Hot melt adhesive intelligent heat treatment pipe nitrogen charging and pressure maintaining full-automatic capping equipment and method based on PLC closed loop control

Abstract

The present application relates to the technical field of heat treatment pipe production and processing, in particular to a hot melt glue intelligent heat treatment pipe nitrogen filling and pressure maintaining full-automatic sealing cover equipment and method based on PLC closed loop control, comprising a hot melt glue machine, a placing assembly is arranged in the hot melt glue machine, push cover assemblies are arranged on both sides of the placing assembly, the placing assembly is composed of a plurality of bases, two supporting rods and a rotating roller, a track is arranged in the supporting rod, and a driving structure is arranged in the hot melt glue machine; the push cover assembly is composed of a storage frame, a sealing cover and a pushing structure. The placing assembly is arranged to support the heat treatment pipe to be processed and drive it to rotate around its own axis, so that automatic and uniform glue spraying is realized; the push cover assembly is arranged to press and assemble the sealing cover to both ends of the heat treatment pipe and complete the nitrogen filling and pressure maintaining operation, so that automatic installation of the sealing cover is realized, labor cost is reduced, and glue spraying sealing quality is improved.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment tube production and processing technology, specifically a fully automatic capping device and method for hot melt adhesive intelligent heat treatment tubes with nitrogen filling and pressure holding based on PLC closed-loop control. Background Technology

[0002] Heat-treated tubes refer to tubes that have undergone processes such as quenching, tempering, and annealing to change the internal structure of the metal and obtain specific mechanical properties. Some heat-treated tubes are used in precision machinery, such as bearing steel tubes, high-pressure oil tubes, and precision machinery tubes. After production, in order to avoid oxidation and rust on the inner wall during storage and transportation, heat-treated tubes need to be filled with nitrogen, pressurized, and sealed before leaving the factory.

[0003] For example, patent application CN218703492U discloses a hot-melt outer plate plug, which includes a sealing plug and a top cover outer plate. The top cover outer plate has a through hole, and the sealing plug is disposed on the top cover outer plate through the through hole. The sealing plug includes a plug body and a plug top. The plug top is disposed at the upper end of the plug body. The side wall of the plug body is provided with a retaining corner. The edge of the plug top is provided with an arc-shaped structure. The curvature angle of the arc-shaped structure is set towards the plug body. A gap is formed between the arc-shaped structure and the retaining corner, and the gap is filled with hot-melt adhesive.

[0004] Based on the above cases, in the existing technology, similar hot melt adhesive sealing operations are mostly carried out by workers manually installing the sealing caps and sealing them with a handheld hot melt glue gun. This operation is cumbersome and has high labor costs. The uniformity of manual glue spraying is also poor. Summary of the Invention

[0005] The purpose of this invention is to provide a fully automatic capping device and method for hot melt adhesive intelligent heat treatment tubes with nitrogen filling and pressure holding based on PLC closed-loop control. This invention sets up a placement component and a cap pushing component to support the heat treatment tube to be processed and drive it to rotate around its own axis, and press the sealing caps onto both ends of the tube to complete the nitrogen filling and pressure holding operation, thereby realizing automatic installation of the sealing caps, reducing labor costs, and improving the quality of adhesive spraying and sealing.

[0006] To achieve the above objectives, the present invention provides a fully automatic capping device for intelligent heat treatment tubes with nitrogen filling and pressure holding based on PLC closed-loop control, including a hot melt adhesive machine controlled by a PLC system. The hot melt adhesive machine is equipped with a placement component for placing the heat treatment tube. The placement component is symmetrically provided with cap-pushing components on the left and right sides for sealing both ends of the heat treatment tube. The placement assembly consists of several bases, two support rods hinged to the left and right side walls of the bases, and a rotating roller rotatably connected to the inner side wall of the top of the support rod. The support rod is equipped with a track for driving the rotating roller to rotate. The hot melt glue machine is equipped with a drive structure. The heat treatment tube is placed between the front and rear support rods. After the push cover assembly seals both ends of the heat treatment tube, the drive structure is activated to drive several tracks to rotate, thereby driving several rotating rollers to rotate synchronously. The heat treatment tube is driven to rotate by the friction between the rotating roller and the heat treatment tube. The push-cover assembly consists of a storage frame, a sealing cover placed inside the storage frame, and a push structure for sliding the sealing cover. A support plate is provided between two support rods on the same base to ensure that the heat treatment tube and the sealing cover are placed coaxially. The sealing cover at the bottom of the storage frame is placed on the outer end of the corresponding side support plate. After the heat treatment tube is placed in the placement assembly, the push structures on both sides are activated to move the sealing covers at the bottom of both sides towards each other and insert them into both ends of the heat treatment tube for sealing.

