A plate-fin heat exchanger with brazed gilled tubes

Abstract

A plate-fin heat exchanger with a brazed coil includes a plate bundle (1), which is composed of two or more layer channel units stacked alternately. The plate bundle (1) is characterized in that at least one of the two or more layer channel units is a coil layer channel unit (11). The coil layer channel unit (11) includes a coil (111), multiple supports (112), and multiple connecting strips (113). The supports (112) clamp the straight section of the coil (111) from both sides. The connecting strips (113) are straight strips that are embedded between adjacent supports (112). The multiple supports (112) and multiple connecting strips (113) are assembled to form a plate-like body. After the entire body is brazed, the two sides of the connecting strips (113) are brazed to the adjacent layer channel units so that the supports (112) clamp and fix the coil (111), and the entire coil layer channel unit (11) becomes a whole.

Description

Technical Field

[0001] This invention relates to plate-fin heat exchangers, and more specifically to a plate-fin heat exchanger with brazed coils. Background Technology

[0002] Plate-fin heat exchangers are a type of high-efficiency heat exchanger that uses fins as heat transfer elements. They are characterized by high heat transfer efficiency, compact structure, expandable number of heat exchange channels, high adaptability, and light weight. Therefore, they are widely used in gas-to-gas, gas-to-liquid, and liquid-to-liquid two- or more-channel heat exchange equipment, and are currently commonly used in the field of air separation equipment.

[0003] For existing technology, please refer to the technical standard "NB / T 47006—2019 Aluminum Plate-Fin Heat Exchanger". Standard plate-fin heat exchangers consist of a plate bundle, end caps, nozzles, and supports, etc. The plate bundle is constructed by alternating superimposed and brazed two or more layered channel units. Taking two types of layered channel units as an example, both the first and second types consist of fins, guide vanes, seals, and baffles. Fluid inlets and outlets for each of the two channel units are led out from their respective circumferential sides. Then, end caps are welded along the thickness direction to the side of the plate bundle to enclose the fluid inlets and outlets of the same type of channel unit. Finally, nozzles are welded onto the end caps as the overall inlet and outlet, thus forming a heat exchanger.

[0004] However, existing plate-fin heat exchangers, whose channels are made of aluminum fins, suffer from significant strength reduction at temperatures above 60°C and are not corrosion-resistant. Therefore, existing plate-fin heat exchangers are not pressure-resistant, high-temperature resistant, corrosion-resistant, and prone to clogging, with a maximum withstand capacity of 15 MPa, thus limiting their applications. Consequently, for high-pressure, high-temperature, or corrosive fluids, only coil-type heat exchangers, which are more expensive and have much lower heat transfer efficiency, are currently available on the market. Summary of the Invention

[0005] The purpose of this invention is to provide a plate-fin heat exchanger with brazed coils, which, while retaining the high heat exchange efficiency of the original plate-fin heat exchanger, makes it suitable for high-pressure, high-temperature, or corrosive fluids.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a plate-fin heat exchanger with brazed coils, comprising an integrally brazed plate bundle, which is composed of two or more layer channel units stacked alternately, at least one of the two or more layer channel units being a coil layer channel unit, wherein the coil layer channel unit includes a coil, multiple supports, and multiple connecting strips; the coil is composed of one or more tubes coiled in a plane, and the coil is composed of multiple straight tube sections and multiple elbow sections; each support is provided corresponding to a straight tube section of the coil. Each support consists of two support strips arranged face-to-face, with grooves on the opposite surfaces of the support strips corresponding to the straight section of the coil. The straight section of the coil is accommodated in the grooves of the face-to-face support strips, meaning the support clamps the straight section of the coil from both sides. The connecting strip is a straight plate that is embedded between adjacent supports. The multiple supports and multiple connecting strips are assembled to form a plate-like body. After the entire assembly is brazed, each side of the connecting strip is brazed to the adjacent layer channel unit to clamp and fix the coil, making the entire coil layer channel unit a whole.

[0007] In the above scheme, before the overall brazing is formed, brazing foil is provided between the opposite surfaces of the support strip and in its groove, and the coil is made of a brazing-compatible material or the surface of the coil is coated. After the overall brazing is formed, the groove wall of the support strip and the coil are brazed together as well as between the two support strips.

[0008] In the above scheme, the coil is a single tube coiled on a plane.

