WO2024061987A1 - Cuve de fusion de verre - Google Patents

Cuve de fusion de verre Download PDF

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Publication number
WO2024061987A1
WO2024061987A1 PCT/EP2023/075974 EP2023075974W WO2024061987A1 WO 2024061987 A1 WO2024061987 A1 WO 2024061987A1 EP 2023075974 W EP2023075974 W EP 2023075974W WO 2024061987 A1 WO2024061987 A1 WO 2024061987A1
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WO
WIPO (PCT)
Prior art keywords
glass
electrodes
section
raised
melting tank
Prior art date
Application number
PCT/EP2023/075974
Other languages
German (de)
English (en)
Inventor
Alexander Sorg
Dirk SCHNURPFEIL
Clemens Eidmann
Volker Müller
Thomas Breitfelder
Original Assignee
Beteiligungen Sorg Gmbh & Co. Kg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beteiligungen Sorg Gmbh & Co. Kg filed Critical Beteiligungen Sorg Gmbh & Co. Kg
Publication of WO2024061987A1 publication Critical patent/WO2024061987A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/02—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating
    • C03B5/027—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating by passing an electric current between electrodes immersed in the glass bath, i.e. by direct resistance heating
    • C03B5/03—Tank furnaces
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/42—Details of construction of furnace walls, e.g. to prevent corrosion; Use of materials for furnace walls

Definitions

  • the present invention relates to a glass melting tank for fully electric heating of the glass melt in the production operating state, a glass melting system and a method for producing a glass melting tank.
  • Tubs for producing a glass melt generally have a base and a side wall surrounding the interior of the tub.
  • the glass melt is arranged in the interior of the tub and is delimited laterally by the bottom and by the wall.
  • the interior of the tub is also often at least partially covered by a roof in order to reduce the loss of heat energy and/or the release of exhaust gases and dust.
  • the glass melt flows during a melting, refining and homogenization process in a flow direction from a melting area, in which raw material mixtures and optionally shards are introduced into the tub interior, to at least one outlet opening through which the molten glass is withdrawn.
  • the withdrawn molten glass can be used, for example, to produce container glass, flat glass, rolled glass, fiberglass, glass fibers, household glass or technical glasses.
  • So-called cold-top tanks typically have a complete covering of raw materials (mixture of raw materials and/or shards) that is arranged on top of the glass melt and whose temperature is significantly below the temperature of the glass melt and is therefore referred to as "cold".
  • the “cold” covering has the well-known advantage that it is thermally insulating and serves as a resource-saving condensate trap.
  • the glass flows in a vertical direction, ie from top to bottom, and is drawn off in the area of the floor or to the side of it.
  • Fully electrically heated glass melting tanks are known and are used today in particular for a smaller glass throughput (conveying capacity/melting capacity/tonnage) for good quality glass in the range of a maximum of 250 t of glass melt/day.
  • a glass melting tank with electrical heating is known, in which the tank interior has the shape of a complete 6-sided prism, with the electrodes protruding from the side wall into the glass melt.
  • the glass melting tank shown in the document DE 34 05 273 C2 also has the same shape of the tank interior, with the electrodes in this variant being designed as top electrodes.
  • An electrically heated, cuboid tub interior with a horizontal flow direction of the glass melt is disclosed in the document US 3,885,945.
  • Glass melting tanks with fully electric heating today primarily work according to the cold top principle, i.e. with a "cold" raw material mixture and/or cullet blanket arranged on the glass bath.
  • an electrically heated glass melting tank which has four parallel rows of electrodes, each electrode being arranged on a raised base section and protruding upwards from there into the glass melt.
  • a feed channel is arranged between the two outer rows of electrodes and runs parallel to the rows of electrodes, which are connected to a collecting channel arranged between the two central rows of electrodes.
  • the collecting channel also runs parallel to the rows of electrodes and opens directly into the outlet of the glass melting tank, with the collecting channel having the same width as the outlet.
  • the publications JP S60-24055 B2 and JP S61 -222928 A also describe electrically heated glass melting tanks, the tank interior like this is designed so that the glass melt is arranged in a wider upper section (with a larger diameter) and a narrower section underneath (with a smaller diameter). In both sections, i.e. also in the narrower section, the glass melt is heated using the electrodes.
  • the object of the present invention is therefore to create a compact glass melting tank which can be completely heated electrically in the production operating state, delivers good glass quality and is suitable for medium to large glass throughputs. Furthermore, the task is to provide a cost-effective and simple process for producing such a glass melting tank.
  • the above task is solved by a glass melting tank with the features of claim 1 and a method for its production with the features of claim 14.
  • the above task is further solved by a glass melting system which has the features of claim 13.
  • a glass melting tank for fully electric heating of a glass melt arranged in a tank interior in the production operating state, with a stepped bottom and with a side wall, the bottom delimiting the bottom of the tank interior and the side wall laterally enclosing the tank interior, in Production operating state, the glass melt is arranged in the tub interior, the hot space side of the side wall above an elevated floor section forming an at least 5-sided polygon, for example at least a 6-sided polygon, a circle or an ellipse in horizontal cross section, with the floor at least along 70% of the circumference of the tub interior surrounding raised floor section, preferably at least along 80% of the circumference of the tub interior circumferential raised floor section, and a central, surrounded by the raised floor section, with respect to this lower-lying homogenization floor section, wherein the raised floor section is from the hot room side the side wall extends laterally in the direction of the tub interior and has a width B that is greater than or equal to 0.25 x D, where D
  • the glass melting tank according to the invention has a tank interior which is delimited at the bottom by the bottom and along the largest extent of the glass melting tank laterally by the wall made of refractory material.
  • the side wall includes all of the outermost side walls of the glass melting tank, but not the transition wall arranged between the raised base section and the homogenizing base section.
  • the glass melt is arranged in the interior of the tub.
  • a hot room side of the side wall facing the glass melt above the raised floor section has the shape of at least 5-sided in horizontal cross section Polygon (i.e. not a rectangular shape), a circle or an ellipse or a shape close to these geometric shapes.
  • “Essentially” means here that the hot space side of the side wall can have recesses and steps that are not taken into account when considering the general shape of these surfaces. This shape is assumed by the side wall, particularly in the vertical section of the glass melting tank, which lies above the raised bottom section in the area of the glass stand depth and the coverage of the glass melt. It is important that the flow direction of the glass melt when viewed macroscopically/as a whole in the production operating state essentially runs from top to bottom, i.e. from the surface of the glass melt to the bottom of the glass melting tank (namely to the bottom in the area of the homogenization bottom section).
  • the status “in production” of the glass melting tank means that the glass melted in the glass melting tank and drawn off through at least one outlet opening is used for the production of flat glass, hollow glass, fiber glass or special glass.
  • the hot room side of the side wall or the transition wall can either have a curved shape (ie the shape of a (partial) cylindrical surface) or can be straight in sections, i.e. the shape of a (partial) )Form prism side surface.
  • the lateral wall above the raised floor section in the horizontal cross section essentially has the shape of an at least 5-sided polygon, a circle or an ellipse or a shape approximating these geometric shapes.
  • the bottom of the glass melting tank has at least one step and is therefore referred to above as "stepped".
  • the step is formed here by the raised floor section, the transition wall and the homogenizing floor section, with the step running along at least 70% of the circumference of the tub interior (ie on the side wall).
