Train dry-burning prevention three-phase instant heating pipe

Abstract

The application relates to a dry-burning-preventing three-phase instant heating pipe for a train, which comprises a pipe body, the pipe body is vertically arranged, a plurality of heat exchange pipes are arranged in the pipe body, water inlet pipes are arranged in the heat exchange pipes, the bottom ends of the water inlet pipes extend to the outside of the pipe body, a water collecting box is arranged between the bottom ends of the water inlet pipes, a water return pipe is arranged between the water collecting box and the bottom of the pipe body, heating wires are arranged between the water inlet pipes and the heat exchange pipes, insulating powder is filled between the heat exchange pipes and the water inlet pipes, first detection parts, second detection parts and third detection parts for preventing dry burning in the pipe body are arranged on the pipe body, and a water outlet communicating with the inside of the pipe body is further arranged on the top of the pipe body. The application has the effects of improving the applicability, safety and maintenance efficiency of the instant heating pipe.

Description

Technical Field

[0001] This application relates to the field of water dispenser technology on high-speed trains, and in particular to a three-phase instant heating tube for trains that prevents dry burning. Background Technology

[0002] With the continuous advancement of high-speed rail technology, the pursuit of superior performance and higher speeds has become a new goal for engineers. Therefore, reducing train weight and increasing passenger capacity have become the core focus of next-generation train development. To maximize seating capacity within a limited space, the volume of internal train facilities such as water heaters and toilets must be reduced. Consequently, minimizing the size of water heaters has become a major trend for future development; correspondingly, the capacity of the water tank inside the water heater also needs to be reduced, ideally avoiding the use of storage tanks and instead adopting an instantaneous heating design.

[0003] The heating element uses instantaneous heating technology to heat water. Instantaneous electric heating technology is a technology that can instantly heat water from cold to a set temperature. Generally, it works by having cold water flow over the surface of an electric heating element, such as a relatively stable thick-film heating element, and heating the cold water through heat exchange. The resistive layer coated on the thick-film heating element can be heated to extremely high temperatures instantly, achieving a rapid water heating effect.

[0004] Chinese Patent CN215637979U discloses an instant heating element with anti-dry-burning capability, comprising a heating element shell, a heating tube and a middle tube inside the heating element shell; the middle tube is located inside the heating tube, forming a U-shaped loop with the heating tube; the heating element shell has a water inlet end communicating with the middle tube. The heating tube and the middle tube form a U-shaped loop, and the heated water flow forms a swirling water path between the heating tube and the middle tube, forming a U-shaped pipe structure with the middle tube, ensuring that the water level in the swirling water path remains constant, preventing dry burning due to insufficient or no water in the swirling water path.

[0005] Regarding the aforementioned technologies, existing technologies utilize a lower integrated water circuit board to circulate water. The water is transported upwards through pipes for initial heating. Upon reaching the top, the water from the two pipes converges and falls from the middle pipe for final heating. After heating, the water is taken out for passengers to collect. However, the heating equipment in existing technologies is an instantaneous type, which heats the water in a short time using a large heating power. The drawback of this design is that even if the water is heated quickly, a certain amount of heat exchange time is still required. Therefore, passengers need to wait for the water to heat up (a few seconds to a dozen seconds) when collecting water, reducing the applicability of instantaneous heating elements. Summary of the Invention

[0006] To improve the applicability of instant heating tubes, this application provides a three-phase instant heating tube for trains that is designed to prevent dry burning.

[0007] This application provides a technical solution for a train anti-dry-burning three-phase instant heating element:

[0008] A train anti-dry-burning three-phase instant heating tube includes a tube body, which is vertically arranged and has several heat exchange tubes inserted through it. A water inlet pipe is inserted through each heat exchange tube, and the bottom end of the water inlet pipe extends to the outside of the tube body. A water collection box is connected between the bottom ends of the several water inlet pipes. A return water pipe is connected between the water collection box and the bottom of the tube body. A heating wire is installed between the water inlet pipe and the heat exchange tube. Insulating powder is filled between the heat exchange tube and the water inlet pipe. A first detection element, a second detection element, and a third detection element are provided on the tube body to prevent the inside of the tube body from burning dry. A water outlet connected to the inside of the tube body is also provided at the top of the tube body.

