Anti-backfire three-tube dual-purpose heavy-duty cutting torch

Abstract

The application discloses a backfire-proof three-tube dual-purpose heavy-duty cutting torch, which comprises a tail seat, a torch head and a gas conveying pipe connecting the tail seat and the torch head, wherein the gas conveying pipe comprises a high-pressure oxygen pipe, a heated oxygen pipe and a gas pipe which are independent of each other; the torch head is internally provided with a jet suction channel for oxygen to gas, and is also provided with a connecting part which can be externally connected with different types of nozzle; a plurality of groups of sealing surfaces are distributed on the connecting part in an axial direction; wherein the nozzle comprises a first type of nozzle and a second type of nozzle; when the first type of nozzle is connected with the connecting part, at least two groups of sealing surfaces are matched at the connecting surface; and when the second type of nozzle is connected with the connecting part, at least one group of sealing surfaces is matched at the connecting surface.

Description

Technical Field

[0001] This application relates to the field of cutting torch technology, and more specifically to a backfire-proof, three-barrel, dual-purpose heavy-duty cutting torch. Background Technology

[0002] Currently, in the field of industrial cutting and welding, heavy-duty cutting torches are commonly used tools that need to meet the requirements of high-intensity operations while also ensuring operational safety. Traditional cutting torches typically employ a dual-tube structure, with dual-tube suction-type cutting torches being widely used due to their simple structure. However, in these torches, the fuel gas and oxygen are pre-mixed during delivery, resulting in a large amount of mixed gas remaining in the pipe. Once backfire occurs, the flame can easily propagate backward along the pipe, posing a significant safety hazard.

[0003] In addition, the working pressure and medium characteristics of different nozzles vary significantly. Cutting nozzles need to withstand the dual pressure of high-pressure oxygen and mixed gas at the same time, which requires extremely high sealing reliability. Welding nozzles, on the other hand, only need to meet the low-pressure sealing requirements of mixed gas. The sealing surface design of the dual-tube cutting torch in related technologies cannot take into account the sealing requirements of different nozzles. Summary of the Invention

[0004] The purpose of this application is to provide a three-tube dual-purpose heavy-duty cutting torch that prevents backfire, thereby improving sealing reliability and reducing the risk of backfire while achieving multiple uses in one torch.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: A backfire-proof, three-tube, dual-purpose heavy-duty cutting torch is provided, comprising: a tailstock, a torch head, and a gas supply pipe connecting the two. The gas supply pipe includes an independent high-pressure oxygen pipe, a heated oxygen pipe, and a gas combustion pipe. The torch head has oxygen and gas combustion channels, and the oxygen-gas injection effect is completed within the torch head. The torch head also has a connecting portion for connecting different types of nozzles. The connecting portion has multiple sets of sealing surfaces spaced axially. The nozzles include a first type of nozzle and a second type of nozzle. When the first type of nozzle is connected to the connecting portion, at least two sets of sealing surfaces are adapted at the connecting surface. When the second type of nozzle is connected to the connecting portion, at least one set of sealing surfaces is adapted at the connecting surface.

[0006] As a preferred embodiment, the first type of nozzle is provided with a high-pressure oxygen direct passage chamber and a mixed gas annular chamber; the connecting part and the first type of nozzle form a first chamber, which is connected to the mixed gas annular chamber. The first chamber is used to mix the heating oxygen transported in the heating oxygen pipe and the gas transported in the gas pipe, and then spray it out from the mixed gas annular chamber; the high-pressure oxygen direct passage chamber is connected to the high-pressure oxygen pipe, and the high-pressure oxygen transported in the high-pressure oxygen pipe enters the high-pressure oxygen direct passage chamber and is sprayed out.

[0007] As another preferred embodiment, the multiple sets of sealing surfaces include a first sealing surface, a second sealing surface, and a third sealing surface distributed sequentially from top to bottom along the axial direction. The first sealing surface is adjacent to the second sealing surface, and a transition area is provided between the second sealing surface and the third sealing surface to provide a gap.

[0008] Further preferred, the anti-backfire three-tube dual-purpose heavy-duty cutting torch also includes an anti-backfire device, which is integrally formed with the tailstock.

[0009] Further preferably, the backfire prevention device includes an oxygen flame arrester and a gas flame arrester that are independently arranged. The oxygen flame arrester and the gas flame arrester have the same structure. The oxygen flame arrester is arranged on one side corresponding to the high-pressure oxygen pipe and the heated oxygen pipe, and the gas flame arrester is arranged on one side corresponding to the gas pipe.

[0010] Preferably, either the oxygen flame arrester or the gas flame arrester includes a flame arrestor tube, an input connector, and a one-way valve; the flame arrestor tube is embedded in the tailstock, and the outer wall of the input connector is fixedly connected to the tailstock; one end of the input connector extends into the flame arrestor tube to form an interference fit with the flame arrestor tube; the input connector has a first through hole and a second through hole communicating with the flame arrestor tube, the first through hole and the second through hole communicating with each other, the diameter of the first through hole being smaller than that of the second through hole, and the second through hole being used to connect with the one-way valve.

[0011] Preferably, a connector sleeve is provided on the side of the valve body inlet end of the one-way valve, and the center of the connector sleeve is provided with an inner chamfer structure with a first inclination angle.

[0012] Preferably, the anti-backfire three-tube dual-purpose heavy-duty cutting torch further includes a gas regulating valve assembly, which is connected to the tailstock. The gas regulating valve assembly is used to regulate the gas feed rate and includes a valve needle, a locking member, and an adjusting shaft. The adjusting shaft is connected to the tailstock, and the valve needle is connected to the adjusting shaft. The locking member is sleeved on the outer wall of the tailstock and has a stepped structure to stop the axial displacement of the adjusting shaft. The valve needle includes a tapered end, a middle part, and a tail part connected in sequence. The tapered end and the middle part are both placed in the valve cavity within the tailstock. The tapered end is used for sealing. The middle part is circumferentially locked to the valve cavity to restrict the circumferential rotation of the valve needle relative to the valve cavity. The tail part is rotatably connected to the adjusting shaft. By rotating the adjusting shaft, the valve needle is driven to move axially relative to the valve cavity to achieve sealing or opening of the valve body.