  • the bottom of the glass melting tank thus has the homogenization bottom section, which is surrounded by the raised bottom section. It is very advantageous for the glass quality if the step runs along a larger portion of the circumference of the tub interior, for example along at least 80% of the circumference, or along the entire circumference of the tub interior and thus surrounds the entire homogenization bottom section. In the latter case the stage is not interrupted.
  • the step may be formed as a single, uninterrupted step or formed in two or more than two peripheral sections, particularly if the glass melting tank has more than one exit opening for withdrawing the molten glass.
  • the stage can be interrupted/divided, for example, by a channel to the exit opening, which connects the homogenization space with an exit opening located further out.
  • the tub interior essentially has the shape of two body-shaped spaces arranged one above the other, with each of the two spaces having the shape of a prism (horizontal cross-section corresponds to a polygon) or a cylinder (horizontal cross-section corresponds to a circle or an ellipse) or one of these Shapes can have an approximate shape.
  • the shapes of these spaces can be combined in any way and thus adapted to the respective other conditions of the glass melting tank, for example the melting and refining space can have the shape of a prism and the homogenization space can have the shape of a cylinder or vice versa.
  • the combination of similar shapes (cylinder - cylinder or prism - prism) is also possible.
  • the side wall and the transition wall are trained accordingly.
  • the areas of the exit opening(s) and the channel(s) upstream of these (in the direction of flow of the glass melt) are not taken into account in this consideration (dividing the tub interior into two rooms).
  • the space (or volume) formed further up, above the raised floor section by the tub interior, is the melting and refining space and has an average diameter D (measured from the hot space side of the side wall).
  • the raised bottom section thus defines a level above which the melting and refining space is formed by the tub interior.
  • the average diameter D of the tub interior above the raised floor section ie the average diameter of the melting and refining space
  • the maximum average diameter D of the tub interior above the raised floor section can be, for example, 16 m.
  • the space (or volume) formed for the glass melt directly below the level of the raised floor section is the homogenization space, which is bounded laterally by the transition wall, upwards by the melting and refining space and downwards by the homogenization floor section and whose upper end is approximately at the Height of the raised floor section is.
  • the homogenization space has an average diameter d, where d ⁇ D/2.
  • the average diameter d of the homogenization space is at least 1.6 m and a maximum of 8 m.
  • the width B is less than or equal to D/3 in order to create enough volume for the good homogenization of the glass melt through a sufficiently large lateral expansion of the homogenization space.
  • the above definition also means that the two rooms (melting and refining room and homogenization room) are arranged essentially concentrically, that is, the two vertical axes of these rooms lie one above the other or parallel, with the axes only being a small distance apart in the latter case in the horizontal direction, ie a maximum distance of 0.5 m.
  • the average diameter d is determined as the average diameter in the area of the homogenization space, ie as the average diameter of the glass melting tank below the raised bottom section.
  • the homogenization room is arranged directly, ie directly below the melting and refining room. After being introduced into the melting and refining room, preferably from above, the starting materials are melted and refined and then reach the homogenization room immediately below.
  • the homogenization space can also have the shape of a circle, an ellipse or an at least 3-sided polygon, for example an at least 5-sided polygon or an at least 6-sided polygon.
  • the raised floor section may not have the same width everywhere in the horizontal direction. This results from the shapes of the melting and refining room and the homogenization room.
  • Each of the two spaces can take the form of a rotationally symmetrical body, with rotational symmetry meaning that the respective body is imaged on itself by rotating through certain, predetermined angles about the longitudinal axis.
  • the rotationally symmetrical body is a substantially straight body, since a space in the form of a straight body is more cost-effective when realizing such a glass melting tank.
  • the tub interior In the vertical direction, the tub interior has a predetermined height, the height being measured from the bottom of the homogenizing base section to the top edge of the side wall.
  • the vertical height of the tub interior is a maximum of 3.5 m, since deeper tubs would endanger the operational safety of the system with regard to the temperature-related length change behavior of the refractory material forming the side wall and the transition wall and the vitrostatic pressure of the glass.
  • the height difference h between the raised floor section and the homogenization floor section is at least 0.5 m. This creates a sufficiently large homogenization space in the vertical direction and also in terms of volume (taking into account the expansion in the horizontal direction), so that good glass quality can be achieved.
  • the height difference mentioned also forms the vertical height of the homogenization space.
  • the difference in height (regardless of any sloping design of the transition wall) is measured in the vertical direction based on the surface of the glass melt.
  • the height difference between the raised floor section and the homogenizing floor section is a maximum of 2.7 m in one exemplary embodiment.
  • the height of the glass melt in the production operating state in the tub interior is also referred to as the glass level depth.
  • the glass depth only includes the height of the melt, but not the covering of cold raw material mixture and/or shards arranged above the melt.
  • the glass level depth is a value assigned to the interior of the glass melting tank and can, for example, be measured indirectly through the bath depth in the riser, which is located after the exit opening and the passage channel Flow direction connects to the glass melting tank.
  • the glass stand depth T can be at least 0.8 m and a maximum of 2.7 m, while in the area of the homogenizing floor section the glass stand depth can be at least 1.3 m and a maximum of 3.2 m.
  • the transition wall may extend vertically with respect to the surface of the glass melt.
  • the transition wall can run at a small angle to this vertical, for example at a maximum angle of 30 ° to this vertical.
  • the slope of the transition wall can be selected such that the diameter of the homogenization space is larger at the top than at the bottom, in the area of the homogenization bottom section, or vice versa.
  • the surface of the raised bottom section runs parallel to the surface of the glass melt; in one embodiment, the surface of the raised bottom section can run obliquely, for example in such a way that the glass stand depth above the raised bottom section increases radially towards the center of the glass melting tank, i.e The middle of the glass melting tank is designed to slope down.
  • the electrodes that are active in the production operating state and protrude into the glass melt are arranged in two groups in the glass melting tank according to the invention.
  • a first group of electrodes are used as a top electrode, bottom electrode and/or side electrode in an area adjacent to the side wall and a second group of electrodes are used as a bottom electrode in an area adjacent to the transition wall in the production operating state.
  • These two groups are located in the area of the raised floor section, ie in or above the raised floor section.
  • no active electrodes in the production operating state are arranged in the homogenization space. This means that in the production operating state, which is in the homogenization space The glass melt present is not heated.
  • the energy input (ie the heat input) into the glass melt occurs only in the area of the melting and refining space above the level of the raised floor section.
  • the electrodes of the first group and the electrodes of the second group are spaced apart from one another, for example in the radial direction, the distance between the electrodes being chosen such that it takes into account the width of the raised bottom section and a minimum distance (for top and bottom electrodes) from the side wall in the first group and a minimum distance from the transition wall is as large as possible.
  • no further electrodes, which heat the glass melt in the production operating state are provided between these two groups.
  • at least one further group of electrodes can be provided between these two groups, which supply thermal energy to the glass melt in the production operating state, this further group also being arranged in the melting and refining room and heating the glass melt above the raised floor section.
  • the glass throughput is in the range between 80 t/day and 450 t/day.
