A heat pipe axial compensation device

Abstract

The application provides a heat pipe axial compensation device, which comprises an inner working pipe, an outer protective pipe and a steam seal device, the first end of the outer protective pipe is sleeved outside the outer wall of the inner working pipe, a sealing filler is arranged between the inner wall of the first end of the outer protective pipe and the outer wall of the inner working pipe, the steam seal device is arranged in the outer protective pipe and is spaced from the sealing filler, the steam seal device comprises a plurality of steam seal rings which are arranged along the length direction of the outer protective pipe, the outer wall of the steam seal ring is fixedly connected with the inner wall of the outer protective pipe, a row of tooth blocks are uniformly distributed on the inner wall of the steam seal ring, the tooth blocks on two adjacent steam seal rings are staggered, and a gap is left between the end of the tooth block away from the steam seal ring and the outer wall of the inner working pipe. The application has good sealing performance, stable and reliable sealing structure and can reduce the space requirement during arrangement of the compensation device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heat pipe compensation device, and particularly relates to a heat pipe axial compensation device. BACKGROUND

[0002] At present, the urban heat supply pipe network plays an irreplaceable bearing and conveying role in meeting the heat demand of various industrial enterprises, realizing centralized heat supply and replacing various enterprise self-provided scattered small boilers. The heat pipe will cause thermal expansion and contraction due to the influence of internal medium temperature during the heating and cooling process. In the current engineering practice, natural compensation, additional compensators (such as corrugated compensator, sleeve telescopic compensator and rotary compensator) and other measures are generally used to compensate the thermal displacement of the pipe.

[0003] Natural compensation has a large impact on the plane or space size of pipe arrangement and pipe pressure drop, and is generally only used as a local compensation measure in the heat supply pipe network. The corrugated compensator uses the alternating change of the stainless steel corrugated pipe waveform to realize thermal compensation, has good sealing performance but generates a large blind plate thrust on the pipe. In addition, the stainless steel corrugated pipe is prone to stress corrosion, and the service life of the equipment is not long. The traditional sleeve telescopic compensator is limited by the structure and working principle of the equipment. After the internal movable core pipe and the filler are rubbed and worn during movement, the sealing performance cannot be maintained in good condition for a long time. After long-term use, leakage may occur, which requires regular maintenance or replacement of the filler, affecting the continuity of production operation. In the operation of the rotary compensator, the stability of the relative rotation of the inner and outer pipes is not good due to the action of the pipe thrust, and different shaft eccentric deflection may occur, increasing the rotation resistance and reducing the flexibility of rotary compensation. In addition, the working principle of the rotary compensator requires that it must be arranged on a pair of vertical pipes, which requires a high space reservation in the horizontal and vertical directions at the position where the rotary compensator is arranged. On the one hand, it is difficult to meet the requirements due to the constraints of the actual engineering site, and on the other hand, it also affects the overall appearance of the outdoor.

[0004] Therefore, in view of the current engineering actual situation, in order to ensure the long-term stable and economic operation of the heat supply pipe network, it is necessary to design a heat pipe axial compensation device with good sealing performance, stable and reliable sealing structure and reduced space requirement for the arrangement of the compensation device. SUMMARY

[0005] The purpose of the present application is to provide a heat pipe axial compensation device with good sealing performance, stable and reliable sealing structure and reduced space requirement for the arrangement of the compensation device.

[0006] The present application is realized by the following technical solutions:

[0007] A thermal pipeline axial compensation device includes an inner working tube, an outer protective tube and a steam seal device. The first end of the outer protective tube is sleeved on the outside of the inner working tube. A sealing filler is provided between the inner wall of the first end of the outer protective tube and the outer wall of the inner working tube. The gas seal device is located in the outer protective tube and is spaced apart from the sealing filler. The steam seal device includes a plurality of steam seal rings spaced apart along the length direction of the outer protective tube. The outer wall of the steam seal ring is fixedly connected to the inner wall of the outer protective tube. A circle of tooth blocks is uniformly distributed on the inner wall of the steam seal ring. The tooth blocks on two adjacent steam seal rings are staggered. A gap is left between the end of the tooth block away from the steam seal ring and the outer wall of the inner working tube.

