An automatic water vapor sampling device and automatic sampling method

Abstract

The application discloses an automatic water vapor sampling device and an automatic sampling method, which comprises a high-temperature blow-off pipe, at least one low-temperature blow-off pipe, at least one sampling assembly, a cooling and adjusting unit, a PLC control module, and the like. The cooling and adjusting unit comprises a sampling pipe, a blow-off pipe connected with the sampling pipe and connected with the high-temperature blow-off pipe, a first automatic stop valve installed on the blow-off pipe, a cooler connected with the sampling pipe through a sampling pipe, a three-way valve connected with the cooler through a first pipeline and connected with a cooling water inlet main pipe through a second pipeline, a sampling outlet connected with the cooler, and an automatic pressure reducing valve, an electromagnetic valve, a first temperature sensor and a first flow sensor which are sequentially arranged on the sampling outlet, and a second automatic stop valve is installed on the sampling pipe. The application improves the automation degree of the whole water vapor sampling device, and then sampling or automatic shutdown is carried out according to the set threshold value.

Description

Technical Field

[0001] This invention belongs to the field of sampling equipment technology, and relates to a sampling device for liquid water or water vapor media, specifically an automatic water vapor sampling device and an automatic sampling method. Background Technology

[0002] Chinese invention patent application number 202110893372.1 discloses a modular soda sampling device, which includes: a support assembly, a cooling water outlet header, a cooling water inlet header, multiple sets of installation modules, a low-temperature drainage assembly, and a sampling assembly. The sampling assembly includes a sampling plate installed on each set of installation modules. The sampling plate includes a cooperating cooling unit and an adjustment unit. The cooling unit includes a cooler detachably installed on the installation module and a three-way valve connected to the cooler and the cooling water inlet header via a first water pipe. The cooler is also connected to the cooling water outlet header via a second water pipe. The regulating unit also includes a second shut-off valve installed on the second inlet pipe and located between the second three-way pipe and the cooler, as well as a high-pressure valve connected to the second three-way pipe; the regulating unit also includes a pressure-reducing valve connected to the first inlet pipe (the pressure-reducing valve and the first inlet pipe can be connected in a conventional way, such as a three-way valve); the modular steam and water sampling device also includes a high-temperature sewage discharge header pipe connected to the high-pressure valve via a pipeline; all of the above measures can enrich the function of the regulating unit, enabling the high-temperature and high-pressure sample water to be measured and analyzed after effective cooling and pressure reduction. However, the above-mentioned steam and water sampling device relies on manual adjustment, and the degree of automation is relatively low. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to overcome the shortcomings of the prior art by providing an automatic water vapor sampling device to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: an automatic water vapor sampling device, comprising:

[0005] High-temperature sewage pipe,

[0006] At least one low-temperature drain pipe is provided, which is located below the high-temperature drain pipe.

[0007] Cooling water outlet header,

[0008] A cooling water inlet header is located below the cooling water outlet header;

[0009] At least one set of sampling components, each set of sampling components including a matching cooling adjustment unit and a functional unit;

[0010] The cooling regulation unit includes a sampling tube, a drain pipe connected to the sampling tube and the high-temperature drain pipe, a first automatic shut-off valve installed on the drain pipe, a cooler connected to the sampling tube via an inlet pipe, a three-way valve connected to the cooler via a first pipe and connected to the cooling water inlet header via a second pipe, an outlet pipe connected to the cooler, and an automatic pressure reducing valve, a solenoid valve, a first temperature sensor, and a first flow sensor installed on the outlet pipe in sequence. A second automatic shut-off valve is installed on the inlet pipe, and the cooler is also connected to the cooling water outlet header via a fourth pipe. The inlet pipe and the drain pipe are connected in parallel.

[0011] The functional unit includes a sample water distributor connected to the sample outlet pipe, a return water pipe connecting the sample water distributor and the low-temperature sewage pipe, and a measurement module connected between the sample water distributor and the low-temperature sewage pipe and in parallel with the return water pipe.

