Spheroidal graphite cast iron pipeline welding ring welding device

Abstract

The invention provides a nodular cast iron pipeline welding ring welding device, which relates to the technical field of nodular cast iron pipeline welding, and comprises a pipeline conveying mechanism, a pipeline rotating mechanism, a lifting support frame, a transverse moving mechanism, a welding gun fixing mechanism, a wire feeder, a welding power supply and an air supply device. The pipeline rotating mechanism is arranged in the middle of the conveying mechanism to drive the pipe body to rotate at constant speed; a transverse moving mechanism on the side face of the lifting supporting frame can drive the welding gun to accurately move in the vertical direction and the horizontal direction. The welding gun fixing mechanism is mounted on the fixing frame and has a fine adjustment function to ensure a constant distance between a welding nozzle and a pipe wall; the welding power source and the gas supply device provide energy and shielding gas for welding through a pipeline. Optionally, a welding fume collecting device and a high-temperature-resistant fence can be integrated. According to the automatic ring welding device, online automation of ring welding operation is achieved, and the welding efficiency, the quality stability and the operation environment friendliness are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the field of ductile cast iron pipe welding technology, and particularly relates to a ductile cast iron pipe welding ring welding device. BACKGROUND

[0002] Ductile cast iron pipes are widely used in pressure pipeline engineering such as water supply, drainage and gas transmission due to their high strength, good toughness and corrosion resistance. In the production process, a reinforcing ring or a sealing ring (hereinafter referred to as "welding ring") is often welded at one end of the finished pipe to meet the requirements of specific engineering or connection. The welding ring is usually fixedly connected with the outer wall of the pipe body by fusion welding, which can play a role in starting and stopping.

[0003] At present, there are mainly two ways to complete the welding of the outer ring in the industry: Manual welding: the operator holds the welding gun and welds along the circumference of the pipe end. Although this method has high flexibility, it requires high skills of the operator, and the stability of the welding quality is difficult to guarantee, and defects such as uneven weld, incomplete penetration and slag inclusion are prone to occur. At the same time, manual welding is low in efficiency, high in labor intensity, high in production cost, and difficult to adapt to the production rhythm of batch production.

[0004] Special ring welding machine: there are also some special ring automatic welding equipment in the prior art. Such equipment usually has a clamping mechanism that can be opened and closed. When working, the equipment needs to be moved to the pipe end and accurately centered and clamped on the pipe, so that the welding gun head rotates around the pipe wall for welding. Although this method improves the automation level and quality consistency of welding to some extent, it still has significant drawbacks: first, the clamping and centering process of the equipment is complicated, and the operation cycle of "loading-clamping-welding-unclamping-unloading" needs to be repeated for each pipe, which is time-consuming and has limited improvement in overall production efficiency; second, the equipment is usually independent, and cannot be efficiently integrated with the continuous production line of ductile cast iron pipes (such as roller conveying line), which breaks the continuous flow of materials and forms a bottleneck process in the production rhythm.

[0005] Therefore, the existing ductile cast iron pipe outer ring welding method, whether manual or semi-automatic, has the problems of inconvenient operation, low integration and low production efficiency, which is difficult to meet the needs of modern efficient and intelligent pipeline production line.

[0006] It should be noted that the above content belongs to the technical cognition of the skilled person. Since the technical content in this field is vast and complex, the above content of the present application does not necessarily constitute the prior art. SUMMARY

[0007] 1. The technical problem to be solved by the present application: The application provides a ductile cast iron pipeline welding ring welding device to solve the technical problems in the background art.

[0008] 2. Technical solutions: To achieve the above-mentioned purposes, the technical solutions provided by the application are as follows: a ductile cast iron pipeline welding ring welding device, comprising a pipeline conveying mechanism for conveying and positioning the ductile cast iron pipeline; A pipeline rotating mechanism is arranged at the middle part of the two pipeline conveying mechanisms and is used for carrying and driving the ductile cast iron pipeline to rotate around its own axis. A lifting support frame is arranged adjacent to the pipeline rotating mechanism. A transverse moving mechanism is installed on the lifting support frame and can vertically move along the lifting support frame. A welding gun fixing mechanism is connected to the end of the transverse moving mechanism through a fixing frame, and the transverse moving mechanism can drive the fixing frame and the welding gun fixing mechanism to move forward and backward in the horizontal direction. A wire feeder is installed on the fixing frame. A welding power supply and a gas feeding device are arranged on the side of the lifting support frame, and the output ends thereof are connected to the wire feeder and the welding gun fixing mechanism through high-temperature-resistant pipelines. The welding nozzle of the welding gun installed on the welding gun fixing mechanism can be adjusted and kept in contact with the outer wall of the ductile cast iron pipeline placed on the pipeline rotating mechanism. During welding, the pipeline rotating mechanism drives the ductile cast iron pipeline to rotate at a constant speed, the wire feeder feeds the wire, and the welding power supply and the gas feeding device work, so that the automatic welding of the continuous annular weld on the outer wall of the ductile cast iron pipeline is completed.

[0009] The pipeline conveying mechanism described in the application is used for receiving, supporting and conveying the ductile cast iron pipeline from the previous process. The mechanism is usually composed of two parallel arranged roller tracks, forming a conveying channel, and the length and spacing thereof can be adjusted according to the specifications of the pipeline.

[0010] The pipeline rotating mechanism is embeddedly arranged at the middle part of the pipeline conveying mechanism. The ductile cast iron pipeline can be conveyed by a travelling crane or a forklift. When the ductile cast iron pipeline is conveyed in place, the pipeline rotating mechanism is started to reliably clamp and drive the ductile cast iron pipeline to rotate at a constant speed around its own central axis.

[0011] The lifting support frame is fixedly installed on the foundation of the production line and is located on one side of the pipeline conveying mechanism. The structure adopts a solid steel frame, and the side surface can be integrated with a control cabinet. The welding power supply and the gas feeding device, including an argon / carbon dioxide mixed gas cylinder and a pressure reducing valve, are arranged at the back side of the lifting support frame, which is convenient for centralized management and maintenance.

[0012] The lateral moving mechanism is installed on the front of the lifting support frame by a slider or a guide rail. The whole lateral moving mechanism is lifted in the vertical direction. The welding height can be accurately set by the switch control of the side control cabinet, so as to easily adapt to various pipe diameters of the ductile iron pipe and ensure that the welding wire of the welding torch always aligns with the highest point of the pipe, i.e. the predetermined position of the outer ring seam.

[0013] The fixing frame is rigidly connected to the front end of the lateral moving mechanism. The lateral moving mechanism itself also has a horizontal moving function, so that the fixing frame can be driven to move in the direction of the pipe axis, i.e. the front and back direction.

