Multi-station vacuum pressure integrated hot-pressing equipment for quartz products

Abstract

The application discloses a multi-station vacuum pressure integrated hot-pressing equipment for quartz products, which comprises a furnace body, a vacuum system, a supporting material table, a heater, a plurality of mechanical hot-pressing devices and a control system, wherein the vacuum system is communicated with the furnace body; a lower cover is arranged at the bottom of the furnace body, a lifting device and a translation mechanism are connected below the lower cover, and the supporting material table is fixedly installed on the lower cover; the plurality of mechanical hot-pressing devices are arranged on the top of the furnace body and correspond to quartz product preforms on the supporting material table one by one, the mechanical hot-pressing devices pass through the top of the furnace body and are installed on independent supporting frames which are separated from the structure of the furnace body; a multi-stage combined dynamic sealing device is arranged between a pressing rod and the furnace body; a heat preservation and insulation device for blocking heat conduction is arranged below the dynamic sealing device; and a sealed isolation chamber for reducing the contamination degree of the heater is arranged between the heater and the quartz product. The application realizes multi-station differentiated high-temperature hot-pressing through an independent control system, and solves the process synchronization problem of processing multiple specifications of quartz products in the same furnace.

Description

Technical Field

[0001] This invention belongs to the field of hot pressing technology for quartz products, specifically relating to a multi-station integrated vacuum pressure hot pressing device for quartz products. Background Technology

[0002] High-purity quartz products (such as silicon wafers for semiconductors, quartz crucibles for photovoltaics, optical fiber preforms, and optical quartz products) are often processed from high-purity quartz ingots. Various shapes of high-purity quartz ingots are formed by melting quartz at high temperatures and then flattening it by its own weight. High-temperature melting and reshaping is a crucial process in quartz processing. High-quality quartz ingots require high-temperature melting and reshaping under vacuum or a protective atmosphere. This process also eliminates internal air bubbles and closed gaps, primarily to obtain the desired shape. Traditional equipment is mostly a single-station structure without a hot mechanical pressure device, resulting in low efficiency and high energy consumption. Furthermore, it can only flatten and fill the mold by its own weight in a high-temperature molten state. The molds are often regular vertical cylinders, triangles, or squares with vertical sidewalls. If the quartz ingot product requires a specific shape, such as a drum-shaped (thick in the middle, thin at both ends) or a narrow-waisted (thin in the middle, thick at both ends) product, simply flattening it by its own weight is insufficient to achieve the desired effect, and the quality of the curved side sections of the product is difficult to guarantee. It cannot adapt to problems such as processing products of multiple specifications in the same furnace.

[0003] Existing technologies include several multi-station hot pressing devices, such as the multi-station compact high-vacuum high-pressure hot pressing device disclosed in CN210851416U. This patent discloses a multi-station hot pressing device comprising a hot pressing chamber, multiple hot pressing levers, a material tray track, and a vacuum system. The hot pressing levers are symmetrically arranged along the center line of the hot pressing chamber, enabling simultaneous hot pressing of multiple products and effectively improving work efficiency. However, this equipment is mainly suitable for hot pressing of conventional materials. When applied to the special processing of quartz products at high temperatures, it faces the following technical challenges: First, the air leakage problem caused by multiple stations is more prominent at high temperatures, and ordinary sealing structures cannot withstand the dual challenges of high-temperature heat radiation and the reciprocating motion of the pressure rods; second, heat leakage at the perforations of the pressure rods leads to a large loss of heat, affecting the stability of the thermal field and energy efficiency; third, in a multi-station layout, the pressure head occupies top space, and traditional heater arrangement methods cannot guarantee temperature uniformity within a large-size furnace; fourth, inconsistent melting rates of products at different stations lead to process control challenges. Existing technologies have not yet provided effective solutions to the above problems. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of existing technologies and provide a multi-station vacuum pressure integrated hot pressing equipment for quartz products that can process multiple quartz products simultaneously, adapt to the process differences of products with different specifications, and ensure processing quality under high temperature and high pressure conditions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a multi-station integrated vacuum pressure hot pressing device for quartz products, comprising: The furnace body has an insulation layer fixedly installed on its inner side wall to reduce heat loss from the furnace body. The vacuum system, connected to the furnace body, is used to evacuate the inner cavity of the furnace, providing the necessary vacuum environment for the processing of quartz product preforms. The support platform, located inside the furnace body, is used to simultaneously support multiple quartz product preforms; The heater is located inside the furnace body and is arranged around the quartz product preform on the support platform to provide the heat required for melting the quartz product. Multiple mechanical hot pressing devices are installed on the top of the furnace body, and each of the multiple mechanical hot pressing devices is set in a corresponding manner to the quartz product preforms on the support platform, for hot pressing treatment of the quartz product preforms. The control system is independently connected to multiple mechanical hot pressing devices. It is used to independently control the pressure, displacement and timing of the corresponding mechanical hot pressing devices according to the real-time melting state of each quartz product preform on the support platform. The real-time melting state refers to the melting state characterized by the change in the deformation height of the quartz product preform as monitored in real time.

[0006] Preferably, the mechanical hot pressing device includes a drive assembly, a pressure rod, and a high-strength, high-temperature resistant pressure head. The lower end of the pressure rod passes through the top of the furnace body and is connected to the high-strength, high-temperature resistant pressure head at that end. The upper end of the pressure rod is connected to the drive assembly, and the drive assembly is connected to the control system. The control system controls the drive assembly to realize the action of the pressure rod.