[0012] The PLC control module is connected to the first automatic shut-off valve, the second automatic shut-off valve, the automatic pressure reducing valve, the solenoid valve, the first temperature sensor, and the first flow sensor. It receives signals from the first temperature sensor to control the opening and closing of the solenoid valve and receives signals from the first flow sensor to control the opening degree of the automatic pressure reducing valve. The PLC control module is also connected to a touchscreen and communicates with the measurement module via a bus protocol through a data acquisition module. It controls the activation of the measurement module and displays the measurement data obtained by the measurement module on the touchscreen.

[0013] A second temperature sensor is installed on the high-temperature sewage pipe, and a second flow sensor and a third temperature sensor are installed on the cooling water inlet main pipe. The PLC control module is also connected to the second temperature sensor, the second flow sensor and the third temperature sensor respectively to receive signals from the second temperature sensor, the second flow sensor and the third temperature sensor, and to control the opening and closing of the first automatic shut-off valve and the second automatic shut-off valve.

[0014] Ideally, there are two low-temperature drain pipes, defined as the first low-temperature drain pipe and the second low-temperature drain pipe. The three-way valve is also connected to the second low-temperature drain pipe through a third pipeline, and the measuring module is connected to the first low-temperature drain pipe.

[0015] Optimally, the cooling regulating unit also includes a first shut-off valve installed on the fourth pipeline.

[0016] Furthermore, the cooling regulating unit also includes a filter installed on the sample outlet tube and located between the automatic pressure reducing valve and the solenoid valve.

[0017] Ideally, the sample water distributor is a back pressure type, located downstream of the first flow sensor.

[0018] Furthermore, the measurement module includes at least one of a manual sampling module, an online computational pH analyzer, an online sodium ion analyzer, and an online dissolved oxygen analyzer.

[0019] Another objective of this invention is to provide an automatic sampling method based on the aforementioned automatic water vapor sampling device, employing two start-up modes: new start-up and continuous start-up. The new start-up includes the following steps:

[0020] (a) Close the automatic pressure reducing valve to its minimum opening;

[0021] (b) Read the temperature value of the second temperature sensor: When the temperature value of the second temperature sensor is ≤150℃, determine whether the first automatic shut-off valve is open. If the first automatic shut-off valve is not open, it is inspected; when the temperature value of the second temperature sensor is >150℃, the first automatic shut-off valve is opened for a certain period of time and then automatically closed.

[0022] (c) Read the values ​​of the first temperature sensor, the second flow sensor and the third temperature sensor. When the temperature value of the first temperature sensor is <45℃, the flow value of the second flow sensor is ≥10t / h and the temperature value of the third temperature sensor is ≤40℃, the PLC control module controls the opening of the solenoid valve and the second automatic shut-off valve respectively.

[0023] (d) The opening of the automatic pressure reducing valve is adjusted to a specific flow rate using the PLC control module. When the pressure reducing valve increases the flow rate, the excess sample water medium flow rate is discharged through the overflow pipe of the back pressure valve, thereby ensuring the stability of the sample water pipe pressure, and vice versa.

[0024] (e) Read the flow rate value of the first flow sensor. When the flow rate value of the first flow sensor is >20L / h, start the measurement module to perform sampling analysis test.

[0025] (f) For shutdowns caused by unexpected situations such as power outages, low flow rates, or maintenance, the system can be restarted quickly by skipping steps (a) and (b).

[0026] Ideally, in steps (b) and (c), the judgment values ​​of each temperature and flow sensor can be set within a certain range.

[0027] Ideally, in step (b), the first automatic shut-off valve is opened for a period of 3 to 60 minutes.

[0028] Ideally, in step (d), the opening degree of the automatic pressure reducing valve is 10-100 L / h, preferably 60 L / h.

[0029] Further, in step (d), the automatic pressure reducing valve is adjusted periodically within a flow range of 10-100 L / h, and the pipeline is judged to be leaking based on the effect of the flow rate change on the instrument measurement value.

[0030] The automatic water vapor sampling device of the present invention, by installing cooling adjustment units, functional units, PLC control modules and other structures on the high temperature drain pipe, low temperature drain pipe, cooling water outlet main pipe, cooling water inlet main pipe, sampling components and other structures, can automatically control the opening and closing of the first automatic shut-off valve, the second automatic shut-off valve and the solenoid valve, and automatically control the opening degree of the automatic pressure reducing valve, thereby improving the automation level of the entire water vapor sampling device, and then sampling or automatically stopping according to the set threshold. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the automatic water vapor sampling device of the present invention;

[0032] Figure 2 This is a flowchart of the automatic sampling method of the automatic water vapor sampling device of the present invention. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail.