[0007] In this design, considering that some heat treatment tubes used in precision machinery, such as bearing steel tubes, high-pressure oil tubes, and precision machinery tubes, require nitrogen purging and pressure sealing before leaving the factory to prevent oxidation and rusting of the inner wall during storage and transportation, this is necessary. However, in existing technologies, workers typically install the sealing caps manually using a handheld hot melt glue gun, which is cumbersome, labor-intensive, and results in poor uniformity of the glue spraying. Therefore, this invention uses a placement component to support the heat treatment tube to be processed and drive it to rotate around its own axis, achieving automatic and uniform glue spraying. By setting up a cap-pushing component, sealing caps are pressed onto both ends of the heat treatment tube, and nitrogen purging and pressure sealing are completed, achieving automatic cap installation, reducing labor costs, and improving the quality of glue spraying and sealing.

[0008] In the technical solution of the present invention, the left and right side walls of the base are provided with arc-shaped sliding grooves, and the two sliding grooves on the same base are centrally symmetrically arranged. The center of the sliding groove is coaxially arranged with the bottom end of the support rod. An arc-shaped limiting rod is concentrically fixed in the sliding groove, and an arc-shaped first spring is sleeved on the limiting rod.

[0009] In the technical solution of the present invention, two support rods on the same base are arranged alternately, and a pressure plate is fixed on the inner side of the support rod near the middle. The pressure plate extends into the corresponding sliding groove, and the limiting rod passes through the corresponding pressure plate and the two are slidably connected. The first spring is disposed between the pressure plate and the bottom surface of the sliding groove.

[0010] In this setup, by setting a limiting rod and a first spring, the heat-treated tube is placed between two front and rear rotating rollers. When the weight of the tube body and the elastic force of the first spring on both sides reach a balance, the heat-treated tube achieves self-alignment and support, adapting to different specifications of tubes within a certain diameter range.

[0011] In the technical solution of the present invention, the support plate is composed of an inner arc plate and an outer arc plate fixedly connected. The inner arc plate abuts against the outer wall of the heat treatment pipe, and the outer arc plate abuts against the outer wall of the sealing cover. The front and rear sides of the inner arc plate are connected to the corresponding support rod near the top by elastic bands. The vertical height difference between the outer arc plate and the inner arc plate is equal to the thickness of the sealing cover.

[0012] In this setup, an inner arc plate and an outer arc plate are used. The front and rear sides of the inner arc plate are connected to the top of the corresponding support rod via elastic bands, allowing the support plate to float synchronously with the opening and closing of the support rod, always maintaining a coaxial relative position with the heat treatment tube.

[0013] In the technical solution of the present invention, the driving structure includes a servo motor fixed at the bottom of the hot melt glue machine, an active gear fixed coaxially with the output shaft of the servo motor, and a shaft rotatably connected coaxially with the bottom end of several support rods. The right end of the shaft is coaxially fixed with a driven gear that meshes with the active gear. The shaft passes through several bases and the two are rotatably connected.

[0014] In the technical solution of the present invention, the shaft is coaxially and fixedly connected to the track wheel at the bottom end of the track, and the track wheel at the top end of the track is coaxially and fixedly connected to the central shaft of the corresponding rotating roller.

[0015] In this setup, by setting up a drive structure, the power output by the servo motor is transmitted to the shaft through the driving gear and driven gear, and then synchronously drives all the rotating rollers to rotate in the same direction through the tracks in each support rod. The friction between the rotating rollers and the outer wall of the heat treatment tube drives the tube to rotate at a uniform speed, ensuring that the circumferential adhesive thickness is uniform.

[0016] In the technical solution of the present invention, the inner side of the storage frame is a protective net to prevent the sealing cover from detaching from the storage frame. A protrusion is coaxially fixed in the middle of the outer wall of the sealing cover. A limiting groove adapted to the size of the protrusion is provided in the middle of the outer wall of the storage frame. The width of the left and right inner walls of the storage frame is equal to the left and right length of the sealing cover. An air valve for inflation is fixed in the middle of the protrusion.

[0017] In this design, by incorporating a protrusion and a limiting groove, the protrusion embeds into the limiting groove when the sealing caps are stacked, achieving vertical sliding guidance and ensuring that the sealing caps fall neatly in the vertical direction without circumferential deflection. The distance between the left and right inner walls of the storage frame is equal to the left and right lengths of the sealing caps, further restricting the lateral displacement of the sealing caps.

[0018] In the technical solution of the present invention, the pushing structure includes a first hydraulic cylinder, an intermediate plate coaxially fixed with the output shaft of the first hydraulic cylinder, and a plurality of extrusion members regularly distributed in a ring on the inner sidewall of the intermediate plate. An insertion tube is coaxially fixed on the inner sidewall of the intermediate plate, and an air inlet pipe for supplying nitrogen to the insertion tube is provided on the sidewall of the intermediate plate. A second hydraulic cylinder is fixed below the first hydraulic cylinder for adjusting the vertical height of the first hydraulic cylinder so that it is coaxial with the protrusion.

