A device and method for airflow homogenization and diameter-changing pipe of a heat exchanger in a blast furnace hot blast stove

Abstract

The present invention relates to the technical field of blast furnace hot stoves, and particularly to a variable-diameter pipe device and method for airflow homogenization of a heat exchanger in a blast furnace hot stove, which includes a round end of the variable-diameter pipe connected to a pipeline and a rectangular end of the variable-diameter pipe connected to a heat exchanger, and the round end of the variable-diameter pipe and the rectangular end of the variable-diameter pipe are connected into one body through the variable-diameter pipe; a number of vertically arranged blades are provided inside the variable-diameter pipe, and on a plane intercepted from the length direction of the rectangular end of the variable-diameter pipe towards the round end of the variable-diameter pipe, a number of the blades are arranged in a symmetric V shape, and the tip of the V shape faces the vertical diameter line of the round end of the variable-diameter pipe, and there are gaps for airflow to pass through between adjacent blades on the same side; compared with other complex flow homogenization devices, the single-row linear arrangement blade structure of the present invention effectively avoids the loss of airflow resistance, ensures smooth gas flow, and increases the degree of airflow homogenization.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace hot stoves, and particularly relates to a variable-diameter pipe device and method for air flow homogenization of a heat exchanger in a blast furnace hot stove. Background Art

[0002] Since the structural connection of a single pipe diameter cannot meet the actual needs of industrial production, a variable-diameter pipe is often introduced into the system to facilitate the connection of transition sections such as circle-rectangle and circle-circle. A variable-diameter pipe with a simple structure can meet general connection needs, but for a variable-diameter pipe connecting a regenerator or a heat exchanger, the existing simple-structured variable-diameter pipe has obvious drawbacks, mainly manifested as shortening the service life of the regenerator or the heat exchanger, affecting the heat recovery and utilization efficiency, and reducing the energy-saving effect, etc.

[0003] There is also a variable-diameter pipe structure in the blast furnace hot stove system. For example, the heat exchanger interface and the hot stove arch top have different effects due to different positions. The air and gas heat exchangers mostly adopt a circle-rectangle variable-diameter interface form, and the variable diameter causes uneven gas flow, resulting in uneven temperature distribution inside the heat exchanger. Especially for a gas heat exchanger, because the gas contains corrosive components such as chlorine ions, sulfides, and nitrides generated from iron ore smelting, the uneven temperature distribution inside the heat exchanger causes different thermal expansion degrees of the stainless steel heat exchange fins, generating a large stress concentration, and the stress corrosion effect is obvious. The greater the temperature difference inside the heat exchanger, the more obvious the influence. Seriously, the gas heat exchanger needs to be replaced after two years of use. Especially for a high-temperature heat exchanger with a pre-combustion furnace, uneven air flow will make the stress concentration more obvious.

[0004] Chinese Patent No. CN101435672B discloses a design method for an air flow homogenization and diversion device for a sudden-expansion smoke and air duct. The diversion device consists of concentric diversion vanes, which divides the flow field of the sudden-expansion smoke and air duct into independent sub-regions to achieve uniform diversion of the air flow. Although this method can effectively achieve air flow homogenization, due to the large area of the diversion vanes and the large number of diversion vanes required to achieve the uniform flow effect, considering the structural stability, the actual process installation sequence, and subsequent heat preservation, it is not easy to be applied to the actual production of hot stoves.

[0005] Chinese Utility Model Patent No. CN108800175A discloses a method and device for three-dimensional flow homogenization of a large flue. The diversion plate structure adopted by this method is more suitable for a more complex process and a continuously variable-diameter structure. At the same time, this method will cause an increase in the gas flow resistance and a significant increase in the pressure drop, which is not conducive to gas flow. For the hot stove system with a relatively large gas flow rate and a gas pressure of about 10 - 15 kPa, the increase in the flow resistance will affect the furnace burning, so this method is also not applicable.

