Umbrella-shaped micro-jet laser water return prevention device

Abstract

The invention discloses an umbrella-shaped micro-jet laser water-return-preventing device, and particularly relates to the field of micro-jet laser processing, the umbrella-shaped micro-jet laser water-return-preventing device comprises a nozzle and a water-return-preventing mechanism, the water-return-preventing mechanism comprises a mounting seat mounted at the bottom of the nozzle, and the mounting seat and the nozzle are coaxially mounted; the water return prevention mechanism comprises a mounting seat and a water return prevention assembly, the water return prevention assembly comprises an inner umbrella and an outer umbrella which are coaxially nested, the inner umbrella is located on the inner side of the outer umbrella, a through hole for the laser beam and the main water jet flow to pass through is formed in the center of the inner umbrella, and the through hole is located in the coaxial radial position between the inner umbrella and the nozzle. By means of the double-umbrella-shaped structure composed of the inner umbrella and the outer umbrella, by intercepting discrete liquid drops and inhibiting diffusion of water mist, the problem that the nozzle is burnt down due to the fact that splashing return water is gathered at the micro-jet guide nozzle can be solved, and therefore the water jet machining effect can be guaranteed, and the machining quality of the water jet can be guaranteed.

Description

A type of umbrella-shaped micro-jet laser anti-backflow device Technical Field

[0001] This invention relates to the field of microjet laser processing technology, and more specifically, to an umbrella-shaped microjet laser anti-backflow device. Background Technology

[0002] Microjets laser technology is an advanced technique that couples a high-energy laser beam into a micrometer-scale high-pressure water jet, using the principle of total internal reflection at the water-air interface to guide the laser for processing. This technology perfectly combines the high energy density of lasers with the cooling, cleaning, and light-guiding properties of water jets, enabling high-quality, low-damage processing of hard, brittle, and heat-sensitive materials, giving it irreplaceable advantages in aerospace, semiconductor, and other fields.

[0003] When a high-pressure water jet impacts the workpiece surface, it inevitably splashes outwards, creating backflow. These splashed water droplets or vapors accumulate and condense at the bottom of the expensive sapphire or diamond nozzle and near the micro-jet guide nozzle. These adhering water droplets drip intermittently or continuously, disrupting the laminar flow of the stable water jet below and directly affecting processing accuracy. In more severe cases, the accumulated water droplets can be heated by the laser energy, causing the nozzle to be instantly destroyed. Replacing the nozzle is not only costly but also requires complex recalibration, severely impacting processing efficiency and equipment reliability.

[0004] To address the issue of water backflow, existing technologies primarily employ two technical solutions;

[0005] Coaxial auxiliary gas protection: Its principle is pneumatic purging, using a coaxial or inclined compressed air ring to form an air curtain around the jet, dispersing back water and water mist. This increases the energy consumption of compressed air, but it can effectively disperse some splashes and mist, and helps to stabilize the water jet.

[0006] High-speed rotating ejector disc: Its principle is centrifugal force ejection. A high-speed motor-driven rotating disc is installed below the nozzle, using centrifugal force to eject the splashing water. It provides active protection and has a high efficiency in removing splashed droplets.

[0007] However, using coaxial auxiliary gas protection cannot completely block all backflow, especially water film already attached to a fixed surface. It requires an additional high-pressure gas source, increasing system complexity and energy consumption. While the airflow disperses the backflow, it may interfere with the stability of the precision microjet. Using a high-speed rotating ejector plate requires the introduction of a high-speed rotating seal and motor, resulting in a complex structure, high reliability risk, susceptibility to vibration, high noise, inconvenient maintenance, and difficulty in preventing water mist from condensing on the rotating parts. It still cannot remove backflow at small angles. The rotating mechanism causes additional airflow, affecting the stability of the microjet. Summary of the Invention

[0008] This invention provides an umbrella-shaped microjets laser anti-backflow device to solve the problem that when a high-pressure water jet impacts the workpiece surface, it inevitably splashes outwards, forming splash water. The splashed water droplets or vapor accumulate and condense at the bottom of expensive sapphire or diamond nozzles and near the microjets' guide nozzles. These attached water droplets drip intermittently or continuously, interfering with the laminar flow of the stable water jet below, directly affecting processing accuracy. In more severe cases, the accumulated water droplets can be heated by the laser energy, causing the nozzle to be instantly destroyed.

