A plate heat exchanger

Abstract

The present invention discloses a plate heat exchanger. The plate heat exchanger comprises a shell and a core, wherein the core is arranged inside the shell, and the core comprises a plurality of modules and a plurality of comb plates, wherein the plurality of modules are fluidically connected, the comb plates are connected to the corners of the modules by welding, and the plurality of modules are welded together by the comb plates. The plate heat exchanger according to the present invention adopts a modular design, has a small size, a light weight, a large heat exchange area, a high heat exchange efficiency, can meet the use of large load conditions, is resistant to high temperature and high pressure, and is easy to clean and maintain.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, and in particular to a plate heat exchanger. Background Art

[0002] The heat exchangers in existing petrochemical plants are usually shell and tube heat exchangers. As the demand for large-scale single units increases, the demand for heat exchange area is also increasing, but the processing difficulty and manufacturing quality of large shell and tube heat exchangers are difficult to guarantee. In recent years, plate heat exchangers have been widely used in the industrial field due to their advantages such as good temperature and pressure resistance, high heat transfer efficiency, small footprint and light weight, and have successfully replaced shell and tube heat exchangers in many occasions.

[0003] The core of the plate heat exchanger includes multiple plates, but because the plates are compressed and formed by a press at one time, the plates are limited by the press table and the pressure load, resulting in a small maximum area of ​​the plates. As a result, the heat exchange area of ​​a single plate heat exchanger is small and cannot meet the use of high-load conditions.

[0004] Therefore, a plate heat exchanger is needed to at least partially solve the problems existing in the prior art. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In order to at least partially solve the above problem, according to a first aspect of the present invention, a plate heat exchanger is provided, the plate heat exchanger comprising:

[0007] case;

[0008] A core body, the core body is arranged inside the shell, and the core body comprises:

[0009] a plurality of modules, the plurality of modules being in fluid communication with each other; and

[0010] A plurality of comb plates, wherein the comb plates are connected to the corners of the modules by welding, and the plurality of modules are welded together by the comb plates.

[0011] The plate heat exchanger according to the present invention adopts a modular design, has a small size, light weight, a large heat exchange area, and a high heat exchange efficiency, can meet the use of large load conditions, is resistant to high temperature and high pressure, and is easy to clean and maintain.

[0012] Optionally, the plurality of modules include a first module and a second module adjacent to each other along a first direction, and the first fluid can flow between the first module and the second module along the first direction. In this way, a larger heat exchange area can be achieved.

[0013] Optionally, the plurality of modules include a third module and a fourth module spaced apart along the second direction, and the second fluid flows between the third module and the fourth module along the second direction. In this way, a larger heat exchange area can be achieved.

[0014] Optionally, there is a cavity between the third module and the fourth module, and the second fluid flows into the fourth module through the cavity. In this way, it can meet the use of large load conditions.

[0015] Optionally, the module includes a plurality of heat exchange plates arranged in parallel, and adjacent heat exchange plates are connected together by welding. In this way, the core of the plate heat exchanger has a smaller volume, a larger heat exchange area, and no gasket is provided between the heat exchange plates, and can be applied in high temperature and high pressure environments.

[0016] Optionally, the heat exchange plate includes a main body and a U-shaped protrusion protruding along the thickness direction of the main body, the U-shaped protrusion is arranged at the end of the main body, the U-shaped protrusion includes two opposite side protrusions and an end protrusion located between the two side protrusions, and the comb plate is welded to the side protrusions. In this way, the heat exchange plate is prevented from being deformed by welding.

[0017] Optionally, two adjacent heat exchange plates are arranged so that the protruding directions of their respective U-shaped protrusions are opposite, so that the respective U-shaped protrusions of the two adjacent heat exchange plates are welded together to form a first fluid channel between the two heat exchange plates, thereby facilitating the formation of a fluid channel.

[0018] Optionally, two adjacent heat exchange plates are configured such that the protruding directions of their respective U-shaped protrusions are opposite, so that the respective main bodies of the two adjacent heat exchange plates are welded together to form a second fluid channel between the two heat exchange plates, thereby preventing the two fluids from mixing.

