Device for controlling temperature difference of drum wall of gas-fired boiler

Abstract

The invention relates to a device for controlling the temperature difference of a steam drum wall of a gas-fired boiler. The device comprises a steam drum body, a built-in heat exchange system and a steam drainage system, the steam pocket body comprises a steam pocket inner wall and a steam pocket outer wall, an annular heat exchange cavity is formed between the steam pocket inner wall and the steam pocket outer wall, and the built-in heat exchange system comprises an annular distribution header, a heat exchange tube bundle, a heat-conducting medium circulating pump and a plate heat exchanger which are sequentially connected through pipelines and form a closed loop. The heat exchange tube bundle is arranged in the annular heat exchange cavity in a spiral mode, and heat conduction oil circulates in the heat exchange tube bundle and is used for evenly supplying heat to the inner wall of the steam pocket. The steam drainage system collects and utilizes waste steam in the initial starting stage to promote water circulation, and the large temperature difference of the steam pocket wall can be avoided in the initial starting stage and the maintenance process after shutdown.

Description

TECHNICAL FIELD

[0001] The application relates to a device for controlling the wall temperature difference of a gas boiler steam pocket, and belongs to the technical field of steam pocket temperature control. BACKGROUND

[0002] The wall temperature difference of an existing gas boiler changes obviously in the initial starting period and the maintenance process after shutdown. Due to the heat release caused by the steam vaporization in the steam pocket, the temperature of the upper part of the steam pocket is higher than that of the lower part, and the upper wall temperature of the steam pocket is higher than the lower wall temperature. It is difficult to control the wall temperature difference of the upper and lower parts of the steam pocket to be less than 60 DEG C in the initial starting period and the maintenance process after shutdown. Especially when the water temperature of the boiler is too low during the starting process of the unit, it is more difficult to control. In order to prevent the risk of steam pocket leakage caused by the large wall temperature difference of the steam pocket in the initial starting period and the maintenance process after shutdown, a device for controlling the wall temperature difference of the steam pocket in the initial starting period and the maintenance process after shutdown needs to be invented. SUMMARY

[0003] In order to solve the above problems existing in the prior art, the application provides a device for controlling the wall temperature difference of a gas boiler steam pocket, which can avoid a large wall temperature difference of the steam pocket in the initial starting period and the maintenance process after shutdown.

[0004] The technical scheme of the application is as follows:

[0005] A device for controlling the wall temperature difference of a gas boiler steam pocket, comprising a steam pocket body, an internal heat exchange system arranged in the steam pocket body, and a steam drainage system. The steam pocket body comprises an inner wall and an outer wall, and an annular heat exchange cavity is formed between the inner wall and the outer wall. The internal heat exchange system comprises an annular distribution header, a heat exchange pipe bundle, a heat conduction medium circulating pump and a plate heat exchanger which are connected in sequence by pipelines and constitute a closed loop. The heat exchange pipe bundle is arranged in the annular heat exchange cavity in a spiral manner, and heat conduction oil is circulated in the heat exchange pipe bundle to uniformly supply heat to the inner wall of the steam pocket. The steam drainage system collects and utilizes the waste steam in the initial starting period to promote water circulation.

[0006] The annular distribution header is fixedly installed on the top outer side of the steam pocket body, the outlet of the annular distribution header penetrates the outer wall of the steam pocket and is connected with the inlet of the heat exchange pipe bundle. The outlet of the heat exchange pipe bundle penetrates the outer wall of the steam pocket and is connected with the inlet of the heat conduction medium circulating pump. The outlet of the heat conduction medium circulating pump is connected with the inlet of the secondary side of the plate heat exchanger. The outlet of the secondary side of the plate heat exchanger is connected with the inlet of the annular distribution header, and the outlet of the secondary side of the plate heat exchanger is connected with the inlet of the annular distribution header, forming a heat conduction oil circulation channel. The inlet of the primary side of the plate heat exchanger is connected with the outlet pipeline of the boiler feed water pump, and the outlet of the primary side of the plate heat exchanger is connected with the inlet pipeline of the boiler coal economizer.