[0013] Furthermore, the tapered end is a tapered structure with a 6:1 taper.

[0014] Furthermore, the anti-backfire three-tube dual-purpose heavy-duty cutting torch also includes a high-pressure oxygen quick-opening assembly. This assembly is located on the top of the tailstock and is used to adjust the high-pressure oxygen feed rate. The assembly includes a handle, a valve cover, a compression spring, a spring seat, and a quick-opening rubber-coated shaft. The valve cover is connected to the top of the tailstock. One end of the quick-opening rubber-coated shaft passes through the valve cover and extends into the tailstock to form a seal with the inlet end of the high-pressure oxygen tube. The other end of the quick-opening rubber-coated shaft is connected to the handle to form a lever structure outside the tailstock. An extension boss is provided on the side of the quick-opening rubber-coated shaft near the high-pressure oxygen tube. The spring seat is connected to the extension boss, and the compression spring is located between the spring seat and the valve cover.

[0015] Compared with existing technologies, the advantages of this application are as follows: This application document, through the differentiated configuration of multiple sets of sealing surfaces, enables the same nozzle head to be compatible with first-type and second-type nozzles that have different structures and sizes. The first-type nozzle needs to be adapted to at least two sets of sealing surfaces to meet its functional requirements, such as the multi-port sealing requirements brought about by dual channels of high-pressure oxygen and mixed gas; the second-type nozzle only needs to be adapted to at least one set of sealing surfaces, simplifying the connection structure of non-cutting nozzles, realizing one nozzle for multiple uses, eliminating the need to design nozzle heads separately for different nozzles, and reducing equipment costs and operational complexity.

[0016] For the first type of nozzle that needs to withstand higher pressure and mixed gas, multiple sealing surfaces can reduce the amount of gas remaining in the connection gap through step-by-step sealing, thereby reducing the risk of flame entering the gas pipeline through the connection during backfire. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the cutting torch in related technologies.

[0018] Figure 2 This is a schematic diagram of a three-barrel dual-purpose heavy-duty cutting torch.

[0019] Figure 3 This is another structural diagram of a three-barrel dual-purpose heavy-duty cutting torch.

[0020] Figure 4 This is a structural diagram of the nozzle position in a three-barrel dual-purpose heavy-duty cutting torch.

[0021] Figure 5 This is a schematic diagram of the structure for connecting the first type of nozzle to the nozzle head.

[0022] Figure 6 This is a schematic diagram of the structure for connecting the second type of nozzle to the nozzle head.

[0023] Figure 7 This is a schematic diagram of the first type of gun nozzle.

[0024] Figure 8 This is a schematic diagram of the structure of the second type of gun nozzle.

[0025] Figure 9 This is a schematic diagram of the backfire prevention device.

[0026] Figure 10 This is a schematic diagram of the input connector.

[0027] Figure 11 This is a schematic diagram of a one-way valve.

[0028] Figure 12 This is a structural diagram showing the position of the tailstock of a three-barrel dual-purpose heavy-duty cutting torch.

[0029] Figure 13 This is a schematic diagram of the gas regulating valve assembly.

[0030] Figure 14 This is a schematic diagram of the structure of a high-pressure oxygen quick-opening assembly.

[0031] Figure 15 This is a cross-sectional view of the gun head.

[0032] In the diagram: 1', cutting torch; 10', torch head; 20', nozzle; 30', high-pressure oxygen delivery pipe; 40', gas-oxygen mixing pipe; 50', regulating valve assembly; 60', high-pressure oxygen regulating handwheel; 70', heating oxygen regulating handwheel; 80', gas regulating handwheel; 90', handheld position;

[0033] 1. Three-tube dual-purpose heavy-duty cutting torch; 2. Nozzle; 10. Tailstock; 11. Valve chamber; 20. Nozzle head; 21. Connecting part; 211. First sealing surface; 212. Second sealing surface; 213. Third sealing surface; 22. First chamber; 23. Locking nut; 24. High-pressure oxygen gas zone; 25. Injection channel; 30. Gas supply pipe; 31. High-pressure oxygen pipe; 32. Heated oxygen pipe; 33. Gas combustion pipe; 40. Type I nozzle; 41. Mixed gas annular cavity; 42. High-pressure oxygen straight-through cavity; 43. Cylindrical surface; 44. First inclined surface; 45. Second inclined surface; 50. Type II nozzle; 51. Third inclined surface;

[0034] 60. Backfire prevention device; 61. Oxygen flame arrestor; 62. Gas flame arrestor; 621. Flame arrestor tube; 622. Input end connector; 6221. First through hole; 6222. Second through hole; 6223. Internal connector; 6224. External connector; 623. One-way valve; 6231. Connector sleeve; 6232. Inner chamfer; 624. Elastic element base; 625. Elastic element; 626. Bearing steel ball; 627. One-way valve port; 63. Anti-loosening plate; 64. Sealing ring;

[0035] 70. Gas regulating valve assembly; 71. Valve needle; 711. Conical end; 712. Middle section; 713. Tail end; 72. Locking element; 73. Adjusting shaft; 74. Handwheel; 75. Steel wire ring; 76. First sealing ring;

[0036] 80. High-pressure oxygen quick-opening assembly; 81. Handle; 82. Valve cover; 83. Compression spring; 84. Spring seat; 85. Quick-opening rubber-coated shaft; 851. Extension boss; 852. Valve port; 86. Second sealing ring; 87. Third sealing ring; 88. Washer; 89. Elastic cylindrical pin; 90. Handheld position; 100. Heated oxygen regulating valve; 110. Decorative cover; 120. Solid metal rivet; 130. Machine-made screw. Detailed Implementation