[0008] Furthermore, the steam sealing device also includes a plurality of steam guide pipes corresponding one to one with the plurality of steam sealing rings. A first through hole and a second through hole are respectively opened on the outer wall of the outer protective pipe at the left and right sides of each steam sealing ring. The two ends of the steam guide pipe are respectively connected to the first through hole and the second through hole located on both sides of the corresponding steam sealing ring.

[0009] Furthermore, a throttling orifice plate is provided on the steam guide pipe.

[0010] Furthermore, it also includes a drain pipe, a third through hole is opened on the outer protective pipe between the steam seal device and the sealing packing, one end of the drain pipe is connected to the third through hole, and a drain valve group is provided on the drain pipe

[0011] Furthermore, it also includes a rolling device for guiding, one end of the rolling device is connected to the outer wall of one end of the inner working tube located in the outer protective tube, and the other end is slidably connected to the inner wall of the outer protective tube.

[0012] Furthermore, the rolling device includes several rolling assemblies arranged at intervals along the circumference of the inner working tube. The rolling assembly includes a support frame, a rotating shaft and a roller. The rotating shaft is arranged in the support frame, and the roller rotates on the rotating shaft. The outer wall of the roller contacts the inner wall of the outer protective tube.

[0013] Furthermore, positioning pins are respectively provided on the rotating shaft at positions on both sides of the roller.

[0014] Furthermore, the inner working pipe and the outer protective pipe are both made from finished steel pipes, and the thermal expansion coefficient of the sealing filler is greater than that of the steel.

[0015] Furthermore, a packing gland is provided on the first end of the outer protective tube.

[0016] Furthermore, the tooth block is triangular in shape, and one side of the triangle of the tooth block is fixedly connected to the inner wall of the outer protective tube.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) By setting up a two-stage sealing structure consisting of a steam seal device and a sealing packing, the sealing performance is good, the sealing structure is stable, and zero leakage can be achieved; the tooth blocks on the two adjacent steam seal rings in the device of the present invention are staggered. When axial leakage steam flows through the steam seal device, the leakage steam flow and pressure are greatly reduced by the multiple blocking effects of the steam seal rings at each stage, so that the leakage steam flow and pressure at the end of the steam seal device are both small, creating a better working environment for the subsequent stage sealing packing to play an annular blocking role, which not only greatly reduces the setting length of the sealing packing and reduces the manufacturing cost, but also helps to significantly extend the service life of the sealing packing;

[0019] (2) The steam seal device is a purely mechanical component with a stable and reliable structure and a stable sealing effect. This enables the present invention to achieve excellent sealing performance while having stable, reliable and durable functions, which is conducive to reducing operation and maintenance costs;

[0020] (3) The interval length between the steam seal ring at the end of the steam seal device and the sealing packing is the compensation capacity length of the present invention. This interval length can be set according to actual engineering needs without affecting the working performance of the two-stage combined sealing structure, with large expansion acceptance and large compensation capacity;

[0021] (4) The arrangement of the present invention is as a part of the pipeline, and is directly arranged on the horizontal pipeline. There are no requirements for the horizontal and vertical spatial dimensions of the arrangement position of the present invention, and the arrangement adaptability is wide. At the same time, the present invention has no throttling elements that hinder the flow of fluid inside, and when arranged on the thermal network, there is no need to add additional pipe fittings to the pipeline to change the spatial direction, and the pressure drop resistance to the thermal network is small. In addition, the inner working pipe and the outer protective pipe of the present invention are made of typical finished pipes in service, and can be fully matched with thermal networks of various pipe diameters in actual engineering, and the pipe diameter adaptability is wide.

[0022] (5) The present invention has incomparable technical and economic advantages, and will bring about major technological changes in the design, layout and operation of steam pipe networks, hot water pipe networks, etc. It has broad application prospects in the field of axial compensation technology for thermal pipe networks and is of vital practical significance for maintaining the continuous, reliable and stable operation of thermal pipe networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of the axial compensation device for thermal pipelines of the present invention;

[0024] Figure 2 This is a schematic structural diagram of a steam seal assembly in an axial compensation device for a thermal pipeline according to the present invention;

[0025] Figure 3 Schematic diagram of the connection between the steam seal ring, the inner working pipe and the outer protective pipe in the axial compensation device for thermal pipelines of the present invention;

[0026] Figure 4 for Figure 1 AA view;

[0027] Figure 5 This is a front view of the rolling assembly in the axial compensation device for thermal pipelines of the present invention;

[0028] Figure 6 It is a side view of the rolling assembly in the axial compensation device of the thermal pipeline of the present invention.

