CA1088313A - Refining apparatus - Google Patents
Refining apparatusInfo
- Publication number
- CA1088313A CA1088313A CA271,541A CA271541A CA1088313A CA 1088313 A CA1088313 A CA 1088313A CA 271541 A CA271541 A CA 271541A CA 1088313 A CA1088313 A CA 1088313A
- Authority
- CA
- Canada
- Prior art keywords
- channel
- foaming zone
- foaming
- width
- electrodes
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
Links
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
- C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
- C03B5/18—Stirring devices; Homogenisation
- C03B5/183—Stirring devices; Homogenisation using thermal means, e.g. for creating convection currents
- C03B5/185—Electric means
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- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Glass Melting And Manufacturing (AREA)
- Glass Compositions (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
- Furnace Details (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The improvement in an apparatus for refining glass being fed along a channel wherein the molten glass is foamed throughout its thickness, the improvement involving an increase in the width of the channel at the location of foaming. Also, the channel is provided with submerged electrodes disposed on opposite sides of the channel adjacent the bottom for heating the molten mass to produce the foaming.
The improvement in an apparatus for refining glass being fed along a channel wherein the molten glass is foamed throughout its thickness, the improvement involving an increase in the width of the channel at the location of foaming. Also, the channel is provided with submerged electrodes disposed on opposite sides of the channel adjacent the bottom for heating the molten mass to produce the foaming.
Description
BACKGROUND OF T~E INVENTION
In Canadian Patent Application No. 233,203 filed August 11, 1975 and entitled "Method and Apparatus for the ~anu-facture of Glass", a rapid process of melting and refining glass is described in which a vitrifiable material is melted and brought to an elevated temperature while maintaining the viscosity of the molten mass at less than 1000 poises. As soon as the melting has been achieved, an intense foaming of the molten mass is effected throughout its entire thickness while keeping the viscosity at a value less than 1000 poises. The rate of expansion of the mass is at least 1.5 (preferably between 2 and 3). After the foaming subsides, a perfectly refined glass is collected.
According to the process disclosed in said copending application, the foaming operation is performed in a channel in which the molten material progresses, without back currents, from a first location where the raw vitreous material is received from a premelting apparatus to a second location where the refined glass is recovered.
To ensure the intense and complete foaming required, a number of steps may be taken. For example, foaming agents can be incorporated into the raw materials. The foaming agents give rise, in the temperature range, corresponding to the desired viscosities, to the formation of gas bubbles inside the glass.
The gases produced by the foaming agents are soluble in glass, and preferably their solubility inthe molten glass increases as its temperature decreases. It is also recommended that a refining agent be present, at least in the final phàse. After the elimi-nation of most of the gases, the refining agents aid in the readsorption of the bubbles which remain on cooling. The foaming -agents are selected such that they do not induce foaming of the ~'" ~
1088~11J
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1 ¦vitreous material until that material has reached a desired
In Canadian Patent Application No. 233,203 filed August 11, 1975 and entitled "Method and Apparatus for the ~anu-facture of Glass", a rapid process of melting and refining glass is described in which a vitrifiable material is melted and brought to an elevated temperature while maintaining the viscosity of the molten mass at less than 1000 poises. As soon as the melting has been achieved, an intense foaming of the molten mass is effected throughout its entire thickness while keeping the viscosity at a value less than 1000 poises. The rate of expansion of the mass is at least 1.5 (preferably between 2 and 3). After the foaming subsides, a perfectly refined glass is collected.
According to the process disclosed in said copending application, the foaming operation is performed in a channel in which the molten material progresses, without back currents, from a first location where the raw vitreous material is received from a premelting apparatus to a second location where the refined glass is recovered.
To ensure the intense and complete foaming required, a number of steps may be taken. For example, foaming agents can be incorporated into the raw materials. The foaming agents give rise, in the temperature range, corresponding to the desired viscosities, to the formation of gas bubbles inside the glass.
