CdTe power generation glass vacuum coating ceramic roller online self-cleaning and anti-pollution system and method

Abstract

This invention discloses an online self-cleaning and anti-contamination system and method for ceramic rollers used in vacuum coating of cadmium telluride photovoltaic glass. The system includes multiple high-temperature ceramic rollers arranged parallel to each other along the glass substrate transport direction. Each high-temperature ceramic roller is mounted at both ends to fixed supports on both sides of the main coating cavity of the equipment via bearings. The system also includes three synergistic components with closed-loop coupling feedback of thermodynamics and mechanodynamics, including a stator-side thermodynamic anti-sublimation shielding ring assembly located between the fixed supports and the ends of the high-temperature ceramic rollers. The purpose of this invention is to solve the problems in the vacuum sublimation coating production process of cadmium telluride photovoltaic glass, such as bearing jamming caused by the penetration and condensation of gaseous molecules at the ends of the high-temperature ceramic rollers, and transport instability caused by the hardening of solid deposits at the central support points. Furthermore, conventional physical cleaning methods require shutdown and vacuum breaking, severely restricting continuous production capacity.

Description

Technical Field

[0001] This invention relates to the technical field of photovoltaic thin-film battery preparation, specifically to an online self-cleaning and anti-contamination system and method for cadmium telluride photovoltaic glass vacuum coating ceramic roller. Background Technology

[0002] In the continuous vacuum sublimation coating process of cadmium telluride large-area power generation glass, the high-temperature ceramic roller carrying the glass substrate is in a low-pressure and high-temperature sublimation environment for a long time, facing multi-dimensional physical pollution problems.

[0003] First, at the end of the ceramic roller, free cadmium telluride gaseous molecules diffuse towards the relatively cooler bearing area. Since the fluid dynamics continuous medium assumption does not apply in a high vacuum environment, conventional mechanical contact seals or physical baffles are at risk of wear and are difficult to block rarefied gases that follow the Knudsen diffusion law, causing cadmium telluride molecules to condense in the solid phase inside the bearing. This increases rotational resistance and may cause bearing jamming and motor overload.

[0004] Secondly, at the support point in the middle of the ceramic roller, under the long-term effect of the substrate's gravity and rolling friction, cadmium telluride is prone to deposit and harden. If conventional mechanical scraper is used for cutting, it is easy to wear down the ceramic substrate, and there is a possibility that the drive motor will stop due to excessive cutting resistance torque. Furthermore, the growth of the deposits will cause transmission instability and affect the surface quality of the glass substrate.

[0005] Finally, in-situ cleaning within the vacuum chamber is limited by operating conditions: the lack of a fluid medium under low pressure makes it difficult to utilize pressure difference to generate negative pressure suction for pneumatic collection; simultaneously, the cadmium telluride debris peeled off the roller surface carries heat, and if directly discharged into mechanical screw conveyors or other extrusion conveyors, the powder is prone to thermal pressing, sintering, and agglomeration under physical compression, affecting the smooth flow of waste discharge pipelines. Existing maintenance methods typically rely on periodic shutdowns, vacuum disruption, and disassembly for offline cleaning, which makes it difficult to achieve online, continuous pollution prevention and waste discharge, impacting the continuous operating capacity and overall utilization rate of the equipment. Summary of the Invention

[0006] This invention provides an online self-cleaning and anti-contamination system and method for ceramic rollers used in vacuum sublimation coating of cadmium telluride photovoltaic glass. The purpose is to solve the problems in the vacuum sublimation coating production process of cadmium telluride photovoltaic glass, such as bearing jamming caused by the penetration and condensation of gaseous molecules at the end of the high-temperature ceramic roller for transmission, and transmission instability caused by the hardening of solid deposits at the middle support point. Furthermore, conventional physical cleaning methods require stopping the machine to break the vacuum, which seriously restricts the continuous production capacity.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An online self-cleaning and anti-contamination system for cadmium telluride power generation glass vacuum coating ceramic rollers includes: multiple high-temperature ceramic rollers arranged parallel to each other along the glass substrate transport direction; each high-temperature ceramic roller is mounted at both ends to fixed supports on both sides of the main coating cavity of the equipment via bearings; the system also includes three synergistic components with closed-loop coupling feedback of thermodynamics and mechanodynamics: a stator-side thermodynamic anti-sublimation shielding ring assembly disposed between the fixed supports and the ends of the high-temperature ceramic rollers; a differential thermal expansion induced peeling and adaptive scraping assembly disposed at the intermediate support point of the high-temperature ceramic rollers; and a solid contaminant cold phase solidification and airless mechanical collection assembly disposed below the differential thermal expansion induced peeling and adaptive scraping assembly.

[0008] In one aspect of the invention, the stator-side thermodynamic anti-sublimation shielding ring assembly includes: A stator-side thermodynamic anti-sublimation shielding ring is rigidly anchored to the fixed bracket. The shielding ring is sleeved on the outer side of the end of the continuously rotating high-temperature ceramic roller for transmission and forms a non-contact radial micro-gap with the wall surface of the high-temperature ceramic roller for transmission. The inner surface of the shielding ring is machined with a labyrinthine annular toothed groove with a multi-stage trapezoidal cross section. A resistance heating element and a temperature sensor are embedded inside the shielding ring.

[0009] In one aspect of the invention, the system further includes a control system connected to the resistive heating element and the temperature sensor, wherein the surface temperature of the stator-side thermodynamic anti-sublimation shielding ring is maintained by the control system in a high-temperature range of 450°C to 500°C, so as to construct a gas-solid phase change reverse gradient blocking mechanism within the radial micro-gap.

[0010] In one aspect of the invention, the surface of the intermediate support site of the high-temperature ceramic roller for transmission is coated with a micron-scale anisotropic thermal expansion transition layer. The thermal expansion coefficient of this transition layer is different from that of the substrate of the high-temperature ceramic roller for transmission and different from that of condensed cadmium telluride. The high-temperature ceramic roller for transmission is provided with a heating core inside. The heating core is used to output a transient thermal pulse to the support site when an abnormal rotational resistance is detected, thereby inducing microcracks in the solid deposits through interfacial shear thermal stress between the heterogeneous materials.

