Welding tooling, heat exchanger welding method and heat exchanger

Abstract

The present application provides a welding tooling, a heat exchanger welding method and a heat exchanger. The welding tooling includes: a base, which is matched with the sleeve; a first groove is provided at the side wall corner of the base close to the first folded edge; a clamping plate, which is detachably installed outside the first groove and covers the first groove; an opening groove is provided at the edge of the clamping plate close to the first folded edge, the orthographic projection of the abutting position of the first folded edge and the second folded edge on the first groove is a first projection, the orthographic projection of the opening groove on the first groove is a second projection, and the first projection is located within the second projection; a gas supply unit, which is used to provide a shielding gas to the abutting position of the first folded edge and the second folded edge; a cooling unit, which is used to reduce the temperature of the welding tooling. The welding tooling, the heat exchanger welding method and the heat exchanger provided by the present application have a simple structure, convenient welding operation, can effectively improve the flatness of the sealing surface after welding, improve the sealing effect of the heat exchanger, and improve the service life.

Description

Technical Field

[0001] The present application relates to the technical field of heat exchangers, and particularly to a welding tooling, a heat exchanger welding method and a heat exchanger. Background Art

[0002] A heat exchanger is a device that transfers part of the heat of a hot fluid to a cold fluid, and plays an important role in many industrial productions such as chemical industry, petroleum, power, food and others. Among them, the plate-frame heat exchanger, due to its compact design, flexible modular combination and structure convenient for mechanical cleaning, combines the high heat transfer performance of the detachable plate heat exchanger and the high pressure-bearing performance of the welded plate heat exchanger, and can ensure the long-term efficient and stable operation of the heat exchanger, making its application in high-temperature, high-pressure and highly corrosive medium working conditions more and more extensive.

[0003] The material of the pressure-bearing component of the plate-frame heat exchanger is usually carbon steel, and the material of the flow-through component is usually corrosion-resistant materials such as stainless steel and super stainless steel. In order to avoid the fluid of the flow-through component from corroding the pressure-bearing component, a sealing surface component made of the same material as the flow-through component is generally used to cover the pressure-bearing component.

[0004] As Figure 1 shown in the structural schematic diagram of the plate-frame heat exchanger, the heat exchanger includes a core plate bundle, that is, a flow-through component for fluid heat exchange; the core plate bundle is arranged in a frame composed of columns, a pressing plate and a cover plate, and the columns, the pressing plate and the cover plate are the pressure-bearing components; a sleeve is arranged between the core plate bundle and the columns, and a first folded edge is arranged on the vertical edge of the sleeve to cover the columns; a bearing plate is arranged between the core plate bundle and the pressing plate, and a second folded edge is arranged on the edge of the bearing plate to cover the pressing plate; the sleeve and the bearing plate are the sealing surface components, and the ends of the first folded edge and the second folded edge are butt-welded to form a rectangular sealing surface as a whole. The cover plate is used to close the rectangular sealing surface, and a sealing gasket is arranged between the cover plate and the rectangular sealing surface.

[0005] The sealing performance between the core plate bundle and the frame is the key to the high pressure resistance of the heat exchanger product, which will directly affect the operation of the equipment. In actual use, the heat exchanger often leaks at the sealing gasket. Therefore, there is an urgent need for a heat exchanger with stronger sealing performance.

[0006] Most of the existing gaskets are hard gaskets such as graphite and polytetrafluoroethylene with low compression rate and poor fluidity. This requires the rectangular sealing surface to be flat and smooth to avoid local gaps causing leakage. During the implementation of this application, it is found that the leakage positions of the gasket mainly concentrate on the welding joint of the first folded edge and the second folded edge. This position is often at a different height from other positions. The reason for this phenomenon is that the existing first folded edge and second folded edge are connected by a welding technique of single-sided welding and double-sided forming. This method will leave a certain amount of weld bead on the back of the joint, increasing the height of the sealing surface at this place and causing leakage. If the weld bead is removed by grinding, not only does it increase the process operation, but also the process requirements for grinding are extremely high, and it is easy to thin the sealing surface at this place. The overall sealing surface is still uneven and the thickness is uneven, which will also cause leakage. In view of this situation, a welding tooling can be considered to assist in the welding of the first folded edge and the second folded edge to ensure the flatness of the overall sealing surface and avoid leakage at the gasket. Summary of the Invention

[0007] In view of this, the purpose of this application is to provide a welding tooling, a heat exchanger welding method and a heat exchanger to solve the related problems mentioned in the background technology.