[0009] To achieve the above objectives, the present invention provides the following technical solution: an umbrella-shaped micro-jet laser anti-backflow device, comprising a nozzle and an anti-backflow mechanism, wherein the anti-backflow mechanism includes a mounting base installed at the bottom of the nozzle, and the mounting base is coaxially installed with the nozzle;

[0010] The anti-backflow mechanism includes a mounting base and an anti-backflow component. The anti-backflow component includes an inner umbrella and an outer umbrella that are coaxially nested. The inner umbrella is located inside the outer umbrella. The center of the inner umbrella has a through hole for the laser beam and the main water jet to pass through. The through hole is located in the coaxial radial position between the inner umbrella and the nozzle.

[0011] The inner umbrella is used to collect and guide the return water and water vapor in a small area near the jet, as well as to block the return water and water vapor reflected by the outer umbrella from entering the jet area. The outer umbrella is used to collect most of the return water and water vapor outside the range of the inner umbrella, and to guide the water droplets condensed on the lower surface of the outer umbrella to flow out along the edge of the outer umbrella.

[0012] In a preferred embodiment, the outer umbrella includes a plurality of umbrella blade units that are equally spaced along the circumference of the mounting base. The plurality of umbrella blade units are hinged to the mounting base. The mounting base is provided with a tilt adjustment mechanism, which drives the plurality of umbrella blade units to swing synchronously to adjust the tilt angle of the outer umbrella.

[0013] In a preferred embodiment, the tilt adjustment mechanism further includes a sliding frame slidably connected to the mounting base and a fixing block fixedly mounted on the mounting base. A limit frame is fixedly mounted on the mounting base, and the sliding frame is slidably mounted on the limit frame. The umbrella unit is hinged to the fixing block, and multiple hinge rods are hinged to the umbrella unit. All the hinge rods are hinged to the sliding frame. The tilt adjustment mechanism causes the hinge rods to swing the multiple umbrella units by sliding the sliding frame, thereby driving the outer umbrella to change its tilt angle.

[0014] In a preferred embodiment, the tilt adjustment mechanism further includes an elastic element disposed between two adjacent umbrella blade units, which is used to compensate for the gap between the two adjacent umbrella blade units when the tilt angle of the outer umbrella changes.

[0015] In a preferred embodiment, the edge of the outer umbrella is further provided with an edge extension mechanism, which is used to expand the effective protective area of ​​the outer umbrella during operation.

[0016] In a preferred embodiment, the edge extension mechanism includes a side plate slidably disposed on the edge of the inner umbrella, a telescopic component disposed on the side plate, and a guide plate fixedly disposed on the mounting base. The side plate and the guide plate are in movable contact. The edge extension mechanism is used to extend or retract the side plate at the edge of the outer umbrella through the movable contact between the side plate and the guide plate when the tilt adjustment mechanism adjusts the tilt angle of the inner umbrella, so as to expand or shrink the protective area of ​​the outer umbrella.

[0017] In a preferred embodiment, the edge extension mechanism further includes an elastic element two disposed between the side panel and the outer umbrella. When the edge extension mechanism is extended, the elastic element two is extended, and the extended portion constitutes an additional extended protective area of ​​the outer umbrella. When the edge extension mechanism is retracted, the elastic element two retracts and resets, and the extended protective area retracts and resets.

[0018] In a preferred embodiment, the telescopic assembly includes a sliding rod, and an inner cavity is provided in the umbrella unit for the sliding rod to slide in. The sliding rod is slidably disposed in the inner cavity. The telescopic assembly also includes an elastic element three disposed in the inner cavity, which is used to provide elastic reset for the sliding rod to slide.