[0011] In one aspect of the invention, the differential thermal expansion induced peeling and adaptive scraping assembly further includes a clamp base fixed below the support point, the clamp base being pivotally connected to a pair of adaptive mechanical scraping plates coated with a high-temperature wear-resistant titanium aluminum nitride coating; the adaptive mechanical scraping plates apply a constant normal force to the support point through a nickel-based disc-shaped high-temperature spring, so as to cut away the solid attachments that have generated microcracks through rotational shear force.

[0012] In one aspect of the invention, the solid contaminant cold phase solidification and airless mechanical collection assembly is arranged directly below the adaptive mechanical scraper, including an inverted conical gravity guide receiving groove and a horizontal stainless steel conveying pipe connected to its bottom; the stainless steel conveying pipe is internally fitted with a shaftless mechanical spiral conveying rod driven by an external servo motor, and the stainless steel conveying pipe is externally covered with an independent circulating cooling jacket.

[0013] In one aspect of the invention, the end of the stainless steel conveying pipe is connected to a vacuum lock dust collection tank with dual vacuum valves, the dual vacuum valves including a top baffle valve and a bottom discharge valve, for discharging cooled and solidified solid waste while maintaining the vacuum level of the main cavity of the equipment coating.

[0014] In another aspect, the present invention also relates to an online self-cleaning and anti-fouling method for a cadmium telluride photovoltaic glass vacuum coating ceramic roller, comprising the following steps: A reverse gradient blocking thermodynamic field is established to construct a non-contact thermal radiation labyrinth field between a stationary fixed support and the end of a rotating high-temperature ceramic roller for transmission. Activate the cold phase solidification and mechanical waste discharge path, and start the bottom airless mechanical collection component and circulating cooling jacket; Thermodynamic compensation and stress-induced delamination are performed, system resistance is monitored, and thermal stress is induced at the interface of heterogeneous materials by transient thermal pulses, causing microcracks to be generated in the solid attachments. In-situ dynamic cutting and adaptive scraping utilize the constant positive pressure of the adaptive mechanical scraping plate and the rotating shearing force of the high-temperature ceramic roller for transmission to cut away solid deposits with microcracks. Gravity-guided and anti-sintering conveying of solid waste introduces detached debris with high enthalpy into a stainless steel conveying pipe and performs forced heat exchange cooling during the physical pushing process to achieve cold phase solidification. Vacuum lock and closed-loop sewage discharge allow for the discharge of cooled and solidified solid waste without compromising the vacuum level of the main cavity of the equipment's coating process.

[0015] In one aspect of the present invention, the specific execution logic for performing thermodynamic compensation and stress-induced delamination, monitoring system resistance, and inducing thermal stress at the interface of heterogeneous materials through transient thermal pulses to generate microcracks in the solid attachment includes: The operating current of the motor driving the high-temperature ceramic roller for transmission is monitored in real time. When the current pulsation exceeds the set reference value and reaches the threshold range, a high-level pulse is output to the heating core inside the high-temperature ceramic roller for transmission. Stress is generated by the difference in the amount of expansion of the micron-level anisotropic thermal expansion transition layer, the substrate and the cadmium telluride deposit after heating, thereby cracking the solid deposit to complete the pretreatment for peeling.

[0016] In one aspect of the invention, the gravity-guided and anti-sintering conveying of the solid waste, which guides the detached debris with high enthalpy into a stainless steel conveying pipe and performs forced heat exchange cooling during the physical pushing process to achieve cold phase solidification, includes the following specific execution logic: After being cut off, the high-temperature solid debris falls into the stainless steel conveying pipe under the action of gravity. During the process of the shaftless mechanical screw conveyor pushing the material forward, the circulating cooling jacket forces the high-temperature material in the pipe to cool down, changing the rheological properties of the solid debris to keep it in a loose particle state, thereby preventing the solid debris from undergoing hot pressing sintering during mechanical extrusion.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The technical solution of this invention achieves online anti-fouling and self-cleaning of equipment in a vacuum sublimation coating environment through the synergy of thermodynamics and mechanical dynamics. First, by establishing a reverse gradient blocking thermodynamic field, the system replaces conventional contact sealing. Utilizing the principle of gas-solid phase change, it causes cadmium telluride molecules attempting to invade the bearing area to undergo secondary sublimation, constructing a bearing protection barrier without mechanical contact and reducing the risk of motor overload shutdown caused by condensation. Second, thermodynamic compensation and stress-induced peeling combined with in-situ dynamic adaptive scraping change the cutting method that relies on a single mechanical force. The system uses transient thermal pulses to induce thermal stress at the interface of heterogeneous materials, causing microcracks to form inside the solid accumulations at the support sites. Subsequently, under the combined action of constant normal pressure and the rotating shear force of the ceramic roller, these microcracks are cut away. This removes the accumulations, ensures the transport of the glass substrate, and reduces mechanical resistance torque and equipment wear. Finally, by activating the cold phase solidification path and implementing gravity-guided flow and anti-sintering conveying, this solution adapts to conditions where fluid media are absent under vacuum and low pressure. During the mechanical spiral extrusion process, the heated detached debris is cooled to a granular state through heat exchange in the circulating cooling jacket, reducing the possibility of thermal sintering of the powder under pressure, which could affect the conveying pipeline. The coordinated operation of these steps, while maintaining the vacuum and thermal balance of the main cavity, transforms offline cleaning during shutdown into online processing during production, which is beneficial for improving the operational stability and equipment capacity of the continuous coating production line. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the internal environment and transmission architecture of the main cavity of the cadmium telluride vacuum sublimation coating equipment of the present invention.

[0020] Figure 2 This is a structural breakdown and partial cross-sectional schematic diagram of the stator-side thermodynamic anti-sublimation shielding ring assembly and the end of the high-temperature ceramic roller for transmission in this invention.

[0021] Figure 3 This is a schematic diagram comparing the overall structure and the contamination widening imprint of the high-temperature ceramic roller for transmission after it is assembled with the stator-side thermodynamic anti-sublimation shielding ring according to the present invention.

[0022] Figure 4 This is a schematic diagram showing the spatial distribution of the intermediate support point and the end bearing of the high-temperature ceramic roller for transmission according to the present invention.