[0008] In the first aspect of this application, a welding tooling is provided, which is applied to the welding of a heat exchanger. The heat exchanger includes a core plate bundle. The top and bottom of the core plate bundle are respectively provided with bearing plates. The side corners of the core plate bundle are provided with sleeves. The sleeve is located between the two bearing plates. The vertical edge of the sleeve is provided with a first folded edge. The edge of the bearing plate is provided with a second folded edge. The ends of the first folded edge and the second folded edge are abutted against each other. The welding tooling includes: a base, which is matched with the sleeve and used to be embedded in the sleeve; a first groove is provided at the side corner of the base close to the first folded edge, and the first groove is used to accommodate the first folded edge and the second folded edge; a clamping plate, which is detachably installed outside the first groove and covers the first groove, and is used to simultaneously press the first folded edge and the second folded edge; an opening groove is provided at the edge of the clamping plate close to the first folded edge. The orthographic projection of the abutting joint of the first folded edge and the second folded edge on the first groove is a first projection, and the orthographic projection of the opening groove on the first groove is a second projection. The first projection is located within the second projection; a gas supply unit, which is installed on the base and used to provide a protective gas to the abutting joint of the first folded edge and the second folded edge; a cooling unit, which is installed on the base and used to reduce the temperature of the welding tooling.

[0009] Further, the thickness of the first folded edge is equal to the thickness of the second folded edge, and the depth of the first groove is less than or equal to the thickness of the first folded edge.

[0010] Furthermore, a second groove is provided at the bottom of the first groove, a ceramic cushion block is fitted in the second groove, and the depth of the second groove is equal to the thickness of the ceramic cushion block; the orthographic projection of the second groove on the first groove is a third projection, and the second projection is located within the third projection.

[0011] Furthermore, notches are provided at the corners of the base close to the core plate bundle. The gas supply unit includes: a first channel provided on the side wall of the base and vertically penetrating the bottom of the second groove; a second channel provided in the base and vertically penetrating the first channel; a third channel provided in the base, one end of which penetrates the side wall of the notch and the other end penetrates the second channel; an inlet pipe provided in the notch and communicated with the port of the third channel for conveying a protective gas.

[0012] Furthermore, the first flanges are provided at both side edges of the sleeve along the first horizontal direction, and the first grooves and the clamping plates are provided at both side corners of the base along the first horizontal direction.

[0013] Furthermore, the gas supply units are provided on both sides of the notch along the first horizontal direction, a tee pipe is connected between the inlet pipes of the two gas supply units, the tee pipe is provided in the notch, and the branch pipe of the tee pipe is connected to a gas source.

[0014] Furthermore, a plurality of vertical through holes are provided at intervals in the base, and the plurality of vertical through holes are axially symmetrically distributed along a second horizontal direction perpendicular to the first horizontal direction. The cooling unit includes a cooling pipe that sequentially penetrates through the plurality of vertical through holes for providing a coolant.

[0015] Furthermore, the clamping plate is connected to the base by bolts, and the ceramic cushion block is connected to the base by bolts or adhesives.

[0016] In the second aspect of the present application, a heat exchanger welding method is provided, using the welding tooling described in the first aspect above. The heat exchanger welding method includes: fitting the base into the inner end of the sleeve; opening the gas supply unit, installing the clamping plate on the base, and simultaneously pressing the first flange and the second flange to fix the welding tooling on the heat exchanger and expose the abutting portion of the first flange and the second flange through the opening groove; opening the cooling unit to weld the abutting portion of the first flange and the second flange; closing the gas supply unit and the cooling unit, and disassembling the clamping plate to separate the welding tooling from the heat exchanger.

[0017] In a third aspect of the present application, a heat exchanger is provided, which is obtained by welding using the heat exchanger welding method described in the second aspect above.