  • This throughput is achieved in that, on the one hand, in the area of the melting and refining room above the raised bottom section due to the two spaced-apart electrode groups arranged there and the resulting effects Flows in the glass melt ensure good melting of the starting materials (batch and/or shards), which are preferably placed from above, and good refining (ie driving out the bubbles) of the glass melt is achieved.
  • the distance between the electrodes of the first electrode group and the electrodes of the second electrode group results in the formation of a strong, easily controllable flow in the glass melt in the area of the melting and refining room.
  • the distance between the electrodes of the first group and the nearest electrodes of the second group or the distance between the oppositely arranged electrodes of the second group is approximately comparable, so that there is also a corresponding, sufficient glass melt in the central area of the glass melt arranged in the melting and refining room Flow dynamics in the glass melting tank are caused, which differ little from the flow in the outside area of the melting and refining room (see explanations below for Fig. 2b and 2c).
  • the flows due to the essentially vertical arrangement of the bottom electrodes, the flows have a significant vertical component, which promotes good melting and refining in the melting and refining space.
  • the glass melt is provided with sufficient volume in the homogenization room, which is located below the melting and refining room, so that the glass melt is homogenized and calmed to the extent required for good gas quality in such a way that solid starting materials or bubbles escape directly into an exit opening is prevented. This is achieved in particular because there is no energy input in the homogenization room in the production operating state, since the glass melt is not heated there by means of electrodes.
  • each convection band rotating in opposite directions (based on a vertical section) are formed in the glass melt, each convection band having a large vertical, upward component in an area near the respective electrode and has a large vertical downward component in a central region between opposing electrodes. Between an area near an electrode and the adjacent central area, each convection band has a large horizontal component.
  • the convection bands are shown in FIGS.
  • the convection bands ensure good mixing of the starting materials, which are preferably applied from above, and promote the complete dissolution of the harder-to-melt components of the starting materials. This convection takes place in the melting and refining room.
  • the glass melt in the homogenization space in the production operating state, there is no energy input through electrodes, so that the glass melt there has a significantly smaller flow velocity, for example at least an order of magnitude smaller, with the exception of an upper transition section of the homogenization space, which is in the immediate vicinity and in the transition to the melting and Lautering room is arranged. In this transition section, the glass melt flows at a slightly higher speed.
  • the height of this transition section is not greater than 0.25 xh, for example not greater than 0.15 xh, with the transition section on the sides (ie seen in the radial direction) of the homogenization space being a lower one Height (measured vertically from the level of the raised floor section) than in the central area.
  • the glass melt is characterized by the fact that in the points of this area the vertical component of the Speed of the glass flow, ie the average sinking speed of the glass melt in the direction of the outlet opening, is approximately in the order of magnitude of the buoyancy speed of the gas bubbles enclosed in the melt or is smaller than this buoyancy speed of the gas bubbles.
  • the main section has a greater height on the sides (ie seen in the radial direction) of the homogenization space than in the central area.
  • the respective sinking speed and the respective buoyancy-related speed are related to the corresponding glass chemistry (ie the respective composition of the glass melt or the respective type of glass (borosilicate glass, water glass, container glass, fiber glass)).
  • the glass melt is calmed down, as described above, and any gas bubbles that may still be present are not pulled downwards by the sinking glass melt towards the outlet opening, but instead migrate upwards into the melting and refining room due to their buoyancy.
  • the vertical height of the homogenization space h is dimensioned such that the outlet opening is vertically at a sufficient distance from the melting and refining space in order to provide the gas bubbles with enough time and volume to rise.
  • the outlet opening is arranged such that, when the glass melting tank is new, its upper edge has a vertical distance from the level of the raised bottom section that is greater than x h.
  • the electrodes of the first group are arranged in particular in an area of the melting and refining room, so that they have a maximum distance (in the horizontal direction) of 800 mm from the hot room side of the side wall.
  • the electrodes of the first group can be designed as top electrodes and/or side electrodes and/or bottom electrodes.
  • As a top electrode the respective electrode protrudes from the surface of the glass melt into it, as a side electrode, the respective electrode protrudes from the side wall into the glass melt, and as a bottom electrode, the respective electrode protrudes from the raised bottom section into the glass melt.
  • the top electrode can, for example, have a minimum (horizontal) distance from the side wall of 150 mm, while the bottom electrode can have a minimum (horizontal) distance from the side wall of 150 mm (in each case based on the hot room side of the side wall).
  • the side electrode can have a distance from the raised floor section of a maximum of 2.5 m and/or at least 200 mm, the distance also depending on the glass level depth above the raised floor section.
  • the electrodes of the second group are, for example, designed as floor electrodes and have, for example, a minimum distance of 500 mm from the edge of the raised floor section at which the transition wall begins (hereinafter also referred to as the inner edge). They also have a specified distance from the electrodes of the first group. Consequently, the horizontal diameter of the arrangement formed by the second group of electrodes is larger than the diameter d of the homogenization space, for example larger by at least 1 m.
  • the electrodes within the respective group can be individually or as a pair along a line that is parallel to a horizontal cross-sectional line of the side wall (for the first group of electrodes) or the Transition wall (for the second group of electrodes) must be arranged equally distributed/equidistant.
  • the electrodes of the first group can be divided into subgroups of three, for example, as explained below individual electrodes or three pairs of electrodes which have a smaller distance in the direction along the line. The distance between the outer two of the three electrodes/electrode pairs is approximately comparable to the distance between the middle electrode/electrode pair and an opposite electrode/electrode pair of the second group.
  • all electrodes of the first group have the same distance (in the horizontal direction) from the side wall (if these are designed as top or bottom electrodes) and / or all electrodes in the second group have the same distance (in the horizontal direction) from the transition wall.
  • the distance from the side wall or the transition wall can vary within the respective group, which can also be caused by the specific shape of the side wall or the transition wall.
  • the electrodes are arranged in such a way that the volume of the melting and refining chamber is heated as a whole and that no dead zone is created.
  • a dead zone is avoided.
  • the convection introduced by the electrodes of the second group produces convection bands which extend over the central region of the melting and refining space.
  • the above-described advantageous spatial arrangement of the electrodes of the first group near the side wall and the electrodes of the second group near the transition wall leads to a flow dynamic in the melting and/or refining space that is particularly uniform in the horizontal direction and can therefore be set to be comparatively stable can.
  • the interior of the tub represents the space intended for the melting of the added raw material mixture and/or the supplied shards, the refining of the glass melt and its homogenization. As already explained above, it can be divided into a melting and refining space at the top and into one below subsequent homogenization room can be divided.
  • the tub interior therefore has a compact shape that is also easily accessible from the outside.
  • the specified shape is usually produced by palisade parts made of fireproof material, which are placed and fastened next to and/or one above the other.
  • the refractory material is, for example, inorganic, non-metallic materials (ceramic, glass, glass ceramic, mineral fibers) and can include, for example, the oxides silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, zirconium oxides, chromium oxide.
  • carbon and silicon carbide can be used as components.
  • melt-cast AZS aluminates, zirconates, silicates, also aluminum, zirconium and silicon oxides
  • the refractory material can have at least one coating on the hot room side, for example made of platinum or a platinum alloy. With or without the specified coating, the refractory material can consist of one layer, at least two or more than two layers with different compositions, e.g. B. with different zirconium content.
  • the cold space sides of the side wall and the transition wall of the glass melting tank, which each face away from the tank interior, can run essentially parallel to the respective hot space side.