[0007] The steam diversion system includes a steam collection hood, an ejector, a suction pipe, and a mixed water return pipe. The steam collection hood is fitted onto the outside of the saturated steam outlet pipe at the top of the steam drum body, and the top outlet pipe of the steam collection hood is connected to the high-pressure steam input pipe of the ejector. The ejector includes a contraction nozzle and a mixing chamber, and the inlet end of the contraction nozzle is welded to the end of the high-pressure steam input pipe. A suction port is provided on the side wall of the mixing chamber, and a suction pipe is connected to the suction port. The suction pipe extends vertically downward and penetrates the outer wall of the steam drum to the bottom of the water space inside the steam drum body. The bottom of the mixing chamber is connected to the mixed water return pipe, which penetrates the outer wall of the steam drum and returns to the lower water space of the steam drum body. The outlet direction of the mixed water return pipe faces the central axis of the steam drum body.

[0008] The steam diversion system also includes a pressure balancing device, which includes a pressure stabilizing tank and a micro-pressure regulating valve. The pressure stabilizing tank is connected to the top of the steam collection hood, and the micro-pressure regulating valve is installed at the connection between the pressure stabilizing tank and the steam collection hood. The signal input terminal of the micro-pressure regulating valve is electrically connected to a pressure sensor located inside the steam collection hood.

[0009] The ejector is a venturi tube structure, and the inlet of the water suction pipe is equipped with an anti-vortex filter.

[0010] The system also includes a rotating turbulence system, which comprises a magnetic drive mechanism and a blade assembly. The magnetic drive mechanism includes an outer rotor, an inner rotor, and a rotating motor. The outer rotor is rotatably mounted at the center of the outer side of one end cap of the steam drum body. The inner rotor is rotatably disposed on the inner side of the same end cap of the steam drum body and forms a non-contact magnetic coupling with the outer rotor. The outer rotor is connected to the output shaft of the rotating motor. The blade assembly includes a central rotating shaft and at least three sets of turbulence blades. One end of the central rotating shaft is fixedly connected to the center of the inner rotor, and the other end is supported by a bearing on the inner side of the other end cap of the steam drum body. The turbulence blades are equidistantly distributed along the axial direction of the central rotating shaft.

[0011] The deflector blade is rotatably mounted on a central shaft via a blade shaft. An angle adjustment mechanism is provided inside the deflector blade, comprising a temperature-sensitive bimetallic strip, a transmission link, and an eccentric adjustment shaft. The fixed end of the temperature-sensitive bimetallic strip is fixed to the leading edge of the deflector blade. The free end of the temperature-sensitive bimetallic strip is hinged to one end of the transmission link. The other end of the transmission link is hinged to the eccentric hole in the center of the eccentric adjustment shaft. One end of the eccentric adjustment shaft extends out to form the deflector blade and is fixedly connected to the blade shaft.

[0012] The temperature-sensitive bimetallic strip is equipped with a displacement amplification mechanism, which includes a lever fulcrum shaft and an amplifying lever. The two ends of the lever fulcrum shaft are fixedly installed on the bottom wall inside the spoiler blade through fulcrum seats. The amplifying lever is an L-shaped lever with a fulcrum hole in the middle and is sleeved on the lever fulcrum shaft through a bearing. The end of the short arm of the amplifying lever is connected to the lower end of the transmission connecting rod by a ball joint. The end of the long arm of the amplifying lever is hinged to a thrust connecting rod, which is connected to the eccentric hole of the eccentric adjustment shaft.

[0013] The present invention has the following beneficial effects:

[0014] This invention achieves uniform heating of the inner wall of the steam drum through a ring-shaped distribution manifold of a built-in heat exchange system and a spirally arranged heat exchange tube bundle in conjunction with heat transfer oil circulation. The steam diversion system converts the kinetic energy of waste steam into suction force through an ejector, driving the low-temperature water at the bottom to mix with the steam and then inject it directionally back to the lower part of the steam drum. The rotating turbulence system uses magnetic coupling to drive the turbulence blades, combined with a temperature-sensitive bimetallic strip to autonomously adjust the blade angle of attack. The built-in heat exchange system structurally prevents temperature difference generation, and the heat is evenly distributed axially through the circulation of heat transfer oil in the spiral tube bundle in the jacket. The steam diversion system utilizes the boiler's own waste energy, breaking up the stratification of hot and cold water through ejector mixing and directional injection. The rotating turbulence system avoids dynamic seal risks through magnetic transmission, and, in conjunction with the deformation-linked eccentric adjustment shaft of the bimetallic strip, achieves automatic adjustment of the blade angle of attack according to the local water temperature. This allows the steam drum to actively balance the wall temperature during startup and maintain the water temperature distribution during shutdown, fundamentally suppressing temperature difference stress, extending the service life of the steam drum, and reducing external energy consumption. Attached Figure Description

