Laser welding protective cover

Abstract

The utility model provides a laser welding protection cover which is applied to heat exchange plate butt welding and comprises a first shell, a second shell and a third shell, the top of the first shell communicates with a vertical first gas inlet pipe, and the first gas inlet pipe is used for preventing gas from entering the first shell and allowing a laser beam to penetrate through the first shell; the side, away from the first air inlet pipe, of the first shell is sleeved with the second shell. The side, close to the first air inlet pipe, of the second shell is connected with the first shell through a spring, so that the second shell reciprocates in the thickness direction, and the moving position is limited; the side, away from the first air inlet pipe, of the second shell is used for abutting against a heat exchange plate pair so that the first shell, the second shell and the heat exchange plate pair can form a closed space. The laser welding protection cover is simple in structure and convenient to use, the welding quality can be effectively improved, and damage to workpieces is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of welding of heat exchange plates, and particularly to a laser welding protective cover. 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, etc. A heat exchanger is usually formed by stacking pairs of heat exchange plates and assembling and welding them with frame members. Titanium plates are widely used in the heat transfer plate pairs made of titanium plates in the petroleum and chemical industries due to their excellent corrosion resistance.

[0003] However, since titanium is relatively active, it begins to absorb hydrogen at about 250°C, begins to absorb oxygen at about 400°C, and begins to absorb nitrogen at 600°C, and air contains a large amount of oxygen and nitrogen. Therefore, in the process of laser welding of heat exchange plate pairs, the gas protection of the welding molten pool is crucial. The existing welding method uses a trailing shield to protect the welding molten pool, but the trailing shield does not fit closely with the heat exchange plate pairs, and there are gaps during the movement of the trailing shield, allowing air to mix into the protective gas and affecting the welding effect. If the pressure on the trailing shield is increased, it is easy to scratch the heat exchange plate pairs. Therefore, there is an urgent need for a protective cover that can improve the welding effect. Summary of the Utility Model

[0004] In view of this, the purpose of the present application is to provide a laser welding protective cover to solve the related problems mentioned in the background art.

[0005] Based on the above purpose, the present application provides a laser welding protective cover for use in welding of heat exchange plate pairs, including: a first housing, with a vertical first air inlet pipe connected to the top, the first air inlet pipe being used for the protective gas to enter the first housing and for the laser beam to pass through the first housing; a second housing, sleeved on the side of the first housing away from the first air inlet pipe; the side of the second housing close to the first air inlet pipe is connected to the first housing by a spring, so that the second housing reciprocates in the thickness direction and the movement position is limited; the side of the second housing away from the first air inlet pipe is used to abut against the heat exchange plate pair, so that a closed space is formed among the first housing, the second housing and the heat exchange plate pair.

[0006] Further, an air extraction pipe is connected to one side of the top of the first housing along the length direction, and the air extraction pipe is used to connect a negative pressure air extraction device.

[0007] Further, the cross-sectional shape of the connection part of the air extraction pipe and the first housing is rectangular, and the rectangle is arranged along the width direction of the first housing.

[0008] Further, at least one second air inlet pipe is provided at the top of the first housing. The second air inlet pipe is located on the side of the first air inlet pipe away from the air extraction pipe and is used for the protective gas to enter the first housing.

[0009] Further, there are a plurality of the second air inlet pipes, and the distance between two adjacent second air inlet pipes is 30 mm to 60 mm.

[0010] Further, the second air inlet pipe is inclined in a direction away from the first air inlet pipe.

[0011] Further, the cross-sectional area of the connection between the first air inlet pipe and the first housing is a first area, the cross-sectional area of the connection between the second air inlet pipe and the first housing is a second area, and the cross-sectional area of the connection between the air extraction pipe and the first housing is a third area. The third area is 0.8 to 1.2 times the sum of the first area and the second area.

[0012] Further, a vertical first screen and a horizontal second screen are provided inside the first housing. The first screen, the second screen and the first housing form a gas distribution space, and the gas distribution space is communicated with the second air inlet pipe.

[0013] Further, a steel wool block is provided in the gas distribution space.

[0014] Further, a top plate is provided at the top of the first housing. The size of the top plate is the same as the cross-sectional size of the second housing. A plurality of the springs are respectively provided on two opposite sides of the top plate along the width direction.

