Steam generating device

Abstract

Disclosed is a steam generating device, comprising: a housing; the heat exchange unit is arranged in the shell; the heat exchange unit comprises a plurality of heat exchange pipes which are arranged in parallel in the circumferential direction; a combustion space is defined by the interiors of the multiple heat exchange pipes. The combustor extends into the combustion space; the smoke outlet is formed in the shell; the air uniformizing structure is arranged between the heat exchange unit and the shell; the air uniformizing structure comprises a blocking part for blocking flue gas and a hole part for allowing the flue gas to pass through; wherein the hole area proportion of the unit area of the area, corresponding to the smoke exhaust port in the radial direction, of the smoke exhaust port is smaller than the hole area proportion of the unit area of other areas.

Description

Technical Field

[0001] The present disclosure relates to the technical field of steam generation, and particularly to a steam generation device. Background Art

[0002] The description in this part only provides background information related to the disclosure of this specification and does not constitute prior art.

[0003] Under the call of national energy conservation and emission reduction, steam generation devices are accelerating towards the development of high-efficiency and low-emission fully premixed condensing type. In particular, the inspection-free / declaration-free cross-flow gas steam generator has a faster steam generation speed compared to traditional steam boilers, is more energy-saving and environmentally friendly, and does not require inspection declaration and annual boiler inspection. It is widely favored by the market and is widely used in national production and life, such as hotels, guesthouses, food processing, textiles, chemicals, feed processing and other industries.

[0004] However, the inspection-free cross-flow gas steam generators on the existing market generally have an excessive actual water volume. In the latest "Boiler Safety Technical Code", the calculation method of the water volume of small steam boilers is clearly defined, that is, the total geometric volume inside the inlet and outlet of the steam-water pressure-bearing system. Based on this calculation method, the water volume of the vast majority of small steam boilers on the existing market far exceeds 30 liters, which not only does not meet the inspection-free standard, but also the installed condensing heat exchanger inside the equipment, as a pressure-bearing component, has relatively high pressure requirements, posing a certain safety hazard.

[0005] In order to obtain an inspection-free steam boiler with a water volume meeting the standard, the applicant applied for the description in the Chinese patent application with the application number 202210081118.6 and the invention name of "New Cross-flow Steam Generator or Steam Boiler and Its Heat Exchange Unit", but it was found that there were problems with poor steam quality and high energy consumption during use. Summary of the Invention

[0006] In response to at least one of the above technical problems, through in-depth research, it is found that: the heat exchange tubes of the cross-flow steam generator or steam boiler are vertically arranged heat exchange tubes distributed circumferentially and are located inside the furnace body, and a rectangular smoke exhaust port is formed on one side of the furnace body, as Figure 12As shown in the figure, the distribution of smoke temperature measured at multiple temperature measurement points around the furnace body can clearly show that the temperature of the heat exchange tube near the smoke outlet is significantly higher than that of the heat exchange tube in other areas. Based on this analysis, the researchers believe that the back pressure on one side of the smoke outlet is lower, so the smoke flow is greater, and more smoke heat is concentrated in the area where the smoke outlet is located, resulting in extremely high temperature in the smoke outlet area. However, unlike the common understanding that the lowest point should be located away from the smoke outlet, the area adjacent to both sides of the smoke outlet is the lowest point in temperature, which not only makes the temperature difference in the circumference of different heat exchange tubes large, but also leads to different vapor-liquid interfaces of different heat exchange tubes, and even the maximum temperature difference is located between adjacent heat exchange tubes, which will aggravate the unstable vapor-liquid interface, and the unstable liquid surface will directly lead to a decrease in steam quality, and will also cause the entire furnace body to operate unstable, bringing certain safety hazards. At the same time, the temperature of the heat exchange tube in the smoke outlet area is obviously too high, which will also easily cause over-temperature failure. After careful investigation, it was found that the damaged areas of the heat exchange tubes were mostly on the inner side and upper section of the heat exchange tubes. After careful research and analysis, it was found that the back pressure on one side of the smoke exhaust port was low, and the smoke not only had a large flow rate but also a fast smoke flow rate. The inner side of the heat exchange tube, as the smoke-facing surface, was constantly in contact with the high-temperature smoke, and the fast-flowing smoke exchanged heat with the inner side of the heat exchange tube and flowed directly to the smoke exhaust port, with less contact and less heat exchange with the back side of the heat exchange tube. Therefore, in this case, the heat exchange area density of the heat exchange tube was low and concentrated on the inner side of the heat exchange tube, resulting in not only high energy consumption of the steam boiler, but also easy over-temperature failure of the inner side of the heat exchange tube. Another reason is that the smoke outlet gap between two adjacent vertical heat exchange tubes is designed to be constant from top to bottom, which makes the resistance of the smoke from top to bottom when passing through the smoke outlet gap basically equal, but the upper section of the heat exchange tube is vaporized water vapor, and the heat absorption capacity of water vapor is poor, which is far lower than the water in the liquid state below, which will cause dry burning damage to the upper section of the heat exchange tube.

[0007] In view of the problem mechanism discovered above, an object of the present disclosure is to provide a steam generating device that can balance the circumferential flue gas flow of the heat exchange tubes, reduce the circumferential temperature difference of the heat exchange tubes, and avoid over-temperature damage to the heat exchange tubes.