[0029] In the figure, 1-inner working tube, 2-outer protective tube, 3-steam seal device, 31-steam seal ring, 32-tooth block, 33-steam guide pipe, 34-throttle orifice plate, 4-sealing packing, 5-drain pipe, 51-drain valve group, 6-rolling assembly, 61-support frame, 62-rotating shaft, 63-roller, 7-packing gland. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0032] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are used only to distinguish the description and should not be understood as indicating or implying relative importance.

[0033] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0034] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0035] See also Figure 1 、 Figure 2 and Figure 3 , Figure 1 This is a schematic diagram of the structure of the axial compensation device for thermal pipelines of the present invention. Figure 2 This is a schematic structural diagram of the steam seal assembly in the thermal pipeline axial compensation device of the present invention. Figure 3 Schematic diagram of the connection between the steam seal rings, the inner working tube, and the outer protective tube in the axial compensation device for thermal pipelines of the present invention. A thermal pipeline axial compensation device includes an inner working tube 1, an outer protective tube 2, and a steam seal device 3. The first end of the outer protective tube 2 is sleeved onto the outside of the inner working tube 1. A sealing packing 4 is provided between the inner wall of the first end of the outer protective tube 2 and the outer wall of the inner working tube 1. The steam seal device 3 is located within the outer protective tube 2 and spaced apart from the sealing packing 4. The steam seal device 3 includes a plurality of steam seal rings 31 spaced along the length of the outer protective tube 2. The outer walls of the steam seal rings 31 are fixedly connected to the inner wall of the outer protective tube 2. A circle of tooth blocks 32 are uniformly distributed on the inner walls of the steam seal rings 31. The tooth blocks 32 on adjacent steam seal rings 31 are staggered, leaving a gap between the ends of the tooth blocks 32 away from the steam seal rings 31 and the outer wall of the inner working tube 1.

[0036] A two-stage sealing structure consisting of a steam seal device 3 and a sealing packing 4 is provided between the outer casing 2 and the inner working tube 1. The steam seal device 3 and the sealing packing 4 are spaced a certain distance apart. The first-stage sealing structure comprises the steam seal device 3. The tooth blocks 32 on two adjacent steam seal rings 31 in the steam seal device 3 are staggered. The combination of the multiple steam seal rings 31 forms a labyrinthine sealing structure. When axial steam leakage flows through the first-stage sealing structure, the flow rate and pressure of the axial leakage are greatly reduced by the multiple barriers provided by the steam seal rings 31, resulting in a relatively low axial steam leakage volume and pressure at the end of the steam seal device 3. The second-stage sealing structure comprises the sealing packing 4. The sealing packing 4 contacts the outer casing 2 and the inner working tube 1, respectively. Upon thermal expansion, the sealing packing 4 tightens the area between the outer casing 2 and the inner working tube 1, forming an annular packing seal that completely blocks axial steam leakage and achieves zero leakage. In one embodiment, the tooth blocks 32 are triangular, with one side of the triangle fixedly connected to the inner wall of the outer casing 2. In one embodiment, the second end of the outer protective tube 2 is in a frustum shape.

[0037] To reduce the blind plate thrust of axial steam leakage on the steam seal ring 31, in one embodiment, the steam seal device 3 further includes a steam guide pipe 33 corresponding to each steam seal ring 31. A first through hole and a second through hole are respectively formed on the outer wall of the outer protective tube 2, located on either side of the steam seal ring 31. The two ends of the steam guide pipe 33 communicate with the first through hole and the second through hole located on either side of the corresponding steam seal ring 31. To accommodate the pressure drop of axial steam leakage at the rear end of the steam seal ring 31 after throttling by the gear block 32 on the steam seal ring 31, in one embodiment, a throttling orifice 34 is provided on the steam guide pipe 33. The throttling orifice 34 is used to throttle and reduce the pressure of the steam flow at the front end of the steam seal ring 31 and guide it to the rear end of the steam seal ring 31 to match the steam pressure at the rear end of the steam seal ring 31. The arrangement of the steam duct 33 and the throttle orifice 34 ensures that the medium pressures on both sides of the steam seal ring 31 are matched, significantly reducing the blind thrust of the steam seal ring 31 caused by axial steam leakage. This significantly reduces the wall thickness requirement of the steam seal ring 31, resulting in a lighter overall structure and lower manufacturing costs. This also reduces the blind thrust of the thermal pipeline axial compensation device of the present invention on the thermal pipeline. The diameter of the steam duct 33 and the aperture of the throttle orifice 34 are determined using computational fluid dynamics (CFD) based on the operating parameters of the medium within the pipeline and the diameter of the device of the present invention. In one embodiment, the distance between the end of the tooth block 32 distal to the outer protective tube 2 and the outer wall of the inner working tube 1 is 1 to 5 mm.

