Micro-channel heat exchanger and manufacturing method thereof

Abstract

The invention relates to the technical field of heat exchangers, and discloses a micro-channel heat exchanger and a manufacturing method thereof.According to the heat exchanger, multiple sets of criss-cross channel layers are fixedly arranged between an upper sealing plate and a lower sealing plate, and partition plates are fixedly arranged between the channel layers at intervals; the channel layer comprises a plurality of corrugated strips clamped between the edge strips on the two sides, and corrugations of the corrugated strips face the two sides; the corrugated strips and the edge strips of the vertically adjacent channel layers are arranged in a criss-cross mode, and curve heat exchange runners used for turbulent flow are formed between the adjacent corrugated strips and the partition plates. According to the manufacturing method provided by the invention, the manufacturing process is simple, the flow channels between the corrugated strips can be obtained by stamping or bending, the flow channels are formed without etching by a corrosive liquid, the environment is not polluted, and the cost is relatively low; by optimizing the channel structure of the heat exchanger and adjusting the distance between the corrugated strips, the heat exchange area can be obviously increased; a multi-layer composite structure is adopted, a plurality of heat exchange layers are stacked together, and the heat exchange area can be greatly increased in a limited space.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a microchannel heat exchanger and a manufacturing method thereof. Background Art

[0002] Printed Circuit Heat Exchanger (PCHE) is widely used in petroleum, chemical, pharmaceutical, aerospace and other industries. At present, most microchannel heat exchangers use PCHE as the flow channel. The PCHE heat exchanger flow channel plate uses a mirror plate with extremely small roughness, and the medium flow channel is formed by etching. Then, the multi-layer flow channel plate is stacked and diffusion welded to form an integral heat exchanger, such as Figure 1 Compared with shell and tube heat exchangers, the fluid channels of PCHE heat exchangers are generally millimeter-level microchannels, which have higher heat transfer efficiency and specific surface area. Therefore, PCHE heat exchangers have the characteristics of high density and high heat transfer efficiency.

[0003] Although PCHE heat exchangers have many advantages, their processing technology involves etching channels on the flow plate using photochemical processes. In this process, chemicals that pollute the environment are produced, and the processing cycle is long. In addition, the flow channel size and flow channel spacing on the flow plate are subject to minimum size restrictions, and the excess volume cannot be used more effectively.

[0004] Therefore, the existing PCHE heat exchanger and the process for making the PCHE heat exchanger have the following defects:

[0005] 1. Complex process. The etching process of PCHE flow channel usually requires many steps, and chemical corrosion such as strong acid and strong alkali is required. The cost of the corrosive liquid is high, it pollutes the environment greatly, and the quality requirements of the raw materials of the flow channel plate are very high.

[0006] 2. High production cost. The cost mainly lies in the etching of the flow plate. The material of the flow plate with high mirror surface is stainless steel series, and the etching processing cost is high.

[0007] In addition, if Figure 2 Currently, there are "Ji-shaped plates" on the market that can achieve similar effects, but the "Ji-shaped plates" have lower precision and are only suitable for channels larger than 2mm. Summary of the invention

[0008] In order to overcome or alleviate one or more of the above technical problems, the purpose of the present invention is to provide a microchannel heat exchanger and a manufacturing method thereof. The flow channel form and structure of the microchannel heat exchanger abandon the complex processing technology of the traditional PCHE flow channel, while ensuring the heat exchange efficiency and pressure and temperature resistance, simplifying the manufacturing process and greatly reducing the manufacturing cost of the heat exchanger.

[0009] The present invention provides the following technical solutions:

[0010] On the one hand, the present invention provides a microchannel heat exchanger, in which a plurality of groups of criss-cross channel layers are fixedly provided between upper and lower sealing plates, and partitions are fixedly provided between the channel layers at intervals; the channel layers include a plurality of corrugated strips clamped between side strips, and the corrugations of the corrugated strips face both sides; the corrugated strips and side strips of the upper and lower adjacent channel layers are criss-crossed, and curved heat exchange flow channels for turbulence are formed between adjacent corrugated strips and the partitions.

[0011] According to some embodiments, the sealing plate is a mirror plate with a thickness greater than 10 mm.

[0012] According to some embodiments, the partition is a mirror plate with a thickness of 0.1 to 1 mm.

[0013] According to some embodiments, the surface of the mirror plate is 4K-8K.

[0014] According to some embodiments, the mirror plate is selected from stainless steel plates.

[0015] According to some embodiments, the thickness of the edge strips is the same as the height of the corrugated strips.

[0016] According to some embodiments, the corrugated strip has a thickness ranging from 0.1 to 1 mm and a width ranging from 0.5 to 2 mm.

[0017] According to some embodiments, the inwardly directed corrugations of the edge strips correspond to the same corrugations of the corrugated strips.