[0008] Another object of the present disclosure is to provide a steam generating device that can reduce the energy consumption of steam generation.

[0009] In order to achieve the above objectives, the present invention adopts the following technical solutions: A steam generating device, comprising: case; A heat exchange unit is disposed in the shell; the heat exchange unit comprises a plurality of heat exchange tubes arranged in parallel along the circumferential direction; the plurality of heat exchange tubes are enclosed inside to form a combustion space; a burner extending into the combustion space; A smoke exhaust port disposed on the housing; An air distribution structure disposed between the heat exchange unit and the housing; the air distribution structure includes a blocking portion for blocking the flue gas and a hole portion for allowing the flue gas to pass through; wherein, the area ratio of the hole portion per unit area in the region corresponding to the radial direction of the smoke exhaust port is smaller than the area ratio of the hole portion per unit area in other regions.

[0010] Preferably, in the circumferential direction, the outer side of the heat exchange unit is divided into an air distribution region where the blocking portion is arranged and a vacant region where the blocking portion is not arranged, wherein the area of the air distribution region is at least larger than the area of the smoke exhaust port.

[0011] Preferably, there is a smoke outlet gap between two circumferentially adjacent heat exchange tubes; the blocking portion includes a plurality of blocking members arranged in sequence along the circumferential direction and blocking and arranged downstream of the smoke outlet gap; the hole portion includes gap holes between two circumferentially adjacent blocking members; for two of the gap holes, the circumferential width of the gap hole adjacent to the smoke exhaust port is smaller than the circumferential width of the gap hole far from the smoke exhaust hole; further, a plurality of blocking members are correspondingly arranged downstream of a plurality of smoke outlet gaps, and the circumferential width of the gap hole closest to the smoke exhaust port is the smallest.

[0012] Preferably, the blocking portion includes an air distribution plate fixedly arranged in the air distribution region; the hole portion includes a plurality of air distribution holes arranged on the air distribution plate; the air distribution plate extends along the circumferential direction of the heat exchange unit, and the central angle corresponding in the circumferential direction is less than or equal to 180 degrees, preferably between 120 degrees and 150 degrees.

[0013] Preferably, the width of the air distribution hole is smaller than the minimum width of the smoke outlet gap, and / or the air distribution hole and the smoke outlet gap are staggered in the circumferential direction; preferably, the length direction of the air distribution hole is parallel to the length direction of the heat exchange tube; the plurality of air distribution holes are arranged in an array on the air distribution plate; further, the air distribution plate is provided with a plurality of parallel rows of air holes; each row of air holes includes a plurality of air distribution holes arranged in sequence along the circumferential direction; the air distribution holes in the upper and lower rows are aligned up and down.

[0014] Preferably, in a row of air holes, the width of the air distribution hole in the middle position is the smallest, and the width of the air distribution hole on the outermost side in the circumferential direction is the largest.

[0015] Preferably, the plurality of air distribution holes include a plurality of first air distribution holes and a plurality of second air distribution holes with a width larger than that of the first air distribution holes; wherein, at least two rows of air holes are only composed of long air distribution holes; all short air distribution holes are located above all the rows of air holes only composed of second air distribution holes; preferably, the length of the second air distribution hole is more than twice the length of the first air distribution hole.

[0016] 8. The steam generating device according to claim 1, characterized in that two or more first air distribution holes are arranged in sequence up and down to form a hole unit whose overall length is equal to that of a second air distribution hole, and the distance between two adjacent first air distribution holes above and below is 1 mm to 3 mm.

[0017] Preferably, the width of a single air distribution hole is below 10 mm; specifically, the width range of a single air distribution hole is 1 mm - 6 mm; Optionally, when the width of the air distribution hole is below 3.5 mm, the length of the air distribution hole is below 70 mm. Further, the length of the air distribution hole is 40 to 60 mm; when the width of the air distribution hole is above 3.5 mm, the length of the air distribution hole can be above 70 mm, and preferably the length of the air distribution hole is 90 to 150 mm.

[0018] Preferably, a plurality of smoke guiding members are fixedly arranged outside the heat exchange unit, and the smoke guiding members are arranged radially opposite to the smoke outlet gap; a smoke outlet hole is formed between two adjacent smoke guiding members; preferably, the smoke guiding members are located inside the air distribution structure, and the plurality of smoke guiding members are arranged in one-to-one correspondence with the plurality of smoke outlet gaps.

[0019] Preferably, the smoke guiding member includes a V-shaped smoke guiding plate; the V-shaped smoke guiding plate includes two air guiding plate bodies arranged at an included angle; each of the two air guiding plate bodies is close to one of two circumferentially adjacent heat exchange tubes; the V-shaped plate protrudes radially inward into the smoke outlet gap; Preferably, the included angle is an acute angle, and preferably, the included angle is above 40 degrees.

[0020] Preferably, an auxiliary guiding plate is further arranged at the outer end of the air guiding plate body; the included angle between the auxiliary guiding plate and the air guiding plate body is greater than 90 degrees.