[0019] In this setup, by setting up a second hydraulic cylinder and adjusting the vertical height of the first hydraulic cylinder, the axis of the pushing structure is kept coaxial with the axis of the current lowest sealing cover, adapting to the sealing operation of heat-treated pipes of different diameters.

[0020] In the technical solution of the present invention, the extrusion member is composed of a movable rod and a fixed rod. The outer end of the movable rod is inserted into the corresponding fixed rod and the two are slidably connected. A second spring is provided in the fixed rod. The second spring is disposed between the outer end of the movable rod and the inner groove wall of the fixed rod. The outer end of the fixed rod is fixed to the inner side wall of the intermediate plate.

[0021] In this setup, by incorporating a movable rod, a fixed rod, and a second spring, hard contact is used to prevent damage to the sealing cap and the pipe end. At the same time, it ensures that the insertion tube can still reliably connect with the valve after being press-fitted in place, thus achieving stable nitrogen charging.

[0022] On the other hand, the present invention also provides a fully automatic capping method for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control with nitrogen filling and pressure holding, using the above-mentioned fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control, including the following steps: S1. Add an appropriate number of sealing caps to the storage box, place the heat treatment tube between the front and rear sets of rotating rollers, and the weight of the heat treatment tube presses down to make the support rod and rotating roller expand outward and press down to the bottom of the middle of the inner arc plate until the weight of the heat treatment tube is balanced with the elastic force of all the first springs. The bottom sealing cap abuts against the outer arc plate and automatically falls on the bottom of the middle of the outer arc plate under its own weight. Since the difference between the outer diameter of the sealing cap and the outer diameter of the heat treatment tube is equal to the thickness of the sealing cap, the sealing cap and the heat treatment tube are in a coaxial state at this time. S2. After the heat treatment tube is placed and balanced, start the second hydraulic cylinder to adjust the position of the first hydraulic cylinder to be coaxial with the bottom sealing cover. Then close the second hydraulic cylinder and start the first hydraulic cylinder to drive the middle plate and the extrusion piece to push the sealing covers on both sides to move towards each other and insert them into the two ends of the heat treatment tube. S3. When the inner surface of the sealing cap is inserted into the heat-treated tube end, the first hydraulic cylinder continues to drive the intermediate plate to move inward, causing the movable rod and the fixed rod to slide relative to each other and squeeze the second spring until the tube is fully inserted into the valve. Then the first hydraulic cylinder is closed and nitrogen is charged into the valve through the intake pipe to maintain pressure. S4. After inflation is complete, stop inflation and start the position adjustment device of the hot melt glue machine 100 to adjust the hot melt glue nozzle to correspond to the circumferential joint position of the outer end of the sealing cover 301. Then, start the servo motor to drive all the rotating rollers to rotate synchronously through the sequential transmission of the drive gear, driven gear, shaft and track. Then, the friction between the rotating rollers and the heat treatment tube drives the heat treatment tube to rotate. At the same time, start the glue spraying device of the hot melt glue machine to spray glue between the outer end of the sealing cover and the outer wall of the heat treatment tube for sealing. After the glue spraying is completed, dry it to complete the nitrogen filling and pressure sealing.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, closed-loop control is achieved through a PLC system, which coordinates the operation of the placement component and the push-cap component. It can automatically complete the entire process of sealing cap feeding, tube body support and centering, simultaneous capping at both ends, nitrogen filling and pressure holding, circumferential glue spraying and sealing, and drying. It replaces the traditional manual assembly of sealing caps and hand-held hot melt glue gun sealing operation mode, reduces the intensity of manual operation and labor costs, eliminates human operation errors, and significantly improves the production efficiency and batch qualification rate of nitrogen filling and capping of heat treatment tubes.

[0024] 2. In this invention, a floating support structure consisting of a hinged support rod, an arc-shaped sliding groove, a limiting rod, and a first spring is adopted. The heat-treated tube can achieve self-adaptive centering and positioning by its own weight, which can adapt to different specifications of tubes within a certain diameter range, making the equipment highly versatile. With the support plate floating synchronously with the support rod, the height difference design of the inner and outer arc plates ensures that the stacked and falling sealing caps and tubes automatically maintain a coaxial state, eliminating the need for repeated manual calibration and alignment. This not only improves the efficiency of loading and clamping but also ensures the coaxiality of the pressing process from a structural perspective, avoiding sealing failure caused by pressing misalignment.

