WO2010107293A1 - System and method for forming and tempering glass panels with radio frequency energy - Google Patents

System and method for forming and tempering glass panels with radio frequency energy Download PDF

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Publication number
WO2010107293A1
WO2010107293A1 PCT/MX2010/000022 MX2010000022W WO2010107293A1 WO 2010107293 A1 WO2010107293 A1 WO 2010107293A1 MX 2010000022 W MX2010000022 W MX 2010000022W WO 2010107293 A1 WO2010107293 A1 WO 2010107293A1
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WIPO (PCT)
Prior art keywords
glass
forming
radio frequency
temperature
glass sheet
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PCT/MX2010/000022
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Spanish (es)
French (fr)
Inventor
Premakaran T. Boaz
Alfredo MARTÍNEZ-SOTO
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Vitro Corporativo, Sa De Cv
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Publication of WO2010107293A1 publication Critical patent/WO2010107293A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B27/00—Tempering or quenching glass products
    • C03B27/012—Tempering or quenching glass products by heat treatment, e.g. for crystallisation; Heat treatment of glass products before tempering by cooling
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B29/00—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins
    • C03B29/04—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way
    • C03B29/06—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way with horizontal displacement of the products
    • C03B29/08—Glass sheets

Definitions

  • the present invention relates generally to glass tempering and more particularly to a system and method for forming and tempering glass panels with radio frequency energy. DESCRIPTION OF RELATED ART.
  • Tempered or heat treated glass is generally defined as glass (for example annealed or ordinary) that has been pre-fatigued when heated to a temperature substantially or above the softening point of the glass and being forced to suddenly and quickly quench in controlled conditions of care.
  • the tempering process produces tempered glass that has high desirable conditions of induced stress resulting in additional strength, resistance to thermal stress and impact resistance when compared to ordinary or annealed glass.
  • the basic principle used in the tempering process is to create an initial compression condition of the edge and surface of the glass. This condition is carried out by first calendaring the glass and then cooling the glass surface quickly. Said heating and cooling leaves the thickness of the center of the glass relatively hot in relation to the surface of the glass. When the thickness of the center cools, the surfaces are forced to a compression effect. Wind pressure, weapon impact, thermal stress or other loads applied They must first overcome this compression before any chance of glass breakage.
  • an oven is an oven which can be of the type of continuous rollers, of the type of fixed rollers or gas type.
  • a gas type furnace has a plurality of blocks arranged under a plurality of radiant heaters.
  • a sheet of glass is placed inside the oven where the sheet is heated by conventional radiation, convection and heat conduction.
  • the glass sheet moves along the blocks at a predetermined rate, which depends on the thickness and thermal conductivity of the glass sheet, to reach the temperature in the range of the glass sheet.
  • said temperature for example approximately 1200 degrees F
  • the glass sheet is formed to a predetermined shape.
  • the glass sheet is quickly tempered by air, typically by the application of an air flow to the glass sheet.
  • the air flow may consist of fixed, rotary or reciprocating nozzle arrangements. It is important to extract the heat uniformly from both surfaces of the glass (the irregular extraction of heat can produce arches or combas) and to sustain cooling long enough to prevent overheating of the glass surface of the center, still hot of the sheet of glass.
  • the cooling condition begins to be stable when the temperature of the glass sheet is reduced by approximately 400 degrees C.
  • the oven described above works well, it has the disadvantage that the oven must be long enough to allow the glass sheet to be heated at a predetermined rate.
  • the oven length requires a large amount of floor space, energy consumption and costs.
  • a recent approach to overcome this disadvantage is to use microwave energy [at frequencies in the range of 2 gigahertz (GHz) to 40 GHz] to quickly and efficiently heat the glass sheet that has been pre-heated to a temperature substantially at or by above the softening temperature through conventional means.
  • microwave energy at frequencies in the range of 2 gigahertz (GHz) to 40 GHz
  • U.S. Patent No. 5,782,947 to Boaz describes a method of heating a glass sheet including the steps of heating the glass sheet at a first predetermined temperature and applying microwave energy to the glass sheet to heat it to the at least a second temperature. predetermined to allow the glass sheet to be formed.
  • An advantage of the method described in US Patent No. 5,782,947 assigned to Boaz, is that the length of the furnace is reduced, which results in a lower floor space and increase (speed and production) of the glass sheet being formed .
  • U.S. Patent No. 5,827,345 to Boaz describes a method for heating, forming and tempering a glass sheet that includes the steps of heating the glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat it to at least a second predetermined temperature, forming the glass sheet to a predetermined configuration and cooling at least an external surface of the glass sheet at at least a third predetermined temperature to temper the glass sheet.
  • An advantage of the method described in US Patent No. 5,827,345 assigned to Boaz is that a relatively thin glass sheet can be tempered (for example less than 0.125 inches in thickness). More specifically, while the center of the glass sheet is being heated by microwave energy, the outer surface of the glass sheet is cooling, which creates a desired temperature gradient or differential between the center and the outer surface. of the glass sheet.
  • 6826929 and 7367205 assigned to Boaz which comprise applying radiofrequency energy with a frequency in a range of about 0.1 GHz to about 2.0 GHz from at least a hollow electrode to the glass sheet to heat the glass sheet to at least a second predetermined temperature, and to apply at least one air flow through at least one hollow electrode of at least one outer surface of the glass sheet to cool at least one outer surface of the glass sheet to at least a third predetermined temperature to temper the glass sheet.
  • the present invention is related to a new process for forming and / or tempering glass panels by means of which the glass is pre-heated in a conventional oven at a temperature that allows the glass to be transferred or formed. It is then transferred to a convenient temperature below the softening temperature of 660 degrees C. At this low temperature, around 650 degrees the glass is flexible enough to be formed, but rigid enough to resist distortion in normal transfer handling. .
  • This relatively cold glass at about 640 degrees C, (preferably between 620 and 65O 0 C) is then to an oven RW Inside the RW oven, the glass is heated to 66O 0 C for a cooling action. Since the inside of the oven
  • RW is at room temperature, it also houses the cooling system and the cooling takes place inside the chamber before the glass loses any temperature. This represents a great difference with respect to the conventional thermal tempering process.
  • Another advantage of the present invention is to provide a system and method, which is particularly useful for tempering thin glass of less than 3.0 mm thickness.
  • Figure 1 is a diagram of stages of a system and method for forming and tempering glass panels with radiofrequency energy according to the conventional tempering techniques of the prior art.
  • Figure 2 is a temperature graph for the tempering of glass sheets from a preheating phase to a cooling stage, in accordance with the conventional tempering techniques of the prior art.
  • Figure 3 shows a graph of data of the viscosity drop Ia soda lime glass in a temperature range of 550 ° C to 75O 0 C;