[0009] In the above scheme, the coil is composed of multiple parallel and leaning tubes coiled together on a plane.

[0010] Based on the above technical solution, the present invention has the following advantages and effects:

[0011] This invention innovatively transforms a layer channel unit in existing plate-fin heat exchangers into a coil layer channel unit primarily composed of coils. The coils, due to their tubular structure, exhibit improved pressure resistance, and their smooth internal walls resist deposition and blockage. Furthermore, the coils can be fixed by clamping with supports, eliminating the need for brazing in material selection and greatly expanding the range of materials that can be used (other than aluminum, such as copper, high-temperature resistant plastics, stainless steel, titanium, etc.), thereby further enhancing their pressure resistance, temperature resistance, and corrosion resistance. In use, high-temperature, high-pressure, or corrosive fluids can be circulated within the coil layer channel unit, successfully expanding its applicability while retaining the high heat exchange efficiency advantage of the original plate-fin heat exchanger.

[0012] Furthermore, since all components (support strips, connecting strips) in its coil layer channel unit, except for the coil, are strips with equal cross-sections, they can all be made of profiles, making them easy to manufacture and cost-effective. Attached Figure Description

[0013] Appendix Figure 1 This is a three-dimensional schematic diagram of Embodiment 1 of the present invention;

[0014] Appendix Figure 2 This is a three-dimensional schematic diagram of the coil layer channel unit according to Embodiment 1 of the present invention;

[0015] Appendix Figure 3 This is an exploded view of the coil layer channel unit according to Embodiment 1 of the present invention;

[0016] Appendix Figure 4 This is a schematic diagram of a normal layer channel unit according to Embodiment 1 of the present invention;

[0017] Appendix Figure 5 This is a three-dimensional schematic diagram of Embodiment 2 of the present invention.

[0018] In the above figures: 1. Plate bundle; 11. Coil layer channel unit; 111. Coil; 112. Support; 1121. Support strip; 11211. Groove; 113. Connecting strip; 12. Ordinary layer channel unit; 121. Fin; 122. Guide vane; 123. Seal; 124. Partition; 2. End cap; 3. Partition. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0020] Example 1: See Figures 1-4 As shown:

[0021] A plate-fin heat exchanger with brazed coils includes an integrally brazed plate bundle 1 and end caps 2 disposed on the plate bundle 1.

[0022] See Figures 1-4 As shown, the plate bundle 1 is composed of two or more layer channel units stacked alternately. At least one of these layer channel units is a coil layer channel unit 11, while the other channel units are existing ordinary layer channel units 12 composed of fins 121, guide vanes 122, seals 123, and partitions 124. Figure 4 As shown.

[0023] See Figures 1-4 As shown, the coil layer channel unit 11 includes a coil 111, multiple supports 112, and multiple connecting strips 113.

[0024] The coil 111 is a single tube coiled in an S-shape on a plane, and consists of multiple straight pipe sections and multiple elbow sections. Each bracket 112 corresponds to a straight pipe section of the coil 111. Specifically, each bracket 112 consists of two bracket strips 1121 arranged face-to-face, and the opposing surfaces of the bracket strips 1121 have grooves 11211 corresponding to the straight pipe section of the coil 111. The straight pipe section of the coil 111 is accommodated in the grooves 11211 of the face-to-face bracket strips, that is, the brackets 112 clamp the straight pipe section of the coil 111 from both sides. The connecting strips 113 are straight plates that are embedded between adjacent brackets 112. The multiple brackets 112 and multiple connecting strips 113 are assembled to form a plate-like body. After the entire assembly is brazed, the two sides of the connecting strip 113 are brazed to the adjacent layer channel unit so that the bracket 112 clamps and fixes the coil 111, and the entire coil layer channel unit 11 becomes a whole.

[0025] At this point, the connecting strip 113 serves a connecting and supporting function, restricting the relative position of the support strip 1121 so that the support strip 1121 clamps and fixes the coil 111. There can be a small gap between the groove wall of the support strip 1121 and the wall of the coil 111, or the gap can be filled with thermally conductive adhesive. The mating surfaces of the connecting strip 113 and the support strip 1121 can be directly abutted or brazed after brazing foil is applied.

