Heat tracing pipe for flue gas sampling

Abstract

The invention relates to the technical field of flue gas sampling, in particular to a heat tracing pipe for flue gas sampling, which comprises a pipe body, a sampling pipe, a heat tracing mechanism and a calibration pipe, the sampling pipe, the heat tracing mechanism and the calibration pipe are arranged in the pipe body, the sampling pipe is close to the heat tracing mechanism and is arranged in the middle of the pipe body, and the calibration pipe is arranged in the pipe body. The calibration pipe is installed on the side, away from the heat tracing mechanism, of the pipe body, the heat tracing pipe connector mechanisms are installed on the two sections of the heat tracing pipe, the heat preservation mechanism comprises a cold point heat preservation assembly, a pipe wall heat preservation assembly and a connector heat preservation assembly, the cold point heat preservation assembly is installed in the pipe body, and the pipe wall heat preservation assembly is installed in the pipe body. The pipe wall heat preservation assembly is arranged on the pipe wall in a sleeving mode, and the connector heat preservation assembly is installed on the heat tracing pipe connector mechanism. The multiple sections of heat tracing pipes can be connected to the proper using length through the heat tracing pipe connector mechanism, the heat preservation mechanism can conduct heat preservation on the positions where cold points are prone to occurring, and the poor heat tracing effect is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas sampling, in particular to a heat tracing pipe for flue gas sampling. Background Art

[0002] In the context of exhaust gas monitoring, a heat tracer generally refers to a pipe used to heat exhaust gas. Its function is to maintain the temperature of the exhaust gas during transmission to prevent pollutants in the exhaust gas from condensing or crystallizing, thereby affecting the accuracy of the monitoring results. Heat tracers are usually used together with exhaust gas sampling tubes to transmit the heated exhaust gas to the monitoring equipment for analysis. By using heat tracers, it can be ensured that the exhaust gas maintains a stable temperature during transmission and reduce errors caused by temperature changes. Different exhaust gas monitoring applications may require different types of heat tracers. For example, some heat tracers may be heated by electricity or steam, while others may be heated by thermal oil or other media. Choosing a suitable heat tracer requires considering factors such as the characteristics of the exhaust gas, the requirements of the monitoring equipment, and the actual operating conditions.

[0003] However, the existing single length of the heating pipe is fixed and cannot be used flexibly according to the actual usage scenario. Although there are heating pipes as described in application number CN202410153761.4 that achieve the adjustment of the length of the heating pipe by connecting the sections of the heating pipe to each other, cold spots will appear during use, that is, the unheated parts in the heating pipe system, and these parts have a lower temperature during operation. The problem of cold spots in heating pipes mainly occurs in the installation of sampling probes, pipeline connections, and parameter settings. That is, cold spots are prone to appear at the connection of the heating pipes, resulting in poor heating effects and affecting the normal operation of the system.

[0004] Therefore, a heat tracing tube for flue gas sampling is proposed. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the fact that the above-mentioned existing heating pipes cannot be adjusted in length according to actual conditions and cold spots may appear at the connection points of the heating pipes, the present invention is proposed.

[0007] Therefore, the object of the present invention is to provide a heating tube for flue gas sampling, the purpose of which is to adjust the use length of the heating tube by splicing, and to heat and insulate the cold spot position to avoid poor heating effect.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] A heating pipe for flue gas sampling comprises a pipe body, a sampling pipe, a heating mechanism and a calibration pipe, wherein the sampling pipe, the heating mechanism and the calibration pipe are installed inside the pipe body, the sampling pipe is close to the heating mechanism and installed in the middle of the pipe body, the calibration pipe is installed on the side of the pipe body away from the heating mechanism, and further comprises a heating pipe joint mechanism and a heat preservation mechanism, wherein the heating pipe joint mechanism is installed at two sections of the heating pipe, the heat preservation mechanism comprises a cold spot heat preservation component, a pipe wall heat preservation component and a joint heat preservation component, the cold spot heat preservation component is installed inside the pipe body, the pipe wall heat preservation component is sleeved on the pipe wall, and the joint heat preservation component is installed at the heating pipe joint mechanism.