[0014] The wire feeder is fixedly installed on one side of the fixing frame and contains a wire feeding wheel and a pressing mechanism to continuously and stably push the welding wire out of the welding wire reel. The welding torch fixing mechanism is installed on the other side of the fixing frame opposite to the wire feeder to firmly lock the welding torch in the optimal welding posture. The welding wire of the welding torch is adjusted to gently contact or keep a constant small distance from the outer wall of the ductile iron pipe.

[0015] The output cable of the welding power source, the gas pipe of the gas feeding device and the wire feeding hose of the wire feeder are bundled together, wrapped with a high-temperature-resistant corrugated pipe or a winding pipe for protection, pass through the wire feeder and are finally connected to the welding torch to provide energy, protective gas and filler material for the welding torch.

[0016] The working process of the device is as follows: Firstly, a ductile iron pipe is moved to the working position by the pipe conveying mechanism or hoisting equipment, so that one end of the pipe is suspended above the pipe rotating mechanism. Then, the operator controls the side control cabinet to control the lifting of the lateral moving mechanism to make the welding torch reach the height corresponding to the pipe diameter, controls the horizontal movement of the lateral moving mechanism to make the welding torch reach the axial position required by the pipe end and finally makes the welding wire of the welding torch perfectly fit the predetermined welding point of the pipe wall.

[0017] After the positioning is completed, the automatic welding program is started. The pipe rotating mechanism is first started to drive the ductile iron pipe to rotate at a constant speed matched with the welding process. Then, the welding power source is powered on, the gas feeding device feeds the protective gas and the wire feeder starts to push the welding wire. The welding torch is successfully ignited and the welding starts. Since the pipe continuously rotates, the welding wire continuously and internally extended from the welding torch can be continuously and uniformly deposited on the outer surface of the pipe to form a continuous, uniform and well-sealed ring-shaped weld.

[0018] After the welding is completed, the functional units are sequentially stopped, the pipe rotating mechanism is stopped and the welding head is lifted and returned to the original position. The welded pipe can be conveyed to the next process by the conveying mechanism to complete a complete working cycle.

[0019] In conclusion, the application solves the problems of unstable quality of traditional manual welding and low integration and long auxiliary time of special ring welding machine by ingenious mechatronic design.

[0020] Further, the pipe rotating mechanism comprises two symmetrical door type support seats, two groups of support rollers are rotatably installed on the top of each door type support seat, first chain wheels are installed on the outer side ends of the rotating shafts of the support rollers, the two first chain wheels on the same door type support seat are located in different vertical planes, rotating shafts driven by first driving motors are further arranged on the bottoms of the door type support seats, four second chain wheels are correspondingly installed on the rotating shafts, the first chain wheels and the second chain wheels in the same vertical plane are connected through a transmission chain, and the first driving motor is a double-output-shaft motor, the output shafts at both ends of the motor are connected to the rotating shafts on the two door type support seats through couplings.

[0021] Further, the top of the door type support seat is a meandering frame structure, a plurality of spaced mounting holes are symmetrically formed on the meandering frame structure along the length direction of the meandering frame structure, the support rollers are installed on the meandering frame structure through an assembled bearing seat, the assembled bearing seat comprises a fixed block and a concave positioning block, the fixed block is selectively fixed on the mounting holes in different positions through bolts, the concave positioning block is connected to the top of the fixed block, the combination part of the fixed block and the concave positioning block jointly forms a complete rotating hole, a bearing is installed in the rotating hole, and the rotating shaft of the support roller is supported in the bearing.

[0022] Further, the lifting support frame comprises a fixed base, a support column, a fixed table, a second driving motor, a rotating lead screw and a lifting vertical plate, the fixed base is fixed to the ground through foundation bolts, the support column is vertically arranged on the top of the fixed base, the fixed table is connected to the top end of the support column, the second driving motor is installed on the fixed table, the output shaft of the second driving motor vertically extends downward and is connected to the rotating lead screw, and the rotating lead screw and the screw nut arranged on the back of the lifting vertical plate form a threaded transmission pair.

[0023] Further, two sides of the support column are symmetrically provided with lifting positioning tracks; the lifting vertical plate is slidably connected with the lifting positioning tracks through L-shaped fixing plates, one side of the L-shaped fixing plate is matched with the lifting positioning tracks through a sliding block, and the other side is fixedly connected with the side surface of the lifting vertical plate; a shielding plate is detachably installed at the bottom outer side of the L-shaped fixing plate, and one stroke switch is arranged at each of the upper and lower ends of the side surface of the lifting positioning track, and the triggering positions of the two stroke switches correspond to the upper and lower limit positions of the shielding plate when the shielding plate ascends and descends with the lifting vertical plate.

[0024] Further, the horizontal moving mechanism comprises a horizontal support plate, support sliding rails, sliding positioning blocks, a rack, a gear and a third driving device; the horizontal support plate is connected with the lifting vertical plate through the support sliding rails fixed on two sides of the horizontal support plate, right-angle positioning blocks symmetrically arranged are fixed on the front surface of the lifting vertical plate, the sliding positioning blocks are installed on the right-angle positioning blocks, and the sliding positioning blocks and the support sliding rails form a sliding pair; the rack is fixedly installed at the bottom of the horizontal support plate; a placing gap is formed at the rear side of the lifting vertical plate, the third driving device is fixedly installed at the placing gap, an output shaft of the third driving device extends forward and is connected with the gear, and the gear is meshed with the rack.

[0025] Further, the welding gun fixing mechanism comprises a T-shaped fixing column, a lifting base, a fine adjustment lifting table, a fourth driving mechanism and a contact type displacement sensor. One side of the T-shaped fixing column is fixedly connected with the fixing frame. The fine adjustment lifting table is slidably connected with the lifting base through a linear guide rail assembly. The fourth driving mechanism is fixedly installed at the top of the lifting base, a precision lead screw connected with the output end of the fourth driving mechanism forms a transmission pair with a nut arranged on the fine adjustment lifting table, and the fourth driving mechanism is used for driving the fine adjustment lifting table to perform precise displacement in the vertical direction. The welding gun and the contact type displacement sensor are fixedly installed side by side on the fine adjustment lifting table, and the detection direction of the contact type displacement sensor and the nozzle of the welding gun are both perpendicular to the axis direction of the ductile iron pipe.

[0026] Further, the welding smoke collecting device comprises a positioning plate, a horn-shaped dust collecting cover, a corrugated pipe and a dust collector. The positioning plate is installed on the other side of the fixing frame relative to the wire feeder. A collecting hole is formed in the positioning plate, the horn-shaped dust collecting cover is installed at the collecting hole, and the large-diameter end of the horn-shaped dust collecting cover faces the welding operation point. The small-diameter end of the horn-shaped dust collecting cover is connected in communication with the air inlet of the dust collector through the corrugated pipe.

[0027] Furthermore, a high-temperature resistant flexible enclosure is provided around the fixed frame; the high-temperature resistant flexible enclosure forms a semi-enclosed collection space around the working area of ​​the welding torch, and the opening of the horn-shaped dust suction hood is located at the top of this collection space.