  • Figure 4 is a diagram of stages of a system and method for forming and tempering panels of high-frequency radio frequency energy, in accordance with the present invention.
  • Figure 5 is a temperature graph for tempering glass sheets from a preheating stage to a cooling stage according to the present invention.
  • Figure 6 is a first perspective view of the system for forming a sheet of tempered glass, in accordance with the present invention.
  • Figure 7 is a perspective view of the second mode of the system to form a sheet of tempered glass, in accordance with the present invention.
  • Figure 8 is a perspective view of a third embodiment of the system and method for forming and tempering glass panels. tempered with radio frequency energy, in accordance with the present invention. Y,
  • Figure 9 shows a photograph of the breaking pattern of a 3.00 mm glass together with the compression readings of the surface and the maximum particle size data.
  • Figures 10 to 13 are similar photographs of glass thicknesses up to 2.00 mm. DESCRIPTION OF THE PREFERRED MODES
  • FIG. 1 illustrates a sequence of the common tempering process and one of the physical difficulties that arise is that it requires a temperature rise up to 66O 0 C so that it can initiate the cooling operation.
  • the glass is heated in a conventional oven 1 and then transferred to a chamber 2, where it is formed (if necessary) and then a separation chamber 3 is transferred for the cooling operation.
  • the glass must be at a minimum of 66O 0 C so that tempering can be carried out.
  • the glass loses its temperature very quickly (up to 25 degrees / sec., In thin glass less than 3.0 mm thick) before the start of the cooling stage in the cooling station 3.
  • the conventional solution is to heat the last zone of the preheating furnace 4 (section 2 of Figure 2), up to approximately 700 0 C, and pass the glass through from this area at a fast speed. This makes use of the properties of the glass that during a rapid increase in the temperature of the glass, the viscosity of the glass goes behind.
  • Figure 2 shows the thermal history of the glass in more detail.
  • Section 1 shows the pre-heating portion of the glass preparation for the tempering operation.
  • Section 2 describes the additional increase in the temperature required in the preheating section to compensate for the loss of heat during the transfer to the cooling zone.
  • Section 3 indicates the current temperature loss of the glass panel prior to the start of cooling in Ia section 4.
  • Section 3 represents the transfer area in Figure 2, where the physical difficulties mentioned above reside.
  • the viscosity of the glass drops very quickly and the physical manipulation of the glass tends to impart optical distortions on the panel. This problem becomes even more serious when the panels are "thin" such as below 3.0 mm thick.
  • the cooling is normally carried out with forced air on the glass surface, extracting heat at a rapid rate to cool the outer surface T2 while the inner part T1 is still soft.
  • the greater cooling of the thermal contraction of the inner part creates a strong compression tension in the cooled outer surface while a tensile tension is induced in the inner part.
  • Figure 3 shows a graph of data of the drop in the viscosity of the limestone glass during the temperature range of our concern.
  • Figure 3 in the Log scale shows that the current viscosity falls by a factor of more than three between 630 and 660 0 C. It is this extreme drop in viscosity Ia that presents a serious processing problem when this soft glass has to be transported from the heating zone in the cooling zone without causing any optical distortion.
  • THE NEW PROCESS The new process consists of a unique way to form and / or temper glass panels.
  • Figure 4 describes the new process in which the glass is pre-heated in a conventional oven 5 to a temperature that allows the glass to be transferred or formed (6). This is then transferred at a convenient temperature below the softening temperature of 660 ° C.
  • the glass At a lower temperature of approximately 650 degrees C 1, the glass is flexible enough to be formed, but rigid enough to withstand the distortion of normal transfer handling.
  • This relatively cold glass of about 640 ° C, (preferably between 620 and 650 ° C) is then transferred to a radio frequency oven 7. Inside the radio frequency oven, the glass is heated to 660 ° C to that the cooling action be performed. Since the interior of the radio frequency oven 7 is at an ambient temperature, it also houses the cooling system and the cooling stage takes place inside the oven 7 before the glass decreases its temperature.
  • Figure 5 presents a detailed thermal history of the new process. Section 1A represents the preheating of the glass in a conventional oven. Section 2A shows the operation of forming the glass at about 650 0 C.
  • Section 3A shows the glass that is being heated to the cooling temperature of 660 0 C, by means of radio frequency energy. Radio frequency energy is preferably applied in about 20 Mega Hertz. At this frequency, the device is commercially available and has a proven safety record in the plant.
  • Section 4A shows the cooling operation within the same section 4A of Figure 4, where T1 represents the temperature of the inner surface and T2 represents the temperature of the outer surface. The cooling is which is normally carried out with forced air on the glass surface, for high speed extraction to cool the outer surface T2 while the inner part T1 is still soft. The cooling stage reduces the temperature of the treated glass sheet to a temperature within the range of about 415 ° C to 200 ° C.
  • Figure 6 shows a typical configuration of the electrodes within a radiofrequency chamber.
  • the two electrode beams of 10 and 11, the positive and the negative are placed near the glass sheet 13 and across the entire width of said glass sheet 13 to provide maximum exposure to the radiofrequency wave field that exists between The two terminals.
  • Air blowers 14 and 15 are provided above and below the glass to cool the glass 13, when the required temperature of 66O 0 is reached.
  • the time after which the heating stops and the cooling begins are controlled in fractions of a second
  • the glass rests on the rollers 16, which consists of ceramic rings 17 specially designed for the application of radio frequency.
  • the rings and rollers allow the free flow of air that is essential for the cooling process.
  • An additional modality of the process is described in Figure 7.
  • the glass at a convenient temperature of about 63O 0 C (between 620 and 65O 0 C) is transferred from the preheating section 5 to a set of rollers 16.
  • the rollers 16 are arranged in an arc representing a radius R, in which the formed and tempered glass intends to adhere. Normally, for example, some of the glass of the car door requires a radius of 30 ".
  • the radio frequency energy and the radio frequency wave are applied, as described above heats the glass at about 660 0 C. At this temperature the glass begins to "pande” in the arc of the rollers At the appropriate time, the cooling air is turned on to temper the panel.
  • An additional modality of this process is applicable to commercial glass for large windows of the "thick glass” category, generally in the range of 6.0 to 10.0 mm thick.
  • These glass panels present a unique problem to be tempered since a large temperature gradient is introduced along its length during the transfer of the preheating to the cooling chamber. The main initial end loses a large part of the temperature before the final end is outside the preheating oven. This gradient can be compensated by the increase in the preheating oven outlet temperature. However, this results in a distortion of the surface.
  • a uniform tempering can be introduced into the thick glass.
  • the electrodes of 11, 12 are placed to selectively heat the inlet portion of the glass at a rate greater than the rear.
  • the intensity of the radio frequency wave field that is applied to the glass This results in the front end of the glass receiving more radio frequency energy and its temperature approaching that of the end end. This also translates into energy savings in the preheating section in the process.
  • RW radio frequency tempering