[0034] The foregoing descriptions and other technical contents, features, and effects of this invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms used in the following embodiments, such as up, down, left, right, front, or back, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0035] like Figure 1 The automatic water vapor sampling device shown includes a high-temperature drain pipe 1, a low-temperature drain pipe, a cooling water outlet main pipe 2, a cooling water inlet main pipe 3, at least one set of sampling components 6, and a PLC control module.

[0036] There is at least one low-temperature drain pipe, which is located below the high-temperature drain pipe 1. The cooling water inlet header 3 is located below the cooling water outlet header 2. The high-temperature drain pipe 1 is usually located above the cooling water outlet header 2 and slightly higher than it. The low-temperature drain pipe is slightly higher than the cooling water inlet header 3. In this embodiment, there are two low-temperature drain pipes, namely the first low-temperature drain pipe 4 and the second low-temperature drain pipe 5 (a safety valve is also connected between the first low-temperature drain pipe 4 and the cooling water inlet header 3. If the cooler 611 is damaged, the high-temperature sample water or steam will directly enter the cooling water, which will increase the cooling water pressure. Therefore, a safety valve is added to ensure the safety of the entire automatic water vapor sampling device).

[0037] There is at least one set of sampling components 6, and the specific number can be determined according to actual needs; when there are multiple sets of sampling components 6, they can be connected in parallel and cooperate with the aforementioned pipes. Each set of sampling components 6 includes a cooperating cooling adjustment unit 61 and a functional unit 63.

[0038] The cooling regulating unit 61 includes a sampling pipe 6110 connected to the sampling point, a drain pipe 6113 connected to the sampling pipe 6110 and connected to the high-temperature drain pipe 1, a first automatic shut-off valve 6114 installed on the drain pipe 6113, a cooler 611 connected to the sampling pipe 6110 via an inlet pipe 6111 (at this time, the inlet pipe 6111 and the drain pipe 6113 are connected in parallel), and a cooling water inlet header 3 connected to the cooler 611 via a first pipe 612 and a second pipe 6141. The system includes a three-way valve 614, a sample outlet pipe 6112 connected to the cooler 611, and an automatic pressure reducing valve 616, a solenoid valve 618, a first temperature sensor 619, and a first flow sensor 620 installed sequentially on the sample outlet pipe 6112 (these sequential arrangements are defined according to the flow direction of the sample water; the first flow sensor 620 is downstream of the automatic pressure reducing valve 616, making it furthest from the cooler 611 while the automatic pressure reducing valve 616 is closest to the cooler 611). A second automatic shut-off valve 610 is installed on the sample inlet pipe 611, positioned upstream of the cooler 611. The cooler 611 is also connected to the cooling water outlet header 2 via a fourth pipe 613, allowing cooling water to be discharged into the cooling water outlet header 2 after heat exchange in the cooler 611.

[0039] In this embodiment, the three-way valve 614 is also connected to the second low-temperature drain pipe 5 via the third pipe 6142. This ensures that the three-way valve 614 does not shut off the cooler 611. When the three-way valve 614 closes the second pipe 6141, the third pipe 6142 connects to the cooler 611, and the coolant from the cooler is discharged into the second low-temperature drain pipe 5. The cooling regulating unit 61 also includes a first shut-off valve 615 installed on the fourth pipe 613. This valve is typically manual and normally open, facilitating maintenance of the entire automatic water vapor sampling device. The cooling regulating unit 61 also includes a filter 617 installed on the sample outlet pipe 6112 and located between the automatic pressure reducing valve 616 and the solenoid valve 618, used to filter the sample water to prevent clogging.