[0028] Furthermore, it also includes a limiting and guiding mechanism, which is connected to the welding power source; The limiting and guiding mechanism includes a concave bracket, a copper grounding braid, a counterweight, and a rotation limiting block; The concave bracket is positioned across the bottom of the pipe rotation mechanism, with the copper grounding braid mounted on its top. The copper grounding braid is a soft braided conductive material, with its middle section hanging down naturally to support the body of the ductile iron pipe. One end of the copper grounding braid is connected to the concave bracket, and the other end extends downward and passes around a rotating roller before being connected to the counterweight. This connection structure ensures that the copper grounding braid remains taut under the action of the counterweight and is in close contact with the bottom surface of the tube. The end of the copper grounding braid is connected to the negative cable of the welding power source via a conductive clamp. A vertical support frame is fixed to the side of the concave bracket, and the rotation limiting block is installed on its top via a bearing; the working surface of the rotation limiting block is set to be lower than the central axis of the ductile iron pipe, and is used to abut against the end face of the bottom of the ductile iron pipe to achieve axial limiting during the welding process.

[0029] 3. Beneficial effects: Compared with the prior art, the technical solution provided by this invention has the following advantages: This invention features a rational design that, through integrated electromechanical design, primarily addresses the bottlenecks in production efficiency and automation. The device can be directly integrated into existing production lines, achieving online automation of ductile iron pipe ring welding and completely freeing workers from arduous manual welding. Its pipe rotation mechanism employs a central synchronous drive, ensuring uniform and stable pipe rotation, while the welding torch achieves rapid positioning through a high-precision lifting and lateral movement mechanism, significantly reducing auxiliary time and resulting in a continuous and efficient production cycle, greatly improving overall operational efficiency.

[0030] In terms of welding quality, this device represents a revolutionary improvement. Its core lies in the introduction of a closed-loop height tracking control system based on a contact-type displacement sensor. This system can sense and dynamically compensate for the ellipticity and local deformation of the pipe wall in real time, ensuring that the welding wire extending from the welding torch nozzle maintains a constant, optimal working distance. This not only guarantees uniform weld penetration and consistent weld formation throughout the entire circumference, effectively eliminating quality defects such as incomplete penetration and undercut, but also frees welding quality from dependence on the individual skills and experience of the operator, achieving stable and replicable high-quality welding.

[0031] In addition, the device has excellent environmental friendliness and operation safety. The integrated welding dust collecting device, combined with the flexible dust hood and semi-closed fence, can realize efficient source capture before the dust spreads, significantly improving the working environment. At the same time, the device itself is provided with reliable mechanical limiting and stroke protection, avoiding the risk of overtravel operation. The characteristics of high automation, high quality and environmental safety greatly reduce the comprehensive operation cost, and provide advanced equipment support for the upgrading of ductile cast iron pipe industry.

[0032] It should be noted that the structures not introduced in the present application do not involve the design points and improvement direction of the present application, and are the same as or can be realized by using the prior art, and are not described here. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic diagram of the present application; Figure 2 is a second angle structural schematic diagram of the present application; Figure 3 is a structural schematic diagram of the lifting support frame of the present application; Figure 4 is another angle structural schematic diagram of the lifting support frame of the present application; Figure 5 is a structural schematic diagram of the pipeline rotating mechanism and fixing frame of the present application; Figure 6 is an enlarged structural schematic diagram of A of the present application; Figure 5 Figure 7 is another angle structural schematic diagram of the pipeline rotating mechanism and fixing frame of the present application; Figure 8 is an enlarged structural schematic diagram of B of the present application; Figure 7 Figure 9 is a side structural schematic diagram of the present application; Figure 10 is a structural schematic diagram of the welding dust collecting device of the present application; Figure 11 is a third angle structural schematic diagram of the present application; Figure 12 is a structural schematic diagram of the limiting flow guide mechanism of the present application.

[0034] Reference signs: ​​1, pipeline conveying mechanism; 2, pipeline rotating mechanism; 21, door type support seat; 211, back-shaped frame structure; 212, mounting hole; 213, fixed block; 214, concave positioning block; 22, supporting roller; 23, first sprocket; 24, rotating shaft; 25, second sprocket; 3, lifting support frame; 31, fixed base; 32, supporting column; 321, lifting positioning track; 322, L-shaped fixed plate; 323, shielding plate; 324, travel switch; 33, fixed table; 34, second driving motor; 35, lifting vertical plate; 4, transverse moving mechanism; 41, transverse support plate; 42, supporting slide rail; 43, sliding positioning block; 44, rack; 45, gear; 46, third driving device; 47, right-angle positioning block; 5, fixed frame; 51, T-shaped fixed column; 52, lifting base; 53, fine adjustment lifting table; 54, fourth driving mechanism; 55, contact type displacement sensor; 6, wire feeder; 7, welding power supply; 8, gas feeding device; 9, welding smoke collecting device; 91, positioning plate; 92, horn-shaped dust collecting cover; 93, corrugated pipe; 94, dust collector; 95, collecting hole; 96, high-temperature-resistant flexible fence; 10, limiting flow guiding mechanism; 101, concave support; 102, copper grounding braid; 103, counterweight; 104, rotating limiting block; 105, vertical support frame. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present application, the present application will be described in more detail below with reference to the relevant drawings, which show several embodiments of the present application. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0036] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "page", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0037] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0038] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", "providing", "provided with" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] It should be noted that the structures not introduced in the present application do not involve the design key points and improvement direction of the present application, and can adopt the existing technology known by those skilled in the art.

[0040] The specific implementation of the present application is described in detail below in combination with specific embodiments.

[0041] Referring to the drawings Figures 1-12 A ductile cast iron pipe welding ring welding device, comprising A pipeline conveying mechanism 1 for conveying and positioning the ductile cast iron pipe; A pipeline rotating mechanism 2 arranged at the middle part of the two pipeline conveying mechanisms 1 for carrying and driving the ductile cast iron pipe to rotate around its own axis; A lifting support frame 3 arranged adjacent to the pipeline rotating mechanism 2; A transverse moving mechanism 4 mounted on the lifting support frame 3 and capable of vertically moving along it; A welding gun fixing mechanism connected to the end of the transverse moving mechanism 4 through a fixing frame 5, and the transverse moving mechanism 4 can drive the fixing frame 5 and the welding gun fixing mechanism to move forward and backward in the horizontal direction; A wire feeder 6 mounted on the fixing frame 5; A welding power supply 7 and a gas feeding device 8 arranged on the side of the lifting support frame 3, and the output ends thereof are connected to the wire feeder 6 and the welding gun fixing mechanism through high-temperature resistant pipelines; Wherein, the welding gun mounted on the welding gun fixing mechanism, the welding wire extending from the welding nozzle position of the welding gun can be adjusted and kept in close contact with the outer wall of the ductile cast iron pipe placed on the pipeline rotating mechanism 2; during welding, the pipeline rotating mechanism 2 drives the ductile cast iron pipe to rotate at a constant speed, while the wire feeder 6 feeds the wire, and the welding power supply 7 and the gas feeding device 8 work, so as to complete the automatic welding of continuous annular weld on the outer wall of the ductile cast iron pipe.