[0015] As can be seen from the above, the laser welding protection cover provided by the present application includes a first housing, a vertical first air inlet pipe communicated at the top. The first air inlet pipe is used for the protective gas to enter the first housing and for the laser beam to pass through the first housing; a second housing sleeved on the side of the first housing away from the first air inlet pipe; one side of the second housing close to the first air inlet pipe is connected to the first housing through a spring, so that the second housing reciprocates in the thickness direction and the moving position is limited; the side of the second housing away from the first air inlet pipe is used to abut against the heat exchange plate pair, so that the first housing, the second housing and the heat exchange plate pair form a closed space to protect the welding molten pool; through the floating design of the first housing and the second housing, it can be adjusted at any time according to the height change of the heat exchange plate pair, so that the second housing is always attached to the heat exchange plate pair, avoiding mixing in air and affecting the welding quality; at the same time, the friction of the floating design is small, avoiding scratching the heat exchange plate pair by the second housing. The laser welding protection cover has a simple structure and is convenient to use, can effectively improve the welding quality and avoid damaging the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic three-dimensional structure diagram of a laser welding protective cover in an embodiment of the present application;

[0018] Figure 2 is Figure 1 a schematic cross-sectional structure diagram of the laser welding protective cover in;

[0019] Figure 3 is Figure 1 a schematic internal structure diagram of the laser welding protective cover in;

[0020] Figure 4 It is a schematic cross-sectional structure diagram of the top plate in an embodiment of the present application.

[0021] Reference numerals: 1, first housing; 1-1, top plate; 2, first intake pipe; 3, second housing; 3-1, spring; 4, exhaust pipe; 5, second intake pipe; 6, first screen; 7, second screen; 8, heat exchange plate pair; 9, steel wool block. Detailed implementation manners

[0022] To make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the following further details the present application in combination with specific embodiments and with reference to the accompanying drawings.

[0023] 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 meaning understood by those of ordinary skill in the art in the field to which this disclosure belongs. The "first", "second", and similar terms used in this disclosure do not indicate 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", "right", etc. are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0024] 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. Heat exchangers are usually formed by stacking heat exchange plate pairs and assembling and welding them with frame parts. Due to its excellent corrosion resistance, titanium plates are widely used in the heat transfer plate pairs made of titanium plates in the petroleum and chemical industries.

[0025] However, since titanium is relatively active, it begins to absorb hydrogen at about 250 °C, begins to absorb oxygen at about 400 °C, and begins to absorb nitrogen at 600 °C. And air contains a large amount of oxygen and nitrogen. Therefore, during the laser welding process of heat exchange plate pairs, the gas protection of the welding molten pool is crucial. Existing welding methods use a trailing shield to protect the welding molten pool. However, the trailing shield does not fit closely enough with the heat exchange plate pairs, and there are gaps during the movement of the trailing shield, allowing air to mix into the shielding gas and affecting the welding effect. If the pressure on the trailing shield is increased, it is easy to scratch the heat exchange plate pairs. Therefore, there is an urgent need for a protective cover that can improve the welding effect.

[0026] In addition, gas protection during the cooling process of the weld seam after welding is also very important. Premature contact with air is likely to cause oxidation and affect the welding quality. Moreover, due to the particularity of laser welding, a large amount of welding fumes are generated during the welding process. Welding fumes not only affect the welding quality but also pollute the environment, and attention should also be paid to the centralized treatment of welding fumes during the welding process.

[0027] Patent CN105728940A discloses a laser welding coaxial gas protection method, which can only protect the molten pool and does not protect the solidified but uncooled weld metal, affecting the weld quality.

[0028] Patent CN105171236B discloses a laser welding single-tube side-blowing gas protection method. When welding an arc-shaped weld seam, the molten pool cannot be fully protected, and at the same time, the solidified but uncooled weld seam is not protected, affecting the weld quality.

[0029] Patent CN107081524A discloses a laser welding side-blowing plus tail-gas blowing protection method. Although this method can protect the weld seam, there is a gap between the protection tooling and the workpiece, and it is extremely easy to let air into the protection gas flow during the rapid laser welding process, resulting in weld oxidation.

