Heat exchange plate for plate-type air pre-heater and plate-type air pre-heater

Abstract

The utility model discloses a heat exchange plate for a plate-type air pre-heater and the plate-type air pre-heater, belongs to the field of air pre-heaters, overcomes the defect that in the prior art, the cost for adjusting the heat exchange efficiency of a heat exchange plate is high, and mainly adopts the technical scheme that the heat exchange plate for the plate-type air pre-heater is provided. The heat exchange plate is formed by welding two thin plates through a plurality of welding rings which are connected end to end, the non-welded portions of the two thin plates are far away from each other to form an air flowing cavity used for flowing air, the welding rings at least comprise the first welding ring and the second welding ring, the first welding ring and the second welding ring are different in shape, and / or the first welding ring and the second welding ring are different in shape. And the projection areas of the first welding ring and the second welding ring on the heat exchange plate are different. The application is mainly used for reducing the cost of adjusting the heat exchange efficiency of the heat exchange plate.

Description

Technical Field

[0001] This application relates to the field of air preheater technology, and in particular to a heat exchange plate for a plate air preheater and a plate air preheater. Background Technology

[0002] In terms of energy utilization, the exhaust gas from fuel combustion in industrial production carries a large amount of heat energy, which was initially lost due to a lack of effective recovery methods, such as the significant heat loss in traditional boiler flue gas. With the expansion of industrial scale and increased energy awareness, improving energy efficiency has become crucial, leading to the gradual popularization of air preheaters. These preheaters transfer waste heat from exhaust gas to the air through heat exchange, improving combustion efficiency and reducing fuel consumption. Throughout industrial development, air preheaters have evolved from simple tubular structures used in small furnaces to advanced types such as rotary and plate preheaters adapted to the needs of large-scale heavy industries, demonstrating continuous technological innovation. Increasingly stringent environmental requirements have further driven technological advancements in air preheaters, reducing exhaust gas temperature and greenhouse gas emissions, making them important energy-saving and emission-reduction equipment in many industrial sectors. They are widely used and continuously optimized in industries such as power, steel, and chemicals.

[0003] In plate air preheaters, the welding method of the heat exchange plates is relatively fixed, making them unsuitable for certain operating conditions. For example, air preheaters with high heat exchange requirements need relatively high air velocity within the heat exchange plates, while air preheaters with multiple heat exchangers have lower heat exchange requirements and need to reduce the air velocity within the heat exchange plates. Meeting these requirements often necessitates replacing different fans or changing the volume of the heat exchange plates, which increases the cost of the air preheater and its manufacturing. Furthermore, the heat exchange efficiency of existing heat exchange plates is generally consistent. Figures 2 to 3 As shown, the welding rings of heat exchange plates in the prior art are all circular. The way to change the heat exchange efficiency is often to change the thickness of the plate or change the material of the heat exchange plate. On the one hand, this may affect the strength of the heat exchange plate, and on the other hand, it increases the use cost and maintenance cost of the heat exchange plate. Summary of the Invention

[0004] In order to overcome the high cost of adjusting the heat exchange efficiency of heat exchange plates in the prior art, this application provides a heat exchange plate and a plate air preheater for a plate air preheater, which can reduce the cost of adjusting the heat exchange efficiency of heat exchange plates.

[0005] To achieve the above objectives, this application adopts the following technical solution: a heat exchange plate for a plate air preheater, wherein the heat exchange plate is formed by welding two thin plates together with a plurality of weld rings connected end to end, and the unwelded parts of the two thin plates are far apart from each other to form an airflow cavity for flowing air, wherein the weld rings include at least a first weld ring and a second weld ring, the first weld ring and the second weld ring have different shapes, and / or the first weld ring and the second weld ring have different projected areas on the heat exchange plate.

[0006] After adopting the above technical solution, this application has the following advantages: In the prior art, in order to adjust the airflow velocity in the heat exchange plate, it is often necessary to replace different fans or change the volume of the heat exchange plate. However, this solution adjusts the airflow velocity by changing the shape or projected area of ​​the welding ring, eliminating the need for these complex and costly operations. Furthermore, changing the heat exchange efficiency usually involves changing the thickness of the plate or the material of the heat exchange plate, which may affect the strength of the heat exchange plate and increase usage and maintenance costs. This solution mainly adjusts the airflow velocity by using different shapes or projected areas of the welding ring, achieving the same heat exchange efficiency while maintaining the same airflow velocity.