  • the cold room sides can be at least partially or completely provided with insulation.
  • a collar can be arranged directly on the transition wall in the area of the raised floor section, which is at least 50 mm high and/or at least 50 mm wide.
  • the height is given as the height above the raised floor section.
  • the width is the extent of the collar in the horizontal direction.
  • the collar begins at the transition wall and represents a protrusion that protrudes vertically from the raised bottom section.
  • the end wall of the collar (threshold) opposite the transition wall is arranged radially further inside the tank interior than the electrodes of the second group. The collar causes an additional mechanical separation of the moving zone in the melting and refining chamber from the calmed zone in the homogenization chamber.
  • the glass melting tank is set up in such a way that it works according to the cold top principle. This means that the raw material mixture and/or shards are fed from above in the direction of the surface of the glass melt, which in the production operating state is preferably completely covered for most of the time. In one embodiment, in the production operating state, the diameter or the area of the surface of the glass melt covered with raw material mixture and/or shards is larger than the diameter d or the cross-sectional area of the homogenization chamber.
  • the heating of the glass melt in the production operating state is, as shown above, carried out exclusively by means of electrodes that protrude from above into the surface of the glass melt (top electrodes), protrude from the raised bottom section into the glass melt (bottom electrodes) or protrude from the side wall (side electrodes) into the glass melt, and only into the glass melt arranged in the melting and refining chamber.
  • at least one burner can be provided for fossil heating (e.g. for tempering the glass melting tank), which, however, is not used in production operation.
  • the tub interior is covered at the top by a ceiling, which almost completely seals off the tub interior in a dust-tight manner.
  • the tub interior is completely dust-tight in such a way that in the central area of the tub interior above the glass melt in the production operating state is formed with a negative pressure relative to a location in the surroundings of the glass melting tank, at which exhaust gas derived from the tank interior is released.
  • the dust-tight seal means that practically no dust that comes from the inside of the tank gets into the area around the glass melting tank.
  • heat losses can be significantly reduced through sealing.
  • the openings for the electrodes and any existing burners are sealed dust-tight during normal operation, but this is not guaranteed when changing the electrodes.
  • the openings for feeding the mixture and/or the shards are sealed in a gas-tight manner.
  • a ventilation device is provided (eg in a side wall) through which gas produced during melting can be removed.
  • the gas is filtered using appropriate filters (e.g. with regard to toxic gases and dust) in such a way that the relevant environmental regulations are met.
  • the exhaust gas is released into the environment.
  • the ceiling is designed as a rotating ceiling, which essentially has the shape of a disk and which is preferably designed as a suspended rotating ceiling.
  • a rotating blanket in the form specified above allows the tub interior to be easily covered upwards, so that heat loss and the release of exhaust gases and/or dust can be avoided or reduced.
  • the rotating ceiling which is designed to be rotatable over at least 90 °, preferably over at least 180 °, allows a simple, uniform and easily controlled supply of raw material mixtures and / or shards to the glass melt.
  • the side wall, the transition wall and the bottom of the glass melting tank can be at least partially supported by an external steel frame arranged on a cold room side.
  • the external steel frame supports the side wall, the transition wall and the bottom (ie the raised floor section and the homogenization floor section).
  • the outer steel frame can also have a ring-shaped rail element on its upper side.
  • the respective rail element serves to support and guide the rotating ceiling, whereby the rotating ceiling has at least three corresponding wheels or pairs of wheels that roll along the respective rail element.
  • the sealing of the glass melting tank in the area of the side wall is carried out by means of an apron (collar) that projects vertically downwards from the rotating ceiling and engages in a guide that contains a sealing material, e.g. sand (also referred to as a sand pocket).
  • apron collar
  • the guide can be arranged on the top of the external steel frame in an approximately horizontal direction next to the respective rail element.
  • the glass melting tank is designed in such a way that the raw material mixture and/or shards are fed into the glass melting tank from above through at least one corresponding, dust-tight opening in the ceiling in such a way that the raw material mixture and/or the shards are continuously applied over a large area to the surface the glass melt is/are placed, for example in the form of one or more annular strips.
  • large-scale application it is meant that raw material mixtures and/or glass shards are placed on at least 40% of the surface of the glass melt, which ⁇ ) are distributed over the entire surface of the glass melt due to the cones of material that form and the movement of the covering on the glass melt.
  • the feed device and the rotating blanket are designed in such a way that the feed of raw material mixtures and/or shards into the glass melting tank through a large number of dust-tight sealed openings in the rotating ceiling.
  • the feed can in particular take place through two or more openings, for example arranged next to one another in the radial direction of the rotating ceiling, which results in a more even distribution of the raw material mixture and/or the shards on the surface of the glass melt.
  • At least two groups of openings which lie next to one another in the radial direction, can be provided for the supply of raw material mixtures and/or shards, which further evens out the distribution and, if necessary, reduces the angle of rotation required when rotating the rotating ceiling.
  • the feed device can, for example, be designed in such a way that at least one stationary storage container for raw material mixtures and/or shards is provided above the glass melting tank, from which the raw material mixture and/or shards are fed to at least one storage container movable with the rotating ceiling at appropriately coordinated times by means of a metering device.
  • the raw material mixture and/or shards can be supplied in sufficient quantities if the movable storage container is located under the stationary storage container along the rotational movement of the rotating ceiling.
  • a flexible feed pipe can be provided, which connects the output of the metering device to the inlet of the storage container that is movable with the rotating blanket during the rotation of the rotating blanket.
  • the raw material mixture and/or shards are then further distributed to the openings in the rotating ceiling, for example by means of a further transport and/or metering device (e.g. a vibrating trough or screw).
  • the openings of one group are arranged offset in the radial direction from the openings of the other group, so that the surface of the glass melt can be evenly provided with the raw material mixture/broken glass supplied.
  • the transport and/or metering device can, for example, be designed in such a way that the at least one opening located radially further inwards has a smaller amount of raw material mixture and / or shards than the at least one opening located radially further out, since the area on the surface of the glass melt to be covered by the respective opening when the rotating ceiling rotates differs accordingly.
  • the flow direction of the glass is from top to bottom (vertical), ie from the surface of the glass melt towards the homogenization bottom section of the tub interior, with at least one outlet opening through which the molten glass is drawn off in the area of Homogenization base section, the lower end of the transition wall and / or the lower end of the side wall is arranged.
  • the outlet opening can be located in the vertical direction at the level of the lower end of the transition wall or below, ie approximately at the level of the homogenization base section.
  • the lower edge of the outlet opening can, for example, lie at the height of the homogenization base section or below in the vertical direction.
  • one, two or three outlet openings lying next to one another or opposite one another are provided at the lower end of the transition wall and/or at the lower end of the side wall.
  • a corresponding depression/notch can be provided in the homogenization base section, for example with a width of at least 400 mm, which extends towards the outlet opening.
  • the outlet opening is at least partially or completely below the vertical height of the homogenizing base section.
  • the side wall extends in the area of the outlet opening up to the homogenization base section.
  • the raised bottom section is interrupted in an area running radially to the axis of the melting and refining space/homogenization space.
  • a radially extending channel is provided upstream of the outlet opening in the flow direction of the glass melt runs essentially in the radial direction from the homogenizing base section to the (pulled-down) side wall.