[0006] In summary, most of the existing air flow homogenization devices are methods with complex structures or high application difficulties. Although they can achieve a certain air flow homogenization effect, for the hot blast stove system, considering the types of gas media and application environments, these methods have disadvantages such as high cost investment, insufficient stability, or difficulty in application. Summary of the Invention

[0007] The object of the present invention is to provide a variable-diameter pipe device and method for air flow homogenization of a heat exchanger in a blast furnace hot blast stove, so as to homogenize the gas flow, increase the effective heat transfer area, improve the recovery and utilization efficiency of waste heat, save energy, reduce emissions, and achieve the purpose of increasing the air temperature and extending the service life of the heat exchanger. To achieve the above object, the present invention is solved by the following technical solutions:

[0008] In the first aspect, the present invention provides a variable-diameter pipe device for air flow homogenization of a heat exchanger in a blast furnace hot blast stove, including a round end of the variable-diameter pipe connected to a pipeline and a rectangular end of the variable-diameter pipe connected to the heat exchanger, and the round end of the variable-diameter pipe and the rectangular end of the variable-diameter pipe are connected into one body through the variable-diameter pipe;

[0009] A number of vertically arranged vanes are provided in the variable-diameter pipe. On a plane intercepted from the length direction of the rectangular end of the variable-diameter pipe to the round end of the variable-diameter pipe, a number of the vanes are arranged in a symmetric V shape, and the tip of the V shape faces the vertical diameter line of the round end of the variable-diameter pipe. There is a gap for air flow between adjacent vanes on the same side.

[0010] As a further technical solution, the vanes are provided with a radian in the length direction, and the radian of the vanes increases sequentially outward with the round end of the variable-diameter pipe as the reference.

[0011] As a further technical solution, the included angle between the vanes and the rectangular end face increases sequentially outward.

[0012] As a further technical solution, the vanes are arranged between the 1 / 4 and 7 / 8 sections of the variable-diameter pipe, and there is no gas medium flow channel left between the two ends of each vane and the wall of the variable-diameter pipe.

[0013] As a further technical solution, when each of the vanes is projected onto the circular end face along the rectangular end face, two symmetrically distributed vanes are divided into a group. Starting from the group close to the circular end face, they are arranged outward in numerical order. The width Li of each vane and the gap width Li' between two different groups of adjacent vanes satisfy the relationship L1≥L2≥L3≥……≥Ln, L1'≤L2'≤L3'≤……≤Ln'.

[0014] As a further technical solution, the sum of the actual gap areas between the vanes is S, and the end face circular area of the round end of the variable-diameter pipe is Sr, and the two satisfy Sr≤S≤1.8Sr.

[0015] As a further technical solution, a connection structure is provided between adjacent blades for reinforcement.

[0016] As a further technical solution, pins are provided on the reducer pipe, and the blades are fixed to the reducer pipe through the pins. The blades and the pins are connected by fastening bolts.

[0017] As a further technical solution, multiple blades are replaced by an integral blade. Circular or rectangular holes are evenly opened on the integral blade, and the distances between the centers of the holes are equal. The opening area increases evenly from the center position of the blade geometry in the width direction and length direction of the blade. The total opening area S of the blade should be greater than or equal to the end face circle area Sr.

[0018] In a second aspect, the present invention provides an assembly method for the reducer pipe device for air flow homogenization of the blast furnace hot blast stove heat exchanger according to the first aspect, including the following steps:

[0019] After initially determining the shape of the reducer pipe and the composition of the blades according to actual application needs, a fluid dynamics simulation software is used for simulation analysis, and the design dimensions are optimized according to the analysis results. The structure composition of the air flow homogenization reducer pipe is finally determined through simulation.

[0020] Mark and cut the materials according to the design dimensions to produce the outer shell of the reducer pipe. Before welding the pins at both ends of the blade, pre-assemble the blades to ensure there is no dimensional deviation. If the reducer pipe uses external insulation, install it directly in groups in the direction from the circular end face of the reducer pipe to the rectangular end face of the reducer pipe or in the reverse order. If the reducer pipe uses internal insulation, the reserved length of the pin should be increased at this time.

[0021] Enter the reducer pipe through the circular end face of the reducer pipe, and start installing the blades in groups from the position close to the rectangular end face of the heat exchanger until the installation of the last group of blades is completed and the process ends.

[0022] The beneficial effects of the present invention are as follows:

[0023] (1) The present invention sets a single-row linear arrangement blade structure. Increasing interference can change the gas flow trajectory, enabling the air flow to be evenly divided through the blade gaps, making the air flow evenly expand outward. Compared with other complex flow equalization devices, it effectively avoids air flow resistance loss, ensures smooth gas circulation, increases the degree of air flow homogenization, and has a lower cost investment.

