Original surface type heat exchanger core body welding structure and welding process

Abstract

The invention discloses an original surface type heat exchanger core body welding structure and a welding process, and relates to the technical field of energy power, the original surface type heat exchanger core body welding structure comprises heat exchange fins, plane areas are reserved around the heat exchange fins, and smoke unit edge strips and air circulation unit edge strips are placed on the plane areas; according to the scheme, the diffusion welding technology is adopted, all welding interfaces are formed at a time, compared with an existing product adopting argon arc welding or laser welding, the risk caused by uncertain factors in the welding process is reduced, the welding efficiency is improved, and the production cost is reduced. And the diffusion welding does not damage the fins, even if local leakage exists, remedy can be carried out through secondary repair welding, similarly, the damage to the fins is small when the shell is welded, and the product yield is high.

Description

Technical Field

[0001] The invention relates to the field of energy and power technology, and in particular to a core welding structure and welding process of an original surface type heat exchanger. Background Art

[0002] Raw surface heat exchangers are mainly used in distributed micro gas turbines, fuel cells, aircraft engines, etc. They are high-end heat exchanger products. At present, my country does not have mature experience in the design and processing of raw surface heat exchangers, and the raw surface heat exchangers used are all imported products.

[0003] The thickness of the fins used in the original surface heat exchanger is usually only 0.1 to 0.3 mm, and the material is usually stainless steel or high-temperature alloy. The structural forms mainly include Cross-corrugated (CC) type and Cross-wavy (CW) type. A closed flow channel is formed by welding the adjacent fins around, and the welding process is usually argon arc welding and laser welding. CW type fins are deep-drawn corrugated plates, and the fins need to be pressed around to re-form a flat surface for welding with the edge strips. Due to the particularity of the pressing structure, welding is difficult and prone to leakage. CC type fins are formed by one-time integral pressing of the mold. The fin height is relatively short, and the flat area can be retained around the fins for subsequent welding. The existing CC type fin original surface heat exchanger core uses argon arc welding or laser welding. The welding heat affected zone will reduce the performance of the fin material, and when the shell and the pipe are subsequently welded, secondary welding is required at the fin welding site, which causes greater damage to the fins.

[0004] Therefore, it is necessary to provide a core welding structure of an original surface type heat exchanger, which adopts a diffusion welding process to effectively solve the welding problem of ultra-thin metal fins of the original surface type heat exchanger. Summary of the invention

[0005] The purpose of the present invention is to provide a core welding structure and welding process of a surface heat exchanger in view of the shortcomings of the prior art.

[0006] A core welding structure of an original surface type heat exchanger comprises heat exchange fins, a plane area is reserved around the heat exchange fins, and a fume unit side strip and an air circulation unit side strip are placed, and the heat exchange fins at the inlet and outlet of the channel are integrally formed with the fume unit side strip and the air circulation unit side strip by diffusion welding to form a circulation channel;

[0007] The smoke unit side strip is located at the position of the flow channel inlet and outlet to open a smoke inlet and outlet for convenient smoke flow, and a smoke unit etched strip is arranged inside the smoke inlet and outlet;

[0008] The air unit side strip is located at the position of the flow channel inlet and outlet to open an air inlet and outlet for air circulation, and an air unit etching strip is arranged inside the air inlet and outlet;

[0009] Furthermore, the etched slats of the smoke unit are located inside the smoke inlet and outlet to support the slats of the smoke unit, and the heat exchange fins are located at the position of the smoke inlet and outlet and supported by the side strips of the smoke unit to form a smoke circulation unit;

[0010] Furthermore, the upper end of the etched strip of the smoke unit is chemically etched into a flow channel for smoke to pass through, the heat exchange fins are in gapless contact with the edge strip of the smoke unit, and the contact interface is formed into a whole by diffusion welding.

[0011] Furthermore, the upper end of the etched strip of the smoke unit is chemically etched into a wavy surface, the convex part of the wavy surface is in contact with the edge strip of the smoke unit, and the concave part of the wavy surface forms a flow channel for facilitating the passage of smoke.

[0012] Furthermore, the air unit etched slats are located inside the air inlet and outlet to support the air unit slats, and the heat exchange fins are located at the position of the air inlet and outlet and supported by the air unit side strips to form an air circulation unit;

[0013] Furthermore, the upper end of the air unit etched strip is chemically etched into a flow channel for air to pass through, the heat exchange fins are in seamless contact with the air unit side strips, and the contact interface is formed as a whole by diffusion welding.

[0014] Furthermore, the upper end of the air unit etching strip is chemically etched into a wavy surface, the convex part of the wavy surface is in contact with the air unit side strip, and the concave part of the wavy surface forms a flow channel for air to pass through.

