Liquid filling machine and control method thereof

Abstract

The invention relates to the technical field of liquid filling, in particular to a liquid filling machine and a control method thereof.The liquid filling machine comprises a workbench used for bearing installation of stations needed by liquid filling, and further comprises an annular conveying line arranged on the workbench and configured to transfer secondary throwing pipes to all the stations for treatment; the liquid injection mechanism is configured to inject liquid into the secondary throwing pipe through a filling needle; the hot melting mechanism is configured to perform hot melting softening treatment on the pipe orifice; the sealing mechanism is configured to clamp, seal and shape the softened pipe orifice; the control unit is configured to control the annular conveying line to run according to a preset rhythm so as to sequentially convey the secondary polishing pipes to all the stations in a stepping mode, and all the stations are controlled in a coordinated mode to execute corresponding machining operation on the secondary polishing pipes; by adopting the annular conveying line layout, the material transfer path is effectively shortened, and compared with the existing linear layout, the flexibility of station expansion is remarkably improved, so that the production line can conveniently increase and decrease stations according to requirements.

Description

Technical Field

[0001] This invention relates to the field of liquid filling technology, and in particular to a liquid filling machine and its control method. Background Technology

[0002] Single-use sterile packaging tubes are widely used in pharmaceuticals, high-end cosmetics, and other fields. To improve production efficiency, common single-use tubes are usually made by connecting multiple micro-plastic tubes into a row through a thermoplastic process to form a tube array structure. The production process typically includes multiple steps such as feeding, filling, tube end heat sealing, sealing and shaping, and unloading. Existing technologies already contain optimized solutions for individual steps. For example, Chinese Patent Publication No. CN218968840U discloses a tube array filling mechanism, which, through a unique needle structure and liquid path design, helps to achieve accurate quantitative filling and reduce droplet residue. Another example is Chinese Patent Publication No. CN218965498U, which discloses a tube array cutting mechanism that can effectively remove excess sealing edges from the tube array. These solutions have achieved good results in solving their respective specific technical problems.

[0003] However, integrating multiple high-performance, single-function mechanisms into a complete, coherent automated production line presents significant challenges. Current common integration solutions often employ a linear layout, which is inflexible in terms of workstation expansion, has long material transfer paths, and introduces waiting times between mechanisms, limiting further improvements in overall production cycle time. More importantly, the existing equipment's control systems lack sufficient coordination, making it difficult to achieve precise synchronization and conditional interlocking of the actions of individual mechanisms. This can lead to the following problems: insufficient coordination of the timing of actions between processing stations (such as filling, hot melting, and sealing), resulting in limited equipment production cycle time and low overall efficiency; waiting times during transfers between stations, preventing efficient parallel operations. Furthermore, the control logic of existing equipment is too rigid and cannot flexibly respond to accidental changes in the incoming material status. For example, if a secondary ejector tube is missing at a certain station, the equipment may still perform a no-load operation, wasting energy and potentially accelerating wear on the mechanisms. To address these issues, existing technologies urgently need improvement. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a liquid filling machine and its control method.

[0005] In a first aspect, the present invention provides a liquid filling machine, including a workbench for supporting the installation of workstations required for liquid filling, and further comprising: The circular conveyor line, set on the workbench, is configured to transfer the secondary tubes to various workstations for processing. The liquid injection mechanism is configured to inject liquid into the secondary ejection tube via a filling needle. The heat fusion mechanism is configured to perform heat fusion softening treatment on the nozzle; The sealing mechanism is configured to clamp and shape the softened pipe opening; The control unit is connected in communication with the circular conveyor line and each station on the workbench. It is configured to control the circular conveyor line to run at a preset pace to sequentially transport the secondary tubes to each station and coordinate the corresponding stations to perform corresponding processing operations on the secondary tubes.

[0006] Preferred options also include: The cutting mechanism is used to cut off the excess sealing edge of the secondary tube after it has been clamped and shaped; The unloading mechanism is used to remove the processed secondary tubes from the circular conveyor line.

[0007] Preferably, the annular conveyor line includes: A ring seat is fixedly installed on the workbench, and a ring guide rail is fixedly installed on the ring seat; Multiple transmission seats are driven by chain drive to slide along the trajectory of an annular guide rail. Each transmission seat is provided with a mold seat for inserting the secondary throwing tube.

[0008] Preferably, the bottom of the transmission seat is symmetrically and rotatably equipped with first rollers, and the symmetrically arranged first rollers roll along the guide grooves on both sides of the annular guide rail.

[0009] Preferably, the circular conveyor line further includes a positioning component, which is used to limit the position of the transmission seat when the transfer stops. The positioning component includes: Multiple positioning pins are rotatably mounted on the side walls of multiple transmission seats. A pair of support columns are symmetrically mounted on the bottom of each transmission seat. Two sets of support members are symmetrically fixed on both sides of the annular seat near the injection mechanism. A second roller is rotatably mounted on the support member. The second roller is used to support the bottom of the support column. Multiple fasteners are fixedly installed on the side wall of the annular seat. A positioning plate is slidably connected to the fastener. The positioning plate has a positioning groove that matches the positioning pin. A first pusher is fixedly installed on the side wall of the fastener for pushing the positioning plate to move vertically along the fastener.

[0010] Preferably, the hot-melt mechanism includes: A heating cover is disposed above the conveying track of the circular conveyor line. An installation cover is fixedly installed inside the heating cover. Both the heating cover and the installation cover are provided with heat dissipation holes. Multiple heating elements are symmetrically installed on both sides of the inner wall of the mounting cover; Two fixing plates are symmetrically fixed on the inner wall of the heating cover, and a heating space is left between the two fixing plates for the secondary throwing tube port to pass through after liquid injection.

