Membrane type roller dryer and steam distributing device thereof

Abstract

The invention relates to a membrane type roller dryer and a steam distributing device thereof, and relates to the technical field of roller dryers, the membrane type roller dryer steam distributing device comprises an expansion unit, and the expansion unit is provided with a disc pipe formed by welding a plurality of flying disc structures in sequence; the flying saucer structure is formed by welding two symmetrical stamping saucers, the two stamping saucers are provided with conical pipe sections with the diameters gradually reduced from the middle of the flying saucer structure to the ends of the flying saucer structure, and the diameter of the large-diameter end of each conical pipe section is larger than the diameter of the small-diameter end of the corresponding conical pipe section by two times. And the wall thickness of the disc tube is greater than 1mm. Compared with a conventional metal corrugated pipe, the flying saucer structure has the advantages that the wave depth is larger, the wall thickness is larger, the self-deformation steam pressure regulating and controlling capacity is considered, meanwhile, the self-structural strength is guaranteed, and the self-service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of rotary drum dryer technology, and more particularly to a membrane rotary drum dryer and its steam distribution device. Background Technology

[0002] A membrane drum dryer is an indirect heating drying device. Its main body is a rotating, inclined membrane wall. The rotation of the drum repeatedly brings the material into continuous contact with the heat exchange tubes inside the dryer. This equipment uses steam inside seamless steel pipes for indirect heat transfer. The material is in continuous contact with the high-temperature heat exchange tubes inside the drum, and is rapidly dehydrated under steam heating.

[0003] A membrane drum dryer has a steam main and multiple heat exchange tubes installed inside the drum. Each heat exchange tube is connected to the steam main via a steam distributor. During operation, as steam is input and the material absorbs heat, the temperature inside the heat exchange tubes changes, inevitably causing the tubes to expand and contract. The steam distributor acts as a flexible buffer, absorbing excess steam pressure while ensuring that steam is input into the heat exchange tubes at a controlled pressure.

[0004] The main component of the steam distribution unit is currently the flexible metal hose. This hose primarily consists of a corrugated metal tube, a metal braided sleeve, and connectors. The metal braided sleeve is located outside the corrugated metal tube, and a connector is welded to each end of the corrugated metal tube. The corrugated metal tube is the core of the flexible metal hose, possessing excellent flexibility and corrosion resistance, while the metal braided sleeve protects it. Both the corrugated metal tube and the metal braided sleeve are flexible structures. When the steam pressure inside the corrugated metal tube is high, they can extend to release excess steam pressure; when the steam pressure decreases, they can return to their original length, thus maintaining a certain steam pressure inside the corrugated metal tube.

[0005] For the reasons mentioned above, metal bellows often need to have good deformation capacity, so their wall thickness is relatively thin, generally 0.1-0.4mm. After frequent expansion and contraction due to steam pressure, metal bellows are prone to fatigue damage. Summary of the Invention

[0006] To address the shortcomings of related technologies, this invention provides a membrane drum dryer and its steam distribution device. The dryer uses multiple saucer-shaped structures welded together to form a disc tube that undergoes elastic deformation to absorb excess steam pressure. Compared to conventional metal corrugated pipes, the saucer structure has a greater corrugation depth and wall thickness, ensuring both its ability to regulate steam pressure through deformation and its structural strength, thus extending its service life. This solves the technical problem of current metal corrugated pipes having insufficient wall thickness and being prone to fatigue damage due to frequent expansion and contraction under steam pressure.

[0007] This invention provides a steam distribution device for a membrane drum dryer, including an expansion unit. The expansion unit has a disc tube formed by welding multiple flying saucer structures in sequence. The flying saucer structure is formed by welding two symmetrical stamped discs. The two stamped discs have tapered tube sections whose diameter gradually decreases from the middle of the flying saucer structure to the end of the flying saucer structure. The diameter of the large diameter end of the tapered tube section is more than twice the diameter of the small diameter end of the tapered tube section. The wall thickness of the disc tube is greater than 1 mm.