[0009] By adopting the above technical solution, during heating, water is injected from the top of the inlet pipe and falls into the water collection box. During this process, the heating wire is energized, heating the heating wire and insulating powder, which in turn heats the heat exchange tube and the inlet pipe to initially heat the water. Subsequently, water enters the pipe body through the return pipe, and the water level gradually rises, exchanging heat with the heat exchange tube for a second heating, thus achieving the effect of heating the water. When passengers need water, water re-enters the top of the inlet pipe, at which point the hot water inside the pipe overflows and is discharged from the outlet. The pipe body is located outside the heat exchange tube, forming a water storage area between them. Compared with existing technologies, the pipe body stores more hot water. The heating wire heats the insulating powder, ensuring that the inlet pipe and the heat exchange tube are heated to the same degree. The two heating processes ensure that the water is ready for use, achieving the effect of immediate and continuous hot water access without waiting for the water to heat up. In addition, by installing a water collection box, the water inlet pipe is kept in a straight line. During maintenance, the water in the inlet pipe and inside the pipe body can be drained through the collection box first, and then water can be added to flush the inner wall of the inlet pipe, which facilitates the maintenance and installation of the heating element. Secondly, the water inlet pipe passes through the heat exchange tube, carrying away some of the heat from the insulating powder. At the same time, the water inside the tube exchanges heat with the heat exchange tube, which on the one hand increases the internal pressure strength of the heat exchange tube, and on the other hand improves the safety of the heating wire temperature rise when energized, thus improving the applicability, safety and maintenance efficiency of the instant heating element.

[0010] Optionally, the water collection box includes a connecting circular plate, a connecting cover plate, and a sealing ring. The connecting circular plate is connected between the bottoms of a plurality of the water inlet pipes, and the return water pipe is connected between the connecting circular plate and the bottom end of the pipe body. The connecting cover plate is disposed below the connecting circular plate, and a drain outlet is provided at the bottom end of the connecting cover plate. A plugging component for sealing water is provided at the drain outlet. The sealing ring is disposed between the connecting circular plate and the connecting cover plate, and a connecting component for restricting the connecting cover plate is provided on the connecting circular plate.

[0011] By adopting the above technical solution, the connecting cover plate is connected to the connecting round plate through the connector, and the sealing ring is used to improve the sealing between the connecting round plate and the connecting cover plate, thus realizing the detachable effect of the water collection box and facilitating the internal maintenance of the water inlet pipe.

[0012] Optionally, a baffle is provided between the water inlet pipe and both ends of the pipe body, the baffle covering the heat exchange pipe, and the baffle being made of ceramic material.

[0013] By adopting the above technical solution, the baffle seals the inside of the heat exchange tube to limit the position of the heating wire pins, so that the heating wire pins are centered and avoid direct contact with the water inlet pipe or the tube body. On the one hand, this reduces the possibility of the heating wire directly contacting the water inlet pipe or the tube body and conducting electricity, and on the other hand, it facilitates the subsequent power connection of the heating tube.

[0014] Optionally, a conductive sheet is provided on the retaining sleeve, and a U-shaped sheet is connected to the conductive sheet, with the end of the heating wire located between the conductive sheet and the U-shaped sheet.

[0015] By adopting the above technical solution, the heating wire is externally energized through the conductive sheet, and the U-shaped sheet is used to further stabilize the heating wire, reducing the possibility of the heating wire detaching from the conductive sheet due to local melting at high temperature.

[0016] Optionally, the first detection element is a detection electrode, which is vertically inserted through the top of the tube, with the detection end of the first detection element located inside the tube, and the first detection element is electrically connected to the water dispenser control system.

[0017] By adopting the above technical solution, when water is injected for the first time, the heating wire does not work. When the water level inside the pipe rises to the detection end of the first detection element, the first detection element sends an electrical signal to the control system, causing the control system to stop the external water supply and turn on the heating wire to heat the water, thus achieving the first layer of anti-dry burning effect inside the pipe.

[0018] Optionally, the second detection element is a temperature sensor. One of the second detection elements is installed on the side wall of the tube body at a position corresponding to a plurality of heat exchange tubes. The detection end of the second detection element faces the heat exchange tube. The second detection element is electrically connected to the water dispenser control system.

[0019] By adopting the above technical solution, if there is no water inside the tube, the heating wire is continuously energized. Through the heat exchange tube of the insulating powder, the air inside the tube near the heat exchange tube is heated to the specified temperature. Then, the second detection element sends an electrical signal to the control system, which controls the external water source to inject water, thereby achieving the second layer of anti-dry burning effect inside the tube.

