Flue gas circulating sampling and measuring device

Abstract

The utility model relates to the technical field of gas detection, and discloses a flue gas circulation sampling and measuring device which comprises a sampling assembly, a heat preservation cavity and a measuring assembly. The sampling assembly comprises a sampling pipe, the sampling pipe is arranged on the cavity wall of the cavity to be detected, and smoke circulates in the cavity to be detected. The heat preservation cavity is located outside the to-be-detected cavity and comprises a first cavity and a second cavity which are communicated through a circulating fan, the sampling pipe comprises an air inlet pipe and an air return pipe, the air inlet pipe is communicated with the to-be-detected cavity and the first cavity, and the air return pipe is communicated with the second cavity and the to-be-detected cavity. The circulating fan is used for enabling flue gas in the to-be-measured cavity to sequentially flow through the gas inlet pipe, the first cavity and the second cavity and flow back to the to-be-measured cavity through the gas return pipe, the measuring assembly is partially arranged in the first cavity, and the measuring assembly can be used for measuring specified indexes of the flue gas flowing through the first cavity. The flue gas circular sampling and measuring device can perform circular sampling, does not discharge any gas and solid waste, avoids environmental pollution, and is accurate in measuring result.

Description

Technical Field

[0001] The utility model relates to the technical field of gas detection, in particular to a flue gas circulation sampling and measuring device. Background Art

[0002] Generally, flue gas parameter measurement devices can be divided into two categories: in-smoke measurement and extraction measurement. The former requires the sensor to be placed in the flue for operation, while the latter requires the flue gas to be extracted outside the flue for measurement. For the online measurement of the acid dew point temperature in high-temperature dusty flue gas at around 300°C, according to the use practice of existing measurement equipment, the cooling capacity of the sensor measurement surface is insufficient due to the performance of the cooling medium, and the in-smoke measurement method often fails to meet the requirements. There are several problems with the currently reported extractive acid dew point temperature measurement method: 1. The flue gas is filtered and treated, which will cause the measured acid dew point temperature to be distorted, because the dust in the flue gas is one of the main factors affecting the acid dew point temperature; 2. The acid dew point temperature is estimated by measuring some flue gas components, which is similar to the above, that is, some influencing factors may be omitted and cause data deviation; 3. The measuring device is often some distance away from the sampling tube, requiring a high-temperature resistant connecting pipe and heating insulation; 4. The measurement process is often open-loop, that is, the extracted flue gas is discharged after treatment, but it is also accompanied by the discharge of waste from the flue gas treatment.

[0003] Therefore, there is an urgent need for a flue gas circulation sampling and measuring device to solve the above problems. Utility Model Content

[0004] The utility model aims to provide a flue gas circulation sampling and measuring device, which has accurate detection results and can realize closed-loop sampling without any gas or solid waste discharge, thus avoiding environmental pollution.

[0005] As conceived above, the technical solution adopted by the utility model is:

[0006] Flue gas circulation sampling and measuring device, including:

[0007] The sampling assembly comprises a sampling tube, wherein the sampling tube is arranged on the cavity wall of the cavity to be tested, smoke flows in the cavity to be tested, and the sampling tube comprises an air inlet pipe and an air return pipe;

[0008] A heat preservation chamber is located outside the chamber to be tested, the heat preservation chamber includes a first chamber and a second chamber connected by a circulating fan, the first chamber is connected to the chamber to be tested through the air inlet pipe, and the second chamber is connected to the chamber to be tested through the air return pipe; the circulating fan is used to enable the smoke in the chamber to be tested to flow through the air inlet pipe, the first chamber, and the second chamber in sequence, and to flow back to the chamber to be tested through the air return pipe; the temperature in the heat preservation chamber is higher than a first preset temperature;

[0009] A measuring component is partially disposed in the first cavity, and is used to measure a specified index of the smoke flowing through the first cavity.

[0010] Optionally, the sampling assembly further includes an isolation plate, wherein the isolation plate, the air inlet of the air inlet pipe and the air return port of the air return pipe are all located in the chamber to be tested, and the isolation plate is arranged between the air inlet and the air return port.