[0007] The drive assembly can be hydraulically driven, pneumatically driven, or electrically driven, with hydraulic drive being preferred to obtain stable pressure output. The high-strength, high-temperature resistant pressure head adopts a combination structure of graphite or CFC material and heat-resistant stainless steel. The part of the pressure rod located inside the furnace body insulation layer is made of graphite or CFC material, which has excellent high-temperature strength, low coefficient of thermal expansion, and good thermal shock resistance, and can maintain sufficient mechanical strength in a high-temperature environment of 2100℃. The part of the pressure rod located outside the insulation layer adopts a combination structure of heat-resistant stainless steel and graphite / CFC material. The part of the pressure rod made of graphite / CFC material penetrates the upper insulation layer, and the part of heat-resistant stainless steel penetrates the furnace body cover through a sealing mechanism. This part does not directly bear the high temperature, but is only used to transmit pressure and facilitate sealing. However, a cooling water circulation structure is set inside the pressure rod to remove the heat conducted by the pressure rod and prevent excessive heat from damaging the sealing ring. The two parts of the pressure rod are fixed by threaded connection or flange connection to form a combined pressure rod structure, which facilitates subsequent maintenance and replacement.

[0008] Preferably, it also includes a support frame that is separate from and independently set up from the furnace body. The lower end of the support frame is fixed to the ground or equipment foundation, and the upper end of the support frame is provided with an installation platform. The drive components of multiple mechanical hot pressing devices are fixedly installed on the installation platform. A through hole is opened on the top of the furnace body corresponding to the position of each mechanical hot pressing device for the pressure rod to pass through. A dynamic sealing device is provided between the pressure rod and the through hole.

[0009] The support frame, which is independently set on the outside of the furnace body, prevents the mechanical pressure generated by the mechanical hot pressing device from being transmitted to the furnace body. This effectively prevents the furnace body from deforming or being damaged due to long-term exposure to high pressure, while also ensuring the alignment accuracy between the high-strength, high-temperature resistant pressure head and the support platform.

[0010] Preferably, a dynamic sealing device is provided between the mechanical hot pressing device and the top of the furnace body. The dynamic sealing device includes a pressing mechanism and multiple sets of sealing rings. The pressing mechanism is located on the upper side of the multiple sets of sealing rings to prevent the sealing rings from falling off and deforming. A separation ring is provided between the pressing mechanism and its adjacent sealing rings, as well as between two adjacent sealing rings. The sealing rings include multiple sets of O-ring rubber sealing rings and multiple sets of lip sealing rings with skeletons distributed from top to bottom.

[0011] Based on this dynamic sealing device, the vacuum environment inside the furnace is maintained during the reciprocating motion of the pressure rod. The partition ring is used to maintain the axial spacing and positioning accuracy of each sealing ring. The O-ring rubber seal is located above, providing radial elastic preload to compensate for the diameter change of the pressure rod caused by thermal expansion. The skeletonized lip seal is located below, with a built-in metal skeleton. The metal skeleton is used to improve the overall strength of the seal and prevent twisting deformation caused by friction / thrust during installation and operation. The lip faces the inside of the furnace. Under the negative pressure inside the furnace, the lip fits tightly with the surface of the pressure rod to form a dynamic sealing line. The surface roughness of the pressure rod and the sealing ring is ≤Ra0.8, which can effectively reduce the leakage channels formed by micro-unevennesses and make the gap of the sealing pair smaller than the mean free path of gas molecules, forming a molecular sealing effect.

[0012] Preferably, it also includes a thermal insulation device located below the dynamic sealing device. The thermal insulation device includes an upper hard felt board, a lower hard felt board, a soft felt layer, a first thermal insulation hard felt cylinder, a second thermal insulation hard felt cylinder, and a support plate. The support plate is sleeved on the pressure rod. The lower hard felt board, the second thermal insulation hard felt cylinder, the upper hard felt board, and the first thermal insulation hard felt cylinder are arranged sequentially from bottom to top on the upper part of the support plate and sleeved on the pressure rod. The soft felt layer is arranged between the upper hard felt board and the lower hard felt board and is located outside the second thermal insulation hard felt cylinder. The first thermal insulation hard felt cylinder is T-shaped to cover the exposed part of the pressure rod and block axial heat conduction.

[0013] The device comprises a support plate serving as the foundation for the thermal insulation system; a soft felt layer made of low-density carbon fiber felt containing numerous static air pockets and exhibiting extremely low thermal conductivity; a first thermal insulation hard felt cylinder with a T-shaped structure, its vertical portion extending to the exposed area of ​​the pressure rod, and its horizontal portion covering the upper surface of the hard felt plate to block the radial radiation of heat conducted from the pressure rod to the outside of the insulation layer; and a second thermal insulation hard felt cylinder tightly fitted to the pressure rod, forming an axial thermal barrier to prevent heat transfer along the axial gap to the outside of the insulation layer. This thermal insulation system, through multi-stage thermal resistance series connection, effectively reduces heat leakage at the pressure rod perforations.

[0014] Preferably, it also includes a sealed isolation chamber located inside the furnace body and made of carbon material. The sealed isolation chamber is disposed between the heater and multiple quartz product preforms to reduce the contamination of the heater by-products generated during the processing of the quartz product preforms.