[0030] Patent CN203817641U discloses a laser welding overall protection method. Although this method can protect the weld seam, it is necessary to evacuate the air in the protective cover before welding, with low welding efficiency and serious gas waste. At the same time, it is difficult to evacuate the air in the protective cover for large-sized workpieces, and the ion cloud and welding fumes generated by laser welding cannot be discharged in time, polluting the environment and affecting the weld quality.

[0031] The following will further elaborate on the technical solution of the present application in detail through specific embodiments in combination with the attached drawings. Figures 1 to 4 The technical solution of the present application will be further described in detail.

[0032] In some embodiments of the present application, a laser welding protective cover is provided, which is applied to the welding of heat exchange plate pairs 8. As Figure 1 and Figure 2 shown, it includes: a first housing 1, with a vertical first intake pipe 2 connected to the top. The first intake pipe 2 is used for the protective gas to enter the first housing 1 and for the laser beam to pass through the first housing 1; a second housing 3, sleeved on the side of the first housing 1 away from the first intake pipe 2; the side of the second housing 3 close to the first intake pipe 2 is connected to the first housing 1 through a spring 3-1, so that the second housing 3 reciprocates in the thickness direction and the moving position is restricted; the side of the second housing 3 away from the first intake pipe 2 is used to abut against the heat exchange plate pair 8, so that a sealed space is formed among the first housing 1, the second housing 3 and the heat exchange plate pair 8.

[0033] As Figure 1 shown, in the figure, the L direction is the length direction and the W direction is the width direction. The laser welding protective cover includes a first housing 1. The first housing 1 is, for example, in the shape of a cuboid, and a vertical first intake pipe 2 is connected to the top. The first intake pipe 2 can be integrally formed with the first housing 1. The first intake pipe 2 can be connected to an air intake device for the protective gas to enter the first housing 1. The first intake pipe 2 can also wrap the laser welding gun for the laser beam to pass through the first housing 1 to weld the heat exchange plate pair 8.

[0034] As Figure 2 shown, the second housing 3 is sleeved on the side of the first housing 1 away from the first intake pipe 2. The second housing 3 is, for example, in the shape of a cuboid. The side of the second housing 3 close to the first intake pipe 2 is connected to the first housing 1 through a spring 3-1, so that the second housing 3 reciprocates in the thickness direction, and the moving position of the second housing 3 is restricted by the expansion and contraction of the spring 3-1; the side of the second housing 3 away from the first intake pipe 2 is used to abut against the heat exchange plate pair 8, so that a sealed space is formed among the first housing 1, the second housing 3 and the heat exchange plate pair 8 to protect the welding molten pool; through the floating design of the first housing 1 and the second housing 3, it can be adjusted at any time according to the height change of the heat exchange plate pair 8, so that the second housing 3 always fits the heat exchange plate pair 8, avoiding the mixing of air and affecting the welding quality; at the same time, the floating design has a small friction force, avoiding scratching the heat exchange plate pair 8 by the second housing 3.

[0035] The first housing 1 and the second housing 3 can be made of metal or high-temperature resistant plastic. Through the floating design, it is ensured that the protective cover is always in full contact with the workpiece during the welding process, which can not only avoid the problem of poor protection caused by the deformation of the workpiece during the welding process, but also solve the problem that air is easily mixed into the protective gas due to rapid welding; the laser welding protective cover has a simple structure and is convenient to use, which can effectively improve the welding quality and avoid damaging the workpiece.

[0036] In some embodiments, such as Figure 1 and Figure 2 shown, one side of the top of the first housing 1 along the length direction is communicated with an exhaust pipe 4, and the exhaust pipe 4 is used to connect a negative pressure exhaust device.

[0037] As Figure 1 shown, the first housing 1 is also communicated with an exhaust pipe 4, which is located in front of the first intake pipe 2. The exhaust pipe 4 can be integrally formed with the first housing 1; during laser welding, a large amount of soot and ion clouds will appear. The soot and ion clouds will shield the laser, resulting in a decrease in welding energy and a deterioration in the quality of the weld seam. At the same time, the soot is harmful to the human body, pollutes the environment when discharged into the air, and endangers the physical health of personnel. The exhaust pipe 4 can be connected to a negative pressure exhaust device to timely exhaust the soot and ion clouds at the welding position, reduce the shielding effect on the laser, improve the welding quality, and at the same time collect the welding soot to reduce environmental pollution.