[0024] (2) The blades of the present invention have a curvature in the length direction, and the side with the curvature of the blade faces one end of the rectangular end of the reducer pipe. The gas flowing into the reducer pipe from the circular flue has the strongest potential energy at the center position of the circle. The curved blades enhance the distribution towards both ends of the arc while changing the outward distribution of the air flow, which is beneficial for the gas to reach the four vertex positions of the rectangular end of the reducer pipe.

[0025] (3) For each blade of the present invention, the width Li and the gap width Li' between two adjacent blades of different groups satisfy the relationships L1≥L2≥L3≥……≥Ln and L1'≤L2'≤L3'≤……≤Ln'. The wider the blade, the stronger the effect of changing the air flow direction; the larger the blade gap, the smaller the resistance to the flowing gas. The combination of the two can adjust the local distribution of the air flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute a limitation to the present invention. It should also be understood that these drawings are shown for simplicity and clarity and are not necessarily drawn to scale. The present invention will now be described and explained with additional features and details by using the accompanying drawings, in which:

[0027] Figure 1 is an axonometric view of the air flow homogenizing variable-diameter pipe device of the blast furnace hot blast stove heat exchanger in an embodiment of the present invention;

[0028] Figure 2 is a front view of the air flow homogenizing variable-diameter pipe device of the blast furnace hot blast stove heat exchanger in an embodiment of the present invention;

[0029] Figure 3 is a sectional view of the air flow homogenizing variable-diameter pipe device of the blast furnace hot blast stove heat exchanger in an embodiment of the present invention;

[0030] Figure 4 is a partially enlarged view of the blade connection end in an embodiment of the present invention;

[0031] Figure 5 is a structural diagram of a blade with a curvature in an embodiment of the present invention;

[0032] Figure 6 is a structural diagram of an integral blade when the external heat insulation method is adopted in an embodiment of the present invention;

[0033] Figure 7 is a schematic diagram of an integral blade when the external heat insulation method is adopted in an embodiment of the present invention;

[0034] Figure 8 is a fluid field air flow velocity distribution model of a rectangular end face of a common variable-diameter pipe without a flow equalizing effect, serving as a comparison diagram of the present invention;

[0035] Figure 9 is a fluid field air flow velocity distribution model of a rectangular end face after adding blades in an embodiment of the present invention.

[0036] In the figures: 1, round end of the variable-diameter pipe; 2, variable-diameter pipe; 3, blade; 4, rectangular end of the variable-diameter pipe; 5, gasket; 6, fastening bolt; 7, pin. EMBODIMENT

[0037] The technical solutions in the typical embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0038] Embodiment 1

[0039] As Figures 1 to 4 shown, this embodiment provides a variable-diameter pipe device for airflow homogenization of a heat exchanger in a blast furnace hot blast stove, including a round end 1 of the variable-diameter pipe connected to a pipeline, a rectangular end 4 of the variable-diameter pipe connected to the heat exchanger. The round end 1 of the variable-diameter pipe and the rectangular end 4 of the variable-diameter pipe are connected into one body through a variable-diameter pipe 2. A pin 7 of a blade 3 is welded on the variable-diameter pipe 2, and the blade 3 is fixed on the variable-diameter pipe 2 through the pin 7. The blade 3 and the pin 7 are connected through a fastening bolt 6 and a gasket 5 is installed in the middle. On the plane intercepted from the length direction of the rectangular end 4 of the variable-diameter pipe to the round end 1 of the variable-diameter pipe, several blades are arranged in a symmetric V shape, and the tip of the V shape faces the vertical diameter line of the round end 1 of the variable-diameter pipe. There is a gap for the airflow to pass through between adjacent blades 3 on the same side.

[0040] This embodiment sets a single-row linear arrangement of blade structures. Increasing interference can change the gas flow trajectory, enabling the airflow to be evenly divided through the blade gaps, making the airflow evenly expand outwards. Compared with other complex flow-uniforming devices, it effectively avoids airflow resistance loss, ensures smooth gas flow, and has a lower cost investment while increasing the degree of airflow homogenization.