[0011] Optionally, the sampling assembly also includes a protective tube, which is inserted into the wall of the cavity to be tested, and the isolation plate is arranged in the protective tube. The isolation plate is used to separate the protective tube into a first tube and a second tube. An air outlet is arranged on the side wall of the second tube, and the return air pipe is located in the second tube. The air outlet is connected to the return air port, and the air inlet pipe is passed through the return air pipe, and the air inlet extends into the first tube.

[0012] Optionally, the smoke flowing in the chamber to be tested has a preset flow direction, and the air inlet and the port of the protection tube located in the chamber to be tested are both inclined structures that gradually incline toward one side of the return air pipe in the preset flow direction.

[0013] Optionally, the smoke flowing in the chamber to be tested has a preset flow direction, and the air outlet is arranged on the leeward side of the protection tube.

[0014] Optionally, the flue gas circulation sampling and measuring device also includes a purge assembly, which includes a first purge tube and a second purge tube, wherein the first purge tube is connected to the first cavity and is used to introduce gas of a first temperature into the cavity to be measured, and the second purge tube is connected to the second cavity and is used to introduce gas of a second temperature into the cavity to be measured.

[0015] Optionally, a first control valve is provided on the first purge pipe, and the inlet of the first purge pipe is connected to the outlet of the first purge pipe through the first control valve;

[0016] The second purge pipe is provided with a second control valve, and the inlet of the second purge pipe is connected with the outlet of the second purge pipe through the second control valve.

[0017] Optionally, the flue gas circulation sampling and measuring device further comprises a motor, and an output shaft of the motor is connected to the circulation fan.

[0018] Optionally, an outer wall of the heat preservation chamber is provided with a heat preservation layer.

[0019] Optionally, the measuring component is an acid dew point temperature measuring mechanism, and the acid dew point temperature measuring mechanism is used to measure the acid dew point temperature of the flue gas in the first cavity.

[0020] The beneficial effects of the utility model are:

[0021] The smoke circulation sampling and measuring device proposed in the utility model comprises a sampling component, a heat preservation chamber and a measuring component. The sampling component comprises a sampling tube, which is arranged on the cavity wall of the cavity to be measured, and smoke flows in the cavity to be measured. The heat preservation chamber is located outside the cavity to be measured, and the temperature in the heat preservation chamber is higher than the first preset temperature. The heat preservation chamber and the cavity to be measured are connected through the sampling tube, and the smoke in the cavity to be measured can enter the heat preservation chamber. The length of the sampling tube between the cavity to be measured and the heat preservation chamber can be shortened, and the heat preservation chamber can be made close to the cavity to be measured to avoid the smoke in the cavity to be measured from losing temperature during the process of entering the heat preservation chamber. The heat preservation chamber comprises a first cavity and a second cavity, and the first cavity and the second cavity are connected through a circulation fan. The sampling tube comprises an air inlet pipe and an air return pipe, and the air inlet pipe is used to connect the cavity to be measured with the first cavity, and the air return pipe is used to connect the second cavity with the cavity to be measured. The circulation fan is used to enable the smoke in the cavity to be measured to flow through the air inlet pipe, the first cavity, and the second cavity in sequence, and to flow back to the cavity to be measured through the air return pipe. The measuring component is partially disposed in the first cavity, and the measuring component can be used to detect the designated index of the flue gas flowing through the first cavity. The detected flue gas can also be drawn from the first cavity to the second cavity by the circulating fan, and then flow back to the cavity to be measured through the return air pipe. The flue gas circulation sampling and measuring device does not use a filtering mechanism to filter the flue gas drawn from the cavity to be measured, which can avoid the influence of the filtered flue gas components on the measurement accuracy of the flue gas. The flue gas in the cavity to be measured is circulated and extracted, so that the concentration of the flue gas components drawn into the first cavity tends to be consistent with the concentration of the flue gas components in the cavity to be measured, thereby improving the accuracy of the measurement results of the flue gas in the cavity to be measured. In addition, after the flue gas in the first cavity is measured, the flue gas can still flow back to the cavity to be measured without any gaseous or solid waste emissions, and there is no need to set up a waste gas treatment mechanism, which can avoid pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a flue gas circulation sampling and measuring device provided in an embodiment of the utility model.