[0040] Functional unit 63 includes a sample water distributor 631 connected to the sample outlet pipe 6112, a return water pipe 632 connecting the sample water distributor 631 and the low-temperature drain pipe (the return water pipe 632 allows the sample water in the cooler 611 to be discharged into the first low-temperature drain pipe 4 after heat exchange), and a measurement module connected between the sample water distributor 631 and the low-temperature drain pipe and in parallel with the return water pipe 632 (for measuring the sample water after heat exchange); the measurement module is connected to the first low-temperature drain pipe 4 (i.e., the measured sample water is discharged into the first low-temperature drain pipe 4). The sample water distributor 631 is a back pressure type and is located downstream of the first flow sensor 620. The measurement module includes at least one of a manual sampling module 637, an online calculation-type pH analyzer 638, an online sodium ion analyzer 639, and an online dissolved oxygen analyzer 630; in this application, the measurement module typically includes all of the above-mentioned functional devices.

[0041] The PLC control module 7 is connected to the first automatic shut-off valve 6114, the second automatic shut-off valve 610, the automatic pressure reducing valve 616, the solenoid valve 618, the first temperature sensor 619, and the first flow sensor 620, respectively, to receive signals from the first temperature sensor 619 and the first flow sensor 620, and to control the opening and closing (i.e., switching) of the solenoid valve 618 and the opening degree of the automatic pressure reducing valve 616, respectively. The PLC control module 7 is also connected to the touch screen 9 and communicates with the measurement module via the data acquisition module 8 using a bus protocol, to control the start of the measurement module and display the measurement data obtained by the measurement module on the touch screen 9.

[0042] In this embodiment, a second temperature sensor 11 is installed on the high-temperature drain pipe 1, and a second flow sensor 31 and a third temperature sensor 32 are installed on the cooling water inlet main pipe 3. The PLC control module 7 is also connected to the second temperature sensor 11, the second flow sensor 31 and the third temperature sensor 32 respectively to receive the signals from the second temperature sensor 11, the second flow sensor 31 and the third temperature sensor 32, and to control the opening and closing of the first automatic shut-off valve 6114 and the second automatic shut-off valve 610.

[0043] Specifically, when the first automatic shut-off valve 6114 is closed, the second automatic shut-off valve 610 opens, or the second automatic shut-off valve 610 opens under the following conditions: 1. When the first temperature sensor 619 detects that the sample water temperature is <45℃; 2. When the second flow sensor 31 detects that the sample water flow rate is ≥10t / h (which can be selected as needed); 3. When the third temperature sensor 32 detects that the cooling water temperature is <40℃. The opening of the first automatic shut-off valve 6114 can be detected by the temperature data from the second temperature sensor 11 (the first automatic shut-off valve 6114 is usually closed, but can be scheduled to open for timed drainage, such as every Monday at 24:00, with a drainage time of 20-30 minutes).

[0044] The automatic pressure reducing valve 616 can be closed first (i.e., when the automatic water vapor sampling device is started). After the sewage discharge is completed and the second automatic shut-off valve 610 is opened, the automatic pressure reducing valve 616 opens to 60L / h (the specific flow rate can be set as needed), and then the flow rate is controlled at the set flow rate through the flow feedback signal of the first flow sensor 620. The data acquisition module 8 transmits the measured values ​​of the measurement module to the PLC control module via the bus protocol and displays them on the touch screen 9 (the starting condition of the measurement module is: the flow rate measured by the flow meter is 20L / h, which can be set as needed).

[0045] The PLC control module 7 can be commercially available, such as those disclosed in Chinese invention patent application number 201711047190.2, Chinese invention patent application number 201910582341.7, or Chinese utility model patent application number 201921007341.6 (corresponding to the processor). Furthermore, corresponding control thresholds can be set based on these modules according to specific requirements; or the module can be designed and developed according to the design concept of the 2000 coal-fired demonstration power plant proposed by the China Electric Power Planning & Engineering Institute, based on the control requirements.

[0046] Based on the automatic sampling method of the above-mentioned water vapor sampling device, the new start-up includes the following steps (the water vapor sampling device can adopt two start-up methods: new start-up and continuous start-up):

[0047] (a) Turn on the power to the entire water vapor sampling device and start it up, and close the automatic pressure reducing valve 616 to the minimum opening;

[0048] (b) Read the temperature value of the second temperature sensor 11: When the temperature value of the second temperature sensor 11 is ≤150℃ (this threshold can be modified to 100~500℃ according to the actual application needs), determine whether the first automatic shut-off valve 6114 is open. If the first automatic shut-off valve 6114 is not open, it needs to be manually inspected; when the temperature value of the second temperature sensor 11 is >150℃, the first automatic shut-off valve 6114 is opened for a certain period of time and then automatically closed; specifically, the time for the first automatic shut-off valve 6114 to open is 3~60 minutes, and in this embodiment it is 5 minutes, so as to realize timed opening and automatic sewage discharge;