[0007] In this design, only minor structural modifications to the heat exchange plate are needed, reducing its operating cost. Furthermore, the weld rings indirectly enhance the plate's strength, allowing even larger heat exchange plates to function properly. Since the weld rings consist of at least a first and a second weld ring, and their shapes or projected areas differ, this provides various possibilities for adjusting the airflow velocity. The airflow velocity within the air chamber can be controlled by the combination of weld rings according to actual heat exchange requirements. This type of heat exchange plate can be used to adjust the airflow velocity in both air preheaters with high heat exchange efficiency requirements and those with multiple heat exchangers and lower efficiency requirements.

[0008] Furthermore, the shape formed by the welding ring includes teardrop, spindle, wing, rugby ball, rectangle, spindle, or oval.

[0009] Using the aforementioned technical solutions, the welding points in existing technologies are often circular. This shape significantly interferes with airflow within the air chamber, making it difficult to increase the airflow velocity within the heat exchange plate. Replacing them with streamlined shapes such as teardrop or spindle shapes can increase the airflow velocity within the heat exchange plate without compromising its strength, thereby further improving the heat exchange efficiency. For areas requiring reduced airflow velocity, non-streamlined welding ring structures such as rectangles can be selected. The diversity of welding ring shapes allows this heat exchange plate to better adapt to the needs of different industries such as power, steel, and chemicals. Different industries have significantly different requirements for parameters such as airflow velocity and heat exchange efficiency. This type of heat exchange plate with welding rings of various shapes can meet various specific industrial requirements by adjusting the shape combinations, improving the product's versatility across different industries.

[0010] Furthermore, the first and second solder rings form different angles with the airflow direction.

[0011] Using the aforementioned technical solution, weld rings at different angles can break the potential laminar flow state during airflow. In laminar flow, heat exchange between air and the heat exchange plate mainly relies on molecular heat conduction, which is relatively inefficient. However, by changing the angle of the weld rings, turbulence is generated in the air. In turbulent flow, the mixing between hot and cold fluids is more thorough, which can greatly improve the convective heat transfer coefficient, thereby enhancing the heat exchange effect. Besides adjusting the airflow velocity through the shape and projected area of ​​the weld rings, different angles provide a new dimension for adjusting airflow characteristics. Based on actual heat exchange requirements, the velocity distribution and direction of airflow within the airflow chamber can be precisely controlled by changing the angle between the weld rings and the airflow direction, achieving more flexible adjustment of heat exchange efficiency.

[0012] Furthermore, the first welding ring has a hollow design, while the second welding ring has a solid design.

[0013] By adopting the aforementioned technical solution, the design of the first welding ring reduces the overall weight of the heat exchange plate, while the design of the second welding ring increases the thermal conductivity of the heat exchange plate. The combination of the two welding rings can adapt to the needs of various working conditions and find a balance between weight and thermal conductivity.

[0014] Furthermore, adjacent first weld rings are staggered along the airflow direction, and adjacent second weld rings are staggered along the airflow direction.

[0015] Using the aforementioned technical solution, when the first and second welding rings are arranged alternately along the airflow direction, the air will constantly encounter obstacles and change direction as it flows past these rings. This frequent turning and velocity change disrupts the laminar flow state that the air might otherwise exist, promoting turbulence. In turbulent flow, heat exchange between the air and the heat exchange plate mainly occurs through…

[0016] The convection process allows for more thorough mixing of hot and cold fluids, which significantly improves the convective heat transfer coefficient and thus enhances heat transfer efficiency.

[0017] Furthermore, the number of welding rings on the heat exchange plate gradually increases from the air outlet to the air inlet.

[0018] Using the aforementioned technical solution, the air velocity at the air inlet is relatively high, which has a significant impact on the surface strength of the heat exchange plate. By arranging more welding rings, the airflow direction can be regulated and the surface strength of the heat exchange plate can be increased. On the other hand, at the air outlet, the air velocity gradually decreases after passing through several welding rings. Therefore, fewer welding rings are set near the air outlet to balance the requirements of air velocity and plate strength.

