherein the automatic cleaning step comprises: the controller controls the second electromagnetic valve to be closed and the active air extraction device to continuously operate, and as ambient air continuously enters the sampling main pipe, the air pressure in the sampling main pipe gradually rises. The controller determines, according to the pressure monitoring data of the second pressure sensor, when the real-time pressure in the sampling manifold is greater than a preset pressure threshold, the controller controls the second electromagnetic valve to open, thereby instantaneously releasing gas to purge the sampling manifold.

6. The system of claim 5, wherein, The preset trigger condition comprises: The controller acquires concentration monitoring data of the target pollutant, and determines whether the real-time concentration of the target pollutant is greater than a preset target pollutant concentration threshold, if yes, the trigger condition is met.

7. The system of claim 6, wherein, The preset trigger condition further comprises: The controller acquires concentration monitoring data of the target pollutant within a preset time period, the controller arranges the concentration data of the target pollutant within the preset time period in ascending order, selects the concentration monitoring data ranked Nth as the background concentration of the target pollutant, and in the subsequent monitoring process of the target pollutant, if the concentration data of the target pollutant is greater than X times the background concentration, the trigger condition is met.

8. The system of claim 7, wherein, A one-way valve is further arranged in the sampling branch.

9. The system of claim 8, wherein, The controller is further configured to record parameters related to each sampling process, the parameters at least comprising sampling trigger time, sampling duration, trigger condition and pressure change data, and synchronously archive the concentration data of the high time resolution monitoring instrument.

Images