Large diameter ptfe gasket forming apparatus and method of production

Abstract

The present application belongs to the technical field of polytetrafluoroethylene gasket production, and specifically provides a large-diameter polytetrafluoroethylene gasket forming device and a production method. The large-diameter polytetrafluoroethylene gasket forming device comprises a pressure forming machine and a feeding assembly. The pressure forming machine comprises a forming machine body, a lower mold and a translation mechanism. The translation mechanism can drive the lower mold to translate between a pressing station and a feeding station. The feeding assembly comprises a base, a feeding mechanism, a first driving mechanism and a second driving mechanism. When in the feeding station, the first driving mechanism and the second driving mechanism drive the feeding mechanism to move in the horizontal plane, so that it can accurately cover the entire cavity area of the lower mold, realizing automatic material laying. In the discharging process, the discharge port is kept in close contact with the upper surface of the lower mold, avoiding powder leakage. The pressure forming machine and the feeding assembly work together to realize automatic feeding of the large-diameter polytetrafluoroethylene gasket raw material, solving the problems of high labor intensity and low efficiency.

Description

Technical Field

[0001] This application belongs to the field of polytetrafluoroethylene gasket molding technology, specifically a large-diameter polytetrafluoroethylene gasket molding device and production method. Background Technology

[0002] Polytetrafluoroethylene (PTFE) gaskets are plastic sealing elements. Their manufacturing process typically involves filling PTFE raw material powder into a pre-designed mold cavity, then pressing it under pressure to initially form the gasket, followed by sintering and cooling to solidify it, resulting in the PTFE gasket product. In the petroleum and chemical industries, gaskets used in critical connections such as large containers and pipe flanges may have diameters exceeding two or even three meters. Their manufacturing quality directly affects the reliability and safety of the entire sealing system.

[0003] Under current technological conditions, some automated equipment has emerged for the production of PTFE gaskets, from automatic feeding and compression molding to finished product output. However, the design of such equipment is mainly aimed at gaskets with relatively small diameters, such as products with diameters ranging from a few centimeters to over ten centimeters. When the production target changes to large-diameter gaskets with diameters of two meters or even larger, the volume and weight of the mold increase significantly, and the volume of the cavity also increases accordingly.

[0004] Due to the large size of the molds, designing and manufacturing automated feeding mechanisms capable of precisely and uniformly distributing powder materials within such large cavities faces technical bottlenecks. Issues such as the span and rigidity of the moving mechanism, as well as the control of powder delivery uniformity, are difficult to effectively address. Therefore, in the existing production of large-diameter PTFE gaskets, traditional manual feeding methods are still widely used. This manual operation typically requires operators to manually transport bagged or barrelled PTFE powder to the large mold, then manually pour the powder gradually into the mold cavity, and finally use simple tools such as scrapers to repeatedly level the powder on the wide mold surface to achieve a relatively uniform distribution. This entirely manual operation method is not only labor-intensive and inefficient, but also, due to the uncertainty of manual operation, it is difficult to ensure that the powder's packing density and thickness are completely consistent throughout the large mold cavity. This uneven filling will be directly transmitted to the subsequent pressing and sintering processes, becoming an important cause of quality defects such as different densities in different parts of the gasket, different shrinkage rates after sintering, and even internal stress concentration. Ultimately, it will affect the overall sealing performance and service life of large-diameter PTFE gaskets, and will not be able to meet the requirements of modern large-scale industrial equipment for high-reliability sealing elements. Summary of the Invention

[0005] Based on the above background technology, this application provides a large-diameter polytetrafluoroethylene gasket molding apparatus and production method to solve the technical problem that the production of large-diameter polytetrafluoroethylene gaskets in the prior art cannot achieve automatic feeding.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, a large-diameter polytetrafluoroethylene (PTFE) gasket molding apparatus is provided, comprising: A pressure molding machine includes a molding machine body, a lower die, and a translation mechanism. The molding machine body is provided with a track along a first horizontal direction. The lower die is slidably fitted onto the track. The translation mechanism drives the lower die to move along the track, thereby moving the lower die between a pressing station and a loading station. The feeding assembly includes a base, a feeding mechanism, a first driving mechanism, and a second driving mechanism. The base has a first guide rail along a first horizontal direction and a second guide rail along a second horizontal direction. The first horizontal direction is perpendicular to the second horizontal direction. The first driving mechanism is used to drive the feeding mechanism to move along the first guide rail, and the second driving mechanism is used to drive the feeding mechanism to move along the second guide rail. The bottom of the feeding mechanism has a discharge port, which is in contact with the upper surface of the lower mold where a cavity is formed.