[0025] 3. In this invention, the sealing cap pressing and nitrogen filling functions are integrated into the same pushing structure. After the sealing cap is pressed into place, the tube can automatically connect with the valve to complete the nitrogen filling without the need for step-by-step switching of workstations, resulting in a high degree of process integration. With the annularly distributed elastic extrusion structure, the second spring provides a buffer stroke to avoid hard contact damage to the sealing cap and tube end, while ensuring a tight connection between the nitrogen filling tube and the valve. Combined with the real-time closed-loop control of nitrogen pressure by the PLC system, the pressure holding value in the tube can be accurately controlled, significantly improving the consistency of nitrogen filling and pressure holding and the reliability of sealing. Attached Figure Description

[0026] Figure 1 This is a simplified schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal workings of the hot melt adhesive machine of the present invention; Figure 3 This is a schematic diagram of the placement component and the push-cover component in this invention; Figure 4This is a schematic diagram of the component placement in this invention; Figure 5 This is an exploded view of the base and support rod in this invention; Figure 6 This is an exploded view of the support rod in this invention; Figure 7 This is a schematic diagram of the storage frame and sealing cap in this invention; Figure 8 This is a schematic diagram of the push-cover assembly in this invention; Figure 9 This is a schematic diagram of the pushing structure in this invention; Figure 10 This is a schematic diagram of the extrusion rod in this invention; Explanation of reference numerals in the attached figures: 100. Hot melt glue machine; 200. Placement component; 201. Base; 2011. Sliding groove; 2012. Limiting rod; 2013. First spring; 202. Support rod; 2021. Pressure plate; 203. Rotary roller; 204. Support plate; 205. Track; 210. Drive structure; 211. Servo motor; 212. Drive gear; 213. Driven gear; 214. Shaft; 300. Push-cover assembly; 301. Sealing cover; 3011. Protrusion; 3012. Valve; 302. Material storage frame; 3021. Limiting groove; 310. Pushing structure; 311. First hydraulic cylinder; 312. Intermediate plate; 3121. Insert tube; 3122. Air inlet pipe; 313. Extrusion part; 3131. Movable rod; 3132. Fixed rod; 3133. Second spring; 314. Second hydraulic cylinder; 400. Heat treatment tube. Detailed Implementation

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0028] Unless otherwise expressly stated, throughout this specification, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0029] Reference Figures 1-10 As shown, this embodiment provides a technical solution: This fully automatic capping device for heat treatment tubes using PLC closed-loop control includes a hot melt adhesive machine 100 with closed-loop control via a PLC system. The hot melt adhesive machine 100 has a placement component 200 inside its cavity, which supports the heat treatment tube 400 to be processed and drives it to rotate around its own axis. Push-cap components 300 are symmetrically arranged on the left and right sides of the placement component 200 to seal both ends of the heat treatment tube 400 and complete the nitrogen filling and pressure holding operation. The hot melt adhesive machine 100 has a built-in hot melt adhesive spraying and drying mechanism with multi-dimensional adjustable position, used to apply and cure hot melt adhesive at the joint between the sealing cap 301 and the heat treatment tube 400, achieving a sealed protection at the tube end. In this embodiment, the PLC system integrates a pressure detection module, a position detection module, and a temperature detection module. It can adjust the operation actions in real time according to parameters such as the nitrogen pressure inside the tube, the pressure displacement of the sealing cap, and the temperature of the hot melt adhesive, forming a closed-loop control throughout the entire process. This ensures the consistency of the capping and pressure holding quality of different batches. The specific principle is existing technology and will not be elaborated here.

[0030] Please see Figures 1-6 As shown, the placement assembly 200 is provided with several sets of support units spaced apart along the axial direction of the heat treatment tube 400. Each set of support units includes a base 201, two support rods 202, and a rotating roller 203. The bottom of the base 201 is fixed to the bottom surface of the inner cavity of the hot melt glue machine 100 by bolts. The support centers of the multiple sets of support units are kept coaxial and jointly support the outer wall of the heat treatment tube 400.

[0031] Furthermore, arc-shaped sliding grooves 2011 are provided on both the left and right side walls of the base 201. The two sliding grooves 2011 on the same base 201 are centrally symmetrically arranged, and the center of the sliding groove 2011 is coaxial with the hinge axis at the bottom of the support rod 202. An arc-shaped limiting rod 2012 is concentrically fixed in the sliding groove 2011, and an arc-shaped first spring 2013 is sleeved on the limiting rod 2012.

[0032] In addition, the two support rods 202 on the same base 201 are staggered in the front-to-back direction to avoid structural interference during opening, closing and rotation. A pressure plate 2021 is fixed to the inner side of the support rod 202 near the middle. The pressure plate 2021 extends into the sliding groove 2011 on the corresponding side. The limiting rod 2012 passes through the pressure plate 2021 and the two are slidably engaged. The first spring 2013 is disposed between the pressure plate 2021 and the bottom surface of the sliding groove 2011. Under normal conditions, it is in a compressed state and provides an inward restoring force for the support rod 202.

[0033] When the heat-treated tube 400 is placed between the front and rear rollers 203, the tube's own weight presses the rollers 203 downwards, causing the two support rods 202 to expand outwards on both sides around the bottom hinge. The pressure plate 2021 slides along the limiting rod 2012 and further compresses the first spring 2013 until the weight of the tube and the elastic force of the first springs 2013 on both sides reach a balance, realizing the self-adaptive centering and support of the heat-treated tube 400, which can adapt to different specifications of tubes within a certain diameter range.