[0018] As can be seen from the above description, the welding tooling, the heat exchanger welding method, and the heat exchanger provided by the present application, the welding tooling is applied to the welding of the heat exchanger, and includes: a base, which is matched with the sleeve and used for fitting into the sleeve; a first groove is provided at the side wall corner of the base close to the first folded edge, and the first groove is used for accommodating the first folded edge and the second folded edge; a clamping plate, which is detachably installed outside the first groove and covers the first groove, and is used for simultaneously pressing the first folded edge and the second folded edge, on the one hand, avoiding the deformation of the first folded edge and the second folded edge due to heat during welding, and on the other hand, making the back surfaces of the first folded edge and the second folded edge closely cooperate with the base, so that the weld bead can be flush with the back surface of the sealing surface and no reinforcement will be generated; an opening groove is provided at the edge of the clamping plate close to the first folded edge, the projection of the contact position of the first folded edge and the second folded edge on the first groove is the first projection, and the projection of the opening groove on the first groove is the second projection, and the first projection is located within the second projection, providing space for welding the first folded edge and the second folded edge; a gas supply unit, which is installed on the base and used for supplying protective gas to the contact position of the first folded edge and the second folded edge, avoiding oxidation of the back surface of the sealing surface during welding, reducing the welding quality and generating height differences; a cooling unit, which is installed on the base and used for reducing the temperature of the welding tooling, reducing the residence time in the sensitization temperature range, avoiding intergranular corrosion at the welding position, and ensuring the mechanical strength and sealing performance of the sealing surface; when the welding tooling is in use, the base can be first embedded in the sleeve of the heat exchanger, the gas supply unit is turned on to evacuate the air, avoiding oxidation due to air residue on the back surface of the sealing surface, then the clamping plate is installed to clamp the first folded edge and the second folded edge simultaneously, and the aforementioned contact position is exposed through the opening groove, after the cooling unit is turned on, welding is carried out, and no weld bead reinforcement will be generated on the back surface of the sealing surface after welding, there is no need to polish the back surface, improving the work efficiency, ensuring the flatness of the sealing surface after welding, and further avoiding leakage at the gasket; the welding tooling, the heat exchanger welding method, and the heat exchanger have simple structures, convenient welding operations, can effectively improve the flatness of the sealing surface after welding, improve the sealing effect of the heat exchanger, and improve the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present application or related technologies, the following will briefly introduce the drawings required to be used in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a three-dimensional structure schematic diagram of a heat exchanger;

[0021] Figure 2 Schematic enlarged structure diagram of the cooperation between the first hemming and the second hemming;

[0022] Figure 3 Schematic three-dimensional structure diagram of a welding fixture;

[0023] Figure 4 Schematic three-dimensional structure diagram of the cooperation between the welding fixture and the heat exchanger;

[0024] Figure 5 Schematic cross-sectional structure diagram of the cooperation between the welding fixture and the heat exchanger;

[0025] Figure 6 Schematic diagram of the orthographic projection of the abutting position of the first hemming and the second hemming on the first groove.

[0026] Reference numerals: 1, core plate bundle; 2, bearing plate; 2-1, second hemming; 3, sleeve; 3-1, first hemming; 4, column; 5, pressing plate; 6, cover plate; 7, base; 7-1, first groove; 7-2, second groove; 7-3, notch; 7-4, vertical through hole; 8, clamping plate; 8-1, opening groove; 9, air supply unit; 9-1, first channel; 9-2, second channel; 9-3, third channel; 9-4, inlet pipe; 9-5, tee; 10, cooling unit; 10-1, cooling pipe; 11, ceramic spacer; 12, first projection; 13, second projection; 14, third projection. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the following further elaborates on the present application in detail with reference to specific embodiments and the accompanying drawings.

[0028] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the ordinary meanings understood by those of ordinary skill in the art to which the present application pertains. The "first", "second" and similar terms used in the embodiments of the present application do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0029] A heat exchanger is a device that transfers part of the heat of a hot fluid to a cold fluid. It plays an important role in many industrial productions such as chemical industry, petroleum, power, food and others. Among them, the plate-frame heat exchanger, due to its compact design, flexible modular combination and structure convenient for mechanical cleaning, combines the high heat transfer performance of the detachable plate heat exchanger and the high pressure-bearing performance of the welded plate heat exchanger, which can ensure the long-term efficient and stable operation of the heat exchanger, making its application in high-temperature, high-pressure and highly corrosive medium working conditions more and more extensive.

[0030] The material of the pressure-bearing components of the plate-frame heat exchanger is usually carbon steel, and the material of the flow-through components is usually corrosion-resistant materials such as stainless steel and super stainless steel. In order to avoid the fluid of the flow-through components from corroding the pressure-bearing components, a sealing surface component made of the same material as the flow-through components is generally used to cover the pressure-bearing components; as Figure 1 shown in the structural schematic diagram of the plate-frame heat exchanger, the heat exchanger includes a core plate bundle 1, that is, the flow-through component, for fluid heat exchange; the core plate bundle 1 is arranged in a frame composed of columns 4, a pressing plate 5 and a cover plate 6, and the columns 4, the pressing plate 5 and the cover plate 6 are the pressure-bearing components; a sleeve 3 is arranged between the core plate bundle 1 and the column 4, and a first folded edge 3-1 is provided at the vertical edge of the sleeve 3, and the first folded edge 3-1 covers the column 4; a bearing plate 2 is arranged between the core plate bundle 1 and the pressing plate 5, and a second folded edge 2-1 is provided at the edge of the bearing plate 2, and the second folded edge 2-1 covers the pressing plate 5; the sleeve 3 and the bearing plate 2 are the sealing surface components, as Figure 2 shown, the ends of the first folded edge 3-1 and the second folded edge 2-1 are butted and welded to form a rectangular sealing surface as a whole, and the cover plate 6 is used to close the rectangular sealing surface, and a gasket is arranged between the cover plate 6 and the rectangular sealing surface.