[0042] In the present embodiment, the pipeline conveying mechanism 1 is used to receive, support and convey the ductile cast iron pipe from the previous process. The mechanism is usually composed of two parallel arranged roller tracks, forming a conveying channel, and the length and spacing thereof can be adjusted according to the specifications of the pipe.

[0043] The pipe rotating mechanism 2 is embedded in the middle of the pipe conveying mechanism 1. The ductile iron pipe can be conveyed by a crane or a forklift. When the ductile iron pipe is conveyed to the position, the pipe rotating mechanism 2 is started to reliably clamp and drive the ductile iron pipe to rotate at a uniform speed around its own center axis by friction.

[0044] The lifting support frame 3 is fixedly installed on the production line foundation and located on one side of the pipe conveying mechanism 1. Its structure adopts a solid steel frame, and the side can be integrated with a control cabinet. The welding power supply 7 and the gas supply device 8, including argon / carbon dioxide mixed gas cylinders and pressure reducing valves, are centrally arranged behind the side of the lifting support frame 3, which is convenient for centralized management and maintenance.

[0045] The transverse moving mechanism 4 is installed on the front of the lifting support frame 3 through a sliding block or a guide rail. The entire transverse moving mechanism 4 is lifted in the vertical direction. Through the switch control of the side control cabinet, the welding height can be accurately set, so that the ductile iron pipe of various diameters can be easily adapted, and it is ensured that the welding wire extending from the welding nozzle of the welding gun can always align with the highest point of the pipe, that is, the predetermined position of the outer ring seam.

[0046] The fixed frame 5 is rigidly connected to the front end of the transverse moving mechanism 4. The transverse moving mechanism 4 itself also has a horizontal moving function, so that the fixed frame 5 can be driven to move in the direction of the pipe axis, that is, the front and back directions.

[0047] The wire feeder 6 is fixedly installed on one side of the fixed frame 5, which contains a wire feeding wheel and a pressing mechanism to continuously and stably push the welding wire out of the welding wire reel. The welding gun fixing mechanism is installed on the other side of the fixed frame 5 opposite to the wire feeder 6, which firmly locks the welding gun in the best welding posture. The welding wire extending from the welding nozzle of the welding gun is adjusted to gently contact or maintain a constant small distance with the outer wall of the ductile iron pipe.

[0048] The output cables of the welding power supply 7, the gas pipes of the gas supply device 8, and the wire feeding hose of the wire feeder 6 are bundled together, wrapped with a high-temperature-resistant corrugated pipe or a winding pipe for protection, pass through the wire feeder 6, and finally connected to the welding gun to provide energy, protective gas, and filler material for it.

[0049] The working process of the device is as follows: Firstly, a ductile iron pipe is moved to the working position by the pipe conveying mechanism 1 or hoisting equipment, and one end of the pipe is suspended above the pipe rotating mechanism 2. Then, the operator controls the side control cabinet: firstly, the transverse moving mechanism 4 is controlled to lift, so that the welding gun is approximately at the height corresponding to the pipe diameter; secondly, the horizontal moving mechanism is controlled, so that the welding gun is at the axial position required by the pipe end; finally, the welding wire extended from the welding gun is perfectly matched with the predetermined welding point on the pipe wall.

[0050] After the positioning is completed, the full-automatic welding program is started. The pipe rotating mechanism 2 is firstly started to drive the ductile iron pipe to rotate at a constant speed matched with the welding process. Then, the welding power supply 7 is powered on, the gas feeding device 8 feeds the protective gas, the wire feeder 6 starts to push the welding wire, the welding gun is successfully ignited, and the welding is started. Since the pipe continuously rotates, the welding wire extended from the welding gun can melt on the outer surface of the pipe to form a continuous, uniform and well-sealed annular weld.

[0051] After the welding is completed, the functional units are sequentially stopped, the pipe rotating mechanism 2 is stopped, the welding head is lifted and returned to the original position. The welded pipe can be conveyed to the next process by the conveying mechanism, so that a complete working cycle is completed.

[0052] In summary, the present application solves the problems of unstable quality of traditional manual welding and low integration and long auxiliary time of special ring welding machine by ingenious mechatronic design. The device can be directly embedded into the existing production line to realize online and automatic welding, greatly improve the production efficiency and the uniformity of product quality, and reduce the labor intensity and skill requirement of the operator.

[0053] Please refer to Figure 5 and Figure 7, the pipe rotating mechanism 2 comprises two symmetrical door type support seats 21, and two groups of support rollers 22 are rotatably installed on the top of each door type support seat 21; the outer end of the rotating shaft of the support roller 22 is respectively provided with a first sprocket 23, and the two first sprockets 23 on the same door type support seat 21 are located in different vertical planes; the bottom of the door type support seat 21 is further provided with a rotating shaft 24 driven by a first driving motor, and four second sprockets 25 are correspondingly installed on the rotating shaft 24; the first sprocket 23 and the second sprocket 25 in the same vertical plane are connected through a transmission chain; the first driving motor is a double-output shaft motor, and the output shafts at both ends thereof are connected to the rotating shafts 24 on the two door type support seats 21 through couplings, and in the embodiment, the two solid door type support seats 21 are symmetrically and fixedly installed in the middle of the two pipe conveying mechanisms 1. Two groups of support rollers 22 are parallelly installed on the top beam of each door type support seat 21 through a bearing seat. The two groups of support rollers 22 jointly form a V-shaped or U-shaped supporting unit for stably supporting the ductile iron pipe. One end of the rotating shaft of the support roller 22 extends to the outside of the door type support seat 21 and is respectively provided with a first sprocket 23. Importantly, the two first sprockets 23 on the same door type support seat 21 are arranged in different vertical planes, thereby providing independent running space for the two transmission chains and avoiding mutual interference.

[0054] At the bottom of each door type support seat 21, a rotating shaft 24 supported by a bearing is arranged. Two second sprockets 25 are fixedly installed on the two ends of the rotating shaft 24, and the positions thereof are accurately corresponding to the two first sprockets 23 in the vertical direction. A first sprocket 23 and a second sprocket 25 located in the same vertical plane are connected through a closed transmission chain.

[0055] The first driving motor is preferably a double-output shaft motor, which is installed at the center position between the two door type support seats 21. The output shafts at both ends thereof are respectively rigidly connected to the rotating shafts 24 on the left and right door type support seats 21 through couplings.