[0020] Optionally, the third detection element is a pressure-type thermostat. A heat transfer sleeve is connected to the inner top wall of the tube body at a position corresponding to the positions between several heat exchange tubes. A heat transfer cavity is provided inside the heat transfer sleeve. The third detection element is installed on the top of the tube body, and the detection end is located in the heat transfer cavity. A copper tube is connected between the third detection element and its detection end. The copper tube passes through the top of the tube body. The detection temperature of the third detection element is higher than the detection temperature of the second detection element. The third detection element is electrically connected to the water dispenser control system.

[0021] By adopting the above technical solution, if the external water injection function fails, the heating wire inside the tube will continue to heat up, causing the surface temperature of the heat exchange tube to rise to the specified temperature (greater than the detection temperature of the second detection element). Heat will be transferred to the detection end of the third detection element through the heat transfer sleeve. The third detection element will send an electrical signal to the control system, causing the control system to cut off the power to the heating wire, thus achieving the final anti-dry burning effect inside the tube.

[0022] Optionally, a limiting plate is connected to the top of the tube body, the limiting plate has a limiting hole, and the limiting plate has a notch communicating with the limiting hole, and the copper tube is located inside the limiting hole.

[0023] By adopting the above technical solution, the limiting plate is used to help limit the third detection component from coming out of the heat transfer sleeve body, thus avoiding the possibility that the third detection component will displace due to long-term vibration during train operation, causing the detection end of the third detection component to come out of the heat transfer sleeve and resulting in the failure of the anti-dry burning function.

[0024] Optionally, the heat transfer sleeve has several notches on its surface, and the notches are spaced apart along the length of the heat transfer sleeve.

[0025] By adopting the above technical solution, the heat transfer jacket itself is made of a metal material with a high thermal conductivity. However, metal materials have a certain heat storage capacity. Normally, the water temperature will not continue to rise after boiling, but the heat transfer jacket will continue to rise abnormally due to the influence of the hot water temperature. Since the contact area between the heat transfer jacket and the water is limited to the part not in contact with the heat exchange tube, there is a possibility that the heat transfer jacket will continue to heat up, causing its temperature to exceed the actual water temperature, resulting in a decrease in the detection accuracy of the third detection element. By setting a notch, the contact area between the heat transfer jacket and the water is increased, allowing more heat to be absorbed by the water per unit time. This ensures that the temperature of the heat transfer jacket matches the water temperature, improving the detection accuracy of the third detection element and preventing the heating wire from cutting off power due to excessively high heat transfer jacket temperature in the presence of water.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. During heating, water is injected from the top of the inlet pipe and falls into the collection box. During this process, the heating wire is energized, heating the heating wire and insulating powder, which in turn heats the heat exchange tube and inlet pipe, initially heating the water. Subsequently, water enters the pipe body through the return pipe, gradually rising in level and exchanging heat with the heat exchange tube for a second heating, achieving the desired effect. When a passenger needs water, water re-enters the top of the inlet pipe, causing hot water inside the pipe to overflow and exit from the outlet. The pipe body is located outside the heat exchange tube, forming a water storage area between them. Compared to existing technologies, the pipe body stores more hot water. The heating wire heats the insulating powder, ensuring the inlet pipe and heat exchange tube are heated to the same degree. This double heating ensures the water is ready for use, enabling immediate and continuous hot water access without waiting for heating time. In addition, by installing a water collection box, the water inlet pipe is kept in a straight line. During maintenance, the water in the inlet pipe and inside the pipe body can be drained through the collection box first, and then water can be added to flush the inner wall of the inlet pipe, which facilitates the maintenance and installation of the heating element. Secondly, the water inlet pipe passes through the heat exchange tube, carrying away some of the heat from the insulating powder. At the same time, the water inside the tube exchanges heat with the heat exchange tube, which on the one hand increases the internal pressure strength of the heat exchange tube, and on the other hand improves the safety of the heating wire temperature rise when energized, thus improving the applicability, safety and maintenance efficiency of the instant heating element. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the instant heating tube in the embodiment of this application.

[0029] Figure 2 This is a cross-sectional view used in the embodiments of this application to illustrate the internal structure of the tube.