[0023] Figure 5 This is a flowchart of an online self-cleaning and anti-contamination method for a cadmium telluride power generation glass vacuum coating ceramic roller according to the present invention.

[0024] Figure 6 This is a schematic diagram showing the positional relationship between the scraping plate and the support point in this invention.

[0025] Figure 7 This is a side view of the positional relationship between the fixing component and the ceramic roller of the present invention.

[0026] Figure 8 This is a schematic diagram of the overall structure of the ceramic roller of the present invention.

[0027] In the diagram, 101-Main cavity for equipment coating, 102-Glass substrate, 103-Supporting point, 104-Ceramic roller, 105-Fixed bracket, 106-Cadmium sulfide evaporation path, 107-Material, 108-Heating core, 109-Reverse sublimation shielding ring, 110-Transition layer, 112-Scraping plate, 113-Nickel-based disc-shaped high-temperature spring. Detailed Implementation

[0028] The present invention will be further described below with reference to embodiments. These embodiments are merely some, not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the protection scope of the present invention.

[0029] Example 1 Please see Figures 1-8As shown, this embodiment discloses the overall physical architecture of an online self-cleaning and anti-fouling system for a cadmium telluride photovoltaic glass vacuum coating ceramic roller 104. The system is installed inside the main coating chamber 101 of the equipment and includes multiple high-temperature ceramic rollers 104 arranged parallel to each other along the transport direction of the glass substrate 102. Both ends of each high-temperature ceramic roller 104 are respectively mounted on fixed supports 105 on both sides of the main coating chamber 101 of the equipment via bearings.

[0030] To achieve closed-loop coupled feedback between thermodynamics and mechanical dynamics within the system, this system comprises three coordinating components: The first component is a stator-side thermodynamic anti-sublimation shielding ring 109 component, which is disposed between the fixed bracket 105 and the end of the high-temperature ceramic roller 104 for transmission. The second component is a differential thermal expansion induced peeling and adaptive scraping component, which is set at the middle support point 103 of the high temperature ceramic roller 104 for transmission. The third component is a solid pollutant cold phase solidification and airless mechanical collection component, which is located directly below the differential thermal expansion induced peeling and adaptive scraping component.

[0031] Based on the above system architecture, this embodiment provides an online self-cleaning and anti-fouling method for the cadmium telluride photovoltaic glass vacuum coating ceramic roller 104. The method is logically divided into the following six mutually coupled steps: Step S1: Establish a reverse gradient blocking thermodynamic field: Construct a non-contact thermal radiation labyrinth field between the stationary fixed support 105 and the end of the rotating high-temperature ceramic roller 104 for transmission.

[0032] Specifically, in the initial startup phase of the cadmium telluride (CdT) photovoltaic glass vacuum sublimation coating production line, the system first executes step S to establish a reverse gradient blocking thermodynamic field. This step aims to solve the technical problem of Knudsen diffusion and condensation of gaseous CdT molecules in the bearing area at the end of the high-temperature ceramic roller 104 used for transport under high vacuum conditions. Under a local vacuum partial pressure of 0.5 Pa, conventional contact-type physical seals would experience dry friction wear due to lack of gas lubrication. Therefore, this solution uses a stationary alumina ceramic shielding ring to construct a non-contact radial micro-gap. The system maintains the absolute temperature of the shielding ring surface at 673.15 Kelvin (i.e., 400 degrees Celsius) through closed-loop control. At this point, the Knudsen sublimation rate equation based on gas molecular dynamics is applied. This formula expresses the net sublimation flux as the CdT evaporation coefficient multiplied by the difference between the saturated vapor pressure and the local vacuum partial pressure, divided by the square root of the product of twice pi, molar mass, ideal gas constant, and surface absolute temperature. The reason for adopting this calculation logic is that the continuous medium fluid dynamics theory is no longer applicable under extremely low pressures, and the direction of gas-solid conversion must be quantified from the perspective of microscopic molecular collisions and phase transition thermodynamics. Using specific engineering data for calculation, the evaporation coefficient of cadmium telluride is taken as 0.45, the saturated vapor pressure at 673.15 Kelvin is 1.8 Pa, the molar mass is 0.24 kg / mol, and the ideal gas constant is taken as 8.314 joules / mol Kelvin. Since the set saturated vapor pressure of 1.8 Pa is greater than the partial pressure of vacuum in the cavity by 0.5 Pa, the calculated net sublimation flux within the gap is positive, specifically 0.00637 kg / m² / s. This positive flux, from a physical perspective, causes any free-state molecule entering the gap to increase its kinetic energy and undergo secondary sublimation upon collision with the inner wall of the high-temperature shielding ring, and is thus repelled out of the micro-gap. The beneficial effect of this mechanism is that it blocks the formation path of solid deposits inside the bearing without increasing additional mechanical friction resistance, thus reducing the probability of the drive motor being overloaded due to end jamming.

[0033] Step S2, Activate cold phase curing and mechanical waste removal path: Start the bottom airless mechanical collection component and circulating cooling jacket.

[0034] Specifically, with the establishment of the end thermodynamic protection barrier, the system synchronously executes step S2 to activate the cold phase solidification and mechanical waste discharge path, providing a discharge channel that meets the material rheological requirements for the high-temperature solid waste generated by the subsequent central support point 103. During the continuous operation of the vacuum coating equipment, the detached cadmium telluride debris usually carries heat exceeding 300 degrees Celsius. If it is directly introduced into a room temperature or uncontrolled closed pipe, the debris will cross the material's plastic deformation critical point when it is piled up and compressed, resulting in interface fusion, i.e., hot-pressing sintering. To solve the technical problem that high-temperature dust easily agglomerates and jams the conveying mechanism in a non-airflow environment, this step activates the circulating cooling jacket covering the stainless steel conveying pipe at the waste receiving end and sets the rotation speed of the internal shaftless mechanical screw conveyor to 5 revolutions per minute. The essence of this operating logic is to pre-set a low-temperature physical baseline with heat exchange rate in space and use the heat conduction of the pipe wall to reduce the temperature of the high-temperature material 106. The set low rotation speed prolongs the residence and heat exchange time of material 106 in the cooling zone, ensuring that its temperature has dropped to the conditions required for internal lattice recombination before being subjected to mechanical pushing force. Implementing this step alters the macroscopic rheological properties of the cadmium telluride waste, allowing it to maintain a dry and loose granular morphology during the pushing and waste discharge cycle. This prevents the solid material 106 from forming hard lumps in the pipeline, providing a stable physical channel for the continuous discharge of subsequent waste and reducing downtime caused by forced disruption of the main cavity vacuum for cleaning due to blockage of the sewage pipe.