[0019] In a preferred embodiment, the second elastic element and the first elastic element are integrally formed, and the whole is in the shape of an umbrella ring structure. The whole is installed between multiple umbrella blade units and multiple side plates. The umbrella ring structure includes the first elastic element for compensating for the tilt angle adjustment gap and the second elastic element for realizing edge elastic expansion and reset.

[0020] In a preferred embodiment, the inner umbrella is fixedly connected to the mounting base to form a fixed primary flow guiding structure.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention, through a double umbrella-shaped structure consisting of an inner umbrella and an outer umbrella, intercepts discrete droplets and suppresses the diffusion of water mist. It also avoids the problem of nozzle burnout caused by splashing water accumulating at the microjet guide nozzle, thereby ensuring the processing effect and quality of the water jet.

[0023] This invention, by setting up an angle adjustment mechanism, can continuously guide the return water flow by changing the angle of the outer umbrella when processing large curved workpieces. Attached Figure Description

[0024] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0025] Figure 2 is a cross-sectional view of the three-dimensional structure of the present invention;

[0026] Figure 3 is a three-dimensional structural schematic diagram of the tilt adjustment mechanism of the present invention;

[0027] Figure 4 is a schematic diagram of the front cross-sectional structure of the tilt adjustment mechanism of the present invention;

[0028] Figure 5 is a schematic diagram of the tilt adjustment mechanism of the present invention after adjustment.

[0029] Figure 6 is a three-dimensional schematic diagram of the edge extension mechanism of the present invention;

[0030] Figure 7 is a schematic diagram of the front cross-sectional structure of the edge extension mechanism of the present invention;

[0031] Figure 8 is a three-dimensional schematic diagram of the edge extension mechanism of the present invention after adjustment;

[0032] Figure 9 is a schematic diagram of the edge extension mechanism of the present invention after adjustment.

[0033] Figure 10 is an enlarged schematic diagram of part of the structure in Figure 9.

[0034] The attached figures are labeled as follows: 1. Nozzle; 2. Anti-backflow mechanism; 21. Mounting base; 22. Anti-backflow assembly; 221. Inner umbrella; 2211. Through hole; 222. Outer umbrella; 2221. Umbrella fin unit; 3. Tilt adjustment mechanism; 31. Sliding frame; 32. Limiting frame; 33. Hinge rod; 34. Elastic element one; 35. Fixing block; 4. Edge extension mechanism; 41. Elastic element two; 42. Side plate; 43. Telescopic assembly; 431. Sliding rod; 432. Inner cavity; 433. Elastic element three; 44. Guide plate. Detailed Implementation

[0035] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0036] Referring to Figures 1 and 2 in the specification, an umbrella-shaped micro-jet laser anti-backflow device includes a nozzle 1 and an anti-backflow mechanism 2. The anti-backflow mechanism 2 includes a mounting base 21 installed at the bottom of the nozzle 1, and the mounting base 21 is coaxially installed with the nozzle 1.

[0037] The anti-backflow mechanism 2 includes a mounting base 21 and an anti-backflow component 22. The anti-backflow component 22 includes an inner umbrella 221 and an outer umbrella 222 that are coaxially nested. The inner umbrella 221 is located inside the outer umbrella 222. The center of the inner umbrella 221 is provided with a through hole 2211 for the laser beam and the main water jet to pass through. The through hole 2211 is located in a coaxial radial position between the inner umbrella 221 and the nozzle 1.

[0038] The inner umbrella 221 is used to collect and guide the return water and water vapor in a small area near the jet, and to block the return water and water vapor reflected by the outer umbrella 222 from entering the jet area. The outer umbrella 222 is used to collect most of the return water and water vapor outside the range of the inner umbrella 221, and to guide the water droplets condensed on the lower surface of the outer umbrella 222 to flow out along the edge of the outer umbrella 222.

