A ductile cast iron pipe welding ring welding device

Abstract

The application provides a ductile cast iron pipeline welding ring welding device, and relates to the technical field of ductile cast iron pipeline welding. The device 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 a gas feeding device. The pipeline rotating mechanism is arranged in the middle of the conveying mechanism to drive the pipeline body to rotate at a constant speed. The transverse moving mechanism on the side of the lifting support frame can drive the welding gun to accurately displace vertically and horizontally. The welding gun fixing mechanism is installed on the fixing frame and has a fine adjustment function to ensure a constant distance between the welding nozzle and the pipeline wall. The welding power supply and the gas feeding device provide energy and protective gas for welding through pipelines. Optionally, a welding smoke collecting device and a high-temperature resistant fence can also be integrated. The application realizes online automation of welding ring operation, effectively improves welding efficiency, quality stability and operation environment friendliness.

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:

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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

[0008] 1. The technical problem to be solved by the present application:

[0009] The present application provides a ductile cast iron pipe welding ring welding device to solve the technical problems in the background art.

[0010] 2. Technical solution:

[0011] To achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows: a ductile cast iron pipe welding ring welding device, comprising a pipeline conveying mechanism for conveying and positioning the ductile cast iron pipe;

[0012] A pipeline rotating mechanism is arranged in the middle part of the two pipeline conveying mechanisms and is used to carry and drive the ductile cast iron pipe to rotate around its own axis.

[0013] A lifting support frame is arranged adjacent to the pipeline rotating mechanism.

[0014] A transverse moving mechanism is installed on the lifting support frame and can move vertically along it.

[0015] 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.

[0016] A wire feeder is installed on the fixing frame.

[0017] A welding power supply and a gas feeding device are arranged on the side of the lifting support frame, and their output ends are connected to the wire feeder and the welding gun fixing mechanism through high-temperature resistant pipelines.

[0018] The welding gun installed on the welding gun fixing mechanism, and 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. During welding, the pipeline rotating mechanism drives the ductile cast iron pipe to rotate at a constant speed, while the wire feeder feeds the wire, and the welding power supply and the gas feeding device work, thereby completing the automatic welding of continuous annular welds on the outer wall of the ductile cast iron pipe.

[0019] The pipeline conveying mechanism described in the present application 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 beds, forming a conveying channel, the length and spacing of which can be adjusted according to the specifications of the pipe.

[0020] The pipeline rotating mechanism is embeddedly arranged in the middle part of the pipeline conveying mechanism. The ductile cast iron pipe can be conveyed by a travelling crane or a forklift. When the ductile cast iron pipe is conveyed into position, the pipeline rotating mechanism is started, and the ductile cast iron pipe is reliably clamped and driven to rotate at a constant speed around its own central axis by friction.

[0021] The lifting support frame is fixedly installed on the foundation of the production line and located at 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 centrally arranged at the rear side of the lifting support frame, facilitating centralized management and maintenance.

[0022] The transverse moving mechanism is installed on the front surface of the lifting support frame through a sliding block or a guide rail. The entire transverse moving mechanism is vertically lifted. The welding height can be accurately set through the switch control of the side control cabinet, so that various diameter ductile iron pipes can be easily adapted, and it is ensured that the welding wire extending from the welding nozzle of the welding torch can always align with the highest point of the pipeline, i.e., the predetermined position of the outer ring seam.

[0023] The fixing frame is rigidly connected to the front end of the transverse moving mechanism. The transverse moving mechanism itself also has a horizontal moving function, so that the fixing frame can be driven to move in the pipeline axis direction, i.e., the front and back direction.

[0024] The wire feeder is fixedly installed on one side of the fixing frame, 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 torch fixing mechanism is installed on the other side of the fixing frame opposite to the wire feeder, which firmly locks the welding torch in the optimal welding posture. The welding wire extending from the welding nozzle of the welding torch is adjusted to gently contact or maintain a constant small distance with the outer wall of the ductile iron pipe.

[0025] The output cable of the welding power supply, 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, passed through the wire feeder, and finally connected to the welding torch to provide energy, protective gas, and filler material for it.