[0015] Fig. 1 This is a schematic diagram of the overall structure of the present invention;

[0016] Fig. 2 This is a schematic diagram of the internal structure of the ejector of the present invention;

[0017] Fig. 3 This is a side view of the rotating turbulence system of the present invention;

[0018] Fig. 4 This is a schematic diagram of the angle adjustment mechanism of the present invention.

[0019] The reference numerals in the figure are as follows:

[0020] 1. Steam drum body; 11. Steam drum inner wall; 12. Steam drum outer wall; 13. Annular heat exchange chamber; 14. Saturated steam outlet pipe; 21. Annular distribution header; 22. Heat exchange tube bundle; 23. Heat transfer medium circulation pump; 24. Plate heat exchanger; 31. Steam collection hood; 32. Ejector; 33. Suction pipe; 34. Mixed water return pipe; 35. Pressure stabilizing tank; 351. Micro-pressure regulating valve; 321. Contraction nozzle; 322. Mixing chamber; 323. High-pressure steam input pipe; 41. Outer rotor; 42. Inner rotor; 43. Rotating motor; 44. Central rotating shaft; 45. Turbine blades; 451. Blade rotating shaft; 51. Temperature-sensitive bimetallic strip; 52. Transmission connecting rod; 53. Eccentric adjusting shaft; 61. Lever fulcrum shaft; 62. Amplifying lever; 63. Fulcrum seat; 64. Thrust connecting rod. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] Please see Figs. 1 to 4 The invention provides a technical solution:

[0023] The device for controlling the temperature difference of the steam drum wall in this embodiment of the gas boiler includes a steam drum body 1 and an internal heat exchange system and a steam diversion system disposed inside the steam drum body 1. The steam drum body 1 includes an inner wall 11 and an outer wall 12, and an annular heat exchange cavity 13 is formed between the inner wall 11 and the outer wall 12. The internal heat exchange system includes an annular distribution manifold 21, a heat exchange tube bundle 22, a heat transfer medium circulation pump 23, and a plate heat exchanger 24, which are connected in sequence by pipes to form a closed loop. The heat exchange tube bundle 22 is arranged in a spiral manner in the annular heat exchange cavity 13, and heat transfer oil flows in the heat exchange tube bundle 22 to uniformly heat the inner wall 11 of the steam drum. The steam diversion system collects and utilizes the waste steam at the beginning of startup to promote water circulation.

[0024] The annular distribution manifold 21 is fixedly installed on the outer top of the steam drum body 1. The outlet of the annular distribution manifold 21 penetrates the outer wall 12 of the steam drum and connects to the inlet of the heat exchange tube bundle 22. The outlet of the heat exchange tube bundle 22 penetrates the outer wall 12 of the steam drum and connects to the inlet of the heat transfer medium circulation pump 23. The outlet of the heat transfer medium circulation pump 23 is connected to the secondary side inlet of the plate heat exchanger 24. The secondary side outlet of the plate heat exchanger 24 is connected to the inlet of the annular distribution manifold 21, forming a heat transfer oil circulation path. The primary side inlet of the plate heat exchanger 24 is connected to the boiler feedwater pump outlet pipe, and the primary side outlet of the plate heat exchanger 24 is connected to the boiler economizer inlet pipe.

[0025] During the initial startup phase of the boiler, the boiler feedwater is cold, while after ignition, the flame and high-temperature flue gas begin to heat the boiler water. At this time, the lower half of the steam drum body 1 is immersed in the relatively cold boiler water, so the temperature of the lower wall rises very slowly. Meanwhile, the upper half of the steam drum body 1 is in direct contact with the steam generated by the evaporation of the boiler water. The steam condenses into water upon contact with the cold metal wall, releasing a large amount of heat, causing the upper wall temperature to rise rapidly. This results in a significant temperature difference between the upper and lower walls. This temperature difference can cause enormous thermal stress on the material of the steam drum body 1. Over time, or when the temperature difference is too large, this can lead to deformation or even cracking of the steam drum body 1, which is extremely dangerous. Therefore, before or during the initial startup phase of the boiler, the built-in heat exchange system is activated to uniformly heat the steam drum body 1.