[0035] Step S3: Perform thermodynamic compensation and stress-induced peeling: Monitor system resistance and induce thermal stress at the interface of heterogeneous materials through transient thermal pulses to induce microcracks in the solid attachments.

[0036] Specifically, after the end protection and bottom waste discharge paths are in operation, the system performs thermodynamic compensation and stress-induced peeling by executing step S3 to address the solid deposits formed at the intermediate support point 103 of the ceramic roller 104 due to long-term bearing of the substrate's weight. Because the deposits at the support point are highly hard, direct mechanical cutting could easily cause fluctuations in resistance torque and damage the ceramic roller 104 substrate. Therefore, this step employs a physical intervention strategy of force-thermal coupling. The control system monitors the operating current of the drive motor in real time. When a current pulsation exceeds 10% of the reference value, it is determined that deposits affecting glass transport have formed at the support point. At this time, the internal heating core 108 outputs a transient thermal pulse within three seconds, raising the local temperature from the base of 350 degrees Celsius to 410 degrees Celsius. The physical logic of this operation is based on the difference in the thermal expansion coefficients of the heterogeneous materials. The 150-micron-thick anisotropic thermal expansion transition layer 110 of silicon nitride on the surface of the ceramic roller 104, the internal ceramic substrate, and the externally condensed cadmium telluride crystals undergo asynchronous volume expansion upon heating, with the difference in their volume expansion rates exceeding two parts per million per Kelvin. This mismatch in microscopic deformation translates into macroscopic shear thermal stress at the material interface, with a calculated value reaching 40 MPa. This approach solves the problem of mechanical fatigue and substrate wear easily caused by simple mechanical scraping. The interfacial shear thermal stress of 40 MPa exceeds the fracture modulus of cadmium telluride crystals, causing the dense solid deposits to crack and resulting in penetrating microcracks in their internal network. The beneficial effect of this step is that it reduces the mechanical bonding strength of the deposits by more than 80%, transforming heavy cutting into a low-load physical peeling pretreatment, and protecting the ceramic roller 104 substrate from excessive cutting stress.

[0037] Step S4, In-situ dynamic cutting and adaptive scraping: The constant positive pressure of the adaptive mechanical scraping plate 112 and the rotational shearing force of the high-temperature ceramic roller 104 used for transmission are used to cut away the solid deposits that have generated microcracks.

[0038] Specifically, after thermal stress induces microcracks in the adhered material, step S4 performs in-situ dynamic cutting and adaptive scraping, using mechanical force to complete the final removal of the waste. The technical challenge of this step is how to limit frictional resistance while ensuring effective scraping, preventing the drive motor from stalling due to excessive cutting torque. The system uses a nickel-based disc-shaped high-temperature spring 113 to apply normal force to the scraper plate 112 coated with titanium-aluminum nitride. The calculation logic is based on Hooke's Law, where the normal force equals the product of the spring constant and the preload compression. Under 350 degrees Celsius conditions, with a known spring constant of 2500 Newtons per meter and an assembly preload compression set at 0.012 meters, the calculated unilateral normal force is 30 Newtons. The logic behind this pressure value is to provide the shear force required to cut the microcrack connections while keeping it below the compressive strength limit of the ceramic substrate. Subsequently, system dynamics were calculated using the frictional resistance torque formula. The total frictional resistance torque is equal to the product of the dynamic friction coefficient generated by the two scraping plates 112, the normal force, and the radial radius of the support point of the ceramic roller 104. Substituting the dynamic friction coefficient of 0.25, the normal force of 30 Newtons, and the radial radius of 0.04 meters, the resistance torque added to a single ceramic roller 104 by the scraping action was calculated to be 0.6 Newton-meters. Compared to the maximum redundant torque of 15 Newton-meters set for the main drive motor, the frictional load of 0.6 Newton-meters only occupies four percent of the motor's margin. This torque distribution logic solves the hidden danger of the cleaning device interfering with the main production drive, ensuring the uniform and stable transmission of the glass substrate 102 while stripping waste, and reducing equipment vibration caused by sudden load changes.

[0039] Step S5, Gravity diversion and anti-sintering conveying of solid waste: The detached debris with high enthalpy is introduced into the stainless steel conveying pipe and forced heat exchange is carried out during the physical pushing process to achieve cold phase solidification.

[0040] Specifically, the loose solid waste, after being cut and stripped as described above, falls into the aforementioned sewage discharge channel under gravity. The system then executes step S5 to guide the solid waste by gravity and prevent sintering. In the low-pressure vacuum where airflow is lacking as a transport medium, the transfer of waste relies on the pure physical pushing of the shaftless mechanical screw conveyor. Solving the problem of material 106 accumulation and overflow requires calculating the mechanical displacement of the equipment. The calculation logic of the mass conveying rate is to convert the effective volumetric displacement of the screw into the mass flow per unit time. The formula is expressed as a constant of sixty multiplied by a quarter of pi, multiplied by the difference between the square of the outer diameter and the square of the inner diameter of the screw, and then multiplied by the screw pitch, motor speed, loose powder density, material 106 filling coefficient, and inclined arrangement coefficient. Given that the shaftless auger has an outer diameter of 0.06 meters, an inner diameter of zero, a pitch of 0.05 meters, a servo motor speed of 5 revolutions per minute, and a bulk density of 3500 kg / m³ for the cold-cured cadmium telluride powder, and considering the irregular shape of the debris, a filling coefficient of 0.15 is taken, and a horizontal arrangement tilt coefficient of 1.0, these engineering data are substituted into the formula to calculate that the theoretical mass conveying capacity of the conveying system reaches 22.27 kg / hour. Since the actual solid contaminant generated per hour by a single ceramic roller 104 support point is between 0.005 and 0.015 kg, this calculation logic reflects that the system has discharge redundancy. The significance of this parameter setting is to ensure that the waste in the conveying pipeline is in a low-filling state, preventing local accumulation and high pressure. The beneficial effect of this step is that it realizes the unidirectional discharge of solid waste in a vacuum environment. With the action of the end vacuum lock valve, the working state of the internal space of the main cavity is maintained, ensuring the continuous operation of the coating production line.