[0010] The heating pipe joint mechanism can connect multiple sections of heating pipes to a suitable length for use, and the insulation mechanism can insulate locations where cold spots are likely to occur, thereby avoiding poor heating effects.

[0011] As a preferred embodiment of the present invention, the heating pipe for flue gas sampling comprises a first joint and a second joint, and the first joint and the second joint can be plugged into each other so that sampling pipes on different heating pipes are connected to the heating mechanism.

[0012] The sampling tubes are internally connected, the heating mechanisms are connected in series, and are powered by a common power source. Insulating materials are required between the sampling tubes and the heating mechanisms at the first joint and the second joint.

[0013] As a preferred solution of the heat tracing tube for flue gas sampling of the present invention, the first joint includes a first fixed sleeve, a sliding sleeve, a reset torsion spring and a first pair of joints. The first fixed sleeve is sleeved on the outer wall of the end of the tube body, and its outer wall is stepped and has a bead hole. A limit bead is installed in the bead hole. The sliding sleeve is sleeved on the outer wall of the first fixed sleeve. A protrusion is arranged inside the sliding sleeve. The sliding sleeve has two points, a connection point and a separation point. When the sliding sleeve is located at the connection point, the protrusion contacts the limit bead. When the slider is located at the separation point, the protrusion separates from the limit bead. The reset torsion spring is sleeved on the outer wall of the first fixed sleeve. One end of the reset torsion spring is sleeved on the outer wall of the first fixed sleeve. It is connected to the step of the first fixed sleeve, and the other end is connected to the sliding sleeve. The first pair of joints are fixed to the outer surface of the sampling tube, the heating mechanism and the calibration tube, and are fixedly connected to the first fixed sleeve. The second joint includes a second fixed sleeve and a second pair of joints. The second fixed sleeve is sleeved on the outer wall of the end of the tube body, and the outer wall surface is provided with a first flange and a second flange. The first flange abuts against the inside of the first fixed sleeve, and the end of the first fixed sleeve abuts against the position of the second flange. The second pair of joints and the first pair of joints can be plugged into each other, and a clamping block is hingedly installed on the sliding sleeve, and a corresponding clamping groove is provided on the second fixed sleeve.

[0014] During the plugging process of the first connector and the second connector, it is only necessary to twist the sliding sleeve, and the connection process is simple and convenient. During the disassembly process, it is also only necessary to twist the sliding sleeve to achieve quick disassembly.

[0015] As a preferred embodiment of the heating tube for flue gas sampling of the present invention, the cold spot insulation assembly includes multiple insulation rings and heat transfer plates. The left and right sides of the insulation rings are made of high-temperature resistant high thermal expansion coefficient materials, and the upper and lower positions are made of cemented carbide materials. They are sleeved outside the sampling tube and the heating mechanism to make the sampling tube close to the heating mechanism. The heat transfer plates are made of metal materials with good thermal conductivity, connected to the insulation rings and covering the surfaces of the sampling tube and the heating mechanism.

[0016] The insulation ring can fix the sampling tube and the heating mechanism. The left and right sides of the insulation ring can be made of magnesium-aluminum alloy and other materials, and the upper and lower sides can be made of stainless steel. Due to the high thermal expansion coefficient on the left and right sides of the insulation ring, the expansion length is longer at higher temperatures and the contraction length is shorter at lower temperatures during use. Therefore, at the cold spot, the insulation rings can move closer to each other in the upper and lower directions toward the midpoint position, squeezing the sampling tube and the heating mechanism so that the sampling tube is close to the heating mechanism, improving the heat transfer efficiency. At the same time, due to the good heat transfer performance of the insulation ring material, the heat absorbed by the insulation ring and the heating mechanism can also be further transferred to the sampling tube position through the heat transfer sheet, realizing further utilization of the heat source while keeping warm.

[0017] As a preferred embodiment of the heating tube for flue gas sampling of the present invention, the tube body includes an outer sheath and an insulation layer, the outer sheath is made of material with a wall thickness of at least 3.5 mm, and the insulation layer is a glass fiber felt and a thermal insulation and tensile aluminum foil cloth bidirectionally wound.