  • the channel has at least a width that corresponds to the width of the outlet opening, for example at least 400 mm.
  • the vertical height of the outlet opening when new is less than x h.
  • the maximum width that the channel can assume in one embodiment is the maximum diameter of the homogenization space.
  • the outlet openings are arranged opposite each other (corresponds to a distance of 180 0 based on the circumference of the raised bottom section or the homogenizing section, depending on where the outlet opening is provided - in the radial direction), when three If outlet openings are used, they are at a distance of 120 °, for example.
  • each electrode of the first group can be designed as a top electrode such that, in the production operating state, it projects vertically in relation to the surface of the glass melt or at a small angle to this vertical direction, e.g. a maximum of 30°, preferably between 50 and 20°, obliquely from above, i.e. from the surface of the glass melt, into the glass melt and heats the glass melt from above.
  • the top electrode can additionally be designed so that it can be pivoted in and out of the interior of the tank. This makes it easy to replace or replace each electrode.
  • the electrodes arranged in/on the side wall are accessible from the outside.
  • Each top electrode has a corresponding, pivotable holder.
  • each electrode of the second group can be designed as a bottom electrode such that in the production operating state it projects vertically in relation to the surface of the glass melt or at a small angle to this vertical direction, e.g. a maximum of 30°, preferably between 5° and 20°, obliquely from below, ie from the raised bottom section, into the glass melt and heats the glass melt from below.
  • the bottom electrode can also be designed to be pushed into the interior of the tank. This allows each electrode to be easily replaced. The electrodes arranged in the raised bottom section are accessible from below.
  • At least one step and/or at least one recess is provided on or in the side wall on the respective hot space side.
  • the at least one recess in/on the side wall of the glass melting tank can be provided, for example, for the arrangement or the swinging in and/or out of the at least one top electrode.
  • a step arranged, for example, above the side wall can be designed in such a way that it reduces or increases the ring width of the tank interior compared to below the step.
  • the glass melting tank is provided with a large number of electrodes for heating the glass melt, the required number of electrodes heating the glass melt in the production operating state and their energy supply being determined on the basis of the melting and refining energy required for a given glass throughput.
  • the total number of electrodes can be, for example, 18, 24, 36 or 42, whereby the first group and the second group can have a different or the same number of electrodes.
  • the resulting average current density on the surface of the respective electrode which should not exceed the value of 3 A/cm 2 , can be used as a boundary condition parameter.
  • a current carrying capacity of the electrode holder system of around 3,600 A should not be exceeded.
  • the electrodes are arranged, for example, on at least two circumferential, concentric circles or circular lines (viewed in horizontal cross section) and interconnected in such a way that a voltage of 500 V (for safety reasons) and a current of 3,600 A is not exceeded.
  • the outer (larger) circle/line is located on the side wall or at a radial distance of 150 to 800 mm, typically 330 mm, from the hot room side of the side wall, while the inner (smaller) circle/line is at a distance of at least 500 mm, typically 750 mm, from the transition wall in each case on the raised floor section and at a predetermined distance from the circle/circular line of the first group of electrodes.
  • the electrodes can be arranged individually or in pairs, evenly distributed/equidistant along the circumference on the respective circle/line.
  • Electrode/electrode pair In order to achieve the most uniform possible current distribution and thus even wear on the electrodes, three electrodes or pairs of electrodes lying next to one another on the line or circle, as explained above, can be placed on the outer circle at a smaller distance from one another than from the closest one Electrode/electrode pair may be provided.
  • the distance between the outer two of the three electrodes/electrode pairs is advantageously approximately comparable to the distance between the middle electrode/electrode pair and an opposite electrode/electrode pair of the second group.
  • a good distribution of the flows in the melting and refining space can be achieved if the ratio of the diameter DEG2 of the circle or the circular line of the second group of electrodes to the diameter DEG1 of the circle or circular line of the first group of electrodes DEG2/DEG1 is in the range between 0.45 and 0.7. This applies in particular if the electrodes of the first group are designed as top or bottom electrodes.
  • an installation of two electrodes arranged close to each other and electrically connected in parallel can be used. This results in a high number of electrodes.
  • a single electrode can be used for each pair of electrodes.
  • an energy supply device which implements a circuit that causes a uniform, symmetrical load on the electrodes.
  • Suitable electrical circuits map the arrangement of the pointers in the electrical pointer diagram to a geometrically similar arrangement of the electrodes in the respective new glass melting tank.
  • the number and arrangement of the pointers in the electrical pointer diagram results from the number and configuration of transformers provided in the power supply device.
  • Open three-phase system the number of connected electrodes is a multiple of 6.
  • the open three-phase system offers advantages in terms of lower stress on the melting electrodes and is therefore preferred.
  • the above object is also achieved by a glass melting system with a glass melting tank described above, the glass melting system further having a supply system for supplying raw material mixtures and/or glass shards and an energy supply device for the plurality of electrodes, the energy supply device being connected to each electrode.
  • the glass melting system has the advantages explained above for the glass melting tank.
  • the hot room side of the side wall above a raised floor section essentially has an at least 5-sided polygon, a circle or forms an ellipse, with the bottom being at least along 70% of the circumference of the tub interior, and a central, surrounded by the elevated floor portion and lower in relation to this homogenizing floor portion, wherein the elevated floor portion extends from the hot room side of the side wall laterally in the direction of the tub interior and has a width , which is greater than or equal to 0.25 x D, where D is the average diameter of the tub interior above the raised bottom section, wherein in the transition from the raised bottom section to the homogenization bottom section there is a perpendicular or almost perpendicular with respect to the surface of the glass melt running transition wall is formed, as well
  • the glass melting tank shown above can be constructed in a simple and cost-effective manner.
  • the palisade elements can be arranged next to one another and, if necessary, one above the other.
  • the palisade elements are preferably fixed using the external steel frame described above.
  • the materials that can be used for the palisade elements are also already specified above.
  • the glass melting tank described above is suitable for glass throughput quantities in the range of 80 t/day to 450 t/day.
  • the following parameters of the glass melting tank described above and the parameters of the following exemplary embodiments were also determined using simulations and various tests.
  • Computerized Fluid Dynamics (CFD) was used in particular as a simulation method. With this method, for example, flow and temperature profiles can be calculated and, from this, quality indices known to those skilled in the art of the resulting, simulated glass melt can be determined.
  • the average diameter D of the glass melting tank in relation to the hot room side of the side wall above the raised floor section can be, for example, between 5 m and 16 m.
  • the average diameter d in relation to the hot room side of the homogenization room between opposite areas of the transition wall can be, for example, between 2.5 m and 8 m.
  • the glass stand depth T up to the homogenization base section can be, for example, 1.3 m to 3.2 m. Accordingly, the tub interior has a greater height (in the vertical direction) H compared to the glass stand depth T.
  • the melting area surface of the glass melt in the production operating state
  • the novel glass melting tank described above can be used for soda-lime glasses, borosilicate glasses, fiber glasses or other types of glasses.