[0008] In some embodiments, the stamping disc consists of a straight pipe section, a tapered pipe section, and a welded section that are smoothly connected along its own axis; the diameter of the welded section is equal to the major diameter of the tapered pipe section, and a bevel is provided on the side of the welded section away from the tapered pipe section.

[0009] In some embodiments, when the nominal diameter DN of the straight pipe section is less than 30, the wall thickness of the disc tube is 1.2 mm to 1.5 mm; when the nominal diameter DN of the straight pipe section is greater than 30 and less than or equal to 50, the wall thickness of the disc tube is 1.5 mm to 2.0 mm.

[0010] In some embodiments, the axis of the disc tube is a straight line; the expansion unit also has a connecting steel pipe, and the expansion unit has a plurality of disc tubes arranged in sequence, with a connecting steel pipe welded between two adjacent disc tubes.

[0011] In some embodiments, an inlet steel pipe and an outlet steel pipe are welded to both ends of the expansion unit, and the steam distribution device of the membrane drum dryer also includes a first steel pipe welded to the heat exchange tube of the membrane drum dryer, a second steel pipe welded to the steam main pipe of the membrane drum dryer, a first joint for detachably sealing the outlet steel pipe and the first steel pipe, and a second joint for detachably sealing the inlet steel pipe and the second steel pipe.

[0012] In some embodiments, the steam distribution device of the membrane drum dryer further includes a blocking plate, the outer side of which matches the shape of the inner wall of the heat exchange tube and is welded to the inner wall of the heat exchange tube, and a first steel pipe passes through the blocking plate, the outer wall of which is welded to the inner side of the blocking plate.

[0013] In some embodiments, the first connector and the second connector have the same structure. The first connector includes a first tube, a second tube, a connecting sleeve, and a sealing ring. A first limiting portion is formed on the inner side of the connecting sleeve, and a second limiting portion is formed on the inner side of the first limiting portion. A third limiting portion is formed on the outer wall of the second tube, located inside the connecting sleeve. The second tube passes through the first and second limiting portions, and the third limiting portion abuts against the second limiting portion. The first tube is threaded to the inner wall of the connecting sleeve and abuts against and communicates with the second tube. A fourth limiting portion is formed on the outer wall of the first tube, located inside the connecting sleeve. The sealing ring is sleeved on the first tube and clamped between the fourth limiting portion and the first limiting portion.

[0014] In some embodiments, the outer walls of the first and second connectors located outside the connecting sleeve are provided with planes parallel to themselves to cooperate with a wrench or socket; the outer wall of the first connector is also formed with a fifth limiting part that abuts against the connecting sleeve.

[0015] The present invention also provides a membrane drum dryer, comprising a drum body, a steam main, heat exchange tubes, and a steam distribution device for the membrane drum dryer as described in any of the above embodiments or combinations thereof; the steam main is installed in the drum body; multiple heat exchange tubes are arranged in the drum body, all heat exchange tubes are parallel to the axis of the drum body, and each heat exchange tube is connected to the steam main through one of the steam distribution devices for the membrane drum dryer; all the steam distribution devices for the membrane drum dryer do not contact each other.

[0016] In some embodiments, the heat exchange tubes are divided into multiple groups, with multiple heat exchange tubes in each group. The heat exchange tubes in different groups are positioned differently in the radial direction of the film drum dryer, and all heat exchange tubes in the same group are evenly distributed around the axis of the film drum dryer. The steam distribution devices of the film drum dryer connected to the heat exchange tubes in different groups are positioned differently in the axial direction of the film drum dryer, and the axial distance between two adjacent groups of steam distribution devices is greater than 50 mm and less than 100 mm. The steam distribution devices of the film drum dryer connected to different heat exchange tubes in the same group are positioned differently in the circumferential direction of the film drum dryer, and the circumferential distance between two adjacent groups of steam distribution devices is greater than 100 mm and less than 300 mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Compared to conventional metal bellows, the UFO structure in this invention has a greater corrugation depth and wall thickness, ensuring both its ability to regulate steam pressure through deformation and its structural strength, thus extending its service life. The increased wall thickness enhances the pressure-bearing capacity and structural stability of the UFO structure, reducing the likelihood of steam leakage in the steam distribution device of the membrane drum dryer. The increased corrugation depth compensates for the reduced flexibility due to the increased wall thickness, ensuring the UFO structure's ability to regulate internal steam pressure.