[0049] (c) Read the values ​​of the first temperature sensor 619, the second flow sensor 31 and the third temperature sensor 32. When the temperature value of the first temperature sensor 619 is <45℃, the flow value of the second flow sensor 31 is ≥10t / h and the temperature value of the third temperature sensor 32 is ≤40℃ (the above parameters can be adjusted according to actual needs), the PLC control module 7 controls the opening of the solenoid valve 618 and the second automatic shut-off valve 610 respectively; otherwise, the machine stops. In steps (b) and (c), the judgment values ​​of each temperature and flow sensor can be set within a certain range as needed.

[0050] (d) Use the PLC control module 7 to adjust the opening of the automatic pressure reducing valve 616 to a specific flow rate; the opening of the automatic pressure reducing valve 616 is 10-100 L / h, and in this embodiment it is 60 L / h; note that the automatic pressure reducing valve 616 needs to be adjusted periodically within the flow range of 10-100 L / h, and the influence of the flow rate change on the instrument readings should be used to determine whether there is an air leak in the pipeline. When the pressure reducing valve 616 increases the flow rate, the excess sample water medium flow is discharged through the overflow pipe 632 of the back pressure valve 631, thereby ensuring the pressure of the sample water pipe 6112 is stable, and vice versa.

[0051] (e) Read the flow value of the first flow sensor 620. When the flow value of the first flow sensor 620 is >20L / h, start the measurement module to perform sampling analysis test; otherwise, stop the machine.

[0052] (f) For shutdowns caused by unexpected situations such as power outages, low flow rates, or maintenance, the system can be restarted quickly by skipping steps (a) and (b).