[0011] Preferably, the sealing mechanism includes: The mounting frame is fixedly installed on the workbench, and a support frame is mounted on the mounting frame via a lifting assembly; Two movable seats are symmetrically arranged inside the mounting frame via a guide assembly. A first connecting seat is installed on the side wall of each movable seat, and a second connecting seat is installed on the first connecting seat. Two clamping blocks are respectively set on one side of the opposite face of the two second connecting seats, and multiple split-type sealing cavities are equally spaced on the opposite sides of the two clamping blocks; Two second pushers are symmetrically mounted on the side wall of the mounting frame, and are used to drive the two movable seats to move towards each other or away from each other along the guide trajectory of the guide assembly; The lifting assembly includes: Two sliders are symmetrically slidably connected to both sides of the mounting bracket; A connecting plate, which is fixedly mounted on the top of the mounting frame; The threaded rod is threadedly connected to the top of the mounting bracket via a threaded sleeve, and the lower end of the threaded rod is rotatably connected to the top of the connecting plate. A handwheel is fixedly installed at the upper end of the threaded rod.

[0012] Preferably, the guiding assembly includes two guide rods, both of which are fixedly installed on the inner wall of the support frame. Each movable seat has a slide at both ends, and the slide slides along the surface of the guide rod.

[0013] Preferably, the sealing cavity includes a first sealing surface and a second sealing surface arranged sequentially.

[0014] Preferably, the sealing mechanism further includes a vacuum-assisted forming component, configured to use negative pressure to fit the nozzle material into the sealing mold cavity to form a specified full shape.

[0015] Preferably, the vacuum-assisted forming assembly includes: Two cavities are respectively opened inside the two clamping blocks. Each first sealing surface has multiple first connecting holes that communicate with the interior of the cavity. Each second sealing surface has a second connecting hole that communicates with the interior of the cavity at its internal corner. Two vacuum pumps are connected to the inside of two cavities via connecting pipes, and are used to evacuate the inside of the cavities.

[0016] Preferably, the control unit includes: The controller is used to control the operation of the liquid filling machine; The station status sensor is connected to the controller signal and is set at each processing station to detect whether the secondary tube is present at that station. The positioning sensor, which is mounted on the worktable via a cross slide and connected to the controller signal, is configured to trigger a signal when it senses the positioning pin on the circular conveyor line, causing the circular conveyor line to stop running for a preset time and control the corresponding station status sensor to restart the conveyor after detecting the secondary tube throwing station, thereby realizing the intermittent step conveying of the mold base at each station.

[0017] Secondly, a control method for a liquid filling machine, wherein the control method of the controller includes the following steps: Receives trigger signals from the positioning sensor and generates control information; Control information is sent to the circular conveyor line to control the circular conveyor line to stop for a preset time, while all mold holders are simultaneously positioned at their respective destination stations. Check the detection status of the station status sensors at each workstation to confirm whether the secondary tube has been accurately positioned. A start command is issued to the workstation where the workstation status sensor detects a secondary tube being thrown.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention, by employing a circular conveyor line layout, effectively shortens the material transfer path. Compared to the existing linear layout, it significantly improves the flexibility of workstation expansion, allowing the production line to easily add or remove workstations as needed. The circular conveyor line transports the secondary tubes to various workstations for processing. In conjunction with core processing units such as the liquid injection mechanism, hot-melt mechanism, and sealing mechanism, it achieves full automation from filling to sealing and shaping.

[0019] More importantly, this invention introduces a control unit that communicates with the circular conveyor line and each workstation on the workbench. This control unit is configured to control the circular conveyor line to operate at a preset pace, sequentially transporting the secondary tubes to each workstation and coordinating the processing operations performed on the tubes at each workstation. This collaborative control mechanism solves the problem of insufficient coordination in existing equipment control systems, achieving precise synchronization and conditional interlocking of the action sequences of each processing workstation. This avoids waiting time between workstations and significantly improves the overall production pace and efficiency. Furthermore, the control unit can flexibly respond to changes in the incoming material status. For example, it can detect the presence of the secondary tube at its workstation using a workstation status sensor, avoiding the drawback of existing equipment performing empty operations when the secondary tube is missing. This reduces energy waste and mechanical wear, and improves the intelligence and operational reliability of the equipment. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the installation structure above the workbench of the present invention; Figure 3 For the present invention Figure 2 Schematic diagram of the structure at point A in the middle; Figure 4 This is a schematic diagram of the positioning component structure of the present invention; Figure 5 This is a schematic diagram of the installation structure of the annular seat of the present invention; Figure 6 This is a schematic diagram of the sealing mechanism of the present invention; Figure 7 This is a schematic diagram of the connection between the guide rod and the slide block of the present invention; Figure 8 This is a schematic diagram of the clamping block structure of the present invention; Figure 9 For the present invention Figure 8 Enlarged structural diagram at point B; Figure 10 This is a schematic diagram showing the connection between the positioning sensor and the cross slide of the present invention; Figure 11 This is a flowchart of the control method of the present invention.

[0021] In the diagram: 1. Workbench; 2. Annular seat; 3. Annular guide rail; 4. Transmission seat; 5. First roller; 6. Mold seat; 7. Positioning pin; 8. Support component; 9. Liquid injection mechanism; 10. Cutting mechanism; 11. Second roller; 12. Fixing component; 13. Positioning plate; 1301. Positioning groove; 14. First pushing component; 15. Heating cover; 16. Mounting cover; 17. Heating tube; 18. Fixing plate; 19. Mounting bracket; 20. Support frame; 21. Moving seat; 22. Clamping block; 23. Sealing mold cavity; 2301. First sealing surface; 2302. Second sealing surface; 24. Second pushing component; 25. Slider; 26. Connecting plate; 27. Threaded rod; 28. Cavity; 29. ​​Positioning sensor; 30. Cross slide; 31. Guide rod; 32. Slide seat. Detailed Implementation

[0022] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0023] Traditional secondary tube throwing production lines suffer from inflexibility in expanding workstations and long material transfer paths, leading to unnecessary waiting times between mechanisms and severely limiting further improvements in overall production cycle time. For example, if a secondary tube at a certain workstation is missing, the equipment may still perform an empty operation, wasting energy and potentially accelerating wear and tear on the mechanisms. Failure to address these issues results in poor equipment coordination, insufficient timing coordination between processing stations, low overall efficiency, and an inability to achieve efficient parallel operations. Furthermore, the rigid control logic cannot flexibly respond to occasional changes in the incoming material status, further reducing the production line's flexibility.