[0018] The outer sheath protects the internal structure. The glass fiber felt has good thermal insulation properties and can effectively reduce heat conduction, thereby reducing energy loss. The aluminum foil has a good ability to reflect thermal radiation and can prevent heat from escaping through radiation. The two-way winding method can enhance the thermal insulation effect of the aluminum foil cloth, and its good moisture-proof performance can effectively prevent moisture from entering.

[0019] As a preferred solution of the heating pipe for flue gas sampling of the present invention, wherein: the tube wall insulation component is cylindrical, and its inner wall is provided with protrusions, and the outer wall of the tube body is correspondingly provided with limiting grooves, and the limiting grooves include low-level grooves and high-level grooves. The shapes of the low-level grooves and the high-level grooves are the same as the protrusions, and the two are connected by a short slope. When the protrusions are all located in the low-level grooves, the outer sheath insulation component can slide on the outer sheath, and when the protrusions are all located in the high-level grooves, the friction between the two is increased and they cannot slide relative to each other.

[0020] As a preferred solution of the heating tube for flue gas sampling of the present invention, the main body of the tube wall insulation component is made of rubber and plastic insulation material, the protrusion is made of the same material as the main body of the tube wall insulation component, and the outer wall of the tube wall insulation component is coated with aluminum foil.

[0021] The pipe wall insulation component can be fixed or slid to the position where insulation is required by twisting it. For sections with good overall use, the pipe wall insulation component may not be installed. For outdoor locations or locations with local cold sources, multiple pipes can be installed on the same heating pipe body for insulation. That is, the pipe wall insulation component can be flexibly used according to actual usage.

[0022] As a preferred embodiment of the heating pipe for flue gas sampling of the present invention, the heating mechanism includes a heating belt and a pre-buried pipe, the heating belt is a constant power electric heating belt, and the pre-buried pipe is a thin-walled pipe with a PT100 placed inside.

[0023] Pt100 is a platinum thermal resistor, and its resistance value will change with the change of temperature. Due to the relationship between the temperature value and resistance change of the PT100 thermal resistor, this characteristic is used to use the PT100 thermal resistor temperature sensor to monitor the internal temperature of the heating pipe in real time, reduce the damage rate of the heating pipe, and improve the installation efficiency.

[0024] As a preferred embodiment of the heating pipe for flue gas sampling of the present invention, the joint insulation component includes a silicone heating plate, a fixed wiring point and a sliding wiring point, the silicone heating plate is coated on the second fixed sleeve and is located between the first flange and the second flange, the fixed wiring point is arranged on the first fixed sleeve, and the sliding wiring point is arranged on the sliding sleeve, when the first fixed sleeve is plugged into the second fixed sleeve, the silicone heating plate is electrically connected to the fixed connection point, and when the sliding sleeve is located at the connection point, the sliding wiring point is electrically connected to the fixed wiring point.

[0025] When the first joint and the second joint are connected to each other, the silicone heating sheet, the fixed wiring point and the sliding wiring point are connected to each other and the circuit is connected. The silicone heating sheet releases heat to heat the connection position between the two. Since the heating temperature is high, a heat-insulating material can be set on the outside of the sliding sleeve to prevent the staff from accidentally touching and scalding during use. The fixed wiring point can be set with two contacts, one connected to the silicone heating sheet and the other connected to the power supply of the heating belt. The sliding wiring point can connect the above two contacts, so that the silicone heating sheet can release heat without adding an additional power supply during use.

[0026] As a preferred solution of the heat tracing tube for flue gas sampling of the present invention, the sampling tube is made of metal to prevent the volatilization of non-methane total hydrocarbons and benzene series.

[0027] Beneficial effects of the present invention:

[0028] 1. The first joint and the second joint are connected to each other, and the detachable design facilitates the extension or shortening of the heating pipe to adapt to the usage. The heating pipe transports the flue gas to the next process in a stable insulation state, and the process of connecting the heating pipes to each other only requires twisting the sliding sleeve to achieve quick disassembly and assembly, which is simple and convenient.

[0029] 2. The cold spot insulation components, pipe wall insulation components and joint insulation components are used to achieve insulation for different positions and situations of the heating pipe. In particular, the joint insulation components can automatically complete the connection when the heating pipe is connected. The heat release of the silicone heating sheet can avoid the appearance of cold spots at the joints without the need for additional power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0031] Figure 1 It is a schematic diagram of the overall structure of the heat tracing pipe for flue gas sampling of the present invention.