[0023] In the figure:

[0024] 1. Sampling assembly; 11. Air inlet pipe; 111. Air inlet port; 12. Air return pipe; 121. Air return port; 13. Protection tube; 131. First tube; 1311. Port; 132. Second tube; 1321. Air outlet port; 14. Isolation sheet;

[0025] 2. Insulation chamber; 21. First chamber; 22. Second chamber; 23. Insulation layer; 24. Partition plate;

[0026] 3. Purge assembly; 31. Purge pipe 1; 311. First control valve; 32. Purge pipe 2; 321. Second control valve;

[0027] 4. Circulation fan; 5. Motor; 6. Measuring component;

[0028] 100. Cavity to be tested. DETAILED DESCRIPTION

[0029] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of them.

[0030] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0032] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0033] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0034] like Figure 1As shown, this embodiment provides a flue gas circulation sampling and measuring device, including a sampling component 1, a heat preservation chamber 2 and a measuring component 6. The sampling component 1 includes a sampling tube, which is arranged on the cavity wall of the cavity to be measured 100, and flue gas flows in the cavity to be measured 100. The heat preservation chamber 2 is located outside the cavity to be measured 100, and the temperature in the heat preservation chamber 2 is higher than the first preset temperature. The heat preservation chamber 2 and the cavity to be measured 100 are connected through the sampling tube, and the flue gas in the cavity to be measured 100 can enter the heat preservation chamber 2. By shortening the length of the sampling tube between the cavity to be measured 100 and the heat preservation chamber 2, the heat preservation chamber 2 can be brought close to the cavity to be measured 100, so as to avoid the flue gas in the cavity to be measured 100 from losing temperature in the process of entering the heat preservation chamber 2. Specifically, the heat preservation chamber 2 includes a first chamber 21 and a second chamber 22, which are connected through a circulation fan 4, and the sampling tube includes an air inlet pipe 11 and an air return pipe 12. The air inlet pipe 11 is used to connect the chamber to be tested 100 and the first chamber 21, and the air return pipe 12 is used to connect the chamber to be tested 100 and the second chamber 22. The circulation fan 4 can make the smoke in the chamber to be tested 100 flow through the air inlet pipe 11, the first chamber 21, and the second chamber 22 in sequence, and return to the chamber to be tested 100 through the air return pipe 12. The measuring component 6 is partially arranged in the first chamber 21, and the measuring component 6 can be used to detect the specified index of the smoke flowing through the first chamber 21. The detected smoke can also be extracted from the first chamber 21 to the second chamber 22 by the circulation fan 4, and then return to the chamber to be tested 100 through the air return pipe 12. The flue gas circulation sampling and measuring device provided in the present embodiment does not use a filtering mechanism to filter the flue gas, which can avoid the influence of the filtered flue gas components on the measurement accuracy of the flue gas. The flue gas in the chamber to be measured 100 is circulated and extracted, so that the concentration of the flue gas components sucked into the first chamber 21 and the concentration of the flue gas components in the chamber to be measured 100 tend to be consistent, thereby improving the accuracy of the flue gas measurement results. In addition, after the flue gas is measured, the flue gas in the first chamber 21 can still flow back to the chamber to be measured 100 without any gaseous or solid waste emissions, and there is no need to set up a waste gas treatment mechanism, which can avoid pollution to the environment. The flue gas circulation sampling and measuring device provided in the present embodiment can be used for measuring the acid dew point temperature of the flue gas. The first preset temperature is higher than the acid dew point temperature of the flue gas to avoid condensation of the flue gas after entering the insulation chamber 2, thereby affecting the measurement results. The first preset temperature may be much higher than the acid dew point temperature of the flue gas. Therefore, before the acid dew point temperature of the flue gas is accurately measured, it can be ensured that the first preset temperature is higher than the acid dew point temperature of the flue gas in the measurement chamber 100 .

[0035] In a specific implementation, a partition plate 24 is further provided in the heat preservation chamber 2 , and the partition plate 24 divides the heat preservation chamber 2 into a first chamber 21 and a second chamber 22 . The circulation fan 4 is provided on the partition plate 24 .

[0036] Preferably, the flue gas circulation sampling and measuring device further comprises a motor 5 , the output shaft of the motor 5 is connected to the circulation fan 4 , and the motor 5 is used to drive the circulation fan 4 to rotate.

