Nitrogen and oxygen mixing device for laser cutting machine

Abstract

The nitrogen and oxygen mixing device for the laser cutting machine comprises a nitrogen tank and an oxygen tank, three sets of connecting pipes are installed on the nitrogen tank, and the three sets of connecting pipes on the nitrogen tank communicate with a first pressure gauge, a first pressure reducing valve and a gas mixer correspondingly; meanwhile, an outlet pipe of the pressure reducing valve I is communicated with an inlet pipe of a filter I, an outlet pipe of the filter I is communicated with a gas inlet pipe of a gas flow controller I, and a gas outlet pipe of the gas flow controller I is communicated with a gas mixer. According to the nitrogen and oxygen mixing device for the laser cutting machine, a simple structure of inputting nitrogen and oxygen and outputting nitrogen and oxygen mixed gas is adopted, a nitrogen making machine can be replaced, most functions of the nitrogen making machine are achieved, and the price is lower than that of the nitrogen making machine; the purity of each gas can be accurately controlled, so that the mixing of nitrogen and oxygen can be continuously and accurately adjusted, and the cutting requirements of workpieces with different thicknesses and different materials are met.

Description

Technical Field

[0001] The invention relates to the field of laser cutting machines, in particular to a nitrogen and oxygen mixing device for laser cutting machines. Background Art

[0002] Laser cutting machines mainly use nitrogen, oxygen and air as auxiliary gases during cutting. These three gases mainly play a role in combustion or purging during cutting. With the development of laser cutting technology, the cutting process is becoming more and more perfect. When cutting plates of different thicknesses and materials, different gases are selected, and the cutting efficiency and quality are also different.

[0003] The advantages and disadvantages of the three gases in laser cutting are as follows: 1. Nitrogen: mainly used as purge gas, with high pressure, fast cutting speed and good cutting quality; 2. Oxygen: It mainly oxidizes the workpiece and plays a role in combustion. It has low pressure, slow cutting speed, high cost, best cutting quality and can cut thick plates. 3. Air: It can oxidize the workpiece and serve as a purge gas. It has low cost and is suitable for cutting thin plates.

[0004] From the above analysis of advantages and disadvantages, it can be seen that how to use gas correctly during cutting becomes the top priority to improve cutting efficiency and cutting quality. For workpieces with thicker plates and higher surface requirements, oxygen cutting has good quality but slow speed; nitrogen cutting has fast speed but poor quality. This makes the laser cutting machine unable to meet the cutting needs of workpieces of different thicknesses and different materials, and unable to improve cutting efficiency and cutting quality. Summary of the invention

[0005] The object of the present invention is to provide a nitrogen and oxygen mixing device for a laser cutting machine to solve the defects mentioned in the above background technology.

[0006] To achieve the above-mentioned purpose, a nitrogen and oxygen mixing device for a laser cutting machine is provided, comprising a nitrogen tank and an oxygen tank, wherein three groups of connecting pipes are respectively installed on the nitrogen tank, and the three groups of connecting pipes on the nitrogen tank are respectively connected with a pressure gauge, a pressure reducing valve and a gas mixer, and at the same time, an outlet pipe of the pressure reducing valve is connected with an inlet pipe of a filter, and an outlet pipe of the filter is connected with an inlet pipe of a gas flow controller, and an outlet pipe of the gas flow controller is connected with the gas mixer, and a nitrogen main pipe, a nitrogen branch pipe, an oxygen main pipe, a pressure gauge mounting seat, a container connecting pipe and an oxygen content detection seat are respectively installed on the gas mixer, and the nitrogen main pipe located at the top of the gas mixer is connected with the gas flow controller, and at the same time, a nitrogen branch pipe installed on the side wall of the nitrogen main pipe is connected with the nitrogen tank through a pipeline, and is located at the gas mixer. The oxygen main pipe at the bottom is connected to the oxygen outlet pipe of the gas flow controller 2, the pressure gauge mounting seat and the container connecting pipe on the middle side wall of the gas mixer are respectively connected to the pressure gauge 3 and the gas storage container, and the oxygen content detection seat in the middle of the back of the gas mixer is fixedly connected to the analyzer detection probe through a flange, and the analyzer detection probe is electrically connected to the oxygen content analyzer through a wiring harness, and the outlet pipe of the gas storage container is connected to the gas output pipe through a ball valve; the gas output pipe transports nitrogen and oxygen mixed gas to the laser cutting machine; two groups of connecting pipes are respectively installed on the oxygen tank, and the two groups of connecting pipes on the oxygen tank are respectively installed with the pressure gauge 2 and the pressure reducing valve 2, and the outlet pipe of the pressure reducing valve 2 is connected to the inlet pipe of the filter 2, and the outlet pipe of the filter 2 is connected to the inlet pipe of the gas flow controller 2.