[0026] The heat transfer medium circulation pump starts working, pumping a preheated heat transfer oil from the boiler's heat source. The heat transfer oil first enters the annular distribution header 21 at the top of the steam drum body 1, and is then evenly distributed to each heat exchange tube bundle 22. As the heat transfer oil flows through these heat exchange tube bundles 22, its heat is transferred through the tube walls to the inner wall 11 and outer wall 12 of the steam drum. Since these heat exchange tube bundles 22 are evenly distributed throughout the entire annular heat exchange chamber 13, heat is simultaneously and evenly transferred to the upper, lower, and sides of the steam drum body 1, rather than heating only one area. The heat transfer oil that has flowed through the entire jacket and released some heat returns to the plate heat exchanger 24, is reheated by the boiler's heat source, and then begins the next cycle.

[0027] The steam diversion system includes a steam collection hood 31, an ejector 32, a water suction pipe 33, and a mixed water return pipe 34. The steam collection hood 31 is fitted onto the outside of the saturated steam outlet pipe 14 at the top of the steam drum body 1 to collect waste steam that cannot be generated during the initial startup and cannot enter the main steam pipe. The top outlet pipe of the steam collection hood 31 is connected to the high-pressure steam input pipe 323 of the ejector 32. The ejector 32 includes a contraction nozzle 321 and a mixing chamber 322. The inlet end of the contraction nozzle 321 is welded to the end of the high-pressure steam input pipe 323. A water suction port is opened on the side wall of the mixing chamber 322, and a water suction pipe 33 is connected to the water suction port. The water suction pipe 33 extends vertically downward and penetrates the outer wall 12 of the steam drum to the bottom of the water space inside the steam drum body 1. The bottom of the mixing chamber 322 is connected to the mixed water return pipe 34. The mixed water return pipe 34 penetrates the outer wall 12 of the steam drum and returns to the lower water space of the steam drum body 1. The outlet direction of the mixed water return pipe 34 faces the central axis of the steam drum body 1.

[0028] During the initial startup phase, after boiler ignition and before the main steam parameters reach the required levels, there is a relatively long process of temperature and pressure increase. The steam generated during this stage has low pressure, low temperature, and unstable quality, making it unable to enter the main steam pipeline to drive the turbine. In traditional designs, this portion of steam is often simply wasted through a vent valve, resulting in energy loss and noise generation. However, the steam diversion system utilizes the heat and kinetic energy of this waste steam to uniformly heat the steam drum and protect the steam drum body.

[0029] High-pressure steam from the steam collection hood 31 is ejected at extremely high speed from the high-pressure steam input pipe 323 of the ejector 32; this high-speed steam stream enters the mixing chamber 322 after passing through the converging nozzle 321. According to Bernoulli's principle, the extremely high-velocity steam will form a strong low-pressure vacuum zone around it; at this time, this low-pressure vacuum zone is connected to the bottom of the water space inside the steam drum body 1, i.e., the place with the lowest water temperature, through the water suction pipe 33. Because the pressure here is much higher than the pressure in the ejector mixing chamber, the strong pressure difference automatically draws the cold water at the bottom into the mixing chamber 322 of the ejector 32. The drawn-in low-temperature water and the high-speed steam flow meet head-on and collide violently in the mixing chamber 322. The high-speed steam impacts the low-speed water flow, accelerating it. Then, the high-temperature steam comes into direct contact with the low-temperature water, instantly transferring most of the heat to the cold water. The phase change releases a large amount of latent heat, resulting in extremely high heating efficiency, while part of the steam itself condenses into water. Finally, they merge into a mixed water flow with a moderate temperature and increased pressure. This mixed water flow is ejected from the mixed water return pipe 34 of the ejector 32 and guided back to the water space at the bottom of the steam drum body 1. This jet powerfully agitates and propels the water at the bottom, completely breaking down temperature stratification and achieving powerful circulation.