[0056] When the driving of the nodular cast iron pipe is needed, the double output shaft motor is started, and its output torque is transmitted to the rotating shaft 24 on the door type support seat 21 on both sides through the shaft coupling. The rotating shaft 24 drives the four second sprockets 25 on it to rotate synchronously, and the second sprocket 25 transmits power to the corresponding first sprocket 23 through the transmission chain, so as to drive the four supporting rollers 22 to rotate synchronously. Since the supporting rollers 22 are in direct contact with the outer wall of the nodular cast iron pipe, the nodular cast iron pipe can be effectively driven to rotate smoothly and uniformly around its own axis through friction, so as to provide ideal parent material movement conditions for the girth welding. In this embodiment, a single double-shaft motor is used to drive the center through a mechanical coupling, which fundamentally ensures the absolute synchronous rotation of the two supporting rollers 22, effectively avoids the pipe body from twisting, crawling or wearing due to the asynchronization of driving, and ensures the uniformity and stability of the pipe body speed during the welding process, which is a key prerequisite for obtaining high-quality girth welds.

[0057] Please refer to Figure 6 , the top of the door type support seat 21 is a back-shaped frame structure 211, a plurality of installation holes 212 are symmetrically arranged on the back-shaped frame structure 211 along the length direction; the supporting roller 22 is installed on the back-shaped frame through an assembled bearing seat, the assembled bearing seat includes a fixed block 213 and a concave positioning block 214; the fixed block 213 is selectively fixed on the installation hole 212 at different positions through a bolt; the concave positioning block 214 is connected to the top of the fixed block 213, and the combination part of the fixed block 213 and the concave positioning block 214 jointly forms a complete rotating hole, a bearing is installed in the rotating hole, and the rotating shaft of the supporting roller 22 is supported in the bearing. In this embodiment, when the nodular cast iron pipes with different diameters need to be adapted, the bolts on the fixed block 213 can be loosened, so that the entire assembled bearing seat, including the fixed block 213, the concave positioning block 214 and the supporting roller 22, can be slid along the installation hole 212 on the back-shaped frame to a new required position. After adjustment, the bolts are tightened again, so that the supporting roller 22 can be firmly locked at the new working position. This design makes the center distance between the two supporting rollers 22 flexible and accurate according to the outer diameter of the pipe. During the welding operation, the pipe is stably supported by the four supporting rollers 22 and is synchronously driven to rotate. In this embodiment, the flexible and reliable adjustment of the distance between the supporting rollers 22 is realized through the cooperation of the bolts and the series of installation holes 212. This makes a set of pipe rotating mechanism 2 capable of adapting to nodular cast iron pipes with various diameters within a certain size range, significantly improves the universality of the equipment, and reduces the equipment investment cost for different specifications of pipes.

[0058] Please refer to Figure 3 and Figure 4The lifting support frame 3 comprises a fixed base 31, a support column 32, a fixed table 33, a second driving motor 34, a rotating screw rod and a lifting vertical plate 35. The fixed base 31 is fixed to the ground by anchor bolts. The support column 32 is vertically arranged on the top of the fixed base 31. The fixed table 33 is connected to the top end of the support column 32. The second driving motor 34 is installed on the fixed table 33, and its output shaft extends vertically downward and is connected to the rotating screw rod. The rotating screw rod and the screw nut arranged on the back of the lifting vertical plate 35 form a threaded transmission pair. In this embodiment, the lifting support frame 3 is the core support structure of the carrying transverse moving mechanism 4 and the welding execution unit. The bottom of the lifting support frame 3 is the fixed base 31 with good rigidity, which is firmly fixed to the workshop foundation by the pre-buried anchor bolts, ensuring the stability of the whole device during operation. The support column 32 is vertically fixed to the fixed base 31, providing main height support. The top end of the support column 32 is connected to the fixed table 33 for installing the second driving motor 34. The second driving motor 34 is preferably a servo motor or a worm gear reduction motor with a brake function. Its output shaft extends vertically downward and is connected to a precision rotating screw rod through a shaft coupling. The back of the lifting vertical plate 35 is fixedly installed with a screw nut matched with the rotating screw rod. When the second driving motor 34 is powered on and rotates, it drives the rotating screw rod to rotate, thereby converting into the linear motion of the lifting vertical plate 35 in the vertical direction.

[0059] Please refer to Figure 3The two sides of the support column 32 are symmetrically provided with lifting positioning tracks 321; the lifting vertical plate 35 is slidably connected with the lifting positioning tracks 321 through L-shaped fixing plates 322, one side of the L-shaped fixing plates 322 is matched with the lifting positioning tracks 321 through sliding blocks, and the other side is fixedly connected with the side surface of the lifting vertical plate 35; the bottom outer side of the L-shaped fixing plates 322 is detachably provided with a shielding plate 323, and one row switch 324 is arranged at each of the upper and lower ends of the side surface of the lifting positioning tracks 321, and the triggering positions of the two row switches 324 correspond to the upper and lower limit positions of the shielding plate 323 when the lifting vertical plate 35 is lifted, in this embodiment, in order to ensure that the lifting process is stable, without shaking and accurate guiding, the lifting positioning tracks 321 are symmetrically arranged at the two sides of the support column 32, for example, high-precision linear guides are adopted. The lifting vertical plate 35 is not directly connected with the guide rail, but is transitionally connected through the L-shaped fixing plates 322. One side of the L-shaped fixing plates 322 is matched with the lifting positioning tracks 321 through sliding blocks such as sliding block bearings, and the other side is fixedly connected with the side surface of the lifting vertical plate 35. This symmetrical double-track guiding structure can effectively resist the overturning moment generated by the transverse moving mechanism 4 and the forward extension of the welding gun, and ensure the rigidity and precision of the lifting movement. For safety protection, in order to prevent the lifting mechanism from running beyond the mechanical limit position, one row switch 324 is arranged at each of the highest point and the lowest point positions of the lifting vertical plate 35 on the side surface of the lifting positioning tracks 321. A detachable shielding plate 323 is arranged on the bottom outer side of the L-shaped fixing plate 322. When the lifting vertical plate 35 drives the L-shaped fixing plate 322 and the shielding plate 323 to move up and down, the shielding plate 323 will touch the corresponding row switch 324 when reaching the limit position, and the row switch 324 will immediately send a signal to the control system to cut off the power of the second driving motor 34 or make it stop running, thereby realizing hard limit protection. When the welding height needs to be adjusted, the control system instructs the second driving motor 34 to start to drive the rotating screw to rotate. The nut meshing with the screw drives the lifting vertical plate 35 and the entire transverse moving mechanism 4 and the welding head connected therewith to stably rise or fall along the lifting positioning tracks 321. The guide rail ensures that the movement trajectory is straight without deviation. When the lifting reaches the preset height or the shielding plate 323 triggers any row switch 324, the motor stops, the lifting action is completed, and the device is locked at the current height for welding work.