[0024] For example, consider a traditional linear secondary tube filling production line. After filling at the liquid injection station, the secondary tubes need to travel a long transport path to reach the hot-melt station. If the hot-melt station is currently processing the previous batch of tubes, the filled tubes must wait, causing production to stall. Furthermore, if a tube at a station fails to reach its correct position, and the control system fails to detect this anomaly in time, that station will still execute its preset operation, wasting processing time and potentially causing unnecessary wear and tear on the equipment. These problems collectively lead to low production efficiency and resource waste.

[0025] like Figures 1 to 10 The liquid filling machine shown includes a workbench 1 for supporting the installation of the workstations required for liquid filling, and also includes: The circular conveyor line, set on workbench 1, is configured to transfer the secondary tubes to various workstations for processing. The circular conveyor line adopts a circular layout, which allows the secondary tubes to be circulated between multiple workstations. Each workstation can process the secondary tubes independently. Compared with the traditional linear conveyor line, it can effectively shorten the material transfer path, reduce waiting time, and support parallel operation of multiple workstations, thereby significantly improving production efficiency. The liquid injection mechanism 9 is configured to inject liquid into the secondary throwing tube through a filling needle. The liquid injection mechanism 9 is the core of the filling process and is responsible for injecting the liquid into the secondary throwing tube accurately and quantitatively. The liquid injection mechanism 9 adopts the liquid injection equipment in the prior art, which may specifically include a high-precision peristaltic pump and a stainless steel filling needle. The accuracy of liquid injection and residue control are optimized.

[0026] The hot-melt mechanism is configured to perform a hot-melt softening treatment on the pipe opening; before sealing, the pipe opening of the secondary-thrown pipe needs to undergo a hot-melt treatment to bring it to a molten or semi-molten state so that the subsequent sealing operation can be carried out smoothly and the sealing quality can be ensured. The sealing mechanism is configured to clamp and shape the softened pipe opening; after the pipe opening is softened, the sealing mechanism clamps and shapes it to form a specified sealing shape, ensuring the sealing and integrity of the secondary pipe. The control unit is connected in communication with the circular conveyor line and each station on the workbench 1. It is configured to control the circular conveyor line to run at a preset pace to sequentially transport the secondary tubes to each station and coordinate the corresponding stations to perform corresponding processing operations on the secondary tubes.

[0027] The control unit refers to the central control system that is connected to the circular conveyor line and each workstation on the workbench 1. Specifically, it can be implemented using a programmable logic controller combined with a human-machine interface. For example, a customized control software based on an industrial computer or a distributed control system can coordinate the actions of each mechanism through a fieldbus. It is configured to control the circular conveyor line to run at a preset pace to sequentially transport the secondary tubes to each workstation and trigger the corresponding workstation to perform processing operations only when the secondary tubes are in place.

[0028] Compared with existing technologies, the liquid filling machine of this embodiment has significant advantages. Traditional linear layouts have limitations in terms of workstation expansion and material transfer, while the circular conveyor line used in this application effectively solves these problems. The circular conveyor line shortens the material transfer path and reduces waiting time between workstations, thereby improving overall production efficiency. Furthermore, the introduction of the control unit greatly enhances the coordination between workstations, enabling precise action synchronization and conditional interlocking. For example, the control unit can determine whether the secondary tube is in place based on information detected by the workstation status sensor, thereby avoiding erroneous operation at empty workstations and reducing energy waste and mechanical wear. This intelligent control method significantly improves the flexibility and reliability of the equipment.

[0029] When using this liquid filling machine, the secondary tube is first placed on the mold seat 6 of the circular conveyor line. The control unit drives the circular conveyor line to run at a preset pace, sequentially conveying the secondary tube to each processing station. When the secondary tube reaches the injection mechanism 9, the filling needle of the injection mechanism 9 descends to inject liquid into the secondary tube. After completion, the needle rises. The injection mechanism 9 can use dual-station injection to speed up the injection speed. Subsequently, the secondary tube is conveyed to the heat-melting mechanism, which heats and softens the tube opening to make it melt or semi-melt. Then, the secondary tube is conveyed to the sealing mechanism, which clamps and shapes the softened tube opening to form a specified sealing shape. Throughout the process, the control unit monitors the status of each station in real time and coordinates the actions of each mechanism to ensure that the secondary tube flows efficiently and accurately between each station. While one station (such as liquid injection) is performing processing, other stations (such as heat melting and sealing) are also simultaneously processing the secondary tubes at their respective stations. This parallel processing mode is the key to efficient production. In this way, this liquid filling machine can automate, efficiently and in parallel process such as secondary tube filling, heat melting and sealing, which significantly improves production efficiency and product quality.

[0030] As one embodiment of the present invention, it further includes: The cutting mechanism 10 is used to cut off the excess sealing edge of the secondary tube after it has been clamped and shaped; The unloading mechanism is used to remove the processed secondary tubes from the circular conveyor line.

[0031] In practical applications, the cutting mechanism 10 refers to a special device for physically removing excess sealing edges. It can be implemented using existing technologies such as mold-closing cutting components, laser cutting modules, or ultrasonic cutting units. Its purpose is to accurately remove residual pipe material after sealing, avoiding edge deformation or contamination caused by friction during subsequent transfer. The unloading mechanism can be understood as an automated material transfer structure. It can be implemented using robotic arm gripping components, pneumatic push rod picking devices, or conveyor belt collaborative clamping mechanisms. Its purpose is to remove qualified finished products in a timely manner based on workstation status feedback, preventing production interruptions caused by material accumulation on the circular conveyor line.