[0041] Step S6, Vacuum Locking and Closed-Loop Waste Discharge: Discharge the cooled and solidified solid waste without damaging the vacuum level of the main cavity 101 of the equipment coating.

[0042] Specifically, after the waste material is cooled and converted into loose particles through the conveying pipeline, the system enters step S6 to perform vacuum lock and closed-loop sludge removal. This step aims to resolve the physical conflict between the waste removal operation under normal pressure and the continuous high-vacuum production in the main chamber. Under normal operating conditions, removing the internal waste material usually requires stopping the machine and breaking the vacuum in the main chamber, which would disrupt the thermal balance and production cycle of the sublimation coating. Therefore, this step relies on dual vacuum valves for airtight isolation and timing switching. When the cadmium telluride waste collected in the 0.05 cubic meter vacuum lock dust collection tank reaches the set level, the system first closes the top gate valve, cutting off the physical channel between the dust collection tank and the main chamber, which maintains a vacuum of 0.5 Pa. Then, protective gas is introduced into the tank until the internal pressure reaches the standard atmospheric pressure of 1.01 x 10⁵ Pa, and then the bottom discharge valve is opened to discharge the loose waste material. After evacuation and closing the bottom valve, the system starts the auxiliary vacuum pump to independently evacuate the dust collection tank. The control logic at this stage employs a vacuum pumping time equation, where the pumping time equals the container volume divided by the pump's effective pumping speed, multiplied by the natural logarithm of the ratio of initial pressure to target pressure. This calculation logic is used to precisely define the control system's action delay parameters, preventing accidental opening of the top valve before the pressure differential is eliminated, which could cause backflow and disrupt the film-forming environment. Using specific engineering data—a dust collection tank volume of 0.05 cubic meters, an auxiliary pump's effective pumping speed of 0.02 cubic meters per second, an initial pressure of 1.01 x 10⁵ Pa, and a target pressure of 0.5 Pa—the natural logarithm of the pressure ratio is calculated to be approximately 12.2, and the required pumping recovery time is approximately 30.5 seconds. This quantitative timing setting solves the pressure backflow interference problem during the discharge process, ensuring that the top valve is only reopened to receive the next batch of material 106 after the dust collection tank pressure has fully recovered to 0.5 Pa. This step, without disturbing the low air pressure and temperature gradient of the main coating chamber, constructs an airlock drainage channel independent of the main production line, physically decoupling the intermittent waste discharge action from the continuous coating production, and maintaining the continuous operation cycle of the equipment.

[0043] Example 2 Please see Figures 1-5 As shown, this embodiment is a further optimization based on embodiment one. In this embodiment, the implementation details of the stator-side thermodynamic anti-sublimation shielding ring 109 component and the micro-dynamic mechanism of its execution step S1 are described in detail.

[0044] The stator-side thermodynamic anti-sublimation shielding ring 109 assembly includes a stator-side thermodynamic anti-sublimation shielding ring 109 rigidly anchored to the fixed bracket 105. This shielding ring is sintered from alumina ceramic and is fitted onto the outer end of the continuously rotating high-temperature ceramic roller 104, forming a non-contact radial micro-gap with the wall surface of the high-temperature ceramic roller 104. The inner surface of the shielding ring is machined with a labyrinthine annular groove with multiple trapezoidal cross-sections. A resistance heating element and a temperature sensor are embedded inside the shielding ring. The system also includes a control system connected to the resistance heating element and the temperature sensor.

[0045] During step S1, the control system maintains the surface temperature of the stator-side thermodynamic anti-sublimation shielding ring 109 within the temperature range of 450°C to 500°C. Cadmium telluride molecules entering the radial micro-gap absorb thermal radiation upon diffuse reflection collisions with the labyrinthine annular toothed grooves of multi-level trapezoidal cross-sections. According to Knudsen's gas molecular dynamics principles, the net sublimation flux formula for the solid surface is as follows:

[0046] This mathematical expression aims to quantify the mass exchange rate between a solid surface and the gas phase under extreme low-pressure vacuum conditions. The setting of its calculation process is the theoretical basis for solving the problem of gaseous pollutant permeation.

[0047] The definitions of each character in the formula are as follows: Net sublimation flux on the surface of the shielding ring within the micro-gap, in units of It is used to characterize the mass of matter transferred per unit area per unit time; The evaporation coefficient of cadmium telluride is dimensionless and reflects the influence of the microstructure of the material surface on the probability of molecules breaking free from their bonds. The saturated vapor pressure of cadmium telluride at a given absolute surface temperature, expressed in units of... ; The actual local vacuum partial pressure within the main cavity 101 of the equipment for coating, in units of... ; The molar mass of cadmium telluride, in units of ; Ideal gas constant, with a value of 8.314. ; : Absolute surface temperature of the stator-side thermodynamic anti-sublimation shielding ring 109, in units of .

[0048] This square root term originates from the Maxwell-Boltzmann rate distribution law, representing the average thermal velocity of gas molecules. The logic behind this calculation is that when the system is in a high vacuum state where the mechanical properties of the continuum fail, the fluid pressure difference barrier is no longer applicable, and the direction of the molecular phase transition must be changed by controlling the temperature difference.

[0049] Specific application scenario analysis: In a vacuum sublimation coating production line for cadmium telluride photovoltaic glass with a width of 1200mm × 600mm, the steady-state local vacuum partial pressure of the main coating chamber 101 during normal operation is as follows: The absolute temperature of the shielding ring surface is 0.5 Pa. It is locked at 673.15 K (i.e., 400 °C). At this temperature, the saturated vapor pressure of cadmium telluride is... The pressure is 1.8 Pa. The evaporation coefficient of cadmium telluride is known. Take 0.45, its molar mass It is 0.24 kg / mol.

[0050] Substitute the above data into the sublimation flux formula:

[0051] The pressure difference term of the molecular part is calculated to obtain... Taking the square root of the thermal motion term in the denominator yields approximately The net sublimation flux was ultimately obtained. .