[0019] Furthermore, the total projected area of ​​the first welding ring on the heat exchange plate is greater than the total projected area of ​​the second welding ring on the heat exchange plate, the first welding ring is closer to the air inlet, and the second welding ring is closer to the air outlet.

[0020] Using the aforementioned technical solution, near the air inlet, the large projected area of ​​the first welding ring reduces and evenly distributes the airflow velocity, allowing the air more time to exchange heat with the heat exchange plate. According to the principle of convective heat transfer, when the airflow velocity is moderate and evenly distributed, the convective heat transfer coefficient is relatively stable and high, enabling more effective heat transfer from the heat exchange plate to the air. Meanwhile, the small projected area of ​​the second welding ring near the air outlet reduces airflow obstruction. After undergoing the preceding series of heat exchange processes, the air needs to maintain a certain outflow velocity to avoid excessive pressure buildup at the air outlet, ensuring smooth airflow out of the heat exchange plate.

[0021] A plate-type air preheater includes a casing and several heat exchange plates as described above. The heat exchange plates are spaced apart in the casing along the front-to-back direction. The area between two adjacent heat exchange plates is a flue gas passage for flowing flue gas. The upper side of the flue gas passage is the flue gas inlet side, and the lower side is the flue gas outlet side. A plurality of first weld rings in the heat exchange plates form a flow guiding assembly to guide a portion of the air to the upper side of the heat exchange plates.

[0022] By employing the aforementioned technical solution, a portion of the air is guided to the upper part of the heat exchanger plate via a flow guiding component. This allows more air in the airflow chamber to approach the inlet side of the flue gas channel, where the temperature is higher. Consequently, a larger amount of air achieves better heat exchange efficiency. The remaining air exchanges heat with the flue gas on the outlet side below, where the air volume is relatively small, resulting in lower heat exchange requirements. This improves the overall heat exchange efficiency of the heat exchanger plate, achieving a strategy of high-volume heat exchange on the inlet side and normal heat exchange on the outlet side. This ensures a significant reduction in flue gas temperature and a substantial increase in air temperature, saving energy and improving production efficiency.

[0023] Furthermore, the weld ring on the heat exchange plate near the smoke inlet side is spindle-shaped.

[0024] Using the aforementioned technical solution, since the flue gas temperature on the inlet side is relatively high, the welding ring is designed in a spindle shape, which can increase the airflow velocity near the inlet side, achieve rapid heat exchange, and allow a continuous stream of cold air to quickly carry away the temperature of the flue gas.

[0025] Furthermore, the weld ring near the smoke outlet side of the heat exchange plate is rectangular in shape.

[0026] By adopting the aforementioned technical solution, since the flue gas temperature on the exhaust side is relatively low, designing the welding ring into a rectangular shape reduces the air velocity near the exhaust side, thereby increasing the heat exchange time of the air at this point and improving the heat exchange capacity, allowing the flue gas to be used more efficiently.

[0027] The rectangular welding ring can reduce the temperature, and it can also generate turbulence in the air near the smoke outlet side, realizing internal and external convection of the air here and improving the heat exchange efficiency. Attached Figure Description

[0028] The following description, in conjunction with the accompanying drawings, further illustrates this application:

[0029] Figure 1 This is a schematic diagram of a heat exchange plate for a plate air preheater and a plate air preheater according to this application;

[0030] Figure 2 This is a schematic diagram of a plate air preheater composed of multiple heat exchange plates in the prior art.

[0031] Figure 3 This is a schematic diagram of a solder joint in the prior art.

[0032] Figure descriptions: 1. Heat exchange plate; 2. Thin plate; 3. Welding ring; 31. First welding ring; 32. Second welding ring; 4. Gas flow chamber; 5. Flue gas passage. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0034] The terms "first," "second," etc. (if present) in the specification and claims of this application are used to distinguish similar objects, not to describe a specific order or sequence. Even if "second" is used before a technical feature for distinction, it does not necessarily imply the presence of "first." It should be understood that in this application, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. It should be understood that in this application, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist.

[0035] For example, X and / or Y can represent three cases: X alone, X and Y together, and Y alone. The character " / " generally indicates that the preceding and following objects are in an "OR" relationship. "Contains X, Y, and Z", "Contains X, Y, and Z" means that all three X, Y, and Z are contained; "Contains X, Y, or Z" means that one of X, Y, and Z is contained; and "Contains X, Y, and / or Z" means that any one, two, or three of X, Y, and Z are contained.