[0032] The solution proposed in this application effectively solves the problems of uneven sealing edges and the need for manual removal after processing in the basic solution by adding a cutting mechanism 10 and a feeding mechanism. Specifically, after the secondary tube is clamped and shaped by the sealing mechanism, it is conveyed to the cutting mechanism 10. Under the coordinated control of the control unit, the cutting mechanism 10 precisely cuts off the excess sealing edges of the secondary tube, thereby ensuring the flatness and aesthetics of the tube opening edge. Subsequently, the secondary tube with the edge-cutting process is conveyed to the feeding mechanism. After receiving the instruction from the control unit, the feeding mechanism accurately removes the processed secondary tube from the circular conveyor line and places it in the preset collection area or the entrance of the next process, thereby realizing the automation and continuity of the entire filling production line.

[0033] In some preferred embodiments, the cutting mechanism 10 can be configured as a pair of scissor-type blades, which are opened and closed by a cylinder. When the secondary tube is conveyed to the area below the cutting mechanism 10, the cylinder drives the blades to close, cutting off the excess edge. The unloading mechanism can be a vacuum suction cup robot. When the secondary tube arrives at the unloading station, the robot descends, the suction cup picks up the secondary tube, and then the robot rises and rotates to a designated position, releasing the secondary tube into a collection box.

[0034] As one embodiment of the present invention, the circular conveyor line includes: An annular seat 2 is fixedly installed on the workbench 1, and an annular guide rail 3 is fixedly installed on the annular seat 2. Multiple transmission seats 4 are driven by chain drive to slide along the trajectory of the annular guide rail 3. Each transmission seat 4 is provided with a mold seat 6 for inserting the secondary throwing tube. The bottom of the transmission seat 4 is symmetrically mounted with first rollers 5, which roll along the guide grooves on both sides of the annular guide rail 3.

[0035] In practical applications, the ring seat 2 refers to the basic structure that provides rigid support for the ring conveyor line. It can be made of cast iron or welded steel structure, and its purpose is to ensure the geometric stability of the ring guide rail 3 and avoid structural deformation caused by equipment vibration or load changes. The ring guide rail 3 can be understood as a guiding component that defines a precise ring motion trajectory. It can be made of closed ring steel rail or profile bending structure, and its purpose is to eliminate the cumulative error caused by the long path in the traditional straight layout and provide a geometric reference for the transfer of the secondary tube. The transmission seat 4 refers to the moving unit that carries the secondary tube and moves along the guide rail. It can be made of aluminum alloy slider or engineering plastic bracket, and its purpose is to achieve chain drive. To achieve uniform drive force transmission and avoid the slippage defect of belt drive; chain drive can be understood as the power transmission mechanism that drives the synchronous movement of the drive seat 4. It can be implemented by using a roller chain with sprockets or a toothed belt drive system. The purpose is to ensure uniform transmission of drive force and synchronous movement; mold seat 6 refers to a special clamping structure for fixing the secondary tube. It can be implemented by using a cylindrical slot or an elastic clamp structure. The purpose is to prevent the secondary tube from falling off or shifting during transportation by matching the shape; the first roller 5 refers to the guide element that constrains the movement direction of the drive seat 4. It can be implemented by using a steel roller or nylon roller supported by a bearing. Its function is to reduce friction and enable the object to move more smoothly.

[0036] Specifically, the solution of this application provides a clear running trajectory for the transmission seat 4 by fixing an annular seat 2 on the workbench 1 and setting an annular guide rail 3 on the annular seat 2. The first roller 5, in cooperation with the guide groove of the annular guide rail 3, effectively constrains the movement trajectory of the transmission seat 4, preventing lateral deviation or longitudinal swaying. Simultaneously, the rotation of the first roller 5 reduces the friction between the transmission seat 4 and the annular guide rail 3, making its movement smoother and more stable. Multiple transmission seats 4 slide along the annular guide rail 3 via chain drive. Each transmission seat 4 is equipped with a mold seat 6 for inserting the secondary discharge tube. Thus, the annular conveyor line can achieve stable and continuous transport of the secondary discharge tube, and the mold seat 6 effectively fixes the secondary discharge tube, ensuring precise positioning during processing at each station, thereby improving the overall operating efficiency and processing accuracy of the filling machine. This structural combination ensures that the position of the secondary discharge tube is highly accurate when the transport stops, providing a precise alignment basis for the operating points of the injection mechanism 9, the hot-melt mechanism, and other stations, thereby ensuring precise synchronization of each process.

[0037] In some preferred embodiments, the annular seat 2 can be made of high-strength aluminum alloy to ensure its structural stability and corrosion resistance, and is bolted to the worktable 1. The annular guide rail 3 can be made of precision-machined stainless steel with a hardened surface to reduce friction and improve wear resistance, ensuring smooth sliding of the transmission seat 4. The transmission seat 4 can be made of engineering plastic or lightweight metal to reduce overall weight and is connected to the drive motor via a chain to achieve precise stepping or continuous rotation. The mold seat 6 can be customized according to the external dimensions of the secondary tube, using elastic materials or a design with a clamping mechanism to ensure that the secondary tube can be firmly inserted and removed. For example, the mold seat 6 can be designed with a tapered inner cavity, allowing the secondary tube to be inserted and stably fixed by gravity or slight pressure.

[0038] In one embodiment of the present invention, the circular conveyor line further includes a positioning component, which is used to limit the position of the transmission seat 4 when the transfer stops. The positioning component includes: Multiple positioning pins 7 are rotatably mounted on the side walls of multiple transmission seats 4. A pair of support columns are symmetrically mounted on the bottom of each transmission seat 4. Two sets of support members 8 are symmetrically fixed on both sides of the annular seat 2 near the injection mechanism 9. A second roller 11 is rotatably mounted on the support member 8. The second roller 11 is used to support the bottom of the support column. Multiple fasteners 12 are fixedly installed on the side wall of the annular seat 2. A positioning plate 13 is slidably connected to the fastener 12. The positioning plate 13 has a positioning groove 1301 that is compatible with the positioning pin 7. A first pusher 14 is fixedly installed on the side wall of the fastener 12 to push the positioning plate 13 to move vertically along the fastener 12.