[0015] Furthermore, after a plurality of the heat exchange fins are stacked, end plates are installed on the top and the bottom respectively, and a core body is formed by welding through a diffusion welding process.

[0016] Furthermore, it also includes a welding process for welding the original surface type heat exchanger core, welding the original surface type heat exchanger core welding structure as described in any of the above items, the welding process adopts diffusion welding process, and the core is welded and formed as a whole.

[0017] Furthermore, the welding process for welding the original surface heat exchanger core specifically includes the following steps:

[0018] Step 1, assembly: the plane area is reserved around the heat exchange fins, smoke unit side strips are placed at the positions corresponding to the smoke inlet and outlet, air unit side strips are placed at the positions corresponding to the air inlet and outlet, and smoke unit etched strips are arranged in the smoke inlet and outlet of the smoke unit side strips for support, and air unit etched strips are arranged in the air inlet and outlet of the air unit side strips for support;

[0019] Step 2, integrated molding by diffusion welding: the heat exchange fins maintain gapless contact with the flue gas unit side strips and the air unit side strips, the flue gas unit side strips maintain close contact with the flue gas unit etched strips, and the air unit side strips maintain close contact with the air unit etched strips. The contact interfaces are formed as a whole by diffusion welding, which can ensure the sealing of the channel.

[0020] The advantages of the present invention compared with the prior art are:

[0021] 1. This solution adopts diffusion welding process, and all welding interfaces are formed in one time. Compared with the existing products using argon arc welding or laser welding, it reduces the risk brought by uncertain factors in the welding process, and diffusion welding does not damage the fins. Even if there is a local leakage, it can be remedied by secondary repair welding. Similarly, the damage to the fins when welding the shell is also small, and the product yield is high;

[0022] 2. This solution provides etched strips at the inlet and outlet of the flow channel to support the adjacent fins and side strips at the inlet and outlet, so that they fit tightly and have no gap contact, which can ensure the fluidity at the inlet and outlet and the sealing of the diffusion welding interface at the inlet and outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the heat exchange fins of the original surface heat exchanger proposed in this scheme;

[0024] Figure 2 Front view of the etched strips of the original surface heat exchanger proposed for this solution;

[0025] Figure 3 A top view of the etched slats of the original surface heat exchanger proposed for this solution;

[0026] Figure 4 A schematic diagram of the structure of the flue gas circulation unit on the original surface heat exchanger proposed in this scheme;

[0027] Figure 5 The schematic diagram of the structure of the air circulation unit on the original surface heat exchanger proposed in this scheme;

[0028] Figure 6 This is a schematic diagram of the structure of the original surface heat exchanger before the etching strips are set at the inlet and outlet of the flow channel proposed in this scheme;

[0029] Figure 7 This is a schematic diagram of the structure of the original surface heat exchanger after etching strips are set at the inlet and outlet of the flow channel proposed in this scheme;

[0030] Figure 8 A schematic diagram of the structure of the core proposed for this scheme;

[0031] Fig. 9 Schematic diagram of the structure of the core, air and flue gas inlet and outlet proposed for this scheme.

[0032] Figure numerals: 1. heat exchange fin; 2. flue gas unit side strip; 3. flue gas unit etched strip; 4. air unit side strip; 5. air unit etched strip; 6. end plate. DETAILED DESCRIPTION

[0033] Example 1

[0034] This embodiment provides a core welding structure of an original surface type heat exchanger, as shown in the attached specification. Figure 1-9 As shown, it includes a heat exchange fin 1, a flat area is reserved around the heat exchange fin 1, and a smoke unit side strip 2 and an air circulation unit side strip are placed. The heat exchange fin 1 at the inlet and outlet of the channel is integrally formed with the smoke unit side strip 2 and the air unit side strip 4 by diffusion welding to form a circulation channel, as shown in the attached manual Fig. 9 As shown, port A is the air inlet, port B is the air outlet, port C is the smoke inlet, and port D is the smoke outlet;

[0035] After a number of heat exchange fins 1 are stacked, end plates 6 are installed at the top and bottom respectively, and a core body is formed by diffusion welding. Due to the use of diffusion welding technology, the core body is welded as a whole, and there is no need to weld each weld seam separately, which significantly improves efficiency and reduces the risks caused by uncertain factors (such as uneven fins, operation deviations, etc.) when welding a large number of single weld seams;

[0036] Please refer to the instruction manual Figure 4 , 8 9. The smoke unit in this embodiment is specifically described as follows: the smoke unit side strips 2 are located at the position of the flow channel inlet and outlet to open a smoke inlet and outlet to facilitate the inflow and outflow of smoke, and a smoke unit etched strip 3 is arranged inside the smoke inlet and outlet to support the smoke unit side strips 2. The heat exchange fins 1 are located at the position of the smoke inlet and outlet and are supported by the smoke unit side strips 2 to form a smoke flow unit, which is convenient for high-temperature smoke to flow through the smoke flow unit, thereby returning the heat in the smoke to the air.