[0034] Furthermore, a support plate 204 is provided between the two support rods 202 on the same base 201. The support plate 204 is integrally fixedly connected by an inner arc-shaped plate and an outer arc-shaped plate. The arc surface of the inner arc-shaped plate is adapted to the outer wall of the heat treatment tube 400 with the largest diameter, and the arc surface of the outer arc-shaped plate is adapted to the outer wall of the sealing cap 301 with the largest diameter. The front and rear sides of the inner arc-shaped plate are connected to the top position of the corresponding support rod 202 by elastic bands, so that the support plate 204 can float synchronously with the opening and closing of the support rod 202, and always maintain a coaxial relative position with the heat treatment tube 400.

[0035] Specifically, the height difference between the outer arc plate and the inner arc plate is equal to the thickness of the sealing cover 301. When the heat treatment tube 400 is positioned at the lowest point of the inner arc plate, the sealing cover 301, which is stacked and falls to the lowest point of the outer arc plate, can automatically maintain a coaxial state with the heat treatment tube 400. This ensures the coaxiality of the subsequent pressing without manual alignment and avoids sealing failure caused by misalignment during pressing.

[0036] In addition, the hot melt glue machine 100 is equipped with a drive structure 210, which drives all the rotating rollers 203 to rotate synchronously, thereby driving the heat treatment tube 400 to rotate at a uniform speed. The drive structure 210 includes a servo motor 211, a drive gear 212, a driven gear 213, a shaft 214, and a track 205 built into the support rod 202. The servo motor 211 is fixed to the bottom of the inner cavity of the hot melt glue machine 100 by a motor mount, and the drive gear 212 is coaxially fixed on its output shaft. The shaft 214 is arranged horizontally along the axial direction of the heat treatment tube 400, passes through all the bases 201 and is rotatably connected to the bases 201; the driven gear 213 is coaxially fixed to the right end of the shaft 214, and the driven gear 213 meshes with the drive gear 212.

[0037] Specifically, each support rod 202 has a track drive cavity inside, and the track 205 is installed in the drive cavity; the shaft 214 is coaxially and fixedly connected to the track wheel at the bottom end of the track 205, and the track wheel at the top end of the track 205 is coaxially and fixedly connected to the central shaft of the corresponding roller 203. The power output by the servo motor 211 is transmitted to the shaft 214 through the driving gear 212 and the driven gear 213, and then synchronously drives all the rollers 203 to rotate in the same direction through the track 205 in each support rod. The friction between the rollers 203 and the outer wall of the heat treatment tube 400 drives the tube to rotate at a uniform speed, ensuring that the circumferential adhesive thickness is uniform.

[0038] Please see Figures 7-10 As shown, two sets of push-cap assemblies 300 are symmetrically arranged on both sides of the placement assembly 200. Each push-cap assembly 300 includes a storage frame 302 for stacking and storing sealing caps 301, and a pushing structure 310 for pressing and filling the sealing caps 301 with nitrogen. The storage frame 302 is a vertically arranged elongated frame with a protective mesh structure on its inner wall, which reduces the overall weight and prevents the sealing caps 301 from coming off from the side. The outer wall of the sealing cap 301 has an annular protrusion 3011 integrally formed on the middle of its outer wall, and a limiting groove 3021 with a size adapted to the protrusion 3011 is provided in the middle of the outer wall of the storage frame 302. When the sealing caps 301 are stacked, the protrusion 3011 is embedded in the limiting groove 3021 to achieve vertical sliding guidance, ensuring that the sealing caps 301 fall neatly in the vertical direction without circumferential deflection. The distance between the left and right inner walls of the storage frame 302 is equal to the left and right lengths of the sealing cover 301, which further restricts the lateral displacement of the sealing cover 301. It should be noted that the left and right lengths of the sealing cover 301 are the same for different diameters.

[0039] Furthermore, a valve 3012 is fixed at the center of the protrusion 3011. The valve 3012 is a one-way inflation structure, which can automatically close after inflation to maintain the nitrogen pressure inside the pipe. This is existing technology for valve cores and will not be elaborated here. The protective mesh on the inner wall of the storage frame 302 has a discharge port at the bottom that matches the size of the largest diameter sealing cap 301. The lowest sealing cap 301 naturally falls onto the outer arc plate of the corresponding side support 204, awaiting pressing. When the first sealing cap 301 is pushed out, the upper sealing cap automatically falls to fill the gap under gravity, achieving continuous automatic feeding. It should be noted that the diameter of the smallest sealing cap 301 is greater than half the width of the discharge port of the storage frame 302 to prevent the upper sealing cap from accidentally shifting and falling off the discharge port due to friction when the lower sealing cap is pushed out.