[0026] The working process of the device is as follows:

[0027] Firstly, a ductile iron pipe is moved to the working position by the pipeline conveying mechanism or hoisting equipment, so that one end of the pipe extends above the pipeline rotating mechanism. Then, the operator controls the side control cabinet: firstly, controls the transverse moving mechanism to lift, so that the welding torch approximately reaches the height corresponding to the pipe diameter; secondly, controls the horizontal movement of the transverse moving mechanism, so that the welding torch reaches the required axial position of the pipe end; finally, the welding wire extending from the welding nozzle of the welding torch is finally perfectly matched with the predetermined welding point of the pipe wall.

[0028] After positioning, the full-automatic welding program is started. The pipe rotating mechanism is first started to drive the nodular cast iron pipe to rotate at a constant speed matching the welding process. Then, the welding power supply is powered on, the gas feeding device feeds the protective gas, the wire feeder starts to push the welding wire, the welding torch successfully initiates the arc, and the welding starts. Due to the continuous rotation of the pipe, the welding wire continuously extended inside the welding nozzle of the welding torch can be deposited on the outer surface of the pipe to form a continuous, uniform and well-sealed annular weld.

[0029] After welding, each functional unit is sequentially stopped, the pipe rotating mechanism is stopped, the welding head is lifted and returned to the original position. The welded pipe can be transported to the next process by the conveying mechanism, thereby completing a complete working cycle.

[0030] 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 through ingenious mechatronic design. The device can be directly embedded into the existing production line to realize online and automatic welding, greatly improving the production efficiency and uniformity of product quality, and reducing the labor intensity and skill requirements of the operator.

[0031] Further, the pipe rotating mechanism includes two symmetrical door-type support seats, and two groups of support rollers are rotatably installed on the top of each door-type support seat; first sprockets are respectively installed on the outer side ends of the rotating shafts of the support rollers, and the two first sprockets located on the same door-type support seat are in different vertical planes; a rotating shaft driven by a first driving motor is further arranged at the bottom of the door-type support seat, and four second sprockets are correspondingly installed on the rotating shaft; the first sprockets and the second sprockets in the same vertical plane are connected by 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 on both sides of the door-type support seat through couplings.

[0032] Further, the top of the door-type support seat is a meandering frame structure, a plurality of spaced installation holes are symmetrically formed on the meandering frame structure along the length direction thereof; the support rollers are installed on the meandering frame through an assembled bearing seat, the assembled bearing seat includes a fixed block and a concave positioning block; the fixed block is selectively fixed on the installation holes at different positions through bolts; the concave positioning block is connected to the top of the fixed block, and 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.

[0033] Further, the lifting support frame comprises a fixed base, a support column, a fixed table, a second driving motor, a rotating screw rod 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 screw rod, and the rotating screw rod and a screw nut arranged on the back of the lifting vertical plate form a threaded transmission pair.

[0034] Further, lifting positioning tracks are symmetrically arranged on the two sides of the support column, the lifting vertical plate is slidably connected to 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 of the L-shaped fixing plate is fixedly connected to the side surface of the lifting vertical plate, a shielding plate is detachably installed on the bottom outer side of the L-shaped fixing plate, and one travel 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 travel 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.

[0035] Further, the transverse moving mechanism comprises a transverse support plate, support sliding rails, sliding positioning blocks, a rack, a gear and a third driving device, the transverse support plate is connected to the lifting vertical plate through the support sliding rails fixed on the two sides of the transverse support plate, right-angle positioning blocks are symmetrically arranged 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 on the bottom of the transverse support plate, a placing gap is formed in the back side of the lifting vertical plate, the third driving device is fixedly installed at the placing gap, the output shaft of the third driving device extends forward and is connected to the gear, and the gear and the rack are meshed with each other.

[0036] 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.

[0037] One side of the T-shaped fixing column is fixedly connected to the fixed frame.

[0038] The fine adjustment lifting table is slidably connected to the lifting base through a linear guide rail assembly.

[0039] The fourth driving mechanism is fixedly installed on the top of the lifting base, a precision screw rod connected to the output end of the fourth driving mechanism and a nut arranged on the fine adjustment lifting table form a transmission pair, and the fourth driving mechanism is used for driving the fine adjustment lifting table to perform precise displacement in the vertical direction.

[0040] The welding torch and the contact displacement sensor are fixedly installed side by side on the fine adjustment lifting platform, and the detection direction of the contact displacement sensor and the nozzle of the welding torch are both perpendicular to the axial direction of the ductile iron pipe.