[0037] Optionally, the sampling assembly 1 further includes an isolation sheet 14, and the isolation sheet 14, the air inlet 111 of the air inlet pipe 11, and the air return port 121 of the air return pipe 12 are all located in the chamber to be measured 100, and the isolation sheet 14 is arranged between the air inlet 111 and the air return port 121. The arrangement of the isolation sheet 14 can prevent the smoke that flows back into the chamber to be measured 100 through the air return pipe 12 from being immediately sent to the first chamber 21 through the air inlet pipe 11 for measurement, and prevent the smoke that has just been discharged from the second chamber 22 from being repeatedly sampled, which results in a reduction in the accuracy of the measurement result of the specified index of the smoke in the chamber to be measured 100. In this embodiment, the flue gas circulation sampling and measuring device can be used to measure the acid dew point temperature of the flue gas. The condensation temperature of sulfuric acid vapor in the flue gas is the acid dew point temperature. During the circulation sampling and measuring process, due to the condensation of sulfuric acid vapor, the concentration of the flue gas downstream of the measuring component 6 is lower than the concentration of the flue gas upstream of the measuring component 6. Therefore, if the flue gas discharged through the second chamber 22 is directly extracted into the first chamber 21, the concentration of the flue gas in the first chamber 21 will be different from the concentration of the flue gas circulating in the chamber 100 to be measured.

[0038] Optionally, the sampling assembly 1 also includes a protective tube 13, which is inserted into the cavity wall of the cavity 100 to be tested, and an isolation plate 14 is arranged in the protective tube 13, and the isolation plate 14 is used to separate the protective tube 13 into a first tube 131 and a second tube 132. A gas outlet 1321 is arranged on the side wall of the second tube 132, and the return air pipe 12 is located in the second tube 132, and the gas outlet 1321 is connected to the return air port 121, and the air inlet pipe 11 is passed through the return air pipe 12, and the air inlet 111 extends into the first tube 131, that is, the air inlet 111 is arranged at the end of the sampling assembly 1, and the return air port 121 is arranged in the middle of the sampling assembly 1. Under this setting, the return air pipe 12 can be used to insulate the air intake pipe 11, which can prevent the rapid cooling of the portion of the air intake pipe 11 outside the chamber 100 to be tested, and the insulation chamber 2 is directly connected to the sampling tube, which can prevent the flue gas temperature in the sampling tube from rapidly decreasing due to the long sampling tube being outside the chamber 100 to be tested, thereby affecting the measurement results of the specified index of the flue gas in the chamber 100 to be tested. The flue gas circulation sampling and measurement device provided in this embodiment can be used for measuring the acid dew point temperature of flue gas. The structural setting of the sampling tube and the insulation chamber 2 can ensure the insulation effect of the sampled flue gas, and prevent the high-temperature flue gas sampled from dissipating heat and cooling during the sampling process to produce condensation.

[0039] Preferably, an insulation layer 23 is provided on the outer wall of the insulation chamber 2. In this embodiment, the insulation chamber 2 is used to prevent the high-temperature flue gas from being at an ambient temperature below the acid dew point temperature of the flue gas after entering the insulation chamber 2, thereby affecting the measurement result of the acid dew point temperature of the flue gas. In addition, the provision of the insulation layer 23 can also reduce the heating demand for the insulation chamber 2, which is more energy-saving.

[0040] Preferably, the measuring component 6 is an acid dew point temperature measuring mechanism, which is used to measure the acid dew point temperature of the flue gas flowing through the first chamber 21. In specific implementation, the flue gas in the chamber 100 to be measured is high-temperature dusty flue gas. The flue gas enters the first chamber 21, and the measuring surface of the acid dew point temperature measuring mechanism is cooled so that the flue gas flowing through the measuring surface can produce condensation on the measuring surface, thereby measuring the acid dew point temperature of the flue gas. After the measurement is completed, the temperature of the measuring surface of the acid dew point temperature measuring mechanism rises so that the condensation condensed thereon evaporates and can flow back to the chamber 100 to be measured through the return air pipe 12.