[0060] Please refer to Figure 3 and Figure 4The lateral moving mechanism 4 comprises a lateral support plate 41, support sliding rails 42, sliding positioning blocks 43, a rack 44, a gear 45 and a third driving device 46; the lateral support plate 41 is connected with the lifting vertical plate 35 through the support sliding rails 42 fixed on both sides of the lateral support plate 41; the right-angle positioning blocks 47 symmetrically arranged are fixed on the front surface of the lifting vertical plate 35; the sliding positioning blocks 43 are installed on the right-angle positioning blocks 47, and the sliding positioning blocks 43 and the support sliding rails 42 form a sliding pair; the rack 44 is fixedly installed on the bottom of the lateral support plate 41; a placing gap is formed on the rear side of the lifting vertical plate 35, and the third driving device 46 is fixedly installed in the placing gap; the output shaft of the third driving device 46 extends forward and is connected with the gear 45; the gear 45 is engaged with the rack 44; in this embodiment, the lateral moving mechanism 4 is used to realize the accurate displacement adjustment of the welding torch along the pipeline axis direction; the core transmission components adopt the engagement mode of the gear 45 and the rack 44; specifically, the rack 44 is fixedly installed on the bottom of the lateral support plate 41 along the horizontal direction; a placing gap is formed on the rear side of the lifting vertical plate 35; the third driving device 46 is usually a servo motor or a stepping motor, and is fixedly installed in the gap; the output shaft of the third driving device 46 penetrates through the lifting vertical plate 35 forwardly, and the gear 45 is installed at the end of the output shaft; the gear 45 is in precise engagement with the rack 44; in order to ensure the stability and the guiding accuracy during the moving process, the right-angle positioning blocks 47 are symmetrically fixed on the front surface of the lifting vertical plate 35; the sliding positioning blocks 43 are installed on each right-angle positioning block 47; the support sliding rails 42 matched with the sliding positioning blocks 43 are fixedly installed on both sides of the lateral support plate 41; the sliding positioning blocks 43 and the support sliding rails 42 form a high-rigidity linear guide pair.

[0061] Please refer to Figure 7 and Figure 8 The welding torch fixing mechanism comprises a T-shaped fixing column 51, a lifting base 52, a fine adjustment lifting platform 53, a fourth driving mechanism 54 and a contact type displacement sensor 55. The T-shaped fixing column 51 is fixedly connected with one side of the fixing frame 5. The fine adjustment lifting platform 53 is slidably connected with the lifting base 52 through a linear guide rail assembly. The fourth driving mechanism 54 is fixedly installed on the top of the lifting base 52; the precision screw rod connected with the output end of the fourth driving mechanism 54 and the nut arranged on the fine adjustment lifting platform 53 form a transmission pair, and are used to drive the fine adjustment lifting platform 53 to perform the precise displacement in the vertical direction. The welding torch and the contact type displacement sensor 55 are fixedly installed side by side on the fine adjustment lifting platform 53; the detection direction of the contact type displacement sensor 55 and the nozzle of the welding torch are both perpendicular to the axis direction of the ductile iron pipe. In the embodiment, the signal output end of the contact displacement sensor 55 is connected to a control unit, and the control output end of the control unit is electrically connected with the fourth driving mechanism 54, thereby constituting a closed-loop height tracking control system. The contact displacement sensor 55 and the wall of the ductile iron pipe are in contact and expansion, so as to control the lifting of the fine adjustment lifting platform 53, and the distance between the welding wire of the welding torch and the ductile iron pipe is kept consistent at all times, thereby improving the quality of the welding ring; The height tracking control system of the present application can be realized by using the prior art, and the specific implementation is as follows: Signal detection: when the welding starts, the ductile iron pipe is driven to rotate at a constant speed by the rotating mechanism. The probe of the contact displacement sensor 55 is in contact with the pipe wall at all times, and the prior art can be used. In the embodiment, the contact displacement sensor 55 adopting the LVDT principle or the resistance principle is used. When the pipe wall is not round or deformed and generates radial runout, the probe is pushed to expand and contract, and the inside of the sensor converts the linear displacement into proportional electrical signal analog voltage / current or digital signal real-time output; Signal processing and decision: the electrical signal is transmitted to the control unit, such as a PLC or a special motion controller. The control unit compares the received real-time displacement signal with a preset “reference value”, which is the sensor reading corresponding to the ideal, non-deformed round pipe wall, and calculates the deviation between the two.

[0062] The control unit generates corresponding correction instructions, such as a PID algorithm, according to the size and direction of the deviation, and drives the fourth driving mechanism 54 to act. In the embodiment, a servo motor is used. The motor rotates and drives the entire fine adjustment lifting platform 53, the welding torch and the sensor to perform a fine lifting movement together through a precision screw-nut pair. The specific process is as follows: when the pipe wall is concave, the sensor probe is retracted, the reading is less than the reference value, the control unit sends a command to the motor to drive the welding torch to move downward to track the concave. When the pipe wall is convex, the sensor probe is pushed outward, the reading is greater than the reference value, and the control unit sends a command to the motor to drive the welding torch to move upward to avoid the convex. Through the dynamic setting of the embodiment, the constant arc length and heat input are maintained, the penetration and width of the entire circumferential weld are uniform, the defects such as incomplete penetration, undercut and welding tumor caused by pipe shape error are fundamentally avoided, the welding height is self-adaptively adjusted, manual intervention is not required, the dependence on the experience of operators is reduced, and the production automation level and efficiency are improved.

[0063] Please refer to Figure 10 It also comprises a welding smoke collecting device 9; the welding smoke collecting device 9 comprises a positioning plate 91, a horn-shaped dust collecting cover 92, a corrugated pipe 93 and a dust collector 94; The positioning plate 91 is installed on the other side of the fixed frame 5 relative to the wire feeder 6. The positioning plate 91 has a collection hole 95, and the horn-shaped dust suction hood 92 is installed at the collection hole 95, with its large diameter end facing the welding operation point. The small-diameter end of the horn-shaped dust hood 92 is connected to the air inlet of the dust collector 94 via the corrugated pipe 93. In this embodiment, the horn-shaped dust hood 92 is installed on the collection hole 95, and the bottom of its large-diameter opening is the working position of the welding torch and the pipe wall to maximize the smoke capture range. The outlet of the horn-shaped dust hood 92 is connected to one end of a corrugated pipe 93. The corrugated pipe 93 is flexible and not easily crushed. It can have a metal spiral support frame embedded inside to maintain the ventilation cross section, and the outside is made of a high-temperature resistant flexible material. The other end of the corrugated pipe 93 is connected to the dust collector 94. The dust collector 94 is a standard industrial device in the prior art, such as a bag filter or electrostatic precipitator, which can generate negative pressure suction and filter and purify the sucked-in smoke and dust. The dust collector 94 is started before or simultaneously with the welding process. The negative pressure suction generated by the dust collector 94 is transmitted to the horn-shaped dust hood 92 through the corrugated pipe 93, forming a stable directional airflow field at the hood opening.