[0031] The sealing performance between the core plate bundle 1 and the frame is the key to the high pressure resistance of the heat exchanger product and will directly affect the operation of the equipment. In actual use, the heat exchanger often leaks at the gasket, so there is an urgent need for a heat exchanger with stronger sealing performance.

[0032] Existing gaskets are mostly hard gaskets with low compression rates and poor fluidity, such as graphite and polytetrafluoroethylene. This requires the rectangular sealing surface to be flat and smooth to avoid local gaps causing leakage. During the implementation of this application, it was found that the leakage position of the gasket mainly concentrated at the welding joint of the first folded edge 3-1 and the second folded edge 2-1. The height of this position is often different from other positions. The reason for this phenomenon is that the existing first folded edge 3-1 and second folded edge 2-1 are connected by a welding technique of single-sided welding and double-sided forming. This method will leave a certain amount of weld bead on the back of the joint, increasing the height of the sealing surface at this place and causing leakage. If the weld bead is removed by grinding, not only does it increase the process operation, but also the process requirements for grinding are extremely high, and it is easy to thin the sealing surface at this place. The overall sealing surface is still uneven and the thickness is uneven, which will also cause leakage. In addition, under the welding conditions without fixture cooperation, the first folded edge 3-1 and the second folded edge 2-1 are also prone to warping and deformation due to the influence of welding heat, further increasing the impact on the flatness of the sealing surface. In response to this situation, a welding fixture can be considered to assist the welding of the first folded edge 3-1 and the second folded edge 2-1 to ensure the overall flatness of the sealing surface and avoid leakage at the gasket.

[0033] The following will be described in detail the technical solution of this application through specific embodiments in combination with Figures 1 to 5 to illustrate.

[0034] In some embodiments of this application, a welding fixture is provided, which is applied to the welding of a heat exchanger, such as Figure 1 and Figure 2 shown. The heat exchanger includes a core plate bundle 1. Support plates 2 are respectively provided at the top and bottom of the core plate bundle 1. A sleeve 3 is provided at the side corner of the core plate bundle 1. The sleeve 3 is located between the two support plates 2. A first folded edge 3-1 is provided at the vertical edge of the sleeve 3. A second folded edge 2-1 is provided at the edge of the support plate 2. The ends of the first folded edge 3-1 and the second folded edge 2-1 are in contact; as Figure 3 and Figure 4As shown in the figure, the welding tooling includes: a base 7, which is matched with the sleeve 3 and is used to fit inside the sleeve 3; a first groove 7-1 is provided at the side wall corner of the base 7 close to the first folded edge 3-1, and the first groove 7-1 is used to accommodate the first folded edge 3-1 and the second folded edge 2-1; a clamping plate 8, which is detachably installed outside the first groove 7-1 and covers the first groove 7-1, and is used to simultaneously press the first folded edge 3-1 and the second folded edge 2-1; an opening groove 8-1 is provided at the edge of the clamping plate 8 close to the first folded edge 3-1, the projection of the contact position of the first folded edge 3-1 and the second folded edge 2-1 on the first groove 7-1 is a first projection 12, the projection of the opening groove 8-1 on the first groove 7-1 is a second projection 13, and the first projection 12 is located inside the second projection 13; a gas supply unit 9, which is installed on the base 7 and is used to provide a shielding gas to the contact position of the first folded edge 3-1 and the second folded edge 2-1; a cooling unit 10, which is installed on the base 7 and is used to reduce the temperature of the welding tooling.

[0035] As Figure 1 shown, the heat exchanger includes a core plate bundle 1, and the core plate bundle 1 is used for fluid heat exchange; bearing plates 2 are respectively provided at the top and bottom of the core plate bundle 1, and the bearing plates 2 are used to protect the pressing plate 5 to prevent fluid leakage and corrosion of the pressing plate 5; a sleeve 3 is provided at the side wall corner of the core plate bundle 1, and the sleeve 3 is used to protect the column 4 to prevent fluid leakage and corrosion of the column 4; the sleeve 3 is located between the two bearing plates 2, a first folded edge 3-1 is provided at the vertical edge of the sleeve 3, a second folded edge 2-1 is provided at the edge of the bearing plate 2, and the ends of the first folded edge 3-1 and the second folded edge 2-1 are abutted to form a sealing surface for cooperating with the cover plate 6.