[0036] The technical solutions of this application will be described in detail below with specific embodiments. The following specific embodiments can be combined or substituted with each other according to the actual situation, and the same or similar concepts or processes may not be described again in some embodiments.

[0037] Example 1:

[0038] like Figure 1 As shown, this application provides a heat exchange plate 1 for a plate air preheater, the heat exchange plate 1 consisting of two thin plates.

[0039] 2 is formed by welding several weld rings 3 connected end to end. The unwelded parts on the two thin plates 2 are far apart to form an airflow cavity 4 for airflow. The weld rings 3 include at least a first weld ring 31 and a second weld ring 32. The first weld ring 31 and the second weld ring 32 have different shapes, or the first weld ring 31 and the second weld ring 32 have different projected areas on the heat exchange plate 1.

[0040] After adopting the above technical solution, this application has the following advantages: In the prior art, in order to adjust the heat exchange plate 1

[0041] Airflow velocity often requires replacing different fans or changing the volume of heat exchanger plate 1. This solution adjusts airflow velocity by changing the shape or projected area of ​​the welding ring 3, eliminating these complex and costly operations. Furthermore, changing heat exchange efficiency typically involves altering the plate thickness or material of heat exchanger plate 1, which can affect its strength and increase operating and maintenance costs. This solution primarily adjusts airflow velocity through different shapes or projected areas of the welding ring 3. While achieving the same heat exchange efficiency, it only requires minor structural modifications to heat exchanger plate 1, reducing its operating cost. Moreover, the welding ring 3 indirectly improves the strength of heat exchanger plate 1, allowing even larger heat exchanger plates to function properly. Since the welding ring 3 includes at least a first welding ring 31 and a second welding ring 32, and their shapes or projected areas differ, this provides multiple possibilities for adjusting airflow velocity. The airflow velocity in the airflow chamber 4 can be controlled by the combination of welding rings 3 according to the actual heat exchange requirements. Whether it is an air preheater with high heat exchange efficiency requirements or an air preheater with multiple heat exchangers and low heat exchange efficiency requirements, it can be adjusted using this heat exchange plate 1.

[0042] Furthermore, the shape formed by the welding ring 3 includes teardrop, spindle, wing, rugby ball, rectangle, spindle, or oval shapes.

[0043] Using the aforementioned technical solution, the welding points in the existing technology are often circular. This shape significantly interferes with the airflow within the airflow cavity 4, making it difficult to increase the airflow velocity within the heat exchange plate 1. Replacing them with streamlined shapes such as teardrop or spindle shapes can increase the airflow velocity within the heat exchange plate 1 without affecting its strength, thereby further improving the heat exchange efficiency. For areas where airflow velocity needs to be reduced, non-streamlined welding ring structures such as rectangles can be selected. Furthermore, the diversity of welding ring shapes allows the heat exchange plate 1 to better adapt to the needs of different industries such as power, steel, and chemical industries. Different industries have significantly different requirements for parameters such as airflow velocity and heat exchange efficiency. This heat exchange plate 1 with welding rings 3 of various shapes can meet various special industrial requirements by adjusting the shape combinations, improving the product's versatility across different industries.

[0044] Furthermore, the first solder ring 31 and the second solder ring 32 are at different angles to the airflow direction.

[0045] Using the aforementioned technical solution, the weld rings 3 at different angles can break the potential laminar flow state during airflow. In laminar flow, heat exchange between air and heat exchange plate 1 mainly relies on molecular heat conduction, which is relatively inefficient. However, by changing the angle of the weld rings 3, turbulence is generated in the air. In turbulent flow, the mixing between hot and cold fluids is more thorough, which can greatly improve the convective heat transfer coefficient, thereby enhancing the heat transfer effect. Besides adjusting the airflow velocity through the shape and projected area of ​​the weld rings 3, different angles provide a new dimension for adjusting airflow characteristics. Based on actual heat transfer requirements, the angle between the weld rings 3 and the airflow direction can be changed to precisely control the airflow velocity distribution and direction within the airflow chamber 4, achieving more flexible heat transfer efficiency adjustment.