[0039] Specifically, the positioning pin 7 refers to the mechanical component installed on the side wall of the transmission seat 4 for position locking. It can be implemented using a rotatable pin structure, such as by connecting through bearings or hinges, so that the positioning pin 7 can rotate freely with the transmission seat 4 without motion interference during the operation of the circular conveyor line. Its purpose is to avoid structural interference during continuous operation of the conveyor line. The support column refers to the support structure symmetrically arranged at the bottom of the transmission seat 4. It can be implemented using rigid metal columns to evenly distribute support points and reduce the shaking of the transmission seat 4 at the moment of stopping. Its purpose is to enhance overall stability. The second roller 11 refers to the rolling support element set on the support member 8. It can be implemented using a roller with a sealed bearing, using rolling friction instead of sliding friction to suppress vibration transmission. Its purpose is to ensure that the transmission seat 4 at the liquid injection station is in a stable position. During the liquid filling process, the system should remain stable to avoid vibration of the transmission seat 4 due to filling pressure. The positioning plate 13 refers to a limiting plate with a positioning groove 1301, which can be implemented by a steel plate slidingly connected to the fixing part 12 via a guide rail. It is used to exit the working area during the non-positioning stage, and its purpose is to improve the adaptability of the system. The positioning groove 1301 refers to a groove structure on the positioning plate 13 that matches the shape of the positioning pin 7. It can be implemented by a V-shaped or rectangular groove structure to eliminate small gaps and form error-free locking. Its purpose is to ensure the absolute positioning accuracy of the secondary tube at the work station. The first pushing part 14 refers to the actuator that drives the positioning plate 13 to move. It can be implemented by a pneumatic cylinder or an electric push rod. It automatically triggers the positioning action according to the stop rhythm of the circular conveyor line, and its purpose is to achieve precise synchronization between the limiting operation and the conveying rhythm.

[0040] Specifically, in the solution of this application, when the circular conveyor line drives the transmission seat 4 to move to the vicinity of the predetermined work position, the positioning sensor 29 senses the positioning pin 7 on the transmission seat 4 and triggers a signal to the control unit. The control unit controls the circular conveyor line to decelerate and stop. At the same time, the control unit controls the first pusher 14 to push the positioning plate 13 upward. The positioning groove 1301 on the positioning plate 13 cooperates with the positioning pin 7 to achieve precise positioning of the transmission seat 4. Meanwhile, the second roller 11 on the support member 8 supports the bottom of the support column, further improving the stability of the transmission seat 4. Through the cooperation of the positioning pin 7 and the positioning groove 1301, the cumulative error of the transmission seat 4 when it stops can be effectively eliminated, ensuring that each transmission seat 4 can accurately stop at the predetermined work position, thereby ensuring the processing accuracy and quality of subsequent processes.

[0041] As one embodiment of the present invention, the hot-melt mechanism includes: A heating cover 15 is positioned above the conveying track of the circular conveyor line. An installation cover 16 is fixedly installed inside the heating cover 15. Both the heating cover 15 and the installation cover 16 are provided with heat dissipation holes. Multiple heating tubes 17 are symmetrically installed on both sides of the inner wall of the mounting cover 16; Two fixing plates 18 are symmetrically fixed on the inner wall of the heating cover 15, and a heating space is left between the two fixing plates 18 for the secondary throwing tube port to pass through after liquid injection.

[0042] Specifically, the heating cover 15 refers to the heat protection structure covering the circular conveyor line track. It can be made of stainless steel sheet metal or high-temperature resistant ceramic material. Its purpose is to completely enclose the area of ​​the secondary tube opening in the heating environment to avoid heat loss or local cooling due to exposure. The mounting cover 16 refers to the secondary support structure built into the heating cover 15. It can be designed as a grid or honeycomb to optimize heat flow distribution. Its purpose is to strengthen the internal support strength and form a double-layer heat buffer space. The heat dissipation holes refer to the ventilation holes opened on the surface of the cover. They can be configured as a circular array or strip slits. Their purpose is to dynamically adjust the internal air pressure and temperature according to the principle of thermal expansion to prevent excessive heat accumulation and material deterioration. The heating tube 17 refers to the heating element that provides the heat source. It can be an infrared radiation tube or a resistance wire heating tube. Its purpose is to allow heat to penetrate evenly from the circumference of the tube opening through symmetrical radiation, adapting to slight deviations during the conveying process. The fixing plate 18 refers to the guide component that forms the heating channel. It can be made of heat-resistant alloy plate and equipped with a fine-tuning mechanism. Its purpose is to accurately guide the tube opening through the path and concentrate the heat energy on the tube opening area.

[0043] Specifically, the heating cover 15 completely covers the entire circular conveyor line track, ensuring that the pipe opening area remains in a closed heating environment during the step-by-step conveying process. The double-layer structure formed by the heating cover 15 and the mounting cover 16 optimizes the heat flow path through the space between the two covers, reducing the impact of turbulence on the uniformity of heat melting. The heat dissipation holes work together to dynamically regulate the internal air pressure and temperature, ensuring the consistency of the degree of heat melting and softening. Multiple heating tubes 17 are symmetrically installed on both sides of the inner wall of the mounting cover 16, allowing heat to penetrate evenly from the circumference of the pipe opening based on the principle of symmetrical radiation. The narrow heating space formed by the two fixing plates 18 precisely guides the pipe opening through the path through physical constraints, concentrating the heat energy on the pipe opening area rather than the pipe body. The above structures work together to ensure uniform heat melting and precise temperature control of the pipe opening during continuous conveying.

[0044] As one embodiment of the present invention, the sealing mechanism includes: Mounting frame 19 is fixedly mounted on workbench 1, and a support frame 20 is mounted on mounting frame 19 via lifting assembly; Two movable seats 21 are symmetrically arranged inside the mounting frame 19 via a guide assembly. A first connecting seat is installed on the side wall of the movable seat 21, and a second connecting seat is installed on the first connecting seat. Two clamping blocks 22 are respectively set on one side of the opposite face of the two second connecting seats, and multiple split-type sealing mold cavities 23 are equally spaced on the opposite sides of the two clamping blocks 22; Two second pushers 24 are symmetrically mounted on the side wall of the mounting bracket 19, and are used to drive the two movable seats 21 to move towards each other or away from each other along the guide trajectory of the guide assembly.