[0064] When welding begins, the large amount of welding fumes generated will be effectively captured by the directional airflow as they rise and diffuse. They will then be drawn into the dust collector 94 for purification via the horn-shaped dust hood 92 and the corrugated pipe 93.

[0065] Due to its excellent flexibility, the corrugated pipe 93 can be flexibly adjusted in direction and length according to the site layout to avoid interference with other equipment components. In addition, the middle section of the corrugated pipe 93 can be suspended from the workshop ceiling by additional suspension devices such as slings to reduce the load on the fixing frame 5 and to more accurately fix the orientation of the horn-shaped dust hood 92, ensuring that it is always efficiently aligned with the welding points.

[0066] Please refer to this carefully. Figure 1 and Figure 10 The fixing frame 5 is surrounded by a high-temperature resistant flexible enclosure 96. This enclosure 96 forms a semi-enclosed collection space around the welding torch's working area. The vent of the horn-shaped dust extraction hood 92 is located at the top of this collection space. In this embodiment, during welding operations, the welding fumes mainly rise and diffuse upwards. The collection space formed by the high-temperature resistant flexible enclosure 96 effectively prevents fumes from dissipating over a large area, confining most of the fumes to a relatively small area.

[0067] Due to the constraint of the enclosure, the rising smoke and dust are more likely to concentrate and converge towards the funnel-shaped dust collection hood 92 located at the top of the space, where they are efficiently sucked in by the negative pressure airflow.

[0068] This structure significantly reduces the emission of smoke dust, greatly improves the capture rate and collection efficiency of smoke dust under the same suction of the vacuum cleaner, and further improves the working environment.

[0069] Further comprising a limiting flow guide mechanism 10, which is connected with the welding power supply 7; The limiting flow guide mechanism 10 comprises a concave bracket 101, a copper grounding braid 102, a counterweight 103, and a rotating limiting block 104; The concave bracket 101 is arranged horizontally below the pipeline rotating mechanism 2, and the top of the concave bracket 101 is provided with the copper grounding braid 102; the copper grounding braid 102 is a soft braided conductor, and the middle part of the copper grounding braid 102 naturally droops and is used for supporting the pipe body of the ductile iron pipe; One end of the copper grounding braid 102 is connected with the concave bracket 101, and the other end of the copper grounding braid 102 extends downward, passes around a rotating roller, and is connected with the counterweight 103; the connection structure makes the copper grounding braid 102 always keep in a tension state under the action of the counterweight 103 and tightly contact with the bottom surface of the pipe body; The end of the copper grounding braid 102 is connected with the negative electrode cable of the welding power supply 7 through a conductive clamp; Please refer to Figure 11 With 12 A vertical support frame 105 is fixed to the side surface of the concave bracket 101, and the rotating limiting block 104 is installed on the top of the vertical support frame 105 through a bearing; the working surface of the rotating limiting block 104 is arranged to be lower than the central axis of the ductile iron pipe, and is used for abutting against the end surface of the bottom of the ductile iron pipe to realize axial limiting during the welding process; in this embodiment, the middle segment of the copper grounding braid 102 naturally droops under the action of gravity to form an arc-shaped supporting surface. When the ductile iron pipe is placed on the pipeline rotating mechanism 2, the pipe body of the ductile iron pipe is placed on the arc-shaped copper grounding braid 102. One end of the copper grounding braid 102 is fixed, and the other end of the copper grounding braid 102 extends downward, passes around a rotating roller, and is connected with a counterweight 103. The counterweight 103 provides a continuous upward tension force for the copper grounding braid 102 through a pulley mechanism, so as to ensure that the copper grounding braid 102 can adaptively and tightly contact with the pipe wall bottom surface regardless of the change of the pipe diameter, and form stable electrical contact.

[0070] During the welding, the positive electrode of the welding power supply 7 is connected with the to-be-welded area of the upper part of the pipe body through the welding wire of the welding gun, and the negative electrode is connected with the conductive clamp through the cable, and the conductive clamp is fixed to the end of the copper grounding braid 102. In this way, the current forms a complete welding loop from the welding gun→welding wire→pipe body→copper grounding braid 102→power supply. This flexible contact mode avoids damage to the surface of the pipe body caused by rigid striking, and ensures the stability of the current loop; A vertical support frame 105 is fixed on the side of the concave support 101, and a rotatable limiting block 104 such as a nylon or copper roller is mounted on the top of the vertical support frame 105 through a bearing. The installation height of the rotatable limiting block 104 is accurately calculated so that the working surface of the rotatable limiting block 104 is slightly lower than the horizontal center axis of the nodular cast iron pipe. When the pipe body is positioned on the rotating mechanism, the inner wall or end face of the pipe end will lightly abut against the rotatable limiting block 104. During the welding process, the pipe rotating mechanism 2 drives the pipe body to rotate. Since the rotatable limiting block 104 is mounted through a bearing, it will rotate with the pipe end due to friction, so that the axial limiting of the pipe body is changed from sliding friction to rolling friction, and the resistance is extremely small. This effectively prevents the axial movement of the pipe body during rotation due to vibration or uneven driving force, ensures the accuracy and consistency of the axial position of the welding ring weld, and avoids the additional power loss or pipe end wear caused by limiting.

[0071] The above-described embodiments only express some implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A welding device for welded rings on ductile iron pipes, characterized in that: include Pipeline conveying mechanism (1) conveys and positions ductile iron pipes; The pipe rotation mechanism (2) is located in the middle of the two pipe conveying mechanisms (1) and is used to carry and drive the ductile iron pipe to rotate around its own axis. A lifting support frame (3) is provided adjacent to the pipe rotation mechanism (2); A lateral moving mechanism (4) is installed on the lifting support frame (3) and can move vertically along it; The welding torch fixing mechanism is connected to the end of the transverse moving mechanism (4) via a fixing frame (5). The transverse moving mechanism (4) can drive the fixing frame (5) and the welding torch fixing mechanism to move back and forth in the horizontal direction. The wire feeder (6) is mounted on the fixed frame (5); The welding power source (7) and the gas supply device (8) are located on the side of the lifting support frame (3), and their output ends are connected to the wire feeder (6) and the welding gun fixing mechanism through high temperature resistant pipelines. The welding torch installed on the welding torch fixing mechanism has a welding wire extending from the welding nozzle that can be adjusted and kept in contact with the outer wall of the ductile iron pipe placed on the pipe rotating mechanism (2). During welding, the pipe rotating mechanism (2) drives the ductile iron pipe to rotate at a constant speed, while the wire feeder (6) feeds the wire, and the welding power source (7) and the gas supply device (8) work, thereby completing the automated welding of a continuous annular weld on the outer wall of the ductile iron pipe.