[0040] Furthermore, the pushing structure 310 includes a first hydraulic cylinder 311, an intermediate plate 312, several extrusion parts 313, and a second hydraulic cylinder 314. The cylinder body of the second hydraulic cylinder 314 is fixed on the side wall support of the hot melt glue machine 100, and the output shaft is arranged vertically. The top end is fixedly connected to the cylinder body of the first hydraulic cylinder 311, which is used to adjust the vertical height of the first hydraulic cylinder 311 so that the axis of the pushing structure 310 is coaxial with the axis of the current lowest sealing cover 301, which is suitable for sealing operations of heat-treated pipes of different diameters. Specifically, automatic control can be achieved through an industrial camera vision system in conjunction with a PLC control system. This is existing technology and will not be described in detail here.

[0041] Specifically, the output shaft of the first hydraulic cylinder 311 is arranged axially inward along the heat treatment tube 400, and a circular intermediate plate 312 is coaxially fixed at its end. An insertion tube 3121 is coaxially fixed at the center of the inner sidewall of the intermediate plate 312, and the outer diameter of the insertion tube 3121 is adapted to the size of the air inlet of the valve 3012; an air inlet pipe 3122 is connected to the sidewall of the intermediate plate 312, and the air inlet pipe 3122 is connected to the inner cavity of the insertion tube 3121, and is connected to a high-pressure nitrogen gas source for filling the tube with nitrogen.

[0042] In addition, several extrusion parts 313 are evenly distributed in a ring on the inner wall of the intermediate plate 312 for smoothly pushing the sealing cover 301 into place. Each extrusion part 313 consists of a movable rod 3131 and a fixed rod 3132. The outer end of the fixed rod 3132 is fixedly connected to the inner wall of the intermediate plate 312, and the outer end of the movable rod 3131 is inserted into the inner groove of the fixed rod 3132, with the two slidingly engaged. A second spring 3133 is provided in the inner groove of the fixed rod 3132, and the second spring 3133 is arranged between the outer end of the movable rod 3131 and the inner groove wall of the fixed rod 3132.

[0043] During the press-fitting process, the first hydraulic cylinder 311 pushes the intermediate plate 312 inward. The inner end of the movable rod 3131 first contacts the outer end face of the sealing cover 301, pushing the sealing cover 301 along the support plate 204 towards the pipe end and inserting it into place. Subsequently, the first hydraulic cylinder 311 continues to advance, and the movable rod 3131 retracts relative to the fixed rod 3132 and compresses the second spring 3133 until the insertion tube 3121 is fully inserted into the valve 3012. This elastic press-fitting structure can avoid hard contact damage to the sealing cover and the pipe end, while ensuring that the insertion tube can still reliably connect with the valve after press-fitting, achieving stable nitrogen filling.

[0044] The fully automatic nitrogen-filling and pressure-holding capping method for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control in this invention, using the aforementioned fully automatic nitrogen-filling and pressure-holding capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control, includes the following steps: S1. Loading and Centering: Add sufficient sealing caps 301 to the storage boxes 302 on both sides. The sealing caps 301 fall vertically along the limiting groove 3021, and the bottom sealing cap 301 falls onto the outer arc plate of the support plate 204. Place the heat treatment tube 400 to be sealed axially between the front and rear sets of rotating rollers 203. The tube's own weight presses down, causing the support rod 202 to drive the rotating rollers 203 to expand outward to both sides. The pressure plate 2021 compresses the first spring 2013 until the tube's weight and the spring force reach equilibrium, and the heat treatment tube 400 falls at the lowest point of the inner arc plate. At this time, relying on the height difference design of the inner and outer arc plates of the support plate 204, the sealing cap 301 and the heat treatment tube 400 automatically maintain a coaxial state, completing self-centering.

[0045] S2. Position calibration: The PLC system controls the second hydraulic cylinder 314 to adjust the vertical height of the first hydraulic cylinder 311 according to the diameter parameters of the heat treatment tube 400, so that the axis of the pushing structure 310 is completely coaxial with the axis of the bottom sealing cover 301. After calibration, the second hydraulic cylinder 314 is locked to keep the position fixed.

[0046] S3, Cap Fitting: Start the first hydraulic cylinders 311 on both sides to feed synchronously, driving the middle plate 312 and the extrusion piece 313 to move inward. The movable rod 3131 pushes the sealing caps 301 on both sides to move towards each other along the support plate 204, and inserts them into the two ends of the heat treatment tube 400 to complete the initial pressing of the sealing caps.

[0047] S4. Nitrogen charging and pressure holding: After the inner end face of the sealing cap 301 abuts against the pipe end, the first hydraulic cylinder 311 continues to feed, the movable rod 3131 retracts relative to the fixed rod 3132, and the second spring 3133 is compressed until the insertion tube 3121 on the intermediate plate 312 is fully inserted into the valve 3012 in the middle of the sealing cap; the first hydraulic cylinder 311 stops feeding and maintains thrust, the PLC system controls the nitrogen gas source to open, and nitrogen is charged into the heat treatment tube 400 through the air inlet pipe 3122, the insertion tube 3121 and the valve 3012; the pressure sensor inside the tube provides real-time feedback of the pressure value and transmits it to the PLC system. When the pressure reaches the set pressure holding value, the charging stops and the pressure is held for the set time to complete the nitrogen charging and pressure holding process.