[0021] Preferably, the smoke outlet hole is formed between two adjacent auxiliary guiding plates; the width of the air distribution hole is smaller than the width of the smoke outlet hole, and, the air distribution hole is arranged radially aligned downstream of the smoke outlet hole; preferably, the width of the smoke outlet hole is 5 - 20 mm. The width of the smoke outlet hole is more than twice the width of the air distribution hole. Beneficial effects

[0022] By adding an air distribution structure, the steam generating device of the present application reduces the smoke outlet at the smoke exhaust port side, making the circumferential temperature difference of the heat exchange unit more uniform. It can not only stabilize the gas-liquid separation interface in the heat exchange tube, but also effectively improve the steam quality, avoid the problem of over-temperature failure of the heat exchange tube at the smoke exhaust port side. Moreover, the smoke in the air distribution area can be blocked by the air distribution structure to a certain extent to reduce the too-fast flow of the smoke, further ensuring sufficient heat exchange between the heat exchange tube and the smoke and reducing energy consumption.

[0023] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the ways in which the principles of the present invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0024] Features described and / or illustrated for one embodiment can be used in the same or similar way in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0025] It should be emphasized that the term "comprising / including" when used herein refers to the presence of features, whole things, steps or components, but does not exclude the presence or addition of one or more other features, whole things, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 is a schematic structural view of a steam generating device according to an embodiment of the present disclosure; Figure 2 is Figure 1 an internal structural view of Figure 3 is Figure 2 a partial three-dimensional structural view of the heat exchange unit and the V-shaped air guiding plate of Figure 4 is Figure 3 a partial enlarged view of Figure 5 is Figure 1 a cross-sectional view of Figure 6 is Figure 5 a partial enlarged view of Figure 7 is Figure 1 a front view of the air distribution plate of Figure 8 is Figure 7 a partial enlarged view of Figure 9 is Figure 2 a view of a partial empty area of Figure 10 is a front view of the air distribution plate according to another embodiment of the present invention; Figure 11 is Figure 10 a partial enlarged view of Figure 12 Yes Figure 2 It is the temperature distribution curve diagram of the heat exchange tube in the embodiment with the air equalizing plate and the comparative example without the air equalizing plate. Specific implementation mode

[0028] In order to enable those skilled in the art of this technology to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0029] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be another element in the middle. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be another element in the middle at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation manner.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the description of the present invention in this specification are only for the purpose of describing specific implementation manners and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] Please refer to Figures 1 to 11 , an embodiment of the present disclosure provides a steam generating device, which is applicable but not limited to an inspection-exempt steam generator or a steam boiler, and its water volume is preferably below 50L.

[0032] In this embodiment, the steam generating device is a once-through steam generator. Specifically, the steam generating device includes a body water inlet for inputting water and a steam generating device (furnace body) provided with a smoke exhaust port 100. The steam generating device is used to heat water to generate steam, and the steam is discharged through a steam outlet 20. Specifically, the steam generating device includes a housing 1, a heat exchange unit 4 located inside the housing 1, and a burner extending into the combustion space formed by the heat exchange unit 4. The upper end of the steam generating device is defined with an upper header 90, and the lower end is defined with a lower header. The heat exchange unit 4 is defined between the upper header 90 and the lower header. The heat exchange unit 4 includes a plurality of vertical heat exchange tubes 40 arranged in a circumferential direction. A steam generation flow path is formed inside the vertical heat exchange tubes 40, and a flue gas flow path is formed outside. The flue gas flow path is communicated with the smoke exhaust port 100. Preferably, the steam generating device is only provided with a single circle of vertical heat exchange tubes 40 to reduce the water volume.

[0033] There is a smoke outlet gap 45 between two circumferentially adjacent heat exchange tubes 40. The flue gas flows from the combustion space to the outside of the heat exchange unit 4 through the smoke outlet gap 45. The heat exchange tubes 40 can be smooth tubes or threaded tubes. In this embodiment, heat exchange fins are further provided outside the heat exchange tubes 40 to form fin tubes. The smoke outlet gap 45 is the gap between the tube walls of two circumferentially adjacent heat exchange tubes 40 (excluding fins).

[0034] In this embodiment, a smoke exhaust port 100 is provided on the side wall of the housing 1, and the smoke exhaust port 100 is rectangular. Along the length direction of the heat exchange tubes 40 (also the up and down direction or the vertical direction), the length of the smoke exhaust port 100 is more than one-half and less than four-fifths of the length of the heat exchange tubes 40. Or, the upper height of the smoke exhaust port 100 is between more than one-half and less than four-fifths of the height of the heat exchange tubes 40. The lower end of the smoke exhaust port 100 is generally flush with the lower end of the heat exchange tubes 40. The central angle γ covered by the smoke exhaust port 100 is between 30 degrees and 60 degrees.

[0035] The burner is a cylindrical burner. The burner is fixedly arranged at the lower end of the furnace body. The burner extends into the furnace body and is sleeved inside the heat exchange unit 4. A plurality of heat exchange tubes 40 surround the outside of the burner. One end (generally the lower end) of the burner is connected to a fan, and the fan is connected to a gas valve. The upper end of the burner is flush with the upper end of the smoke exhaust port 100. Some of the heat exchange tubes 40 are higher than the burner and the smoke exhaust port 100, so that a liquid phase section and a steam section are formed in the heat exchange tubes 40. The fan has a gas inlet and an air inlet. The air inlet is connected to a filter, and the gas inlet is connected to a gas valve. An ignition component such as an ignition needle for igniting the burner and a flame detector such as a flame probe for detecting the flame of the burner are also provided in the steam generating device. The ignition component and the flame detector are fixedly installed on the bottom plate of the combustion space.