[0030] Figure 3 This is a schematic diagram of the installation structure of the heating wire in an embodiment of this application.

[0031] Figure 4 This is an exploded view used in the embodiments of this application to illustrate the structure of the water collection box.

[0032] Figure 5 This is a cross-sectional view used in the embodiments of this application to illustrate the structure of the first and fourth detection elements.

[0033] Figure 6 This is a schematic diagram of the structure of the third detection element and the limiting plate in the embodiments of this application.

[0034] Explanation of reference numerals in the attached drawings: 1. Pipe body; 11. Heat exchange tube; 12. Outlet; 13. Heat transfer jacket; 14. Limiting plate; 141. Limiting hole; 142. Notch; 15. Fourth inspection piece; 16. Return water pipe; 2. Inlet water pipe; 21. Baffle; 22. Conductive sheet; 23. U-shaped sheet; 24. Heating wire; 3. Water collection box; 31. Connecting round plate; 32. Connecting cover plate; 321. Blocking piece; 33. Sealing ring; 34. Connecting piece; 4. First inspection piece; 5. Second inspection piece; 6. Third inspection piece; 61. Copper pipe. Detailed Implementation

[0035] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0036] This application discloses a three-phase instant heating tube for trains designed to prevent dry burning. (Refer to...) Figure 1 and Figure 2 The train anti-dry-burning three-phase instant heating pipe includes a pipe body 1, which is cylindrical and vertically arranged. Several heat exchange tubes 11 are welded inside the pipe body 1. In this embodiment, three tubes are used as an example. The heat exchange tubes 11 are evenly distributed circumferentially around the pipe body 1. A water outlet 12 that connects to the inside of the pipe body 1 is welded to the top of the pipe body 1.

[0037] Reference Figure 2 and Figure 3 A water inlet pipe 2 is inserted inside the heat exchange tube 11, with a gap between the inner wall of the heat exchange tube 11 and the surface of the water inlet pipe 2. Both ends of the water inlet pipe 2 pass through the tube body 1 and extend to the outside. A retaining sleeve 21, made of ceramic material, is fixedly connected to the water inlet pipe 2 at positions corresponding to both ends of the tube body 1. An installation groove is formed on the retaining sleeve 21, and a conductive sheet 22 is inserted into the groove. A U-shaped sheet 23 is welded onto the conductive sheet 22. A heating wire 24 is disposed between the heat exchange tube 11 and the water inlet pipe 2, welded between the two conductive sheets 22 and located between the conductive sheet 22 and the U-shaped sheet 23. Insulating powder is filled between the heat exchange tube 11 and the water inlet pipe 2; in this embodiment, the insulating powder is magnesium oxide powder.

[0038] Reference Figure 2 and Figure 4A water inlet is installed at the top of the three water inlet pipes 2. A water collection box 3 is set between the bottom ends of the three water inlet pipes 2. The water collection box 3 includes a connecting circular plate 31, a connecting cover plate 32, and a sealing ring 33. The connecting circular plate 31 is welded between the bottom ends of the three water inlet pipes 2, and a return water pipe 16 is welded between the connecting circular plate 31 and the bottom end of the pipe body 1. The connecting cover plate 32 is located below the connecting circular plate 31, and a drain outlet is provided at the bottom end of the connecting cover plate 32. A plug 321 is provided at the drain outlet. The plug 321 is a plug head and is threaded into the drain outlet. The sealing ring 33 is located between the connecting circular plate 31 and the connecting cover plate 32. The sealing ring 33 is made of silicone rubber. A connector 34 is provided between the connecting circular plate 31 and the connecting cover plate 32. The connector 34 is a locking bolt. Several connectors 34 pass through the connecting circular plate 31 and the connecting cover plate 32 and are threaded into the connecting circular plate 31.

[0039] Reference Figure 1 and Figure 5 The pipe body 1 is equipped with a first detection element 4, a second detection element 5, and a third detection element 6. The first detection element 4 is a detection electrode, which is inserted through the top of the pipe body 1, with its sensing end located inside the pipe body 1. The first detection element 4 is electrically connected to the water dispenser control system. During the first water filling, when the water level inside the pipe body 1 reaches the sensing end of the first detection element 4, the control system energizes the heating wire 24.