[0032] Figure 2 This is a cross-sectional view of the first joint and the second joint of the present invention when they are butt-jointed.

[0033] Figure 3 for Figure 2 Enlarged view of point A.

[0034] Figure 4 It is a cross-sectional view of the heating pipeline of the present invention.

[0035] Figure 5 for Figure 4 Enlarged view of point B.

[0036] In the figure: 1, pipe body; 11, outer sheath; 12, insulation layer; 2, sampling tube; 3, heating mechanism; 31, heating belt; 32, embedded pipe; 4, calibration tube; 5, heating pipe joint mechanism; 51, first joint; 511, first fixing sleeve; 512, sliding sleeve; 512a, bump; 513, reset torsion spring; 514, first pair of joints; 515, bead hole; 516, limit bead; 52, second joint; 521, second fixing sleeve; 522 , second pair of joints; 523, first flange; 524, second flange; 53, block; 54, slot; 6, insulation mechanism; 61, cold spot insulation assembly; 611, insulation ring; 612, heat transfer plate; 62, pipe wall insulation assembly; 621, protrusion; 622, limit groove; 622a, low position groove; 622b, high position groove; 63, joint insulation assembly; 631, silicone heating plate; 632, fixed connection point; 633, sliding connection point. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0040] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0041] See also Figures 1 to 5 The present invention provides a heat tracing pipe for flue gas sampling, and the technical solution is as follows:

[0042] Reference Figure 1A heating pipe for flue gas sampling includes a pipe body 1, a sampling pipe 2, a heating mechanism 3 and a calibration pipe 4. The sampling pipe 2, the heating mechanism 3 and the calibration pipe 4 are installed inside the pipe body 1. The sampling pipe 2 is close to the heating mechanism 3 and installed in the middle of the pipe body 1. The calibration pipe 4 is installed on the side of the pipe body 1 away from the heating mechanism 3. It also includes a heating pipe joint mechanism 5 and an insulation mechanism 6. The heating pipe joint mechanism 5 is installed at two sections of the heating pipe. The insulation mechanism 6 includes a cold spot insulation component 61, a pipe wall insulation component 62 and a joint insulation component 63. The cold spot insulation component 61 is installed inside the pipe body 1, the pipe wall insulation component 62 is sleeved on the pipe wall, and the joint insulation component 63 is installed at the heating pipe joint mechanism 5.

[0043] Reference Figure 1 and Figure 2 The heating pipe joint mechanism 5 includes a first joint 51 and a second joint 52. The first joint 51 and the second joint 52 can be plugged into each other so that the sampling pipes 2 on different heating pipes are connected to the heating mechanism 3.

[0044] Reference Figure 2 The first joint 51 includes a first fixed sleeve 511, a sliding sleeve 512, a reset torsion spring 513 and a first pair of joints 514. The first fixed sleeve 511 is sleeved on the outer wall of the end of the tube body 1. The outer wall is stepped and has a bead hole 515. A limit bead 516 is installed in the bead hole 515. The sliding sleeve 512 is sleeved on the outer wall of the first fixed sleeve 511. A protrusion 512a is arranged inside the sliding sleeve 512. The sliding sleeve 512 has two points, a connection point and a separation point. When the sliding sleeve 512 is located at the connection point, the protrusion 512a contacts the limit bead 516. When the slider is located at the separation point, the protrusion 512a is separated from the limit bead 516. The reset torsion spring 513 is sleeved on the outer wall of the first fixed sleeve 511, and one end of the reset torsion spring is sleeved on the outer wall of the first fixed sleeve 511. 1, and the other end is connected to the sliding sleeve 512. The first pair of joints 514 is fixed to the outer surfaces of the sampling tube 2, the heating mechanism 3 and the calibration tube 4, and is fixedly connected to the first fixing sleeve 511. The second joint 52 includes a second fixing sleeve 521 and a second pair of joints 522. The second fixing sleeve 521 is sleeved on the outer wall of the end of the tube body 1, and the outer wall surface thereof is provided with a first flange 523 and a second flange 524. The first flange 523 abuts against the first fixing sleeve 511, and the outer diameter of the first flange 523 is equal to the inner diameter of the first fixing sleeve 511. The second pair of joints 522 and the first pair of joints 514 can be plugged into each other. A clamping block 53 is hingedly installed on the sliding sleeve 512, and a corresponding clamping groove 54 is opened on the second fixing sleeve 521.