[0052] The physical significance of this calculation result is that, A positive value indicates that the transformation from the solid phase to the gas phase is dominant. The calculation process involves setting... The boundary conditions establish a kinetic energy repulsion field within the non-contact radial micro-gap. Free cadmium telluride molecules entering the gap are forced into a gaseous state by this sublimation potential energy upon colliding with the heated labyrinthine tooth groove wall and ejected in the opposite direction. This calculation logic not only provides a quantitative basis for setting the target of the temperature control system, but also solves the common industry problem of conventional mechanical contact seals being prone to wear and unable to prevent Knudsen diffusion. Through precise calculation of the thermodynamic state, the path for solid deposits to form inside the bearing is cut off at the source without increasing the mechanical friction load, ensuring the long-term operation of the transmission system.

[0053] Example 3 like Figures 1-5 As shown, this embodiment details the construction of the differential thermal expansion induced peeling and adaptive scraping component, as well as the force-thermal coupling response mechanism for executing steps S3 and S4.

[0054] The intermediate support point 103 of the high-temperature ceramic roller 104 for transmission is coated with a micron-scale anisotropic thermal expansion transition layer 110 (made of silicon nitride thin film). The thermal expansion coefficient of this transition layer 110 is different from that of the substrate of the high-temperature ceramic roller 104 for transmission, and also different from that of condensed cadmium telluride. A heating core 108 is provided inside the high-temperature ceramic roller 104 for transmission. A clamp base is fixed below the support point 103, and the clamp base is pivotally connected to a pair of adaptive mechanical scraping plates 112 coated with a high-temperature wear-resistant titanium aluminum nitride coating. The adaptive mechanical scraping plates 112 apply a constant normal force to the support point 103 through a nickel-based disc-shaped high-temperature spring 113.

[0055] During step S3, the control system monitors the operating current of the motor driving the high-temperature ceramic roller 104 for transmission in real time. When the current pulsation exceeds a set reference value and reaches a threshold range, the control system outputs a high-level pulse, i.e., a transient thermal pulse, to the heating core 108 inside the high-temperature ceramic roller 104 for transmission. The difference in expansion between the micron-level anisotropic thermal expansion transition layer 110, the substrate, and the cadmium telluride deposit after heating generates interfacial shear thermal stress, thereby cracking the solid deposit and creating microcracks.

[0056] During step S4, the adaptive mechanical scraper 112, through normal pressure and the rotational shearing force of the high-temperature ceramic roller 104, cuts away the solid deposits with microcracks. The formulas for the mechanical normal pressure and frictional resistance torque in this process are as follows:

[0057] This calculation process is designed to ensure cutting effectiveness while limiting mechanical resistance within the redundant load range of the drive motor.

[0058] The definitions of each character in the formula are as follows: The constant normal force applied by a single-sided nickel-based disc high-temperature spring 113, in units of ; The spring constant of the nickel-based disc high-temperature spring 113 at a set temperature, in units of... ; The preload compression of the nickel-based disc high-temperature spring 113, in units of... .

[0059]

[0060] The definitions of each character in the formula are as follows: The total frictional resistance torque applied by the two adaptive mechanical scraper blades 112 to the single high-temperature ceramic conveying roller 104 is expressed in units of... ; : Dynamic friction coefficient of the mixed surface of titanium aluminum nitride high-temperature wear-resistant coating and ceramic roller 104, dimensionless; : Unilateral constant normal force, unit is ; : The radial radius of the intermediate support point 103 of the high-temperature ceramic roller 104 for transmission, in units of ; Number 2: indicates a pair (two) adaptive mechanical scraper blades 112.

[0061] In the formula for frictional resistance torque, The total rotational resistance torque (in units) applied to the single high-temperature ceramic roller 104 for conveying by the two adaptive mechanical scraper blades 112. ),constant This represents the number of opposing scraper blades 112. The dynamic friction coefficient (dimensionless) is the surface of a mixture of titanium nitride aluminum high-temperature wear-resistant coating and cadmium telluride and ceramic substrate with microcracks. That is the radial rotation radius of the intermediate support point 103 (unit: ). This computational architecture is adopted because the uniform transmission of the glass substrate 102 during coating is extremely sensitive to torque fluctuations, and the deposits cannot be damaged by blindly increasing the hardness of the scraper.

[0062] Specific application scenario analysis: In the aforementioned production line, the radial radius of the intermediate support point 103 of the high-temperature ceramic roller 104 for conveying... The length is 0.04m, and the maximum redundant torque set for the main drive motor is 15. The heating core 108 is maintained at a base temperature of 350°C. When the motor current pulsation exceeds the reference value by 10%, the heating core 108 outputs a transient thermal pulse, causing the local temperature to rise to 410°C. The difference in the volumetric expansion rate between the anisotropic thermal expansion transition layer 110 and cadmium telluride induces interfacial shear thermal stress, causing microcracks to form in the deposited material.

[0063] The spring constant of nickel-based disc spring 113 at 350℃ is known. The preload compression is 2500 N / m. It is 0.012m. Substituting into the normal force formula:

[0064] Determination of the dynamic friction coefficient between titanium nitride aluminum high-temperature wear-resistant coating and surface The value is 0.25. Substituting this into the frictional resistance torque formula:

[0065] The calculated total frictional resistance torque is 0.6. 15% of the drive motor 4% of the maximum redundant torque. This value satisfies the mechanical load requirements for continuous transmission of the system while cutting away solid deposits that generate microcracks.

[0066] This calculation process resolves the technical hazard of potential stalling of the main drive system caused by the online cleaning device. This is achieved by using the maximum rated redundant torque set with the main drive motor. By comparison, the calculated results Frictional load only accounts for a portion of the total system redundancy. This rigorous dynamics simulation theoretically verifies the safety of the flexible bonding scraping scheme, explaining why the system can perform in-situ dynamic cutting without stopping the machine. It transforms destructive hard grinding into smooth peeling under controlled boundaries, effectively removing hard deposits and ensuring the stability of substrate transmission while avoiding tool breakage and motor overload.

[0067] Example 4 like Figures 1-5 As shown, this embodiment details the structural system of the solid pollutant cold phase solidification and airless mechanical collection component, as well as the control principles of execution steps S2, S5, and S6.