[0036] As Figure 3 shown, the welding tooling includes a base 7, the material of the base 7 is, for example, alloy steel, the base 7 is matched with the sleeve 3 and is used to fit inside the sleeve 3, the cross-sectional shape of the base 7 can be the same as the cross-sectional shape of the column 4, and the thickness is, for example, 70 mm, and the specific value is not limited.

[0037] A first groove 7-1 is provided at the side wall corner of the base 7 close to the first folded edge 3-1, and the first groove 7-1 is used to accommodate the first folded edge 3-1 and the second folded edge 2-1.

[0038] The material of the splint 8 is, for example, alloy steel, and it can be detachably installed outside the first groove 7-1, for example, by the cooperation of bolts and threaded holes. The splint 8 covers the first groove 7-1 and is used to press the first folded edge 3-1 and the second folded edge 2-1 simultaneously. On the one hand, it can play a fixing role to prevent the first folded edge 3-1 and the second folded edge 2-1 from being deformed by heat during welding and ensure flatness; on the other hand, it makes the back surfaces of the first folded edge 3-1 and the second folded edge 2-1 fit tightly with the base 7, so that the weld bead can be flush with the back surface of the sealing surface after welding, without generating a reinforcement height, further ensuring the flatness of the welding joint.

[0039] An opening groove 8-1 is provided at the edge of the splint 8 close to the first folded edge 3-1. The opening groove 8-1 is, for example, a U-shaped groove. As Figure 6 shown, the orthographic projection of the abutting position of the first folded edge 3-1 and the second folded edge 2-1 on the first groove 7-1 is the first projection 12, and the orthographic projection of the opening groove 8-1 on the first groove 7-1 is the second projection 13. The first projection 12 is located within the second projection 13, exposing the abutting position of the first folded edge 3-1 and the second folded edge 2-1 to provide space for welding.

[0040] The gas supply unit 9 is installed on the base 7 and is used to supply a shielding gas to the abutting position of the first folded edge 3-1 and the second folded edge 2-1. The shielding gas is, for example, argon, to prevent oxidation of the back surface of the sealing surface during welding, reduce the welding quality, or generate height differences.

[0041] The cooling unit 10 is installed on the base 7 and is used to reduce the temperature of the welding tooling. For 300 series austenitic stainless steel, super austenitic stainless steel or special sealing surface metal materials, it can accelerate the cooling speed, reduce the residence time in the sensitization temperature range, prevent intergranular corrosion at the welding joint, and ensure the mechanical strength and sealing performance of the sealing surface.

[0042] As Figure 4 shown, when this welding tooling is in use, the base 7 can be first embedded in the sleeve 3 of the heat exchanger, and the gas supply unit 9 is turned on to evacuate the air to prevent oxidation due to air residue on the back surface of the sealing surface. Then, the splint 8 is installed to clamp the first folded edge 3-1 and the second folded edge 2-1 simultaneously, and the aforementioned abutting position is exposed through the opening groove 8-1. After turning on the cooling unit 10, welding is performed on the front surface of the sealing surface. After welding, there will be no weld bead reinforcement height and surface oxidation on the back surface of the sealing surface, and there is no need to perform grinding operations on the back surface, improving work efficiency and ensuring the flatness of the sealing surface after welding. In this way, the sealing surface can fit tightly with the gasket, preventing leakage at the gasket.

[0043] This welding tooling has a simple structure and convenient welding operation, can effectively improve the flatness of the sealing surface after welding, improve the sealing effect of the heat exchanger, and extend the service life.

[0044] In some embodiments, the thickness of the first hem 3-1 is equal to the thickness of the second hem 2-1, and the depth of the first groove 7-1 is less than or equal to the thickness of the first hem 3-1.

[0045] The equal thickness of the first hem 3-1 and the second hem 2-1 ensures the flatness of the formed sealing surface.

[0046] The depth of the first groove 7-1 is, for example, from 1 mm to 20 mm, and the cross-sectional area is, for example, 30 mm * 20 mm, without specific limitation. The depth of the first groove 7-1 is less than or equal to the thickness of the first hem 3-1. For example, the thickness of the first hem 3-1 is 1 to 1.2 times the depth of the first groove 7-1. This facilitates the clamping of the first hem 3-1 and the second hem 2-1 after the clamping plate 8 and the first groove 7-1 cooperate, and avoids the situation where the depth of the first groove 7-1 is too shallow, causing the clamping plate 8 to tilt too much when clamping the first hem 3-1 and the second hem 2-1, resulting in uneven clamping force and affecting the welding quality. It also avoids the situation where the depth of the first groove 7-1 is too deep, causing looseness when clamping the first hem 3-1 and the second hem 2-1.