[0037] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0038] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0039] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0040] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0041] See Figure 1In related technologies, a traditional cutting torch 1' consists of a torch head 10', a nozzle 20', and two metal tubes. One tube is a gas-oxygen mixing tube 40', which is used to transport the oxygen-fuel (lower end) mixture to the nozzle to heat the metal and form a molten pool. The other tube is a high-pressure oxygen delivery tube 30', which is specifically used to transport high-pressure oxygen (upper end) through the central hole of the nozzle to blow away the molten metal solution in the molten pool and form a fissure. Most conventional oxygen-acetylene (including other fuels) cutting torches 1' adopt an injection-suction structure and are composed of the two metal tubes mentioned above. After the oxygen and gas are proportionally adjusted, the oxygen injects the gas, which is then delivered to the nozzle through a single metal tube, ignited, and ejected to form a heating flame, thus forming a molten pool on the metal surface.

[0042] Meanwhile, in order to control the heating intensity, a regulating valve for adjusting the flow rate of gas and oxygen is provided at the handheld position 90' of the cutting torch 1', which together constitutes the regulating valve assembly 50'. The flow rate of high-pressure oxygen is adjusted by the high-pressure oxygen regulating handwheel 60', which distributes oxygen to the high-pressure oxygen pipeline and sends it to the center of the nozzle to blow away the liquid metal in the molten pool, creating fissures and ultimately separating the entire piece of metal at a predetermined position. The heating oxygen is adjusted by the heating oxygen regulating handwheel 70', and the gas flow rate is adjusted by the gas regulating handwheel 80'. Therefore, the adjustment precision brought about by the specific internal structure of the regulating valve will directly affect the optimal mixing ratio, which plays a decisive role in the combustion thermal efficiency and is also the key to cost saving.

[0043] In order to adapt to workpieces of different sizes and working conditions, the oxy-acetylene anti-backfire three-tube dual-purpose heavy-duty cutting torch 1 in this application can replace different types of nozzles 2 and is connected to the nozzle head 20 by locking nut 23, specifically a hexagonal nut.

[0044] Therefore, in a preferred embodiment, see Figures 2 to 14 This application provides a backfire-proof, three-tube dual-purpose heavy-duty cutting torch 1, including: a tailstock 10, a torch head 20, and a gas supply pipe 30 connecting the two. The gas supply pipe 30 includes an independent high-pressure oxygen pipe 31, a heated oxygen pipe 32, and a gas supply pipe 33. The cross-sections of the three pipes are arranged in a triangular shape. High-pressure oxygen and heated oxygen flow into the high-pressure oxygen pipe 31 and the heated oxygen pipe 32 respectively along the X1 direction, while gas flows into the gas supply pipe 33 along the X2 direction. That is, the backfire-proof, three-tube dual-purpose heavy-duty cutting torch 1 in this application adopts an isobaric structure, and the gas and combustion-supporting gas required for heating metal are delivered to the torch head 20 through their respective metal pipes. See [link to application]. Figure 15 In the first chamber 22 inside the nozzle 20, the injection and suction mixing takes place. Since the injection and suction mixing occurs inside the nozzle 20, the mixed oxygen and gas are directly ejected from the nozzle 2, so the probability of backfire is much lower than that of the two-tube injection and suction type cutting torch 1'.

[0045] However, while isobaric cutting torches are less prone to backfire, their lower gas pressure limits the gas flow rate, thus restricting cutting capability. Therefore, see [reference needed]. Figure 15 The backfire-proof three-tube dual-purpose heavy-duty cutting torch 1 provided in this application has an additional injection channel 25 inside the torch head 20. The injection channel 25 utilizes the injection effect generated by the high-pressure oxygen flow from the heated oxygen pipe 32 to actively induce and accelerate the delivery of gas, thereby effectively overcoming the technical bottleneck of weak flame intensity and limited cutting ability caused by insufficient gas pressure in isobaric cutting torches. Furthermore, this design enables the backfire-proof three-tube dual-purpose heavy-duty cutting torch 1 in this application to have the characteristics of being less prone to backfire and having a large gas flow rate.

[0046] Specifically, the gas supply pipe 30 consists of three seamless stainless steel pipes with an outer diameter of 9.5mm: a high-pressure oxygen pipe 31, a heated oxygen pipe 32, and a gas pipe 33, each 420mm in length. One end of the gas supply pipe 30 is brazed to the corresponding mounting hole of the tailstock 10, and the other end is brazed to the corresponding mounting hole of the nozzle 20, forming a triangular shape. For ease of handling, a handheld sleeve is provided at the end near the tailstock 10, on the handheld position 90 of the anti-backfire three-tube dual-purpose heavy-duty cutting torch 1. The sleeve is made of non-ferrous metal H62 (copper) or 6061A (aluminum) profile, and the surface can be made into striped or mesh knurled patterns for an aesthetically pleasing appearance. The end of the tailstock 10 has a stepped structure that matches the inner diameter of the sleeve. The step provides positioning, and the two are further secured by solid metal rivets 120 to prevent displacement. The other end of the sleeve has a bowl-shaped decorative cap 110, which is fixed to the sleeve with machine screws 130.

[0047] See Figures 4 to 8 The gun head 20 is provided with a connecting part 21 for connecting different types of nozzles 2. The connecting part 21 has multiple sets of sealing surfaces distributed axially at intervals. The nozzles 2 include a first type nozzle 40 and a second type nozzle 50. When the first type nozzle 40 is connected to the connecting part 21, at least two sets of sealing surfaces are adapted at the connecting surface. When the second type nozzle 50 is connected to the connecting part 21, at least one set of sealing surfaces is adapted at the connecting surface. The first type nozzle 40 is preferably as follows: Figure 7 The gas cutting nozzle shown, the second type of nozzle 50 is preferably a type such as... Figure 8 The welding nozzle shown is either a general-purpose third-party gas cutting nozzle or a third-party welding nozzle available on the market.