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

Abstract

The invention relates to a method and system for forming and tempering panels of tempered glass using radio frequency. According to the invention, a glass sheet is pre-heated to at least a first pre-determined temperature equal to or below a glass sheet softening temperature. In addition, radio frequency energy is applied in order to heat the glass sheet to a temperature equal to or slightly below the pre-heated sheet softening temperature and the glass sheet is cooled in order to produce a tempered glass sheet.

Description

SISTEMA Y MÉTODO PARA EL FORMADO Y TEMPLADO DE PANELES DE VIDRIO CON ENERGÍA DE RADIOFRECUENCIA ANTECEDENTES DE LA INVENCIÓN CAMPO DE LA INVENCIÓN. La presente invención se relaciona generalmente al templado de vidrio y más particularmente a un sistema y método para el formado y templado de paneles de vidrio con energía de radio frecuencia. DESCRIPCIÓN DEL ARTE RELACIONADO. SYSTEM AND METHOD FOR THE FORMATION AND TEMPERATURE OF GLASS PANELS WITH RADIO FREQUENCY ENERGY BACKGROUND OF THE INVENTION FIELD OF THE INVENTION. The present invention relates generally to glass tempering and more particularly to a system and method for forming and tempering glass panels with radio frequency energy. DESCRIPTION OF RELATED ART.
El templado o vidrio tratado por calor se define generalmente como vidrio (por ejemplo recocido u ordinario) que ha sido pre-fatigado al ser calentado a una temperatura substancialmente o por encima del punto de ablandamiento del vidrio y siendo forzado para repentinamente y rápidamente templar en condiciones de cuidado controladas. El proceso de templado produce vidrio templado que tiene condiciones deseables altas de esfuerzo inducido que resulta en una fuerza adicional, resistencia al esfuerzo térmico y resistencia al impacto cuando se compara a un vidrio ordinario o recocido.Tempered or heat treated glass is generally defined as glass (for example annealed or ordinary) that has been pre-fatigued when heated to a temperature substantially or above the softening point of the glass and being forced to suddenly and quickly quench in controlled conditions of care. The tempering process produces tempered glass that has high desirable conditions of induced stress resulting in additional strength, resistance to thermal stress and impact resistance when compared to ordinary or annealed glass.
El. principio básico que se emplea en el proceso de templado es crear una condición inicial de compresión del borde y superficie del vidrio. Esta condición es llevada a cabo por primero calendar el vidrio y luego enfriar Ia superficie de vidrio rápidamente. Dicho calentamiento y enfriamiento deja el espesor del centro del vidrio relativamente caliente con relación a Ia superficie del vidrio. Cuando el espesor del centro se enfría, las superficies son forzadas a un efecto de compresión. La presión del viento, impacto de arma, esfuerzo térmico u otras cargas aplicadas deben primero superar esta compresión antes de cualquier posibilidad de fractura del vidrio.The basic principle used in the tempering process is to create an initial compression condition of the edge and surface of the glass. This condition is carried out by first calendaring the glass and then cooling the glass surface quickly. Said heating and cooling leaves the thickness of the center of the glass relatively hot in relation to the surface of the glass. When the thickness of the center cools, the surfaces are forced to a compression effect. Wind pressure, weapon impact, thermal stress or other loads applied They must first overcome this compression before any chance of glass breakage.
Con relación a Ia etapa de calentamiento, es bien conocido usar un hogar o horno para calendar las laminas de vidrio para ser templadas. Generalmente hablando, un horno es un horno el cual puede ser del tipo de rodillos continuos, del tipo de rodillos fijos o tipo gas. Por ejemplo, un horno de tipo gas tiene una pluralidad de bloques dispuestos debajo de una pluralidad de calentadores radiantes. Tradicionalmente, una lámina de vidrio es colocada dentro del horno en donde Ia lámina se calienta por radiación convencional, convección y conducción de calor. La lámina de vidrio se mueve a Io largo de Io bloques a una tasa predeterminada, el cual depende del espesor y de Ia conductividad térmica de Ia lámina de vidrio, para alcanzar Ia temperatura en el rango de formación de Ia lámina de vidrio. Cuando dicha temperatura es alcanzada (por ejemplo aproximadamente 1200 grados F), Ia lámina de vidrio es formada a una forma predeterminada.With regard to the heating stage, it is well known to use a home or oven to calendar the glass sheets to be tempered. Generally speaking, an oven is an oven which can be of the type of continuous rollers, of the type of fixed rollers or gas type. For example, a gas type furnace has a plurality of blocks arranged under a plurality of radiant heaters. Traditionally, a sheet of glass is placed inside the oven where the sheet is heated by conventional radiation, convection and heat conduction. The glass sheet moves along the blocks at a predetermined rate, which depends on the thickness and thermal conductivity of the glass sheet, to reach the temperature in the range of the glass sheet. When said temperature is reached (for example approximately 1200 degrees F), the glass sheet is formed to a predetermined shape.
Una vez que se forma Ia lámina de vidrio, ésta es rápidamente templada por aire, típicamente por Ia aplicación de un flujo de aire a Ia lámina de vidrio. El flujo de aire puede consistir de arreglos de boquillas fijas, rotatorias o reciprocantes. Es importante extraer el calor uniformemente de ambas superficies del vidrio (Ia extracción de calor en forma irregular puede producir arqueaduras o combas) y para sostener el enfriado Io suficientemente largo para prevenir el recalentamiento de Ia superficie de vidrio del centro, aún caliente de Ia lámina de vidrio. La condición de enfriado empieza a ser estable cuando Ia temperatura de Ia lámina de vidrio se reduce de aproximadamente 400 grados C.Once the glass sheet is formed, it is quickly tempered by air, typically by the application of an air flow to the glass sheet. The air flow may consist of fixed, rotary or reciprocating nozzle arrangements. It is important to extract the heat uniformly from both surfaces of the glass (the irregular extraction of heat can produce arches or combas) and to sustain cooling long enough to prevent overheating of the glass surface of the center, still hot of the sheet of glass. The cooling condition begins to be stable when the temperature of the glass sheet is reduced by approximately 400 degrees C.
Aunque el horno antes descrito trabaja bien, este tiene Ia desventaja de que el horno debe ser Io suficientemente largo para permitir que Ia lámina de vidrio sea calentada a una tasa predeterminada.Although the oven described above works well, it has the disadvantage that the oven must be long enough to allow the glass sheet to be heated at a predetermined rate.
El largo del horno requiere de una gran cantidad de espacio de piso, consumo de energía y costos.The oven length requires a large amount of floor space, energy consumption and costs.
Una reciente aproximación para superar esta desventaja es emplear energía de microondas [a frecuencias en el rango de 2 gigahertz (GHz) a 40 GHz] para rápidamente y eficientemente calentar Ia lámina de vidrio que ha sido pre-calentada a una temperatura substancialmente en o por encima de Ia temperatura de ablandamiento a través de medios convencionales.A recent approach to overcome this disadvantage is to use microwave energy [at frequencies in the range of 2 gigahertz (GHz) to 40 GHz] to quickly and efficiently heat the glass sheet that has been pre-heated to a temperature substantially at or by above the softening temperature through conventional means.
La patente Norteamericana No. 5,782,947 de Boaz describe un método para calentar una lámina de vidrio incluyendo las etapas de calentar Ia lámina de vidrio a una primera temperatura predeterminada y aplicar energía de microondas a Ia lámina de vidrio para calentar ésta a Ia menos una segunda temperatura predeterminada para permitir que Ia lámina de vidrio sea formada. Una ventaja del método descrito en Ia Patente Norteamericana No. 5,782,947 asignada a Boaz, es que Ia longitud del horno se reduce, Io cual resulta en un menor espacio de piso e incremento (velocidad y producción) de Ia lámina de vidrio que está siendo formada.U.S. Patent No. 5,782,947 to Boaz describes a method of heating a glass sheet including the steps of heating the glass sheet at a first predetermined temperature and applying microwave energy to the glass sheet to heat it to the at least a second temperature. predetermined to allow the glass sheet to be formed. An advantage of the method described in US Patent No. 5,782,947 assigned to Boaz, is that the length of the furnace is reduced, which results in a lower floor space and increase (speed and production) of the glass sheet being formed .