[0019] Optionally, the main body is provided with corrugations, the corrugations protrude from the main body in the same direction as the U-shaped protrusions, and the corrugations of adjacent heat exchange plates are arranged in a staggered manner, thereby increasing the heat exchange area between fluids, forming a three-dimensional mesh fluid channel, and improving heat exchange efficiency.

[0020] Optionally, it also includes:

[0021] A column frame, the column frame is arranged at a corner of the core body and extends along the height direction of the shell, and the column frame is connected to the comb plate by welding; and

[0022] A column is arranged inside the column frame and is detachably connected to the shell.

[0023] In this way, disassembly and assembly are facilitated and deformation of the heat exchange plate is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following drawings of the present invention are used as part of the present invention for understanding the present invention. The drawings show embodiments of the present invention and their descriptions, and are used to explain the device and principle of the present invention. In the drawings,

[0025] Figure 1 A three-dimensional diagram of a plate heat exchanger according to a preferred embodiment of the present invention;

[0026] Figure 2 for Figure 1 A three-dimensional view of a heat exchange plate of a plate heat exchanger shown;

[0027] Figure 3 For multiple Figure 2 A schematic diagram of the structure in which the heat exchange plates are connected together;

[0028] Figure 4 for Figure 1 A perspective view of a module of a plate heat exchanger is shown;

[0029] Figure 5 for Figure 1 A perspective view of the core of the plate heat exchanger shown;

[0030] Figure 6 for Figure 5 A schematic diagram showing the connection between the core and the top plate; and

[0031] Figure 7 for Figure 5 Schematic diagram of the connection between the core and the column shown.

[0032] Description of reference numerals:

[0033] 100: Plate heat exchanger 110: Shell

[0034] 111: First panel 112: Second panel

[0035] 113: First feed port 114: Second feed port

[0036] 116: Top plate 120: Core

[0037] 131: First module 132: Second module

[0038] 133: Module 3 134: Module 4

[0039] 140: Comb plate 150: Heat exchange plate

[0040] 151: Main body 152: U-shaped protrusion

[0041] 154: first heat exchange plate 155: second heat exchange plate

[0042] 156: third heat exchange plate 157: fourth heat exchange plate

[0043] 158: Side protrusion 159: End protrusion

[0044] 160: Column 161: Column frame DETAILED DESCRIPTION

[0045] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0046] In order to fully understand the present invention, a detailed structure will be presented in the following description to illustrate the present invention. Obviously, the implementation of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments and should not be construed as being limited to the embodiments presented here.

[0047] It should be understood that the purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention, and the singular forms "a", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. When the terms "comprise" and / or "include" are used in this specification, they indicate the presence of the features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof. The terms "upper", "lower", "front", "back", "left", "right" and similar expressions used in the present invention are for illustrative purposes only and are not limiting.

[0048] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifications and do not have any other meanings, such as a specific order, etc. Moreover, for example, the term "first component" itself does not imply the existence of the "second component", and the term "second component" itself does not imply the existence of the "first component".

[0049] Hereinafter, specific embodiments of the present invention will be described in more detail with reference to the accompanying drawings, which illustrate representative embodiments of the present invention and do not limit the present invention.

[0050] The present invention provides a plate heat exchanger 100, such as Figure 1 and Figure 5 As shown, the plate heat exchanger 100 includes a shell 110 and a core 120 (the core 120 is Figure 5 As shown in FIG. 1 , the core 120 is disposed inside the housing 110. The housing 110 includes a panel. To facilitate the flow of fluid into the core 120, the panel is provided with an opening for the fluid to flow in or out. Figure 1 As shown, the panel may include a first panel 111, a second panel 112, a third panel and a fourth panel. The first panel 111 and the third panel may be arranged opposite to each other, and the second panel 112 and the fourth panel may be arranged opposite to each other.