[0047] In some embodiments, as Figure 6 shown, the first projection 12 is located within the first groove 7-1, ensuring that the end of the abutting portion of the first hem 3-1 and the second hem 2-1 can be welded in place.

[0048] In some embodiments, as Figure 3 and Figure 5 shown, a second groove 7-2 is provided at the bottom of the first groove 7-1, and a ceramic pad 11 is fitted in the second groove 7-2. The depth of the second groove 7-2 is equal to the thickness of the ceramic pad 11; as Figure 6 shown, the orthographic projection of the second groove 7-2 on the first groove 7-1 is a third projection 14, and the second projection 13 is located within the third projection 14.

[0049] When welding the sealing surfaces of titanium and titanium alloy materials, nickel and nickel-based alloy materials, if directly welded on the base 7, different degrees of carburization, nitriding, etc. will occur. Carbon atoms or nitrogen atoms will penetrate into the surface layer of the sealing surface, resulting in the formation of carbonitrides or alloy compounds in the weld, reducing the mechanical properties and corrosion resistance of the weld, and at the same time increasing the risk of sealing surface cracking.

[0050] As Figure 3As shown, a second groove 7-2 is provided at the bottom of the first groove 7-1. The volume of the second groove 7-2 is, for example, 30mm * 20mm * 15mm, and is not specifically limited. A ceramic spacer 11 is fitted in the second groove 7-2. The ceramic spacer 11 is, for example, a high-temperature resistant ceramic material. By providing the ceramic spacer 11, direct contact between the base 7 and the welding area can be avoided, effectively preventing phenomena such as carburization and nitriding. The depth of the second groove 7-2 is equal to the thickness of the ceramic spacer 11. The ceramic spacer 11 can be connected by means of a countersunk bolt cooperating with a threaded hole, or fixed by industrial adhesive, ensuring the flatness of the bottom of the first groove 7-1, and thus ensuring the flatness of the first folded edge 3-1 and the second folded edge 2-1. As Figure 6 shown, the orthographic projection of the second groove 7-2 on the first groove 7-1 is a third projection 14, and the second projection 13 is located within the third projection 14, so that the welding areas are all located on the ceramic spacer 11, ensuring the welding quality.

[0051] In some embodiments, as Figure 3 and Figure 5 shown, a notch 7-3 is provided at the corner of the base 7 close to the core plate bundle 1. The gas supply unit 9 includes: a first channel 9-1 provided on the side wall of the base 7 and vertically penetrating the bottom of the second groove 7-2; a second channel 9-2 provided in the base 7 and vertically penetrating the first channel 9-1; a third channel 9-3 provided in the base 7, one end of which penetrates the side wall of the notch 7-3 and the other end penetrates the second channel 9-2; and an inlet pipe 9-4 provided in the notch 7-3 and communicating with the port of the third channel 9-3 for transporting protective gas.

[0052] As Figure 5 shown, a notch 7-3 is provided at the corner of the base 7 close to the core plate bundle 1, providing space for the gas supply unit 9 to connect to the gas source, enabling the gas supply unit 9 to be arranged close to the core plate bundle 1, and avoiding the structural position of the gas supply unit 9 interfering with the position of the first groove 7-1 and affecting the welding effect.

[0053] The gas supply unit 9 includes a first channel 9-1, a second channel 9-2, a third channel 9-3, and an intake pipe 9-4 that are sequentially connected. The first channel 9-1 is provided on the side wall of the base 7 and vertically penetrates the bottom of the second groove 7-2; the second channel 9-2 is provided inside the base 7 and vertically penetrates the first channel 9-1; the third channel 9-3 is provided inside the base 7, one end penetrates the side wall of the notch 7-3, and the other end penetrates the second channel 9-2; the intake pipe 9-4 is provided in the notch 7-3 and communicates with the port of the third channel 9-3 for transporting protective gas; the gas supply unit 9 is convenient to manufacture. The protective gas enters from the intake pipe 9-4, passes through the third channel 9-3 and the second channel 9-2, and is discharged from the first channel 9-1. The protective gas reaches the back of the sealing surface along the gap between the second groove 7-2 and the ceramic spacer 11 or the gap between the base 7 and the sleeve 3 to protect the welding at this place.