[0039] It should be noted that the anti-backflow mechanism 2 is coaxially fixed to the bottom of the nozzle 1 by a mounting base 21, so that it can ensure that it coincides with the axis of the laser and the main water jet, ensuring the stable operation of laser cutting. The anti-backflow component 22 forms a double umbrella-shaped structure through the inner umbrella 221 and the outer umbrella 222. The inner umbrella 221 is nested inside the outer umbrella 222, and the two are coaxially set. The center of the inner umbrella 221 has a through hole 2211, which provides an unobstructed channel for the laser beam and the main processing water jet. The inner umbrella 221 is responsible for blocking and initially guiding the core backflow with the highest energy that is directly reflected back from the surface of the workpiece, deflecting it and preventing it from directly impacting the nozzle 1 body. The outer umbrella 222 is used to intercept the discrete droplets that escape from around the inner umbrella 221 and the splashes from the outer periphery, expanding the overall protection range.

[0040] It should also be noted that the inner umbrella 221 and the outer umbrella 222 are coated with a special coating (superhydrophobic coating) to ensure that water splashed onto the umbrella surface can quickly escape and cannot stay and accumulate.

[0041] The specific implementation scenario is as follows: During use, by installing an anti-backflow mechanism 2 at the bottom of nozzle 1, during laser cutting, a high-pressure water jet is ejected from the center of nozzle 1, vertically impacting the workpiece surface for cutting. Simultaneously, high-temperature, high-speed backflow splashes are generated. At this time, the high-speed core reflection stream first impacts the inclined umbrella surface of the inner umbrella 221. Because the inner umbrella 221 has a through hole 2211 at its center for the laser and water jet to pass through, its umbrella surface is located precisely on the main path of the core splash. When the high-speed droplets impact the umbrella surface, the droplets will change from radial splashing to axial or oblique sliding along the umbrella surface, thus preventing the core droplets, which pose the greatest threat to nozzle 1, from directly and head-on impacting nozzle 1. The outer umbrella 222 protects the nozzle 1 above. At the same time, the outer umbrella 222 is located below the outer periphery of the inner umbrella 221 and has a larger diameter. It can intercept discrete droplets splashed from the protective range of the inner umbrella 221. The outer umbrella 222 further guides the guiding liquid from the inner umbrella 221 and the droplets intercepted by itself, so that the liquid can gradually flow along the outer umbrella 222 to the edge of the outer umbrella 222. This can ensure the processing effect of the water jet and avoid the problem of nozzle 1 burning due to splashing back water accumulation. In addition, the presence of the outer umbrella 222 can also form a barrier for the rising water mist, increasing the probability of water mist colliding and condensing with the solid surface, thereby suppressing the problem of water mist spreading to the more critical area above.

[0042] In the above technical solution, by setting up a double umbrella-shaped mechanism consisting of an inner umbrella 221 and an outer umbrella 222, the water jet can prevent backflow during the microjet laser cutting process. However, when performing microjet laser cutting or surface treatment on large curved workpieces, since the local surface geometry at each point on the processing path is different, the splash direction of the water jet after hitting the workpiece surface is like light reflecting off a mirror. When processing curved surfaces, the tilt angle of each point on the surface is constantly changing, which causes the direction of the reflected splash water column to change continuously. For example, on an outwardly convex curved surface, water droplets will spread more widely, like an explosion from a sphere; while on an inwardly concave curved surface, water droplets may converge and spray out like colliding in a bowl, with unpredictable direction. In this case, the high-speed core splash stream may easily miss the inner umbrella 221 and outer umbrella 222, directly spraying onto the nozzle 1 and causing damage. To address this, the present invention proposes an angle adjustment mechanism 3, which, during the micro-jet laser cutting process, changes the angle of the outer umbrella 222 to achieve precise and continuous guidance of the return water flow. Specifically, referring to Figures 3 to 5 of the specification, the outer umbrella 222 includes multiple umbrella blade units 2221 evenly spaced along the circumference of the mounting base 21. The multiple umbrella blade units 2221 are all hinged on the mounting base 21, and the mounting base 21 is provided with an angle adjustment mechanism 3. The angle adjustment mechanism 3 drives multiple umbrella blade units 2221 to adjust the water flow. The umbrella blade units 2221 swing synchronously to adjust the tilt angle of the outer umbrella 222. The tilt angle adjustment mechanism 3 also includes a sliding frame 31 slidably connected to the mounting base 21 and a fixing block 35 fixedly mounted on the mounting base 21. A limit frame 32 is fixedly mounted on the mounting base 21, and the sliding frame 31 is slidably mounted on the limit frame 32. The umbrella blade units 2221 are hinged to the fixing block 35. Multiple hinge rods 33 are hinged to the umbrella blade units 2221, and all the hinge rods 33 are hinged to the sliding frame 31. The tilt angle adjustment mechanism 3 causes the hinge rods 33 to drive the multiple umbrella blade units 2221 to swing through the sliding frame 31, thereby driving the outer umbrella 222 to change its tilt angle. The tilt angle adjustment mechanism 3 also includes an elastic element 34 disposed between two adjacent umbrella blade units 2221. The elastic element 34 is used to compensate for the gap between two adjacent umbrella blade units 2221 when the outer umbrella 222 changes its tilt angle.