[0045] Reference Figure 4 and Figure 5The cold spot insulation component 61 includes multiple insulation rings 611 and heat transfer sheets 612. The left and right sides of the insulation rings 611 are made of high-temperature resistant high thermal expansion coefficient materials, and the upper and lower positions are made of hard alloy materials. They are sleeved outside the sampling tube 2 and the heating mechanism 3 to make the sampling tube 2 close to the heating mechanism 3. The heat transfer sheet 612 is made of a metal material with good thermal conductivity, connected to the insulation ring 611 and covering the surface of the sampling tube 2 and the heating mechanism 3.

[0046] Reference Figure 1 and Figure 4 The pipe body 1 includes an outer sheath 11 and a heat-insulating layer 12. The outer sheath 11 is made of PVC with a wall thickness of at least 3.5 mm. The heat-insulating layer 12 is a glass fiber felt and a heat-insulating tensile aluminum foil cloth bidirectionally wound.

[0047] Reference Figure 1 , Figure 4 and Figure 5 The pipe wall insulation component 62 is cylindrical, and a protrusion 621 is provided on its inner wall. A limiting groove 622 is correspondingly provided on the outer wall of the pipe body 1. The limiting groove 622 includes a low groove 622a and a high groove 622b. The low groove 622a and the high groove 622b have the same shape as the protrusion 621, and the two are connected by a short slope. When the protrusions 621 are all located in the low groove 622a, the outer sheath 11 insulation component can slide on the outer sheath 11. When the protrusions 621 are all located in the high groove 622b, the friction between the two increases and they cannot slide relative to each other.

[0048] Reference Figure 5 The main body of the pipe wall insulation component 62 is a rubber-plastic insulation material, the protrusion 621 is made of the same material as the main body of the pipe wall insulation component 62, and the outer wall of the pipe wall insulation component 62 is coated with an aluminum foil coating.

[0049] Reference Figure 4 The heating mechanism 3 includes a heating belt 31 and a pre-buried pipe 32. The heating belt 31 is a constant power electric heating belt 31. The pre-buried pipe 32 is a thin-walled pipe with a PT100 placed inside.

[0050] Reference Figure 3 The joint insulation component 63 includes a silicone heating plate 631, a fixed connection point 632 and a sliding connection point 633. The silicone heating plate 631 is covered on the second fixed sleeve 521 and is located between the first flange 523 and the second flange 524. The fixed connection point 632 is arranged on the first fixed sleeve 511, and the sliding connection point 633 is arranged on the sliding sleeve 512. When the first fixed sleeve 511 and the second fixed sleeve 521 are plugged into each other, the silicone heating plate 631 is electrically connected to the fixed connection point. When the sliding sleeve 512 is located at the connection point, the sliding connection point 633 is electrically connected to the fixed connection point 632.

[0051] Reference Figure 4 The sampling tube 2 is made of metal to prevent the volatilization of non-methane hydrocarbons and benzene series.