[0041] Further, the welding smoke collecting device is also included; the welding smoke collecting device includes a positioning plate, a horn-shaped dust collecting hood, a corrugated pipe and a dust collector;

[0042] The positioning plate is installed on the other side of the fixed frame relative to the wire feeder;

[0043] A collecting hole is formed in the positioning plate, and the horn-shaped dust collecting hood is installed at the collecting hole, with the large-diameter end of the horn-shaped dust collecting hood facing the welding operation point;

[0044] The small-diameter end of the horn-shaped dust collecting hood is connected to the air inlet of the dust collector through the corrugated pipe.

[0045] Further, a high-temperature-resistant flexible fence is arranged around the fixed frame; the high-temperature-resistant flexible fence forms a semi-closed collecting space around the operation area of the welding torch, and the opening of the horn-shaped dust collecting hood is located at the upper part of the collecting space.

[0046] Further, a limiting flow guide mechanism is also included, which is connected to the welding power supply;

[0047] The limiting flow guide mechanism includes a concave bracket, a copper grounding braid, a counterweight and a rotating limiting block;

[0048] The concave bracket is arranged horizontally below the pipeline rotating mechanism, and the copper grounding braid is arranged on the top of the concave bracket; the copper grounding braid is a soft braided conductor, and the middle part of the copper grounding braid naturally droops and is used to support the pipe body of the ductile iron pipe;

[0049] One end of the copper grounding braid is connected to the concave bracket, and the other end of the copper grounding braid extends downward, passes around a rotating roller and is connected to the counterweight; the connection structure makes the copper grounding braid always maintain a tension state under the action of the counterweight and tightly contact the bottom surface of the pipe body;

[0050] The end of the copper grounding braid is connected to the negative electrode cable of the welding power supply through a conductive clamp;

[0051] A vertical support frame is fixed to the side surface of the concave bracket, and the rotating limiting block is installed on the top of the vertical support frame through a bearing; the working surface of the rotating limiting block is arranged to be lower than the central axis of the ductile iron pipe, and is used to abut against the end surface of the bottom of the ductile iron pipe to realize axial limiting during the welding process.

[0052] 3. Beneficial effects:

[0053] Compared with the prior art, the technical scheme provided by the application has the following beneficial effects:

[0054] The application has reasonable design, and by means of integrated mechanical and electrical design, the bottleneck problem of production efficiency and automation degree is solved first. The device is directly embedded in the existing production line, realizes online automation of the welding ring operation of the ductile cast iron pipe, and completely liberates workers from heavy manual welding.

[0055] In terms of welding quality, the device realizes revolutionary improvement. The core is that a closed-loop height tracking control system based on a contact type displacement sensor is introduced, which can realize real-time sensing and dynamic compensation of the ellipticity and local deformation of the pipe wall, so that the welding nozzle of the welding gun always maintains a constant optimal working distance. This not only ensures that the whole circle weld has uniform penetration and consistent shape, effectively eliminates quality defects such as incomplete penetration and undercut, and makes the welding quality no longer dependent on the personal skills and experience of the operator, realizes the stabilization and replicability of high-quality welding.

[0056] In addition, the device has excellent environmental friendliness and operation safety. The integrated welding dust collection device, combined with a flexible dust hood and a semi-closed fence, can efficiently capture the source before the dust spreads, significantly improving the working environment. At the same time, the device itself is provided with reliable mechanical limiting and travel protection, avoiding the risk of overtravel. This highly automated, high-quality and environmentally friendly and safe device greatly reduces the comprehensive operating cost and provides advanced equipment support for the upgrading of the ductile cast iron pipe industry.

[0057] It should be noted that the structures not introduced by the application do not involve the design points and improvement direction of the application, and are the same as or can be realized by the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 is a structural schematic diagram of the application;

[0059] Figure 2 is a second angle structural schematic diagram of the application;

[0060] Figure 3 is a structural schematic diagram of the lifting support frame of the application;

[0061] Figure 4 is another angle structural schematic diagram of the lifting support frame of the application;

[0062] Figure 5The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application;

[0063] Figure 6 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application Figure 5 The enlarged schematic view of the structure at A of the present application;

[0064] Figure 7 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application

[0065] Figure 8 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application Figure 7 The enlarged schematic view of the structure at B of the present application;

[0066] Figure 9 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application

[0067] Figure 10 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application

[0068] Figure 11 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application

[0069] Figure 12 The schematic view of the pipe rotating mechanism and the fixing frame structure of the present application

[0070] Reference signs:

[0071] 1, pipe conveying mechanism; 2, pipe rotating mechanism; 21, door type support seat; 211, back-shaped frame structure; 212, mounting hole; 213, fixed block; 214, concave positioning block; 22, support roller; 23, first chain wheel; 24, rotating shaft; 25, second chain wheel; 3, lifting support frame; 31, fixed base; 32, support stand; 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, support slide rail; 43, sliding positioning block; 44, rack; 45, gear; 46, third driving device; 47, right-angle positioning block; 5, fixing 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 fume 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 guide mechanism; 101, concave support; 102, copper grounding braid; 103, counterweight; 104, rotating limiting block; 105, vertical support frame. DETAILED DESCRIPTION

[0072] 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 implemented 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.

[0073] 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 shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply 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.

[0074] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features referred to. Therefore, the features defined with "first" and "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 explicitly specified and limited.

[0075] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing", "provided with", "provided in" and the like should be understood broadly, 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.

[0076] 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 can adopt the existing technology known to those skilled in the art.

[0077] The specific implementation of the present application will be described in detail below in combination with specific embodiments.

[0078] Referring to the drawings Figures 1-12 A ductile cast iron pipe welding ring welding device, comprising

[0079] The pipeline conveying mechanism 1 conveys and positions the ductile cast iron pipe;

[0080] Pipe rotating mechanism 2, arranged in the middle of the two pipe conveying mechanisms 1, used to carry and drive the ductile iron pipe to rotate around its own axis;

[0081] Lifting support frame 3, arranged adjacent to the pipe rotating mechanism 2;

[0082] Transverse moving mechanism 4, installed on the lifting support frame 3 and capable of vertical movement along it;

[0083] Welding torch fixing mechanism, connected to the end of the transverse moving mechanism 4 through a fixing frame 5, and the fixing frame 5 and the welding torch fixing mechanism can be driven to move forward and backward in the horizontal direction;

[0084] Wire feeder 6, installed on the fixing frame 5;

[0085] Welding power supply 7 and gas feeding device 8, arranged on the side of the lifting support frame 3, with their output ends connected to the wire feeder 6 and the welding torch fixing mechanism through high-temperature-resistant pipelines;

[0086] Among them, the welding torch installed on the welding torch fixing mechanism, the welding wire position of the welding torch nozzle can be adjusted and kept in close 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 supply 7 and the gas feeding device 8 work, thereby completing the automatic welding of the continuous annular weld on the outer wall of the ductile iron pipe.

[0087] In this embodiment, the pipe conveying mechanism 1 is used to receive, support and convey the ductile iron pipe from the previous process. This mechanism is usually composed of two parallel arranged roller beds, forming a conveying channel, the length and spacing of which can be adjusted according to the specifications of the pipe.

[0088] The pipe rotating mechanism 2 is embeddedly arranged in the middle of the pipe conveying mechanism 1. The ductile iron pipe can be conveyed by a travelling crane or a forklift, and when the ductile iron pipe is conveyed in place, the pipe rotating mechanism 2 is started to reliably clamp and drive the ductile iron pipe to rotate at a constant speed around its own central axis.

[0089] The lifting support frame 3 is fixedly installed on the foundation of the production line 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 feeding device 8, including argon / carbon dioxide mixed gas cylinders and pressure reducing valves, are arranged concentratedly behind the side of the lifting support frame 3, which is convenient for centralized management and maintenance.

[0090] The lateral moving mechanism 4 is installed on the front side of the lifting support frame 3 by means of sliding block or guide rail. The whole lateral moving mechanism 4 is lifted along the vertical direction. By controlling the switch of the side control cabinet, the welding height can be accurately set, so as to easily adapt to various pipe diameters of ductile iron pipe and ensure that the welding wire of the welding torch always aligns with the highest point of the pipeline, i.e. the predetermined position of the outer ring seam.

[0091] The fixing frame 5 is rigidly connected to the front end of the lateral moving mechanism 4. The lateral moving mechanism 4 itself also has a horizontal moving function, so that the fixing frame 5 can be driven to move along the pipeline axis direction, i.e. the front and back direction.

[0092] The wire feeder 6 is fixedly installed on one side of the fixing frame 5 and contains a wire feeding wheel and a pressing mechanism, which continuously and stably pushes the welding wire out from the welding wire reel. The welding torch fixing mechanism is installed on the other side of the fixing frame 5 opposite to the wire feeder 6, which firmly locks 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 with the outer wall of the ductile iron pipe.