[0041] Optionally, the flue gas flowing in the chamber to be tested 100 has a preset flow direction, that is, the flue gas flows in the chamber to be tested 100, and the protective tube 13 is inserted on the side wall of the chamber to be tested 100, then a part of the outer peripheral surface of the protective tube 13 is the windward surface, and another part of the outer peripheral surface of the protective tube 13 is the leeward surface. In order to reduce the dust in the flue gas entering the air inlet 111 during the sampling process, it is necessary to avoid setting the port 1311 of the protective tube 13 on the windward surface, and avoid setting the air inlet 111 of the air inlet pipe 11 outside the protective tube 13, that is, the air inlet pipe 11 does not extend out of the protective tube 13. In this embodiment, the air inlet 111 and the port 1311 of the protective tube 13 located in the chamber to be tested 100 are both inclined structures that gradually tilt toward the side of the return air pipe 12 in the preset flow direction, thereby further reducing the dust entering the protective tube 13 and the air inlet pipe 11. Figure 1 The arrow in the figure indicates the flow direction of the smoke in the chamber 100 to be tested in this example.

[0042] Optionally, the flue gas flowing in the chamber 100 to be measured has a preset flow direction, and a portion of the outer peripheral surface of the protection tube 13 is the windward side, and another portion of the outer peripheral surface of the protection tube 13 is the leeward side, and the air outlet 1321 is arranged on the leeward side of the protection tube 13. The flue gas circulation sampling and measuring device provided in this embodiment can be used for measuring the acid dew point temperature of flue gas, and arranging the air outlet 1321 on the leeward side can reduce the dust in the flue gas from entering the protection tube 13 and the return air pipe 12.

[0043] Further, the flue gas circulation sampling and measuring device also includes a purge assembly 3, which includes a purge tube 1 31 and a purge tube 2 32. The purge tube 1 31 is connected to the first cavity 21, and the gas at the first temperature can enter the cavity 100 to be measured through the purge tube 31 through the first cavity 21, while the purge tube 2 32 is connected to the second cavity 22, and the gas at the second temperature can enter the cavity 100 to be measured through the purge tube 32 through the second cavity 22. In this embodiment, in order to measure the acid dew point temperature of the flue gas, the first temperature and the second temperature are both higher than the acid dew point temperature of the flue gas to avoid affecting the measurement result of the acid dew point temperature of the flue gas. In specific implementation, the first temperature and the second temperature can be much higher than the acid dew point temperature of the flue gas, so before the acid dew point temperature of the flue gas is accurately measured, it can also be ensured that the temperature of the gas in the purge tube 1 31 and the purge tube 2 32 is higher than the acid dew point temperature of the flue gas in the cavity 100 to be measured. Preferably, flue gas consistent with that in the chamber to be tested 100 is introduced into the first purge tube 31 and the second purge tube 32, and the flow direction of the flue gas in the first purge tube 31 and the second purge tube 32 is from the heat preservation chamber 2 to the chamber to be tested 100, so as to blow the dust deposited in the heat preservation chamber 2 back to the chamber to be tested 100. The flow rate of the gas in the purge assembly 3 is relatively large to ensure that even if the circulating fan 4 is in working state, the gas in the purge assembly 3 can still flow to the chamber to be tested 100 through the air inlet pipe 11 or the air return pipe 12. In specific implementation, the purge assembly 3 works intermittently, that is, only when it is necessary to purge the dust in the heat preservation chamber 2, gas is introduced into the first chamber 21 through the first purge tube 31, and gas is introduced into the second chamber 22 through the second purge tube 32.

[0044] Preferably, a first control valve 311 is provided on the purge tube 31, and the inlet of the purge tube 31 is connected to the outlet of the purge tube 31 through the first control valve 311. In specific implementation, the inlet of the purge tube 31 is located in the first chamber 21, and the outlet of the purge tube 31 and the first control valve 311 are both located outside the heat preservation chamber 2.

[0045] Preferably, the second purge tube 32 is provided with a second control valve 321, and the inlet of the second purge tube 32 is connected to the outlet of the second purge tube 32 through the second control valve 321. In specific implementation, the inlet of the second purge tube 32 is located in the second chamber 22, and the outlet of the second purge tube 32 and the second control valve 321 are both located outside the heat preservation chamber 2.