[0051] exist Figure 1 In the illustrated embodiment, the first panel 111 may be provided with a first feed port 113, which is in fluid communication with the core 120 and is used to deliver the first fluid into the core 120. The third panel may be provided with a first discharge port (not shown), which is in fluid communication with the core 120 and is used to discharge the first fluid after heat exchange.

[0052] The second panel 112 may be provided with a second feed port 114, which is in fluid communication with the core 120 and is used to deliver the second fluid into the core 120. The fourth panel may be provided with a second discharge port (not shown), which is in fluid communication with the core 120 and is used to discharge the second fluid after heat exchange.

[0053] In the core 120 , the first fluid and the second fluid flow in different directions (eg, directions perpendicular to each other), respectively, and the first fluid and the second fluid can perform heat exchange in the core 120 .

[0054] The specific structure of the core 120 is described below.

[0055] In order to increase the overall heat exchange area inside the plate heat exchanger 100, Figure 5 In the illustrated embodiment, the core 120 includes a plurality of modules and a plurality of comb plates 140, the plurality of modules are fluidically connected, the comb plates 140 are connected to the corners of the modules by welding, and the plurality of modules are welded together by the comb plates 140. In this way, the plate heat exchanger 100 can be made of less raw materials, and the plate heat exchanger 100 can achieve heat recovery to the maximum extent, consume less energy, have a smaller temperature difference at the end, and can better handle the problem of temperature crossover.

[0056] For example, Figure 5 As shown, the plurality of modules include a first module 131, a second module 132, a third module 133 and a fourth module 134, and the first module 131, the second module 132, the third module 133 and the fourth module 134 are respectively connected to the comb plate 140 by welding. Of course, the number and arrangement of the modules are not limited to the number and arrangement listed in this embodiment. For example, the plurality of modules include at least two modules, and the at least two modules can be arranged in an array.

[0057] In order to increase the heat exchange area inside the plate heat exchanger 100, the first module 131 and the second module 132 can be attached to each other along the first direction D1 and welded together through the attached comb plates 140, and the first fluid can flow between the first module 131 and the second module 132 along the first direction D1. The third module 133 and the fourth module 134 can be attached to each other along the first direction D1 and welded together through the attached comb plates 140, and the first fluid can flow between the third module 133 and the fourth module 134 along the first direction D1.

[0058] The first module 131 and the third module 133 may be spaced apart along the second direction D2 and welded together through the opposite comb plates 140, and the second fluid flows along the second direction D2 between the first module 131 and the third module 133. The second module 132 and the fourth module 134 may be spaced apart along the second direction D2 and welded together through the opposite comb plates 140, and the second fluid flows along the second direction D2 between the second module 132 and the fourth module 134.

[0059] In an optional embodiment, there is a cavity between the first module 131 and the third module 133, and the second fluid flows along the second direction D2 through the cavity between the first module 131 and the third module 133 to the third module 133. The flow mode of the second fluid along the second direction D2 between the second module 132 and the fourth module 134 is similar to the flow mode between the first module 131 and the third module 133, and will not be repeated here.

[0060] The structure of the first module 131 is explained below by taking it as an example.

[0061] like Figures 2 to 4As shown, the first module 131 may include a plurality of heat exchange plates 150, which are arranged in parallel and adjacent heat exchange plates 150 are connected together by welding. In this way, the volume of the core 120 of the plate heat exchanger 100 can be made smaller, the difficulty of processing can be reduced during the production process, torsional deformation can be avoided, the manufacturing accuracy can be guaranteed, and the cost is low. At the same time, the heat exchange area of ​​the core 120 can be made larger, and no gasket is set between the heat exchange plates 150, which can be used in high temperature and high pressure environments. Less scale can also be formed inside the plate heat exchanger 100, reducing the number of cleaning times and extending the service life of the plate heat exchanger 100.

[0062] The cross section of the heat exchange plate 150 may be rectangular for easy connection and arrangement. In order to make the connection between adjacent heat exchange plates 150 more secure, preferably, the heat exchange plates 150 may be connected together by automatic plasma beam welding.