[0093] The positive and negative output cables of the welding power source 7, the gas pipe of the gas feeding device 8 and the wire feeding hose of the wire feeder 6 are bundled together and wrapped with high-temperature-resistant corrugated pipe or winding pipe for protection, pass through the wire feeder 6 and are finally connected to the welding torch to provide energy, protective gas and filler material for the welding torch.

[0094] The working process of the device is as follows:

[0095] Firstly, a ductile iron pipe is moved to the working position by the pipeline conveying mechanism 1 or hoisting equipment, so that one end of the pipe is suspended above the pipeline rotating mechanism 2. Then, the operator controls the side control cabinet: firstly, the lateral moving mechanism 4 is controlled to lift, so that the welding torch basically reaches the height corresponding to the pipe diameter; secondly, the horizontal movement of the welding torch is controlled, so that the welding torch reaches the required axial position of the pipe end; finally, the welding wire of the welding torch is finally perfectly matched with the predetermined welding point of the pipe wall.

[0096] After positioning, the automatic welding program is started. The pipeline 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 source 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 torch successfully initiates the arc and the welding starts. Since the pipe continuously rotates, the welding wire of the welding torch can melt on the outer surface of the pipe to form a continuous, uniform and well-sealed annular weld.

[0097] After the welding is completed, the functional units are sequentially stopped, the pipeline rotating mechanism 2 is stopped, the welding head is lifted and returned to the original position. The welded pipe can be transported to the next process by the conveying mechanism, so as to complete a complete working cycle.

[0098] 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 improving the production efficiency and the uniformity of product quality, and reducing the labor intensity and skill requirements of the operator.

[0099] Please refer to Figure 5 with Figure 7 , the pipe rotating mechanism 2 includes 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 side end of the rotating shaft of the support roller 22 is respectively provided with a first sprocket 23, and the two first sprockets 23 located on the same door type support seat 21 are in different vertical planes; the bottom of the door type support seat 21 is also 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 by 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. In this 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 crossbeam of each door type support seat 21 through bearing seats. The two groups of support rollers 22 together 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.

[0100] 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 meshingly connected by a closed transmission chain.

[0101] 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 rigidly connected to the rotating shafts 24 on the left and right door type support seats 21 through couplings.

[0102] 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 rotating speed in the welding process, which is a key prerequisite for obtaining high-quality girth welds.

[0103] 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.

[0104] 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 vertically extends 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, thereby ensuring the stability of the whole device during operation. The support column 32 is vertically fixed to the fixed base 31, thereby 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. The output shaft of the second driving motor 34 vertically extends downward and is connected to a precise 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 rotated, the rotating screw rod is driven to rotate, thereby converting into the linear motion of the lifting vertical plate 35 in the vertical direction.

[0105] 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.

[0106] Please refer to Figure 3 and Figure 4The lateral moving mechanism 4 comprises a lateral support plate 41, support slide rails 42, slide 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 slide 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 slide positioning blocks 43 are installed on the right-angle positioning blocks 47, and the slide positioning blocks 43 and the support slide 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 component adopts 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 extends forward through the lifting vertical plate 35, and the gear 45 is installed at the end portion; 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 slide positioning blocks 43 are installed on each right-angle positioning block 47; the support slide rails 42 matched with the slide positioning blocks 43 are fixedly installed on both sides of the lateral support plate 41; the slide positioning blocks 43 and the support slide rails 42 jointly form a high-rigidity linear guide pair.

[0107] 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.

[0108] The T-shaped fixing column 51 is fixedly connected with one side of the fixing frame 5.

[0109] The fine adjustment lifting platform 53 is slidably connected with the lifting base 52 through a linear guide rail assembly.

[0110] The fourth driving mechanism 54 is fixedly installed on the top of the lifting base 52; the precision lead screw 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.

[0111] The welding torch and the contact displacement sensor 55 are fixedly installed side by side on the fine adjustment 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;

[0112] 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 to the fourth driving mechanism 54, thereby forming a closed-loop height tracking control system. The contact displacement sensor 55 and the ductile iron pipe wall are in contact and expansion, so as to control the lifting of the fine adjustment lifting platform 53, so that the distance between the welding wire of the welding torch and the ductile iron pipe is kept consistent at all times, thereby improving the welding quality.