[0045] Specifically, the solution of this application adjusts the height of the support frame 20 by using a lifting component to precisely align the clamping block 22 with the opening of the secondary tube. When the circular conveyor line stops and the secondary tube is positioned at the sealing station, the second pusher 24 drives the moving seat 21 to move towards each other along the guide component trajectory, causing the clamping block 22 to close, so that the split sealing mold cavity 23 covers the tube opening, ensuring that the tube opening material is compacted at the corner of the sealing mold cavity 23, thereby achieving the sealing operation.

[0046] As one embodiment of the present invention, the lifting assembly includes: Two sliders 25 are symmetrically connected to both sides of the mounting bracket 19; Connecting plate 26, the connecting plate 26 is fixedly installed on the top of the mounting bracket 19; The threaded rod 27 is threadedly connected to the top of the mounting bracket 19 via a threaded sleeve, and the lower end of the threaded rod 27 is rotatably connected to the top of the connecting plate 26. A handwheel is fixedly installed at the upper end of the threaded rod 27.

[0047] Specifically, the handwheel surface of the threaded rod 27 is provided with anti-slip texture. When the operator rotates the handwheel, the rotational motion of the threaded rod 27 is converted into the vertical displacement of the support frame 20. Combined with the guiding effect of the slider 25, the height can be precisely adjusted to adapt to the dimensional tolerances of different batches of tubes.

[0048] In one embodiment of the present invention, the guide assembly includes two guide rods 31, both of which are fixedly installed on the inner wall of the support frame 20. Each movable seat 21 has a slide 32 at both ends, and the slide 32 slides along the surface of the guide rod 31.

[0049] Among them, the guide rod 31 serves as a guide mechanism for the movement of the slide 32. Its main function is to ensure that the moving seat 21 can move smoothly along a predetermined straight path. The guide rod 31 is usually made of high-strength, wear-resistant materials, such as hard alloy or surface-treated steel, to ensure its service life and accuracy. The slide 32 usually adopts a sliding bearing or rolling bearing structure to reduce frictional resistance and improve the smoothness and response speed of the movement.

[0050] In this application, by fixing two guide rods 31 on the inner wall of the support frame 20 and allowing the movable seat 21 to slide along the guide rods 31 via the slide block 32, the movement trajectory of the movable seat 21 is precisely guided. This structural design can effectively reduce the shaking and offset of the movable seat 21 during movement, ensuring that the clamping block 22 can accurately clamp and seal the opening of the secondary throwing tube, thereby improving the quality and consistency of the sealing.

[0051] In one embodiment of the present invention, the sealing cavity 23 includes a first sealing surface 2301 and a second sealing surface 2302 arranged sequentially.

[0052] By setting the first sealing surface 2301 and the second sealing surface 2302, it is convenient to press the shape into the required style, enhancing the aesthetics of the seal. Compared with traditional sealing methods, this application, through the optimized design of the first sealing surface 2301 and the second sealing surface 2302, can better adapt to secondary firing tubes of different materials and specifications, improving the versatility and flexibility of the seal.

[0053] As one embodiment of the present invention, the sealing mechanism also includes a vacuum-assisted forming component, which is configured to use negative pressure to make the tube end material fit into the sealing mold cavity 23 to form a specified full shape. In practical applications, the vacuum-assisted forming component refers to an auxiliary structure that achieves material shaping through negative pressure. It can be implemented by integrating a negative pressure channel network inside the clamping block 22 or by setting a distributed micropore adsorption array. Specifically, it can be configured as a cavity system connected to a negative pressure source. Its purpose is to overcome the springback effect of the tube end material during the cooling and shaping process and ensure that the material uniformly fills the contour of the sealing mold cavity 23.

[0054] Vacuum-assisted forming components include: Two cavities 28 are respectively opened inside the two clamping blocks 22. Each first sealing surface 2301 has multiple first connecting holes that communicate with the interior of the cavity 28. Each second sealing surface 2302 has a second connecting hole that communicates with the interior of the cavity 28 at its internal corner. Two vacuum pumps are connected to the inside of the two cavities 28 through connecting pipes, respectively, for evacuating the inside of the cavities 28.

[0055] In this application, after the clamping block 22 completes the clamping of the tube opening through relative movement, a vacuum pump is used to evacuate the cavity 28. This allows the first sealing surface 2301 and the second sealing surface 2302 to generate negative pressure adsorption force through the first and second connecting holes. Under this negative pressure, the softened tube opening material is tightly adsorbed onto the inner surface of the sealing mold cavity 23. During this process, the negative pressure is evenly applied to all areas of the tube opening material through a preset connecting path, forcing the material to completely conform to the geometry of the first sealing surface 2301 and the second sealing surface 2302, effectively suppressing local gaps or deformations caused by uneven material flow. This negative pressure-assisted mechanism works in tandem with the mechanical clamping action, maintaining close contact between the material and the mold cavity during the critical stage of material cooling and shaping, thereby ensuring the integrity and consistency of the sealed shape and improving the overall quality and aesthetics of the product.

[0056] In a preferred embodiment, the vacuum-assisted forming assembly uses an oil-free rotary vane vacuum pump as the negative pressure source, which is connected to the cavity 28 inside the clamping block 22 via a flexible connecting tube. The inner wall of the cavity 28 is coated with a polytetrafluoroethylene anti-stick coating, and multiple connecting holes are radially distributed on the surface of the first sealing surface 2301 and the corner transition area of ​​the second sealing surface 2302 to ensure that the negative pressure uniformly covers the entire surface area of ​​the sealing mold cavity 23. During the sealing operation, after the clamping block 22 is closed to the predetermined position, the vacuum pump is started and maintains the negative pressure state until the tube opening material is cooled and shaped. At this time, the tube opening material accurately replicates the surface contour of the sealing mold cavity 23 under the negative pressure adsorption.