  • the invention is explained below using exemplary embodiments and with reference to the figures. All described and/or illustrated features, individually or in any combination, form the subject matter of the invention, regardless of their summary in the claims or their references. It shows schematically:
  • FIG. 1 shows a first exemplary embodiment of a glass melting tank and a glass melting system in a perspective view from the side, partially cut away,
  • Fig. 2, 2a-4 the glass melting tank according to Fig. 1 in three vertical
  • Fig. 5-6 the glass melting tank and feeding system according to Fig. 1 in a view from above (Fig. 5) and in a view from below (Fig. 6),
  • FIG. 7-8 a second embodiment of a glass melting tank in a vertical cross section (Fig. 7) and in a horizontal cross section (Fig. 8),
  • FIG. 9-10 a third embodiment of a glass melting tank in a vertical cross section (Fig. 9) and in a horizontal cross section (Fig. 10),
  • Fig. 11 shows a fourth embodiment of a glass melting tank Feed system in a perspective view from the side, partially cut open,
  • FIG. 15-16 a fifth embodiment of a glass melting tank in a vertical cross section (Fig. 15) and in a horizontal cross section (Fig. 16),
  • FIG. 17 shows a sixth exemplary embodiment of a glass melting tank with a feed system in a perspective view from the side, partially cut away,
  • FIG. 22 shows a seventh embodiment of a glass melting tank with a feed system in a perspective view from the side, partially cut away,
  • Fig. 23-24 shows the glass melting tank according to Fig. 22 in a vertical cross section (Fig. 23) and in a horizontal cross section (Fig. 24),
  • FIG. 27 shows an eighth embodiment of a glass melting tank with a feed system in a perspective view from the side, partially cut away,
  • Fig. 28-30 a section of the side wall of the embodiment according to Fig. 1 with top electrode and electrode holder in a perspective view from the side with the electrode in the production operating state (Fig. 28) and in the partially or completely swung out state (Fig. 29 and 30),
  • FIG. 31-32 an area of the raised bottom section of the exemplary embodiment according to FIG. 1 with bottom electrode and electrode holder in a perspective view from the side with recessed electrode (Fig. 31) and electrode in production operating state (Fig. 32),
  • FIG. 34 shows a horizontal cross section of the glass melting tank according to FIG. 1, which illustrates the connection of the electrodes in this exemplary embodiment.
  • the exemplary embodiments of a glass melting tank or a glass melting system described below contain top electrodes as electrodes of the first group, which are arranged in an area adjacent to the side wall.
  • the exemplary embodiments can also be implemented analogously with bottom electrodes that protrude from the raised bottom section into the glass melt or with side electrodes that protrude from the side wall in a horizontal direction into the glass melt. Analogous to the top electrodes, the bottom electrodes have a predetermined distance from the hot room side of the side wall.
  • the first embodiment of a glass melting system with a glass melting tank 10 shown in Fig. 1 to 6, 28 to 32 and 34 is shown partially cut open in Fig. 1 so that the tank interior 11 is visible.
  • the tank interior 11 in which the glass melt 12 is arranged is laterally delimited by a side wall 13.
  • a raised floor section 14 and a homogenization floor section 15 are provided, which together delimit the tank interior 11 from below.
  • the raised floor section 14 and the homogenization floor section 15 are connected to one another by a transition wall 16 running vertically (perpendicular to the surface of the glass melt 12), so that a step is formed in the glass melting tank 10.
  • the glass melting tank 10 works according to the cold top principle and therefore has a covering 12a (see Fig.
  • the glass melt 12 made of unmelted raw material mixture and/or cullet, which covers the majority of the surface of the glass melt 12.
  • the raw material mixture and/or the cullet are, as described in more detail below, fed to the glass melt 12 from above through the dust-free sealed cover of the tank interior 11, which is designed as a suspended rotating ceiling 19.
  • the tank interior 11 is made up of the cylindrical melting and refining chamber 11a arranged above the raised base section 14 and the cylindrically shaped homogenization chamber 11b adjoining it and arranged concentrically to the melting and refining chamber 11a, the homogenization chamber 11b being delimited laterally by the transition wall 16 and below by the homogenization base section 15.
  • Fig. 2a which corresponds to the cross section shown in Fig. 2, the two sub-chambers 11a, 11b of the tank interior 11 are illustrated by different hatching.
  • the position of the cross sections according to Fig. 2 and 2a is shown in Fig. 4 by means of a dashed line S1
  • the position of the cross section according to Fig. 2b and 2c is shown in Fig. 4 by means of a dash-dotted line S2.
  • the side wall 13 has a circular shape (based on a horizontal cross section) above the raised bottom section 14 and a vertical height H, so that the melting and refining space 11a is essentially cylindrical in shape.
  • the average diameter D above the raised floor section between opposite hot room sides of the side wall 13 is 14 m in this exemplary embodiment.
  • the raised floor section 14 has a width B of 4.2 m, so that the diameter d of the homogenization space or the distance between opposite lying hot room sides of the transition wall 16 is approximately 5.6 m.
  • the height difference h between the circular homogenizing floor section 15 and the raised floor section 14 running around the homogenizing floor section 15 is approximately 1.1 m (see FIG. 2).
  • an outlet opening 13a is provided through which the molten glass is withdrawn in order to then be processed into container glass, for example.
  • the side wall 13 extends in the area of the outlet opening 13a to the homogenization base section and is connected to the homogenization space 11b via a channel 11c extending along the radial direction. In the area of the channel 11c is the raised floor section
  • the outlet opening 13a is at the level of the homogenizing base section 15, so that the channel 11c runs straight from this towards the outlet opening 13a.
  • the outlet opening 13a is followed by the passage channel 21, the riser 22 and the working trough 23 in the flow direction of the glass melt.
  • the glass melting tank 10 has two groups of electrodes.
  • a first group of electrodes 17 (here: 24 electrodes) are arranged at a distance of approximately 250 mm to 550 mm next to the side wall 13 and are designed as top electrodes. They protrude into the glass melt 12 from above. These electrodes are also referred to below as external electrodes 17.
  • a second group of electrodes 18 is provided, which are arranged on the raised floor section 14, at a distance of approximately 600 mm to 800 mm from the transition wall and are designed as floor electrodes. They project vertically upwards from the raised base section 14 or into the glass melt 12 at a slight angle to the vertical.
  • the electrodes of the second group are also referred to as internal electrodes 18.
  • the two groups have a distance that is, for example, between 2.85 m and 3.35 m.
  • the distance between opposing internal electrodes 18 is, for example, 6.8 m.
  • each outer electrode 17, as shown in more detail in FIG. 28, protrudes through a wall 13 above the side wall 13 arranged opening 13d into the tub interior 11 and from above into the glass melt 12.
  • each outer electrode 17, as shown in FIGS. 29 to 30, is designed to be pivotable between a first position shown in FIG. 28 and a second position sketched in FIG. 30. In the first position, the electrode 17 is in the working state in which the electrode supplies thermal energy to the glass melt 12 in the production operating state due to the Joule effect. In the second position of the electrode 17, it is completely moved out of the tub interior 11 and can be serviced, for example. The position shown in FIG. 29 symbolizes the movement of the electrode 17 out of the tub interior 11.
  • each outer electrode has a holder 17a with which the electrode can be pivoted and which fastens the electrode to an outer steel frame 36 arranged on the outside of the side wall 13.
  • each electrode is arranged slightly inclined (eg, at an angle of 5° to 20°) to the vertical direction (see Fig. 28), which makes it easier to swing the electrode in and out.
  • each opening 13d is sealed in a dust-tight manner in the production operating state.