[0113] The height tracking control system in the application can be realized by using the prior art, and the specific process is as follows:

[0114] 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, which can be realized by using the prior art. In the embodiment, the contact displacement sensor 55 adopts the LVDT principle or the resistance principle. When the pipe wall jumps radially due to the non-circularity or deformation, the probe is pushed to expand and contract. The inside of the sensor converts the linear displacement into proportional electrical signal analog voltage / current or digital signal real-time output.

[0115] 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 circular pipe wall, and calculates the deviation between the two.

[0116] 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 micro-lifting movement through a precision screw-nut pair. The specific process is as follows: when the pipe wall appears to be 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 appears to be 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 in 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 the shape error of the pipe material are fundamentally avoided, the welding height is self-adaptively adjusted, manual intervention is not needed, the dependence on the experience of the operator is reduced, and the production automation level and efficiency are improved.

[0117] Please pay attention to Figure 10 It also includes a welding fume collecting device 9; the welding fume collecting device 9 includes a positioning plate 91, a horn-shaped dust cover 92, a corrugated pipe 93, and a dust collector 94;

[0118] The positioning plate 91 is installed on the other side of the fixed frame 5 relative to the wire feeder 6;

[0119] The positioning plate 91 is provided with a collecting hole 95, and the horn-shaped dust cover 92 is installed at the collecting hole 95, with its large-diameter end facing the welding operation point;

[0120] The small-diameter end of the horn-shaped dust cover 92 is connected to the air inlet of the dust collector 94 through the corrugated pipe 93. In this embodiment, the horn-shaped dust cover 92 is installed on the collecting hole 95, and the bottom of the large-diameter cover opening is the working position of the welding torch and the pipe wall, so as to maximize the smoke capture range. The outlet of the horn-shaped dust cover 92 is connected to one end of a corrugated pipe 93. The corrugated pipe 93 has the characteristics of being bendable and not easy to be crushed, and a metal spiral support skeleton can be embedded inside to maintain the ventilation cross section, and the outside is a flexible material resistant to high temperature. The other end of the corrugated pipe 93 is connected to the dust collector 94. The dust collector 94 is a standard industrial equipment in the prior art, such as a bag-type dust collector or an electrostatic precipitator, which can generate a negative pressure suction and filter and purify the inhaled smoke dust. The dust collector 94 is started before or at the same time as the welding program. The negative pressure suction generated by the dust collector 94 is conducted to the horn-shaped dust cover 92 through the corrugated pipe 93, forming a stable directional airflow field at the cover opening.

[0121] When welding starts, a large amount of welding fume generated in the rising and diffusion process will be effectively captured by the directional airflow, and then sucked into the dust collector 94 through the horn-shaped dust cover 92 and the corrugated pipe 93 for purification treatment.

[0122] The corrugated pipe 93 has good bendability, and can be flexibly adjusted in direction and length according to the site layout to avoid interference with other parts of the equipment. In addition, the middle section of the corrugated pipe 93 can be suspended from the top of the workshop by an additional suspension device such as a sling, so as to reduce the load of the fixed frame 5 caused by the weight of the corrugated pipe 93, and more accurately fix the orientation of the horn-shaped dust cover 92, ensuring that it is always efficiently aligned with the welding point.

[0123] Please pay attention to Figure 1 With Figure 10The fixed frame 5 is provided with a high-temperature-resistant flexible fence 96 around it; the high-temperature-resistant flexible fence 96 forms a semi-closed collection space around the working area of the welding gun, and the opening of the horn-shaped dust cover 92 is located at the upper part of the collection space. In this embodiment, during welding operation, the welding fume mainly rises and diffuses upward. The collection space formed by the high-temperature-resistant flexible fence 96 can effectively block the fume from escaping in a large area and limit most of the fume in a relatively small range.

[0124] Due to the constraint of the fence, the rising fume is more easily concentrated and gathered at the opening of the horn-shaped dust cover 92 located at the upper part of the space, so as to be efficiently sucked by the negative pressure airflow.

[0125] This structure significantly reduces the unorganized emission of fume, greatly improves the capture rate and collection efficiency of fume under the same suction of the dust collector, and further improves the working environment.