La patente Norteamericana No. 5,827,345 de Boaz describe un método para calentar, formar y templar una lámina de vidrio que incluye las etapas de calentar Ia lámina de vidrio a al menos una primera temperatura predeterminada, aplicar energía de microondas a Ia lámina de vidrio para calentar ésta a al menos una segunda temperatura predeterminada, formar Ia lámina de vidrio a una configuración predeterminada y, enfriar al menos una superficie externa de Ia lámina de vidrio a al menos una tercera temperatura predeterminada para templar Ia lámina de vidrio. Una ventaja del método descrito en Ia Patente Norteamericana No. 5,827,345 asignada a Boaz es que se puede templar una lámina de vidrio relativamente delgada (por ejemplo menos de 0.125 pulgadas en espesor). Más específicamente, mientras que el centro de Ia lámina de vidrio está siendo calentada por Ia energía de microondas, Ia superficie externa de Ia lámina de vidrio se está enfriando, Io cual crea un gradiente o diferencial de temperatura deseado entre el centro y Ia superficie externa de Ia lámina de vidrio. Aunque los métodos descritos en las Patentes NorteamericanasU.S. Patent No. 5,827,345 to Boaz describes a method for heating, forming and tempering a glass sheet that includes the steps of heating the glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat it to at least a second predetermined temperature, forming the glass sheet to a predetermined configuration and cooling at least an external surface of the glass sheet at at least a third predetermined temperature to temper the glass sheet. An advantage of the method described in US Patent No. 5,827,345 assigned to Boaz is that a relatively thin glass sheet can be tempered (for example less than 0.125 inches in thickness). More specifically, while the center of the glass sheet is being heated by microwave energy, the outer surface of the glass sheet is cooling, which creates a desired temperature gradient or differential between the center and the outer surface. of the glass sheet. Although the methods described in US Pat.
Nos. 5,782,947 y 5,827,345 de Boaz representan avances significativos en Ia tecnología de templado de vidrio, éstos métodos tienen Ia desventaja que los niveles descritos de energía de microondas (por ejemplo teniendo un rango de frecuencia de 2 GH a 40 GH) es relativamente caro generar y mantenerla por sobre un periodo de producción largo. Adicionalmente, el uso de dichos niveles de energía dé microondas de alta frecuencia presenta problemas operacionales en un arreglo de producción convencional. Por Io tanto existe una necesidad en el arte para un sistema y método para rápidamente, eficientemente y en forma económica, calentar el vidrio durante Ia porción de calentamiento del proceso de templado, mientras se mantiene un gradiente o diferencial de temperatura deseado entre el centro del vidrio y Ia superficies externas de Ia lámina de vidrio para facilitar Ia producción del vidrio templado, especialmente templado de vidrio relativamente delgado. Otra forma para el templado de láminas de vidrio se describe en las Patentes Norteamericanas No. 6826929 y 7367205 asignadas a Boaz, que comprenden aplicar energía de radiofrecuencia con una frecuencia dentro de un rango de alrededor de 0.1 GHz a alrededor de 2.0 GHz desde al menos un electrodo hueco a Ia lámina de vidrio para calentar Ia lámina de vidrio a al menos una segunda temperatura predeterminada, y aplicar al menos un flujo de aire a través de al menos uή electrodo hueco de al menos a una superficie exterior de Ia hoja de vidrio para enfriar al menos una superficie exterior de Ia hoja de vidrio a al menos a una tercera temperatura predeterminada para templar Ia hoja de vidrio.Nos. 5,782,947 and 5,827,345 of Boaz represent significant advances in glass tempering technology, these methods have the disadvantage that the described levels of microwave energy (for example having a frequency range of 2 GH to 40 GH) is relatively expensive to generate and keep it over a long production period. Additionally, the use of such high frequency microwave energy levels presents operational problems in a conventional production arrangement. Therefore, there is a need in the art for a system and method to quickly, efficiently and economically heat the glass during the heating portion of the tempering process, while maintaining a desired temperature gradient or differential between the center of the glass and the external surfaces of the glass sheet to facilitate the production of the tempered glass, especially relatively thin tempered glass. Another way to temper glass sheets is described in US Pat. Nos. 6826929 and 7367205 assigned to Boaz, which comprise applying radiofrequency energy with a frequency in a range of about 0.1 GHz to about 2.0 GHz from at least a hollow electrode to the glass sheet to heat the glass sheet to at least a second predetermined temperature, and to apply at least one air flow through at least one hollow electrode of at least one outer surface of the glass sheet to cool at least one outer surface of the glass sheet to at least a third predetermined temperature to temper the glass sheet.
De acuerdo a Io anterior, Ia presente invención está relacionada con un nuevo proceso para el formado y/o templado de paneles de vidrio mediante el cual el vidrio es pre-calentado en un horno convencional a una temperatura que permita que el vidrio sea transferido o formado. Después es transferido a una temperatura conveniente por debajo de Ia temperatura de ablandamiento de 660 grados C. A esta baja temperatura, alrededor de 650 grados el vidrio es suficientemente flexible para ser formado, pero suficientemente rígida para resistir Ia distorsión en un manejo de transferencia normal. Este vidrio relativamente frío en cerca de 640 grados C, (de preferencia entre 620 y 65O0C) es entonces a un horno RW. Dentro del horno RW el vidrio se calienta hasta los 66O0C para que se lleve a cabo una acción de enfriamiento. Dado que el interior del hornoAccording to the foregoing, the present invention is related to a new process for forming and / or tempering glass panels by means of which the glass is pre-heated in a conventional oven at a temperature that allows the glass to be transferred or formed. It is then transferred to a convenient temperature below the softening temperature of 660 degrees C. At this low temperature, around 650 degrees the glass is flexible enough to be formed, but rigid enough to resist distortion in normal transfer handling. . This relatively cold glass at about 640 degrees C, (preferably between 620 and 65O 0 C) is then to an oven RW Inside the RW oven, the glass is heated to 66O 0 C for a cooling action. Since the inside of the oven
RW está a temperatura ambiente, éste también alberga el sistema de enfriamiento y el enfriamiento tiene lugar dentro de Ia cámara antes de que el vidrio pierda cualquier temperatura.lEsto representa una gran diferencia con respecto al proceso de templado térmico convencional.RW is at room temperature, it also houses the cooling system and the cooling takes place inside the chamber before the glass loses any temperature. This represents a great difference with respect to the conventional thermal tempering process.
RESUMEN DE LA INVENCIÓNSUMMARY OF THE INVENTION
Por Io anterior, es una ventaja de Ia presente invención proveer un sistema y a un método para el formado y templado de paneles de vidrio con energía de radiofrecuencia, en el cual Ia aplicación de Ia radio frecuencia y el enfriamiento se llevan a cabo en Ia misma cámara, de tal manera que el calentamiento por radiofrecuencia y el enfriamiento se efectúan dentro de Ia cámara antes de que el vidrio pierda cualquier temperatura. Es otra ventaja de Ia presente invención proveer un sistema y método para el formado y templado de paneles de vidrio con energía de radiofrecuencia para producir vidrio templado.Therefore, it is an advantage of the present invention to provide a system and method for forming and tempering glass panels with radiofrequency energy, in which the application of radio frequency and cooling are carried out therein. chamber, in such a way that radiofrequency heating and cooling are carried out inside the chamber before the glass loses any temperature. It is another advantage of the present invention to provide a system and method for forming and tempering glass panels with radio frequency energy to produce tempered glass.