  • this exemplary embodiment has twelve inner electrodes 18 and twenty-four outer electrodes 17, which are each arranged in pairs and otherwise evenly distributed along/next to the side wall 13 or the transition wall 16.
  • the outer electrodes can also be arranged in groups of three pairs each, each of which is at a smaller distance from the neighboring pair than if the pairs were evenly distributed over the entire circumference. No electrodes are provided in the area of the channel 11c.
  • the inner electrodes 18 are designed as bottom electrodes, which in the production operating state protrude upwards from the raised bottom section 14 into the glass melt 12 in the vertical direction, as shown in more detail in FIG. 32.
  • Each electrode 18 is, as shown in Figs. 31 and 32, Designed to be movable so that it can be replaced or adjusted if it wears out.
  • the electrode is inserted into the tub interior 11 through a hole 14a in the bottom section 14, which is closed by an electrode block 12b made of particularly high-strength refractory material (eg AZS with a high zirconium content of at least 41%).
  • the electrode 18 has a hollow cylindrical insulation and cooling unit 18a, which is cooled, for example, with water.
  • a holder 18b is provided, with which the electrode 18 is fastened to the cold room side of the raised floor section 14.
  • the holder 18b is also designed in such a way that it enables manual displacement of the electrode 18 in the vertical direction along a guide rail running parallel to the electrode. This allows the electrode 18 to be tracked in a defined manner.
  • Fig. 31 shows the electrode 18 in a state in which the electrode 18 is retracted.
  • the arrangement of the electrodes and the dimensioning of the raised base section 14, the transition wall 16 and the homogenization base section 15 causes the formation of convection bands KB1 to KB6 in the melting and refining space 11a between opposite electrodes, so that good melting of the starting materials and good refining is achieved.
  • the convection bands lying between two electrodes and rotating in opposite directions are the convection bands KB1 and KB2, KB3 and KB4 as well as KB5 and KB6.
  • Another two convection bands KB7 and KB8 are formed between the electrodes 17 and the side wall 13.
  • the convection bands KB1 to KB8 are illustrated in the simulation shown in Fig.
  • the glass melting tank 10' used for the simulation does not correspond exactly to the glass melting tank 10 shown in FIGS. 1, 2, 2a, 3 and 4, because in the variant of FIGS Electrodes 17 'are directly opposite the respective inner electrodes 18 of the variant of FIGS. 1, 2, 2a, 3 and 4 arranged. Furthermore, it should be noted about the convection bands KB3, KB4 and KB5 that these partially extend into the plane of the drawing and are therefore not so clearly visible in the simulation data shown in Fig. 2b.
  • the direction of the arrows represents the direction of flow of the glass melt and the length of the arrows represents the amount of speed.
  • the convection is very large in the form of the convection bands KB1 to KB8 in the melting and refining area 11a. It can also be seen from the simulation shown in FIG. 2b that, in contrast, a small flow can be observed in the homogenization space 11b (or in its main section located below a transition section).
  • the vertical component of the flow velocity of the glass melt towards the outlet opening 13a is smaller than or is in the order of magnitude of the buoyancy-related velocity of the gas bubbles enclosed in the glass melt.
  • the electrodes 17 of the first group are arranged at a distance of 0.75 m from the hot room side of the side wall 13 and the electrodes 18 of the second group are arranged at a distance of 0.6 m from the transition wall 16 .
  • the glass type used for the simulation was soda-lime glass with a glass density (under production conditions) of 2.4 t/m 3 .
  • a feed device has a stationary storage container, not shown, with a metering device.
  • a storage container 24 rotating with the rotating ceiling 19 is provided on each side. From each storage container 24 rotating with the rotating ceiling 19, the raw material mixture and / or shards reach a screw or vibrating trough 27 and are transported through this via further rotating storage containers 28 through a continuous opening 19a by means of small vibrating troughs into the tub interior 11 and onto the surface the glass melt 12 is transported.
  • each opening 19a of the first group, which is connected via a screw or vibrating trough 27, is arranged offset in the radial direction from the openings 19a of the second group, which is connected via a further screw or vibrating trough 27, in order to have a to bring about a uniform distribution of the raw material mixture or the shards on the surface of the glass melt 12.
  • Each storage container 24 receives additional raw materials/shards from the stationary storage container, not shown, when it is guided past the stationary container by 360° during the continuous rotational movement of the rotating ceiling and is arranged underneath it for a predetermined time.
  • the dosage in particular of the screw or vibrating trough 27 can be designed in such a way that the further co-rotating storage containers 28 located further inside receive a smaller amount of starting materials than the co-rotating storage containers 28 located further out.
  • the side wall 13 and the transition wall 16 are composed of palisade elements arranged one above and next to one another. This can be seen in the cutaway view in FIG. 1 at the respective end of the side wall 13 and the transition wall 16.
  • a small shoulder 13e is arranged, which is formed by horizontally extending palisade elements.
  • these palisade elements are arranged next to or one above the other as shown, attached to or next to the raised floor section 14 or to or next to the homogenizing floor section 15 and, as described above, held by a steel frame 36 and steel beams 38.
  • a power supply device 20 sketched in FIG. 1 which has three transformers which supply the total of thirty-six electrodes 17, 18.
  • the thirty-six electrodes are divided into three groups of 6 electrode pairs each and each group is assigned to a transformer using the open three-phase system. Two transformers are connected on the primary side in a delta connection (offset by 60 °, first delta connection marked in Fig.
  • the delta connections each having opposite inner electrodes (pairs) 18 and outer electrodes (pairs ) 17 include. Furthermore, a transformer is designed in a star connection (see connection marked by dash-dot lines), whereby the star connection only includes external electrodes (pairs). Since the geometric/mechanical arrangement of the electrodes in the glass melting tank follows the position of the pointers in the electrical pointer diagram, there is a uniform current load on all electrodes. Since the distances between associated electrodes/heating partners are not too long, manageable values for the operating voltage/secondary voltage result.
  • Identical elements have the same reference number in the tens and ones position of the respective number of the reference number, whereby the reference numbers of different embodiments differ by whole 100s.
  • the outer electrodes have the reference number 18 in the first embodiment and 118 in the second and 218 in the third embodiment, etc.
  • the second exemplary embodiment of a glass melting tank 110 shown in FIGS. 7 and 8 has an average diameter D above the raised floor section 114 of 11 m.
  • the average diameter d in the area of the homogenization space is approximately 5.4 m.
  • the channel 111c which connects the homogenization space with the outlet opening 113a in the area of the side wall 113, has a channel-shaped depression 111d, which causes the outlet opening 113a with its lower end below the homogenization base section 115.
  • the depression 111d extends into the homogenization bottom section 115. This promotes the removal of well-homogenized glass melt.
  • the width of the depression 111d in the horizontal direction is, for example, 400 mm.
  • the third embodiment of a glass melting tank 210 corresponds to the second embodiment, with the raised floor section 214 being wider in the horizontal direction than in the second embodiment.
  • the diameter d in the area of the homogenization chamber is approximately 3.6 m, so that the width of 2.8 m (width of the raised floor section 114 of the second embodiment) to 3.7 m. This brings the inner electrodes 18 closer together and the flow in the melting and refining chamber is evened out, which has a positive effect on the glass quality.