[0018] 2. In this invention, the disc tube only expands and contracts in a straight line along the axis, and the steam pressure is evenly distributed along the circumference of the disc tube, which avoids local stress concentration that may be caused by bending of the disc tube axis and helps to extend the service life of the disc tube.

[0019] 3. In this invention, the air inlet steel pipe, the expansion unit, and the air outlet steel pipe can be detachably connected to the main body of the membrane drum dryer through the first joint and the second joint, so as to facilitate the disassembly and replacement of the expansion unit on the membrane drum dryer. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the installation of the steam distribution device of the membrane drum dryer in a specific embodiment of the present invention; Figure 2 This is a cross-sectional view of the stamped disc in a specific embodiment of the present invention; Figure 3 This is a partial cross-sectional view illustrating the first connector and the plug plate in a specific embodiment of the present invention; Figure 4 for Figure 3 Enlarged view of region A in the middle; Figure 5 This is a partial schematic diagram of a membrane drum dryer according to a specific embodiment of the present invention.

[0021] In the diagram: 1. Steam distribution device for membrane drum dryer; 11. Disc tube; 111. Straight pipe section; 112. Conical pipe section; 113. Welded section; 114. Beveled surface; 12. Connecting steel pipe; 13. Inlet steel pipe; 14. Outlet steel pipe; 15. First steel pipe; 16. Second steel pipe; 17. First joint; 171. First connecting pipe; 1711. Fourth limiting part; 1712. Prismatic ring; 172. Second connecting pipe; 1721. Third limiting part; 173. Connecting sleeve; 1731. First limiting part; 1732. Second limiting part; 1733. Prismatic surface; 174. Sealing ring; 175. Flat surface; 18. Second joint; 19. Blocking plate; 2. Steam main pipe; 3. Heat exchanger pipe; 4. Hole sealing assembly; 5. Cylinder body. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] like Figure 1-5 As shown, in an illustrative embodiment of the membrane drum dryer and its steam distribution device of the present invention, a steam distribution device for the membrane drum dryer is provided, including an expansion unit. The expansion unit has a disc tube 11 formed by welding multiple flying saucer structures in sequence. The flying saucer structure is formed by welding two symmetrical stamped discs. The two stamped discs have tapered tube sections 112 whose diameter gradually decreases from the middle of the flying saucer structure to the end of the flying saucer structure. The diameter of the large diameter end of the tapered tube section 112 is more than twice the diameter of the small diameter end of the tapered tube section 112. The wall thickness of the disc tube 11 is greater than 1 mm.

[0027] When the steam pressure inside the steam distribution device 1 of the membrane drum dryer increases, the saucer structure deforms, increasing its volume to absorb excess steam pressure. When the steam pressure inside the steam distribution device 1 decreases, the saucer structure returns to its original shape and volume, maintaining a certain steam pressure inside the steam distribution device 1.

[0028] Compared to conventional metal bellows, the aforementioned UFO structure features a greater corrugation depth and thicker walls. This design balances its ability to regulate steam pressure through deformation with enhanced structural strength and extended service life. The increased wall thickness improves the UFO structure's pressure-bearing capacity and structural stability, reducing the likelihood of steam leakage in the membrane drum dryer's steam distribution unit 1. The increased corrugation depth compensates for the reduced flexibility due to the increased wall thickness, ensuring the UFO structure's ability to regulate internal steam pressure.