[0007] Preferably, a pressure gauge is installed on the gas storage container, and the gas mixer is connected to the gas output pipe through the gas storage container and the ball valve respectively.

[0008] Preferably, the pressure reducing valve 1, the pressure reducing valve 2, the gas flow controller 1, the gas flow controller 2, and the oxygen content analyzer are all electrically connected to the control unit.

[0009] Preferably, connecting sections are fixedly provided at both the upper and lower ends of the gas mixer, and the cross-sections of the connecting sections are all conical, and the two sets of connecting sections are screwed and fixed to the nitrogen main pipe and the oxygen main pipe respectively through flanges, and the central axes of the nitrogen main pipe and the oxygen main pipe are arranged to coincide.

[0010] Preferably, a nitrogen uniform distribution disk is fixedly installed on the upper side of the gas mixer, and an oxygen uniform distribution disk is fixedly installed on the lower side of the gas mixer, and the oxygen uniform distribution disk and the nitrogen uniform distribution disk are symmetrical structures about the center point of the gas mixer.

[0011] Preferably, the cross-sections of the oxygen and nitrogen uniform distribution plates are both "U"-shaped, and a plurality of overflow pipes are evenly and fixedly arranged on the oxygen and nitrogen uniform distribution plates.

[0012] Preferably, the distance between two adjacent groups of overflow pipes is consistent, and the top height of the overflow pipe is greater than the bottom plate height of the nitrogen uniform distribution disk. The overflow pipe is cylindrically arranged, and the nitrogen enters the interior of the gas mixer evenly through the nitrogen uniform distribution disk and the multiple groups of overflow pipes thereon, and at the same time, the oxygen enters the interior of the gas mixer evenly through the oxygen uniform distribution disk and the multiple groups of overflow pipes thereon.

[0013] Preferably, a positioning seat is fixedly mounted on the circumferential outer wall of the gas mixer, and a positioning groove matching the size of the positioning block is opened inside the positioning seat. At the same time, the positioning block is fixedly arranged on the back of the oxygen content analyzer, and the positioning block is inserted into the positioning groove.

[0014] Preferably, the oxygen content analyzer is positioned and installed on the outside of the gas mixer through a positioning seat and a positioning block, and the cross-sections of the positioning seat and the positioning block are dovetail-shaped.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a simple structure of inputting nitrogen and oxygen and outputting nitrogen-oxygen mixed gas, which can replace the nitrogen generator and realize most of the functions of the nitrogen generator, and the price is lower than that of the nitrogen generator; the purity of each gas can be accurately controlled, so that the mixture of nitrogen and oxygen can be continuously and accurately adjusted to meet the cutting needs of workpieces of different thicknesses and different materials, and improve the cutting efficiency and cutting quality; it has the advantages of simple structure, wide adjustment range, high accuracy, strong sustainability, etc.; it improves the cutting efficiency and cutting quality; 2. The present invention can evenly disperse the gases in the mixer by arranging the nitrogen uniform distribution disk and the oxygen uniform distribution disk after the nitrogen and oxygen enter the mixer; when the nitrogen or oxygen passes through a large number of overflow pipes, the flow rate and flow direction thereof will be redistributed to avoid the situation where the local concentration is too high near the air inlet, so that the gas in the mixer is more evenly distributed before entering the detection area, which is conducive to the oxygen content analyzer to obtain representative samples and improve the detection accuracy of the oxygen content analyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, further serve to explain the principles of the invention and to enable those skilled in the relevant art to make and use the invention.

[0017] Figure 1 This is a schematic diagram of the principle flow of the nitrogen / oxygen mixing device of the present invention; Figure 2This is a simplified control flow chart of the nitrogen / oxygen mixing device of the present invention; Figure 3 This is a schematic diagram of the structure of the gas mixer of the present invention; Figure 4 for Figure 3 Bottom view of Figure 5 for Figure 3 A top view of Figure 6 for Figure 3 Rear view of.