[0038] In some embodiments, such as Figure 4 shown, the cross-sectional shape of the connection between the exhaust pipe 4 and the first housing 1 is rectangular, and the rectangle is arranged along the width direction of the first housing 1.

[0039] As Figure 4 shown, the cross-sectional shape of the connection between the exhaust pipe 4 and the first housing 1 is rectangular, and the rectangle is arranged along the width direction of the first housing 1. On the one hand, it not only reduces the dead zone during the exhaust process, but also can suck out the harmful gases near the edge of the housing. On the other hand, the exhaust pipe 4 and the first intake pipe 2 form a radially expanding shape from narrow to wide, ensuring that the laser welding core and the heat affected zone can be effectively protected by the gas.

[0040] In some embodiments, such as Figure 1 and Figure 2 shown, at least one second intake pipe 5 is provided on the top of the first housing 1, and the second intake pipe 5 is located on the side of the first intake pipe 2 away from the exhaust pipe 4 for the protective gas to enter the first housing 1.

[0041] As Figure 2As shown, a second intake pipe 5 is also provided at the top of the first housing 1. The second intake pipe 5 is located behind the first intake pipe 2 and can be connected to an intake device. In this way, after a weld seam is formed at the front first intake pipe 2, as the protective cover moves forward, the unfrozen and cooled weld seam can be at the position of the second intake pipe 5, so that the weld seam is always in an atmosphere of protective gas, ensuring the welding quality. The cross-sectional shapes of the first intake pipe 2 and the second intake pipe 5 are, for example, circular, and no specific limitation is made.

[0042] In some embodiments, as Figure 1 and Figure 2 shown, there are multiple second intake pipes 5, and the distance between two adjacent second intake pipes 5 is 30 mm to 60 mm.

[0043] As Figure 2 shown, two second intake pipes 5 are provided to ensure the gas concentration in the protective cover to ensure the weld quality. The distance between two adjacent second intake pipes 5 is 30 mm to 60 mm, for example, 45 mm, etc., and no specific limitation is made to ensure uniform distribution of the gas in the protective cover.

[0044] In some embodiments, as Figure 1 and Figure 2 shown, the second intake pipe 5 is inclined in a direction away from the first intake pipe 2.

[0045] As Figure 2 shown, the second intake pipe 5 is inclined backward so that the protective gas can move forward along the second intake pipe 5, accelerating the cooling of the weld seam and also ensuring rapid filling of the protective cover with gas.

[0046] In some embodiments, as Figure 4 shown, the cross-sectional area of the connection between the first intake pipe 2 and the first housing 1 is a first area, the cross-sectional area of the connection between the second intake pipe 5 and the first housing 1 is a second area, and the cross-sectional area of the connection between the exhaust pipe 4 and the first housing 1 is a third area. The third area is 0.8 to 1.2 times the sum of the first area and the second area.

[0047] As Figure 4 shown, the third area can be approximately equal to the sum of the first area and the second area. In this way, it can ensure that the inside of the protective cover is all protective gas, ensure stable gas flow rate, and at the same time, the same gas inflow and outflow can also ensure that welding fumes do not escape into the air and oxygen in the air does not enter the protective cover, improving the weld protection effect.

[0048] In some embodiments, as Figure 2 and Figure 3As shown, a vertical first screen 6 and a horizontal second screen 7 are provided inside the first housing 1. The first screen 6, the second screen 7 and the first housing 1 form a gas distribution space, and the gas distribution space is communicated with the second intake pipe 5.

[0049] As Figure 4 shown, a connected first screen 6 and second screen 7 are provided inside the first housing 1. The gas from the second intake pipe 5 can be evenly distributed through the screens, so that the protective gas uniformly fills the protective cover. In this way, the welding protection effect can reach the best even when the gas flow rate is very small, which not only saves gas but also ensures the weld quality.

[0050] In some embodiments, as Figure 2 shown, a steel wool block 9 is provided inside the gas distribution space.

[0051] As Figure 2 shown, a steel wool block 9 is filled between the screen and the first housing 1, which can further evenly distribute the protective gas.

[0052] In some embodiments, as Figure 1 and Figure 3 shown, a top plate 1-1 is provided at the top of the first housing 1. The size of the top plate 1-1 is the same as the cross-sectional size of the second housing 3. A plurality of the springs 3-1 are respectively provided on opposite sides of the top plate 1-1 along the width direction.