2. The welding device for welded rings on ductile iron pipes according to claim 1, characterized in that: The pipe rotation mechanism (2) includes two symmetrically arranged portal support seats (21), and two sets of support rollers (22) are rotatably mounted on the top of each portal support seat (21); a first sprocket (23) is respectively installed on the outer end of the rotating shaft of the support roller (22), and the two first sprockets (23) on the same portal support seat (21) are in different vertical planes; a rotating shaft (24) driven by a first drive motor is also provided at the bottom of the portal support seat (21), and four second sprockets (25) are correspondingly installed on the rotating shaft (24); the first sprockets (23) and the second sprockets (25) in the same vertical plane are connected by a transmission chain; the first drive motor is a dual-output shaft motor, and the output shafts at both ends are respectively connected to the rotating shafts (24) on the two portal support seats (21) through couplings.

3. The welding device for welded rings of ductile iron pipes according to claim 2, characterized in that: The top of the portal support (21) is a U-shaped frame structure (211), and a plurality of spaced mounting holes (212) are symmetrically distributed along its length. The support roller (22) is mounted on the U-shaped frame through an assembled bearing seat, which includes a fixing block (213) and a concave positioning block (214). The fixing block (213) is selectively fixed to the mounting holes (212) at different positions by bolts. The concave positioning block (214) is connected to the top of the fixing block (213), and the joint of the fixing block (213) and the concave positioning block (214) together form a complete rotating hole. A bearing is installed in the rotating hole, and the shaft of the support roller (22) is supported in the bearing.

4. The welding device for welded rings on ductile iron pipes according to claim 1, characterized in that: The lifting support frame (3) includes a fixed base (31), a support column (32), a fixed platform (33), a second drive motor (34), a rotating screw, and a lifting vertical plate (35). The fixed base (31) is fixed to the ground by anchor bolts. The support column (32) is vertically erected on the top of the fixed base (31). The fixed platform (33) is connected to the top of the support column (32). The second drive motor (34) is installed on the fixed platform (33), and its output shaft extends vertically downward and is connected to the rotating screw. The rotating screw and the screw nut provided on the back of the lifting vertical plate (35) form a threaded transmission pair.

5. The welding device for welded rings on ductile iron pipes according to claim 4, characterized in that: The supporting column (32) is symmetrically provided with lifting and positioning rails (321) on both sides; the lifting vertical plate (35) is slidably connected to the lifting and positioning rails (321) through an L-shaped fixing plate (322), one side of the L-shaped fixing plate (322) cooperates with the lifting and positioning rails (321) through a sliding block, and the other side is fixedly connected to the side of the lifting vertical plate (35); a baffle plate (323) is detachably installed on the bottom outer side of the L-shaped fixing plate (322), and a limit switch (324) is provided at each of the upper and lower ends of the side of the lifting and positioning rail (321). The triggering positions of the two limit switches (324) correspond to the upper and lower limit positions of the baffle plate (323) when it rises and falls with the lifting vertical plate (35).

6. The welding device for welded rings of ductile iron pipes according to claim 5, characterized in that: The lateral moving mechanism (4) includes a lateral support plate (41), a support slide rail (42), a sliding positioning block (43), a rack (44), a gear (45), and a third driving device (46). The lateral support plate (41) is connected to the lifting vertical plate (35) through the support slide rail (42) fixed on both sides. The right-angle positioning blocks (47) are symmetrically arranged and fixed on the front surface of the lifting vertical plate (35). The sliding positioning block (43) is installed on the right-angle positioning block (47), and the sliding positioning block (43) and the support slide rail (42) form a sliding pair. The rack (44) is fixedly installed on the bottom of the lateral support plate (41). The lifting vertical plate (35) has a placement notch on its rear side. The third driving device (46) is fixedly installed at the placement notch, and its output shaft extends forward and connects to the gear (45). The gear (45) meshes with the rack (44).

7. The welding device for welded rings on ductile iron pipes according to claim 1, characterized in that: The welding torch fixing mechanism includes a T-shaped fixing column (51), a lifting base (52), a fine-tuning lifting platform (53), a fourth drive mechanism (54), and a contact displacement sensor (55). The T-shaped fixing column (51) is fixedly connected to one side of the fixing frame (5); The fine-tuning lifting platform (53) is slidably connected to the lifting base (52) through a linear guide rail assembly; The fourth drive mechanism (54) is fixedly installed on the top of the lifting base (52). The precision lead screw connected to its output end and the nut set on the fine-tuning lifting platform (53) form a transmission pair, which is used to drive the fine-tuning lifting platform (53) to make a precise vertical displacement. The welding torch and the contact displacement sensor (55) are fixedly installed side by side on the fine-tuning lifting platform (53), and the detection direction of the contact displacement sensor (55) and the nozzle of the welding torch are both perpendicular to the axial direction of the ductile iron pipe.

8. The welding device for welded rings of ductile iron pipes according to claim 1, characterized in that: It also includes a welding fume collection device (9); the welding fume collection device (9) includes a positioning plate (91), a horn-shaped dust suction hood (92), a corrugated pipe (93), and a dust collector (94); The positioning plate (91) is installed on the other side of the fixing frame (5) relative to the wire feeder (6); The positioning plate (91) has a collection hole (95), and the horn-shaped dust suction hood (92) is installed at the collection hole (95), with its large diameter end facing the welding operation point; The small-diameter end of the horn-shaped dust hood (92) is connected to the air inlet of the dust collector (94) through the corrugated pipe (93).

9. The welding device for welded rings on ductile iron pipes according to claim 8, characterized in that: The fixed frame (5) is surrounded by a high-temperature resistant flexible enclosure (96); the high-temperature resistant flexible enclosure (96) forms a semi-enclosed collection space around the working area of ​​the welding torch, and the opening of the horn-shaped dust suction hood (92) is located at the top of the collection space.

10. The welding device for welded rings of ductile iron pipes according to claim 1, characterized in that: It also includes a limiting and guiding mechanism (10), which is connected to the welding power source (7); The limiting and guiding mechanism (10) includes a concave bracket (101), a copper grounding braid (102), a counterweight (103), and a rotation limiting block (104). The concave bracket (101) is positioned across the bottom of the pipe rotating mechanism (2), and the copper grounding braid (102) is mounted on its top. The copper grounding braid (102) is a soft braided conductive material, with its middle section hanging down naturally and used to support the body of the ductile iron pipe. One end of the copper grounding braid (102) is connected to the concave bracket (101), and the other end extends downward and passes around a rotating roller before being connected to the counterweight (103). Under the action of the counterweight (103), the copper grounding braid (102) always remains taut and in close contact with the bottom surface of the tube. The end of the copper grounding braid (102) is connected to the negative cable of the welding power source (7) via a conductive clamp; A vertical support frame (105) is fixed to the side of the concave bracket (101), and the top of the frame is equipped with the rotation limit block (104) via a bearing. The working surface of the rotation limit block (104) is set to be lower than the central axis of the ductile iron pipe, and is used to abut against the end face of the bottom of the ductile iron pipe to achieve axial positioning during the welding process.

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