[0046] Specifically, the angle of solder ring 3 depends on its shape. For example, a circular solder ring 3 has no angle, while for a symmetrical solder ring 3, the angle is the angle between its axis of symmetry and the horizontal line. Figure 1 As shown, the angle between the second solder ring 32 and the airflow is significantly different from the angle α2 between the first solder ring 31 and the airflow, and the tilt of the first solder ring 31 is also different.

[0047] The angled back guides the air to the inlet side. The different evaluation angles for the solder ring 3 of asymmetrical shapes are due to the different air-blocking effects of the solder ring 3, which also represent different angles.

[0048] Furthermore, the first welding ring 31 has a hollow design, while the second welding ring 32 has a solid design.

[0049] By adopting the aforementioned technical solution, the design of the first welding ring 31 reduces the overall weight of the heat exchange plate 1, while the design of the second welding ring 32 increases the thermal conductivity of the heat exchange plate 1. The cooperation between the two welding rings 3 can adapt to the needs of various working conditions and find a balance between weight and thermal conductivity.

[0050] Specifically, the hollow design of the first weld ring 31 means that the weld ends are connected to form the weld ring 3, while the middle part is not welded. The implementation design of the second weld ring 32 means that the entire area occupied by the weld ring 3 is welded.

[0051] Furthermore, adjacent first weld rings 31 are staggered along the airflow direction, and adjacent second weld rings 32 are staggered along the airflow direction.

[0052] Using the aforementioned technical solution, when the first welding ring 31 and the second welding ring 32 are arranged alternately along the airflow direction, the air will continuously encounter obstacles and change its flow direction as it flows through these welding rings 3. This frequent turning and velocity change will break the laminar flow state that the air may originally exist, and promote the formation of turbulence. In the turbulent state, the heat exchange between the air and the heat exchange plate 1 is mainly carried out through convection, and the mixing between the hot and cold fluids is more complete, which can significantly improve the convective heat transfer coefficient and thus improve the heat exchange efficiency.

[0053] Specifically, staggered arrangement refers to arrangements that are not on the same straight line.

[0054] Example 2:

[0055] Based on Embodiment 1, the number of welding rings 3 on the heat exchange plate 1 gradually increases from the air outlet to the air inlet.

[0056] Using the aforementioned technical solution, the air velocity is relatively high at the air inlet, which has a significant impact on the surface strength of the heat exchange plate 1. By arranging more welding rings 3, the airflow direction can be straightened and the surface strength of the heat exchange plate 1 can be increased. On the other hand, at the air outlet, the air velocity gradually decreases after passing through several welding rings 3. Therefore, fewer welding rings 3 are set near the air outlet to balance the requirements of air velocity and surface strength.

[0057] Example 3:

[0058] Based on Embodiment 1 or Embodiment 2, the total projected area of ​​the first welding ring 31 on the heat exchange plate 1 is greater than the total projected area of ​​the second welding ring 32 on the heat exchange plate 1. The first welding ring 31 is closer to the air inlet, and the second welding ring 32 is closer to the air outlet.

[0059] Using the aforementioned technical solution, near the air inlet, due to the large projected area of ​​the first welding ring 31, the air velocity is reduced and the distribution is more uniform. This allows the air in this area more time to exchange heat with the heat exchange plate 1. According to the principle of convective heat transfer, when the air velocity is moderate and the distribution is uniform, the convective heat transfer coefficient is relatively stable and high, enabling more effective heat transfer from the heat exchange plate.

[0060] 1. Heat is transferred to the air, while the second weld ring 32, located near the air outlet, has a small projected area and thus offers relatively less obstruction to the airflow. After undergoing the preceding series of heat exchange processes, the air needs to maintain a certain outflow velocity to avoid excessive pressure buildup at the air outlet.

[0061] Gathering ensures that air can flow smoothly out of heat exchange plate 1.

[0062] Example 4:

[0063] A plate-type air preheater includes a housing and several heat exchange plates 1 as described in any one of embodiments 1 to 3. The heat exchange plates 1 are spaced apart in the housing along the front-back direction. The area between two adjacent heat exchange plates 1 is a flue gas passage 5 for flowing flue gas. The upper side of the flue gas passage 5 is the flue gas inlet side, and the lower side is the flue gas outlet side. A plurality of first welding rings 31 in the heat exchange plates 1 form a flow guiding assembly to guide a portion of the air to the upper side of the heat exchange plates 1.