[0030] The steam diversion system also includes a pressure balancing device, which comprises a pressure stabilizing tank 35 and a micro-pressure regulating valve 351. The pressure stabilizing tank 35 is connected to the top of the steam collection hood 31, and the micro-pressure regulating valve 351 is installed at the connection between the pressure stabilizing tank 35 and the steam collection hood 31. The signal input terminal of the micro-pressure regulating valve 351 is electrically connected to a pressure sensor located inside the steam collection hood 31. The purpose of the pressure balancing device is to intelligently regulate and ensure that the amount of collected steam does not affect the normal pressure rise process of the boiler. When the main steam parameters are qualified and the system enters the normal operation stage, this system will automatically shut down, giving the steam passage completely to the main steam system.

[0031] During the initial startup phase, the main steam valve of the saturated steam outlet pipe 14 is closed because the steam pressure and quality are not yet sufficient to reach the saturated steam outlet pipe 14. All steam generated at this time can only flow away through the only open steam collection hood 31. In this stage, this useless waste steam is collected to provide power for promoting water circulation. Once the steam meets the required standards, the boiler pressure increases, the steam quality reaches the required level, and the main steam valve of the saturated steam outlet pipe 14 closes. At this point, most of the steam will choose to travel along the spacious saturated steam outlet pipe 14 to the turbine to perform work, as this is the path of least resistance. The steam collection hood 31 will not close, but because its pipe is relatively narrower than the saturated steam outlet pipe 14, and the ejector 32 generates resistance, only a very small amount of steam will still flow through it. At this time, the pressure balancing device automatically adjusts to ensure that the pressure inside the steam collection hood 31 is consistent with the main pipeline, thereby preventing a large amount of steam from being drawn away and ensuring the smooth flow of the saturated steam outlet pipe 14. Specifically, the pressure stabilizing tank 35 is connected to the top of the steam collection hood 31, and its volume is larger than that of the steam collection hood 31. When the steam pressure inside the steam collection hood 31 rises instantaneously, the excess gas can be temporarily contained in this pressure stabilizing tank 35 to prevent a sharp rise in pressure. When the pressure drops, the gas in the pressure stabilizing tank 35 can be replenished, thus playing a role in buffering and stabilizing the pressure. If the pressure sensor detects that the pressure in the steam collection hood 31 is higher than that in the saturated steam outlet pipe 14, the micro-pressure regulating valve 351 opens slightly to release the excess pressure into the pressure stabilizing tank 35, ensuring that the steam in the main pipeline can pass smoothly without being obstructed by the steam collection hood 31. If the pressure sensor detects that the pressure in the steam collection hood 31 is lower than that in the saturated steam outlet pipe 14, the micro-pressure regulating valve 351 closes slightly to reduce the release and allow the pressure to rise, maintaining consistency with the saturated steam outlet pipe 14.

[0032] The ejector 32 has a venturi tube structure, and the inlet of the suction pipe 33 is equipped with an anti-vortex filter.

[0033] It also includes a rotating turbulence system, which comprises a magnetic drive mechanism and a blade assembly. The magnetic drive mechanism includes an outer rotor 41, an inner rotor 42, and a rotating motor 43. The outer rotor 41 is rotatably mounted at the center of the outer side of one end cap of the steam drum body 1, and the inner rotor 42 is rotatably positioned inside the same end cap of the steam drum body 1, forming a non-contact magnetic coupling with the outer rotor 41. The outer rotor 41 is connected to the output shaft of the rotating motor 43. The blade assembly includes a central rotating shaft 44 and at least three sets of turbulence blades 45. One end of the central rotating shaft 44 is fixedly connected to the center of the inner rotor 42, and the other end is supported by a bearing on the inner side of the other end cap of the steam drum body 1. The turbulence blades 45 are equidistantly distributed along the axial direction of the central rotating shaft 44. The steam drum body 1 is a high-pressure vessel, and it is not permissible to have a shaft hole, otherwise, it will leak and explode. The magnetic drive method of this rotating turbulence system can stir the boiler water through non-contact transmission, promoting the mixing of hot and cold water from the inside, and keeping the water temperature in contact with the steam drum wall of the steam drum body 1 relatively uniform.