[0043] It should be noted that the sliding frame 31 can be driven to slide by a cylinder, and the elastic element 34 can be made of high-strength, high-temperature resistant, and highly elastic rubber or silicone film. During the micro-jet laser cutting process, the sliding frame 31 can be driven to slide vertically on the limit frame 32 by a cylinder. During the sliding process, the sliding frame 31 can drive the hinge rod 33 to move, and the hinge rod 33 can drive multiple hinged umbrella units 2221 to swing, so that the umbrella surface of the outer umbrella 222 can face the splash direction, achieving the effect of precise and continuous guidance of the backflow.

[0044] It should also be noted that by setting up sensors (such as vision systems or angle sensors) to perceive the curvature changes of the processing points in real time, and dynamically adjusting the tilt angle of the outer umbrella 222 based on the information transmitted by the sensors, the core return water flow can be accurately and continuously guided, thereby effectively solving the dynamic protection problem in curved surface processing.

[0045] In the above technical solution, the problem of backflow prevention in large curved workpieces is solved by setting the tilt angle adjustment mechanism 3. However, when processing long strip metal plates with significant thickness variations but overall straightness during continuous cutting, due to the long length of the workpiece, the temperature near the workpiece cut gradually increases with temperature accumulation in the latter half of the cutting process. At this time, the low-temperature water jet impacts the high-temperature metal surface, and the backflow will turn into easily diffused high-temperature steam and water mist. At this time, the high-temperature steam and fine droplets will bypass the edge of the outer umbrella 222 and rise, causing these steam to condense into water film or water droplets on the surface of the cooler equipment parts, affecting the service life of the equipment. To this end, the present invention also proposes an edge extension mechanism 4, which can extend and expand the edge of the outer umbrella 222 while adjusting the tilt angle of the outer umbrella 222. Specifically, referring to Figures 6 to 10 of the specification, the edge of the outer umbrella 222 is also provided with an edge extension mechanism 4. The edge extension mechanism 4 is used to expand the effective protection area of ​​the outer umbrella 222 during operation. The edge extension mechanism 4 includes a sliding arrangement on the edge of the inner umbrella 221. The outer umbrella 222 has a side plate 42, a telescopic component 43 mounted on the side plate 42, and a guide plate 44 fixedly mounted on the mounting base 21. The side plate 42 and the guide plate 44 are in movable contact. The edge extension mechanism 4 is used to extend or retract the side plate 42 at the edge of the outer umbrella 222 through the movable contact between the side plate 42 and the guide plate 44 when the tilt angle adjustment mechanism 3 adjusts the inner umbrella 221, so as to expand or shrink the protective area of ​​the outer umbrella 222. The edge extension mechanism 4 also includes an elastic element 41 disposed between the side plate 42 and the outer umbrella 222. When opened, the second elastic element 41 is unfolded, and the stretched and unfolded part constitutes an additional extended protective area of ​​the outer umbrella 222. When the edge extension mechanism 4 retracts, the second elastic element 41 retracts and resets, and the extended protective area retracts and resets. The telescopic assembly 43 includes a sliding rod 431. An inner cavity 432 for sliding the sliding rod 431 is opened in the umbrella unit 2221. The sliding rod 431 is slidably disposed in the inner cavity 432. The telescopic assembly 43 also includes a third elastic element 433 disposed in the inner cavity 432. The third elastic element 433 is used to provide elastic reset for the sliding of the sliding rod 431.