[0029] In some embodiments, the stamping disc consists of a straight pipe section 111, a tapered pipe section 112, and a welded section 113 connected smoothly along its own axis; the diameter of the welded section 113 is equal to the major diameter of the tapered pipe section 112, and a beveled slope 114 is provided on the side of the welded section 113 away from the tapered pipe section 112.

[0030] The straight pipe section 111 is used to reserve axial expansion space for two adjacent flying saucer structures so that the tapered pipe section 112 can undergo axial elastic deformation to absorb and release steam pressure.

[0031] The welded section 113 has a bevel 114, which can significantly increase the penetration and strength of the weld in the middle of the flying saucer structure. At the same time, the bevel 114 can effectively disperse the welding thermal stress, reduce the risk of deformation of the flying saucer structure, and improve the structural reliability of the flying saucer structure.

[0032] In some embodiments, the axis of the disc tube 11 is a straight line; the expansion unit also has a connecting steel pipe 12, and the expansion unit has a plurality of disc tubes 11 arranged in sequence, with a connecting steel pipe 12 welded between two adjacent disc tubes 11.

[0033] The disc tube 11 only expands and contracts in a straight line along its axis, and the steam pressure is evenly distributed along the circumference of the disc tube 11, which avoids local stress concentration that may be caused by bending of the axis of the disc tube 11 and helps to extend the service life of the disc tube 11.

[0034] In some embodiments, when the nominal diameter DN of the straight pipe section 111 is less than 30, the wall thickness of the disc tube 11 is 1.2 mm to 1.5 mm; when the nominal diameter DN of the straight pipe section 111 is greater than 30 and less than or equal to 50, the wall thickness of the disc tube 11 is 1.5 mm to 2.0 mm. These dimensional limitations balance the flexibility and structural reliability of the disc tube 11.

[0035] Furthermore, the length of the straight pipe section 111 is 2mm to 5mm.

[0036] Furthermore, the expansion unit is made of 316L stainless steel, which helps to improve the expansion unit's high temperature resistance, corrosion resistance, and fatigue resistance.

[0037] In some embodiments, the taper of the tapered tube is greater than 45° and less than 90°, so as to convert as much of the steam pressure in the disc tube 11 as possible into the axial expansion pressure of the disc tube 11, thereby achieving a better steam pressure absorption effect.

[0038] Furthermore, the taper of the tapered tube is less than or equal to 70° to reduce stress concentration in the weld seam in the middle of the flying saucer structure, improve the reliability of the flying saucer structure, and extend the service life of the flying saucer structure.

[0039] In some embodiments, an inlet steel pipe 13 and an outlet steel pipe 14 are welded to both ends of the expansion unit, respectively. The steam distribution device 1 of the membrane drum dryer also includes a first steel pipe 15 welded to the heat exchange tube 3 of the membrane drum dryer, a second steel pipe 16 welded to the steam main pipe 2 of the membrane drum dryer, a first joint 17 for detachably sealing the outlet steel pipe 14 and the first steel pipe 15, and a second joint 18 for detachably sealing the inlet steel pipe 13 and the second steel pipe 16. With the above structural arrangement, the inlet steel pipe 13, the expansion unit, and the outlet steel pipe 14 can be disassembled, installed, and replaced on the membrane drum dryer.

[0040] Furthermore, the first steel pipe 15, the second steel pipe 16, the air inlet steel pipe 13, the expansion unit, and the air outlet steel pipe 14 have the same wall thickness and the same minimum inner diameter.

[0041] In some embodiments, the steam distribution device 1 of the membrane drum dryer further includes a blocking plate 19, the outer side of the blocking plate 19 being shaped to match the inner wall of the heat exchange tube 3 and welded to the inner wall of the heat exchange tube 3, and a first steel pipe 15 passing through the blocking plate 19, the outer wall of the first steel pipe 15 being welded to the inner side of the blocking plate 19.