[0015] The sealed isolation chamber has a cylindrical structure and is fitted around multiple quartz product preforms. Its lower end is sealed to the support platform, and its upper end is sealed to the inner side of the top of the furnace body. This separates the heater from the multiple quartz product preforms on the inner and outer sides of the sealed isolation chamber, thereby reducing the contamination of the heater by byproducts (such as volatiles and oxide dust) generated during the processing of the quartz product preforms and extending the service life of the heater.

[0016] Preferably, the heater includes a first heater arranged along the circumferential direction of the outer side of the sealed isolation chamber and a second heater located at the top of the inner side of the furnace body in a serpentine or spiral shape.

[0017] The first heater consists of multiple heating elements evenly distributed along the outer circumference of the sealed isolation chamber to form an annular heating zone, providing basic heating power. The second heater is located on the top inner side of the furnace body, distributed in a serpentine or spiral shape. The second heater has clearance gaps set according to the distribution positions of multiple mechanical hot pressing devices. The positions of the clearance gaps correspond to the positions of the high-strength, high-temperature resistant pressure heads to avoid interference between the second heater and the pressure heads. It should be noted that the heating power density of the second heater at the clearance gaps is greater than that in the non-clearance areas, which is used to compensate for the heat loss caused by the pressure heads blocking the clearance areas and ensure the uniformity of the internal temperature of the furnace body.

[0018] Preferably, it also includes a pressure detection unit and a displacement detection unit respectively connected to the control system. The pressure detection unit is used to monitor the pressure changes of each mechanical hot pressing device in real time, and the displacement detection unit is used to monitor the changes in the deformation height of the quartz product preform in real time.

[0019] The pressure detection unit includes a pressure sensor installed on each mechanical hot pressing device to monitor the pressure value applied by each mechanical hot pressing device to the corresponding quartz product preform in real time; the displacement detection unit includes a displacement sensor installed on each mechanical hot pressing device to monitor the displacement of the corresponding high-strength, high-temperature resistant pressure head in real time, thereby obtaining the change in the deformation height of the quartz product preform.

[0020] Preferably, the bottom of the furnace body is provided with a lower cover for sealing the lower side of the furnace body. A lifting device and a translating trolley are connected below the lower cover. A supporting material platform is fixedly installed on the lower cover. The output end of the lifting device is connected to the bottom of the lower cover and is used to drive the lower cover to rise and fall in the vertical direction to realize the opening and sealing of the bottom of the furnace body. The translating trolley is located below the lifting device. The base of the lifting device is fixedly installed on the translating trolley. The bottom of the translating trolley is provided with traveling wheels and a traveling drive mechanism to drive the translating trolley to move along a horizontal track, thereby realizing the horizontal transfer of the lower cover and the supporting material platform.

[0021] The lifting device includes a lifting drive mechanism and a guiding mechanism. The output end of the lifting drive mechanism is connected to the bottom of the lower cover and is used to drive the lower cover to rise and fall vertically to open and seal the bottom of the furnace body. The lifting drive mechanism can be a hydraulic cylinder, a pneumatic cylinder, or an electric screw mechanism. The guiding mechanism is used to guide the lifting process of the lifting drive mechanism. It can be a linear guide rail or a guide column and guide sleeve structure to ensure that the lower cover is lifted and lowered smoothly and accurately. The traveling drive mechanism can be driven by a motor reducer to drive the translation trolley to move along the horizontal track, thereby realizing the horizontal transfer of the lower cover and the supporting material platform. When the lifting device lowers the lower cover to the low position, the translation trolley can drive the lower cover and the supporting material platform to move horizontally out of the area below the furnace body, thereby realizing the loading and unloading operation of materials.

[0022] Preferably, the vacuum system includes a secondary pump set and a diffusion pump connected in series or in parallel with the secondary pump set, wherein the secondary pump set includes a mechanical pump and a Roots pump connected in series, an exhaust port is provided on the side of the furnace body, the exhaust port is connected to the vacuum system through an exhaust pipe, and a vacuum valve is provided on the exhaust pipe.

[0023] Among them, the mechanical pump serves as the backing pump, used to evacuate the pressure inside the furnace from atmospheric pressure to a low vacuum state (e.g., 1000 Pa); the Roots pump serves as the booster pump, used to increase the pumping speed and further reduce the pressure to below 1 Pa; the diffusion pump serves as the main pump, featuring high pumping speed and high ultimate vacuum, capable of evacuating the furnace pressure to 10 Pa. -4 Below Pa, it meets the strict vacuum requirements for high-temperature processing of quartz products. Since the secondary pump set is connected in series or parallel with the diffusion pump, the series and parallel connection mode of the secondary pump set and the diffusion pump can be switched at any time using the built-in program of the control system.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects: (1) By setting up multiple independently controlled mechanical hot pressing devices, the independent control system can apply pressure according to the real-time melting state of the quartz products at each station. The independent support frame and the independent control system work together to ensure the long-term alignment accuracy between the press head and the support platform when processing multiple specifications of products in the same furnace, and to realize differentiated process control at each station, thereby increasing the pass rate of multiple specifications of products in the same furnace to more than 96%.