[0046] It should be noted that the elastic element 3 433 is a spring, and the elastic element 2 41 can be made of high-strength, high-temperature resistant, and highly elastic rubber or silicone film. When the tilt angle of the outer umbrella 222 is adjusted by the tilt adjustment mechanism 3, the side plate 42 and the guide plate 44 are in contact, so that the elastic deformation of the spring can cause multiple side plates 42 to move radially in a direction away from the mounting base 21. During the synchronous movement of multiple side plates 42, the elastic element 2 41 can be stretched, so that the protective area can be expanded by stretching the elastic element 2 41.

[0047] Furthermore, the second elastic element 41 and the first elastic element 34 are integrally formed structures, and the whole structure is an umbrella-shaped ring structure. The whole structure is installed between multiple umbrella blade units 2221 and multiple side plates 42. The umbrella-shaped ring structure includes the first elastic element 34 for compensating for the tilt angle adjustment gap and the second elastic element 41 for realizing edge elastic expansion and reset.

[0048] It should be noted that by setting the second elastic element 41 and the first elastic element 34 as an integrally formed structure, mounting grooves can be opened on the sides of multiple umbrella units 2221, and they can be installed in the mounting grooves and connected with the corresponding side plates 42 for installation, which facilitates actual use and setup.

[0049] Furthermore, referring to Figure 1 in the instruction manual, the inner umbrella 221 is fixedly connected to the mounting base 21 to form a fixed primary flow guiding structure.

[0050] It should be noted that the inner umbrella 221 is fixedly connected to the mounting base 21 or directly integrally formed. This makes the inner umbrella 221 a fixed and stable primary flow guiding structure, which can reliably and consistently block and divert the strongest backflow from directly below the nozzle 1, establishing a stable protection benchmark for the entire anti-backflow system. Fixing the inner umbrella 221 also provides a reliable spatial reference benchmark for the dynamic adjustment of the outer umbrella 222, making the tilt adjustment and edge expansion action of the outer umbrella 222 more precise and controllable.

[0051] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A type of umbrella-shaped micro-jet laser anti-backflow water device, characterized in that, The device includes a nozzle (1) and an anti-backflow mechanism (2). The anti-backflow mechanism (2) includes a mounting base (21) installed at the bottom of the nozzle (1), and the mounting base (21) is coaxially installed with the nozzle (1). The anti-backflow mechanism (2) includes a mounting base (21) and an anti-backflow assembly (22). The anti-backflow assembly (22) includes an inner umbrella (221) and an outer umbrella (222) coaxially nested. The inner umbrella (221) is located inside the outer umbrella (222), and the center of the inner umbrella (221) is provided with a laser beam and main water supply. The jet passes through a through hole (2211), which is located in a coaxial radial position between the inner umbrella (221) and the nozzle (1); the inner umbrella (221) is used to collect and guide the return water and water vapor in a small area near the jet, and to block the return water and water vapor reflected by the outer umbrella (222) from entering the jet area; the outer umbrella (222) is used to collect most of the return water and water vapor outside the range of the inner umbrella (221), and to guide the water droplets condensed on the lower surface of the outer umbrella (222) to flow out along the edge of the outer umbrella (222).

2. The umbrella-shaped microjets laser anti-backflow device according to claim 1, characterized in that: The outer umbrella (222) includes multiple umbrella blade units (2221) that are equally spaced along the circumference of the mounting base (21). The multiple umbrella blade units (2221) are all hinged on the mounting base (21). The mounting base (21) is provided with a tilt angle adjustment mechanism (3). The tilt angle adjustment mechanism (3) drives the multiple umbrella blade units (2221) to swing synchronously to adjust the tilt angle of the outer umbrella (222).