[0018] In the figure: 1. nitrogen tank; 10. pressure gauge 1; 11. pressure reducing valve 1; 12. filter 1; 13. gas flow controller 1; 2. oxygen tank; 20. pressure gauge 2; 21. pressure reducing valve 2; 22. filter 2; 23. gas flow controller 2; 3. gas mixer; 30. nitrogen uniform distribution plate; 301. overflow pipe; 31. connecting section; 32. nitrogen main pipe; 33. nitrogen branch pipe; 34. pressure gauge mounting seat; 35. container connecting pipe; 36. oxygen uniform distribution plate; 37. oxygen main pipe; 38. oxygen content detection seat; 39. analyzer detection probe; 391. positioning seat; 392. positioning block; 4. pressure gauge 3; 5. pressure gauge 4; 6. gas storage container; 61. ball valve; 62. gas output pipe; 7. oxygen content analyzer; 8. control unit. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Specific implementation method 1: Please refer to Figure 1-6The present invention provides a technical solution: a nitrogen and oxygen mixing device for a laser cutting machine, comprising a nitrogen tank 1 and an oxygen tank 2, wherein three groups of connecting pipes are respectively installed on the nitrogen tank 1, and the three groups of connecting pipes on the nitrogen tank 1 are respectively connected with a pressure gauge 10, a pressure reducing valve 11 and a gas mixer 3, and the outlet pipe of the pressure reducing valve 11 is connected with the inlet pipe of a filter 12, and the outlet pipe of the filter 12 is connected with the inlet pipe of a gas flow controller 13, and the outlet pipe of the gas flow controller 13 is connected with the gas mixer 3, and a nitrogen main pipe 32, a nitrogen branch pipe 33, an oxygen main pipe 37, a pressure gauge mounting seat 34, a container connecting pipe 35 and an oxygen content detection seat 38 are respectively installed on the gas mixer 3, and the nitrogen main pipe 32 located at the top of the gas mixer 3 is connected to the gas flow controller 13, and the nitrogen branch pipe 33 installed on the side wall of the nitrogen main pipe 32 is connected with the nitrogen tank 1 through a pipeline, and the nitrogen main pipe 32 is connected with the gas flow controller 13 through a pipeline, and the nitrogen main pipe 32 is connected with the gas flow controller 13 through a pipeline, and the nitrogen main pipe 33 is connected with the nitrogen main pipe 1 ... The oxygen main pipe 37 at the bottom of the gas mixer 3 is connected to the oxygen outlet pipe of the gas flow controller 23, the pressure gauge mounting seat 34 and the container connecting pipe 35 on the middle side wall of the gas mixer 3 are connected to the pressure gauge 34 and the gas storage container 6 respectively, and the oxygen content detection seat 38 in the middle of the back of the gas mixer 3 is fixedly connected to the analyzer detection probe 39 through a flange, and the analyzer detection probe 39 is electrically connected to the oxygen content analyzer 7 through a wiring harness, and the outlet pipe of the gas storage container 6 is connected to the gas output pipe 62 through a ball valve 61; the gas output pipe 62 transports nitrogen and oxygen mixed gas to the laser cutting machine; two groups of connecting pipes are respectively installed on the oxygen tank 2, and the two groups of connecting pipes on the oxygen tank 2 are respectively installed with a pressure gauge 20 and a pressure reducing valve 21, and the outlet pipe of the pressure reducing valve 21 is connected to the inlet pipe of the filter 22, and the outlet pipe of the filter 22 is connected to the inlet pipe of the gas flow controller 23.