[0054] In some embodiments, as Figure 3 and Figure 4 shown, both side edges of the sleeve 3 along the first horizontal direction are provided with the first flanges 3-1, and both side corners of the base 7 along the first horizontal direction are provided with the first grooves 7-1 and the clamping plates 8.

[0055] As Figure 4 shown, in the figure, the L1 direction is the first horizontal direction, and the L2 direction is the second horizontal direction. Both side edges of the sleeve 3 along the first horizontal direction are provided with the first flanges 3-1, and both side corners of the base 7 along the first horizontal direction are provided with the first grooves 7-1 and the clamping plates 8. In this way, after the welding tooling is installed on the sleeve 3, the welding can be carried out on the abutting parts of the sealing surfaces on both sides. One installation can perform two weldings, or even weld on both sides simultaneously, greatly improving the welding efficiency.

[0056] In some embodiments, as Figure 5 shown, the gas supply units 9 are provided on both sides of the notch 7-3 along the first horizontal direction. A tee pipe 9-5 is connected between the intake pipes 9-4 of the two gas supply units 9. The tee pipe 9-5 is provided in the notch 7-3, and the branch pipe of the tee pipe 9-5 is connected to a gas source.

[0057] As Figure 5 shown, a gas supply unit 9 is provided on each side of the notch 7-3 along the first horizontal direction. A tee pipe 9-5 is connected between the intake pipes 9-4 of the two gas supply units 9. The tee pipe 9-5 is provided in the notch 7-3, and the branch pipe of the tee pipe 9-5 is connected to a gas source. In this way, one gas source can supply gas to the two gas supply units 9 at the same time to protect the welding of the abutting parts of the sealing surfaces on both sides of the sleeve 3, and provide a basis for welding on both sides simultaneously, further shortening the manufacturing cycle of the heat exchanger; the two gas supply units 9 are axially symmetrically distributed along the second horizontal direction to ensure the consistency of the welding quality.

[0058] In some embodiments, as Figure 4 and Figure 5 shown, a plurality of vertical through holes 7-4 are provided at intervals in the base 7, and the plurality of vertical through holes 7-4 are axially symmetrically distributed along a second horizontal direction perpendicular to the first horizontal direction. The cooling unit 10 includes a cooling pipe 10-1, and the cooling pipe 10-1 sequentially passes through the plurality of vertical through holes 7-4 for providing a coolant.

[0059] As Figure 4 and Figure 5 shown, a plurality of vertical through holes 7-4 are provided at intervals in the base 7, with a hole diameter of, for example, 10 mm. The vertical through holes 7-4 are used to accommodate the cooling pipe 10-1 to facilitate the cooling of the base 7 by the coolant; the plurality of vertical through holes 7-4 are axially symmetrically distributed along the second horizontal direction to ensure that the cooling effects at the abutting joints of the two sealing surfaces are similar, so as to ensure the consistency of the welding quality and further ensure the flatness of the sealing surface; the cooling unit 10 includes a cooling pipe 10-1, such as a U-shaped pipe, and the cooling pipe 10-1 sequentially passes through the plurality of vertical through holes 7-4 for providing a coolant, and the coolant is, for example, water, and is not specifically limited.

[0060] In some embodiments of the present application, a heat exchanger welding method is provided, using the welding tooling described in any of the above embodiments. The heat exchanger welding method includes:

[0061] S1. Fit the base 7 into the inner end of the sleeve 3.

[0062] S2. Turn on the air supply unit 9, install the clamping plate 8 on the base 7, and simultaneously press the first folded edge 3-1 and the second folded edge 2-1 to fix the welding tooling on the heat exchanger, and expose the abutting joint of the first folded edge 3-1 and the second folded edge 2-1 through the opening groove 8-1.

[0063] Turn on the air supply unit 9 for a certain period of time to ensure that the air in the gaps between the ceramic pads 11 and the first folded edge 3-1 and the second folded edge 2-1 is exhausted to avoid surface oxidation.

[0064] S3. Turn on the cooling unit 10 to weld the abutting joint of the first folded edge 3-1 and the second folded edge 2-1.

[0065] S4. Turn off the air supply unit 9 and the cooling unit 10, remove the clamping plate 8, and separate the welding tooling from the heat exchanger.

[0066] The heat exchanger obtained by this method has a flat back surface of the sealing surface, and there is no need to polish the back surface. If there is a weld bead height remaining on the front surface of the sealing surface, only the front surface can be polished after removing the welding tooling. Compared with the related art where both the front and back surfaces are polished, the operation difficulty is greatly reduced and the work efficiency is improved; this heat exchanger welding method enables the sealing surface to fit tightly with the gasket, and there will be no leakage at the weld between the first folded edge 3-1 and the second folded edge 2-1.