The gases produced by the foaming agents are soluble in glass, and preferably their solubility inthe molten glass increases as its temperature decreases. It is also recommended that a refining agent be present, at least in the final phàse. After the elimi-nation of most of the gases, the refining agents aid in the readsorption of the bubbles which remain on cooling. The foaming -agents are selected such that they do not induce foaming of the ~'" ~
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1 ¦vitreous material until that material has reached a desired
2 ¦temperature, which temperature is maintained in the refining
3 ¦channel. The following foaming agents are useful in the process ¦disclosed in said copending application: arsenic compounds, such 5 ¦as arsenic trioxide; antimony compounds such as antimony trioxide;
6 ¦sulfur compounds, such as sodium sulfate; and halogen salts such 7 ¦as potassium chloride. Other agents useful in the process will ¦ be apparent to those skilled in the art.
91 Another method disclosed in said copending application 10¦ for ensuring the thorough foaming of the molten mass involves 11¦ subjecting the batch to rapid uniform heating during the foaming 12¦ operation of about 20C per minute or more.
13¦ In a discontinuous melting installation, the heating 14 means are employed at a time when the vitreous batch contains a large number of solid or gaseous nuclei and a sufficient amount 16 of foaming agents to ensure an expansion of at least 1.5, and 17 preferably above 2 times the normal volume of the mass in the 18 unfoamed molten state.
19 In a continuous melting installation similar heating means can be employed. The predefined time sequence corresponds 21 to the rate of treatment of the vitreous mass.
22 To aid the foaming process, it is also recommended 23 that the raw materials contain a large number of nuclei, such as 24 unmelted particules or small gas bubbles, capable of inducing the foaming. These nuclei essentially act as nucleation sites.
26 The nuclei should be distributed throughout the molten mass at a 27 concentration of at least 10 nuclei per cc. Generally , it is desirable that the raw materials be agglomerated. The agglomer~
29 makes it possible to preheat the materials before actual melting.
The preheating is accomplished by a brief and intense heat '~ ~088313 ~
transfer (less than 10 minutes) while simultaneously keeping the temperature of the materials below the foaming temperature. This permits the maintenance of a high number of nuclei consisting of unmelted particles and gas bubbles in the vitreous mass introduced into the total foaming stage.
To assure the presence of sufficient nuclei, outside nuclei, for example, cullet or colored cullet can be added to the raw materials. In relation to the usual glass refining processes, the process disclosed in said copending application, requiring the presence of gas producing agents and foaming nuclei, can employ unrefined vitreous materials. It has been discovered that 1 to 2 mm. grains originating from the limestone and dolomite in the material introduced in the refining tank, are totally digested at the end of the total foaming phase. The process is therefore -not dependent on the use of a vitreous batch of high quality.
The channel in which the molten mass flows can be of very simple geometry. Preferably, it has a slight width in relation --to its length, in a ratio of 1:5 at least. This construction limits-undesirable back currents. Also, for this same purpose, it is possible to use baffles, barriers, bottlenecks or even cascades along the path traveled by the vitreous molten mass during treatment in the channel of the refining apparatus.
SU.~ARY OF THE PRESENT IWVENTION
According to the present invention, the channel of the refining apparatus is constructed to increase the homogeneity of the foaming of the molten mass throughout its entire thickness.
The construction of the channel also enhances the uniform flow of the molten mass. More particularly, the apparatus includes -an elongated continuous flow refining channel in which a molten vitreous mass is introduced at one end thereof and flowed ~3313 horizontally therethrough to an exit at its other end. A
localized foaming zone extends along a predetermined length of said channel and is spaced from the one end thereof. The foaming zone has a width appreciably wider than the channel upstream thereof. Heating means are submerged along the length of the channel for subjecting the flowing molten mass in the foaming zone to an expansion of at least 50% of its initial molten volume by foaming the flowing molten mass in the foaming zone throughout its entire volume as the mass moves along the channel from its one end to the other end.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a plan view of the channel constructed in accordance with the present invention; and Fig. 2 is a cross-sectional view of the channel, in the widened or foaming zone as taken along lines II-II of Fig. 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In Fig. 1, the direction of the arrow indicates the direction of flow of the molten mass between electrodes El. The channel walls diverge at 1 to define the entrance of the foaming or widened zone 2. The electrodes E2 in the foaming zone are placed at a distance apart greater than the width of the channel upstream. Thus, the totality of the molten glass mass that comes from there enters between electrodes E2. The length of the widened foaming zone corresponds to the period of the intense foaming phase disclosed in the above-mentioned copending application. The dissipation of energy by Joule effect is produced within the vitreous mass itself to control the temperature of the mass all along the channel.