[0063] In order to facilitate the fluid to flow between two adjacent heat exchange plates 150, Figure 2 and Figure 3 As shown, preferably, the heat exchange plate 150 includes a body portion 151 and a U-shaped protrusion 152, and the U-shaped protrusion 152 can protrude along the thickness direction of the body portion 151. The U-shaped protrusion 152 is arranged at the end of the body portion 151, and the U-shaped protrusion 152 includes two opposite side protrusions 158 and an end protrusion 159 located between the two side protrusions 158, and the comb plate 140 is welded to the side protrusions 158.

[0064] For example, Figure 3 As shown, the plurality of heat exchange plates may include a first heat exchange plate 154, a second heat exchange plate 155, a third heat exchange plate 156 and a fourth heat exchange plate 157 arranged in parallel. The first heat exchange plate 154 and the second heat exchange plate 155 are adjacent to each other, and the first heat exchange plate 154 and the second heat exchange plate 155 are configured so that the protruding directions of their respective U-shaped protrusions 152 are opposite. The body portion 151 of the first heat exchange plate 154 and the body portion 151 of the second heat exchange plate 155 are connected together by welding, so that a second fluid channel can be formed between the first heat exchange plate 154 and the second heat exchange plate 155, and the second fluid can flow through the second fluid channel.

[0065] The second heat exchange plate 155 is adjacent to the third heat exchange plate 156, and the second heat exchange plate 155 and the third heat exchange plate 156 are configured so that their respective U-shaped protrusions protrude in opposite directions, and the U-shaped protrusion of the second heat exchange plate 155 and the U-shaped protrusion of the third heat exchange plate 156 are connected together by welding, so that a first fluid channel is formed between the second heat exchange plate 155 and the third heat exchange plate 156, and the first fluid can flow through the first fluid channel.

[0066] The third heat exchange plate 156 is adjacent to the fourth heat exchange plate 157, and the third heat exchange plate 156 and the fourth heat exchange plate 157 are configured so that their respective U-shaped protrusions protrude in opposite directions, and the main body of the third heat exchange plate 156 and the main body of the fourth heat exchange plate 157 are connected together by welding to form a second fluid channel, and the second fluid can flow through the second fluid channel.

[0067] In order to further increase the heat exchange area between fluids, such as Figure 2 As shown, the main body 151 of the heat exchange plate 150 may be provided with corrugations, which protrude from the main body 151 in the same direction as the U-shaped protrusion 152, so that the flow turbulence of the fluid can be high, and the heat transfer coefficient can reach 2 to 4 times that of a conventional shell and tube heat exchanger, so that the heat exchange area of ​​the plate heat exchanger 100 is 25% to 50% of that of a conventional shell and tube heat exchanger. Preferably, the depth of the corrugations can be 2 mm to 10 mm, so that the heat exchange efficiency can be further improved. Furthermore, in order to improve the heat exchange efficiency of the first fluid and the second fluid in the module, the corrugations of adjacent heat exchange plates 150 can be arranged in a staggered manner to form a three-dimensional mesh fluid channel, and the first fluid and the second fluid can flow in a cross-staggered partition wall manner in the module.

[0068] The comb plate 140 can be welded to the side protrusions 158 of the heat exchange plate 150, so as to prevent the heat exchange plate 150 from being deformed by welding. Preferably, in order to make the comb plate 140 and the heat exchange plate 150 connected more firmly and stably, the four corners of the heat exchange plate 150 are provided with side protrusions 158, and each side protrusion 158 can be connected to the comb plate 140.

[0069] Further, in order to prevent the first fluid and the second fluid from mixing, as Figure 4 As shown, the four corners of the first module 131 can be connected to a comb plate 140. Preferably, the same corner of the first module 131 can be connected to multiple comb plates 140, and the multiple comb plates 140 can be arranged in sequence along the height direction of the first module 131. Adjacent comb plates 140 can be connected together by welding, so that it is easy to process the comb plates 140, reduce errors, and reduce deformation during welding. Of course, in order to facilitate processing, the same corner of the first module 131 can be connected to the same comb plate 140.