[0036] To balance the circumferential temperature of multiple heat exchange tubes 40 of the heat exchange unit 4, a uniform air distribution structure is further provided between the heat exchange unit 4 and the housing 1. The uniform air distribution structure can increase the flow resistance of the flue gas, but does not impede the outflow of the flue gas. Specifically, the uniform air distribution structure includes a blocking portion for blocking the flue gas and a hole portion for allowing the flue gas to pass through; wherein, the ratio of the hole area per unit area in the region corresponding to the radial direction of the smoke outlet is smaller than the ratio of the hole area per unit area in other regions. The ratio of the hole area per unit area in the region corresponding to the radial direction of the smoke outlet is calculated as follows: taking the total area of the heat exchange unit region corresponding to the smoke outlet along the radial direction as S1, and the total area of the hole portions in this region as S2, the ratio of the hole area per unit area is: S2 / S1. The ratio of the hole area per unit area in other regions can be calculated in the same way, which will not be elaborated here.

[0037] Among them, the blocking portion at least blocks the smoke exhaust in the region of the heat exchange unit 4 facing the smoke outlet 100 along the radial direction, increasing the flow resistance of the flue gas in this region. The blocking portion of the uniform air distribution structure can extend the flow path of the flue gas flowing from the heat exchange unit 4 to the smoke outlet 100, thereby increasing the flue gas resistance and forcing more flue gas to flow towards the hole portion. Moreover, the flue gas in the uniform air distribution region can be slowed down to a certain extent due to the blocking of the uniform air distribution structure, further ensuring sufficient heat exchange between the heat exchange tubes 40 and the flue gas and reducing energy consumption.

[0038] In the circumferential direction, the outer side of the heat exchange unit 4 can be divided into a uniform air distribution region where the blocking portion is arranged and a vacant region where the blocking portion is not arranged. Both the uniform air distribution region and the vacant region are circumferentially continuous regions on the outer side of the heat exchange unit 4. That is, the circumferential outer side of the heat exchange unit 4 is divided into two regions: the uniform air distribution region and the vacant region. The hole portion includes a plurality of uniform air holes 20 arranged in the uniform air distribution region and a continuous gap 23 arranged in the vacant region. At this time, the region between the two circumferential ends of the uniform air distribution region is the vacant region, which is also the continuous gap 23 of the vacant region. Therefore, the existence of the vacant region does not block the smoke exhaust.

[0039] Compared with the vacant region, the uniform air distribution region is closer to the smoke outlet 100. The uniform air distribution region is adjacent to the smoke outlet 100, and the vacant region is far from the smoke outlet 100. More specifically, the vacant region faces away from the smoke outlet 100, and the uniform air distribution region faces the smoke outlet 100. The smoke outlet 100 is centered and aligned with the uniform air distribution region. The area of the region where the blocking portion is arranged (coverage) does not exceed half of the circumferential area of the heat exchange unit 4. That is, with the center line of the heat exchange unit 4 as the center of the circle, the central angle θ corresponding to the region where the blocking portion is arranged (uniform air distribution region) does not exceed 180 degrees.

[0040] The uniform air flow region has a blocking part added compared to the vacant region. Among them, due to the addition of the blocking part in the uniform air flow region, the smoke exhaust resistance is relatively greater. Correspondingly, more flue gas can be forced to flow towards the vacant region, thus preventing more heat of the flue gas from concentrating in the region where the smoke exhaust port 100 is located, reducing the temperature of the heat exchange tubes 40 near the smoke exhaust port 100, and balancing the circumferential temperature difference of the heat exchange tubes 40. As Figure 12 shown, it can be seen that the temperature of the heat exchange tubes 40 directly facing the exhaust port 100 is effectively suppressed and decreased, and the temperature decrease amplitude is even more than 20 degrees Celsius. The temperatures of the heat exchange tubes 40 in the regions near the two circumferential sides of the exhaust port 100 are also effectively increased, and the increase amplitude is basically more than 10 degrees Celsius. In this way, the temperature difference that was originally about 50 degrees Celsius drops to less than 30 degrees Celsius. Therefore, by adding a uniform air flow structure, the circumferential temperature difference of the heat exchange unit 4 can be effectively made uniform, the steam quality can be effectively improved, and the problem of over-temperature failure of the heat exchange tubes 40 on the side of the smoke exhaust port 100 can be avoided.

[0041] The uniform air flow structure is provided with uniform air holes 20. The width of the uniform air holes 20 is smaller than the minimum width L2 of the smoke outlet gap 45, and / or the uniform air holes 20 and the smoke outlet gap 45 are staggered in the circumferential direction. The flue gas flowing through the smoke outlet gap 45 is blocked by the uniform air flow structure and then discharged through the uniform air holes 20 of the uniform air flow structure. The uniform air flow region is a mirror-symmetrical region and extends symmetrically to the two circumferential sides of the smoke exhaust port 100.

[0042] On the uniform air flow region, the number of the uniform air holes 20 is multiple. The shapes and sizes of different uniform air holes 20 may all be different, or may also depend on the region where the uniform air holes 20 are located. The uniform air holes 20 can be slender holes to have a better wind-blocking and air-out effect. Of course, in other embodiments, the uniform air holes 20 can also be a whole long hole continuously extending from top to bottom. The whole long hole may have different widths at different height positions, so as to balance the smoke outlet flow rates at different positions of the heat exchange unit 4.