[0040] Reference Figure 1 and Figure 2 The second detection element 5 is a temperature sensor. A mounting platform is welded to the surface of the tube body 1 at the position corresponding to the heat exchange tube 11. The second detection element 5 is mounted on the mounting platform with its sensing end facing the heat exchange tube 11. The second detection element 5 is electrically connected to the water dispenser control system. When there is no water inside the tube body 1, when the air near the heat exchange tube 11 heats up to the specified temperature, the second detection element 5 sends a signal to the control system to refill with water.

[0041] Reference Figure 2 and Figure 6The third detection element 6 is a pressure-type thermostat, and its detection temperature is higher than that of the second detection element 5. A heat transfer sleeve 13 is welded to the inner top wall of the tube body 1 at the position between the three heat exchange tubes 11. Several notches are formed along the length of the surface of the heat transfer sleeve 13 to increase the heat exchange between the heat transfer sleeve 13 and the water per unit time. A heat transfer cavity is provided inside the heat transfer sleeve 13, which is fitted to the three heat exchange tubes 11. A connecting frame is bolted to the top of the tube body 1, and the third detection element 6 is mounted on the connecting frame. A copper tube 61 is fixedly connected to the third detection element 6, and the detection end of the third detection element 6 is fixedly connected to the bottom of the copper tube 61. The detection end is located inside the heat transfer cavity, and the third detection element 6 is electrically connected to the water dispenser control system. A limiting plate 14 is bolted to the top of the tube body 1. The limiting plate 14 has a limiting hole 141 and a notch 142, with the notch 142 connecting to the limiting hole 141. The copper tube 61 passes through the limiting hole 141. The limiting plate 14 is used to prevent the detection end of the third detection element 6 from detaching from the heat transfer sleeve 13.

[0042] When there is no water inside the tube body 1 and the water supply element fails, the heating wire 24 continues to heat up to the specified temperature, and then transfers the heat to the sensing end of the third detection element 6 through the heat transfer sleeve 13. The third detection element 6 sends an electrical signal to the control system, and the control system cuts off the power to the heating wire 24, thereby achieving the effect of preventing dry burning inside the tube body 1.

[0043] Reference Figure 5 A fourth detection element 15 is also installed at the top of the pipe body 1. The fourth detection element 15 is also a temperature sensor. The fourth detection element 15 is vertically inserted through the top of the pipe body 1, and its sensing end is higher than the sensing end of the first detection element 4. The fourth detection element 15 is electrically connected to the water dispenser control system. The fourth detection element 15 is used to detect the real-time temperature of the water at the water outlet 12.

[0044] The implementation principle of a train anti-dry-burning three-phase instant heating tube in this application embodiment is as follows: During the first water injection, water enters from the inlet and falls into the water collection box 3. Water continues to enter through the return pipe 16 into the tube body 1 until the water surface reaches the sensing end of the first detection element 4. The control system stops the water supply and energizes the heating wire 24. The insulating powder is heated and transfers heat to the heat exchange pipe 11 and the inlet pipe 2 to heat the water inside the inlet pipe 2 and the tube body 1 until the water temperature reaches the specified temperature of the fourth detection element 15, at which point the heating wire 24 is in a heat preservation heating state. When passengers take water, water will be re-injected into the inlet pipe 2 from the outside and initially heated by the heat exchange pipe 11. The hot water inside the tube body 1 is discharged from the outlet 12, and the water inside the inlet pipe 2 enters the tube body 1 for secondary heating, so as to achieve the effect of passengers taking hot water immediately and continuously.