[0038] To remove steam leakage between the steam seal assembly 3 and the sealing packing 4, in one embodiment, the thermal pipeline axial compensation device of the present invention further includes a drain pipe 5. A third through-hole is defined on the outer casing 2 between the steam seal assembly 3 and the sealing packing 4. One end of the drain pipe 5 is connected to the third through-hole, and a drain valve assembly 51 is provided on the drain pipe 5. The third through-hole is located at the lowest point of the outer casing 2's circumference. In actual projects, a distance is left between the drain valve assembly 51 and the location of the third through-hole on the outer casing 2. In this case, the drain pipe 5 is arranged over a long length. Due to the temperature difference between the inside and outside of the drain pipe, axial steam leakage within the drain pipe 5 condenses into water and is then discharged through the drain valve assembly 51. This eliminates axial steam leakage between the steam seal assembly 3 and the sealing packing 4, eliminates back pressure on the steam seal assembly 3, and ensures the sealing performance of the steam seal assembly. Furthermore, the drain valve assembly 51 includes two first on-off valves and a drain valve, which is positioned between the two on-off valves. Furthermore, drain pipe 5 is provided with a drain branch pipe, each end of which is connected to drain pipe 5. A second on-off valve is provided on drain pipe 5, and drain valve assembly 51 is provided on drain pipe 5 between the two ends of the drain branch pipe. This arrangement allows drain pipe 5 or the drain branch pipe to be opened as needed. For example, the drain branch pipe can be opened at the initial startup of the heating network pipeline, while the drain pipe 5 can be opened during normal operation.

[0039] Please refer to Figure 4 、 Figure 5 and Figure 6 , Figure 4 for Figure 1 AA view, Figure 5 This is the front view of the rolling assembly in the axial compensation device for thermal pipelines of the present invention. Figure 6Figure 2 is a side view of the rolling assembly in the axial compensation device for the heat pipe according to the present application. In order to limit and support the moving direction of the inner working pipe 1, in an embodiment, one end of the rolling device 6 is connected with the outer wall of the end of the inner working pipe 1 located in the outer protective pipe 2, and the other end is slidingly connected with the inner wall of the outer protective pipe 2. This arrangement makes the friction between the inner working pipe 1 and the outer protective pipe 2 during the movement of the inner working pipe 1 rolling friction, and the axial movement of the inner working pipe 1 does not drive the outer protective pipe 2 to move, thereby realizing the mutual independence of the inner working pipe 1 and the outer protective pipe 2, and ensuring that the tooth block 32 does not collide with the inner working pipe 1. In an embodiment, the rolling device 6 includes a plurality of rolling assemblies arranged at intervals along the circumference of the inner working pipe 1, and the rolling assembly includes a support frame 61, a rotating shaft 62 and a roller 63, the support frame 61 is fixedly connected with the outer wall of the inner working pipe 1, the rotating shaft 62 is arranged in the support frame 61, and the roller 63 is rotatably arranged on the rotating shaft 62, and the outer wall of the roller 63 is in contact with the inner wall of the outer protective pipe 2. When the inner working pipe 1 expands axially under the temperature action of the medium in the pipe, the inner working pipe 1 drives the plurality of rolling assemblies to move during the expansion process. Since the roller 63 is rotatably arranged on the rotating shaft 62, when the inner working pipe 1 moves axially, the roller 63 in close contact with the inner wall of the outer protective pipe 2 rotates around the rotating shaft 62, and the plurality of circumferentially arranged rollers 63 rotate, thereby supporting and guiding the inner working pipe 1 in the axial direction, thereby limiting the movement of the inner working pipe 1 only in the axial direction, and ensuring that the inner working pipe 1 does not contact the tooth block 32 of the steam seal ring 31, thereby creating conditions for the normal use of the steam seal device 3. Preferably, the center of the roller 63 is provided with a fourth through hole, and the diameter of the fourth through hole is 5-10 mm larger than the outer diameter of the rotating shaft 62. Since the contact area of the roller 63 with the inner wall of the outer protective pipe 2 is much larger than the contact area of the roller 63 with the rotating shaft 62, the friction between the inner working pipe 1 and the outer protective pipe 2 during the movement of the inner working pipe 1 is rolling friction, and the axial movement of the inner working pipe 1 does not drive the outer protective pipe 2 to move, thereby realizing the mutual independence of the inner working pipe 1 and the outer protective pipe 2.