[0057] In some of the embodiments described above in this application, a control unit is proposed to coordinate the operation of each workstation. However, in its implementation, the control unit lacks real-time detection of the workstation status and a precise stopping mechanism based on positioning. This results in the equipment still performing no-load operation when the tube throwing is missing, which not only wastes energy but may also accelerate the wear of the mechanism. Furthermore, the synchronization of the conveying cycle is insufficient, making it impossible to achieve efficient parallel operation and dynamic adaptation.

[0058] Therefore, as one embodiment of the present invention, the control unit includes: The controller is used to control the operation of the liquid filling machine; The station status sensor is connected to the controller signal and is set at each processing station to detect whether the secondary tube is present at that station. The positioning sensor 29 is set on the worktable 1 via the cross slide 30 and connected to the controller signal. It is configured to trigger a signal when it senses the positioning pin 7 on the circular conveyor line, so that the circular conveyor line stops running for a preset time and controls the corresponding station status sensor to detect the secondary tube throwing station to start operation and restart the conveyor, thereby realizing the intermittent step conveying of the mold base 6 at each station.

[0059] Among them, the controller refers to the core processing unit that performs logical operations and instruction scheduling. It can be implemented using a programmable logic controller or an embedded microprocessor, with the purpose of providing central coordination capability to coordinate the actions of the circular conveyor line and each workstation; the workstation status sensor refers to the detection device used to sense the presence of materials at the workstation. It can be implemented using a through-beam photoelectric switch or a capacitive proximity switch, with the purpose of providing real-time feedback on the actual presence status of the secondary tube at the workstation; the positioning sensor 29 refers to the trigger element used to identify the position of the positioning pin 7. It can be implemented using a reflective photoelectric sensor or a Hall effect sensor, with the purpose of accurately capturing the positioning signal of the circular conveyor line; the cross slide 30 refers to the mechanical structure that provides two-dimensional position adjustment. It can be implemented using a linear guide slide driven by a ball screw, with the purpose of ensuring the precise alignment of the positioning sensor 29 and the positioning pin 7.

[0060] Specifically, after the positioning sensor 29 is adjusted to the appropriate position by the cross slide 30, in the initial state, the controller controls the operation of the circular conveyor line. When the circular conveyor line runs to the positioning pin 7 passing through its sensing area, a stop signal is triggered, causing the circular conveyor line to pause for a preset time. During this period, the station status sensor collects the information on the presence of secondary tubes at each station in real time and transmits it to the controller. Based on the detection results, the controller only sends start commands to the stations where secondary tubes are present. After the station operation is completed, the controller restarts the circular conveyor line, thus forming a closed loop of precise positioning of the mold base 6 at each station and intermittent stepping conveying. This mechanism, through the signal linkage between the positioning sensor 29 and the station status sensor, ensures that the conveying cycle strictly matches the actual processing requirements, avoiding disordered actions caused by positional deviations or material shortages.

[0061] As a specific embodiment, the solution of this application is implemented as follows: the controller adopts a Siemens S7-1200 series PLC module, the station status sensor uses an Omron E3Z series photoelectric switch, the positioning sensor 29 is configured with a Keyence FS-V31 series fiber optic sensor, and the cross slide 30 adopts a THK brand linear guide slide structure. In actual operation, the positioning sensor 29 is finely adjusted to align with the positioning pin 7 via the cross slide 30. When the positioning pin 7 is detected, the PLC controls the circular conveyor line to stop for several seconds, while simultaneously reading the signals from the status sensors of each station. Only for the station that detects the secondary tube throwing, the liquid injection mechanism 9 or the hot melt mechanism, etc., are activated. The conveying process continues only after the operation is completed.

[0062] Through the above solution, this application effectively eliminates the invalid operation when the secondary throwing tube is missing, reduces energy consumption and the risk of mechanical wear. At the same time, through the precise stop mechanism triggered by the positioning sensor 29 and the conditional interlock of the workstation status sensor, the synchronization of the circular conveyor line and the actions of each workstation is significantly improved, realizing dynamic rhythm adjustment based on the actual material status, and ensuring the high efficiency and reliability of intermittent step conveying.

[0063] like Figure 11 The control method of the liquid filling machine shown includes the following steps: Receive the trigger signal from the positioning sensor 29 and generate control information; Control information is sent to the circular conveyor line to control the circular conveyor line to stop for a preset time, while all mold holders 6 are synchronously positioned at their respective destination stations. Check the detection status of the station status sensors at each workstation to confirm whether the secondary tube has been accurately positioned. A start command is issued to the workstation where the workstation status sensor detects a secondary tube being thrown.

[0064] The core innovation of this embodiment lies in combining the real-time trigger signal of the positioning sensor 29 with the dynamic detection of the station status sensor. This achieves precise intermittent stepping of the circular conveyor line and conditional execution of station operations, fundamentally solving the problems of poor coordination and low flexibility in the control system. It avoids idle operation, reduces energy waste and mechanical wear, and simultaneously improves production efficiency and equipment flexibility. Specifically, the signal triggered by the positioning sensor 29 when it senses the positioning pin 7 ensures that the circular conveyor line stops only at a precise position, avoiding positioning errors caused by fixed time intervals and providing an accurate basis for synchronous positioning of each station. The control unit precisely controls the preset stopping time of the circular conveyor line based on the generated control information, enabling all mold seats 6 to be synchronously positioned at their respective destination stations, creating conditions for parallel operation of multiple stations. The real-time query mechanism of the station status sensor dynamically confirms the existence status of the secondary tube throwing, triggering the corresponding actuator only when the secondary tube is accurately in place, forming an effective conditional interlocking mechanism. Through the above technical solutions, the material transfer path is significantly shortened, the waiting time between workstations is eliminated, and the system's adaptability to occasional changes in the state of incoming materials is enhanced, thereby effectively improving the continuity of production cycle and the reliability of equipment operation.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A liquid filling machine, comprising a workbench (1) for supporting the installation of workstations required for liquid filling, characterized in that, Also includes: A circular conveyor line, set on a workbench (1), is configured to transfer the secondary tubes to various workstations for processing; The liquid injection mechanism (9) is configured to inject liquid into the secondary ejection tube through a filling needle; The heat fusion mechanism is configured to perform heat fusion softening treatment on the nozzle; The sealing mechanism is configured to clamp and shape the softened pipe opening; The control unit is connected in communication with the circular conveyor line and each station on the workbench (1). It is configured to control the circular conveyor line to run according to a preset rhythm, so as to transport the secondary tubes step by step to each station in sequence, and coordinate and control the corresponding stations to perform corresponding processing operations on the secondary tubes.