[0052] When in use, multiple sections of heating pipes can be connected according to actual conditions, and the pipe wall insulation component 62 can be installed at appropriate positions according to actual use temperature conditions. The use process of the pipe wall insulation component 62 is as follows: when a specific position needs to be insulated, the pipe wall insulation component 62 is twisted as a whole so that the protrusion 621 is located at the low-level groove 622a. At this time, the pipe wall insulation component 62 can be slid to an appropriate position, and then the pipe wall insulation component 62 is twisted in the opposite direction again so that the protrusion 621 slides to the high-level groove 622b, thereby increasing the mutual pressure between the pipe wall insulation component 62 and the pipe body 1, thereby increasing the friction between the two, so that the pipe wall insulation component 62 will not be displaced. The operating principle of the cold spot insulation component 61 is as follows: the insulation ring 611 can fix the sampling tube 2 and the heating mechanism 3. The left and right sides of the insulation ring 611 can be made of materials such as magnesium-aluminum alloy, and the upper and lower sides can be made of stainless steel. Since the thermal expansion coefficients of the left and right sides of the insulation ring are relatively high, the expansion length is longer at higher temperatures and the contraction length is shorter at lower temperatures during use. Therefore, at the cold spot position, the insulation rings can approach each other toward the midpoint in the upper and lower directions, squeezing the sampling tube 2 and the heating mechanism 3, so that the sampling tube 2 is close to the heating mechanism 3, thereby improving the heat transfer efficiency. At the same time, due to the good heat transfer performance of the insulation ring material, the heat absorbed by the insulation ring and the heating mechanism 3 can also be further transferred to the sampling tube 2 position through the heat transfer sheet 612, thereby achieving further utilization of the heat source while keeping warm. The connection process of the heat tracing pipe is as follows: the sliding sleeve 512 is rotated to make the slider 512 located at the separation point, at which time the protrusion 512a does not contact the limiting bead 516, the second fixing sleeve 521 is inserted into the first fixing sleeve 511, at which time the first pair of joints 514 and the second pair of joints 522 are also plugged into each other, the first flange 523 is pressed against the inside of the first fixing sleeve 511, and the end of the first fixing sleeve 511 is pressed against the position of the second flange 524, at which time the sliding sleeve 512 is released, so that the sliding sleeve 512 is reset under the action of the reset torsion spring 513, and the block 53 is deflected and engaged with the slot 54, and the connection is completed. After the connection is completed, the silicone heating plate coated on the second fixing sleeve, the fixed wiring point set on the first fixing sleeve and the sliding wiring point on the sliding sleeve are connected to each other, so that the circuit is connected to power the silicone heating plate, so that the silicone heating plate heats the connection of the heat tracing pipe to avoid the appearance of cold spots at the connection position.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat tracing tube for flue gas sampling, comprising a tube body (1), a sampling tube (2), a heat tracing mechanism (3) and a calibration tube (4), wherein the sampling tube (2), the heat tracing mechanism (3) and the calibration tube (4) are installed inside the tube body (1), the sampling tube (2) is close to the heat tracing mechanism (3) and installed in the middle of the tube body (1), and the calibration tube (4) is installed on the side of the tube body (1) away from the heat tracing mechanism (3), characterized in that: It also comprises a heating pipe joint mechanism (5) and a heat preservation mechanism (6), wherein the heating pipe joint mechanism (5) is installed at both ends of the heating pipe, and the heat preservation mechanism (6) comprises a cold spot heat preservation component (61), a pipe wall heat preservation component (62) and a joint heat preservation component (63), wherein the cold spot heat preservation component (61) is installed inside the pipe body (1), the pipe wall heat preservation component (62) is sleeved on the pipe wall, and the joint heat preservation component (63) is installed at the heating pipe joint mechanism (5).

2. The heat tracing tube for flue gas sampling according to claim 1, characterized in that: The heating pipe joint mechanism (5) comprises a first joint (51) and a second joint (52), wherein the first joint (51) and the second joint (52) can be plugged into each other so that sampling pipes (2) on different heating pipes are connected to the heating mechanism (3).