[0040] In order to avoid excessive lateral displacement of the roller 63 on the rotating shaft 62, in an embodiment, the positions on both sides of the rotating shaft 62 are provided with positioning pins. The lateral movement of the roller 63 on the rotating shaft 62 is blocked by the positioning pins. Further, the number of rolling assemblies is determined according to the pipe diameter of the actual engineering pipeline. For example, for pipelines with a diameter of DN250 or less, four rolling assemblies can be provided, for pipelines with a diameter of DN250 to ND700, six rolling assemblies can be provided, and for pipelines with a diameter of DN700 or more, eight rolling assemblies can be provided. Preferably, the plurality of rolling assemblies are arranged at equal intervals.

[0041] In order to ensure that the sealing packing 4 can realize the annular plugging sealing between the inner working pipe 1 and the outer protective pipe 2, in an embodiment, the first end of the outer protective pipe 2 is provided with a packing gland 7. The sealing packing 4 is blocked by the packing gland 7 to avoid external leakage. In an embodiment, the inner working pipe 1 and the outer protective pipe 2 are both made of finished steel pipes, and the thermal expansion coefficient of the sealing packing 4 is larger than that of the steel material. The inner working pipe 1 and the outer protective pipe 2 are both made of steel material, and the material of the sealing packing 4 is selected to be a material such as graphite whose thermal expansion coefficient is slightly larger than that of the steel material. Under the hot operating condition, the expansion amount of the sealing packing 4 exceeds that of the steel material, so that the sealing packing 4 is expanded tightly in the packing sealing cavity, forming a tight annular seal, serving as a second sealing measure.

[0042] The following briefly describes the use process of the axial compensation device of the heat pipe:

[0043] When the inner working pipe 1 is axially expanded under the temperature action of the medium in the pipe, the inner working pipe 1 drives the rolling assembly to move in the expansion process. Since the roller 63 is rotationally connected with the rotating shaft 62, in the moving process of the inner working pipe 1 driving the rolling assembly, the roller 63 will rotate around the rotating shaft 62 and rollingly contact with the inner wall of the outer protective pipe 2, thereby playing a guiding role in the axial direction of the inner working pipe 1, limiting the inner working pipe 1 to move only in the axial direction, and ensuring that the inner working pipe 1 will not contact with the tooth block 32 on the steam seal ring 31. At the same time, since the contact area of the roller 63 with the inner wall of the outer protective pipe 2 is much larger than the contact area of the roller 63 with the rotating shaft 62, the friction between the inner working pipe 1 and the outer protective pipe 2 in the moving process is only the rolling friction between the roller 63 and the inner wall of the outer protective pipe 2, and the axial movement of the inner working pipe 1 will not drive the outer protective pipe 2 to move, thereby realizing the mutual non-influence between the inner working pipe 1 and the outer protective pipe 2.