[0043] As Figure 2As shown, the blocking part includes an air distribution plate fixedly arranged in the air distribution area; the hole part includes a plurality of air distribution holes arranged on the air distribution plate. Of course, in this embodiment, the hole part also includes a continuous gap 23 between the two circumferential ends of the air distribution plate. The air distribution plate 2 is arranged between the heat exchange unit 4 and the smoke exhaust port 100 and is an arc-shaped bent plate. The air distribution plate 2 is a symmetric plate body 31. In the circumferential direction, the air distribution plate 2 symmetrically extends towards the two circumferential sides of the smoke exhaust port 100. The air distribution plate 2 is located inside the housing 1. The air distribution plate 2 at least covers the entire smoke exhaust port 100, and the area of the air distribution plate 2 is larger than the area of the smoke exhaust port 100. A plurality of air distribution holes 20 are provided on the air distribution plate 2, and the flue gas is discharged through the air distribution holes 20 on the air distribution plate 2 and flows towards the smoke exhaust port 100. The plurality of air distribution holes 20 can be discretely distributed on the air distribution plate 2. The air distribution holes 20 are slender holes, and the length direction of the air distribution holes 20 is parallel to the length direction of the heat exchange tubes 40. In the circumferential direction, the length of the air distribution plate 2 is less than half of the circumferential length of the heat exchange unit 4. That is, the central angle θ corresponding to the air distribution plate 2 is less than or equal to 180 degrees. Preferably, the central angle covered by the air distribution plate 2 is between 120 degrees and 150 degrees.

[0044] On the air distribution plate 2, the air distribution holes 20 are arranged in an array. Specifically, the plurality of air distribution holes 20 are arranged in multiple rows, and each row of air distribution holes 20 is arranged in the circumferential direction, and the air distribution holes 20 in the upper and lower rows are aligned vertically. The air distribution plate 2 is provided with a plurality of parallel air hole rows 25; each air hole row 25 includes a plurality of air distribution holes 20 arranged in sequence in the circumferential direction; the air distribution holes 20 in the upper and lower rows are aligned vertically.

[0045] In a wind hole row 25, the width of the air distribution hole 20 in the middle position is the smallest, and the width of the air distribution hole 20 on the outermost side in the circumferential direction is the largest. Of course, in the embodiment where all the air distribution holes 20 have the same width, the air distribution hole 20 in the middle position is also regarded as having the smallest width.

[0046] The plurality of air distribution holes 20 include a plurality of first air distribution holes 21 and a plurality of second air distribution holes 22 with a width greater than that of the first air distribution holes 21. Among them, at least two air hole rows 25 are only composed of the second air distribution holes 22. To further balance the heat of the flue gas received by the heat exchange tubes 40 at different heights, all the first air distribution holes 21 are located above the air hole rows 25 only composed of long air distribution holes 20. That is, the thinner air distribution holes 20 are at a higher height on the air distribution plate 2, suppressing excessive heat exchange between the upper flue gas and the upper part of the heat exchange tubes 40, avoiding the steam section or the area near the steam section from being in a high-temperature operating environment, and reducing the risk of dry burning.

[0047] In Figure 2In the illustrated embodiment, the heat exchange unit 4 has a first portion above the smoke exhaust port 100 and a second portion below the first portion; the height of the second portion is level with the smoke exhaust port 100. The interior of the heat exchange tubes 40 in the first portion generally corresponds to the steam section. In the first portion, the width of the air distribution holes 20 at the middle position is the smallest. The area of the air distribution holes 20 in the first portion gradually increases from the middle position in the circumferential direction towards both ends. On the first portion, the area of a single air distribution hole 20 directly above the smoke exhaust port 100 is smaller than the area of a single air distribution hole 20 directly facing the smoke exhaust port 100 in the radial direction. The area of a single air distribution hole 20 in the first portion is smaller than the area of a single air distribution hole 20 in the second portion. The areas of each of the air distribution holes 20 in the second portion are equal. The widths of different air distribution holes 20 in the second portion are equal.

[0048] As shown in Figures 7 to 9 , a plurality of first air distribution holes 21 are distributed in the first portion, and a partial number of second air distribution holes 22 are also distributed in the first portion. Only the second air distribution holes 22 are distributed in the second portion. By providing the first air distribution holes 21 in the first portion, the resistance to the passage of the flue gas is increased, excessive outflow of the flue gas in the first portion is suppressed, and the heat exchange amount between the flue gas and the steam section of the heat exchange tubes 40 is reduced, effectively avoiding the problem of dry burning damage to the upper ends of the heat exchange tubes 40. At the middle position of the air distribution plate 2, the first air distribution holes 21 are distributed above the second air distribution holes 22.

[0049] As an alternative embodiment, in the second portion, the width of the air distribution hole 20 at the middle position is the smallest. Similarly, the width of the air distribution holes 20 in the second portion gradually decreases from the middle towards both sides, where the gradual decrease can be a step-by-step decrease, or a decrease for every two, etc., not limited to the case of a step-by-step decrease.