[0037] Please refer to the instruction manual Figure 2 , 3 , 4, 6, 7, the smoke unit etched strip 3 in this embodiment is specifically described: the upper end of the smoke unit etched strip 3 is chemically etched into a flow channel for smoke to pass through. Specifically in this embodiment, the upper end is etched into a wave surface by chemical etching, and the convex part of the wave surface contacts the smoke unit side strip 2, and the concave part of the wave surface forms a flow channel for smoke to pass through;

[0038] By chemical corrosion, this convex and concave wave-shaped flow channel is etched on the flat plate, which can not only ensure the fluid flowability, but also provide strong support for the heat exchange fins 1 and the flue gas unit edge strips 2, so that the heat exchange fins 1 and the flue gas unit edge strips 2 maintain seamless contact, and the contact interface is formed as a whole by diffusion welding, which can ensure the sealing of the channel and reduce the leakage rate.

[0039] Please refer to the instruction manual Figure 5 , 8 9. The air unit in this embodiment is specifically described as follows: the air unit side strip 4 is located at the position of the flow channel inlet and outlet to open an air inlet and outlet for air circulation, and an air unit etched plate strip 5 is arranged inside the air inlet and outlet to support the air unit plate strip. The heat exchange fin 1 is located at the position of the air inlet and outlet and supported by the air unit side strip 4 to form an air circulation unit;

[0040] When the high-temperature flue gas flows through the flue gas circulation unit, the air also enters the air circulation unit through the air inlet, thereby receiving the heat transferred from the flue gas circulation unit and heating up, thereby achieving a heat exchange effect.

[0041] Please refer to the instruction manual Figure 2 , 3 , 5, 6, 7, the air unit etched strip 5 in this embodiment is specifically described: similar to the smoke unit etched strip 3, the upper end of the air unit etched strip 5 is chemically etched into a flow channel for air to pass through, including but not limited to a wavy surface shape, and any other structure that can achieve the upper convex part contacting the air unit side strip 4 and the concave part facilitating air circulation is acceptable. In this embodiment, the wavy surface shape is specifically used as an example for description, and the convex part of the wavy surface is in contact with the air unit side strip 4, and the concave part of the wavy surface forms a flow channel for air to pass through, the heat exchange fin 1 maintains gapless contact with the air unit side strip 4, and the contact interface is formed as a whole by diffusion welding, which can not only ensure the fluidity of the fluid, but also provide strong support for the fins and side strips at this location, so that the heat exchange fin 1 maintains gapless contact with the smoke unit side strip 2, and is formed as a whole by diffusion welding at the contact interface.

[0042] Example 2

[0043] The present embodiment provides a welding process for welding the core of an original surface type heat exchanger, and welds the original surface type heat exchanger core welding structure as in Embodiment 1. The welding process adopts a diffusion welding process, and the core is welded as a whole, and all welding interfaces are formed at one time, which reduces the risk caused by uncertain factors in the welding process. In addition, diffusion welding does not damage the fins. Even if there is a local leakage, it can be remedied by secondary repair welding. Similarly, the damage to the fins when welding the shell is also small, and the product yield is high.

[0044] In this embodiment, the welding process for welding the original surface heat exchanger core specifically includes the following steps:

[0045] Step 1, assembly: In this embodiment, a CC type heat exchange fin 1 is used, and a plane area is reserved around the CC type heat exchange fin 1. Smoke unit side strips 2 are placed at positions corresponding to the smoke inlet and outlet on the four sides, and air unit side strips 4 are placed at positions corresponding to the air inlet and outlet on the four sides. Smoke unit etched strips 3 are provided in the smoke inlet and outlet of the smoke unit side strip 2 for support, and air unit etched strips 5 are provided in the air inlet and outlet of the air unit side strip 4 for support;

[0046] Step 2, integrated molding by diffusion welding: the heat exchange fin 1 maintains gapless contact with the flue gas unit side strip 2 and the air unit side strip 4, the flue gas unit side strip 2 maintains close contact with the flue gas unit etched strip 3, and the air unit side strip 4 maintains close contact with the air unit etched strip 5. The contact interfaces are formed as a whole by diffusion welding to ensure the sealing of the channel.