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An automatic sampling method, based on an automatic water vapor sampling device, the automatic water vapor sampling device comprising: High-temperature sewage pipe (1). At least one low-temperature drain pipe is provided, which is located below the high-temperature drain pipe (1). Cooling water outlet header (2). Cooling water inlet header (3), which is located below the cooling water outlet header (2); At least one set of sampling components (6), each set of sampling components (6) includes a matching cooling adjustment unit (61) and a functional unit (63). The cooling regulating unit (61) includes a sampling tube (6110), a drain pipe (6113) connected to the sampling tube (6110) and connected to the high-temperature drain pipe (1), a first automatic shut-off valve (6114) installed on the drain pipe (6113), a cooler (611) connected to the sampling tube (6110) through an inlet pipe (6111), and a three-way valve (614) connected to the cooler (611) through a first pipeline (612). The three-way valve (614) is also connected to the cooling water inlet header (3) through a second pipeline (6141). The cooling regulating unit (61) further includes a sample outlet pipe (6112) connected to the cooler (611) and an automatic pressure reducing valve (616), a solenoid valve (618), a first temperature sensor (619), and a first flow sensor (620) installed on the sample outlet pipe (6112). The automatic pressure reducing valve (616), the solenoid valve (618), the first temperature sensor (619), and the first flow sensor (620) are arranged in sequence. A second automatic shut-off valve (610) is installed on the sample inlet pipe (6111). The cooler (611) is also connected to the cooling water outlet header (2) through a fourth pipeline (613). The sample inlet pipe (6111) is connected in parallel with the drain pipe (6113). The functional unit (63) includes a sample water distributor (631) connected to the sample outlet pipe (6112), a return water pipe (632) connecting the sample water distributor (631) and the low temperature drain pipe, and a measurement module connected between the sample water distributor (631) and the low temperature drain pipe and in parallel with the return water pipe (632). The PLC control module (7) is connected to the first automatic shut-off valve (6114), the second automatic shut-off valve (610), the automatic pressure reducing valve (616), the solenoid valve (618), the first temperature sensor (619), and the first flow sensor (620) respectively. It receives the signal from the first temperature sensor (619) to control the opening and closing of the solenoid valve (618), and receives the signal from the first flow sensor (620) to control the opening degree of the automatic pressure reducing valve (616). The PLC control module (7) is also connected to a touch screen (9) and communicates with the measurement module via a bus protocol through a data acquisition module (8). It is used to control the start of the measurement module and display the measurement data obtained by the measurement module on the touch screen (9). A second temperature sensor (11) is installed on the high-temperature sewage pipe (1), and a second flow sensor (31) and a third temperature sensor (32) are installed on the cooling water inlet main pipe (3); the PLC control module (7) is also connected to the second temperature sensor (11), the second flow sensor (31) and the third temperature sensor (32) respectively, so as to receive the signals of the second temperature sensor (11), the second flow sensor (31) and the third temperature sensor (32) to control the opening and closing of the first automatic shut-off valve (6114) and the second automatic shut-off valve (610); Its characteristic is that it adopts two startup methods: new startup and continuous startup. The new startup includes the following steps: (a) Close the automatic pressure reducing valve (616) to its minimum opening; (b) Read the temperature value of the second temperature sensor (11): When the temperature value of the second temperature sensor (11) is ≤150℃, determine whether the first automatic shut-off valve (6114) is open. If the first automatic shut-off valve (6114) is not open, it is inspected; when the temperature value of the second temperature sensor (11) is >150℃, the first automatic shut-off valve (6114) is opened for a certain period of time and then automatically closed. (c) Read the values ​​of the first temperature sensor (619), the second flow sensor (31) and the third temperature sensor (32). When the temperature value of the first temperature sensor (619) is <45℃, the flow value of the second flow sensor (31) is ≥10t / h and the temperature value of the third temperature sensor (32) is ≤40℃, the PLC control module (7) controls the opening of the solenoid valve (618) and the second automatic shut-off valve (610) respectively. (d) The opening of the automatic pressure reducing valve (616) is adjusted to a specific flow rate using the PLC control module (7). When the pressure reducing valve (616) increases the flow rate, the excess sample water medium flow rate is discharged through the return water pipe (632) of the sample water distributor (631), thereby ensuring the stability of the pressure of the sample outlet pipe (6112), and vice versa. (e) Read the flow value of the first flow sensor (620). When the flow value of the first flow sensor (620) is >20L / h, start the measurement module to perform sampling analysis test. (f) For shutdowns caused by unforeseen circumstances, the option to skip steps (a) and (b) can be selected for quick restart.

2. The automated sampling method of claim 1, wherein: There are two low-temperature drain pipes, defined as the first low-temperature drain pipe (4) and the second low-temperature drain pipe (5). The three-way valve (614) is also connected to the second low-temperature drain pipe (5) through a third pipeline (6142). The measuring module is connected to the first low-temperature drain pipe (4).

3. The automated sampling method of claim 1, wherein: The cooling regulating unit (61) also includes a first shut-off valve (615) installed on the fourth pipeline (613).

4. The automated sampling method of claim 1 or 3, wherein: The cooling regulating unit (61) also includes a filter (617) installed on the sample outlet tube (6112) and located between the automatic pressure reducing valve (616) and the solenoid valve (618).

5. The automatic sampling method according to claim 1, characterized in that: The sample water distributor (631) is a back pressure type and is located downstream of the first flow sensor (620).

6. The automated sampling method of claim 1 or 5, wherein: The measurement module includes at least one of a manual sampling module (637), an online calculation pH analyzer (638), an online sodium ion analyzer (639), and an online dissolved oxygen analyzer (630).

7. The automated sampling method of claim 1, wherein: In step (b), the first automatic shut-off valve (6114) is opened for a period of 3 to 60 minutes.

8. The automated sampling method of claim 1, wherein: In step (d), the opening degree of the automatic pressure reducing valve (616) is 10~100L / h.

9. The automated sampling method of claim 8, wherein: In step (d), the opening degree of the automatic pressure reducing valve (616) is 60L / h.

10. The automatic sampling method according to claim 8, characterized in that: In step (d), the automatic pressure reducing valve (616) is adjusted periodically within a flow range of 10-100 L / h, and the pipeline is judged to be leaking based on the effect of the flow change on the instrument measurement.

11. The automated sampling method of claim 1, wherein: In steps (b) and (c), the judgment values ​​of each temperature sensor and flow sensor can be set within a certain range.

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