[0007] In one possible implementation, the lower mold has a protruding forming block at its top, the forming block being annular, and the upper surface of the forming block having the cavity; a guide plate is fixed on the base, the upper surface of the guide plate being flush with the upper surface of the forming block; when the lower mold is in the loading position, the guide plate abuts against the side of the forming block; in the initial state, the bottom of the loading mechanism is in contact with the upper surface of the guide plate.

[0008] In one possible implementation, the feeding mechanism includes: The storage bin has a first discharge port at the top, and the storage bin is equipped with an arch-breaking mechanism inside. A crushing barrel is located below the storage barrel, and its upper part is connected to the first discharge port. The crushing barrel is equipped with a crushing mechanism inside, and a second discharge port is opened at the lower part. A feeding hopper is located to the side or below the crushing hopper. The upper part of the feeding hopper is connected to the second discharge port. The inside of the feeding hopper is equipped with a stirring mechanism, and the bottom of the feeding hopper has the feeding port.

[0009] In one possible implementation, the feeding assembly further includes a feeding mechanism located at the discharge position of the first discharge port, the feeding mechanism being used to transport the material inside the storage hopper to the first discharge port.

[0010] In one possible implementation, the storage hopper, the crushing hopper, and the feeding hopper are all cylindrical barrels arranged along a vertical axis, and the axes of the storage hopper, the crushing hopper, and the feeding hopper are staggered in the height direction.

[0011] In one possible implementation, the stirring mechanism includes: A transmission rod is vertically installed inside the feeding hopper, with the bottom end of the transmission rod spaced at a predetermined distance from the feeding port; Multiple stirring rods are spaced apart from the transmission rod from top to bottom. The stirring rods extend radially along the feeding hopper, and the stirring radii of the multiple stirring rods decrease from top to bottom. A stirring motor is located at the top of the feeding hopper and is connected to the transmission rod.

[0012] In one possible implementation, the feeding assembly further includes a leveling mechanism, the leveling mechanism comprising: A scraper is positioned behind the moving trajectory of the feeding mechanism, and the bottom of the scraper is designed to fit against the upper surface of the lower mold where a cavity is formed; and The lifting rod is used to drive the scraper to move vertically up and down.

[0013] In one possible implementation, the lower mold has multiple cavities, and the upper surfaces of the multiple cavities are at the same horizontal height.

[0014] In one possible implementation, the large-diameter polytetrafluoroethylene gasket forming apparatus further includes a gasket transfer assembly, the gasket transfer assembly comprising: A suction cup mechanism is located above the base and includes multiple vacuum suction cups spaced apart along the circumferential direction. A lifting mechanism, located to the side of the base, is used to drive the suction cup mechanism to move up and down; and A rotating platform is located below the elevator and is used to drive the elevator to rotate around a vertical axis.

[0015] Compared with the prior art, the beneficial effects of the large-diameter polytetrafluoroethylene gasket molding apparatus provided in this application are: The large-diameter PTFE gasket molding apparatus provided in this application includes a pressure molding machine and a feeding assembly. The pressure molding machine includes a molding machine body, a lower mold, and a translation mechanism. The translation mechanism drives the lower mold to move between the pressing station and the feeding station. The feeding assembly includes a base, a feeding mechanism, a first drive mechanism, and a second drive mechanism. When in the feeding station, the first and second drive mechanisms drive the feeding mechanism to move in a two-dimensional plane, enabling it to accurately cover the entire cavity area of ​​the lower mold, achieving automated and uniform material distribution. During the feeding process, the feeding port remains in contact with the upper surface of the lower mold, avoiding waste and dust problems caused by powder leakage. In this application, the pressure molding machine and the feeding assembly work together to achieve automatic feeding of raw materials for large-diameter PTFE gaskets, solving the problems of high labor intensity and low efficiency associated with manual handling and dumping of powder.

[0016] Secondly, this application provides a method for producing large-diameter polytetrafluoroethylene (PTFE) gaskets, using the large-diameter PTFE gasket forming apparatus described in any of the above implementations, comprising the following steps: Select the appropriate lower mold based on the PTFE gasket to be produced and install it onto the track; Operate the pressure forming machine to move the lower mold to the loading station; The first and second drive mechanisms are manipulated to move the feeding mechanism to the initial position and fill the feeding mechanism with powdered polytetrafluoroethylene raw materials. Manipulate the first drive mechanism and the second drive mechanism to move the feeding mechanism above the lower mold and along the contour path of the upper cavity of the lower mold, so that the polytetrafluoroethylene raw material is filled into the cavity of the lower mold. After filling is completed, the first and second drive mechanisms are operated to return the feeding mechanism to its initial position. The translation mechanism drives the lower mold to move along the track to the pressing station, and the molding machine body works to press the polytetrafluoroethylene raw material in the lower mold into shape.