[0041] In this embodiment, the blades 3 are vertically arranged and symmetrically distributed along the vertical plane of the center line between the 1 / 4 to 7 / 8 pipe sections on the variable-diameter pipe 2 and are staggered by a set distance.

[0042] The diameter of the round end 1 of the variable-diameter pipe is 3000 mm, the length L of the rectangular end 4 of the variable-diameter pipe is 6000 mm, the width is 3200 mm, the number of groups n of the blades 3 is 5, and the distance between the round end 1 of the variable-diameter pipe and the rectangular end 4 of the variable-diameter pipe is 2000 mm. There is no gas medium flow channel left between the two ends of the blade 3 and the variable-diameter pipe 2, and the connection line between the pins 7 at both ends of the blade 3 is the bisector of the weight of the blade 3. The distance between the pins 7 of adjacent two blades is equal. When the blade 3 projects from the rectangular end 4 of the variable-diameter pipe to the round end 1 of the variable-diameter pipe, two symmetrically distributed blades are divided into a group. Starting from the group closest to the round end face, they are respectively denoted as A1, A2... A5. The fixing pins of the blades A1 to A5 on the same side are on the same straight line.

[0043] The actual gap area between the blades A1 and A1 is S1, the actual gap area between the adjacent blades A1 and A2 is S2, the actual gap area between the adjacent blades A2 and A3 is S3... The actual gap area between the blade A5 and the variable-diameter pipe 2 is S6.

[0044] The sum of the actual void areas between the blades is \(S = \text{SUM}(S1 + 2S2+\cdots+ 2S6)\). The end face circular area of the variable-diameter pipe circular end 1 is \(Sr\). The sum of the actual void areas between the blades is \(S\), and the end face circular area of the variable-diameter pipe circular end is \(Sr\). The two satisfy \(Sr\leq S\leq1.8Sr\). In this embodiment, the sum of the actual void areas between the blades \(S\) is initially selected as \(S = 1.3Sr\). When the area is relatively large, gas molecules have enough space to pass through the blade positions in the middle and do not need to bypass the far boundary area and then pass through the blades; when the area is relatively small, the flow resistance is increased, which is not conducive to the normal operation of the hot blast stove.

[0045] In the initial design, the width \(Li\) of each blade and the void width \(Li'\) between two adjacent blades of different groups satisfy the relationship \(L1\geq L2\geq L3\geq\cdots\geq Ln\), \(L1'\leq L2'\leq L3'\leq\cdots\leq Ln'\). The wider the blade, the stronger the effect of changing the gas flow direction, but the total cross-sectional area is limited and it should not be too wide; the larger the blade gap, the smaller the resistance to the flowing gas. The two combined can adjust the local distribution of the gas flow.

[0046] As Figure 9 shown, it is the air flow velocity distribution model of the end face fluid field of the variable-diameter pipe rectangular end 4 after adding blade 3 ( Figure 8 is the air flow velocity distribution model of the ordinary variable-diameter pipe rectangular end face fluid field without the flow equalizing effect, which is used as the control diagram of the present invention). It should be noted that this fluid model is only for more intuitively understanding the flow equalizing effect of the present invention and is not the optimal solution under this model. The model can be further optimized by adjusting the position and width of blade 3 and the distance between blade 3s. At the same time, increasing the number of blade 3s can make the flow equalizing effect more obvious.

[0047] In practical applications, for the heat exchanger connected to the rectangular end face interface, the heat exchanger is composed of heat exchange fins evenly distributed in a linear arrangement and the heat exchange fins have a certain thickness. Before the air flow enters the heat exchanger, it will be redistributed in a local area. It can be seen from the model that this embodiment can significantly homogenize the total air flow volume in the local area.

[0048] Embodiment 2

[0049] This embodiment provides a variable-diameter pipe device for air flow homogenization of a blast furnace hot blast stove heat exchanger, which is different from Embodiment 1 in that:

[0050] As Figure 5 shown, the length direction of blade 3 has a radian, and the radius of the arc where blade 3 is located is \(R\) a， then it satisfies \(r < R\) a1 <R a2 <R a3 <……<R anThe effect of uniformizing the air flow is more obvious at this time, and the side of the blade 3 with a curvature faces one end of the rectangular end of the reducer pipe. The potential energy of the gas flowing from the circular flue into the reducer pipe is the strongest at the center of the circle. The blade with a curvature enhances the distribution towards both ends of the arc while changing the outward distribution of the air flow, which is beneficial for the gas to reach the four vertices of the rectangular end of the reducer pipe. However, considering the actual production conditions, the radius of the blade curvature is selected as a constant value so that R a1 = R a2 = R a3 =……= R an = X is more convenient for manufacturing; the technical solution of this embodiment is applicable when the difference between the end face diameter of the circular end 1 of the reducer pipe and the width of the rectangular end 4 of the reducer pipe is relatively large.