[0126] Further comprising a limiting flow guide mechanism 10, which is connected with the welding power supply 7;

[0127] 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;

[0128] The concave bracket 101 is horizontally arranged 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 thereof naturally droops and is used for supporting the pipe body of the ductile iron pipe;

[0129] One end of the copper grounding braid 102 is connected with the concave bracket 101, and the other end extends downward, passes around a rotating roller, and is connected with the counterweight 103. This 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;

[0130] 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;

[0131] Please pay attention to Figure 11 and 12A vertical support frame 105 is fixed to the side of the concave support 101, and a rotating limiting block 104 is mounted 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 to abut against the end surface of the bottom of the ductile iron pipe to realize axial limiting during the welding process. In the embodiment, the middle section of the copper grounding braid 102 naturally droops under the action of gravity to form an arc-shaped bearing surface. When the ductile iron pipe is placed on the pipe rotating mechanism 2, the pipe body bottom is placed on the arc-shaped copper grounding braid 102. One end of the copper grounding braid 102 is fixed, and the other end is connected to a counterweight 103 after winding around a rotating roller downward. The counterweight 103 provides a continuous upward tension for the copper grounding braid 102 through a pulley mechanism, so that the copper grounding braid 102 can be closely adhered to the pipe wall bottom surface to form stable electrical contact regardless of the change of the pipe diameter.

[0132] During the welding, the positive electrode of the welding power source 7 is connected to 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 to 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, the welding wire, the pipe body, the copper grounding braid 102, and back to the power source. The flexible contact mode avoids the damage to the surface of the pipe body caused by rigid sparking, and ensures the stability of the current loop.

[0133] A vertical support frame 105 is fixed to the side of the concave support 101, and a rotating limiting block 104 is mounted 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 to abut against the end surface of the bottom of the ductile iron pipe to realize axial limiting during the welding process. In the embodiment, the middle section of the copper grounding braid 102 naturally droops under the action of gravity to form an arc-shaped bearing surface. When the ductile iron pipe is placed on the pipe rotating mechanism 2, the pipe body bottom is placed on the arc-shaped copper grounding braid 102. One end of the copper grounding braid 102 is fixed, and the other end is connected to a counterweight 103 after winding around a rotating roller downward. The counterweight 103 provides a continuous upward tension for the copper grounding braid 102 through a pulley mechanism, so that the copper grounding braid 102 can be closely adhered to the pipe wall bottom surface to form stable electrical contact regardless of the change of the pipe diameter.

[0134] The above-described embodiments only express certain embodiments of the present application, and the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application; it should be noted that for ordinary skilled persons in the art, a number of 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 patent of the present application should be subject to the appended claims.

Claims

1. A ductile cast iron pipe welding ring welding apparatus characterized by: Comprising a pipeline conveying mechanism (1) for conveying and positioning the ductile 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 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) installed on the lifting support frame (3) and capable of vertically moving along the same; a welding gun fixing mechanism connected to the end of the transverse moving mechanism (4) through a fixing frame (5), the transverse moving mechanism (4) being capable of driving the fixing frame (5) and the welding gun fixing mechanism to move forward and backward in the horizontal direction; a wire feeder (6) installed on the fixing frame (5); a welding power supply (7) and a gas feeding device (8) arranged at the side of the lifting support frame (3), the output ends of which are connected to the wire feeder (6) and the welding gun fixing mechanism through high-temperature resistant pipelines; wherein the welding gun installed on the welding gun fixing mechanism, the welding wire extending from the welding nozzle of the welding gun can be adjusted and kept in close contact with the outer wall of the ductile iron pipe placed on the pipeline rotating mechanism (2); during welding, the pipeline 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 supply (7) and the gas feeding device (8) work, so as to complete the automatic welding of continuous annular welds on the outer wall of the ductile iron pipe; further comprising a limiting flow guide mechanism (10) 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 block (103) and a rotating limiting block (104); the concave bracket (101) is arranged across below the pipeline rotating mechanism (2), and the top of the same is provided with the copper grounding braid (102); the copper grounding braid (102) is a soft braided conductor, the middle part of which 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 thereof extends downward, passes around a rotating roller and is connected with the counterweight block (103), the copper grounding braid (102) always keeps in a tension state under the action of the counterweight block (103) and is in close contact with the bottom surface of the pipe body; the end of the copper grounding braid (102) is connected with the negative cable of the welding power supply (7) through a conductive clamp; a vertical support frame (105) is fixed to the side of the concave bracket (101), and the top of the same is provided with the rotating limiting block (104) 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.