[0048] Preferably, the multiple sealing surfaces in this application include a first sealing surface 211, a second sealing surface 212, and a third sealing surface 213 distributed sequentially from top to bottom along the axial direction. The first sealing surface 211 is adjacent to the second sealing surface 212, and a transition area is provided between the second sealing surface 212 and the third sealing surface 213 to allow for spacing.

[0049] As a preferred embodiment, the first type of nozzle 40 is provided with a high-pressure oxygen direct passage chamber 42 and a mixed gas annular chamber 41; the connecting part 21 and the first type of nozzle 40 form a first chamber 22, which is connected to the mixed gas annular chamber 41. The first chamber 22 is used to heat the oxygen for heating transported in the oxygen pipe 32 and the gas transported in the gas pipe 33, which are then mixed after being injected into the nozzle 20 and ejected from the mixed gas annular chamber 41; the high-pressure oxygen direct passage chamber 42 is connected to the high-pressure oxygen pipe 31, and the high-pressure oxygen transported in the high-pressure oxygen pipe 31 enters the high-pressure oxygen gas area 24 and is ejected from the high-pressure oxygen direct passage chamber 42.

[0050] In order to dissipate the radiant heat of the nozzle 2 as quickly as possible and maintain the temperature of the nozzle 2 within an acceptable range, this embodiment uses... Figure 7 Taking the gas cutting nozzle shown as an example, the gas cutting nozzle is made of copper. The nozzle has a central through hole, which is the high-pressure oxygen direct-flow chamber 42. The diameter of this hole is proportional to the thickness of the metal plate being cut. Around the central hole, multiple evenly distributed small holes radiate outwards, forming the mixing gas annular chamber 41. Preferably, six such chambers are provided. The diameter of the small holes is related to the area being heated; the larger the diameter, the larger the area being heated. The gas cutting nozzle has at least two conical surfaces, namely a first inclined surface 44 and a second inclined surface 45. When the gas cutting nozzle is connected to the nozzle head 20, the first chamber 22 is located between the first inclined surface 44 and the second inclined surface 45. The lower end of the nozzle head 20 has an external thread, which, through a locking nut 23, connects the gas cutting nozzle to the nozzle head 20. After connection, the gas and heated oxygen can mix within the first chamber 22.

[0051] In actual manufacturing, due to the existence of manufacturing tolerances, it is almost impossible to make the first inclined surface 44 and the second inclined surface 45 simultaneously contact the two conical surfaces of the second sealing surface 212 and the third sealing surface 213, respectively. This is because when the first inclined surface 44 on the gas cutting nozzle is in complete contact with the second sealing surface 212, the second inclined surface 45 on the gas cutting nozzle will be restricted from moving, thus creating a gap.

[0052] Therefore, this application adds a first sealing surface 211 to the end of the nozzle 2. The first sealing surface 211 is a cylindrical sealing structure, that is, the outer diameter of the high-pressure oxygen inlet end of the original gas cutting nozzle is precision machined to form a cylindrical surface 43, which then makes an interference fit with the first sealing surface 211 at the high-pressure oxygen outlet of the nozzle head 20. The interference range is controlled within the elastic deformation range of the gas cutting nozzle metal to form a cylindrical sealing surface. Preferably, the length of the cylindrical sealing surface is controlled to be 2~3mm. If it is too short, it will not meet the sealing requirements. If it is too long, the mating surface will be difficult to separate when disassembling the gas cutting nozzle and the nozzle head 20.

[0053] Furthermore, during the actual assembly of the gas cutting nozzle and the nozzle head 20, it is essential to ensure that the conical third sealing surface 213 of the connecting part 21 of the nozzle head 20 is sealed and fitted with the second inclined surface 45 on the gas cutting nozzle. Otherwise, the mixture of heated oxygen and fuel gas in the first chamber 22 will leak and ignite upon contact with the open flame emitted from the ignited gas cutting nozzle. This is unacceptable in welding and cutting processes and will result in a major safety accident. Therefore, when the cylindrical surface 43 in the gas cutting nozzle forms the first sealing surface 211 of the connecting part 21 of the nozzle head 20, the locking nut 23 on the nozzle head 20 is rotated further. This forces the gas cutting nozzle to move axially upward until the third sealing surface 213 fits with the second inclined surface 45. Through the interference fit between the first sealing surface 211 and the cylindrical surface 43, combined with the fit between the third sealing surface 213 and the second inclined surface 45, the area of ​​heated oxygen and fuel gas mixture and the high-pressure oxygen area are completely isolated.

[0054] The purpose of the second sealing surface 212 provided in the connecting part 21 of the nozzle 20 in this application is that when the user selects a commercially available nozzle, such as a third-party gas cutting nozzle, the nozzle 2 can still be sealed by the universal second sealing surface 212 to make it usable, so as to improve the applicability of the three-tube dual-purpose heavy-duty cutting torch 1 in this application.

[0055] Meanwhile, to facilitate the switching between gas cutting and welding, this application provides a second type of nozzle 50, such as... Figure 8 The welding nozzle shown has a third inclined surface 51. When the welding nozzle is connected to the connecting part 21 of the nozzle head 20, it is only necessary to replace the gas cutting nozzle with a welding nozzle. Figure 6 As shown, the welding nozzle has a third inclined surface 51 for fitting with the third sealing surface 213 on the connecting part 21 to form a seal. Similarly, the welding nozzle is connected to the gun head 20 by locking nut 23. Since high-pressure oxygen is not required during welding, there is only one mixed gas area chamber composed of heating oxygen and fuel gas between the gun head 20 and the welding nozzle.