[0051] The blade 3 is horizontally arranged, and the blade 3 is symmetrically distributed with respect to the horizontal plane passing through the center line of the reducer pipe 2. The blades 3 are connected and reinforced. The simplest way is to add a connecting rod at the middle position in the length direction of the blade; the materials of the blade, pin, cushion block, and bolt are selected according to the application environment, and can be low alloy steel, stainless steel, or other types of materials;

[0052] The included angle between the blade and the rectangular end face is α, and the optional α1 ≤ α2 ≤ α3 ≤ …… ≤ α n , and the effect of changing the air flow direction is stronger as the angle increases, which can improve the flow splitting effect.

[0053] Embodiment Three

[0054] This embodiment provides a device for uniformizing the air flow of a hot blast stove heat exchanger in a blast furnace, which is different from Embodiment One in that:

[0055] As shown in Figure 6 , Figure 7 , in this embodiment, the reducer pipe 2 is heat-insulated by an external heat-insulation method. Then, multiple blades can be optionally replaced by one piece. The integral blade is uniformly provided with circular or rectangular holes, and the distances between the centers of the holes are equal. The opening areas uniformly increase in two directions, namely, the width direction A and the length direction B, from the center position of the geometric body of the blade 3. The total opening area S of the blade 3 should be ≥ the end face circle area Sr. The ratio of the minimum circle diameter to the maximum circle diameter on the blade 3 can be determined by referring to the ratio of the end face diameter of the circular end 1 of the reducer pipe to the length of the rectangular diagonal of the rectangular end 4 of the reducer pipe.

[0056] The integral blade is applicable to the form of external heat insulation at the variable diameter position. The heat insulation should be carried out after the installation of the reducer pipe. The heat insulation methods include internal heat insulation and external heat insulation. The rectangular end of the reducer pipe is connected to the equipment and is completely sealed and cannot be accessed. The pipe connected to the circular end of the reducer pipe can be accessed. However, a closed space is formed between the integral blade and the rectangular end of the reducer pipe, which hinders the internal heat insulation construction. However, the integral blade has high stability and is convenient for installation.

[0057] Embodiment Four

[0058] This embodiment provides an installation method for a variable-diameter pipe device for air flow homogenization in a blast furnace hot blast stove heat exchanger, including the following steps:

[0059] (1) After initially determining the shape of the variable-diameter pipe and the composition of the vanes according to the design conditions, use fluid mechanics simulation software for simulation analysis, and repeatedly optimize the design dimensions according to the analysis results to ensure sufficient air flow homogenization, and finally determine the structural composition of the air flow homogenization variable-diameter pipe.

[0060] (2) Fabrication of the variable-diameter pipe and vanes: Mark and cut the materials according to the design dimensions. First, assemble and weld the plates to fabricate the outer shell of the variable-diameter pipe 2. Determine the installation positions of the pins 7 according to the arrangement of the vanes 3. Adjust the angles of the pins 7 and weld them to the outer shell of the variable-diameter pipe 2. Before welding all the pins 7 at both ends of the vane 3, pre-assemble the vane 3 to ensure there is no dimensional deviation.

[0061] (3) Installation of the outer insulation vanes: If the outer insulation is adopted at the position of the variable-diameter pipe, the vane 3 can be directly installed and connected to the pin 7 at this time, and the installation is carried out group by group in the direction from the round end 1 of the variable-diameter pipe to the rectangular end 4 of the variable-diameter pipe or in the reverse order, and the vanes are fixed by pressing gaskets 5 and fastening bolts 6; if the inner insulation is adopted at the position of the variable-diameter pipe, the length of the pin 7 should be increased at this time to reserve the construction thickness of the spraying layer, and the connecting end of the pin 7 and the vane 3 needs to be protected by sleeving or tying cloth strips to ensure that the spraying construction will not block the bolt holes, and it will not affect the subsequent construction and is convenient for demolition. In addition, anchor nails are welded on the inner wall of the variable-diameter pipe 2, and the installation of the vane 3 is carried out after the spraying is completed.