2. A ductile cast iron pipe welding ring welding apparatus according to claim 1, characterized in that: The pipeline rotating mechanism (2) comprises two symmetrical door type support seats (21), two groups of support rollers (22) are rotatably installed on the top of each door type support seat (21), first chain wheels (23) are respectively installed on the outer side ends of the rotating shafts of the support rollers (22), the two first chain wheels (23) on the same door type support seat (21) are located in different vertical planes, rotating shafts (24) driven by a first driving motor are further arranged at the bottoms of the door type support seats (21), four second chain wheels (25) are correspondingly installed on the rotating shafts (24), the first chain wheels (23) and the second chain wheels (25) 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 (24) on the two door type support seats (21) through couplings.

3. A ductile cast iron pipe girth welding apparatus according to claim 2, characterized in that: The top of the door type support seat (21) is a meandering frame structure (211), a plurality of spaced mounting holes (212) are symmetrically formed on the meandering frame structure (211) along the length direction thereof, the support rollers (22) are installed on the meandering frame through an assembled bearing seat, the assembled bearing seat comprises a fixed block (213) and a concave positioning block (214), the fixed block (213) is selectively fixed on the mounting holes (212) at different positions through bolts, 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 support roller (22) is supported in the bearing.

4. The device for welding a ferrule to a duct of ductile cast iron according to claim 1, characterized in that: The lifting support frame (3) comprises a fixed base (31), a support column (32), a fixed table (33), a second driving motor (34), a rotating lead screw and a lifting vertical plate (35), the fixed base (31) is fixed to the ground through foundation 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), the output shaft of the second driving motor (34) 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 (35) form a threaded transmission pair.

5. A ductile cast iron pipe girth welding apparatus according to claim 4, characterized in that: 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 plate (322) is matched with the lifting positioning track (321) through a sliding block, 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 plate (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 track (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.

6. A ductile cast iron pipe girth welding apparatus according to claim 5, characterized in that: The transverse moving mechanism (4) comprises a transverse support plate (41), support sliding rails (42), sliding positioning blocks (43), a rack (44), a gear (45) and a third driving device (46); the transverse support plate (41) is connected with the lifting vertical plate (35) through the support sliding rails (42) fixed on the two sides thereof, right-angle positioning blocks (47) are symmetrically arranged on the front surface of the lifting vertical plate (35), the sliding positioning blocks (43) are arranged 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 arranged on the bottom of the transverse support plate (41); a placing gap is formed in the rear side of the lifting vertical plate (35), the third driving device (46) is fixedly arranged in the placing gap, the output shaft of the third driving device (46) extends forward and is connected with the gear (45), and the gear (45) is meshed with the rack (44).

7. The device for welding of the ferrule to the pipe according to claim 1, characterized in that: The welding gun fixing mechanism comprises a T-shaped fixing column (51), a lifting base (52), a fine adjustment lifting table (53), a fourth driving mechanism (54) and a contact type displacement sensor (55); One side of the T-shaped fixing column (51) is fixedly connected with the fixing frame (5); The fine adjustment lifting table (53) is slidably connected with the lifting base (52) through a linear guide rail assembly; The fourth driving mechanism (54) is fixedly arranged on the top of the lifting base (52), a precision lead screw connected with the output end of the fourth driving mechanism (54) and a nut arranged on the fine adjustment lifting table (53) form a transmission pair, and the fourth driving mechanism (54) is used for driving the fine adjustment lifting table (53) to perform precise displacement in the vertical direction; The welding gun and the contact type displacement sensor (55) are fixedly arranged side by side on the fine adjustment lifting table (53), and the detection direction of the contact type displacement sensor (55) and the nozzle of the welding gun are both perpendicular to the axis direction of the ductile iron pipe.

8. The device for welding of the ferrule to the pipe according to claim 1, characterized in that: Further comprising 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 arranged on the other side of the fixing frame (5) relative to the wire feeder (6); The positioning plate (91) is provided with a collecting hole (95), and the horn-shaped dust cover (92) is installed at the collecting hole (95) and has a large-diameter end facing the welding operation point; The small-diameter end of the horn-shaped dust cover (92) is connected with the air inlet of the dust collector (94) through the bellows (93).

9. A ductile cast iron pipe girth welding apparatus according to claim 8, characterized in that: The fixed frame (5) is provided with a high-temperature-resistant flexible fence (96) around the fixed frame (5); the high-temperature-resistant flexible fence (96) forms a semi-closed collecting space around the operation area of the welding torch, and the cover opening of the horn-shaped dust cover (92) is located at the upper part of the collecting space.

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