[0047] It is worth emphasizing that: since the gas needs to flow in and out, solid edge strips cannot be placed at the channel inlet and outlet, so a smoke inlet and outlet are opened at the position of the smoke unit edge strip 2 corresponding to the smoke inlet and outlet. Since the heat exchange fin 1 at this location has no support and a large span, when the core is pressurized as a whole by diffusion welding, the fins and edge strips at the channel inlet and outlet are difficult to fit tightly together. Therefore, by arranging smoke unit etched strips 3 and air unit etched strips 5 at the flow channel inlet and outlet, i.e., the smoke inlet and outlet and the air inlet and outlet (the etched strip structure is as in Example 1, which will not be elaborated here), it is possible to ensure fluid flowability and provide strong support for the fins and edge strips at this location, so that the fins and edge strips maintain gapless contact and reduce the leakage rate.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0051] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A core welding structure of an original surface heat exchanger, characterized in that: It comprises a heat exchange fin (1), wherein a plane area is reserved around the heat exchange fin (1), and a smoke unit side strip (2) and an air circulation unit side strip are placed thereon, and the heat exchange fin (1) at the inlet and outlet of the channel is integrally formed with the smoke unit side strip (2) and the air circulation unit side strip by diffusion welding to form a circulation channel; The smoke unit side strip (2) is located at the position of the flow channel inlet and outlet to open a smoke inlet and outlet for facilitating smoke flow, and a smoke unit etched strip (3) is arranged inside the smoke inlet and outlet; The air unit side strip (4) is located at the position of the inlet and outlet of the circulation channel to open an air inlet and outlet for easy air circulation, and an air unit etching strip (5) is arranged inside the air inlet and outlet.

2. The original surface type heat exchanger core welding structure according to claim 1 is characterized in that: The smoke unit etched strips (3) are located inside the smoke inlet and outlet to support the smoke unit strips. The heat exchange fins (1) are located at the position of the smoke inlet and outlet and are supported by the smoke unit side strips (2) to form a smoke circulation unit.

3. The original surface type heat exchanger core welding structure according to claim 2 is characterized in that: The upper end of the smoke unit etched strip (3) is chemically etched into a flow channel for smoke to pass through, the heat exchange fin (1) maintains gapless contact with the smoke unit side strip (2), and the contact interface is formed into a whole by diffusion welding.

4. The original surface type heat exchanger core welding structure according to claim 3 is characterized in that: The upper end of the smoke unit etching strip (3) is chemically etched into a wavy surface, the convex part of the wavy surface is in contact with the smoke unit side strip (2), and the concave part of the wavy surface forms a flow channel that facilitates the passage of smoke.

5. The original surface type heat exchanger core welding structure according to claim 1 is characterized in that: The air unit etched strips (5) are located inside the air inlet and outlet to support the air unit strips. The heat exchange fins (1) are located at the position of the air inlet and outlet and are supported by the air unit side strips (4) to form an air circulation unit.

6. The original surface type heat exchanger core welding structure according to claim 5 is characterized in that: The upper end of the air unit etched strip (5) is chemically etched into a flow channel for air to pass through, the heat exchange fin (1) maintains gapless contact with the air unit side strip (4), and the contact interface is formed into a whole by diffusion welding.

7. The original surface type heat exchanger core welding structure according to claim 6 is characterized in that: The upper end of the air unit etching strip (5) is chemically etched into a wavy surface, the convex part of the wavy surface is in contact with the air unit side strip (4), and the concave part of the wavy surface forms a flow channel for air to pass through.

8. The original surface type heat exchanger core welding structure according to claim 1 is characterized in that: After a plurality of the heat exchange fins (1) are stacked, end plates (6) are installed on the top and bottom respectively, and a core body is formed by welding through a diffusion welding process.

9. A welding process for welding an original surface type heat exchanger core, welding the original surface type heat exchanger core welding structure according to any one of claims 1 to 8, characterized in that: The welding process adopts diffusion welding process, and the core is welded as a whole.

10. A welding process for welding the core of an original surface heat exchanger according to claim 9, characterized in that: The specific steps include: Step 1, assembly: a plane area is reserved around the heat exchange fin (1), smoke unit side strips (2) are placed at positions corresponding to smoke inlets and outlets around the heat exchange fin (1), air unit side strips (4) are placed at positions corresponding to air inlets and outlets around the heat exchange fin (1), and smoke unit etched strips (3) are arranged in the smoke inlet and outlet of the smoke unit side strips (2) for support, and air unit etched strips (5) are arranged in the air inlet and outlet of the air unit side strips (4) for support; Step 2, integrated molding by diffusion welding: the heat exchange fin (1) maintains gapless contact with the flue gas unit side strip (2) and the air unit side strip (4), the flue gas unit side strip (2) maintains close contact with the flue gas unit etched strip (3), and the air unit side strip (4) maintains close contact with the air unit etched strip (5). The contact interfaces are formed as a whole by diffusion welding, which can ensure the sealing of the channel.

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