[0045] The tube body 1 is located outside the heat exchange tube 11, forming a water storage area between them. Compared to existing technologies, the tube body 1 stores more hot water. The heating wire 24 heats the insulating powder, ensuring that the inlet pipe 2 and the heat exchange tube 11 are heated to the same degree. This double heating ensures the water is ready for use, achieving both instant and continuous hot water access without waiting for heating time. Furthermore, the water collection box 3 keeps the inlet pipe 2 in a straight line. During maintenance, the water in the inlet pipe 2 and the tube body 1 can be drained through the collection box 3 first, and then water can be added to flush the inner wall of the inlet pipe 2, facilitating maintenance and installation. Secondly, the inlet pipe 2 passes through the heat exchange tube 11, carrying away some heat from the insulating powder. Simultaneously, the water inside the tube body 1 exchanges heat with the heat exchange tube 11, increasing the internal pressure of the heat exchange tube 11 and improving the safety of the heating wire 24 during temperature rise. This enhances the applicability, safety, and maintenance efficiency of the instant heating tube.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A three-phase instant heating tube for trains designed to prevent dry burning, characterized in that: The tube includes a pipe body (1), which is vertically arranged and has several heat exchange tubes (11) inserted through it. A water inlet pipe (2) is inserted through the heat exchange tubes (11), and the bottom end of the water inlet pipe (2) extends to the outside of the pipe body (1). A water collection box (3) is connected between the bottom ends of the several water inlet pipes (2). A return water pipe (16) is connected between the water collection box (3) and the bottom of the pipe body (1). A heating wire (24) is installed between the water inlet pipe (2) and the heat exchange tubes (11). Insulating powder is filled between the heat exchange tubes (11) and the water inlet pipe (2). A first detection element (4), a second detection element (5) and a third detection element (6) are provided on the pipe body (1) to prevent the inside of the pipe body (1) from drying out. An outlet (12) is also provided at the top of the pipe body (1) to connect to the inside of the pipe body (1).

2. The anti-dry-burning three-phase instant heating tube for trains according to claim 1, characterized in that: The water collection box (3) includes a connecting circular plate (31), a connecting cover plate (32), and a sealing ring (33). The connecting circular plate (31) is connected between the bottoms of several water inlet pipes (2). The return water pipe (16) is connected between the connecting circular plate (31) and the bottom end of the pipe body (1). The connecting cover plate (32) is located below the connecting circular plate (31). A drain outlet is provided at the bottom end of the connecting cover plate (32). A plugging component (321) for sealing water is provided at the drain outlet. The sealing ring (33) is located between the connecting circular plate (31) and the connecting cover plate (32). A connecting component (34) for restricting the connecting cover plate (32) is provided on the connecting circular plate (31).

3. The anti-dry-burning three-phase instant heating tube for trains according to claim 2, characterized in that: A baffle (21) is provided between both ends of the water inlet pipe (2) and the pipe body (1). The baffle (21) covers the heat exchange pipe (11) and is made of ceramic material.

4. The anti-dry-burning three-phase instant heating tube for trains according to claim 3, characterized in that: A conductive sheet (22) is threaded through the sleeve (21), and a U-shaped sheet (23) is connected to the conductive sheet (22). The end of the heating wire (24) is located between the conductive sheet (22) and the U-shaped sheet (23).

5. The anti-dry-burning three-phase instant heating tube for trains according to claim 1, characterized in that: The first detection element (4) is a detection electrode. The first detection element (4) is vertically inserted through the top of the tube body (1). The detection end of the first detection element (4) is located inside the tube body (1). The first detection element (4) is electrically connected to the water dispenser control system.

6. The anti-dry-burning three-phase instant heating tube for trains according to claim 1, characterized in that: The second detection element (5) is a temperature sensor. One of the second detection elements (5) is installed on the side wall of the tube body (1) at a position corresponding to a plurality of heat exchange tubes (11). The detection end of the second detection element (5) faces the heat exchange tube (11). The second detection element (5) is electrically connected to the water dispenser control system.

7. The anti-dry-burning three-phase instant heating tube for trains according to claim 1, characterized in that: The third detection element (6) is a pressure-type thermostat. A heat transfer sleeve (13) is connected to the inner top wall of the tube body (1) at a position corresponding to the positions between several heat exchange tubes (11). A heat transfer cavity is provided inside the heat transfer sleeve (13). The third detection element (6) is installed on the top of the tube body (1), and the detection end is located in the heat transfer cavity. A copper tube (61) is connected between the third detection element (6) and its detection end. The copper tube (61) passes through the top of the tube body (1). The detection temperature of the third detection element (6) is higher than the detection temperature of the second detection element (5). The third detection element (6) is electrically connected to the water dispenser control system.

8. The anti-dry-burning three-phase instant heating tube for trains according to claim 7, characterized in that: The top of the tube (1) is connected to a limiting plate (14), the limiting plate (14) has a limiting hole (141), the limiting plate (14) has a notch (142) that communicates with the limiting hole (141), and the copper tube (61) is located inside the limiting hole (141).

9. The anti-dry-burning three-phase instant heating tube for trains according to claim 7, characterized in that: The heat transfer sleeve (13) has several notches on its surface, and the notches are spaced apart along the length of the heat transfer sleeve (13).

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