[0026] Specifically, the partition 124 of the ordinary layer channel unit 12 is a composite plate with brazing foil on both sides. Therefore, after brazing, the two sides of the connecting strip 113 are brazed to the partition 124 of the adjacent layer channel unit. The outer side of the support strip 1121 of the bracket 112 is also brazed to the partition 124 of the adjacent layer channel unit. The bracket 112 clamps and fixes the coil 111 from both sides, so that the entire coil layer channel unit 11 becomes a whole.

[0027] To further improve heat transfer efficiency and fixation reliability, brazing foil is provided between the opposite surfaces of the support strip 1121 and in its groove 11211 before the overall brazing is formed. The coil is made of a brazing-compatible material or the surface of the coil is coated. After the overall brazing is formed, the groove wall of the support strip 11211 is brazed to the coil 111 and the two support strips 1121, so that the heat (or cold) of the coil 111 can be directly transferred to the support strip 1121.

[0028] When the outermost layer channel unit of the entire plate-fin heat exchanger is a coil layer channel unit 11, a partition 3 should be added to the outer side of the outermost coil layer channel unit 11.

[0029] In this embodiment, the material selection for the coil 111 does not need to consider brazing; materials other than aluminum (such as copper, high-temperature resistant plastics, stainless steel, titanium, etc.) can be used, thereby further improving its pressure resistance, temperature resistance, or corrosion resistance. During use, high-temperature, high-pressure, or corrosive fluids can be circulated in the coil layer channel unit 11, while low-pressure fluids with no special requirements can be circulated in the ordinary layer channel unit 12. This successfully expands the applicability while retaining the high heat exchange efficiency advantage of the original plate-fin heat exchanger.

[0030] The above embodiment is an example. In practice, the coil 111 can be installed in any other way as long as there are straight pipe sections and elbow sections.

[0031] The above embodiment is an example. The straight pipe sections of the support 112 and the coil 111 are set one-to-one, that is, the groove 11211 on the support bar 1121 of each support 112 is a single one. In practice, the straight pipe sections of the support 112 and the coil 111 can also be set one-to-many, such as one-to-two or one-to-three, and the groove 11211 on the support bar 1121 of each support 112 is multiple.

[0032] Example 2: See Figure 5 As shown:

[0033] A plate-fin heat exchanger with brazed coils includes an integrally brazed plate bundle 1 and end caps 2 disposed on the plate bundle 1. The only difference from the embodiment is that the coil 111 is composed of multiple parallel and leaning tubes coiled together on a plane. Everything else is the same as in Embodiment 1, and will not be repeated here.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A plate-fin heat exchanger with brazed coils, comprising an integrally brazed plate bundle (1), the plate bundle (1) being composed of two or more alternating layer channel units, characterized in that: At least one of the two or more layer channel units is a coil layer channel unit (11), which includes a coil (111), multiple supports (112), and multiple connecting strips (113). The coil (111) is formed by one or more tubes coiled together on a plane, and the coil (111) is composed of multiple straight pipe sections and multiple elbow sections. The coil (111) is made of a material other than aluminum. Each support (112) is provided corresponding to a straight pipe section of the coil (111). Specifically, each support (112) It consists of two support strips (1121) arranged face to face, and the opposite surfaces of the support strips (1121) are provided with grooves (11211) corresponding to the straight pipe section of the coil (111). The straight pipe section of the coil (111) is accommodated in the grooves (11211) of the support strips arranged face to face, that is, the support (112) clamps the straight pipe section of the coil (111) from both sides; the connecting strip (113) is a straight plate strip, which is embedded between adjacent supports (112); the multiple supports (112) and multiple connecting strips (113) are assembled to form a plate-like body; After the entire structure is brazed, the two sides of the connecting strip (113) are brazed to the adjacent layer channel unit so that the bracket (112) clamps and fixes the coil (111), and the entire coil layer channel unit (11) becomes a whole.

2. The plate-fin heat exchanger with brazed coils according to claim 1, characterized in that: Before the overall brazing is formed, brazing foil is provided between the opposite surfaces of the support strip (1121) and in its groove (11211). The coil is made of a brazing material or the surface of the coil is plated. After the overall brazing is formed, the groove wall of the support strip (11211) and the coil (111) are brazed together, as are the two support strips (1121).

3. The plate-fin heat exchanger with brazed coils according to claim 1, characterized in that: The coil (111) is a single tube coiled on a plane.

4. The plate-fin heat exchanger with brazed coils according to claim 1, characterized in that: The coil (111) is composed of multiple parallel and leaning tubes coiled together on a plane.

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