[0025] (2) By independently supporting multiple mechanical hot pressing devices on a support frame installed on the ground or equipment foundation, the independent support frame prevents the furnace body from being subjected to mechanical pressure, which can reduce the structural strength requirements of the furnace body to a certain extent and is beneficial to the structural accuracy and service life of the furnace body during long-term operation. Moreover, based on the bottom discharge structure combining the bottom cover, lifting device and translating car, the number of times the top device moves in the non-working state is greatly reduced, ensuring the long-term operational stability of the device.

[0026] (3) The present invention adopts a circumferential ring uniform heating and top compensation heating structure, and combines the top irregular heater to set an avoidance gap to compensate for the heating power density for the pressure head distribution. It can achieve a temperature uniformity of ±7.5℃ in the inner cavity of the furnace with a diameter of φ3000mm or more, and provides temperature guarantee for the quality qualification rate of quartz products.

[0027] (4) In this invention, the heat insulation device is placed below the dynamic sealing device. On the one hand, the heat conducted by the pressure rod is blocked inside the furnace body through the multi-stage thermal resistance series structure, so that the working temperature at the dynamic sealing device is significantly lower than the furnace temperature. On the other hand, the lower ambient temperature slows down the thermal aging rate of the sealing ring and extends the sealing life. At the same time, the good sealing performance prevents heat loss through convection, further enhancing the heat insulation effect. The two form a positive feedback synergistic mechanism of "sealing protection and heat insulation - heat insulation and enhanced sealing". Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a multi-station vacuum pressure integrated hot pressing device for quartz products according to the present invention; Figure 2 This is a cross-sectional view of the dynamic sealing device in this invention; Figure 3This is a cross-sectional view of the thermal insulation device in this invention; Figure 4 This is a schematic diagram of the heater arrangement in this invention; Figure 5 This is a schematic diagram of the arrangement of the second heater at the top of the furnace body in the three-station configuration of this invention.

[0030] In the diagram: 1. Furnace body, 2. Vacuum system, 31. First heater, 32. Second heater, 4. Support platform, 51. Drive assembly, 52. Pressure rod, 53. High-strength, high-temperature resistant pressure head, 6. Support frame, 61. Mounting platform, 71. Clamping mechanism, 72. O-ring seal, 73. Lip seal, 74. Separator ring, 81. Upper hard felt plate, 82. Lower hard felt plate, 83. Soft felt layer, 84. First heat-insulating hard felt cylinder, 85. Second heat-insulating hard felt cylinder, 86. Support plate, 9. Sealed isolation chamber, 10. Lower cover, 11. Lifting device, 12. Horizontal transfer vehicle. Detailed Implementation

[0031] To make the objectives, technical solutions, and technical effects of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings, multiple embodiments, and comparative examples. In the following description, the same components are referred to by the same reference numerals.

[0032] The following is combined with Figures 1-5 Explain the cooperative relationship between the various components of this invention during the complete working cycle: During the loading and sealing stage: the lifting device 11 drives the lower cover 10 to descend, and the translation cart 12 moves the support platform 4 out of the furnace body 1. The operator places multiple quartz product preforms (which can be of the same or different specifications) on the support platform 4. The translation cart 12 is reset, and the lifting device 11 drives the lower cover 10 to rise and seal with the bottom of the furnace body 1. At this time, each quartz product preform on the support platform 4 corresponds to each of the high-strength, high-temperature resistant pressure heads 53 on the top of the furnace body 1.

[0033] Vacuuming and heating stage: Vacuum system 2 evacuates the inner cavity of furnace body 1 to the set pressure, such as 10. -3 Pa, the first heater 31 heats uniformly along the outer circumference of the sealed isolation chamber 9, and the second heater 32 provides compensating heating from the top. The second heater 32 increases the heating power density at the clearance gap to compensate for the heat loss caused by the high-strength, high-temperature resistant pressure head 53 blocking, so that the temperature uniformity inside the furnace reaches ±7.5℃. The sealed isolation chamber 9 physically isolates the quartz product from the heater. The volatiles and oxide dust released by the quartz product at high temperature are confined inside the sealed isolation chamber 9, reducing the impact on the circumferential heater 31.

[0034] Hot pressing stage: The control system monitors the melting state of the quartz products at each station in real time and indirectly determines this by monitoring the pressure head subsidence through the displacement detection unit. When the quartz product at a certain station reaches a softened state, the control system independently activates the drive assembly 51 for that station, applying the set pressure through the pressure rod 52 and the high-strength, high-temperature resistant pressure head 53. During this process: The dynamic sealing device between the pressure rod 52 and the top of the furnace body 1, consisting of an O-ring rubber seal 72 and a lip seal 73, maintains the vacuum environment inside the furnace during the reciprocating motion of the pressure rod. The upper hard felt plate 81, lower hard felt plate 82, soft felt layer 83, first heat insulation hard felt cylinder 84, second heat insulation hard felt cylinder 85, and support plate 86 of the heat insulation device block the heat conducted from the pressure rod 52 from the furnace step by step, so that the ambient temperature at the dynamic sealing device is kept within the safe operating range of the sealing ring. The pressure detection unit and displacement detection unit of each station feed back data to the control system in real time. The control system dynamically adjusts the pressure and displacement of each station according to the preset process curve until all stations reach the target deformation height.

[0035] Unloading stage: After hot pressing is completed, the control system controls each drive component 51 to release pressure and lift the pressure rod 52. After the furnace body 1 cools to room temperature, the lifting device 11 drives the lower cover 10 to descend, and the translation vehicle 12 moves the support platform 4 out to remove the finished product.