[0021] Working principle: The programmable controller is used to adjust the pressure reducing valve 11, the pressure reducing valve 21, the gas flow controller 13, and the gas flow controller 23, a total of four variables, so that a certain volume of nitrogen and oxygen enter the gas mixer 3, and the required nitrogen concentration is achieved after mixing. The oxygen concentration in the gas mixer 3 is detected by the oxygen content analyzer 7, and the value is fed back to the control unit 8. The control unit 8 continues to adjust the above four variables according to the feedback, and finally realizes the continuous and stable output of a mixed gas of a certain concentration; like Figure 1As shown, nitrogen is divided into two paths, one path directly enters the gas mixer 3, and the other path passes through a pressure reducing valve 11, a filter 12, and a gas flow controller 13 in sequence before entering the gas mixer 3. A pressure gauge 10 detects the intake pressure of nitrogen; oxygen also passes through a pressure reducing valve 21, a filter 22, and a gas flow controller 23 in sequence before entering the gas mixer 3. A pressure gauge 20 detects the intake pressure of oxygen; wherein the pressure reducing valve 11, the pressure reducing valve 21, the gas flow controller 13, and the gas flow controller 23 are four variables, which can be adjusted through the programming program inside the control unit 8 so that nitrogen and oxygen are fully Mix to reach a preset gas concentration, and the pressure gauge three 4 detects the mixed gas pressure in the gas mixer 3; the oxygen content analyzer 7 detects the oxygen concentration of the mixed gas in the gas mixer 3, and feeds back the value to the control unit 8, and the control unit 8 continues to adjust the four variables of the pressure reducing valve one 11, the pressure reducing valve two 21, the gas flow controller one 13, and the gas flow controller two 23 according to the feedback to achieve a mixed oxygen concentration of 1-15% and a mixing accuracy of ±1%; the mixed gas enters the gas storage container 6, and the pressure gauge four 5 detects the pressure in the container, and finally outputs it to the laser cutting machine to cut workpieces of different thicknesses and different materials; like Figure 2 As shown, first define the mixed gas concentration A0, four variables are preset according to the system, pressure reducing valve 11 is preset to B1, pressure reducing valve 21 is preset to B2, gas flow controller 13 is preset to C1, gas flow controller 23 is preset to C2, and the oxygen content analysis value A1 is obtained according to the above preset values; Calculate the mixed gas adjustment coefficient K based on the preset analysis algorithm, where K=(A0-A1) / A0; Dynamically adjust the values ​​of B1, B2, C1, and C2 so that K approaches 0 infinitely, and obtain a stable mixed gas with a defined concentration; In summary, the nitrogen / oxygen mixing device of the laser cutting machine involved in this patent has the following advantages: 1. Simple structure and low price. This device adopts a simple structure of inputting nitrogen and oxygen and outputting nitrogen-oxygen mixed gas. It can replace the nitrogen generator and realize most of the functions of the nitrogen generator. It is cheaper than the nitrogen generator. It can accurately control the purity of each gas so that the mixture of nitrogen and oxygen can be continuously and accurately adjusted to meet the cutting needs of workpieces of different thicknesses and different materials, and improve cutting efficiency and cutting quality. It has the advantages of simple structure, wide adjustment range, high accuracy and strong sustainability. 2. High accuracy and stable gas output; the control unit 8 of the device can collect and analyze the mixed gas information, and then feed it back to the control unit 8 to dynamically adjust the gas output volume and pressure to meet the requirements of the cutting process of workpieces of different thicknesses and different materials, and achieve high-quality cutting; 3. Small footprint and easy maintenance: This device can be integrated in a gas circuit cabinet. Compared with the nitrogen generator with complex structure, it occupies a small space and is easy to maintain.

[0022] Specific implementation method 2: This implementation method is a further limitation of specific implementation method 1. A pressure gauge 4 5 is installed on the gas storage container 6, and the gas mixer 3 is connected to the gas output pipe 62 through the gas storage container 6 and the ball valve 61 respectively.

[0023] Specific implementation method three: This implementation method is a further limitation of specific implementation method one, and pressure reducing valve one 11 , pressure reducing valve two 21 , gas flow controller one 13 , gas flow controller two 23 , and oxygen content analyzer 7 are all electrically connected to control unit 8 .

[0024] The upper and lower ends of the gas mixer 3 are fixedly provided with connecting sections 31, and the cross-sections of the connecting sections 31 are all conical, and the two groups of connecting sections 31 are screwed and fixed to the nitrogen main pipe 32 and the oxygen main pipe 37 through flanges, and the central axes of the nitrogen main pipe 32 and the oxygen main pipe 37 are overlapped.