[0070] In order to make the heat exchange plate 150 and the comb plate 140 welded more firmly, the heat exchange plate 150 and the comb plate 140 can be connected together by automatic plasma beam welding. In order to enhance the structural strength of the heat exchange plate 150 and the comb plate 140, preferably, the thickness of the heat exchange plate 150 can be 0.8mm to 1.2mm, and the thickness of the comb plate 140 can be 2mm to 5mm. In addition, in order to further improve the heat exchange efficiency and facilitate processing, the material of the heat exchange plate 150 and / or the comb plate 140 can be austenitic stainless steel, nickel-based alloy or titanium.

[0071] Furthermore, if Figure 5 and Figure 7 As shown, in order to make the core 120 and the panel connected together with good sealing, the plate heat exchanger also includes a column 160 and a column frame 161. The column frame 161 is arranged at the corner of the core 120 and extends along the height direction of the shell 110. The comb plate 140 can be connected to the column frame 161 by welding. The corners of the first module 131, the second module 132, the third module 133 and the fourth module 134 can be welded with the column frame 161 respectively. Preferably, in order to ensure that the column frame 161 has sufficient structural strength, the material of the column frame 161 can be austenitic stainless steel, nickel-based alloy or titanium, and the thickness of the column frame 161 can be 2mm to 5mm.

[0072] The column 160 is disposed inside the column frame 161 and is detachably connected to the housing 110. Preferably, the column 160 can be detachably connected to the panel by bolts, so as to facilitate disassembly and assembly, and then facilitate cleaning and maintenance of the core 120. In order to ensure sufficient structural strength, the column 160 is made of carbon steel. The column frame 161 and the column 160 can separate the first fluid and the second fluid to prevent the first fluid from the first feed port 113 and the second fluid from the second feed port 114 from mixing.

[0073] Furthermore, if Figure 6 As shown, the shell 110 may also include a top plate 116. In an optional embodiment, a top plate 116 may be provided on the top of each module to maintain pressure. For example, the top plate 116 may be connected to the corner of the topmost heat exchange plate of the first module 131 and the comb plate 140 connected to the first module 131 by welding. In order to ensure the sealing effect of the plate heat exchanger 100 and the stability of its structure, multiple top plates 116 may be connected together by welding. In another optional embodiment, for ease of operation, the tops of multiple modules may be connected to the same top plate 116.

[0074] Furthermore, the housing 110 may further include a bottom plate (not shown), and the connection between the bottom plate and the column 160 is similar to the connection between the top plate 116 and the column 160, which will not be described in detail. Preferably, in order to ensure the structural strength of the top plate 116 and the bottom plate, the thickness of the top plate 116 and / or the bottom plate is 2 to 5 mm.

[0075] The working process of the plate heat exchanger 100 is described below.

[0076] The first feed port 113 is in fluid communication with the core 120, and the first fluid can enter the first module 131 and the third module 133 through the first feed port 113. The second feed port 114 is in fluid communication with the core 120, and the second fluid can enter the first module 131 and the second module 132 through the second feed port 114.

[0077] The first fluid may flow along the first direction D1 from the first module 131 to the second module 132, and may flow along the first direction D1 from the third module 133 to the fourth module 134. The second fluid may flow along the second direction D2 from the first module 131 to the third module 133, and may flow along the second direction D2 from the second module 132 to the fourth module 134.

[0078] The first fluid and the second fluid can perform heat exchange in the core 120 , the first outlet can discharge the first fluid after the heat exchange, and the second outlet can discharge the second fluid after the heat exchange.

[0079] In another embodiment not shown in the figure, a feed port and a discharge port may be arranged on the same panel. For example, a first panel and a second panel are adjacent, and the first panel is arranged with a first feed port and a first discharge port, and the first feed port may be arranged above the first discharge port along the height direction of the plate heat exchanger, and the first fluid may enter the core through the first feed port. A second panel is arranged with a second feed port and a second discharge port, and the second feed port may be arranged above the second discharge port along the height direction of the plate heat exchanger, and the second fluid may enter the core through the second feed port.