[0046] The above embodiments are only to illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and modifications, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. Flue gas circulation sampling and measuring device, characterized in that: include: A sampling assembly (1) comprises a sampling tube, wherein the sampling tube is arranged on the cavity wall of a chamber to be tested (100), smoke flows in the chamber to be tested (100), and the sampling tube comprises an air inlet pipe (11) and an air return pipe (12); A heat preservation chamber (2) is located outside the chamber to be tested (100), the heat preservation chamber (2) comprising a first chamber (21) and a second chamber (22) which are connected via a circulation fan (4), the first chamber (21) being connected to the chamber to be tested (100) via the air inlet pipe (11), and the second chamber (22) being connected to the chamber to be tested (100) via the air return pipe (12); the circulation fan (4) is used to enable the smoke in the chamber to be tested (100) to flow through the air inlet pipe (11), the first chamber (21), and the second chamber (22) in sequence, and to flow back to the chamber to be tested (100) via the air return pipe (12); the temperature in the heat preservation chamber (2) is higher than a first preset temperature; A measuring component (6) is partially disposed in the first cavity (21), and the measuring component (6) is used to measure a specified index of the smoke flowing through the first cavity (21).

2. The flue gas circulation sampling and measuring device according to claim 1, characterized in that: The sampling assembly (1) further comprises an isolation plate (14); the isolation plate (14), the air inlet (111) of the air inlet pipe (11) and the air return port (121) of the air return pipe (12) are all located in the chamber to be tested (100); the isolation plate (14) is arranged between the air inlet (111) and the air return port (121).

3. The flue gas circulation sampling and measuring device according to claim 2, characterized in that: The sampling assembly (1) further comprises a protection tube (13), wherein the protection tube (13) is inserted into the cavity wall of the cavity (100) to be tested; the isolation plate (14) is arranged in the protection tube (13); the isolation plate (14) is used to separate the protection tube (13) into a first tube (131) and a second tube (132); a gas outlet (1321) is arranged on the side wall of the second tube (132); the return tube (12) is located in the second tube (132); the gas outlet (1321) is communicated with the return tube (121); the gas inlet tube (11) is passed through the return tube (12); and the gas inlet (111) extends into the first tube (131).

4. The flue gas circulation sampling and measuring device according to claim 3, characterized in that: The smoke flowing in the chamber to be tested (100) has a preset flow direction, and the air inlet (111) and the port (1311) of the protection tube (13) located in the chamber to be tested (100) are both inclined structures that gradually incline toward one side of the return air pipe (12) in the preset flow direction.

5. The flue gas circulation sampling and measuring device according to claim 3, characterized in that: The smoke flowing in the chamber to be tested (100) has a preset flow direction, and the gas outlet (1321) is arranged on the leeward side of the protection tube (13).

6. The flue gas circulation sampling and measuring device according to claim 1, characterized in that: The flue gas circulation sampling and measuring device further comprises a purge assembly (3), the purge assembly (3) comprising a first purge tube (31) and a second purge tube (32), the first purge tube (31) being connected to the first cavity (21), the first purge tube (31) being used to pass gas at a first temperature into the cavity (100) to be measured, the second purge tube (32) being connected to the second cavity (22), the second purge tube (32) being used to pass gas at a second temperature into the cavity (100) to be measured.

7. The flue gas circulation sampling and measuring device according to claim 6, characterized in that: The first purge pipe (31) is provided with a first control valve (311), and the inlet of the first purge pipe (31) is connected to the outlet of the first purge pipe (31) through the first control valve (311); The second purge pipe (32) is provided with a second control valve (321), and the inlet of the second purge pipe (32) is connected to the outlet of the second purge pipe (32) through the second control valve (321).

8. The flue gas circulation sampling and measuring device according to any one of claims 1 to 7, characterized in that: The flue gas circulation sampling and measuring device also includes a motor (5), and the output shaft of the motor (5) is connected to the circulation fan (4).

9. The flue gas circulation sampling and measuring device according to any one of claims 1 to 7, characterized in that: The outer wall of the heat-insulating cavity (2) is provided with a heat-insulating layer (23).

10. The flue gas circulation sampling and measuring device according to any one of claims 1 to 7, characterized in that: The measuring component (6) is an acid dew point temperature measuring mechanism, and the acid dew point temperature measuring mechanism is used to measure the acid dew point temperature of the flue gas in the first chamber (21).

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