[0044] When the axial leakage steam between the inner working tube 1 and the outer protective tube 2 flows through the first-stage steam seal ring 31 of the steam seal device 3, since a circle of triangular-shaped tooth blocks 32 are evenly distributed on the inner ring line of the steam seal ring 31, a gap of 1 to 5 mm is left between the tooth tips of the tooth blocks 32 and the outer surface of the inner working tube 1. When the axial leakage steam flows through the gap between the tooth tips of the tooth blocks 32 and the inner working tube 1, the pressure is reduced through the throttling and pressure reduction process; when the leakage steam flows through the second-stage steam seal ring 31, since the tooth blocks 32 on the second-stage steam seal ring 31 are staggered with the tooth blocks 32 on the first-stage steam seal ring 31, the axial leakage steam flows through the gap between the tooth tips of the tooth blocks 32 on the second-stage steam seal ring 31 and the inner working tube 1 and undergoes the throttling and pressure reduction process again. The pressure decreases again. Accordingly, when the axial leakage steam flows through the steam seal rings 31 step by step, it experiences a step-by-step throttling and pressure reduction process. The number of steam seal rings 31 can be set according to actual needs, so that the pressure of the axial leakage steam at the end steam seal ring 31 has been reduced to below 0.1 MPa. The setting of the steam seal device 3 enables the axial leakage steam between the inner working pipe 1 and the outer protective pipe 2 of the axial compensation device of the thermal pipeline of the present invention to have a step-by-step pressure reduction during the flow process to achieve an axial self-sealing function, and at the same time creates an excellent low-pressure working environment for the subsequent stage sealing packing 4; not only the setting length of the sealing packing 4 is greatly reduced, thereby reducing the manufacturing cost, but also it is beneficial to significantly extend the service life of the sealing packing 4.

[0045] When axial leakage steam flows through the steam seal ring 31, it will generate a blind plate thrust on the steam seal ring 31. Therefore, a steam guide pipe 33 is provided at the position of each steam seal ring 31 on the outer protective tube 2. The steam guide pipe 33 guides the steam flow at the front end of the steam seal ring 31 to the rear end of the steam seal ring 31 after throttling and reducing the pressure by the throttling orifice plate 34, so as to reduce the blind plate thrust of the steam seal ring 31 caused by the axial leakage steam. The wall thickness requirement of the steam seal ring 31 can be greatly reduced, the overall structure is relatively light, and the blind plate thrust of the axial compensation device of the thermal pipeline of the present invention on the thermal pipeline is also reduced.

[0046] The steam seal 3 acts as a barrier, significantly reducing axial steam leakage between the inner working tube 1 and the outer protective tube 2. At this point, the sealing filler 4, placed between the inner wall of the outer protective tube 2 and the outer wall of the inner working tube 1, expands due to the temperature of the medium within the inner working tube 1 and expands circumferentially between the inner wall of the outer protective tube 2 and the outer wall of the inner working tube 1, completely blocking axial steam leakage and achieving zero leakage.

[0047] A drain pipe 5 is provided at the lowest point of the circumference of the outer protective tube 2, located between the steam seal device 3 and the sealing packing 4 cavity. A distance is left between the arrangement position of the drain valve group 51 on the drain pipe 5 and the position of the through hole of the outer protective tube 2. At this time, the drain pipe 5 is arranged for a long length. Under the influence of the temperature difference between the inside and the outside, the axial leakage steam in the drain pipe 5 will be condensed into water and then discharged through the drain valve group 51. This process discharges the axial leakage steam that flows to the rear end of the final steam seal ring 31 in the axial compensation device of the thermal pipeline of the present invention, eliminates the back pressure of the steam seal assembly, and ensures the sealing performance of the steam seal assembly.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) By setting up a two-stage sealing structure consisting of a steam seal device 3 and a sealing packing 4, the sealing performance is good, the sealing structure is stable, and zero leakage can be achieved; the tooth blocks 32 on the two adjacent steam seal rings 31 in the device of the present invention are staggered. When axial leakage steam flows through the steam seal device 3, the leakage steam flow and pressure are greatly reduced by the multiple blocking effects of the steam seal rings 31 at each stage, so that the leakage steam flow and pressure at the end of the steam seal device 3 are both small, creating a better working environment for the subsequent stage sealing packing 4 to play an annular blocking role, which not only greatly reduces the setting length of the sealing packing 4 and reduces the manufacturing cost, but also helps to significantly extend the service life of the sealing packing 4;

[0050] (2) The steam seal device 3 is a purely mechanical component with a stable and reliable structure and a stable sealing effect, so that the present invention can achieve excellent sealing performance while having stable, reliable and durable functions, which is conducive to reducing operation and maintenance costs;