3. The heat tracing tube for flue gas sampling according to claim 2, characterized in that: The first joint (51) comprises a first fixed sleeve (511), a sliding sleeve (512), a return torsion spring (513) and a first pair of joints (514). The first fixed sleeve (511) is sleeved on the outer wall of the end of the tube body (1). The outer wall is stepped and has a bead hole (515). A limit bead (516) is installed in the bead hole (515). The sliding sleeve (512) is sleeved on the outer wall of the first fixed sleeve (511). The sliding sleeve A protrusion (512a) is arranged inside the first fixed sleeve (512), and the sliding sleeve (512) has two points, a connection point and a separation point. When the sliding sleeve (512) is located at the connection point, the protrusion (512a) contacts the limiting bead (516), and when the sliding sleeve is located at the separation point, the protrusion (512a) separates from the limiting bead (516). The reset torsion spring (513) is sleeved on the outer wall of the first fixed sleeve (511), and one end of the reset torsion spring is connected to the outer wall of the first fixed sleeve (511). The first pair of joints (514) are fixed to the outer surfaces of the sampling tube (2), the heating mechanism (3) and the calibration tube (4), and are fixedly connected to the first fixing sleeve (511). The second joint (52) comprises a second fixing sleeve (521) and a second pair of joints (522). The second fixing sleeve (521) is sleeved on the outer wall of the end of the tube body (1), and a first flange (523) and a second flange (524) are arranged on the outer wall surface. The first flange (523) abuts against the inside of the first fixing sleeve (511), and the end of the first fixing sleeve (511) abuts against the position of the second flange (524). The second pair of joints (522) and the first pair of joints (514) can be plugged into each other. A clamping block (53) is hingedly installed on the sliding sleeve (512), and a corresponding clamping groove (54) is provided on the second fixing sleeve (521).

4. The heat tracing tube for flue gas sampling according to claim 1 or 3, characterized in that: The cold spot insulation component (61) comprises a plurality of insulation rings (611) and heat transfer sheets (612). The insulation rings (611) are made of high-temperature resistant high thermal expansion coefficient materials on the left and right sides, and hard alloy materials on the upper and lower sides. They are sleeved outside the sampling tube (2) and the heating mechanism (3) so that the sampling tube (2) is in close contact with the heating mechanism (3). The heat transfer sheets (612) are made of metal materials with good thermal conductivity, connected to the insulation rings (611) and covering the surfaces of the sampling tube (2) and the heating mechanism (3).

5. The heat tracing tube for flue gas sampling according to claim 4, characterized in that: The pipe body (1) comprises an outer sheath (11) and a heat-insulating layer (12); the outer sheath (11) is made of PVC material and has a wall thickness of at least 3.5 mm; the heat-insulating layer (12) is a glass fiber felt and a heat-insulating tensile-resistant aluminum foil cloth wound in a bidirectional manner.

6. The heat tracing tube for flue gas sampling according to claim 5, characterized in that: The tube wall insulation component (62) is cylindrical, and a protrusion (621) is provided on its inner wall. A limiting groove (622) is correspondingly provided on the outer wall of the tube body (1). The limiting groove (622) comprises a low-position groove (622a) and a high-position groove (622b). The low-position groove (622a) and the high-position groove (622b) have the same shape as the protrusion (621). The two are connected by a short slope. When the protrusions (621) are all located in the low-position groove (622a), the outer sheath (11) insulation component can slide on the outer sheath (11). When the protrusions (621) are all located in the high-position groove (622b), the friction between the two is increased and they cannot slide relative to each other.

7. The heat tracing tube for flue gas sampling according to claim 6, characterized in that: The main body of the pipe wall insulation component (62) is made of rubber and plastic insulation material, the protrusion (621) is made of the same material as the main body of the pipe wall insulation component (62), and the outer wall of the pipe wall insulation component (62) is coated with an aluminum foil coating.

8. The heat tracing tube for flue gas sampling according to claim 7, characterized in that: The heating mechanism (3) comprises a heating belt (31) and a pre-buried pipe (32); the heating belt (31) is a constant power electric heating belt (31); the pre-buried pipe (32) is a thin-walled pipe with a PT100 placed inside.

9. The heat tracing tube for flue gas sampling according to claim 8, characterized in that: The joint insulation component (63) comprises a silicone heating plate (631), a fixed connection point (632) and a sliding connection point (633); the silicone heating plate (631) is coated on the second fixed sleeve (521) and is located between the first flange (523) and the second flange (524); the fixed connection point (632) is arranged on the first fixed sleeve (511); the sliding connection point (633) is arranged on the sliding sleeve (512); when the first fixed sleeve (511) and the second fixed sleeve (521) are plugged in, the silicone heating plate (631) is electrically connected to the fixed connection point; when the sliding sleeve (512) is located at the connection point, the sliding connection point (633) is electrically connected to the fixed connection point (632).

10. The heat tracing tube for flue gas sampling according to claim 9, characterized in that: The sampling tube (2) is made of metal to prevent the volatilization of non-methane total hydrocarbons and benzene series.

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