[0042] The blocking plate 19 matches the large diameter of the heat exchange tube 3 with the small diameter of the first steel pipe 15, limiting the diameter of the first steel pipe 15 to a smaller range, reducing the weight of the steam distribution device 1 of the membrane drum dryer, and reducing the possibility that the centrifugal force generated by the steam distribution device 1 of the membrane drum dryer will tear the weld of the steam distribution device 1 of the membrane drum dryer.

[0043] In some embodiments, the axes of the first steel pipe 15 and the second steel pipe 16 are both straight lines; the expansion unit has two disc pipes 11; the inlet steel pipe 13 includes a first bend section and two first straight pipe sections located at both ends of the first bend section; the outlet steel pipe 14 includes a second bend section and two second straight pipe sections located at both ends of the second bend section; the connecting steel pipe 12 includes a third bend section and two third straight pipe sections located at both ends of the third bend section; the disc pipe 11 located between the connecting steel pipe 12 and the outlet steel pipe 14 has a welded third straight pipe section shorter than its welded second straight pipe section.

[0044] The two disc tubes 11 are located near the steam main pipe 2 of the steam distribution device 1 of the membrane drum dryer to quickly buffer the steam pressure fluctuations from the direction of the steam main pipe 2, reduce the impact and disturbance of the steam pressure fluctuations on the heat exchange tube 3, and ensure the reliability of the connection between the steam distribution device 1 and the heat exchange tube 3 of the membrane drum dryer.

[0045] In some embodiments, the first connector 17 and the second connector 18 have the same structure. The first connector 17 includes a first tube 171, a second tube 172, a connecting sleeve 173, and a sealing ring 174. A first limiting portion 1731 is formed on the inner side of the connecting sleeve 173, and a second limiting portion 1732 is formed on the inner side of the first limiting portion 1731. A third limiting portion 1721 is formed on the outer wall of the second tube 172, located inside the connecting sleeve 173. The second tube 172 passes through the first limiting portion 1731 and the second limiting portion 1732, and the third limiting portion 1721 abuts against the second limiting portion 1732 to achieve axial limiting of the second tube 172 on the connecting sleeve 173. The first connector 171 is threadedly connected to the inner wall of the connecting sleeve 173 and abuts against and communicates with the second connector 172; the outer wall of the first connector 171 is formed with a fourth limiting part 1711 located inside the connecting sleeve 173, and the sealing ring 174 is sleeved on the first connector 171 and clamped between the fourth limiting part 1711 and the first limiting part 1731.

[0046] In the above structure, the end of the second connector 172 rotates with the connecting sleeve 173, and the first connector 171 is threadedly connected to the inner wall of the connecting sleeve 173, so as to realize a reliable and quick connection between the first connector 171 and the second connector 172.

[0047] Furthermore, in the first joint, the first connecting pipe is welded to the first steel pipe, and the second connecting pipe is welded to the outlet steel pipe. In the second joint, the first connecting pipe is welded to the second steel pipe, and the second connecting pipe is welded to the inlet steel pipe.

[0048] In some embodiments, the outer walls of the first connector 171 and the second connector 172 outside the connecting sleeve 173 are provided with a plane 175 parallel to themselves to cooperate with a wrench or socket; the outer wall of the first connector 171 is also formed with a fifth limiting part that abuts against the connecting sleeve 173 to limit the depth of the first connector 171 screwed into the connecting sleeve 173, so as to prevent the first connector 171 from being screwed into the connecting sleeve 173 too deeply, reduce the possibility of the sealing ring 174 being crushed, and extend the service life of the sealing ring 174.

[0049] In some embodiments, the outer wall of the first connector 171 is formed with a prism ring 1712 to match a socket or wrench.

[0050] The outer wall of the connecting sleeve 173 is a prism face 1733 to match a socket or wrench.