[0050] In the embodiment as shown in Figure 10 、 Figure 11 , compared with the previous embodiment, in this embodiment, the first air distribution holes 21 are distributed in more air hole rows 25, thereby more effectively protecting the heat exchange tubes 40 and avoiding dry burning damage problems in the steam section of the heat exchange tubes 40 and its adjacent areas. The upper 3 air hole rows 25 have the first air distribution holes 21, the width of the first air distribution holes 21 in the middle is the smallest, the first air distribution holes 21 in the middle 5 columns have equal widths (widths between 1 and 2.5 mm), followed by 3 columns (a total of 6 columns) with larger widths (widths between 2.5 and 3.5 mm) of the first air distribution holes 21 on both circumferential sides, then 2 columns (a total of 4 columns) with larger widths (widths between 3.5 and 4.5 mm) of the first air distribution holes 21 on both circumferential sides, and the outermost 2 columns (a total of 4 columns) are the second air distribution holes 22 with the largest widths (widths between 5.5 and 7 mm). The lowermost 5 rows are all the second air distribution holes 22 with widths between 5.5 and 7 mm.

[0051] In this embodiment, since the first air distribution hole 21 is too narrow, even a slight deformation will have a great impact on the air passing effect of the first air distribution hole 21. To avoid this problem, the length of the second air distribution hole 22 is more than twice the length of the first air distribution hole 21. Two or more first air distribution holes 21 are arranged in sequence up and down to form a hole unit whose overall length is equal to that of a second air distribution hole 22, and the distance between two adjacent first air distribution holes 21 up and down is 1 mm to 3 mm. The spacer between two first air distribution holes 21 can form a reinforcing rib to strengthen the structural strength of the first air distribution hole 21 so that it is not easily deformed when heated.

[0052] Specifically, the length of a single air distribution hole 20 is between 30 mm and 150 mm. The width of a single air distribution hole 20 is below 10 mm. Specifically, the width range of a single air distribution hole 20 is 1 mm - 6 mm. Among them, when the width of the air distribution hole 20 (hereinafter referred to as the first air distribution hole) is below 3.5 mm, the length of the air distribution hole 20 is below 70 mm, preferably 40 to 60 mm. When the width of the air distribution hole 20 (hereinafter referred to as the long air distribution hole 20) is above 3.5 mm, the length of the air distribution hole 20 can be above 70 mm, preferably 90 to 150 mm.

[0053] Of course, the air distribution structure is not limited to the embodiment of the air distribution plate 2 above. In other embodiments, the blocking part includes a plurality of blocking members arranged in sequence along the circumferential direction and blocking and arranged downstream of the smoke outlet gap 45; the hole part includes the gap holes between two adjacent blocking members along the circumferential direction; among them, for two of the gap holes, the circumferential width of the gap hole adjacent to the smoke exhaust port is smaller than the circumferential width of the gap hole far from the smoke exhaust hole; further, a plurality of blocking members are correspondingly arranged downstream of a plurality of smoke outlet gaps 45, and the circumferential width of the gap hole closest to the smoke exhaust port is the smallest. For example, the blocking member can be an air distribution strip plate or an air distribution rod, which is arranged between two adjacent heat exchange tubes 40 (such as Figure 3 , Figure 4 the position of the V-shaped plate shown). Of course, as an alternative embodiment, the blocking member can also be a V-shaped plate with a similar structure as Figure 3 , Figure 4 . At this time, each smoke outlet gap 45 is correspondingly provided with 1 blocking member, the circumferential widths of two adjacent smoke outlet holes are different, and the circumferential width of the gap hole facing the middle position of the smoke exhaust port is the smallest and gradually widens symmetrically toward both sides of the circumference.

[0054] To prevent the flue gas from flowing too fast and facilitate sufficient heat exchange between the heat exchange tubes 40 and the flue gas, a smoke guiding member 3 is further provided on the back side (outer side) of the heat exchange unit 4 facing the flue gas. A plurality of smoke guiding members 3 are fixedly provided on the outer side of the heat exchange unit 4. The smoke guiding member 3 is located inside the air distribution structure. The smoke guiding member 3 is arranged downstream of the smoke outlet gap 45 and is arranged opposite to the smoke outlet gap 45. The smoke guiding member 3 is arranged upstream of the air distribution structure and is generally located between the air distribution structure and the heat exchange unit 4. The smoke guiding member 3 is generally arranged between two circumferentially adjacent heat exchange tubes 40. The smoke guiding member 3 has a diversion protrusion protruding radially inward. Diversion gaps are respectively formed between the smoke guiding member 3 and the outer side walls of the heat exchange tubes 40 on both sides. When the oncoming flue gas encounters the diversion protrusion, it is blocked and decelerated and is shunted into the diversion gaps on both sides respectively. A plurality of smoke guiding members 3 are arranged in one-to-one correspondence with a plurality of smoke outlet gaps 45; a smoke outlet hole is formed between two adjacent smoke guiding members 3.

[0055] As Figure 4 shown, the smoke guiding member 3 has a symmetrical structure. The smoke guiding member 3 includes a V-shaped plate, and the V-shaped plate includes two air guiding plate bodies 31 arranged at an angle. Each of the two air guiding plate bodies 31 is close to one of the circumferentially adjacent heat exchange tubes 40. The angle is an acute angle. Preferably, the angle is above 40 degrees and below 90 degrees, so that a narrow diversion gap can be formed between the smoke guiding member 3 and the tube wall of the heat exchange tube 40, and the heat exchange area between the flue gas and the heat exchange tube 40 can be increased.