  • the fourth exemplary embodiment of a glass melting tank 310 shown in FIGS. 11 to 14 differs from the first exemplary embodiment in that the homogenization space has the shape of a 6-sided prism due to the corresponding design of the transition wall 316 and the raised bottom section 314.
  • the width B of the melting and refining space above the raised floor section 314 is, for example, 14 m and the average diameter d of the homogenization space is, for example, 7 m.
  • the height difference h 1.8 m and is therefore larger than in the first exemplary embodiment. This also results in better homogenization of the glass melt 12.
  • the outlet opening 313a is arranged at the lower end of the transition wall 316.
  • the raised floor section 314 extends completely around the homogenization space, as shown in FIG. 13, i.e. without being interrupted by a channel.
  • the rotating storage container for the raw material mixture and/or the shards is arranged centrally to the glass melting tank 310 above the screw or vibrating troughs 327.
  • the stationary storage container is also located centrally above the glass melting tank 310.
  • the dynamics in the melting and refining chamber can be evened out by the more uniform arrangement of the electrodes, which is caused by the widening of the raised floor section 414.
  • the sixth embodiment of a glass melting tank 510 is shown in Figs. 17 to 21. This differs from the third embodiment in the shape of the channel 511c, which runs from the homogenization chamber to the outlet opening 513a and serves to discharge the homogenized glass melt.
  • the glass melting tank 510 also has a feeding device for feeding the raw material mixture and/or the glass cullet analogously to the fourth embodiment.
  • the seventh embodiment of a glass melting tank shown in FIGS. 22 to 26 is very similar to the first embodiment. In contrast to this, it has two outlet openings 613a, which are arranged opposite each other at the bottom of the side wall 613 along the circumferential direction. This results in a uniform withdrawal of the homogenized glass melt. Accordingly, two channels 611c are provided opposite each other, which lead the glass melt to the respective outlet opening 613a.
  • a collar 716a can be provided on the transition wall 716, which, for example, has a height of approximately 100 mm measured in the vertical direction from the raised bottom section 714 and a width in the horizontal direction of 150 mm.
  • the collar is integrated into the raised floor section in the area on the inner edge and forms This section of the floor is merely an increase.
  • the collar 716a prevents bubbles from flowing directly toward the outlet opening 713a.
  • the structure of the glass melting tank with regard to the steel frame will be explained in more detail below using a ninth exemplary embodiment of a glass melting tank 810 shown in FIG. 33.
  • a glass melting tank 810 shown in FIG. 33 In the exemplary embodiment shown in FIG. 33, three through openings 819a are arranged in the rotating ceiling 819, which serve to feed raw material mixtures and/or shards. Otherwise, the glass melting tank 810 has the structure of the first exemplary embodiment.
  • the side wall 813 has an outer steel frame 36, which holds and fixes the palisade elements of the side wall 813.
  • a circular guide rail 36a is provided, on which rollers 819c are guided in such a way that the rotating ceiling can rotate through 360 ° in a first direction of rotation and in the opposite direction of rotation.
  • the rollers 819c are connected to the steel frame 38 of the rotating ceiling 819.
  • the steel frame 38 of the rotating ceiling 819 has an annular sealing apron 819d with a sealing edge, each sealing apron 819d being guided in a circular sealing groove 36b with sand in a sealing manner.
  • the sealing groove 36b is arranged on the upper end face of the side wall 813.
  • D is the diameter above the raised bottom section
  • the area A1 is the size of the melt surface
  • H is the height of the side wall above the raised bottom section (see Figs. 2 and 3)
  • DEG1 is the diameter of a horizontal circle/line on which the first Group of electrodes is arranged (if these are top or bottom electrodes), d the diameter of the homogenization space
  • A2 the cross-sectional area of the homogenization space
  • h the height of the homogenization space or the height difference between the raised bottom section and the Homogenization bottom section
  • DEG2 the diameter of a horizontal circle/line on which the second group of electrodes is arranged
  • DEG2/DEG1 the ratio of the diameters DEG2 and DEG1, the ratio of the width of the raised bottom section to the radius of the melting and refining space
  • V that Volume of the glass melt arranged in the respective glass melting tank
  • B the width of the raised bottom section
  • T the throughput

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Abstract

L'invention concerne une cuve pour le chauffage entièrement électrique d'une masse fondue de verre située à l'intérieur d'une cuve, ladite cuve comprenant un fond en gradins, une pluralité d'électrodes, et une paroi latérale, et permettant d'obtenir un débit de 80 à 450 tonnes/jour et une bonne qualité de verre. Le côté chambre chaude de la paroi latérale forme, au-dessus de la partie inférieure surélevée, un polygone ayant au moins cinq côtés, un cercle ou une ellipse en coupe transversale horizontale. Le fond a une partie inférieure surélevée s'étendant environ sur au moins 70 % de la périphérie de l'intérieur de cuve et une partie inférieure d'homogénéisation centrale qui est entourée par et en dessous de la partie inférieure surélevée, la partie inférieure surélevée s'étendant latéralement à partir du côté chambre chaude de la paroi latérale dans la direction de l'intérieur de cuve et ayant une largeur qui est supérieure ou égale à 0,25 x D (D étant le diamètre moyen) ; dans la transition entre la partie inférieure surélevée et la partie inférieure d'homogénéisation, une paroi de transition est formée s'étendant perpendiculairement par rapport à la surface de la masse fondue de verre ; et un premier groupe de la pluralité d'électrodes se projette dans la masse fondue de verre dans une région adjacente à la paroi latérale et un second groupe de la pluralité d'électrodes est situé dans la partie inférieure surélevée dans une région adjacente à la paroi de transition.
PCT/EP2023/075974 2022-09-20 2023-09-20 Cuve de fusion de verre WO2024061987A1 (fr)

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DE102022124155.6A DE102022124155A1 (de) 2022-09-20 2022-09-20 Glasschmelzwanne
DE102022124155.6 2022-09-20

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Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3440321A (en) * 1966-06-18 1969-04-22 Elemelt Ltd Furnaces for heating glass electrically
US3520979A (en) 1968-02-26 1970-07-21 Penelectro Ltd Electrode circuit for hex electric furnace
US3683093A (en) 1969-12-20 1972-08-08 Element Ltd Furnaces for heating glass
JPS52119617A (en) * 1971-01-05 1977-10-07 Sorg Nikolaus Gmbh & Co Kg Electric melting furnace of glass
US3885945A (en) 1974-03-20 1975-05-27 Owens Corning Fiberglass Corp Method of and apparatus for electrically heating molten glass
JPS6024055B2 (ja) 1977-07-21 1985-06-11 旭硝子株式会社 ガラス電気熔融炉
DE3405273C2 (fr) 1984-02-15 1988-11-24 Sorg Gmbh & Co Kg, 8770 Lohr, De
JPS61222928A (ja) 1985-03-28 1986-10-03 Hoya Corp ガラス熔融用電気炉
CN201301270Y (zh) * 2008-11-27 2009-09-02 中国京冶工程技术有限公司 蓄热式玻璃坩埚圆窑
CN203728700U (zh) * 2014-03-13 2014-07-23 珠海市威望节能科技有限公司 一种废热再利用的环形玻璃窑炉
US20220194838A1 (en) * 2019-07-04 2022-06-23 International Partners In Glass Research Glass melting furnace

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