[0051] like Figure 5As shown, the present invention also provides a membrane drum dryer, including a drum body 5, a steam main pipe 2, heat exchange tubes 3, and a membrane drum dryer steam distribution device 1 as described in any of the above embodiments or combinations thereof; the steam main pipe 2 is installed in the drum body 5; multiple heat exchange tubes 3 are arranged inside the drum body 5, all heat exchange tubes 3 are parallel to the axis of the drum body 5, and each heat exchange tube 3 is connected to the steam main pipe 2 through one of the membrane drum dryer steam distribution devices 1; all membrane drum dryer steam distribution devices 1 do not contact each other, so as to reduce the possibility of the disc tubes 11 of multiple membrane drum dryer steam distribution devices 1 colliding with each other during the rotation of the membrane drum dryer, and extend the service life of the membrane drum dryer steam distribution devices 1.

[0052] In some embodiments, the heat exchange tubes 3 are divided into multiple groups, with multiple heat exchange tubes 3 in each group. The heat exchange tubes 3 in different groups are positioned differently in the radial direction of the film drum dryer. All heat exchange tubes 3 in the same group are evenly distributed around the axis of the film drum dryer. The steam distribution devices 1 of the film drum dryer connected to the heat exchange tubes 3 in different groups are positioned differently in the axial direction of the film drum dryer. The axial distance between two adjacent groups of steam distribution devices 1 is greater than 50 mm and less than 100 mm. The steam distribution devices 1 of the film drum dryer connected to different heat exchange tubes 3 in the same group are positioned differently in the circumferential direction of the film drum dryer. The circumferential distance between two adjacent groups of steam distribution devices 1 in the same group is greater than 100 mm and less than 300 mm.

[0053] In some embodiments, the membrane drum dryer also includes a hole sealing assembly 4 welded to the drum body 5. The hole sealing assembly 4 corresponds one-to-one with the heat exchange tube 3. Each heat exchange tube 3 passes through its corresponding hole sealing assembly 4 and is movably sealed with its corresponding hole sealing assembly 4.

[0054] Through the description of several embodiments of the steam distribution device for the membrane drum dryer of the present invention, it can be seen that the embodiments of the steam distribution device for the membrane drum dryer of the present invention have at least one or more of the following advantages: 1. Compared to conventional metal bellows, the UFO structure in this invention has a greater corrugation depth and wall thickness, ensuring both its ability to regulate steam pressure through deformation and its structural strength, thus extending its service life. The increased wall thickness enhances the pressure-bearing capacity and structural stability of the UFO structure, reducing the likelihood of steam leakage in the steam distribution device of the membrane drum dryer. The increased corrugation depth compensates for the reduced flexibility due to the increased wall thickness, ensuring the UFO structure's ability to regulate internal steam pressure.

[0055] 2. In this invention, the disc tube only expands and contracts in a straight line along the axis, and the steam pressure is evenly distributed along the circumference of the disc tube, which avoids local stress concentration that may be caused by bending of the disc tube axis and helps to extend the service life of the disc tube.

[0056] 3. In this invention, the air inlet steel pipe, the expansion unit, and the air outlet steel pipe can be detachably connected to the main body of the membrane drum dryer through the first joint and the second joint, so as to facilitate the disassembly and replacement of the expansion unit on the membrane drum dryer.

[0057] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A steam distribution device for a membrane drum dryer, characterized in that, It includes an expansion unit, which has a disc tube formed by welding multiple flying saucer structures in sequence; the flying saucer structure is formed by welding two symmetrical stamped discs, and the two stamped discs have tapered tube sections whose diameter gradually decreases from the middle of the flying saucer structure to the end of the flying saucer structure, and the diameter of the large diameter end of the tapered tube section is more than twice the diameter of the small diameter end of the tapered tube section; the wall thickness of the disc tube is greater than 1mm.

2. The steam distribution device for a membrane drum dryer according to claim 1, characterized in that, The stamped disc consists of a straight pipe section, a tapered pipe section, and a welded section that are smoothly connected along its own axis. The diameter of the welded section is equal to the major diameter of the tapered pipe section, and a bevel is provided on the side of the welded section away from the tapered pipe section.