[0036] The above working process shows that the various technical features of the present invention support each other functionally. The independent support frame provides a structural basis for long-term centering accuracy, the independent control system provides a control basis for differentiated processes, the combination of dynamic sealing and thermal insulation provides a guarantee for sealing and thermal insulation reliability in high-temperature environments, the layout of the sealed isolation chamber and the heater provides a dual guarantee for temperature uniformity and heater life, and the lifting and translating discharge structure provides operational feasibility for material loading and unloading of large equipment. All features together constitute an organic whole that cannot be separated or understood.

[0037] To further illustrate the technical effects and working principle of the present invention, several embodiments and comparative examples are provided below.

[0038] Example 1: Three-station quartz cylinder shaping equipment like Figures 1-2 As shown, this embodiment provides a vacuum pressure integrated hot pressing device for quartz products. This hot pressing device performs high-temperature pressure shaping on a three-station quartz cylinder, wherein: The furnace body 1 has a diameter of φ3000mm and a total height of 3200mm (including upper and lower covers). The effective process area has a diameter of φ1800mm × H600mm. The inner wall is equipped with a carbon felt insulation layer with a thickness of 240mm. A lower cover 10 is installed at the bottom of the furnace body 1. The lower cover 10 has a diameter of φ3000mm and a thickness of 80mm. It adopts a double-layer water-cooled structure and is reinforced with reinforcing ribs to ensure its rigidity and strength. A lifting device 11 and a translation trolley 12 are connected below the lower cover 10. A support platform 4 is fixedly installed on the lower cover 10. The support platform 4 has three workstations, which can process three quartz cylinders of different specifications (φ200 × H600mm respectively) simultaneously. The ingots are φ230×H550mm and φ300×H400mm. The pressurized start-up temperature is 1750 degrees Celsius. All ingots are hot-pressed and shaped to a drum shape with a height of H300mm, matching the shape of the mold cavity. The lifting device 11 uses four synchronous hydraulic cylinders, each with a thrust of 150kN and a stroke of 1200mm, guided by four sets of linear guides. The translation cart 12 is motor-driven, with a travel speed of 2m / min and a track length of 8m. The vacuum system 2 uses a mechanical pump (pumping speed 300L / s), a Roots pump (pumping speed 1200L / s), and a diffusion pump (pumping speed 50000L / s), achieving an ultimate vacuum of 5×10⁻⁶. -5 Pa, in which the mechanical pump and the Roots pump are connected in series to form a two-stage pump group, and the diffusion pump is connected in series or in parallel with the two-stage pump group. Based on the actual situation, the series and parallel states of the diffusion pump and the two-stage pump group can be switched at any time through the control system. Three mechanical hot pressing devices are respectively installed on the top of the furnace body 1 for the three workstations. The three mechanical hot pressing devices are all installed on independent support frames 6. The support frame 6 consists of four columns and a top mounting platform 61. The lower ends of the columns are fixed to the ground and are completely separated from the structure of the furnace body 1. Each mechanical hot pressing device is equipped with an independent hydraulic cylinder with a maximum pressure of 50kN and a stroke of 400mm. The mechanical hot pressing device includes a drive assembly 51, a pressure rod 52, and a high-strength high-temperature resistant pressure head 53. The pressure rod 52 adopts a combination structure of graphite and 304 stainless steel. The graphite section has a diameter of 180mm and a length of 700mm, and the stainless steel section has a diameter of 120mm and a length of 500mm. The high-strength high-temperature resistant pressure head 53 is made of high-purity graphite material and is threaded to the lower end of the pressure rod 52. It should be noted that each pressure rod 52 is equipped with a cooling water circulation structure inside to remove the heat conducted from the pressure rod 52 and prevent the sealing ring from being damaged by excessive heat. A dynamic sealing device is provided between each pressure rod 52 and the top of the furnace body 1. The dynamic sealing device includes a clamping mechanism 71, multiple sets of sealing rings (heat-resistant rubber + stainless steel frame), and a separating ring 74 disposed between each sealing ring. The surfaces of the pressure rod 52 that mate with each sealing ring are ground to a surface roughness of Ra0.8. Figure 2As shown, each set of dynamic sealing devices includes four sets of O-ring rubber seals 72 (made of fluororubber or perfluoroether rubber, with a temperature resistance of not less than 250℃) and two sets of skeleton lip seals 73 (polytetrafluoroethylene + fluororubber + stainless steel skeleton). A partition ring 74 is provided between adjacent O-ring rubber seals 72, between adjacent O-ring rubber seals 72 and lip seals 73, and between adjacent lip seals 73. A pressing mechanism 71 is provided on the upper side of the seals to press each seal. A thermal insulation device is installed below the dynamic sealing device. According to actual measurements, when the temperature inside the furnace body 1 reaches 1750℃, the ambient temperature outside the thermal insulation device (where the dynamic sealing device is installed) is stable within the range of 180℃-250℃, which is far below the upper limit of the long-term operating temperature of the fluororubber sealing ring (250℃), ensuring the safe and reliable operation of the fluororubber sealing ring. The total thickness of the thermal insulation device is 240mm, of which the thickness of the upper hard felt plate 81 is 60mm, the thickness of the soft felt layer 83 is 120mm, the thickness of the lower hard felt plate 82 is 60mm, the height of the first thermal insulation hard felt cylinder 84 is 200mm, the height of the second thermal insulation hard felt cylinder 85 is 120mm, and the thickness of the support plate 86 is 20mm. The inner cavity of the furnace body 1 is also equipped with a sealed isolation chamber 9. The sealed isolation chamber 9 is made of carbon-carbon composite material, has a cylindrical structure, a wall thickness of 30mm, a height of 650mm, and is fitted around the three quartz cylinders to be processed. Its lower end is sealed to the support platform 4, and its upper end is sealed to the inner side of the top of the furnace body 1. The inner cavity of the furnace body 1 is also equipped with a first heater 31 and a second heater 32. The first heater 31 consists of 24 cylindrical graphite heating rods evenly distributed along the outer circumference of the sealed isolation chamber 9, with a total power of 500kW. The second heater 32 is located on the top inner side of the furnace body 1, distributed in a serpentine or spiral shape, with a power of 250kW. Three clearance notches are set according to the three pressure head positions. The cross-sectional area of ​​the second heater 32 at the clearance notches is reduced by 10-25% to compensate for the heating power density. The control system adopts a distributed architecture, with each workstation equipped with an independent PID controller. The pressure sensor used as the pressure detection unit is a strain gauge sensor, which is installed at the connection between the hydraulic cylinder and the pressurizing device. At the same time, an oil pressure sensor is set in the oil circuit to monitor and control the pressure sensor. The displacement sensor used as the displacement detection unit is a magnetostrictive displacement sensor with an accuracy of 0.01mm.