[0067] In some embodiments of the present application, a heat exchanger is provided, which is welded and obtained by using the heat exchanger welding method described in any of the above embodiments.

[0068] This heat exchanger has a simple structure, is easy to manufacture, has a good sealing effect, and a long service life.

[0069] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of brevity.

[0070] In addition, in the case of elaborating the details to describe the exemplary embodiments of the present application, it is obvious to those skilled in the art that the present application embodiments can be implemented without these details or with variations of these details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0071] Although the present application has been described in combination with the embodiments of the present application, according to the previous description, many substitutions, modifications, and variations of these embodiments will be obvious to those of ordinary skill in the art.

[0072] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A welding fixture, characterized in that it is applied to the welding of a heat exchanger, the heat exchanger includes a core plate bundle, bearing plates are respectively arranged at the top and bottom of the core plate bundle, sleeves are arranged at the side corners of the core plate bundle, the sleeves are located between the two bearing plates, a first folded edge is arranged on the vertical edge of the sleeve, a second folded edge is arranged on the edge of the bearing plate, and the ends of the first folded edge and the second folded edge are abutted; the welding fixture includes: A base, which is matched with the sleeve and is used for fitting into the sleeve; a first groove is arranged at the side corner of the base close to the first folded edge, and the first groove is used for accommodating the first folded edge and the second folded edge; A clamping plate, which is detachably installed outside the first groove and covers the first groove, and is used for pressing the first folded edge and the second folded edge simultaneously; an opening groove is arranged on the edge of the clamping plate close to the first folded edge, the projection of the abutting position of the first folded edge and the second folded edge on the first groove is a first projection, the projection of the opening groove on the first groove is a second projection, the first projection is located within the second projection, the thickness of the first folded edge is equal to the thickness of the second folded edge, and the depth of the first groove is less than the thickness of the first folded edge; a notch is arranged at the corner of the base close to the core plate bundle, a second groove is arranged at the bottom of the first groove, a ceramic cushion block is fitted in the second groove, and the depth of the second groove is equal to the thickness of the ceramic cushion block; the projection of the second groove on the first groove is a third projection, and the second projection is located within the third projection; A gas supply unit, which is installed on the base and is used for providing a shielding gas to the abutting position of the first folded edge and the second folded edge; the gas supply unit includes: a first channel, which is arranged on the side wall of the base and vertically penetrates the bottom of the second groove; a second channel, which is arranged in the base and vertically penetrates the first channel; a third channel, which is arranged in the base, one end penetrates the side wall of the notch, and the other end penetrates the second channel; an inlet pipe, which is arranged in the notch and is communicated with the port of the third channel for transporting the shielding gas; A cooling unit, which is installed on the base and is used for reducing the temperature of the welding fixture; The first folded edges are arranged on both side edges of the sleeve along the first horizontal direction, the first grooves and the clamping plates are arranged at both side corners of the base along the first horizontal direction; the gas supply units are arranged on both sides of the notch along the first horizontal direction, a tee pipe is connected between the inlet pipes of the two gas supply units, the tee pipe is arranged in the notch, and the branch pipe of the tee pipe is connected to a gas source; a plurality of vertical through holes are arranged at intervals in the base, and the plurality of vertical through holes are axially symmetrically distributed along the second horizontal direction, the second horizontal direction is perpendicular to the first horizontal direction, and the cooling unit includes a cooling pipe, and the cooling pipe sequentially penetrates through the plurality of vertical through holes for providing a coolant.

2. The welding fixture according to claim 1, characterized in that, The clamping plate is connected to the base by bolts, and the ceramic spacer is connected to the base by bolts or adhesively bonded.

3. A heat exchanger welding method, characterized in that using the welding tooling described in any one of claims 1-2, the heat exchanger welding method comprising: fitting the base into the inner end of the sleeve; activating the air supply unit, installing the clamping plate on the base, while pressing the first folded edge and the second folded edge, so that the welding tooling is fixed on the heat exchanger, and the abutting portion of the first folded edge and the second folded edge is exposed through the opening groove; activating the cooling unit to weld the abutting portion of the first folded edge and the second folded edge; closing the air supply unit and the cooling unit, removing the clamping plate, and separating the welding tooling from the heat exchanger.

4. A heat exchanger, characterized in that it is obtained by welding using the heat exchanger welding method described in claim 3.

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