Otra ventaja de Ia presente invención es proveer un sistema y un método, el cual es particularmente útil para templar vidrio delgado de menos de 3.0 mm de espesor.Another advantage of the present invention is to provide a system and method, which is particularly useful for tempering thin glass of less than 3.0 mm thickness.
Otros objetivos y ventajas de Ia presente invención serán se harán aparentes de Ia siguiente descripción detallada de Ia invención tomada en relación con los dibujos que se acompañan.Other objectives and advantages of the present invention will be apparent from the following detailed description of the invention taken in relation to the accompanying drawings.
BREVE DESCRIPCIÓN DE LOS DIBUJOS La figura 1 es un diagrama de etapas de un sistema y método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con las técnicas de templado convencionales del arte previo. La Figura 2 es una gráfica de temperatura para el templado de hojas de vidrio de una fase de precalentamiento a una etapa de enfriamiento, de conformidad con las técnicas de templado convencionales del arte previo.BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram of stages of a system and method for forming and tempering glass panels with radiofrequency energy according to the conventional tempering techniques of the prior art. Figure 2 is a temperature graph for the tempering of glass sheets from a preheating phase to a cooling stage, in accordance with the conventional tempering techniques of the prior art.
La Figura 3 muestra una gráfica de datos de Ia caída de Ia viscosidad de vidrio calizo en un rango de temperatura de 550°C a 75O0C;Figure 3 shows a graph of data of the viscosity drop Ia soda lime glass in a temperature range of 550 ° C to 75O 0 C;
La Figura 4 es un diagrama de etapas de un sistema y método para el formado y templado de paneles de -vidrio energía de radio frecuencia, de conformidad con Ia presente invención. Figura 5 es una gráfica de temperatura para templado de láminas de vidrio de una etapa de precalentamiento a una etapa de enfriamiento de acuerdo con Ia presente invención.Figure 4 is a diagram of stages of a system and method for forming and tempering panels of high-frequency radio frequency energy, in accordance with the present invention. Figure 5 is a temperature graph for tempering glass sheets from a preheating stage to a cooling stage according to the present invention.
La figura 6 es una primera vista en perspectiva del sistema para formar una lámina de vidrio templada, de conformidad con Ia presente invención.Figure 6 is a first perspective view of the system for forming a sheet of tempered glass, in accordance with the present invention.
La figura 7 es vista en perspectiva de Ia segunda modalidad del sistema para formar una lámina de vidrio templado, de conformidad con Ia presente invención.Figure 7 is a perspective view of the second mode of the system to form a sheet of tempered glass, in accordance with the present invention.
La figura 8 es una vista en perspectiva de una tercera modalidad del sistema y método para el formado y templado de paneles de vidrio templado con energía de radio frecuencia, de conformidad con Ia presente invención; y,Figure 8 is a perspective view of a third embodiment of the system and method for forming and tempering glass panels. tempered with radio frequency energy, in accordance with the present invention; Y,
La Figura 9 muestra una fotografía del patrón de ruptura de un vidrio de 3.00 mm junto con las lecturas de compresión de Ia superficie y los datos de tamaño máximo de partículas.Figure 9 shows a photograph of the breaking pattern of a 3.00 mm glass together with the compression readings of the surface and the maximum particle size data.
Las figuras 10 a 13 son fotografías similares de espesores de vidrio hasta 2,00 mm. DESCRIPCIÓN DE LAS MODALIDADES PREFERIDASFigures 10 to 13 are similar photographs of glass thicknesses up to 2.00 mm. DESCRIPTION OF THE PREFERRED MODES
En relación a las figuras 1 y 2, describen un sistema y método para el templado de paneles de vidrio con radio frecuencia, con técnicas de templado comunes. La Figura 1 ilustra una secuencia del proceso de templado común y una de las dificultades físicas que surgen es que requiere de una elevación de temperatura hasta 66O0C para que pueda iniciar Ia operación de enfriamiento. Con referencia a Ia figura 1 , el vidrio es calentado en un horno convencional 1 y luego se transfiere a una cámara de 2, donde éste es formado (si es necesario) y luego se transfiere una cámara de separación 3 para Ia operación de enfriamiento. Para llevar a cabo el proceso de templado, el vidrio debe estar a un mínimo de 66O0C para que el templado pueda ser llevado a cabo. Sin embargo, el vidrio pierde su temperatura muy rápidamente (hasta en 25 grados/seg., en vidrio delgados de menos de 3,0 mm de espesor) antes del inicio de Ia etapa de enfriamiento en Ia estación de enfriamiento 3. Para superar esta pérdida de temperatura, Ia solución convencional es sobre calentar Ia última zona del horno de precalentamiento 4 (sección 2 de Ia figura 2), hasta aproximadamente 7000C, y pasar el vidrio a través de esta zona a una velocidad rápida. Esto hace uso de las propiedades del vidrio que durante un rápido aumento en Ia temperatura del vidrio, Ia viscosidad del vidrio va por detrás. Sin embargo, en el caso de un vidrio más delgado de 3.0 mm, esta solución es inadecuada. La figura 2 muestra Ia historia térmica del vidrio con más detalle.In relation to figures 1 and 2, they describe a system and method for tempering glass panels with radio frequency, with common tempering techniques. Figure 1 illustrates a sequence of the common tempering process and one of the physical difficulties that arise is that it requires a temperature rise up to 66O 0 C so that it can initiate the cooling operation. With reference to Figure 1, the glass is heated in a conventional oven 1 and then transferred to a chamber 2, where it is formed (if necessary) and then a separation chamber 3 is transferred for the cooling operation. To carry out the tempering process, the glass must be at a minimum of 66O 0 C so that tempering can be carried out. However, the glass loses its temperature very quickly (up to 25 degrees / sec., In thin glass less than 3.0 mm thick) before the start of the cooling stage in the cooling station 3. To overcome this Loss of temperature, the conventional solution is to heat the last zone of the preheating furnace 4 (section 2 of Figure 2), up to approximately 700 0 C, and pass the glass through from this area at a fast speed. This makes use of the properties of the glass that during a rapid increase in the temperature of the glass, the viscosity of the glass goes behind. However, in the case of a thinner glass of 3.0 mm, this solution is inadequate. Figure 2 shows the thermal history of the glass in more detail.
La Sección 1 muestra Ia porción de pre-calentamiento de Ia preparación del vidrio para Ia operación de templado. La sección 2 describe el aumento adicional de Ia temperatura requerida en Ia sección de pre- calentamiento para compensar Ia pérdida de calor durante Ia transferencia a Ia zona de enfriamientojLa Sección 3 indica Ia pérdida de temperatura actual del panel de vidrio antes del inicio del enfriamiento en Ia sección 4.Section 1 shows the pre-heating portion of the glass preparation for the tempering operation. Section 2 describes the additional increase in the temperature required in the preheating section to compensate for the loss of heat during the transfer to the cooling zone. Section 3 indicates the current temperature loss of the glass panel prior to the start of cooling in Ia section 4.