[0017] The method for producing large-diameter polytetrafluoroethylene gaskets provided in this application is implemented using the large-diameter polytetrafluoroethylene gasket forming device described in any of the above implementation methods, and has the same technical effect as it, so it will not be described again here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1The three-dimensional model of the large-diameter polytetrafluoroethylene gasket molding apparatus provided in the embodiments of this application Figure 1 ; Figure 2 The three-dimensional model of the large-diameter polytetrafluoroethylene gasket molding apparatus provided in the embodiments of this application Figure 2 ; Figure 3 for Figure 2 Enlarged view of part A in the middle; Figure 4 A top view of the large-diameter polytetrafluoroethylene gasket molding apparatus provided in the embodiments of this application; Figure 5 This is a schematic diagram of the feeding mechanism in an embodiment of this application; Figure 6 This is an internal sectional view of the feeding mechanism in an embodiment of this application. Explanation of reference numerals in the attached figures: 10. Pressure molding machine; 11. Molding machine body; 111. Track; 12. Lower mold; 121. Molded block; 20. Feeding assembly; 21. Base; 211. First guide rail; 212. Second guide rail; 213. Guide plate; 22. Feeding mechanism; 221. Storage hopper; 222. Crushing hopper; 2221. Crushing mechanism; 223. Discharge hopper; 2231. Transmission rod; 2232. Stirring rod; 2233. Stirring motor; 23. First drive mechanism; 24. Second drive mechanism; 25. Feeding mechanism; 26. Scraping mechanism; 261. Scraper; 262. Lifting rod; 30. Gasket transfer assembly; 31. Suction cup mechanism; 32. Elevator; 33. Rotary table. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] Please refer to the following: Figures 1 to 6 The large-diameter polytetrafluoroethylene gasket forming apparatus provided in the embodiments of this application will now be described.

[0026] In one aspect, embodiments of this application provide a large-diameter polytetrafluoroethylene (PTFE) gasket molding apparatus, which is suitable for producing PTFE gaskets with a large diameter (e.g., 1.5m or more). The device specifically includes a pressure molding machine 10 and a feeding assembly 20. The pressure molding machine 10 includes a molding machine body 11, a lower mold 12, and a translation mechanism. The molding machine body 11 is provided with a track 111 along a first horizontal direction. The lower mold 12 is slidably fitted onto the track 111. The translation mechanism is used to drive the lower mold 12 to move along the track 111, so that the lower mold 12 can move between the pressing station and the feeding station. The feeding assembly 20 includes a base 21, a feeding mechanism 22, a first driving mechanism 23, and a second driving mechanism 24. The base 21 is provided with a first guide rail 211 along a first horizontal direction and a second guide rail 212 along a second horizontal direction. The first horizontal direction is perpendicular to the second horizontal direction. The first driving mechanism 23 is used to drive the feeding mechanism 22 to move along the first guide rail 211, and the second driving mechanism 24 is used to drive the feeding mechanism 22 to move along the second guide rail 212. The bottom of the feeding mechanism 22 has a discharge port, which is in contact with the upper surface of the lower mold 12 where a cavity is formed.

[0027] Compared with the prior art, the beneficial effects of the large-diameter polytetrafluoroethylene gasket molding apparatus provided in this application embodiment are: The large-diameter polytetrafluoroethylene (PTFE) gasket molding apparatus provided in this application includes a pressure molding machine 10 and a feeding assembly 20. The pressure molding machine 10 includes a molding machine body 11, a lower mold 12, and a translation mechanism. The translation mechanism can drive the lower mold 12 to move between the pressing station and the feeding station. The feeding assembly 20 includes a base 21, a feeding mechanism 22, a first drive mechanism 23, and a second drive mechanism 24. When in the feeding station, the first drive mechanism 23 and the second drive mechanism 24 drive the feeding mechanism 22 to move in a two-dimensional plane, so that it can accurately cover the entire cavity area of ​​the lower mold 12, realizing automated and uniform material spreading. During the feeding process, the feeding port remains in contact with the upper surface of the lower mold 12, which can avoid waste and dust problems caused by powder leakage.

[0028] In this embodiment, the pressure molding machine 10 and the feeding assembly 20 work together to realize the automatic feeding of raw materials for large-diameter polytetrafluoroethylene gaskets, solving the problems of high labor intensity and low efficiency of manual handling and dumping of powder.