[0056] Therefore, this application document, through differentiated configurations of multiple sets of sealing surfaces, enables the same nozzle head 20 to be compatible with first-type nozzles 40 and second-type nozzles 50, which have different structures and dimensions. The first-type nozzle 40 needs to be adapted to at least two sets of sealing surfaces to meet its functional requirements, such as the multi-port sealing requirements brought about by dual channels for high-pressure oxygen and mixed gas; the second-type nozzle 50 only needs to be adapted to at least one set of sealing surfaces, simplifying the connection structure of non-cutting nozzles 2, realizing multi-purpose use of one nozzle, eliminating the need to design nozzle heads 20 separately for different nozzles 2, and reducing equipment costs and operational complexity.

[0057] Due to differences in working pressure and medium characteristics among different nozzle types 2, such as gas cutting nozzles needing to withstand the dual pressure of high-pressure oxygen and mixed gas, while welding nozzles only require a mixed gas seal, a multi-set sealing surface design can provide graded sealing for nozzle type 2: the first type of nozzle 40 forms multiple barriers through two or more sets of sealing surfaces, effectively preventing high-pressure gas leakage; the second type of nozzle 50 can meet its sealing requirements under its working pressure with only one sealing surface, ensuring reliability while avoiding structural redundancy.

[0058] Combining the isobaric structure of the anti-backfire three-tube dual-purpose heavy-duty cutting torch 1 in this application, the combustion gas and oxygen mix in the torch head 20, and the heated oxygen forms a jet suction on the gas passage in the torch head 20. With the help of multiple sets of sealing surfaces, the backfire propagation path can be further blocked.

[0059] For the first type of nozzle 40, which needs to withstand higher pressure and mixed gas, multiple sets of sealing surfaces can effectively reduce the amount of gas leakage at the connection by sealing in stages, and reduce the risk of flame entering the gas supply pipe 30 through the connection part 21 during backfire.

[0060] Further optimization reveals that the anti-backfire three-tube dual-purpose heavy-duty cutting torch 1 also includes an anti-backfire device 60, which is integrally set with the tailstock 10, and the tailstock 10 is preferably made of copper alloy.

[0061] Further preferred, the backfire prevention device 60 includes an oxygen flame arrester 61 and a gas flame arrester 62, which are independently arranged. The oxygen flame arrester 61 and the gas flame arrester 62 have the same structure, and the only difference between them is the material and the air volume. The oxygen flame arrester 61 is set on the side corresponding to the high-pressure oxygen pipe 31 and the heated oxygen pipe 32, and the gas flame arrester 62 is set on the side corresponding to the gas pipe 33.

[0062] Preferably, either the oxygen flame arrester 61 or the gas flame arrester 62 includes a flame arrestor tube 621, an input connector 622, and a one-way valve 623. The flame arrestor tube 621 is embedded in the tailstock 10, and the outer wall of the input connector 622 is fixedly connected to the tailstock 10. One end of the input connector 622 extends into the flame arrestor tube 621 to form an interference fit with the flame arrestor tube 621. The input connector 622 has a first through hole 6221 and a second through hole 6222 that communicate with the flame arrestor tube 621. The first through hole 6221 and the second through hole 6222 are interconnected. The diameter of the first through hole 6221 is smaller than that of the second through hole 6222. The second through hole 6222 is used to connect to the one-way valve 623.

[0063] In a preferred embodiment, the gas flame arrestor tube 621 in the gas flame arrestor 62 is made of sintered stainless steel with a filtration accuracy of 100µm (approximately 200 mesh). The gas flame arrestor tube 621 has a cylindrical structure with an inner surface area preferably of 11.8 cm². The flow velocity v is selected as 8 m / s, and the flow rate is chosen at 50%, resulting in a permeable flow rate of 21.3 m³ / h. Since copper and its alloy particles have a catalytic decomposition effect on acetylene, stainless steel is chosen to prevent the gas flame arrestor tube 621 from exploding. The oxygen flame arrestor tube 621 in the oxygen flame arrestor 61 uses a lower-cost sintered copper filtration structure, with a permeable flow rate as high as 20 m³ / h and a filtration accuracy of 150µm (equivalent to 100 mesh). The hexagonal structure of the outer connector 6224 of the input connector 622 of the gas flame arrestor 62 is engraved with a left-hand thread connection mark.

[0064] It should also be noted that metal flame-retardant components, including sintered metal components, should be made from copper-free materials. At temperatures below 500°C, acetylene may explode and decompose in the presence of a catalyst. Copper, brass, silver, and other metals and metal oxides can all induce acetylene decomposition, acting as catalysts. The smaller the catalyst particles, the stronger their effect. Copper and its oxides are the most reactive substances in inducing the explosive decomposition of acetylene at lower temperatures. Therefore, copper sintered materials are not permitted as flame-retardant materials in acetylene systems; hence, the gas flame arrestor 621 in this application is made of sintered stainless steel.

[0065] Therefore, taking the gas flame arrestor 62 as an example, the inner hole of the flame arrestor tube 621 in the gas flame arrestor 62 is connected to the inner connector 6223 of the input connector 622, and the two are interference fit. A stepped hole is provided at the center of the head of the input connector, such as... Figure 10As shown, the stepped hole specifically consists of a first through hole 6221 and a second through hole 6222. The diameter of the second through hole 6222 is larger than that of the first through hole 6221, and preferably 10 mm. A one-way valve 623 is installed inside the second through hole 6222. The one-way valve 623 specifically includes an elastic element base 624, an elastic element 625, a bearing steel ball 626, and a connector sleeve 6231. The connector sleeve 6231 is located on the gas inlet side of the valve body of the one-way valve 623. The elastic element base 624 is preferably a spring seat structure, and the elastic element 625 is a standard cylindrical compression spring structure. The connector sleeve 6231 has a through hole in its center. The center position of the connector sleeve 6231 and the bearing steel ball 626 form a sealing surface structure. The length of this sealing surface should not be less than 1 mm. The sealing surface needs to be formed by grinding, and the surface roughness should not be less than Ra0.4. The colored area should not be less than 40%, and there should be no axial defects penetrating the colored part. After the sealing surface of the connector sleeve 6231 passes inspection, a bearing steel ball 626 with a diameter of 5mm and a standard cylindrical compression spring, i.e., elastic element 625, are installed. Then, the thread (M8) of the elastic element base 624 is used to seal and tighten it. Furthermore, through the setting of the bearing steel ball 626, when the air flow is large during use, the rotation of the bearing steel ball 626 itself will not affect the elastic element 625. This effectively avoids the situation where the plug plate structure used in related technologies flips over and causes the elastic element 625 to fail.