La sección 3 representa el área de transferencia en Ia figura 2, donde residen las dificultades físicas antes mencionadas. A temperaturas superiores a los 660 grados C, que es requerido para el inicio de Ia sección 4, Ia viscosidad del vidrio cae muy rápidamente y Ia manipulación física del vidrio tiende a impartir distorsiones ópticas sobre el panel. Este problema se vuelve aún más grave cuando los paneles están "delgados" tal como por debajo de los 3,0 mm de espesor. El enfriamiento normalmente se realiza con aire forzado sobre Ia superficie de vidrio, extrayendo calor a un ritmo rápido para enfriar Ia superficie exterior T2 mientras que Ia parte interior T1 está aún suave. El mayor enfriamiento de Ia contracción térmica de Ia parte interior crea una tensión de compresión fuerte en Ia superficie exterior enfriada mientras que una tensión de tracción es inducida en Ia parte interior. La Figura 3 muestra una gráfica de datos de Ia caída de Ia viscosidad del vidrio calizo durante rango de temperatura de nuestra preocupación. La figura 3 en Ia escala Log muestra que Ia viscosidad actual cae por un factor de más de tres entre 630 y 6600C. Es esta caída extrema en Ia viscosidad Ia que presenta un grave problema de procesamiento cuando éste vidrio suave tiene que ser transportado desde el Ia zona de calentamiento en Ia zona de enfriamiento sin provocar ninguna distorsión óptica. EL NUEVO PROCESO El nuevo proceso consiste en una forma única para formar y/o templar paneles de vidrio. La Figura 4 describe el nuevo proceso en el cual el vidrio es pre-calentado en un horno convencional 5 hasta una temperatura que permite que el vidrio pueda ser transferidos o formado (6). Este es entonces trasferido a una temperatura conveniente por debajo de Ia temperatura de ablandamiento de 660°C. A una temperatura más baja, de aproximadamente 650 grados C1 el vidrio es suficientemente flexible para ser formado, pero suficientemente rígido para resistir Ia distorsión del manejo de transferencia normal. Este vidrio relativamente frío de alrededor de unos 640°C, (de preferencia entre 620 y 650° C) se transfiere entonces a un horno de radio frecuencia 7. Dentro del horno de radio frecuencia, el vidrio se calienta hasta los 660° C para que se efectúe Ia acción de enfriamiento. Dado que el interior del horno de radio frecuencia 7 está a una temperatura ambiente, éste también alberga el sistema de enfriamiento y Ia etapa de enfriamiento tiene lugar dentro del horno 7 antes de que el vidrio disminuya su temperatura. La Figura 5 presenta una historia térmica detallada del nuevo proceso. La sección 1A representa el pre-calentamiento del vidrio en un horno convencional. La sección 2A muestra Ia operación de formado del vidrio en alrededor de 6500C. La sección 3A muestra el vidrio que está siendo calentado hasta Ia temperatura de enfriamiento de 6600C, por medio de energía de radio frecuencia. La energía de radio frecuencia es aplicada de preferencia en alrededor de unos 20 Mega Hertz. A esta frecuencia, el aparato está disponible comercialmente y tiene un historial probado de seguridad en Ia planta. La sección 4A muestra Ia operación de enfriamiento dentro de Ia misma sección 4A de Ia figura 4, en donde T1 representa Ia temperatura de Ia superficie interior y T2 representa Ia temperatura de Ia superficie exterior. El enfriamiento es cual normalmente es realizado con aire forzado sobre Ia superficie de vidrio, para Ia extracción a gran velocidad para enfriar Ia superficie exterior T2 mientras que Ia parte interior T1 está aún suave. La etapa de enfriamiento reduce Ia temperatura de Ia hoja de vidrio tratada a una temperatura dentro del rango de unos 415 ° C a 200 ° C.Section 3 represents the transfer area in Figure 2, where the physical difficulties mentioned above reside. At temperatures above 660 degrees C, which is required for the beginning of section 4, the viscosity of the glass drops very quickly and the physical manipulation of the glass tends to impart optical distortions on the panel. This problem becomes even more serious when the panels are "thin" such as below 3.0 mm thick. The cooling is normally carried out with forced air on the glass surface, extracting heat at a rapid rate to cool the outer surface T2 while the inner part T1 is still soft. The greater cooling of the thermal contraction of the inner part creates a strong compression tension in the cooled outer surface while a tensile tension is induced in the inner part. Figure 3 shows a graph of data of the drop in the viscosity of the limestone glass during the temperature range of our concern. Figure 3 in the Log scale shows that the current viscosity falls by a factor of more than three between 630 and 660 0 C. It is this extreme drop in viscosity Ia that presents a serious processing problem when this soft glass has to be transported from the heating zone in the cooling zone without causing any optical distortion. THE NEW PROCESS The new process consists of a unique way to form and / or temper glass panels. Figure 4 describes the new process in which the glass is pre-heated in a conventional oven 5 to a temperature that allows the glass to be transferred or formed (6). This is then transferred at a convenient temperature below the softening temperature of 660 ° C. At a lower temperature of approximately 650 degrees C 1, the glass is flexible enough to be formed, but rigid enough to withstand the distortion of normal transfer handling. This relatively cold glass of about 640 ° C, (preferably between 620 and 650 ° C) is then transferred to a radio frequency oven 7. Inside the radio frequency oven, the glass is heated to 660 ° C to that the cooling action be performed. Since the interior of the radio frequency oven 7 is at an ambient temperature, it also houses the cooling system and the cooling stage takes place inside the oven 7 before the glass decreases its temperature. Figure 5 presents a detailed thermal history of the new process. Section 1A represents the preheating of the glass in a conventional oven. Section 2A shows the operation of forming the glass at about 650 0 C. Section 3A shows the glass that is being heated to the cooling temperature of 660 0 C, by means of radio frequency energy. Radio frequency energy is preferably applied in about 20 Mega Hertz. At this frequency, the device is commercially available and has a proven safety record in the plant. Section 4A shows the cooling operation within the same section 4A of Figure 4, where T1 represents the temperature of the inner surface and T2 represents the temperature of the outer surface. The cooling is which is normally carried out with forced air on the glass surface, for high speed extraction to cool the outer surface T2 while the inner part T1 is still soft. The cooling stage reduces the temperature of the treated glass sheet to a temperature within the range of about 415 ° C to 200 ° C.
Un enfriamiento adicional de Ia contracción térmica de Ia parte interior, crea una tensión de compresión fuerte en Ia superficie exterior enfriada, mientras que una tensión de tracción es inducida en Ia parte interior.An additional cooling of the thermal contraction of the inner part creates a strong compression tension on the cooled outer surface, while a tensile stress is induced on the inner part.
Cabe señalar que el vidrio cuando es calentado de forma rápida con energía RW, no muestra el mismo comportamiento de caída/pandeo que por Io general se espera cuando el vidrio se calienta a Ia misma velocidad por métodos convencionales tales como Ia radiación, convección y conducción. Por ejemplo, cuando el vidrio se calienta por RW a una tasa de 100C por segundo, tiende a caer casi de inmediato cuando se alcanza su punto de reblandecimiento. Además, el calentamiento por RW parece permitir un alto nivel de estrés de templado para ser desarrollado, incluso con enfriamiento de aire convencional después de un rápido aumento de Ia temperatura, hasta el punto de reblandecimientoJSe sospecha que el calentamiento por RW en el vidrio es capaz de variar Ia viscosidad del cuerpo del vidrio al unísono con el aumento de Ia temperatura, incluso cuando el vidrio se calienta a un ritmo elevado. Este comportamiento parece ser contrario a nuestra observación de los métodos convencionales de calentamiento.It should be noted that when the glass is rapidly heated with RW energy, it does not show the same fall / buckling behavior that is generally expected when the glass is heated at the same speed by conventional methods such as radiation, convection and conduction For example, when the glass is heated by RW at a rate of 10 0 C per second, it tends to fall almost immediately when its softening point is reached. In addition, heating by RW seems to allow a high level of tempering stress to be developed, even with conventional air cooling after a rapid increase in temperature, to the point of softening J It is suspected that heating by RW in the glass is capable to vary the viscosity of the glass body in unison with the increase in temperature, even when the glass is heated at a high rate. This behavior seems to be contrary to our observation of conventional heating methods.