[0039] Work process: (1) Place the product molds at the three work stations of the support platform, place three quartz cylinders of different specifications in the graphite mold, drive the lower cover 10 to rise and seal with the bottom of the furnace body 1, and adjust the initial position of the pressure head to 20mm away from the upper surface of the quartz cylinder. (2) Start the vacuum system 2 and evacuate to 10.-3 Pa; (3) Introduce high-purity nitrogen (99.999% purity) to 20 Pa; (4) Start the heater and heat up according to the set program: Room temperature - 1000℃, heating rate 10℃ / min; Heating rate from 1000℃ to 1400℃: 5℃ / min; The temperature rises from 1400℃ to 1750℃ at a rate of 2℃ / min. After reaching the set temperature, the temperature is held for 30 minutes to allow the quartz material to soften fully and uniformly. Displacement sensors at each workstation monitor changes in the pressure head position in real time. The control system then activates the drive assembly 51 at that workstation to initiate pressurization according to a preset program. Station 1 (φ200×H600mm): Pressurization is started when the temperature reaches 1750℃. The initial pressure is set to 10000N and continues for 15 minutes. Then the pressure is gradually increased to 30000N and continues for 15 minutes. Station 2 (φ230×H550mm): Pressurization is initiated when the temperature reaches 1750℃, with an initial pressure set at 10000N. After 15 minutes, the pressure is gradually increased to 30000N and maintained for 15 minutes. Station 3 (φ300×H400mm): Pressurization is initiated when the temperature reaches 1750℃, with an initial pressure set at 10000N. After 15 minutes, the pressure is gradually increased to 40000N and maintained for 15 minutes. During the pressurization process, the displacement sensors at each station monitor the descent distance of the pressure head in real time. At any time, when the pressure head at each station descends to the designated position (target height 300mm + 20mm waiting position), the pressurization will automatically stop. (5) After pressurization is completed, the pressure head is moved up to release the pressure; (6) Continue cooling to room temperature, open the lower cover 10, move the support platform 4 out using the translation cart 12, and take out the finished product; (7) Record the total processing time, energy consumption and product qualification rate. The results are shown in Table 1.

[0040] Example 2: Three-station quartz cylinder shaping equipment This embodiment uses the same equipment as in Embodiment 1 to process three quartz cylinders of different specifications (φ200×H600mm, φ230×H550mm, and φ300×H400mm respectively). Pressurization is started at 1350℃, and the cylinders are hot-pressed and shaped to heights of H450mm, H500mm, and H350mm respectively. The mold is a regular straight cylinder.

[0041] Work process: (1) Same as Example 1; (2) Same as Example 1; (3) Same as Example 1; (4) Start the heater and heat and pressurize it according to the set program: Room temperature - 1000℃, heating rate 10℃ / min; Heating rate from 1000℃ to 1350℃: 5℃ / min; Hold at 1350℃ for 30min; Start pressurization, set the pressure to 10000N, and continue for 30min. Heating rate from 1350℃ to 1550℃: 2℃ / min; hold at 1550℃ for 30min; increase pressure to 50000N; hold for 30min. During the pressurization process, the displacement sensors at each station monitor the descent distance of the pressure head in real time. At any time, when the pressure head at each station descends to the designated position (φ200×H600mm descends to H450mm, φ230×H550mm descends to H500mm, φ300×H400mm descends to H350mm), the pressurization will automatically stop. (5) After pressurization is completed, the pressure head is moved up to release the pressure; (6) Continue cooling to room temperature, open the lower cover 10, move the support platform 4 out using the translation cart 12, and take out the finished product; (7) Record the total processing time, energy consumption and product qualification rate. The results are shown in Table 1.