[0066] The assembled one-way valve 623 is pressed into the second through hole 6222 of the input connector 622. The two are press-fitted, improving the seal between the one-way valve 623 and the input connector 622. Figure 11 As shown, the connector sleeve 6231 has an inner chamfer 6232 structure with a first inclination angle at its center. The first inclination angle is preferably 60° to form a conical connector sleeve 6231 structure, which facilitates the mating with the spherical connector of the external rubber hose connector. When the hexagonal locking nut on the external rubber hose connector is tightened with the thread of the external connector 6224 of the input end connector 622, it ensures a good seal at the connection under a pressure of 2.5MPa. The connector sleeve 6231 has an internal thread (M6) at its center to facilitate the installation and removal of the one-way valve 623. The assembled backfire prevention device 60 has a sealing ring 64 at the threaded connection between the input end connector 622 and the tail seat 10. The sealing ring 64 is a standard rubber sealing ring 64, used to achieve a seal between the backfire prevention device 60 and the tail seat 10.

[0067] Furthermore, the assembled gas flame arrestor 62 and oxygen flame arrestor 61 are screwed into the corresponding threaded holes of the tailstock 10 in sequence. The input end connector 622 is tightened and slightly adjusted so that the outer hexagon of the input end connector 622 is aligned with the two hexagonal holes of the connector anti-loosening plate 63. Then, the anti-loosening plate 63 is fixed to the tailstock 10 with screws. At this time, when installing or removing the external rubber hose, the input end connector 622 will not loosen and there will be no loosening phenomenon.

[0068] Specifically, the operation procedure of the anti-backfire device 60 is as follows: After connecting the rubber hose to the gas cylinder and pressure reducing valve, and connecting the other end of the rubber hose to the tailstock 10, and after checking the sealing and completing the preparations, ignite the cutting torch to begin operation. It is necessary to ensure that the torque of the elastic element 625 in the anti-backfire device 60 is sufficient to push open the bearing steel ball 626 when the external gas pressure is 0.04 MPa, and to meet the gas consumption requirements. When the external backfire gas flow occurs, because its pressure is much greater than 0.04 MPa, the bearing steel ball 626, under the dual action of the backfire gas flow and the compression and reset of the elastic element 625, immediately closes the one-way valve port 627, thereby preventing backfire.

[0069] Among them, see Figure 12 Both the oxygen heating regulating valve 100 and the gas regulating valve assembly 70 adopt a needle valve structure. To facilitate the operator's usage habits, two mutually perpendicular planes are arranged on the handheld position 90. The oxygen heating regulating valve 100 is located on the side of the operator, and the gas regulating valve assembly 70 is located below the operator.

[0070] Preferably, the anti-backfire three-tube dual-purpose heavy-duty cutting torch 1 further includes a gas regulating valve assembly 70, which is connected to the tailstock 10. The gas regulating valve assembly 70 is used to regulate the gas feed rate and includes a valve needle 71, a locking element 72, a handwheel 74, a wire ring 75, and an adjusting shaft 73. The locking element 72 is specifically a locking nut. The adjusting shaft 73 is connected to the tailstock 10, the valve needle 71 is connected to the adjusting shaft 73, and the locking element 72 is sleeved on the outer wall of the tailstock 10. The locking element 72 has a stepped structure to stop the backfire. The axial displacement of the adjusting shaft 73; the valve needle 71 includes a tapered end 711, a middle part 712 and a tail part 713 connected in sequence. The tapered end 711 and the middle part 712 are both placed in the valve cavity 11 in the tail seat 10. The tapered end 711 is used for sealing. The middle part 712 is circumferentially locked with the valve cavity 11 to restrict the circumferential rotation of the valve needle 71 relative to the valve cavity 11. The tail part 713 is rotatably connected to the adjusting shaft 73. By rotating the adjusting shaft 73, the valve needle 71 is driven to move axially relative to the valve cavity 11 to achieve sealing or opening of the valve body.

[0071] The oxygen heating regulating valve 100 is designed, manufactured, and installed according to the general needle valve structure, which will not be described in detail here. According to GB7899 "Gas Cylinder Pressure Regulators for Welding, Cutting and Similar Processes" 6.2.2, the design, processing, and assembly of acetylene pressure regulators should ensure that the outlet pressure does not exceed 0.15 MPa. Due to the low pressure, the general needle valve structure cannot meet the high flow rate requirements of heavy-duty cutting torches. Therefore, if it is necessary to cut through steel plates with a thickness of 250 mm or more, the needle valve structure must be innovatively adjusted. Simultaneously, due to the special chemical composition of the fuel gas, a fuel regulating valve assembly 70 needs to be specifically designed for low-pressure fuel gases such as acetylene. See [link to relevant documentation] for details. Figure 13 The structure is shown.

[0072] Specifically, one end of the valve needle 71 is provided with a standard left-hand thread (M5 left) which is connected to the internal thread of the adjusting shaft 73. The middle part 712 is specifically a hexagonal structure so as to cooperate with the hexagonal structure in the valve cavity 11 located in the corresponding position in the tailstock 10 to form a slide to restrict the rotation of the valve needle 71. The tail 713 of the valve needle 71 is connected to the adjusting shaft 73 by a thread, so that when the adjusting shaft 73 rotates, the valve needle 71 as a whole only moves axially and does not rotate.