3. The steam distribution device for a membrane drum dryer according to claim 2, characterized in that, When the nominal diameter DN of the straight pipe section is less than 30, the wall thickness of the disc pipe is 1.2mm to 1.5mm; when the nominal diameter DN of the straight pipe section is greater than 30 and less than or equal to 50, the wall thickness of the disc pipe is 1.5mm to 2.0mm.

4. The steam distribution device for a membrane drum dryer according to claim 2, characterized in that, The axis of the disc tube is a straight line; the expansion unit also has a connecting steel pipe. The expansion unit has multiple disc tubes arranged in sequence, and a connecting steel pipe is welded between two adjacent disc tubes.

5. The steam distribution device for a membrane drum dryer according to claim 4, characterized in that, The expansion unit has an inlet steel pipe and an outlet steel pipe welded to its two ends respectively. The steam distribution device of the membrane drum dryer also includes a first steel pipe welded to the heat exchange tube of the membrane drum dryer, a second steel pipe welded to the steam main pipe of the membrane drum dryer, a first joint for detachably sealing the outlet steel pipe and the first steel pipe, and a second joint for detachably sealing the inlet steel pipe and the second steel pipe.

6. The steam distribution device for a membrane drum dryer according to claim 5, characterized in that, It also includes a blocking plate, the outer edge of which matches the shape of the inner wall of the heat exchange tube and is welded to the inner wall of the heat exchange tube. A first steel pipe passes through the blocking plate, and the outer wall of the first steel pipe is welded to the inner edge of the blocking plate.

7. The steam distribution device for a membrane drum dryer according to claim 5, characterized in that, The first connector and the second connector have the same structure. The first connector includes a first connecting pipe, a second connecting pipe, a connecting sleeve, and a sealing ring. A first limiting part is formed on the inner side of the connecting sleeve, and a second limiting part is formed on the inner side of the first limiting part. A third limiting part is formed on the outer wall of the second connecting pipe, located inside the connecting sleeve. The second connecting pipe passes through the first limiting part and the second limiting part, and the third limiting part abuts against the second limiting part. The first connecting pipe is threaded to the inner wall of the connecting sleeve and abuts against and communicates with the second connecting pipe. A fourth limiting part is formed on the outer wall of the first connecting pipe, located inside the connecting sleeve. The sealing ring is sleeved on the first connecting pipe and clamped between the fourth limiting part and the first limiting part.

8. The steam distribution device for a membrane drum dryer according to claim 7, characterized in that, The outer walls of both the first and second connecting pipes, located outside the connecting sleeve, are provided with planes parallel to themselves to accommodate a wrench or socket; the outer wall of the first connecting pipe is also formed with a fifth limiting part that abuts against the connecting sleeve.

9. A membrane drum dryer, characterized in that, It includes a cylinder, a steam main, heat exchange tubes, and a steam distribution device for a membrane drum dryer as described in any one of claims 1-8; the steam main is installed in the cylinder; multiple heat exchange tubes are arranged inside the cylinder, all of which are parallel to the axis of the cylinder, and each heat exchange tube is connected to the steam main through one of the steam distribution devices for the membrane drum dryer; all the steam distribution devices for the membrane drum dryer do not contact each other.

10. The membrane drum dryer according to claim 9, characterized in that, The heat exchange tubes are divided into multiple groups, with multiple heat exchange tubes in each group. The heat exchange tubes in different groups are positioned differently in the radial direction of the film drum dryer. All heat exchange tubes in the same group are evenly distributed around the axis of the film drum dryer. The steam distribution devices of the film drum dryer connected to the heat exchange tubes in different groups are positioned differently in the axial direction of the film drum dryer. The axial distance between two adjacent groups of steam distribution devices is greater than 50 mm and less than 100 mm. The steam distribution devices of the film drum dryer connected to different heat exchange tubes in the same group are positioned differently in the circumferential direction of the film drum dryer. The circumferential distance between two adjacent groups of steam distribution devices in the same group is greater than 100 mm and less than 300 mm.

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