[0029] The pressure molding machine 10 includes a molding machine body 11, a lower mold 12, and a translation mechanism. The molding machine body 11 has a frame structure, such as a four-column hydraulic press, with two parallel rails 111 fixedly installed at its lower part along a first horizontal direction (such as the X-axis). The rails 111 can be made of high-strength steel rails or linear guides. The bottom of the lower mold 12 is equipped with sliders or rollers that match the rails 111, allowing it to slide smoothly along the rails 111. The translation mechanism is used to drive the movement of the lower mold 12, and can specifically use a hydraulic cylinder, a pneumatic cylinder, or a ball screw mechanism driven by a servo motor. One end of the translation mechanism is connected to the molding machine body 11, and the other end is connected to the lower mold 12. The lower mold 12 is reciprocated between the pressing station (located directly below the press and the upper mold) and the loading station (located to the side away from the upper mold) by extension or rotation.

[0030] During pressing, the lower die 12 is located at the pressing station, and the press drives the upper die and lower die 12 to engage. The powder material is shaped into a gasket blank under pressure. When loading polytetrafluoroethylene raw materials or removing and transferring the pressed gasket, the lower die 12 is located at the loading station.

[0031] The loading assembly 20 consists of a base 21, a loading mechanism 22, a first drive mechanism 23, and a second drive mechanism 24. The base 21 is a welded steel platform, stably set in the loading station area. A first guide rail 211 is mounted on the upper surface of the base 21 along a first horizontal direction (X-axis), and a second guide rail 212 is mounted along a second horizontal direction (Y-axis) perpendicular to it. The guide rail type can be a ball linear guide or other types, as long as the motion accuracy meets the usage requirements.

[0032] Both the first drive mechanism 23 and the second drive mechanism 24 can be driven by servo motors using ball screws to move the loading mechanism 22 along the first guide rail 211 and the second guide rail 212, respectively, achieving precise positioning in the plane. By controlling the movement time, speed, and other parameters of the first drive mechanism 23 and the second drive mechanism 24 through a PLC program, the loading mechanism 22 can move precisely along the contour of the lower mold 12 cavity. PLC control is a common control method in the electromechanical field and will not be discussed in detail here.

[0033] The feeding mechanism 22 is a hopper or bin with a discharge port at the bottom. The outline of the discharge port matches the opening shape of the cavity of the lower mold 12. When the feeding mechanism 22 moves above the mold, the discharge port can fit against the upper surface of the mold. If necessary, a flexible sealing strip (such as rubber or a brush) can be installed around the discharge port to prevent powder leakage.

[0034] like Figure 1 As shown, in a specific embodiment, the feeding mechanism 22 is slidably disposed on the second guide rail 212, the second driving mechanism 24 is used to drive the feeding mechanism 22 to move along the second guide rail 212, the second guide rail 212 is slidably disposed on the first guide rail 211, and the first driving mechanism 23 is used to drive the second guide rail 212 to move along the first guide rail 211, thereby indirectly driving the feeding mechanism 22 to move along the first guide rail 211.

[0035] Please see Figure 1 , Figure 2 and Figure 3 In some possible embodiments, the top of the lower mold 12 is provided with a protruding forming block 121. The forming block 121 is annular, made of wear-resistant steel, and fixed to the mold base by bolts. The upper surface of the forming block 121 has a cavity for forming a gasket. The depth and width of the cavity are determined according to the product specifications. A guide plate 213 is fixed on the base 21. The upper surface of the guide plate 213 is flush with the upper surface of the forming block 121. When the lower mold 12 is in the loading position, the guide plate 213 abuts against the side of the forming block 121; in the initial state, the bottom of the loading mechanism 22 is in contact with the upper surface of the guide plate 213.

[0036] In the initial state, the feeding mechanism 22 stops above the guide plate 213 before starting, with its bottom discharge port fitting against the upper surface of the guide plate 213 to form a closed starting point, preventing powder leakage during standby or initial movement. During material loading, the feeding mechanism 22 moves along the contour of the cavity, forming a closed annular path, and finally returns to the standby position along the guide plate 213.

[0037] The cavity can be circular or annular, or it can be designed into other irregular shapes, such as rectangular or annular, depending on production needs.

[0038] In this embodiment, the guide plate 213 enables a smooth transition of the feeding mechanism 22 from the standby area to the working area, avoiding collisions at the feeding port or powder leakage caused by the step between the edge of the lower mold 12 and the base 21.

[0039] It should be noted that the abutment positioning between the guide plate 213 and the forming block 121 can be used in conjunction with a proximity switch or a mechanical limit switch to send a signal to the controller indicating that the lower mold 12 is in position, ensuring that the feeding action is initiated in the correct location. These sensors and their signal processing are existing technologies and will not be discussed in detail here.