2. The liquid filling machine according to claim 1, characterized in that, Also includes: The cutting mechanism (10) is used to cut off the excess sealing edge of the secondary tube after it has been clamped and shaped; The unloading mechanism is used to remove the processed secondary tubes from the circular conveyor line.

3. A liquid filling machine according to claim 1, characterized in that, The circular conveyor line includes: A ring seat (2) is fixedly installed on the workbench (1), and a ring guide rail (3) is fixedly installed on the ring seat (2). Multiple transmission seats (4) are driven by chain drive to slide along the trajectory of the annular guide rail (3). Each transmission seat (4) is provided with a mold seat (6) for inserting the secondary throwing tube.

4. A liquid filling machine according to claim 3, characterized in that, The bottom of the transmission seat (4) is symmetrically mounted with first rollers (5), and the symmetrically arranged first rollers (5) roll along the guide grooves on both sides of the annular guide rail (3).

5. A liquid filling machine according to claim 3, characterized in that, The circular conveyor line also includes a positioning component, which is used to limit the position of the transmission seat (4) when the transfer stops. The positioning component includes: Multiple positioning pins (7) are rotatably installed on the side walls of multiple transmission seats (4). A pair of support columns are symmetrically installed at the bottom of each transmission seat (4). Two sets of support members (8) are symmetrically fixed on both sides of the annular seat (2) near the injection mechanism (9). A second roller (11) is rotatably provided on the support member (8). The second roller (11) is used to support the bottom of the support column. Multiple fasteners (12) are fixedly installed on the side wall of the annular seat (2). A positioning plate (13) is slidably connected to the fastener (12). The positioning plate (13) has a positioning groove (1301) that is compatible with the positioning pin (7). A first pusher (14) is fixedly installed on the side wall of the fastener (12) for pushing the positioning plate (13) to move vertically along the fastener (12).

6. A liquid filling machine according to claim 1, characterized in that, The hot-melting mechanism includes: A heating cover (15) is disposed above the conveying track of the circular conveyor line. An installation cover (16) is fixedly installed inside the heating cover (15). Heat dissipation holes are provided on both the heating cover (15) and the installation cover (16). Multiple heating tubes (17) are symmetrically installed on both sides of the inner wall of the mounting cover (16); Two fixing plates (18) are symmetrically fixed on the inner wall of the heating cover (15), and a heating space is left between the two fixing plates (18) for the secondary throwing tube port to pass through after liquid injection.

7. A liquid filling machine according to claim 1, characterized in that, The sealing mechanism includes: Mounting bracket (19) is fixedly installed on the workbench (1), and a support frame (20) is installed on the mounting bracket (19) via a lifting assembly. Two movable seats (21) are symmetrically arranged inside the mounting frame (19) via a guide assembly. A first connecting seat is installed on the side wall of the movable seat (21), and a second connecting seat is installed on the first connecting seat. Two clamping blocks (22) are respectively set on one side of the opposite face of the two second connecting seats, and multiple split-type sealing mold cavities (23) are equally spaced on the opposite sides of the two clamping blocks (22). Two second pushers (24) are symmetrically mounted on the side wall of the mounting bracket (19) and are used to drive the two movable seats (21) to move towards each other or away from each other along the guide trajectory of the guide assembly.

8. A liquid filling machine according to claim 7, characterized in that, The guiding assembly includes two guide rods (31), both of which are fixedly installed on the inner wall of the support frame (20). Each movable seat (21) has a slide (32) at both ends, and the slide (32) slides along the surface of the guide rod (31).

9. A liquid filling machine according to claim 7, characterized in that, The sealing cavity (23) includes a first sealing surface (2301) and a second sealing surface (2302) arranged sequentially.

10. A liquid filling machine according to claim 9, characterized in that, The sealing mechanism also includes a vacuum-assisted forming component, which is configured to use negative pressure to fit the nozzle material into the sealing mold cavity (23) to form a specified full shape.

11. A liquid filling machine according to claim 10, characterized in that, The vacuum-assisted forming assembly includes: Two cavities (28) are respectively opened inside the two clamping blocks (22). Each first sealing surface (2301) has multiple first connecting holes that communicate with the inside of the cavity (28). Each second sealing surface (2302) has a second connecting hole that communicates with the inside of the cavity (28) at its internal corner. Two vacuum pumps are connected to the inside of two cavities (28) through connecting pipes, respectively, for evacuating the inside of the cavities (28).

12. A liquid filling machine according to claim 5, characterized in that, The control unit includes: The controller is used to control the operation of the liquid filling machine; The station status sensor is connected to the controller signal and is set at each processing station to detect whether the secondary tube is present at that station. The positioning sensor (29) is set on the worktable (1) via the cross slide (30) and connected to the controller signal. It is configured to trigger a signal when it senses the positioning pin (7) on the circular conveyor line, so that the circular conveyor line stops running for a preset time and controls the corresponding station status sensor to detect the secondary tube throwing station to start the conveyor after it starts operating, thereby realizing the intermittent step conveying of the mold base (6) at each station.

13. A control method for a liquid filling machine, applicable to the liquid filling machine described in claim 12, characterized in that, The control method of the controller includes the following steps: Receive the trigger signal from the positioning sensor (29) and generate control information; Control information is sent to the circular conveyor line to control the circular conveyor line to stop for a preset time; Check the detection status of the station status sensors at each workstation to confirm whether the secondary tube has been accurately positioned. A start command is issued to the workstation where the workstation status sensor detects a secondary tube being thrown.

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