[0068] The solid pollutant cold-phase solidification and airless mechanical collection assembly is arranged directly below the adaptive mechanical scraper 112, and includes an inverted conical gravity guide receiving groove and a horizontal stainless steel conveying pipe connected to its bottom. A shaftless mechanical spiral conveying rod driven by an external servo motor passes through the interior of the stainless steel conveying pipe, and the exterior of the stainless steel conveying pipe is covered with an independent circulating cooling jacket. The end of the stainless steel conveying pipe is connected to a vacuum-locked dust collection tank with dual vacuum valves, including a top baffle valve and a bottom discharge valve.

[0069] When performing step S2, the external servo motor is started to make the shaftless mechanical screw conveyor rotate, and the circulating cooling jacket is turned on.

[0070] During step S5, the cut-off high-temperature solid debris falls into the stainless steel conveying pipe under gravity. As the shaftless mechanical screw conveyor pushes the material 106 forward, the circulating cooling jacket forcibly cools the high-temperature material 106 inside the pipe. This alters the rheological properties of the solid debris, maintaining it in a loose granular state and preventing thermal sintering during mechanical extrusion. The mass conveying rate formula is as follows:

[0071] The definitions of each character in the formula are as follows: The mass conveying rate of a mechanical screw conveyor system, in units of ; The outer diameter of a shaftless mechanical screw conveyor, in units of... ; The inner diameter of the shaftless mechanical screw conveyor is 0 for shaftless structures. ; The pitch of a shaftless mechanical screw conveyor, in units of... ; The speed of the external servo motor, in units of ; The bulk density of the cooled and solidified cadmium telluride solid waste, in units of... ; Material 106 filling coefficient, dimensionless; : Correction factor for inclined arrangement of conveying pipe, with a value of 1.0 for horizontal arrangement, dimensionless.

[0072] constant 60 and Used for time unit conversion and cross-sectional area calculation.

[0073] This long-chain multiplication expression encompasses all the geometric and physical property variables of the Archimedes screw conveyor and is designed to calculate the actual physical displacement in a non-airflow environment.

[0074] This calculation process is designed to address the problem of gas-carrying power loss in a vacuum environment, requiring the replacement of aerodynamic suction with purely mechanical volumetric displacement.

[0075] This calculation process, by quantifying waste removal capacity, directly guides the setting of the transmission ratio and operating logic. In actual production, the solid debris generated per hour by a single ceramic roller (104) is only... to Between. The huge displacement redundancy proves that only the following approach is needed. Extremely low rotational speeds are sufficient to meet sewage discharge requirements. The physical purpose of this low-speed setting is to increase the residence time of the high-temperature powder within the stainless steel conveying pipe, allowing for sufficient solid-wall heat exchange with the external circulating cooling jacket. Calculations have verified that the system operates under low load conditions, avoiding heat accumulation caused by high-speed extrusion. From a material rheological perspective, this prevents the high-temperature cadmium telluride powder from undergoing thermo-pressurization sintering and hardening inside the pipe, ensuring the smooth operation of the entire online sewage discharge pipeline and the reliable execution of the vacuum lock action during long-term operation.

[0076] When performing step S6, the system sequentially closes the top gate valve, fills the vacuum lock dust collection tank with gas to break the vacuum, opens the bottom discharge valve to discharge the cooled and solidified solid waste, then closes the bottom discharge valve, re-vacuums, and opens the top gate valve to complete the closed-loop sewage discharge.

[0077] To ensure the reliability of closed-loop control and prevent backflow caused by accidental opening of the top gate valve before the pressure difference is eliminated, the control system incorporates a vacuum pumping time control algorithm model. The pumping recovery delay time is calculated in real time using the following formula:

[0078] The definitions of each character in the formula are as follows: : Vacuum recovery delay time, in units of ; The effective volume of the vacuum lock dust collection tank, in units of... ; The effective pumping speed of the auxiliary vacuum pump, in units of... ; : Initial atmospheric pressure inside the chamber when the bottom discharge valve is closed after discharge is completed, in units of ; The target local vacuum partial pressure of the main cavity 101 of the equipment for coating, in units of... .

[0079] The system calculates the delay time using this model. Then, the opening command of the top gate valve is executed, achieving precise decoupling of the physical airlock. Specific application scenario analysis: In the aforementioned production line, the external servo motor speed Set to 5 r / min. Outer diameter of the shaftless mechanical screw conveyor. It is 0.06m, inner diameter 0m, pitch The inclination coefficient for horizontal arrangement is 0.05m. Take 1.0. Loose density of cadmium telluride powder after cold phase curing. The material has a fill factor of 106 and a density of 3500 kg / m³. Set to 0.15.

[0080] Substitute the above data into the mass delivery rate formula:

[0081] The system's mass delivery rate was calculated to be... The conveying capacity is 22.27 kg / h. Since the amount of solid contaminants accumulated per hour at the support point of a single high-temperature ceramic roller 104 for conveying is typically between 0.005 kg / h and 0.015 kg / h, this 22.27 kg / h conveying rate meets the process requirements for continuously and unidirectionally removing the falling solid waste from the main coating cavity 101 of the equipment. Combined with the dual vacuum valve timing control in step S6, an online self-cleaning closed-loop system is achieved during equipment operation.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An online self-cleaning and anti-fouling system for a cadmium telluride power generation glass vacuum coating ceramic roller, comprising: Multiple high-temperature ceramic rollers for conveying glass substrates are arranged in parallel along the conveying direction. Each high-temperature ceramic roller is mounted at both ends to fixed supports on both sides of the main coating cavity of the equipment via bearings. The characteristic of this invention is that... The system also includes three synergistic components: thermodynamic and mechanical dynamic closed-loop coupled feedback. Stator-side thermodynamic anti-sublimation shielding ring assembly disposed between the fixed bracket and the end of the high-temperature ceramic roller for transmission; A differential thermal expansion-induced peeling and adaptive scraping assembly is disposed at the intermediate support point of the high-temperature ceramic roller for transmission; and Solid contaminant cold phase solidification and airless mechanical collection assembly is located below the differential thermal expansion induced peeling and adaptive scraping assembly.