[0040] The physical characteristics of polytetrafluoroethylene (PTFE) powder include high interparticle friction and strong intermolecular forces, making it prone to adhesion. When stored in silos or hoppers, the powder easily bridges, disrupting flowability and hindering stable feeding. During storage or transportation, it easily clumps upon exposure to moisture or pressure, forming hard lumps of varying sizes. If these lumps directly enter the mold cavity, they result in severely uneven filling density. During pressing, the compression ratio of these hardened areas differs from other areas, leading to localized stress concentrations or density differences in the gasket after sintering, severely impacting sealing performance and potentially causing rejects. Due to the high interparticle friction, even without clumping, relying solely on gravity for free fall makes precise control of the feeding speed difficult and prone to intermittent feeding, preventing continuous and uniform material distribution.

[0041] To achieve precise feeding of polytetrafluoroethylene powder, please refer to [link / reference needed]. Figure 3 , Figure 5 and Figure 6 In some possible embodiments, the feeding mechanism 22 includes a storage bin 221, a crushing bin 222, and a discharging bin. The storage bin 221 has a first discharge port at its upper part and an arch-breaking mechanism inside. The crushing bin 222 is located below the storage bin 221 and its upper part is connected to the first discharge port. The crushing bin 222 has a crushing mechanism 2221 inside and a second discharge port at its lower part. The discharging bin is located to the side or below the crushing bin 222. The upper part of the discharging bin is connected to the second discharge port. The discharging bin has a stirring mechanism inside and a discharging port at its bottom.

[0042] Storage hopper 221 is a large-capacity cylindrical container with an open top for storing polytetrafluoroethylene (PTFE) powder. The top opening is used for adding material. Storage hopper 221 has an internal anti-bridging mechanism, such as motor-driven stirring blades or a vibrator, to prevent the PTFE powder from forming arches that block the discharge port due to moisture or compression. A first discharge port is located on the lower side or bottom of storage hopper 221, communicating with crushing hopper 222 for conveying material to crushing hopper 222.

[0043] The crushing drum 222 is located directly below or to the side of the storage drum 221, and contains a crushing mechanism 2221, such as a pair of opposing rotating crushing rollers or a high-speed rotating blade assembly, for crushing any agglomerated powder. A second discharge port is opened at the bottom of the crushing drum 222, connecting to the feeding drum. In the production of large-diameter PTFE gaskets, only by eliminating agglomerates can the uniformity of the subsequently filled powder be ensured, thereby avoiding defects caused by localized density differences during the pressing and sintering stages. This uniformity is particularly important for large-diameter gaskets.

[0044] The feeding hopper is located to the side or below the crushing hopper 222 (depending on the space layout). It contains a stirring mechanism consisting of motor-driven stirring blades, which slowly and continuously agitates the powder, keeping it in a dynamically loose state. This greatly improves its flowability, allowing it to flow smoothly like a fluid and be discharged. A feeding port is located at the bottom of the feeding hopper, which serves as the final outlet for feeding material into the mold cavity.

[0045] In this embodiment, the storage bucket 221, the crushing bucket 222 and the feeding bucket form a multi-layer layout from top to bottom. The multi-layer layout structure realizes the pretreatment of polytetrafluoroethylene powder, ensuring that the polytetrafluoroethylene powder is loosely and evenly filled into the cavity.

[0046] Specifically, the anti-bridging mechanism prevents powder blockage in the storage hopper 221, ensuring continuous material supply; the crushing mechanism 2221 eliminates agglomerates, preventing hard lumps from entering the mold cavity and affecting the pressing quality; and the mixing mechanism further homogenizes the powder, ensuring uniform material density. This series of processes results in loose and consistent powder filling the mold cavity, laying the foundation for subsequent pressing of high-quality gaskets with uniform density and thickness.

[0047] Please see Figure 5 The feeding assembly 20 also includes a feeding mechanism 25, which is located at the discharge position of the first discharge port. The feeding mechanism 25 is used to transport the material inside the storage hopper 221 to the first discharge port. The feeding mechanism 25 can be a screw conveyor, a star-shaped distributor, etc., to ensure that there is always sufficient material in the crushing hopper 222.

[0048] Please see Figure 5 and Figure 6 The storage hopper 221, crushing hopper 222, and discharging hopper are all cylindrical barrels arranged along a vertical axis, and their axes are staggered in the height direction. This staggered design avoids the impact and compaction caused by the vertical free fall of powder, reduces the risk of blockage, and facilitates independent inspection and maintenance of each hopper.