La figura 6 muestra una configuración típica de los electrodos dentro de una cámara de radiofrecuencia. Los dos haces de electrodos de 10 y 11 , el positivo y el negativo se colocan cerca de Ia lámina de vidrio 13 y en toda Ia anchura de dicha lámina de vidrio de 13 para proporcionar Ia máxima exposición al campo de onda de radiofrecuencia que existe entre las dos terminales. Sopladores de aire 14 y 15 son provistos por encima y por debajo del vidrio para enfriar el vidrio 13, cuando se alcanza Ia temperatura requerida de 66O0C. El tiempo a partir del cual se detiene el calentamiento y se inicia el enfriamiento están controlados en fracciones de segundo. El vidrio se apoya sobre los rodillos 16, que consiste de anillos de cerámica 17 especialmente diseñado para Ia aplicación de radio frecuencia. Los anillos y los rodillos permiten el flujo libre de aire que es esencial para el proceso de enfriamiento. Una modalidad adicional del proceso se describe en Ia Figura 7. En esta modalidad el vidrio a una temperatura conveniente de alrededor de unos 63O0C (entre 620 y 65O0C) se transfiere de Ia sección de pre- calentamiento 5 a un conjunto de rodillos 16. Los rodillos 16 están dispuestos en un arco que representa un radio R, en el cual el vidrio formado y templado tiene Ia intención de adherirse. Normalmente, por ejemplo, algunos de vidrio de Ia puerta del automóvil requiere un radio de 30". Después de que el vidrio llega a este lugar, se aplica Ia energía de radio frecuencia y Ia onda de radio frecuencia, como se describió anteriormente calienta el vidrio a unos 6600C. A esta temperatura el vidrio comienza a "pandearse" en el arco de los rodillos. En el momento apropiado, el aire de enfriamiento es encendido para templar el panel.Figure 6 shows a typical configuration of the electrodes within a radiofrequency chamber. The two electrode beams of 10 and 11, the positive and the negative are placed near the glass sheet 13 and across the entire width of said glass sheet 13 to provide maximum exposure to the radiofrequency wave field that exists between The two terminals. Air blowers 14 and 15 are provided above and below the glass to cool the glass 13, when the required temperature of 66O 0 is reached. The time after which the heating stops and the cooling begins are controlled in fractions of a second The glass rests on the rollers 16, which consists of ceramic rings 17 specially designed for the application of radio frequency. The rings and rollers allow the free flow of air that is essential for the cooling process. An additional modality of the process is described in Figure 7. In this mode the glass at a convenient temperature of about 63O 0 C (between 620 and 65O 0 C) is transferred from the preheating section 5 to a set of rollers 16. The rollers 16 are arranged in an arc representing a radius R, in which the formed and tempered glass intends to adhere. Normally, for example, some of the glass of the car door requires a radius of 30 ". After the glass reaches this place, the radio frequency energy and the radio frequency wave are applied, as described above heats the glass at about 660 0 C. At this temperature the glass begins to "pande" in the arc of the rollers At the appropriate time, the cooling air is turned on to temper the panel.
Una modalidad adicional de este proceso es aplicable a vidrios comerciales para grandes ventanas de Ia categoría "vidrio grueso", generalmente en el rango de 6,0 a 10,0 mm de espesor. Estos paneles de vidrio presentan un problema único para ser templados dado que se introduce un gradiente de temperatura grande a Io largo de su longitud durante Ia transferencia del pre-calentamiento a Ia cámara de enfriamiento. El extremo inicial principal pierde gran parte de Ia temperatura antes de que extremo final esté fuera del horno de pre- calentamiento. Este gradiente puede ser compensada por el aumento de Ia temperatura de salida del horno de precalentamiento. Sin embargo, esto resulta en una distorsión de Ia superficie. Al mover el vidrio a una temperatura relativamente baja, tal como en 6200C a Ia cámara de radio frecuencia y volver a calentar el vidrio a una temperatura uniforme de 660°C con calor de radio frecuencia y luego de arrancar el sistema de enfriamiento, se puede introducir un templado uniforme en el vidrio grueso. Por ejemplo, como se muestra en Ia Figura 8, los electrodos de 11 , 12, son colocados para calentar de forma selectiva Ia porción de entrada del vidrio a un ritmo mayor que Ia parte trasera. Al variar Ia distancia entre los dos electrodos 11 y 12, es posible variar Ia intensidad del campo de ondas de radio frecuencia que se aplica al vidrio. Esto da como resultado que el extremo delantero del vidrio recibe más energía de radio frecuencia y su temperatura se aproxima a Ia del extremo final. Esto también se traduce en ahorro de energía en Ia sección de pre- calentamiento en el proceso.An additional modality of this process is applicable to commercial glass for large windows of the "thick glass" category, generally in the range of 6.0 to 10.0 mm thick. These glass panels present a unique problem to be tempered since a large temperature gradient is introduced along its length during the transfer of the preheating to the cooling chamber. The main initial end loses a large part of the temperature before the final end is outside the preheating oven. This gradient can be compensated by the increase in the preheating oven outlet temperature. However, this results in a distortion of the surface. When moving the glass at a relatively low temperature, such as 620 0 C to the radio frequency chamber and reheating the glass to a uniform temperature of 660 ° C with radio frequency heat and after starting the cooling system, a uniform tempering can be introduced into the thick glass. For example, as shown in Figure 8, the electrodes of 11, 12, are placed to selectively heat the inlet portion of the glass at a rate greater than the rear. By varying the distance between the two electrodes 11 and 12, it is possible to vary the intensity of the radio frequency wave field that is applied to the glass. This results in the front end of the glass receiving more radio frequency energy and its temperature approaching that of the end end. This also translates into energy savings in the preheating section in the process.
Una de las ventajas más significativas del proceso de templado por radio frecuencia (RW) es para su aplicación a vidrio "delgados". Mientras que el proceso convencional se acerca a límite de vidrios de 3.0 y 2.9 mm, el proceso de radiofrecuencia (RW) es capaz de templar vidrio con un espesor de hasta 2.00 mm o menos.One of the most significant advantages of the radio frequency tempering (RW) process is for its application to "thin" glass. While the conventional process is close to the 3.0 and 2.9 mm glass limit, the radiofrequency (RW) process is capable of tempering glass with a thickness of up to 2.00 mm or less.
Se llevaron a cabo pruebas experimentales en paneles de vidrio de 12 x 12 pulgadas de paneles, de diferentes espesores, los cuales fueron templados en un laboratorio de tecnología. Algunos de los resultados se muestran en las Figuras 9 a 13. La figura 9 muestra una fotografía del patrón de rotura del vidrio de 2,7 mm conjuntamente con las lecturas de Ia superficie de compresión y los datos de tamaño máximo de partículas. Fotografías similares se muestran en las figuras 10 a 13 para espesores de vidrio hasta de 2,00 mm. En conclusión, se espera que Ia capacidad para templar vidrio delgado de 2.7 mm o menos tenga un enorme impacto en Ia industria del vidrio plano en cuanto a Ia necesidad de materia prima.Experimental tests were carried out on 12 x 12-inch glass panels of panels, of different thicknesses, which were tempered in a technology laboratory. Some of the results are shown in Figures 9 to 13. Figure 9 shows a photograph of the glass breakage pattern of 2.7 mm together with the readings of the compression surface and the maximum particle size data. Similar photographs are shown in Figures 10 to 13 for glass thicknesses up to 2.00 mm. In conclusion, the ability to temper thin glass of 2.7 mm or less is expected to have an enormous impact on the flat glass industry in terms of the need for raw materials.
No obstante que Ia presente invención ha sido descrita con diferentes modalidades, muchas otras modificaciones y variaciones de Ia presente invención son posibles a Ia luz de las enseñanzas anteriores. Por Io tanto, dentro del campo de las reivindicaciones que se acompañan, Ia presente invención podrá ser realizada en otras formas como Ia que específicamente se han descrito. Although the present invention has been described with different modalities, many other modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be carried out in other forms such as that specifically described.