[0073] Meanwhile, the tapered end 711 of the valve needle 71 is machined into a cone shape with a 6:1 taper (10°) and forms a sealing surface with the valve body located at the corresponding position in the tailstock 10. The outer diameter of the large end of the tapered end 711 of the valve needle 71 is 3.2 mm and the total length is 3 mm, which is the key to ensuring that the needle valve can achieve the maximum flow rate when it is fully open relative to the valve body. The large end of the adjusting shaft 73 has an internal thread (M5 left) that connects to the tail 713 of the valve needle 71. The outer diameter of the large end has a groove for installing a sealing ring. The sealing ring is also a standard rubber sealing ring, which is located in the valve body gap corresponding to the sealing adjusting shaft 73 and the tail seat 10. The outer diameter of the small end of the adjusting shaft 73 has knurled straight lines. After the locking member 72 is correctly inserted, the handwheel 74 is press-fitted into the end of the adjusting shaft 73 with knurled straight lines. The locking member 72 has a through hole in the middle to facilitate the passage of the adjusting shaft 73. The internal thread of the locking member 72 is connected to the external thread located at the corresponding position of the tail seat 10 to restrict the axial displacement of the adjusting shaft 73.

[0074] Furthermore, a wire ring 75 is provided at the junction of the small end of the adjusting shaft 73 and the locking member 72. The wire ring 75 is open and warped, with a planar distance of approximately 1 mm between its beginning and end. Its function is to compensate for the space formed between the stepped structure on the adjusting shaft 73 that abuts against the wire ring 75 and the locking member 72 when the locking member 72 is fully tightened and contacts the threaded end face of the valve body located inside the tailstock 10. The handwheel 74 is made of non-ferrous metal profile with a striped multi-petal plum blossom pattern on its outer surface. The inner hole on its end face is interference-fitted with the knurled end of the adjusting shaft 73.

[0075] The valve body sealing surface within the tailstock 10 also features a 6:1 tapered bore. This sealing surface serves as the mating surface for the tapered end 711 of the valve needle 71. The tapered bore is precision reamed using a 6:1 special tapered reamer and then ground. A colorimetric inspection is performed on the tapered end 711 of the valve needle 71, ensuring that the colored area is not less than 40% and that there are no longitudinal defects penetrating the colored area. The lower end of the tailstock 10 has an external thread connecting to the locking element 72 at its relative mounting position, thereby limiting the displacement of the adjusting shaft 73. A steel wire ring 75 is also installed for compensation. Preferably, the threaded connection between the locking element 72 and the tailstock 10 is sealed with anaerobic sealant.

[0076] Further, see Figure 14 The anti-backfire three-tube dual-purpose heavy-duty cutting torch 1 also includes a high-pressure oxygen quick-opening assembly 80, which is located on the top of the tailstock 10. The high-pressure oxygen quick-opening assembly 80 is used to adjust the high-pressure oxygen feed rate. The high-pressure oxygen quick-opening assembly 80 includes a handle 81, a valve cover 82, a compression spring 83, a spring seat 84, a second sealing ring 86, a third sealing ring 87, a washer 88, an elastic cylindrical pin 89, and a quick-opening rubber-coated shaft 85. The valve cover 82 is connected to the top of the tailstock 10. One end of the quick-opening rubber-coated shaft 85 passes through the valve cover 82 and extends into the tailstock 10 to form a seal with the air inlet end of the high-pressure oxygen tube. The other end of the quick-opening rubber-coated shaft 85 is connected to the handle 81 to form a lever structure on the outside of the tailstock 10. The quick-opening rubber-coated shaft 85 has an extension boss 851 on the side near the high-pressure oxygen tube 31. The spring seat 84 is connected to the extension boss 851, and the compression spring 83 is located between the spring seat 84 and the washer 88.

[0077] The valve cover 82 is threadedly connected to the valve body located at the top of the tailstock 10. The seal is formed by a third sealing ring 87, which is a standard rubber sealing ring. The valve cover 82 has a stepped hole at its center. A standard metal washer 88 and a cylindrical compression spring 83 are installed at the larger end of the hole. A small hole near the top passes through a quick-opening rubber-coated shaft 85. The valve cover 82 and the quick-opening rubber-coated shaft 85 are sealed by a second sealing ring 86 located at the top of the small hole. The bottom of the quick-opening rubber-coated shaft 85 has a cylindrical extended boss 851. A spring seat 84 is placed on the top of the boss. The cylindrical part below the boss is wrapped with fluororubber and vulcanized to increase the connection strength. The fluororubber wrapping and the valve body inner cavity boss located at the top of the tailstock 10 form an elastic sealing surface. The cylindrical part at the top of the quick-opening rubber-coated shaft 85 has a groove, which is combined with the handle 81 to connect and open the quick-opening valve. The handle 81 is made of stainless steel and is streamlined. One end is hooked to the quick-opening rubber-coated shaft 85. It forms a lever by setting a fulcrum at the corresponding position on the top of the tailstock 10. The fulcrum shaft is realized by a standard elastic cylindrical pin 89, which is installed in the hole at the top of the tailstock 10. After all parts are adjusted, anaerobic sealant is applied to the threaded connection between the valve cover 82 and the tailstock 10 to seal it.

[0078] When using the high-pressure oxygen quick-opening assembly 80, simply press the handle 81 lightly. Under the combined action of oxygen pressure and the lever of the handle 81, the quick-opening valve assembly can be opened quickly and completely. To close, simply release the handle 81. Under the elastic reset action of the cylindrical compression spring 83, the quick-opening valve will be closed quickly and easily. It is very convenient to use and can achieve zero maintenance.

[0079] Seal the threaded outlet of nozzle 20 with a special plug, close the high-pressure oxygen quick-opening assembly, the heated oxygen regulating valve 100 and the gas regulating valve assembly 70, introduce 4MPa nitrogen into the gas inlet at the tail end of tailstock 10, open each gas circuit valve one by one, maintain pressure for 5 minutes to conduct a strength test, and pass if there is no deformation or abnormal noise during the test. Reduce the pressure to 2.5MPa, maintain pressure for 30 minutes to conduct a sealing test, and pass if there is no pressure drop at room temperature.