[0064] By adopting the aforementioned technical solution, a portion of the air is guided to the upper side of the heat exchange plate 1 through the flow guiding component in the heat exchange plate 1. This allows more air in the airflow chamber 4 to approach the flue gas inlet side of the flue gas channel 5, where the temperature is higher. As a result, more air achieves better heat exchange efficiency. The remaining air exchanges heat with the flue gas at the lower outlet side, where the amount of air is relatively small, thus reducing the heat exchange requirement. This improves the overall heat exchange efficiency of the heat exchange plate 1, achieving a strategy of large-scale heat exchange on the inlet side and normal heat exchange on the outlet side. This ensures that the flue gas temperature is significantly reduced and the air temperature is significantly increased, saving energy and improving production efficiency.

[0065] Furthermore, the welding ring 3 of the heat exchange plate 1 near the smoke inlet side is spindle-shaped.

[0066] Using the aforementioned technical solution, since the flue gas temperature on the inlet side is relatively high, the welding ring 3 is designed in a spindle shape, which can increase the air flow rate near the inlet side, achieve rapid heat exchange, and allow a continuous stream of cold air to quickly carry away the temperature of the flue gas.

[0067] Furthermore, the welding ring 3 near the smoke outlet side of the heat exchange plate 1 is rectangular in shape.

[0068] By adopting the aforementioned technical solution, since the flue gas temperature on the smoke outlet side is relatively low, the welding ring 3 is designed as a rectangle, which can reduce the air velocity near the smoke outlet side, increase the heat exchange time of the air at this point, improve the heat exchange capacity, and reduce the temperature of the flue gas as much as possible. In addition, the rectangular welding ring 3 can generate turbulence in the air near the smoke outlet side, realizing internal and external convection of the air at this point and improving the heat exchange efficiency.

[0069] In addition to the preferred embodiments described above, this application has other implementation methods. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection claimed in this application.

Claims

1. A heat exchange plate for a plate air preheater, characterized in that, The heat exchange plate is formed by welding two thin plates together with a number of weld rings connected end to end. The unwelded parts of the two thin plates are far apart to form an airflow cavity for airflow. The weld rings include at least a first weld ring and a second weld ring. The first weld ring and the second weld ring have different shapes and / or the projected areas of the first weld ring and the second weld ring on the heat exchange plate are different.

2. A heat exchange plate for a plate air preheater according to claim 1, characterized in that, The shape formed by the welding ring includes teardrop, spindle, wing, rugby ball, rectangle, spindle, or oval.

3. A heat exchange plate for a plate air preheater according to claim 1, characterized in that, The first and second solder rings form different angles with the airflow direction.

4. A heat exchange plate for a plate air preheater according to claim 1, characterized in that, The first welding ring has a hollow design, while the second welding ring has a solid design.

5. A heat exchange plate for a plate air preheater according to claim 1, characterized in that, Adjacent first weld rings are staggered along the airflow direction, and adjacent second weld rings are staggered along the airflow direction.

6. A heat exchange plate for a plate air preheater according to claim 1, characterized in that, The number of welding rings on the heat exchange plate gradually increases from the air outlet to the air inlet.

7. A heat exchange plate for a plate air preheater according to claim 1, characterized in that, The total projected area of ​​the first welding ring on the heat exchange plate is greater than the total projected area of ​​the second welding ring on the heat exchange plate. The first welding ring is closer to the air inlet, and the second welding ring is closer to the air outlet.

8. A plate air preheater, comprising a casing and a plurality of heat exchange plates as described in any one of claims 1 to 7, characterized in that, Several heat exchange plates are spaced apart in the casing along the front-to-back direction. The area between two adjacent heat exchange plates is a flue gas passage for the flow of flue gas. The upper side of the flue gas passage is the flue gas inlet side, and the lower side is the flue gas outlet side. Multiple first welding rings in the heat exchange plates form a flow guiding assembly to guide some air to the upper side of the heat exchange plates.

9. A plate-type air preheater according to claim 8, characterized in that, The weld ring on the heat exchange plate near the smoke inlet side is spindle-shaped.

10. A plate-type air preheater according to claim 8, characterized in that, The weld ring on the heat exchange plate near the smoke outlet side is rectangular in shape.

Images