[0049] Please see Figure 6The stirring mechanism includes a transmission rod 2231 and multiple stirring rods 2232. The transmission rod 2231 is vertically installed inside the feeding hopper, with its bottom end spaced a preset distance from the feeding port. Multiple stirring rods 2232 are spaced apart from the transmission rod 2231 from top to bottom. The stirring motor 2233 is located at the top of the feeding hopper and connected to the transmission rod 2231. It is used to slowly stir the material in the feeding hopper, making the material flow and easier to settle downwards near the feeding port.

[0050] To avoid uneven material distribution near the discharge port at the bottom of the feeding hopper, the stirring rod 2232 extends radially along the feeding hopper, and the stirring radius of the multiple stirring rods 2232 distributed from top to bottom decreases. This minimizes the disturbance to the material at the bottom, ensuring material flowability while preventing excessive stirring that could cause the powder near the discharge port to be compacted or form eddies, thus ensuring smooth and stable discharge.

[0051] Please see Figure 3 and Figure 4 In some possible embodiments, the feeding assembly 20 further includes a leveling mechanism 26, which includes a scraper 261 and a lifting rod 262. The scraper 261 is located behind the moving path of the feeding mechanism 22, and its bottom is used to fit against the upper surface of the lower mold 12 where the cavity is formed. The lifting rod 262 is used to drive the scraper 261 to move vertically up and down. When the feeding mechanism 22 moves along the set path and feeds the powder, the scraper 261 at the rear levels the powder that has just been filled into the cavity, making its filling height uniform. The scraper 261 can be long and narrow or curved, and its number can be set to one or more as needed.

[0052] To produce multiple gaskets simultaneously, the lower mold 12 has multiple cavities, with the upper surfaces of the cavities at the same horizontal level. When the diameters of the gasket cavities are different, the multiple cavities are concentrically arranged from the inside out, and the diameters of the cavities increase from the inside out, thus allowing multiple gaskets of different diameters to be processed simultaneously.

[0053] Please see Figure 1 , Figure 2 and Figure 4 In some possible embodiments, the large-diameter polytetrafluoroethylene gasket forming apparatus further includes a gasket transfer assembly 30, which includes a suction cup mechanism 31, a lift 32, and a rotary table 33.

[0054] The suction cup mechanism 31 is located above the base 21 and includes multiple vacuum suction cups spaced apart along the circumference; the lifting mechanism 32 is located on the side of the base 21 and is used to drive the suction cup mechanism 31 to lift; the rotating platform 33 is located below the lifting mechanism 32 and is used to drive the lifting mechanism 32 to rotate around the vertical axis.

[0055] Multiple vacuum suction cups are provided, enabling simultaneous adsorption of different positions on the gasket, ensuring uniform force distribution across the entire gasket. The lifting platform 32 drives the suction cup mechanism 31 to move up and down, changing the height of the vacuum suction cups for easier material handling. The rotary table 33 drives the suction cup mechanism 31 between the gasket picking position (i.e., the loading position) and the unloading position, completing the gasket unloading and transfer. The suction cup mechanism 31, the lifting platform 32, and the rotary table 33 work together to achieve non-contact handling of large-diameter PTFE gasket blanks.

[0056] As the suction cup mechanism 31 rotates with the elevator 32, it moves between the material picking position and the material discharging position. The material picking position is located above the lower mold 12, and the material discharging position is located above the polytetrafluoroethylene gasket storage area.

[0057] The vacuum suction cup is mounted on a fixed frame, which has multiple adjustment holes distributed in a ring. The long axis of the adjustment holes is parallel to the radius of the ring distribution trajectory of the vacuum suction cup. The vacuum suction cup is located at the corresponding adjustment hole and can move along the long axis of the adjustment hole.

[0058] The adjustment holes are either oblong or elongated, with their long axes pointing towards the center of the annular distribution (i.e., the radial direction). Each vacuum suction cup is installed in one adjustment hole, and its position can be adjusted along the long axis of the adjustment hole to change the suction diameter and accommodate different gasket diameters.

[0059] In this embodiment, the gasket transfer assembly 30 replaces the manual lifting and transfer in the prior art, which saves more manpower and is less likely to cause bending or damage to the gasket.

[0060] Secondly, embodiments of this application provide a method for producing large-diameter polytetrafluoroethylene (PTFE) gaskets, employing the large-diameter PTFE gasket forming apparatus of any of the above embodiments, including the following steps: Based on the diameter, thickness, and other parameters of the PTFE gasket to be produced, select the corresponding lower mold 12 and install it on the track 111, and connect it to the drive end of the translation mechanism to ensure that the lower mold 12 can move smoothly between the pressing station and the loading station.