[0080] The core may be provided with a baffle, and the first fluid and the second fluid may flow back and forth in the core and perform heat exchange. The first discharge port may discharge the first fluid after heat exchange, and the second discharge port may discharge the second fluid after heat exchange.

[0081] According to the plate heat exchanger of the present invention, the plate heat exchanger includes a shell and a core, the core is arranged inside the shell, the core includes multiple modules and multiple comb plates, the multiple modules are fluidically connected, the comb plates are connected to the corners of the modules by welding, and the multiple modules are welded together by the comb plates. In this way, the plate heat exchanger of the present invention has a small volume, light weight, large heat exchange area, high heat exchange efficiency, meets the use of high load conditions, and is resistant to high temperature and high pressure, and is easy to clean and maintain. In addition, the plate heat exchanger of the present invention adopts a modular design, which is easy to disassemble and assemble, and the damaged or fouled modules can be repaired or replaced separately.

[0082] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field of the present invention. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present invention. Terms such as "parts" and "pieces" appearing in this article may represent either a single part or a combination of multiple parts. Terms such as "installation" and "setting" appearing in this article may represent either a component being directly attached to another component or a component being attached to another component through an intermediate. Features described in this article in one embodiment may be applied to another embodiment alone or in combination with other features, unless the feature is not applicable in the other embodiment or otherwise specified.

[0083] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A plate heat exchanger, characterized in that: The plate heat exchanger comprises: case; A core body, the core body is arranged inside the shell, and the core body comprises: a plurality of modules, the plurality of modules being in fluid communication with each other; and A plurality of comb plates, wherein the comb plates are connected to the corners of the modules by welding, and the plurality of modules are welded together by the comb plates. Wherein, the multiple modules include a first module and a second module attached to each other along a first direction, the first module and the second module are welded together through the attached comb plates, and a first fluid can flow between the first module and the second module along the first direction; the multiple modules include a first module and a third module spaced apart along a second direction, the first module and the third module are welded together through the relative comb plates, and a second fluid flows between the first module and the third module along the second direction.

2. The plate heat exchanger according to claim 1, characterized in that: A cavity is defined between the first module and the third module, and the second fluid flows into the third module through the cavity.

3. The plate heat exchanger according to claim 1, characterized in that: The module comprises a plurality of heat exchange plates arranged in parallel, and adjacent heat exchange plates are connected together by welding.

4. The plate heat exchanger according to claim 3, characterized in that: The heat exchange plate includes a main body and a U-shaped protrusion protruding along the thickness direction of the main body, the U-shaped protrusion is arranged at the end of the main body, the U-shaped protrusion includes two opposite side protrusions and an end protrusion located between the two side protrusions, and the comb plate is welded to the side protrusions.

5. The plate heat exchanger according to claim 4, characterized in that: The two adjacent heat exchange plates are arranged such that the protruding directions of their respective U-shaped protrusions are opposite, so that the respective U-shaped protrusions of the two adjacent heat exchange plates are welded together to form a first fluid channel between the two heat exchange plates.

6. The plate heat exchanger according to claim 4, characterized in that: The two adjacent heat exchange plates are arranged such that the protruding directions of the respective U-shaped protrusions are opposite, so that the respective body parts of the two adjacent heat exchange plates are welded together to form a second fluid channel between the two heat exchange plates.

7. The plate heat exchanger according to claim 4, characterized in that: The main body is provided with corrugations, the corrugations protrude from the main body in the same direction as the U-shaped protrusions, and the corrugations of adjacent heat exchange plates are arranged in a staggered manner.

8. The plate heat exchanger according to claim 1, characterized in that: Also includes: A column frame, the column frame is arranged at a corner of the core body and extends along the height direction of the shell, and the column frame is connected to the comb plate by welding; and A column is arranged inside the column frame and is detachably connected to the shell.

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