[0018] On the other hand, the present invention provides a method for manufacturing the above-mentioned microchannel heat exchanger, which comprises the following steps:

[0019] S1: Place a sealing plate at the bottom, which is a mirror plate with a thickness of more than 10 mm;

[0020] S2: Place a side strip on each side of the sealing plate, and arrange multiple corrugated strips in the middle according to the designed spacing to form a flow channel layer;

[0021] S3: Place another layer of partition, the partition is a mirror plate with a thickness of 0.1 to 1 mm;

[0022] S4: Rotate 90 degrees and place another channel layer according to the steps of S2;

[0023] S5: Execute S2 to S4 in a loop until the designed number of layers is reached, and a sealing plate is placed on the top layer;

[0024] S6: The microchannel heat exchanger is manufactured by integrally welding through vacuum diffusion welding.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a microchannel heat exchanger and a manufacturing method thereof. The microchannel heat exchanger manufactured according to the manufacturing method has a simple manufacturing process. The flow channels between the corrugated strips can be obtained by stamping or bending. The flow channels do not need to be etched with a corrosive liquid and will not pollute the environment. In addition, it has a good advantage in cost control, and both the raw material and the processing fee are greatly reduced compared to the PCHE (printed circuit board heat exchanger) cost.

[0027] In terms of heat exchange, design optimization: By optimizing the heat exchanger channel structure and adjusting the spacing between the corrugated strips, the heat exchange area can be significantly increased. The use of a multi-layer composite structure and stacking multiple heat exchange layers together can greatly increase the heat exchange area within a limited space.

[0028] Optimize fluid channels: Design reasonable fluid channels to ensure that the fluid is evenly distributed in the heat exchanger, and use arc structures in the channels to reduce flow resistance and dead corners, increase fluid flow rate and turbulence, and thus promote heat transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a printed circuit board heat exchanger is provided as background art for the present invention.

[0030] Figure 2 A plate diagram of the "Jizi board" type provided as the background technology of the present invention.

[0031] Figure 3 A schematic structural diagram of a microchannel heat exchanger provided in an embodiment of the present invention.

[0032] Figure 4 A schematic diagram of a corrugated strip provided in an embodiment of the present invention.

[0033] Figure 5 A schematic diagram of a side strip provided by an embodiment of the present invention.

[0034] Figure 6 A layered schematic diagram of a microchannel heat exchanger provided in an embodiment of the present invention.

[0035] In the figure:

[0036] Sealing plate 1, channel layer 2, corrugated strip 2-1, side strip 2-2, first channel layer 21, second channel layer 22, partition plate 3. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the 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 position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "set", "install", "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 an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The present invention utilizes a strip-shaped thin plate and upper and lower partitions through a diffusion welding process to form a high-efficiency, high-pressure and high-temperature resistant microchannel heat exchanger.

[0040] The present invention will be further described below in conjunction with the accompanying drawings.

[0041] Example 1

[0042] This embodiment provides a microchannel heat exchanger, in terms of structure, such as Figure 3 .

[0043] The heat exchanger comprises, from top to bottom, a sealing plate 1 at the top layer, a plurality of crisscross channel layers and a sealing plate 1 at the bottom layer, and a partition plate 3 is arranged between each adjacent channel layer 2. The channel layers 2 are stacked in multiple layers to form a fluid heat exchange flow channel. Figures 4 to 6 The channel layer 2 includes a plurality of corrugated strips 2-1 arranged between the side strips 2-2 on both sides, the corrugations of the corrugated strips 2-1 face both sides, and the corrugations of the side strips 2-2 facing inward have the same shape as the corrugations of the corrugated strips 2-1; the upper and lower adjacent channel layers 2 are arranged in a crisscross pattern. A curved heat exchange flow channel for turbulence is formed between the adjacent corrugated strips 2-1 and the partitions 3.

[0044] like Figure 6In the embodiment, the upper first channel layer 21 and the lower second channel layer 22 are staggered at 90 degrees horizontally and vertically. The corrugated strips 2-1 of this type can be made by using only one mold, which is also convenient for assembly.

[0045] The hot fluid enters the first channel layer 21 of the microchannel heat exchanger through the hot working medium pipe and is evenly distributed; the cold fluid enters the second channel layer 22 through the cold working medium pipe and is evenly distributed. In this way, uniform heat exchange is formed between the first channel layer 21 and the second channel layer 22.

[0046] A single channel layer 2 is supported by side strips 2-2 and a plurality of rows of corrugated strips 2-1 are arranged and combined to form a cross-flow curved medium channel, which greatly increases the heat exchange efficiency.

[0047] The method for manufacturing the heat exchanger comprises the following steps:

[0048] 1) A sealing plate 1 is placed at the bottom. The sealing plate 1 is usually a stainless steel plate with a thickness of more than 10 mm (the final thickness is determined by the strength check during design). Its function is to withstand the high pressure during diffusion welding and to bond the adjacent flow channels to form a seal.