[0056] To ensure the energy consumption reduction effect, the length of the smoke guiding member 3 is equal to the length of the smoke outlet gap 45 (in the up-down direction), which can block the smoke exhaust of the entire smoke outlet gap 45, increase the flue gas flow path, increase the overall smoke exhaust resistance of the heat exchange unit 4, and increase the contact heat exchange area between the flue gas and the heat exchange tubes 40. The length of the smoke guiding member 3 is more than 80% of the length of the heat exchange tubes 40.

[0057] In one embodiment, the inner wall of the smoke guiding member 3 can be attached to the fins to position its position. Each outer end of the plate body 31 also has an auxiliary guiding plate 32. Continuing from the above description, a smoke outlet hole is formed between two adjacent smoke guiding members 30a and 30b, and the smoke outlet hole is located between two adjacent auxiliary guiding plates 32. Through the two auxiliary guiding plates 32, not only the size of the smoke outlet hole is reduced, but also the heat exchange path of the flue gas and the heat exchange tubes 40 can be further extended, and the heat exchange effect between the heat exchange tubes 40 and the flue gas can be further improved.

[0058] By providing the smoke guiding member 3, it can effectively promote the full contact between the flue gas and the heat exchange tubes 40, and avoid the situation that the heat exchange tubes 40 cannot fully absorb the heat of the flue gas due to the too fast flow of the flue gas. Moreover, in the embodiment with the air distribution plate 2, by providing the smoke guiding member 3, the smoke exhaust temperature of the flue gas can be reduced, thereby avoiding the overheating and deformation damage of the air distribution plate 2 and improving the overall service life.

[0059] In this embodiment, the width of the air distribution holes 20 (in the circumferential direction) is smaller than the width L1 of the smoke outlet holes. The plurality of air distribution holes 20 are dispersed on the air distribution plate 2. The air distribution holes 20 are disposed opposite to the downstream of the smoke outlet holes, that is, the air distribution holes 20 are arranged radially aligned with the downstream of the smoke outlet holes. By both the air distribution plate 2 and the smoke guiding member 3, the smoke resistance on the side of the smoke exhaust port 100 can be increased, so that...

[0060] Continuing the above description, the air distribution holes 20 extend vertically and are parallel to the smoke outlet holes or the heat exchange tubes 40. The air distribution holes 20 are radially aligned with the smoke outlet holes. The width of the air distribution holes 20 is smaller than the circumferential width L1 of the smoke outlet holes. The width of the smoke outlet holes is above 10 mm. Specifically, the width of the smoke outlet holes is 5 - 20 mm. The width L1 of the smoke outlet holes is more than twice the width of the air distribution holes 20. Preferably, the width L1 of the smoke outlet holes is 3 - 8 times the width of the air distribution holes 20.

[0061] As Figure 2 shown, the length of the smoke guiding member 3 is basically equal to the heat exchange section (main section) of the heat exchange tube 40 and the vertical length of the air distribution holes 20. The smoke guiding member 3 extends upward from the lower header to the upper header 90. An upper annular end plate 95 is fixedly provided at the upper end of the heat exchange unit 4, and a lower annular end plate 96 is fixedly provided at the lower end of the heat exchange unit 4. The plurality of smoke guiding members 3 are evenly distributed in the circumferential direction. The upper ends of the plurality of smoke guiding members 3 are fixedly connected to the upper annular end plate, and the lower ends of the plurality of smoke guiding members 3 are fixedly connected to the lower annular end plate. Specifically, the upper ends of the plurality of smoke guiding members 3 are welded to the upper annular end plate, and the lower ends of the plurality of smoke guiding members 3 are welded to the lower annular end plate. To fix the air distribution plate 2, the two ends of the upper end of the air distribution plate 2 can also be welded to the upper annular end plate and the lower annular end plate respectively. In addition, a plurality of hoop sleeves 7 are sleeved outside the air distribution plate 2. The plurality of hoop sleeves 7 are arranged vertically and sleeved and fixed the air distribution plate 2 and the smoke guiding members 3 in the empty area outside the heat exchange unit 4 together. The plurality of hoop sleeves 7 can also strengthen the structural strength of the air distribution plate 2 and the smoke guiding members 3, avoid deformation due to long-term heating, and extend the service life.

[0062] It should be understood that the above description is for illustrative purposes and not for limitation. By reading the above description, many embodiments and many applications other than the provided examples will be obvious to those skilled in the art. Therefore, the scope of this teaching should not be determined by reference to the above description, but should be determined by reference to the appended claims and the full scope of the equivalents of these claims. For the sake of completeness, all articles and references including patent applications and published announcements are incorporated herein by reference. Omitting any aspect of the subject matter disclosed herein in the foregoing claims is not intended to abandon such subject matter, nor should the inventor be considered not to have considered such subject matter as part of the disclosed inventive subject matter.