[0025] Specific implementation method four: This implementation method is a further limitation of specific implementation method one. A nitrogen uniform distribution disk 30 is fixedly installed on the upper side of the interior of the gas mixer 3, and an oxygen uniform distribution disk 36 is fixedly installed on the lower side of the interior of the gas mixer 3. At the same time, the oxygen uniform distribution disk 36 and the nitrogen uniform distribution disk 30 are symmetrical structures about the center point of the gas mixer 3.

[0026] The cross-sections of the oxygen uniform distribution plate 36 and the nitrogen uniform distribution plate 30 are both “U”-shaped, and a plurality of overflow pipes 301 are evenly and fixedly arranged on the oxygen uniform distribution plate 36 and the nitrogen uniform distribution plate 30 .

[0027] Specific embodiment five: This embodiment is a further limitation of specific embodiment four. The distance between two adjacent groups of overflow pipes 301 is consistent, and the top height of the overflow pipe 301 is greater than the bottom plate height of the nitrogen uniform distribution disk 30. The overflow pipe 301 is cylindrically arranged, and nitrogen evenly enters the interior of the gas mixer 3 through the nitrogen uniform distribution disk 30 and the multiple groups of overflow pipes 301 thereon, and at the same time, oxygen evenly enters the interior of the gas mixer 3 through the oxygen uniform distribution disk 36 and the multiple groups of overflow pipes 301 thereon.

[0028] A positioning seat 391 is fixedly installed on the circumferential outer wall of the gas mixer 3, and a positioning groove matching the size of the positioning block 392 is opened inside the positioning seat 391. At the same time, the positioning block 392 is fixedly arranged on the back of the oxygen content analyzer 7, and the positioning block 392 is inserted into the inside of the positioning groove.

[0029] Specific embodiment six: This embodiment is a further limitation of specific embodiment five. The oxygen content analyzer 7 is positioned and installed on the outside of the gas mixer 3 through a positioning seat 391 and a positioning block 392, and the cross-sections of the positioning seat 391 and the positioning block 392 are dovetail-shaped.

[0030] The working mode of the gas mixer 3 is as follows: the upper and lower ends of the gas mixer 3 are fixedly provided with connecting sections 31, and the cross-sections of the connecting sections 31 are all conical, and the two groups of connecting sections 31 are respectively screwed and fixed to the nitrogen main pipe 32 and the oxygen main pipe 37 through flanges; the nitrogen inside the nitrogen main pipe 32 impacts the nitrogen uniform distribution disk 30 from the connecting section 31, and evenly enters the interior of the gas mixer 3 in an overflow manner through a large number of overflow pipes 301; similarly, the oxygen inside the oxygen main pipe 37 impacts the oxygen uniform distribution disk 36 from the connecting section 31, and evenly enters the interior of the gas mixer 3 in an overflow manner through a large number of overflow pipes 301; When nitrogen and oxygen enter the mixer, the setting of the nitrogen uniform distribution plate 30 and the oxygen uniform distribution plate 36 can make the gas evenly dispersed in the mixer; when nitrogen or oxygen passes through a large number of overflow pipes 301, its flow rate and flow direction will be redistributed to avoid the situation of excessive local concentration near the air inlet, so that the gas in the mixer is more evenly distributed before entering the detection area, which is conducive to the oxygen content analyzer to obtain representative samples and improve the detection accuracy of the oxygen content analyzer 7.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nitrogen and oxygen mixing device for a laser cutting machine, comprising a nitrogen tank (1) and an oxygen tank (2), characterized in that: The nitrogen tank (1) is respectively provided with three groups of connecting pipes, and the three groups of connecting pipes on the nitrogen tank (1) are respectively connected to a pressure gauge (10), a pressure reducing valve (11) and a gas mixer (3), and the outlet pipe of the pressure reducing valve (11) is connected to an inlet pipe of a filter (12), and the outlet pipe of the filter (12) is connected to an inlet pipe of a gas flow controller (13), and the outlet pipe of the gas flow controller (13) is connected to the gas mixer (3), and the gas mixer ( A nitrogen main pipe (32), a nitrogen branch pipe (33), an oxygen main pipe (37), a pressure gauge mounting seat (34), a container connecting pipe (35) and an oxygen content detection seat (38) are respectively installed on the gas mixer (3), and the nitrogen main pipe (32) located at the top of the gas mixer (3) is connected to the gas flow controller (13), and the nitrogen branch pipe (33) installed on the side wall of the nitrogen main pipe (32) is connected to the nitrogen tank (1) through a pipeline, and the oxygen main pipe (37) located at the bottom of the gas mixer (3) is connected to the gas flow controller (13). The oxygen outlet pipe of the gas mixer (23) is connected to the second gas mixer (23), the pressure gauge mounting seat (34) and the container connecting pipe (35) on the middle side wall of the gas mixer (3) are connected to the pressure gauge (4) and the gas storage container (6) respectively, and the oxygen content detection seat (38) in the middle of the back of the gas mixer (3) is fixedly connected to the analyzer detection probe (39) through a flange, and the analyzer detection probe (39) is electrically connected to the oxygen content analyzer (7) through a wiring harness, and the outlet of the gas storage container (6) is connected to the second gas mixer (23). The pipe is connected to the gas output pipe (62) through a ball valve (61); the gas output pipe (62) delivers nitrogen and oxygen mixed gas to the laser cutting machine; two sets of connecting pipes are respectively installed on the oxygen tank (2), and the two sets of connecting pipes on the oxygen tank (2) are respectively installed with a pressure gauge (20) and a pressure reducing valve (21), and the outlet pipe of the pressure reducing valve (21) is connected to the inlet pipe of the filter (22), and the outlet pipe of the filter (22) is connected to the inlet pipe of the gas flow controller (23).

2. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 1, characterized in that: A pressure gauge (5) is installed on the gas storage container (6), and the gas mixer (3) is connected to the gas output pipe (62) through the gas storage container (6) and the ball valve (61).

3. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 1, characterized in that: The pressure reducing valve 1 (11), the pressure reducing valve 2 (21), the gas flow controller 1 (13), the gas flow controller 2 (23), and the oxygen content analyzer (7) are all electrically connected to the control unit (8).

4. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 1, characterized in that: The gas mixer (3) is fixedly provided with connecting sections (31) at both the upper and lower ends, and the cross-sections of the connecting sections (31) are both conical, and the two sets of connecting sections (31) are respectively screwed and fixed to the nitrogen main pipe (32) and the oxygen main pipe (37) through flanges, and the central axes of the nitrogen main pipe (32) and the oxygen main pipe (37) are arranged to coincide with each other.

5. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 1, characterized in that: A nitrogen evenly distributing disk (30) is fixedly mounted on the upper side of the interior of the gas mixer (3), and an oxygen evenly distributing disk (36) is fixedly mounted on the lower side of the interior of the gas mixer (3), and the oxygen evenly distributing disk (36) and the nitrogen evenly distributing disk (30) are symmetrical structures about the center point of the gas mixer (3).

6. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 5, characterized in that: The cross-sections of the oxygen uniform distribution plate (36) and the nitrogen uniform distribution plate (30) are both arranged in a "U" shape, and a plurality of groups of overflow pipes (301) are evenly and fixedly arranged on the oxygen uniform distribution plate (36) and the nitrogen uniform distribution plate (30).

7. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 6, characterized in that: The distance between two adjacent groups of overflow pipes (301) is consistent, and the top height of the overflow pipe (301) is greater than the bottom height of the nitrogen uniform distribution plate (30). The overflow pipe (301) is cylindrical, and nitrogen uniformly enters the interior of the gas mixer (3) through the nitrogen uniform distribution plate (30) and the multiple groups of overflow pipes (301) thereon, while oxygen uniformly enters the interior of the gas mixer (3) through the oxygen uniform distribution plate (36) and the multiple groups of overflow pipes (301) thereon.

8. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 1, characterized in that: A positioning seat (391) is fixedly mounted on the circumferential outer wall of the gas mixer (3), and a positioning groove matching the size of the positioning block (392) is provided inside the positioning seat (391). The positioning block (392) is fixedly arranged on the back of the oxygen content analyzer (7), and the positioning block (392) is inserted into the interior of the positioning groove.

9. The nitrogen and oxygen mixing device for a laser cutting machine according to claim 8, characterized in that: The oxygen content analyzer (7) is positioned and installed on the outside of the gas mixer (3) through a positioning seat (391) and a positioning block (392), and the cross-sections of the positioning seat (391) and the positioning block (392) are arranged in a dovetail shape.

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