Claims

REIVINDICACIONES
1. Un método para el formado y templado de paneles de vidrio con energía de radiofrecuencia comprendiendo: pre-calentar una lámina de vidrio a al menos a una primera temperatura predeterminada en o por debajo de una temperatura de reblandecimiento de Ia lámina de vidrio; aplicar energía de radiofrecuencia para calentar Ia lámina de vidrio en o ligeramente por debajo de Ia temperatura de reblandecimiento de Ia lámina de vidrio precalentada; y, enfriar Ia lámina de vidrio para producir una lámina de vidrio templado. 2. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 1 , incluido Ia etapa de formar Ia lámina de vidrio a Ia forma deseada a una temperatura de entre 620 y 6500C después de dicha etapa de precalentamiento. 3. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 1 , donde Ia temperatura de reblandecimiento es de aproximadamente 66O0C. ϊ|4. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde el calentamiento de Ia lámina de vidrio en o por encima de una temperatura de reblandecimiento es igual o superior a 66O0C.1. A method for forming and tempering glass panels with radiofrequency energy comprising: preheating a glass sheet to at least a first predetermined temperature at or below a softening temperature of the glass sheet; apply radiofrequency energy to heat the glass sheet at or slightly below the softening temperature of the preheated glass sheet; and, cooling the glass sheet to produce a tempered glass sheet. 2. The method for forming and tempering glass panels with radio frequency energy in accordance with claim 1, including the step of forming the sheet of glass to the desired shape at a temperature of between 620 and 650 0 C after said preheating stage. 3. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein the softening temperature is approximately 66O 0 C. ϊ | 4. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein the heating of the glass sheet at or above a softening temperature is equal to or greater than 66O 0 C.
5. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 2, donde Ia temperatura de reblandecimiento está en el rango de unos 62O0C a 65O0C. 5. The method for forming and tempering glass panels with radiofrequency energy according to claim 2, wherein the softening temperature is in the range of about 62O 0 C to 65O 0 C.
6. El método. para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1, donde Ia energía de radiofrecuencia es una frecuencia de alrededor de 20 MHz.6. The method. for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein the radiofrequency energy is a frequency of about 20 MHz.
7. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde dicha etapa de pre-calentamiento comprende, transferir Ia lámina de vidrio a Ia etapa de radio frecuencia a una temperatura por debajo de Ia temperatura de reblandecimiento de 66O0C.7. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein said pre-heating stage comprises transferring the glass sheet to the radio frequency stage at a temperature below of the softening temperature of 66O 0 C.
8. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde8. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein
Ia energía de radio frecuencia y el enfriamiento se llevan a cabo en lamisca etapa, antes que el vidrio pierda cualquier temperatura.The radio frequency energy and cooling are carried out in the same stage, before the glass loses any temperature.
9. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde dicha etapa de enfriamiento comprende aplicar al menos una corriente de aire a al menos una superficie exterior de Ia lámina de vidrio tratada, cuando Ia temperatura necesaria para enfriamiento es alcanzada.9. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein said cooling step comprises applying at least one stream of air to at least one outer surface of the sheet of treated glass , when the temperature necessary for cooling is reached.
10. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde dicha etapa de pre-calentamiento de Ia lámina de vidrio a al menos una primera temperatura predeterminada comprende calentar ya sea con energía infrarroja o energía por convección.10. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein said preheating stage of the glass sheet at least a first predetermined temperature comprises heating with either energy infrared or convection energy.
11. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , que incluye la etapa de variar Ia intensidad de Ia energía de radio frecuencia que se aplica al vidrio.11. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, which It includes the step of varying the intensity of the radio frequency energy that is applied to the glass.
12. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , incluyendo Ia etapa de mover el vidrio hacia Ia etapa de radio frecuencia a una temperatura relativamente baja de alrededor de 62O0C, y recalentar el vidrio a una temperatura uniforme de 66O0C con energía de radio frecuencia.12. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, including the step of moving the glass towards the radio frequency stage at a relatively low temperature of about 62O 0 C, and reheat the glass to a uniform temperature of 66O 0 C with radio frequency energy.
13. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde dicha etapa de enfriamiento reduce Ia temperatura de las láminas de vidrio tratados a una temperatura dentro de un rango de alrededor de 4150C a alrededor de 2000C.13. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein said cooling stage reduces the temperature of the treated glass sheets to a temperature within a range of about 415 0 C to about 200 0 C.
14. El método para el formado y templado de paneles de vidrio con energía de radiofrecuencia de acuerdo con Ia reivindicación 1 , en donde14. The method for forming and tempering glass panels with radiofrequency energy according to claim 1, wherein
Ia lámina de vidrio es inferior 3.0 mm de espesor.The glass sheet is less than 3.0 mm thick.
15. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia que comprende: una sección de pre- calentamiento adaptada para elevar Ia temperatura de una lámina de vidrio a una temperatura igual o inferior a una temperatura de reblandecimiento de Ia lámina de vidrio, y una sección de radiofrecuencia/enfriamiento que tiene al menos una fuente de radio frecuencia adaptada para aplicar energía de radio frecuencia para calentar Ia lámina de vidrio en o por encima de una temperatura de reblandecimiento de Ia lámina de vidrio precalentada y, una sección de enfriamiento adaptada para rápidamente y simultáneamente enfriar Ia hoja de vidrio para producir una hoja de vidrio templado.15. A system for forming and tempering glass panels with radiofrequency energy comprising: a preheating section adapted to raise the temperature of a glass sheet to a temperature equal to or less than a softening temperature of the sheet of glass, and a radiofrequency / cooling section having at least one radio frequency source adapted to apply radio frequency energy to heat the glass sheet at or above a softening temperature of the preheated glass sheet and, a section from cooling adapted to quickly and simultaneously cool the glass sheet to produce a tempered glass sheet.
16. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 15 donde fuente de radio frecuencia emite energía teniendo una frecuencia dentro de un rango de alrededor de 20 Mhz.16. A system for forming and tempering glass panels with radiofrequency energy according to claim 15 wherein radio frequency source emits energy having a frequency within a range of about 20 Mhz.
17. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 15, en donde dicha sección de enfriamiento incluye medios de enfriamiento que se colocados por encima y/o por debajo de Ia lámina de vidrio precalentada para aplicar aire a Ia lámina de vidrio a través de dicha sección de radio frecuencia/enfriamiento.17. A system for forming and tempering glass panels with radio frequency energy according to claim 15, wherein said cooling section includes cooling means that are placed above and / or below the preheated glass sheet to apply air to the glass sheet through said radio frequency / cooling section.
18. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 15, en donde dicha fuente de energía de radio frecuencia incluye una pluralidad de electrodos, dichos electrodos se colocan cerca de Ia lámina de vidrio y en toda Ia anchura del vidrio, cada uno de dichos electrodos teniendo una porción terminal situado Io más cerca posible y en relación de no contacto con una superficie exterior de Ia lámina de vidrio y adaptada para calentar Ia lámina de vidrio.18. A system for forming and tempering glass panels with radio frequency energy according to claim 15, wherein said radio frequency energy source includes a plurality of electrodes, said electrodes are placed near the glass sheet and throughout the entire width of the glass, each of said electrodes having a terminal portion located as close as possible and in relation to no contact with an outer surface of the glass sheet and adapted to heat the glass sheet.
19. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 18, en donde Ia distancia de los electrodos es ajustada con el fin de variar Ia intensidad de Ia energía de radio frecuencia que se aplica a Ia lámina de vidrio. 19. A system for forming and tempering glass panels with radio frequency energy according to claim 18, wherein the distance of the electrodes is adjusted in order to vary the intensity of the radio frequency energy that is applied to The glass sheet.
20. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 15, en donde dicha sección de precalentamiento y dicha sección radio frecuencia/enfriamiento incluye una serie de rodillos operables selectivamente que giran en una dirección deseada para introducir Ia hoja de vidrio de dicha sección de precalentamiento a dicho sección de radio frecuencia, en una dirección particular.20. A system for forming and tempering glass panels with radiofrequency energy in accordance with claim 15, wherein said preheating section and said radio frequency / cooling section includes a series of selectively operable rollers that rotate in a desired direction to introduce the glass sheet of said preheating section to said radio frequency section, in a particular direction.
21. Un sistema para el formado y templado de paneles de vidrio con energía de radiofrecuencia de conformidad con Ia reivindicación 15, en donde Ia lámina de vidrio para templado es de menos de 3.0 mm de espesor. 21. A system for forming and tempering glass panels with radiofrequency energy according to claim 15, wherein the tempered glass sheet is less than 3.0 mm thick.
PCT/MX2010/000022 2009-03-19 2010-03-19 System and method for forming and tempering glass panels with radio frequency energy WO2010107293A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8769990B2 (en) 2010-03-30 2014-07-08 Asahi Glass Company, Limited Method for tempering glass sheet, and apparatus therefor
CN106630567A (en) * 2016-12-15 2017-05-10 郑州航空工业管理学院 Processing technology of high-flatness tempered glass

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US2178520A (en) * 1936-07-01 1939-10-31 Hartford Empire Co Method of tempering glass
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WO2004026775A2 (en) * 2002-09-19 2004-04-01 Boaz Premakaran T System and method for simultaneously meating and cooling glass to produce tempered glass
WO2006048775A1 (en) * 2004-11-05 2006-05-11 Boaz Premakaran T Apparatus and method for tempering glass containers using radio-frequency

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US2178520A (en) * 1936-07-01 1939-10-31 Hartford Empire Co Method of tempering glass
US5827345A (en) * 1995-09-07 1998-10-27 Ford Global Technologies, Inc. Method for heating, forming and tempering a glass sheet
WO2004026775A2 (en) * 2002-09-19 2004-04-01 Boaz Premakaran T System and method for simultaneously meating and cooling glass to produce tempered glass
WO2006048775A1 (en) * 2004-11-05 2006-05-11 Boaz Premakaran T Apparatus and method for tempering glass containers using radio-frequency

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8769990B2 (en) 2010-03-30 2014-07-08 Asahi Glass Company, Limited Method for tempering glass sheet, and apparatus therefor
CN106630567A (en) * 2016-12-15 2017-05-10 郑州航空工业管理学院 Processing technology of high-flatness tempered glass

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