[0080] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A backfire-resistant, three-barreled, dual-purpose heavy-duty cutting torch, characterized in that, include: Tailstock, nozzle, and gas supply pipe connecting the two, wherein the gas supply pipe includes an independent high-pressure oxygen pipe, a heated oxygen pipe, and a gas combustion pipe; The gun head is provided with oxygen and gas passages, and the oxygen's suction effect on the gas is completed within the gun head. The gun head is also provided with a connecting part that can be used to connect different types of nozzles. The connecting part is provided with multiple sets of sealing surfaces distributed axially at intervals. The nozzle includes a first type of nozzle and a second type of nozzle. When the first type of nozzle is connected to the connecting part, at least two sets of sealing surfaces are adapted at the connecting surface. When the second type of nozzle is connected to the connecting part, at least one set of sealing surfaces is adapted at the connecting surface. The multiple sets of sealing surfaces include a first sealing surface, a second sealing surface, and a third sealing surface distributed sequentially from top to bottom along the axial direction. The first sealing surface is adjacent to the second sealing surface, and a transition area is provided between the second sealing surface and the third sealing surface to provide a gap. The first type of nozzle is an oxy-fuel cutting nozzle. The oxy-fuel cutting nozzle has at least two conical surfaces, namely a first inclined surface and a second inclined surface, and also has a cylindrical surface. The first sealing surface corresponds to a cylindrical sealing structure. When the cylindrical surface in the oxy-fuel cutting nozzle forms a first seal with the first sealing surface of the connecting part of the nozzle head, the locking nut on the nozzle head is rotated further, thereby forcing the oxy-fuel cutting nozzle to move axially upward until the third sealing surface fits against the second inclined surface. Thus, through the interference fit between the first sealing surface and the cylindrical surface, and the fit between the third sealing surface and the second inclined surface, a sealing and isolation is achieved.

2. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in claim 1, characterized in that, The first type of nozzle is provided with a high-pressure oxygen direct passage chamber and a mixed gas annular chamber; The connecting part and the first type of nozzle form a first chamber. The first chamber is connected to the mixed gas annular cavity. The first chamber is used to mix the heating oxygen transported in the heating oxygen pipe and the gas transported in the gas pipe, and spray it out from the mixed gas annular cavity. The high-pressure oxygen direct passage is connected to the high-pressure oxygen pipe, and the high-pressure oxygen transported in the high-pressure oxygen pipe enters the high-pressure oxygen direct passage to be ejected.

3. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in claim 1, characterized in that, It also includes a backfire prevention device, which is integrally formed with the tailstock.

4. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in claim 3, characterized in that, The backfire prevention device includes an oxygen flame arrester and a gas flame arrester that are independently arranged. The oxygen flame arrester and the gas flame arrester have the same structure. The oxygen flame arrester is arranged on one side corresponding to the high-pressure oxygen pipe and the heated oxygen pipe, and the gas flame arrester is arranged on one side corresponding to the gas pipe.

5. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in claim 4, characterized in that, Each of the oxygen flame arrestor and the gas flame arrestor includes a flame arrestor tube, an inlet connector and a one-way valve. The flame arrestor tube is embedded in the tailstock, and the outer wall of the input end connector is fixedly connected to the tailstock. One end of the input end connector extends into the flame arrestor tube to make an interference fit with the flame arrestor tube. The input terminal connector is provided with a first through hole and a second through hole that connect to the flame arrester. The first through hole and the second through hole are interconnected. The diameter of the first through hole is smaller than that of the second through hole. The second through hole is used to connect to the one-way valve.

6. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in claim 5, characterized in that, A connector sleeve is provided on the side of the valve body inlet end of the one-way valve, and the center of the connector sleeve has an inner chamfer structure with a first tilt angle.

7. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in any one of claims 1-6, characterized in that, It also includes a gas regulating valve assembly, which is connected to the tailstock and is used to regulate the gas feed rate, including a valve needle, a locking element and an adjusting shaft; The adjusting shaft is connected to the tailstock, the valve needle is connected to the adjusting shaft, the locking member is sleeved on the outer wall of the tailstock, and the locking member has a stepped structure to stop the axial displacement of the adjusting shaft. The valve needle includes a tapered end, a middle section, and a tail section connected in sequence. The tapered end and the middle section are both placed in the valve cavity within the tail seat. The tapered end is used for sealing. The middle section is circumferentially locked to the valve cavity to restrict the valve needle from rotating circumferentially relative to the valve cavity. The tail section is rotatably connected to the adjusting shaft. By rotating the adjusting shaft, the valve needle is driven to move axially relative to the valve cavity to achieve sealing or opening of the valve body.

8. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in claim 7, characterized in that, The tapered end is a tapered structure with a 6:1 taper.

9. The anti-backfire three-barrel dual-purpose heavy-duty cutting torch as described in any one of claims 1-6, characterized in that, It also includes a high-pressure oxygen quick-opening assembly, which is located on the top of the tailstock and is used to adjust the high-pressure oxygen feed rate. The high-pressure oxygen quick-opening assembly includes a handle, a valve cover, a compression spring, a spring seat, and a quick-opening rubber-coated shaft. The valve cover is connected to the top of the tailstock. One end of the quick-opening rubber-coated shaft passes through the valve cover and extends into the tailstock to form a seal with the air inlet end of the high-pressure oxygen tube. The other end of the quick-opening rubber-coated shaft is connected to the handle to form a lever structure on the outside of the tailstock. The quick-opening rubber-coated shaft has an extended boss on the side near the high-pressure oxygen pipe. The spring seat is connected to the extended boss, and the compression spring is located between the spring seat and the valve cover.

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