[0061] The pressure molding machine 10 is operated to move the lower mold 12 to the loading station; when the lower mold 12 moves to the designated position, its side abuts against the guide plate 213 on the base 21 to achieve precise positioning, while the upper surface of the molding block 121 on the lower mold 12 remains flush with the upper surface of the guide plate 213.

[0062] The first drive mechanism 23 and the second drive mechanism 24 are operated to move the feeding mechanism 22 to the initial position, and the powdered polytetrafluoroethylene raw material is loaded into the feeding mechanism 22. The specific loading process is as follows: the polytetrafluoroethylene powder is added to the storage tank 221, the anti-bridging mechanism is activated to prevent the powder from bridging, the powder enters the crushing tank 222 through the first discharge port, the crushing mechanism 2221 breaks up any possible lumps, and then the powder enters the discharge tank. The stirring mechanism continuously stirs to maintain the fluidity of the powder. Finally, the powder fills the discharge tank and waits for the discharge command.

[0063] The first drive mechanism 23 and the second drive mechanism 24 are operated to move the feeding mechanism 22 above the lower mold 12 and along the contour path of the upper cavity of the lower mold 12, so that the polytetrafluoroethylene raw material is filled into the cavity of the lower mold 12. During the movement, the feeding port at the bottom of the feeding barrel continuously fills the cavity with polytetrafluoroethylene powder, and the filling amount is controlled by the moving speed and the opening of the feeding port. At the same time, the scraping mechanism 26 located in front of the moving trajectory of the feeding mechanism 22 is lowered by the lifting rod 262, so that the bottom of the scraper 261 is in contact with the upper surface of the molding block 121, and the powder filled into the cavity is scraped flat during the filling process to ensure that the powder has a consistent thickness and uniform distribution throughout the cavity area.

[0064] After filling is completed, the first drive mechanism 23 and the second drive mechanism 24 are operated to make the feeding mechanism 22 return to the initial position. The translation mechanism drives the lower mold 12 to move along the track 111 to the pressing station. The molding machine body 11 works to press the polytetrafluoroethylene raw material in the lower mold 12 into shape, and obtains the preliminary shaped polytetrafluoroethylene gasket blank.

[0065] If the lower mold 12 has multiple cavities, then in the filling step, the feeding mechanism 22 will cover all cavity areas in sequence, completing the filling and smoothing of multiple gaskets at one time, greatly improving production efficiency.

[0066] After pressing, the upper mold is reset, and the lower mold 12 can be moved to the loading station again; the gasket transfer assembly 30 is activated, and the lifting platform 32 drives the suction cup mechanism 31 to descend, so that the vacuum suction cup contacts the surface of the gasket blank, and the vacuum system is activated to adsorb the gasket; after the adsorption is firm, the lifting platform 32 drives the suction cup mechanism 31 to rise and remove the gasket from the mold cavity; then the rotary table 33 drives the lifting platform 32 and the suction cup mechanism 31 to rotate around the vertical axis, transferring the gasket to the top of the storage area, the vacuum is released, the gasket is lowered, and the automatic transfer is completed.