[0062] (4) Installation of the variable-diameter pipe: Connect the variable-diameter pipe 2 to the pipeline and the heat exchanger, and carry out heat preservation treatment after welding firmly. The process of the outer insulation ends after the heat preservation is completed, while for the inner insulation, the sleeves or tying cloth strips for protecting the connecting ends of the pins 7 need to be removed.

[0063] (5) Installation of the inner insulation vanes: Enter the variable-diameter pipe 2 through the round end 1 of the variable-diameter pipe, and start installing the vanes 3 group by group from the position close to the rectangular end 4 of the variable-diameter pipe until the installation of the last group of vanes A1 is completed and the process ends.

[0064] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and decorations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention all belong to the protection scope of the technical solution of the present invention.

Claims

1. A variable-diameter pipe device for airflow homogenization of a heat exchanger in a blast furnace hot blast stove, characterized in that It includes a round end of a reducer pipe connected to a pipeline and a rectangular end of the reducer pipe connected to a heat exchanger. The round end of the reducer pipe and the rectangular end of the reducer pipe are connected into one body through the reducer pipe. A number of vertically arranged blades are provided inside the reducer pipe. On a plane intercepted from the length direction of the rectangular end of the reducer pipe towards the round end of the reducer pipe, several of the blades are arranged in a symmetric V shape, and the tip of the V shape faces the vertical diameter line of the round end of the reducer pipe. There are gaps for air flow between adjacent blades on the same side. The blades are arranged in a single-row linear arrangement blade structure. The blades are provided with arcs in the length direction, and the arcs of the blades gradually increase outward with the round end of the reducer pipe as the reference. The side of the blade with the arc faces one end of the rectangular end of the reducer pipe. The angles between the blades and the rectangular end face gradually increase outward. When each of the blades is projected along the rectangular end face towards the round end face, two symmetrically distributed blades are divided into a group. Starting from the group closest to the round end face, they are arranged outward in numerical order. The width Li of each of the blades and the gap width Li' between two different groups of adjacent blades satisfy the relationship L1≥L2≥L3≥……≥Ln, L1'≤L2'≤L3'≤……≤Ln'.

2. The variable-diameter pipe device for airflow homogenization of a heat exchanger in a blast furnace hot blast stove according to claim 1, characterized in that The sum of the actual gap areas between each of the blades is S, and the end face circle area of the round end of the reducer pipe is Sr. The two satisfy Sr≤S≤1.8Sr.

3. The variable-diameter pipe device for airflow homogenization of a heat exchanger in a blast furnace hot blast stove according to claim 1, characterized in that Adjacent blades are reinforced by setting connection structures.

4. The variable-diameter pipe device for airflow homogenization of a heat exchanger in a blast furnace hot blast stove according to claim 1, characterized in that Pins are provided on the reducer pipe, and the blades are fixed to the reducer pipe through the pins. The blades and the pins are connected through fastening bolts.

5. An assembly method of the variable-diameter pipe device for airflow homogenization of a heat exchanger in a blast furnace hot blast stove according to any one of claims 1-4, characterized in that It includes the following steps: After the reducer pipe device preliminarily determines the shape of the reducer pipe and the blade composition according to actual application needs, it uses fluid mechanics simulation software for simulation analysis, and optimizes the design dimensions according to the analysis results. Through simulation, the structural composition of the air flow homogenization reducer pipe is finally determined. Mark and cut the materials according to the design dimensions to make the outer shell of the reducer pipe. Before welding the pins at both ends of the blades, pre-assemble the blades to ensure there are no dimensional deviations. If the reducer pipe uses external thermal insulation, it is directly installed group by group in the direction from the round end face of the reducer pipe towards the rectangular end face of the reducer pipe or in the reverse order. If the reducer pipe uses internal thermal insulation, the pins should increase the reserved length at this time. Enter the reducer pipe through the round end face of the reducer pipe, and install the blades group by group starting from the position close to the rectangular end face of the heat exchanger until the installation of the last group of blades is completed and the process ends.

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