[0042] Comparative Example 1-1 Three quartz cylinders (same specifications, same mold, and same drum shape requirements as in Example 1) were processed using a single-station ordinary equipment (equipment without a hot pressing device). The heating temperature was 1850℃. The total processing time, energy consumption, and product qualification rate were recorded. The results are shown in Table 1.

[0043] Comparative Examples 1-2 Three quartz cylinders (same specifications, same mold, and same drum shape requirements as in Example 1) were processed using a single-station equipment with a hot pressing device. The total processing time, energy consumption, and product qualification rate were recorded, and the results are shown in Table 1.

[0044] Comparative Examples 1-3 Three quartz cylinders (same specifications, same mold, and same drum shape requirements as in Example 1) were processed simultaneously using ordinary multi-station equipment (equipment without hot pressing device). The heating temperature was 1800-1900℃. The total processing time, energy consumption, and product qualification rate were recorded. The results are shown in Table 1.

[0045] Comparative Example 2-1 Three quartz cylinders (same specifications, same mold, same requirements as in Example 2) were processed using a single-station ordinary equipment (equipment without a hot pressing device) and heated to 1850℃. The total processing time, energy consumption, and product qualification rate were recorded, and the results are shown in Table 2.

[0046] Comparative Example 2-2 Three quartz cylinders (same specifications, same molds, and same requirements as in Example 2) were processed using a single-station equipment with a hot pressing device. The total processing time, energy consumption, and product qualification rate were recorded, and the results are shown in Table 2.

[0047] Comparative Examples 2-3 Three quartz cylinders (same specifications, same molds, and same requirements as in Example 2) were processed simultaneously using ordinary multi-station equipment (equipment without hot pressing device) at a heating temperature of 1850℃. The total processing time, energy consumption, and product qualification rate were recorded, and the results are shown in Table 1.

[0048] Table 1. Experimental results of Example 1 and Comparative Examples 1-1 to 1-3 (with drum-shaped requirements) project Example 1 Comparative Example 1-1 Comparative Examples 1-2 Comparative Examples 1-3 Total processing time (h) 70 180 170 72 Unit product energy consumption benchmark 2.8 times the benchmark 2 times the benchmark 1x benchmark Product pass rate (%) 96 70 (High side defect rate) 96 70 (High side defect rate) Table 2. Experimental results of Example 2 and Comparative Examples 2-1 to 2-3 (height only required) project Example 2 Comparative Example 2-1 Comparative Example 2-2 Comparative Examples 2-3 Total processing time (h) 60 180 144 72 Unit product energy consumption benchmark 3 times the benchmark 2 times the benchmark 1.3 times the benchmark Product pass rate (%) 96 96 96 96 As shown in Table 1, for multi-specification quartz products requiring processing into a drum shape (complex side curves), the pass rate of single-station hot-pressing equipment (Comparative Example 1-1) and ordinary multi-station hot-pressing equipment (Comparative Example 1-3) is only 70%, with the main drawback being a high side defect rate, failing to meet the requirements of complex shapes. While single-station hot-pressing equipment (Comparative Example 1-2) can achieve a pass rate of 96%, the total processing time is as long as 170 hours, and the energy consumption per unit product is twice that of Example 1 of this invention. In contrast, Example 1 of this invention uses an independently controlled three-station hot-pressing device. Under the harsh condition of simultaneously processing three different specifications of products, the pass rate also reaches 96%, and the total processing time is only 70 hours, with the energy consumption per unit product being the baseline value (lowest). This demonstrates that this invention, through an independent control system that differentiates pressurization based on the real-time melting state of the quartz products at each station, successfully solves the problem of process synchronization in the same furnace processing of multi-specification products, significantly shortening the processing cycle and reducing energy consumption while ensuring a high pass rate.

[0049] As shown in Table 2, for straight cylindrical products requiring only height and simple shape, the pass rate of each device can reach 96%. However, the total processing time for single-station hot-pressing equipment (Comparative Example 2-1) and single-station hot-pressing equipment (Comparative Example 2-2) is as long as 180 hours and 144 hours respectively, and the energy consumption per unit product is 3 times and 2 times that of Example 2 of this invention, respectively. Although ordinary multi-station hot-pressing equipment (Comparative Example 2-3) can process in parallel, the total processing time is 72 hours, and the energy consumption per unit product is still 1.3 times that of Example 2. In contrast, the total processing time of Example 2 of this invention is only 60 hours, and the energy consumption per unit product is the baseline value (lowest). It can be seen that even in conventional production, the multi-station independent control hot-pressing device of this invention achieves the optimal solution for the comprehensive benefits of time, energy consumption, and quality through parallel operation, uniform temperature field, and precise control.

[0050] In summary, this invention, through an independently controlled multi-station hot pressing device, combined with an independent support frame, dynamic sealing and thermal insulation, a sealed isolation chamber, and a top-compensating heater, achieves a stable yield rate of 96% (compared to only 70% for ordinary equipment) when processing products of various specifications and complex shapes in the same furnace. In conventional processing, processing time is reduced by more than 58% compared to single-station equipment and by 16.7% compared to ordinary multi-station equipment. Energy consumption is reduced by 50-66% compared to single-station equipment and by 23% compared to ordinary multi-station equipment. Objective data fully demonstrates the significant superiority of this invention in processing efficiency, energy saving, and process adaptability, achieving unexpected technical results.