[0053] As Figure 1 shown, a top plate 1-1 is provided at the top of the first housing 1. The cross-sectional size of the top plate 1-1 is the same as that of the second housing 3, which can play a limiting role and facilitate the connection of the springs 3-1. As Figure 3 shown, three evenly distributed springs 3-1 are provided on the long side of the top plate 1-1, which can ensure the connection stability between the first housing 1 and the second housing 3.

[0054] The overall laser welding protective cover enables the laser beam to be completely in the protective gas atmosphere for welding, solving the protection problems of different forms of welds, such as arc welds, curved welds, circular welds, etc.; the addition of screens and steel wool blocks 9 inside the first housing 1 makes the distribution of the protective gas more uniform and the weld protection effect better; the springs 3-1 enable the housing to have an up-and-down floating function, enabling the second housing 3 to always be in full contact with the workpiece, solving the problem that air is easily mixed in during the welding process, and at the same time avoiding the situation that the protective cover scratches the workpiece during the welding process; by adding the exhaust pipe 4, the shielding effect of the ion cloud on the laser is solved, the weld quality is improved, and at the same time the welding fumes are collected for centralized treatment, avoiding environmental pollution and reducing the harm of welding fumes to the human body.

[0055] Those of ordinary skill in the art should understand that any discussion of the above embodiments is exemplary only and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the concept of this 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 present application as described above, which are not provided in detail for the sake of brevity.

[0056] 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 principles of the present application shall be included within the protection scope of the present application.

Claims

1. A laser welding protective cover, characterized in that, Applied to the welding of heat exchange plate pairs, including: A first housing, with a vertical first inlet pipe connected to its top. The first inlet pipe is used for the protective gas to enter the first housing and for the laser beam to pass through the first housing. A second housing, sleeved on one side of the first housing away from the first inlet pipe. One side of the second housing close to the first inlet pipe is connected to the first housing by a spring, so that the second housing can reciprocate in the thickness direction and the moving position is restricted. The side of the second housing away from the first inlet pipe is used to abut against the heat exchange plate pair, so that a closed space is formed by the first housing, the second housing and the heat exchange plate pair.

2. The laser welding protective cover according to claim 1, wherein, One side of the top of the first housing along the length direction is connected with an exhaust pipe, and the exhaust pipe is used to connect a negative pressure exhaust device.

3. The laser welding protective cover according to claim 2, characterized in that, The cross-sectional shape of the connection between the exhaust pipe and the first housing is rectangular, and the rectangle is arranged along the width direction of the first housing.

4. The laser welding protective cover according to claim 2, wherein, At least one second inlet pipe is provided on the top of the first housing. The second inlet pipe is located on the side of the first inlet pipe away from the exhaust pipe and is used for the protective gas to enter the first housing.

5. The laser welding protective cover according to claim 4, characterized in that There are multiple second inlet pipes, and the distance between adjacent two second inlet pipes is 30 mm to 60 mm.

6. The laser welding protective cover according to claim 4, characterized in that, The second inlet pipe is inclined in the direction away from the first inlet pipe.

7. The laser welding protective cover according to claim 4, characterized in that, The cross-sectional area of the connection between the first inlet pipe and the first housing is the first area, the cross-sectional area of the connection between the second inlet pipe and the first housing is the second area, and the cross-sectional area of the connection between the exhaust pipe and the first housing is the third area. The third area is 0.8 to z times the sum of the first area and the second area.

8. The laser welding protective cover according to claim 4, characterized in that, A vertical first screen and a horizontal second screen are provided in the first housing. The first screen, the second screen and the first housing form a gas distribution space, and the gas distribution space is communicated with the second inlet pipe.

9. The laser welding protective cover according to claim 8, wherein, A steel wool block is provided in the gas distribution space.

10. The laser welding protective cover according to claim 1, wherein, A top plate is provided on the top of the first housing. The size of the top plate is the same as the cross-sectional size of the second housing, and multiple springs are respectively provided on the two opposite sides of the top plate along the width direction. Note: In the original text, the value range of the multiple in is incorrect. It should be 1.2 times instead of "z times". The above translation has been corrected accordingly.

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