[0034] The deflector blade 45 is rotatably mounted on the central shaft 44 via the blade shaft 451. The deflector blade 45 is equipped with an angle adjustment mechanism, which includes a temperature-sensitive bimetallic strip 51, a transmission link 52, and an eccentric adjustment shaft 53. The fixed end of the temperature-sensitive bimetallic strip 51 is fixed to the leading edge of the deflector blade 45. The free end of the temperature-sensitive bimetallic strip 51 is hinged to one end of the transmission link 52. The other end of the transmission link 52 is hinged to the eccentric hole in the middle of the eccentric adjustment shaft 53. One end of the eccentric adjustment shaft 53 extends out of the deflector blade 45 and is fixedly connected to the blade shaft 451.

[0035] A displacement amplification mechanism is provided on the temperature-sensitive bimetallic strip 51. The displacement amplification mechanism includes a lever fulcrum shaft 61 and an amplifying lever 62. The two ends of the lever fulcrum shaft 61 are fixedly installed on the bottom wall inside the spoiler blade 45 through fulcrum seats 63. The amplifying lever 62 is an L-shaped lever with a fulcrum hole in the middle and is sleeved on the lever fulcrum shaft 61 through a bearing. The end of the short arm of the amplifying lever 62 is connected to the lower end of the transmission connecting rod 52 by a ball joint. The end of the long arm of the amplifying lever 62 is hinged to a thrust connecting rod 64, which is connected to the eccentric hole of the eccentric adjustment shaft 53.

[0036] When the local water temperature where the temperature-sensitive bimetallic strip 51 is located rises, the heat is conducted to the temperature-sensitive bimetallic strip 51 through the baffle blade 45. The expansion of the high expansion coefficient metal layer is greater than that of the low expansion coefficient metal layer, causing the temperature-sensitive bimetallic strip 51 to bend towards the low expansion coefficient metal layer side. The transmission linkage 52 drives the amplification lever 62 to amplify the stroke and pushes the eccentric adjustment shaft 53 to rotate, thereby driving the entire baffle blade 45 to rotate around the blade rotation shaft 451 to increase the angle of attack. When the water temperature decreases, the temperature-sensitive bimetallic strip 51 returns to straight, and the blade angle of attack of the baffle blade 45 can be reduced accordingly.

[0037] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A device for controlling the temperature difference of the steam drum wall in a gas-fired boiler, characterized in that: The system includes a steam drum body (1) and an internal heat exchange system and a steam diversion system disposed inside the steam drum body (1). The steam drum body (1) includes an inner wall (11) and an outer wall (12) of the steam drum, and an annular heat exchange cavity (13) is formed between the inner wall (11) and the outer wall (12). The internal heat exchange system includes an annular distribution manifold (21) connected in sequence by pipes to form a closed loop, a heat exchange tube bundle (22), a heat transfer medium circulation pump (23), and a plate heat exchanger (24). The heat exchange tube bundle (22) is arranged in a spiral manner in the annular heat exchange cavity (13), and heat transfer oil flows in the heat exchange tube bundle (22) to uniformly heat the inner wall (11) of the steam drum. The steam diversion system collects and utilizes the waste steam at the beginning of startup to promote water circulation.

2. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 1, characterized in that: The annular distribution manifold (21) is fixedly installed on the outer top of the steam drum body (1). The outlet of the annular distribution manifold (21) penetrates the outer wall (12) of the steam drum and is connected to the inlet of the heat exchange tube bundle (22). The outlet of the heat exchange tube bundle (22) penetrates the outer wall (12) of the steam drum and is connected to the inlet of the heat transfer medium circulation pump (23). The outlet of the heat transfer medium circulation pump (23) is connected to the secondary side inlet of the plate heat exchanger (24). The secondary side outlet of the plate heat exchanger (24) is connected to the inlet of the annular distribution manifold (21). The secondary side outlet of the plate heat exchanger (24) is connected to the inlet of the annular distribution manifold (21), forming a heat transfer oil circulation path. The primary side inlet of the plate heat exchanger (24) is connected to the boiler feedwater pump outlet pipe, and the primary side outlet of the plate heat exchanger (24) is connected to the boiler economizer inlet pipe.

3. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 1, characterized in that: The steam diversion system includes a steam collection hood (31), an ejector (32), a water suction pipe (33), and a mixed water return pipe (34); the steam collection hood (31) is fitted around the saturated steam outlet pipe (14) at the top of the steam drum body (1), and the outlet pipe of the steam collection hood (31) is connected to the high-pressure steam input pipe (323) of the ejector (32); the ejector (32) includes a converging nozzle (321) and a mixing chamber (322), and the inlet end of the converging nozzle (321) is connected to the high-pressure steam input pipe (34). 23) End welding connection; the side wall of the mixing chamber (322) is provided with a water suction port, and the water suction port is connected to a water suction pipe (33); the water suction pipe (33) extends vertically downward and penetrates the outer wall (12) of the steam drum to the bottom of the water space inside the steam drum body (1). The bottom of the mixing chamber (322) is connected to the mixed water return pipe (34). The mixed water return pipe (34) penetrates the outer wall (12) of the steam drum and returns to the lower water space of the steam drum body (1). The outlet direction of the mixed water return pipe (34) is towards the central axis of the steam drum body (1).

4. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 3, characterized in that: The steam diversion system also includes a pressure balancing device, which includes a pressure stabilizing tank (35) and a micro-pressure regulating valve (351). The pressure stabilizing tank (35) is connected to the top of the steam collection hood (31). The micro-pressure regulating valve (351) is installed at the connection between the pressure stabilizing tank (35) and the steam collection hood (31). The signal input terminal of the micro-pressure regulating valve (351) is electrically connected to a pressure sensor located inside the steam collection hood (31).

5. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 4, characterized in that: The ejector (32) has a venturi tube structure, and the inlet of the water suction pipe (33) is provided with an anti-vortex filter.

6. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 1, characterized in that: It also includes a rotating turbulence system, which includes a magnetic drive mechanism and a blade assembly. The magnetic drive mechanism includes an outer rotor (41), an inner rotor (42), and a rotating motor (43). The outer rotor (41) is rotatably mounted on the outer center of one end cap of the steam drum body (1). The inner rotor (42) is rotatably disposed on the inner side of the same end cap of the steam drum body (1) and forms a non-contact magnetic coupling with the outer rotor (41). The outer rotor (41) is connected to the output shaft of the rotating motor (43). The blade assembly includes a central rotating shaft (44) and at least three sets of turbulence blades (45). One end of the central rotating shaft (44) is fixedly connected to the center of the inner rotor (42), and the other end is supported by a bearing on the inner side of the other end cap of the steam drum body (1). The turbulence blades (45) are equidistantly distributed along the axial direction of the central rotating shaft (44).

7. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 6, characterized in that: The deflector blade (45) is rotatably mounted on the central shaft (44) via the blade shaft (451). An angle adjustment mechanism is provided inside the deflector blade (45). The angle adjustment mechanism includes a temperature-sensitive bimetallic strip (51), a transmission link (52), and an eccentric adjustment shaft (53). The fixed end of the temperature-sensitive bimetallic strip (51) is fixed to the leading edge of the deflector blade (45). The free end of the temperature-sensitive bimetallic strip (51) is hinged to one end of the transmission link (52). The other end of the transmission link (52) is hinged to the eccentric hole in the middle of the eccentric adjustment shaft (53). One end of the eccentric adjustment shaft (53) extends out of the deflector blade (45) and is fixedly connected to the blade shaft (451).

8. The device for controlling the temperature difference of the steam drum wall in a gas-fired boiler as described in claim 7, characterized in that: The temperature-sensitive bimetallic strip (51) is provided with a displacement amplification mechanism, which includes a lever fulcrum shaft (61) and an amplification lever (62). The two ends of the lever fulcrum shaft (61) are fixedly installed on the bottom wall inside the turbulence blade (45) through fulcrum seats (63). The amplification lever (62) is an L-shaped lever. The amplification lever (62) has a fulcrum hole in the middle and is sleeved on the lever fulcrum shaft (61) through a bearing. The end of the short arm of the amplification lever (62) is connected to the lower end of the transmission connecting rod (52) by a ball joint. The end of the long arm of the amplification lever (62) is hinged to a thrust connecting rod (64), which is connected to the eccentric hole of the eccentric adjustment shaft (53).

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