3. The umbrella-shaped microjets laser anti-backflow device according to claim 2, characterized in that: The tilt adjustment mechanism (3) further includes a sliding frame (31) slidably connected to the mounting base (21) and a fixing block (35) fixedly mounted on the mounting base (21). A limit frame (32) is fixedly mounted on the mounting base (21). The sliding frame (31) is slidably mounted on the limit frame (32). The umbrella unit (2221) is hinged to the fixing block (35). Multiple hinge rods (33) are hinged on the umbrella unit (2221). The multiple hinge rods (33) are all hinged on the sliding frame (31). The tilt adjustment mechanism (3) causes the hinge rods (33) to drive the multiple umbrella units (2221) to swing through the sliding of the sliding frame (31), thereby driving the outer umbrella (222) to change its tilt angle.

4. The umbrella-shaped microjets laser anti-backflow device according to claim 3, characterized in that: The tilt adjustment mechanism (3) further includes an elastic element (34) disposed between two adjacent umbrella blade units (2221), the elastic element (34) being used to compensate for the gap between the two adjacent umbrella blade units (2221) when the outer umbrella (222) changes its tilt angle.

5. The umbrella-shaped microjets laser anti-backflow device according to claim 4, characterized in that: The outer umbrella (222) is also provided with an edge extension mechanism (4) at its edge, which is used to expand the effective protective area of ​​the outer umbrella (222) during operation.

6. The umbrella-shaped microjets laser anti-backflow device according to claim 5, characterized in that: The edge extension mechanism (4) includes a side plate (42) slidably disposed on the edge of the inner umbrella (221), a telescopic component (43) disposed on the side plate (42), and a guide plate (44) fixedly disposed on the mounting base (21). The side plate (42) and the guide plate (44) are in active contact. The edge extension mechanism (4) is used to extend or retract the side plate (42) at the edge of the outer umbrella (222) through the active contact between the side plate (42) and the guide plate (44) when the tilt angle adjustment mechanism (3) adjusts the tilt angle of the inner umbrella (221), so as to realize the expansion and reduction of the protective area of ​​the outer umbrella (222).

7. The umbrella-shaped microjets laser anti-backflow device according to claim 6, characterized in that: The edge extension mechanism (4) also includes an elastic element two (41) disposed between the side plate (42) and the outer umbrella (222). When the edge extension mechanism (4) is deployed, the elastic element two (41) is deployed, and the stretched and deployed part constitutes an additional extended protection area of ​​the outer umbrella (222). When the edge extension mechanism (4) is contracted, the elastic element two (41) contracts and resets, and the extended protection area contracts and resets.

8. The umbrella-shaped microjets laser anti-backflow device according to claim 7, characterized in that: The telescopic assembly (43) includes a sliding rod (431). The umbrella unit (2221) has an inner cavity (432) for the sliding rod (431) to slide. The sliding rod (431) is slidably disposed in the inner cavity (432). The telescopic assembly (43) also includes an elastic element three (433) disposed in the inner cavity (432). The elastic element three (433) is used to provide elastic reset for the sliding of the sliding rod (431).

9. The umbrella-shaped microjets laser anti-backflow device according to claim 8, characterized in that: The second elastic element (41) and the first elastic element (34) are integrally formed structures, and the whole structure is an umbrella-shaped ring structure. The whole structure is installed between multiple umbrella blade units (2221) and multiple side plates (42). The umbrella-shaped ring structure includes the first elastic element (34) for compensating for the tilt angle adjustment gap and the second elastic element (41) for realizing edge elastic expansion and reset.

10. The umbrella-shaped microjets laser anti-backflow device according to claim 9, characterized in that: The inner umbrella (221) is fixedly connected to the mounting base (21) to form a fixed primary flow guiding structure.

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