[0067] It should be noted that after pressing is completed, the gasket blank can be removed from the lower mold 12 by the suction cup mechanism 31 on the gasket transfer assembly 30. Alternatively, an ejector mechanism can be provided below the lower mold 12. The ejector mechanism is a hydraulic rod or a similar structure that can eject the gasket blank. After the gasket is ejected, it is transferred by the suction cup mechanism 31 on the gasket transfer assembly 30.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A large-diameter polytetrafluoroethylene gasket forming apparatus for producing a polytetrafluoroethylene gasket having a diameter of 1.5 m or more, characterized by, include: A pressure molding machine (10) includes a molding machine body (11), a lower die (12), and a translation mechanism. The molding machine body (11) is provided with a track (111) along a first horizontal direction. The lower die (12) is slidably fitted onto the track (111). The translation mechanism is used to drive the lower die (12) to move along the track (111), so that the lower die (12) moves between a pressing station and a loading station. The feeding assembly (20) includes a base (21), a feeding mechanism (22), a first driving mechanism (23), and a second driving mechanism (24). The base (21) is provided with a first guide rail (211) along a first horizontal direction and a second guide rail (212) along a second horizontal direction. The first horizontal direction is perpendicular to the second horizontal direction. The first driving mechanism (23) is used to drive the feeding mechanism (22) to move along the first guide rail (211), and the second driving mechanism (24) is used to drive the feeding mechanism (22) to move along the second guide rail (212). The bottom of the feeding mechanism (22) has a discharge port, which is in contact with the upper surface of the lower mold (12) where a cavity is formed. The feeding mechanism (22) includes: The storage hopper (221) has a first discharge port at the top, and the storage hopper (221) is equipped with an arch-breaking mechanism inside; A crushing barrel (222) is located below the storage barrel (221), and its upper part is connected to the first discharge port. The crushing barrel (222) contains a crushing mechanism (2221), and its lower part has a second discharge port. A feeding hopper (223) is located on the side or below the crushing hopper (222). The upper part of the feeding hopper (223) is connected to the second discharge port. The feeding hopper (223) is equipped with a stirring mechanism inside. The feeding port is opened at the bottom of the feeding hopper. The storage hopper (221), the crushing hopper (222), and the feeding hopper (223) are all cylindrical hoppers arranged along the vertical axis, and the axes of the storage hopper (221), the crushing hopper (222), and the feeding hopper (223) are staggered in the height direction; The stirring mechanism includes: The transmission rod (2231) is vertically installed inside the feeding hopper (223), and the bottom end of the transmission rod (2231) is spaced at a preset distance from the feeding port; Multiple stirring rods (2232) are spaced apart from the transmission rod (2231) from top to bottom. The stirring rods (2232) extend radially along the feeding hopper (223), and the stirring radii of the multiple stirring rods (2232) distributed from top to bottom decrease. A stirring motor (2233) is located on the top of the feeding hopper (223) and connected to the transmission rod (2231); The large-diameter polytetrafluoroethylene gasket forming apparatus further includes a gasket transfer assembly (30), which includes: A suction cup mechanism (31) is located above the base (21) and includes a plurality of vacuum suction cups spaced apart along the circumferential direction. The vacuum suction cups are mounted on a fixed frame, and the fixed frame has a plurality of adjustment holes. The plurality of adjustment holes are distributed in a ring, and the long axis of the adjustment holes is parallel to the radial direction of the ring distribution trajectory of the plurality of vacuum suction cups. The vacuum suction cups are located at the corresponding adjustment holes and can move along the long axis of the adjustment holes. A lifting mechanism (32), located on the side of the base (21), is used to drive the suction cup mechanism (31) to lift; and A rotating platform (33) is located below the elevator (32) and is used to drive the elevator (32) to rotate around a vertical axis. The lower mold (12) has a protruding forming block (121) on its top. The forming block (121) is annular and has a cavity on its upper surface. A guide plate (213) is fixed on the base (21). The upper surface of the guide plate (213) is flush with the upper surface of the forming block (121). When the lower mold (12) is in the loading position, the guide plate (213) abuts against the side of the forming block (121). In the initial state, the bottom of the loading mechanism (22) is in contact with the upper surface of the guide plate (213).

2. The large diameter polytetrafluoroethylene gasket forming apparatus of claim 1 wherein, The feeding assembly (20) also includes a feeding mechanism (25), which is located at the discharge position of the first discharge port. The feeding mechanism (25) is used to transport the material inside the storage tank (221) to the first discharge port.

3. The large-diameter polytetrafluoroethylene gasket forming apparatus according to claim 1, characterized in that, The feeding assembly (20) further includes a leveling mechanism (26), which includes: A scraper (261) is located behind the moving trajectory of the feeding mechanism (22), and the bottom of the scraper (261) is used to fit against the upper surface of the lower mold (12) where the cavity is formed; and The lifting rod (262) is used to drive the scraper (261) to rise and fall vertically.

4. The large-diameter polytetrafluoroethylene gasket forming apparatus according to claim 1, characterized in that, The lower mold (12) has multiple cavities, and the upper surfaces of the multiple cavities are at the same horizontal height.

5. A method for producing large-diameter polytetrafluoroethylene gaskets, characterized in that, The large-diameter polytetrafluoroethylene gasket molding apparatus according to any one of claims 1 to 4 includes the following steps: According to the polytetrafluoroethylene gasket to be produced, select the corresponding lower mold (12) and install it on the track (111); Operate the pressure molding machine (10) to move the lower mold (12) to the loading station; Manipulate the first drive mechanism (23) and the second drive mechanism (24) to move the feeding mechanism (22) to the initial position and fill the feeding mechanism (22) with powdered polytetrafluoroethylene raw materials; Manipulate the first drive mechanism (23) and the second drive mechanism (24) to move the feeding mechanism (22) above the lower mold (12) and move along the contour path of the upper cavity of the lower mold (12) so that the polytetrafluoroethylene raw material is filled into the cavity of the lower mold (12); After filling is completed, the first drive mechanism (23) and the second drive mechanism (24) are operated to make the feeding mechanism (22) return to the initial position. The translation mechanism drives the lower mold (12) to move along the track (111) to the pressing station. The molding machine body (11) works to press the polytetrafluoroethylene raw material in the lower mold (12) into shape.

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