Claims

1. A steam generating device, characterized in that: include: case; A heat exchange unit is disposed in the shell; the heat exchange unit comprises a plurality of heat exchange tubes arranged in parallel along the circumferential direction; The interior of the plurality of heat exchange tubes is enclosed to form a combustion space; a burner extending into the combustion space; A smoke exhaust port disposed on the housing; An air distribution structure is arranged between the heat exchange unit and the shell; the air distribution structure includes a blocking portion for blocking smoke and a hole portion for allowing smoke to pass through; wherein the ratio of the hole area per unit area in the area corresponding to the radial direction of the smoke exhaust port is smaller than the ratio of the hole area per unit area in other areas.

2. The steam generating device according to claim 1, characterized in that: In the circumferential direction, the outer side of the heat exchange unit is divided into an air distribution area where the blocking part is arranged and an empty area where the blocking part is not arranged, wherein the area of ​​the air distribution area is at least larger than the area of ​​the smoke exhaust port.

3. The steam generating device according to claim 1, characterized in that: There is a smoke outlet gap between two circumferentially adjacent heat exchange tubes; the blocking portion includes a plurality of blocking members arranged in sequence along the circumferential direction and arranged downstream of the smoke outlet gap; the hole portion includes a gap hole between two circumferentially adjacent blocking members; among the two gap holes, the circumferential width of the gap hole adjacent to the smoke exhaust port is smaller than the circumferential width away from the smoke exhaust port; further, the plurality of blocking members are arranged one by one downstream of the plurality of smoke outlet gaps, and the circumferential width of the gap hole closest to the smoke exhaust port is the smallest.

4. The steam generating device according to claim 1, characterized in that: The blocking portion includes an air equalizing plate fixedly arranged in the air equalizing area; the hole portion includes a plurality of air equalizing holes arranged on the air equalizing plate; the air equalizing plate extends along the circumference of the heat exchange unit, and the corresponding central angle in the circumferential direction is less than or equal to 180 degrees, preferably, between 120 degrees and 150 degrees.

5. The steam generating device according to claim 1, characterized in that: The width of the air balancing hole is smaller than the minimum width of the smoke outlet gap, and / or the air balancing hole and the smoke outlet gap are staggered in the circumferential direction; preferably, the length direction of the air balancing hole is parallel to the length direction of the heat exchange tube; the multiple air balancing holes are arranged in an array on the air balancing plate; further, the air balancing plate is provided with multiple parallel rows of air holes; each row of air holes includes multiple air balancing holes arranged in sequence along the circumferential direction; the upper and lower rows of air balancing holes are aligned up and down.

6. The steam generating device according to claim 1, characterized in that: In a row of air holes, the width of the air balancing hole in the middle is the smallest, and the width of the air balancing hole at the outermost side in the circumferential direction is the largest.

7. The steam generating device according to claim 1, characterized in that: The multiple air balancing holes include multiple first air balancing holes and multiple second air balancing holes whose width is greater than that of the first air balancing holes; wherein at least two air hole rows are composed only of long air balancing holes; all short air balancing holes are located above all air hole rows composed only of second air balancing holes; preferably, the length of the second air balancing holes is more than twice the length of the first air balancing holes.

8. The steam generating device according to claim 1, characterized in that: Two or more first air balancing holes are arranged in sequence vertically to form a hole unit which is equal to a second air balancing hole in length as a whole, wherein the interval between two adjacent first air balancing holes vertically is 1 mm to 3 mm.

9. The steam generating device according to claim 1, characterized in that: The width of a single air balancing hole is less than 10 mm; specifically, the width of a single air balancing hole ranges from 1 mm to 6 mm; Optionally, when the width of the air balancing hole is less than 3.5 mm, the length of the air balancing hole is less than 70 mm, and further, the length of the air balancing hole is 40 to 60 mm; when the width of the air balancing hole is more than 3.5 mm, the length of the air balancing hole may be more than 70 mm, and preferably the length of the air balancing hole is 90 to 150 mm.

10. The steam generating device according to claim 1, characterized in that: A plurality of smoke guides are fixedly provided on the outside of the heat exchange unit, and the smoke guides are arranged radially opposite to the smoke outlet gaps; a smoke outlet hole is formed between two adjacent smoke guides; preferably, the smoke guides are located on the inner side of the wind equalizing structure, and the plurality of smoke guides are arranged one-to-one correspondingly to the plurality of smoke outlet gaps.

11. The steam generating device according to claim 1, characterized in that: The smoke guide member comprises a V-shaped smoke guide plate; the V-shaped smoke guide plate comprises two air guide plate bodies arranged at an angle; the two air guide plate bodies are respectively close to one of two circumferentially adjacent heat exchange tubes; the V-shaped plate protrudes radially inwardly and extends into the smoke outlet gap.

12. The steam generating device according to claim 1, characterized in that: The angle is an acute angle, and preferably, the angle is greater than 40 degrees.

13. The steam generating device according to claim 1, characterized in that: An auxiliary guide plate is also provided at the outer end of the air guide plate body; and an angle between the auxiliary guide plate and the air guide plate body is greater than 90 degrees.

14. The steam generating device according to claim 1, characterized in that: The smoke outlet hole is formed between two adjacent auxiliary guide plates; the width of the air balancing hole is smaller than the width of the smoke outlet hole, and the air balancing hole is radially aligned and arranged downstream of the smoke outlet hole; preferably, the width of the smoke outlet hole is 5-20 mm. The width of the smoke outlet hole is more than twice the width of the air balancing hole.

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