2. The online self-cleaning and anti-fouling system for cadmium telluride photovoltaic glass vacuum coating ceramic roller according to claim 1, characterized in that, The stator-side thermodynamic anti-sublimation shielding ring assembly includes: A stator-side thermodynamic anti-sublimation shielding ring is rigidly anchored to the fixed bracket. The shielding ring is sleeved on the outer side of the end of the continuously rotating high-temperature ceramic roller for transmission and forms a non-contact radial micro-gap with the wall surface of the high-temperature ceramic roller for transmission. The inner surface of the shielding ring is machined with a labyrinthine annular toothed groove with a multi-stage trapezoidal cross section. A resistance heating element and a temperature sensor are embedded inside the shielding ring.

3. The online self-cleaning and anti-contamination system for a cadmium telluride power generation glass vacuum coating ceramic roller according to claim 2, characterized in that, The system also includes a control system connected to the resistive heating element and the temperature sensor. The surface temperature of the stator-side thermodynamic anti-sublimation shielding ring is maintained by the control system in a high-temperature range of 450°C to 500°C to construct a gas-solid phase change reverse gradient blocking mechanism within the radial micro-gap.

4. The online self-cleaning and anti-fouling system for cadmium telluride photovoltaic glass vacuum coating ceramic roller according to claim 1, characterized in that, The intermediate support site of the high-temperature ceramic roller for transmission is coated with a micron-scale anisotropic thermal expansion transition layer. The thermal expansion coefficient of this transition layer is different from that of the substrate of the high-temperature ceramic roller for transmission and also different from that of condensed cadmium telluride. The high-temperature ceramic roller for transmission is equipped with a heating core inside. The heating core is used to output a transient thermal pulse to the support site when abnormal rotational resistance is detected. The interfacial shear thermal stress between the heterogeneous materials induces microcracks in the solid deposits.

5. The online self-cleaning and anti-fouling system for a cadmium telluride power generation glass vacuum coating ceramic roller according to claim 4, characterized in that, The differential thermal expansion induced peeling and adaptive scraping assembly also includes: A clamp base is fixed below the support point, and the clamp base is pivotally connected to a pair of adaptive mechanical scraping plates coated with a high-temperature wear-resistant titanium aluminum nitride coating; the adaptive mechanical scraping plates apply a constant normal force to the support point through a nickel-based disc-shaped high-temperature spring, so as to cut away the solid attachment with microcracks through rotational shear force.

6. The online self-cleaning and anti-fouling system for cadmium telluride photovoltaic glass vacuum coating ceramic roller according to claim 5, characterized in that, The solid pollutant cold phase solidification and airless mechanical collection assembly is arranged directly below the adaptive mechanical scraper, including an inverted conical gravity guide receiving groove and a horizontal stainless steel conveying pipe connected to its bottom; the inside of the stainless steel conveying pipe is equipped with a shaftless mechanical spiral conveying rod driven by an external servo motor, and the outside of the stainless steel conveying pipe is covered with an independent circulating cooling jacket.

7. The online self-cleaning and anti-fouling system for a cadmium telluride power generation glass vacuum coating ceramic roller according to claim 6, characterized in that, The end of the stainless steel conveying pipe is connected to a vacuum lock dust collection tank with dual vacuum valves. The dual vacuum valves include a top slide valve and a bottom discharge valve, which are used to discharge the cooled and solidified solid waste while maintaining the vacuum level of the main cavity of the equipment coating.

8. A method for online self-cleaning and anti-contamination of a cadmium telluride power generation glass vacuum coating ceramic roller, characterized in that, The system applied to any one of claims 1 to 7 includes the following steps: A reverse gradient blocking thermodynamic field is established to construct a non-contact thermal radiation labyrinth field between a stationary fixed support and the end of a rotating high-temperature ceramic roller for transmission. Activate the cold phase solidification and mechanical waste discharge path, and start the bottom airless mechanical collection component and circulating cooling jacket; Thermodynamic compensation and stress-induced delamination are performed, system resistance is monitored, and thermal stress is induced at the interface of heterogeneous materials by transient thermal pulses, causing microcracks to be generated in the solid attachments. In-situ dynamic cutting and adaptive scraping utilize the constant positive pressure of the adaptive mechanical scraping plate and the rotating shearing force of the high-temperature ceramic roller for transmission to cut away solid deposits with microcracks. Gravity-guided and anti-sintering conveying of solid waste introduces detached debris with high enthalpy into a stainless steel conveying pipe and performs forced heat exchange cooling during the physical pushing process to achieve cold phase solidification. Vacuum lock and closed-loop sewage discharge allow for the discharge of cooled and solidified solid waste without compromising the vacuum level of the main cavity of the equipment's coating process.

9. The method for online self-cleaning and anti-contamination of a cadmium telluride photovoltaic glass vacuum coating ceramic roller according to claim 8, characterized in that, The specific execution logic for performing thermodynamic compensation and stress-induced delamination, monitoring system resistance, and inducing thermal stress at the interface of heterogeneous materials through transient thermal pulses to generate microcracks in the solid attachment includes: The operating current of the motor driving the high-temperature ceramic roller for transmission is monitored in real time. When the current pulsation exceeds the set reference value and reaches the threshold range, a high-level pulse is output to the heating core inside the high-temperature ceramic roller for transmission. Stress is generated by the difference in the amount of expansion of the micron-level anisotropic thermal expansion transition layer, the substrate and the cadmium telluride deposit after heating, thereby cracking the solid deposit to complete the pretreatment for peeling.

10. The method for online self-cleaning and anti-contamination of a cadmium telluride photovoltaic glass vacuum coating ceramic roller according to claim 9, characterized in that, The gravity-guided and anti-sintering conveying of the solid waste involves guiding the detached debris with high enthalpy into a stainless steel conveying pipe and subjecting it to forced heat exchange and cooling during the physical pushing process to achieve cold phase solidification. The specific execution logic includes: After being cut off, the high-temperature solid debris falls into the stainless steel conveying pipe under the action of gravity. During the process of the shaftless mechanical screw conveyor pushing the material forward, the circulating cooling jacket forces the high-temperature material in the pipe to cool down, changing the rheological properties of the solid debris to keep it in a loose particle state, thereby preventing the solid debris from undergoing hot pressing sintering during mechanical extrusion.

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