[0048] S5. Hot Melt Adhesive Sealing: After nitrogen filling and pressure holding are completed, the first hydraulic cylinder 311 drives the push structure 310 to reset, and the insertion tube 3121 disengages from the valve 3012. The PLC system controls the position adjustment mechanism of the hot melt adhesive machine 100 to adjust the hot melt adhesive nozzle to align with the circumferential joint at the outer end of the sealing cap 301. Then, the servo motor 211 is started, and through the sequential transmission of the drive gear 212, driven gear 213, shaft 214 and track 205, all the rotating rollers 203 are driven to rotate synchronously. Through friction, the heat treatment tube 400 is driven to rotate uniformly around its own axis. At the same time, the hot melt adhesive spraying device is started to uniformly apply hot melt adhesive to the circumferential joint between the outer end of the sealing cap 301 and the outer wall of the heat treatment tube 400. After the coating is completed, the tube body is kept rotating and the drying mechanism is started to dry with hot air. After the hot melt adhesive is completely cured, the fully automatic nitrogen filling and pressure holding sealing operation of the entire heat treatment tube is completed.

[0049] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the specification and its equivalents.

Claims

1. A fully automatic capping device for intelligent heat treatment tubes using hot melt adhesive based on PLC closed-loop control, comprising a hot melt adhesive machine (100) controlled by a PLC system, characterized in that: The hot melt glue machine (100) is provided with a placement component (200) for placing the heat treatment tube (400). The placement component (200) is provided with push cover components (300) on the left and right sides for sealing both ends of the heat treatment tube (400). The placement assembly (200) consists of several bases (201), two support rods (202) hinged to the left and right side walls of the bases (201), and a rotating roller (203) rotatably connected to the inner side wall of the top of the support rod (202). The support rod (202) is provided with a track (205) for driving the rotating roller (203) to rotate. The hot melt glue machine (100) is provided with a drive structure (210). The heat treatment tube (400) is placed between the front and rear support rods (202). After the push cover assembly (300) seals both ends of the heat treatment tube (400), the drive structure (210) is started to drive several tracks (205) to rotate, thereby driving several rotating rollers (203) to rotate synchronously. The heat treatment tube (400) is driven to rotate by the friction between the rotating roller (203) and the heat treatment tube (400). The push-cover assembly (300) consists of a storage frame (302), a sealing cover (301) placed in the storage frame (302), and a push structure (310) for pushing the sealing cover (301) to slide. A support plate (204) is provided between two support rods (202) on the same base (201) to ensure that the heat treatment tube (400) and the sealing cover (301) are placed coaxially. The sealing cover (301) at the bottom of the storage frame (302) is placed on the outer end of the corresponding side support plate (204). After the heat treatment tube (400) is placed in the placement assembly (200), the push structures (310) on both sides are activated to drive the sealing covers (301) at the bottom on both sides to move towards each other and insert into both ends of the heat treatment tube (400) for sealing.

2. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 1, characterized in that: The base (201) has arc-shaped sliding grooves (2011) on both the left and right side walls. The two sliding grooves (2011) on the same base (201) are arranged symmetrically at the center. The center of the sliding groove (2011) is coaxial with the bottom end of the support rod (202). An arc-shaped limiting rod (2012) is fixed concentrically in the sliding groove (2011). An arc-shaped first spring (2013) is sleeved on the limiting rod (2012).

3. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 2, characterized in that: Two support rods (202) on the same base (201) are staggered. A pressure plate (2021) is fixed to the middle of the inner side of the support rod (202). The pressure plate (2021) extends into the corresponding sliding groove (2011). The limiting rod (2012) passes through the corresponding pressure plate (2021) and the two are slidably connected. The first spring (2013) is disposed between the pressure plate (2021) and the bottom surface of the sliding groove (2011).

4. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control, as described in claim 3, is characterized in that: The support plate (204) is composed of an inner arc plate and an outer arc plate fixedly connected. The inner arc plate abuts against the outer wall of the heat treatment tube (400), and the outer arc plate abuts against the outer wall of the sealing cover (301). The front and rear sides of the inner arc plate are connected to the corresponding support rod (202) near the top by elastic bands. The height difference between the outer arc plate and the inner arc plate is equal to the thickness of the sealing cover (301).

5. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 4, characterized in that: The drive structure (210) includes a servo motor (211) fixed at the bottom of the hot melt glue machine (100), an active gear (212) fixed coaxially with the output shaft of the servo motor (211), and a shaft (214) rotatably connected coaxially with the bottom end of several support rods (202). The right end of the shaft (214) is coaxially fixed with a driven gear (213) that meshes with the active gear (212). The shaft (214) passes through several bases (201) and the two are rotatably connected.

6. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 5, characterized in that: The shaft (214) is coaxially fixedly connected to the track wheel at the bottom of the track (205), and the track wheel at the top of the track (205) is coaxially fixed to the central shaft of the corresponding roller (203).

7. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 6, characterized in that: The inner side of the storage frame (302) is a protective net to prevent the sealing cap (301) from detaching from the storage frame (302). A protrusion (3011) is coaxially fixed in the middle of the outer wall of the sealing cap (301). A limiting groove (3021) adapted to the size of the protrusion (3011) is provided in the middle of the outer wall of the storage frame (302). The width of the left and right inner walls of the storage frame (302) is equal to the left and right length of the sealing cap (301). An air valve (3012) for inflation is fixed in the middle of the protrusion (3011).

8. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 7, characterized in that: The pushing structure (310) includes a first hydraulic cylinder (311), an intermediate plate (312) coaxially fixed with the output shaft of the first hydraulic cylinder (311), and a number of extrusion parts (313) regularly distributed in a ring on the inner sidewall of the intermediate plate (312). The inner sidewall of the intermediate plate (312) is coaxially fixed with an insertion tube (3121). The sidewall of the intermediate plate (312) is provided with an air inlet pipe (3122) for supplying nitrogen to the insertion tube (3121). A second hydraulic cylinder (314) is fixed below the first hydraulic cylinder (311) for adjusting the vertical height of the first hydraulic cylinder (311) so that it is coaxial with the protrusion (3011).

9. The fully automatic capping equipment for hot melt adhesive intelligent heat treatment tubes based on PLC closed-loop control as described in claim 8, characterized in that: The extrusion member (313) consists of a movable rod (3131) and a fixed rod (3132). The outer end of the movable rod (3131) is inserted into the corresponding fixed rod (3132) and the two are slidably connected. A second spring (3133) is provided in the fixed rod (3132). The second spring (3133) is located between the outer end of the movable rod (3131) and the inner groove wall of the fixed rod (3132). The outer end of the fixed rod (3132) is fixed to the inner side wall of the intermediate plate (312).

10. A fully automatic nitrogen-filling and pressure-holding capping method for intelligent heat treatment tubes using hot melt adhesive based on PLC closed-loop control, employing the fully automatic nitrogen-filling and pressure-holding capping equipment for intelligent heat treatment tubes using PLC closed-loop control as described in claim 9, characterized in that... Includes the following steps: S1. Add an appropriate number of sealing caps (301) to the storage box (302), place the heat treatment tube (400) between the front and rear sets of rotating rollers (203), and the gravity of the heat treatment tube (400) presses down to make the support rod (202) and the rotating roller (203) expand outward and press down to the bottom of the middle of the inner arc plate until the gravity of the heat treatment tube (400) is balanced with the elastic force of all the first springs (2013). The bottom sealing cap (301) abuts against the outer arc plate and automatically falls on the bottom of the middle of the outer arc plate under its own gravity. Since the difference between the outer diameter of the sealing cap (301) and the outer diameter of the heat treatment tube (400) is equal to the thickness of the sealing cap (301), the sealing cap (301) and the heat treatment tube (400) are in a coaxial state at this time. S2. After the heat treatment tube (400) is placed and balanced, the second hydraulic cylinder (314) is started to adjust the position of the first hydraulic cylinder (311) to be coaxial with the bottom sealing cover (301). Then the second hydraulic cylinder (314) is closed, and the first hydraulic cylinder (311) is started to drive the intermediate plate (312) and the extrusion piece (313) to push the sealing covers (301) on both sides to move towards each other and be inserted into the two ends of the heat treatment tube (400). S3. When the inner surface of the sealing cap (301) is inserted into the heat treatment tube (400) and abuts against the tube end, the first hydraulic cylinder (311) continues to drive the intermediate plate (312) to move inward, so that the movable rod (3131) and the fixed rod (3132) slide relative to each other and squeeze the second spring (3133) until the insertion tube (3121) is fully inserted into the valve (3012). Then the first hydraulic cylinder is closed and nitrogen is charged into the valve (3012) through the air inlet pipe (3122) to maintain pressure. S4. After inflation is completed, stop inflation and start the position adjustment device of the hot melt glue machine (100) to adjust the hot melt glue nozzle to correspond to the circumferential joint position of the outer end of the sealing cover (301). Then start the servo motor (211) to drive all the rotating rollers (203) to rotate synchronously through the sequential transmission of the active gear (212), driven gear (213), shaft (214) and track (205). Then, the friction between the rotating rollers (203) and the heat treatment tube (400) drives the heat treatment tube (400) to rotate. At the same time, start the glue spraying device of the hot melt glue machine (100) to spray glue between the outer end of the sealing cover (301) and the outer wall of the heat treatment tube (400) for sealing. After the glue spraying is completed, dry it to complete the nitrogen filling and pressure sealing.

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