[0051] The above provides a detailed description of a multi-station vacuum pressure integrated hot pressing device for quartz products provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A multi-station integrated vacuum pressure hot pressing device for quartz products, characterized in that, include: The furnace body has an insulation layer fixedly installed on its inner side wall; A vacuum system, connected to the furnace body, is used to evacuate the inner cavity of the furnace. The support platform, located inside the furnace body, is used to simultaneously support multiple quartz product preforms; The heater is located inside the furnace body and is arranged around the quartz product preform on the support platform; Multiple mechanical hot pressing devices are installed on the top of the furnace body, and each of the multiple mechanical hot pressing devices is set in a corresponding manner to the quartz product preforms on the support platform, for hot pressing treatment of the quartz product preforms. The control system is independently connected to multiple mechanical hot pressing devices. It is used to independently control the pressure, displacement and timing of the corresponding mechanical hot pressing devices based on the real-time melting state characterized by the change in the modified height of each quartz product preform on the support platform.

2. The vacuum pressure integrated hot pressing equipment according to claim 1, characterized in that, The mechanical hot pressing device includes a drive assembly, a pressure rod, and a high-strength, high-temperature resistant pressure head. The lower end of the pressure rod passes through the top of the furnace body and is connected to the high-strength, high-temperature resistant pressure head at that end. The upper end of the pressure rod is connected to the drive assembly, and the drive assembly is connected to the control system. The control system controls the drive assembly to realize the action of the pressure rod.

3. The vacuum pressure integrated hot pressing equipment according to claim 2, characterized in that, It also includes a support frame that is separate from and independently set up from the furnace body. The lower end of the support frame is fixed to the ground or equipment foundation, and the upper end of the support frame is provided with an installation platform. The drive components of multiple mechanical hot pressing devices are fixedly installed on the installation platform. A through hole is opened on the top of the furnace body corresponding to the position of each mechanical hot pressing device for the pressure rod to pass through. A dynamic sealing device is provided between the pressure rod and the through hole.

4. The vacuum pressure integrated hot pressing equipment according to claim 3, characterized in that, A dynamic sealing device is provided between the mechanical hot pressing device and the top of the furnace body. The dynamic sealing device includes a pressing mechanism and multiple sets of sealing rings. The pressing mechanism is located on the upper side of the multiple sets of sealing rings to prevent the sealing rings from falling off and deforming. A separation ring is provided between the pressing mechanism and its adjacent sealing rings, as well as between two adjacent sealing rings. The sealing rings include multiple sets of O-ring rubber sealing rings and multiple sets of lip sealing rings with skeletons distributed from top to bottom.

5. The vacuum pressure integrated hot pressing equipment according to claim 4, characterized in that, It also includes a thermal insulation device located below the dynamic sealing device. The thermal insulation device includes an upper hard felt board, a lower hard felt board, a soft felt layer, a first thermal insulation hard felt cylinder, a second thermal insulation hard felt cylinder, and a support plate. The support plate is sleeved on the pressure rod. The lower hard felt board, the second thermal insulation hard felt cylinder, the upper hard felt board, and the first thermal insulation hard felt cylinder are arranged sequentially from bottom to top on the upper part of the support plate and sleeved on the pressure rod. The soft felt layer is arranged between the upper hard felt board and the lower hard felt board and is located outside the second thermal insulation hard felt cylinder. The first thermal insulation hard felt cylinder is T-shaped to cover the exposed part of the pressure rod and block axial heat conduction.

6. The vacuum pressure integrated hot pressing equipment according to claim 1, characterized in that, It also includes a sealed isolation chamber located inside the furnace body and made of carbon material. The sealed isolation chamber is set between the heater and multiple quartz product preforms to reduce the contamination of the heater by the by-products generated during the processing of the quartz product preforms.

7. The vacuum pressure integrated hot pressing equipment according to claim 6, characterized in that, The heater includes a first heater arranged along the circumferential direction of the outer side of the sealed isolation chamber and a second heater located at the top of the inner side of the furnace body in a serpentine or spiral shape.

8. The vacuum pressure integrated hot pressing equipment according to claim 1, characterized in that, It also includes a pressure detection unit and a displacement detection unit, which are respectively connected to the control system. The pressure detection unit is used to monitor the pressure changes of each mechanical hot pressing device in real time, and the displacement detection unit is used to monitor the changes in the deformation height of the quartz product preform in real time.

9. The vacuum pressure integrated hot pressing equipment according to claim 1, characterized in that, The furnace body has a bottom cover for sealing the lower side of the furnace body. A lifting device and a trolley are connected below the bottom cover. A support platform is fixedly installed on the bottom cover. The output end of the lifting device is connected to the bottom of the bottom cover and is used to drive the bottom cover to move up and down in the vertical direction to open and seal the bottom of the furnace body. The trolley is located below the lifting device. The base of the lifting device is fixedly installed on the trolley. The bottom of the trolley is equipped with wheels and a driving mechanism for driving the trolley to move along a horizontal track, thereby realizing the horizontal transfer of the bottom cover and the support platform.

10. The vacuum pressure integrated hot pressing equipment according to claim 1, characterized in that, The vacuum system includes a secondary pump set and a diffusion pump connected in series or in parallel with the secondary pump set. The secondary pump set includes a mechanical pump and a Roots pump connected in series. An exhaust port is provided on the side of the furnace body. The exhaust port is connected to the vacuum system through an exhaust pipe. A vacuum valve is provided on the exhaust pipe.

Images