[0051] (3) The spacing length between the steam seal ring 31 at the end of the steam seal device 3 and the sealing packing 4 is the compensation capacity length of the present invention. This spacing length can be set according to actual engineering needs without affecting the working performance of the two-stage combined sealing structure, with large expansion acceptance and large compensation capacity;

[0052] (4) The arrangement of the present invention is as a part of the pipeline, and is directly arranged on the horizontal pipeline. There are no requirements for the horizontal and vertical spatial dimensions of the arrangement position of the present invention, and the arrangement adaptability is wide. At the same time, the present invention has no throttling elements that hinder the flow of fluid inside, and when arranged on the thermal network, there is no need to add additional pipes to change the spatial direction of the pipeline, and the pressure drop resistance to the thermal network is small. In addition, the materials of the inner working pipe 1 and the outer protective pipe 2 of the present invention are both typical finished pipes in service. They can be fully matched with thermal networks of various pipe diameters in actual engineering, and the pipe diameter adaptability is wide.

[0053] (5) The present invention has incomparable technical and economic advantages, and will bring about major technological changes in the design, layout and operation of steam pipe networks, hot water pipe networks, etc. It has broad application prospects in the field of axial compensation technology for thermal pipe networks and is of vital practical significance for maintaining the continuous, reliable and stable operation of thermal pipe networks.

[0054] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Therefore, any simple modifications, equivalent changes, and modifications to the above embodiments made in accordance with the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A thermal pipeline axial compensation device, characterized in that: The invention comprises an inner working tube, an outer protective tube and a steam sealing device, wherein the first end of the outer protective tube is sleeved on the outer side of the inner working tube, a sealing filler is provided between the inner wall of the first end of the outer protective tube and the outer wall of the inner working tube, the steam sealing device is located in the outer protective tube and is spaced apart from the sealing filler, the steam sealing device comprises a plurality of steam sealing rings spaced apart along the length direction of the outer protective tube, the outer wall of the steam sealing ring is fixedly connected to the inner wall of the outer protective tube, a circle of tooth blocks is uniformly distributed on the inner wall of the steam sealing ring, the tooth blocks on two adjacent steam sealing rings are staggered, and a gap is left between the end of the tooth block away from the steam sealing ring and the outer wall of the inner working tube; The steam seal device further includes a plurality of steam guide pipes corresponding to the plurality of steam seal rings. A first through hole and a second through hole are respectively formed on the outer wall of the outer protective pipe at positions on both sides of each steam seal ring. Both ends of the steam guide pipes are respectively connected to the first through hole and the second through hole on both sides of the corresponding steam seal ring. It also includes a drain pipe. A third through hole is opened on the outer protective pipe between the steam seal device and the sealing filler. One end of the drain pipe is connected to the third through hole. A drain valve group is provided on the drain pipe.

2. The thermal pipeline axial compensation device according to claim 1, characterized in that: A throttling orifice plate is provided on the steam guide pipe.

3. The thermal pipeline axial compensation device according to claim 1, characterized in that: It also includes a rolling device for guiding, one end of which is connected to the outer wall of one end of the inner working tube located inside the outer protective tube, and the other end is slidably connected to the inner wall of the outer protective tube.

4. The thermal pipeline axial compensation device according to claim 3, characterized in that: The rolling device includes a plurality of rolling assemblies arranged at intervals along the circumference of the inner working tube. The rolling assembly includes a support frame, a rotating shaft and a roller. The rotating shaft is arranged in the support frame. The roller is rotatably arranged on the rotating shaft. The outer wall of the roller contacts the inner wall of the outer protective tube.

5. The thermal pipeline axial compensation device according to claim 4, characterized in that: Positioning pins are respectively provided on the rotating shaft at both sides of the roller.

6. The thermal pipeline axial compensation device according to claim 1, characterized in that: The inner working pipe and the outer protective pipe are both made from finished steel pipes, and the thermal expansion coefficient of the sealing filler is greater than that of the steel.

7. The thermal pipeline axial compensation device according to claim 1, characterized in that: A packing gland is provided on the first end of the outer protective tube.

8. The thermal pipeline axial compensation device according to claim 1, characterized in that: The tooth block is triangular in shape, and one side of the triangle is fixedly connected to the inner wall of the steam seal ring.

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