[0049] 2) A side strip 2 - 2 is placed on each side of the bottom sealing plate 1 , and a plurality of corrugated strips 2 - 1 are aligned in the middle according to the designed spacing to form a flow channel layer 2 .

[0050] 3) A partition plate 3 is placed on top. The partition plate 3 is a 0.1-1 mm stainless steel plate that is thinner than the sealing plate 1 (the plate thickness is selected according to the heat exchange requirements). It not only acts as a force transmission body for diffusion welding, but also can separate the hot and cold channels. It forms a bonding seal with the contact surfaces of the upper and lower corrugated strips 2-1 and the edge strips 2-2 through diffusion welding.

[0051] 4) Rotate 90 degrees and place another layer of flow channel layer 2 in the other direction according to step 2).

[0052] 5) Stack the layers one by one according to steps 2) to 4) and assemble according to the designed number of layers, with the top cover plate 1 placed on the top layer.

[0053] 6) Then vacuum diffusion welding is performed to form a complete microchannel heat exchanger.

[0054] In addition to stainless steel plates, the sealing plate 1 and the partition plate 3 may also be made of mirror plates of other materials, and the surface of the mirror plates is 4K-8K.

[0055] The side strip 2-2 is a pressure support for the corrugated strip 2-1 to prevent plastic deformation due to excessive pressure during diffusion welding. The thickness of the side strip 2-2 should be equal to the thickness of the corrugated strip 2-1.

[0056] The corrugated strip 2-1 is a core component, and its appearance is curved, which is convenient for fixing on the partition 3 or the sealing plate 1. Through diffusion welding, a sealing welding is formed with the upper and lower surfaces thereof. The sealing of the two corrugated strips 2-1 and the partition 3 forms a curved flow channel. Such a flow channel form is conducive to the formation of turbulence when the medium passes through, which greatly increases the heat exchange efficiency of the heat exchanger.

[0057] The manufacturing process of the corrugated strip 2-1 is simple. The corrugated strip 2-1 usually has a small thickness (0.1-1mm) and width (0.5-2mm), which makes it have unique advantages in certain applications, such as easy bending, winding and processing. First, the raw material sheet of stainless steel is cut into strips by a cutting machine or wire cutting, and then a mold with a corresponding curvature shape is made, and a press is pressed to form a channel layer 2 composed of several pieces of corrugated strips 2-1 and two side strips 2-2. The two adjacent channel layers 2 are in orthogonal directions, and a partition 3 is provided between the two layers. Several layers are stacked together and a whole microchannel heat exchanger is formed through a vacuum diffusion welding process.

[0058] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A microchannel heat exchanger, wherein a plurality of crisscross channel layers are fixedly provided between upper and lower sealing plates, characterized in that: Partitions are fixedly arranged between the channel layers; the channel layer includes a plurality of corrugated strips clamped between the side strips, and the corrugations of the corrugated strips face the two sides; the corrugated strips and side strips of the upper and lower adjacent channel layers are crisscrossed, and a curved heat exchange flow channel for turbulence is formed between the adjacent corrugated strips and the partitions.

2. The microchannel heat exchanger according to claim 1, characterized in that: The sealing plate is a mirror plate with a thickness greater than 10 mm.

3. The microchannel heat exchanger according to claim 2, characterized in that: The partition is a mirror plate with a thickness of 0.1 to 1 mm.

4. The microchannel heat exchanger according to claim 2 or 3, characterized in that: The surface of the mirror plate is 4K-8K.

5. The microchannel heat exchanger according to claim 4, characterized in that: The mirror plate is selected from a stainless steel plate.

6. The microchannel heat exchanger according to claim 1, characterized in that: The thickness of the edge strips is the same as the height of the corrugated strips.

7. The microchannel heat exchanger according to claim 6, characterized in that: The corrugated strip has a thickness ranging from 0.1 to 1 mm and a width ranging from 0.5 to 2 mm.

8. The microchannel heat exchanger according to claim 6, characterized in that: The inwardly directed corrugations of the edge strips correspond to the same corrugations of the corrugated strips.

9. A method for manufacturing a microchannel heat exchanger according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Place a sealing plate at the bottom, which is a mirror plate with a thickness of more than 10 mm; S2: Place a side strip on each side of the sealing plate, and arrange multiple corrugated strips in the middle according to the designed spacing to form a flow channel layer; S3: Place another layer of partition, the partition is a mirror plate with a thickness of 0.1 to 1 mm; S4: Rotate 90 degrees and place another channel layer according to the steps of S2; S5: Execute S2 to S4 in a loop until the designed number of layers is reached, and a sealing plate is placed on the top layer; S6: The microchannel heat exchanger is manufactured by integrally welding through vacuum diffusion welding.

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