The wall of the foaming zone is moderately heat insulated to maintain its temperature at a rather low level (on , , 10~3313 the order of 1350C), whereas the glass in foam state between electrodes E2 is around 1550C. From this important heat gradient, there results, around each electrode E2, a notable convection current, helicoidal in shape in the direction indi-cated by the arrows represented in Fig. 2. This causes an intense mixing of the molten glass mass particularly favorable to its refining.
The glass has free passage around the electrodes along the hearth and side walls. Passage of the current from one electrode to the other produces active thermal convection which favors the crosswise homogenization of the molten mass and eliminates any major longitudinal currents. The result is a uniform flow of glass called a "piston" flow. In Fig. 2, the level of molten mass before foaming is shown by the broken lines while that of the foam is shown by the solid lines.
By way of example, an embodiment of the invention for refining glass at a production capacity on the order of 120 to 250 kg/hour, for the usual silica-soda-lime glass, is given below.
The walls and hearth of the channel are made up of blocks of electro-melted refractory 3 with a base of alumina and zirconia about 10 cm. thick, heat insulated by a lining 4 of refractory bricks. To obtain a moderate heat insulation in the widened foaming zone 2, a thinner lining thickness 4 is used.
The hearth 5 of the channel is level on its entire surface.
The depth of the channel is 25 cm., uniformly over its entire length, which totals 2.5 m. The narrow upstream zone, in which receipt of the premelted mass occurs, is 30 cm. wide and 40 cm. long. The two electrodes El in this zone are made of molybdenum rods 40 mm. in diameter and 40 cm. long. They are placed symmetrically and 150 mm. apart.
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108~i313 1 ¦ After this upstream zone, the widened foaming zone 2 lextends for a total length of 80 cm. It inciudes the entrance 1 3 ¦where the walls diverge over a length of 15 cm. This increases
6 ¦sulfur compounds, such as sodium sulfate; and halogen salts such 7 ¦as potassium chloride. Other agents useful in the process will ¦ be apparent to those skilled in the art.
91 Another method disclosed in said copending application 10¦ for ensuring the thorough foaming of the molten mass involves 11¦ subjecting the batch to rapid uniform heating during the foaming 12¦ operation of about 20C per minute or more.
13¦ In a discontinuous melting installation, the heating 14 means are employed at a time when the vitreous batch contains a large number of solid or gaseous nuclei and a sufficient amount 16 of foaming agents to ensure an expansion of at least 1.5, and 17 preferably above 2 times the normal volume of the mass in the 18 unfoamed molten state.
19 In a continuous melting installation similar heating means can be employed. The predefined time sequence corresponds 21 to the rate of treatment of the vitreous mass.
22 To aid the foaming process, it is also recommended 23 that the raw materials contain a large number of nuclei, such as 24 unmelted particules or small gas bubbles, capable of inducing the foaming. These nuclei essentially act as nucleation sites.
26 The nuclei should be distributed throughout the molten mass at a 27 concentration of at least 10 nuclei per cc. Generally , it is desirable that the raw materials be agglomerated. The agglomer~
29 makes it possible to preheat the materials before actual melting.
The preheating is accomplished by a brief and intense heat '~ ~088313 ~
transfer (less than 10 minutes) while simultaneously keeping the temperature of the materials below the foaming temperature. This permits the maintenance of a high number of nuclei consisting of unmelted particles and gas bubbles in the vitreous mass introduced into the total foaming stage.
To assure the presence of sufficient nuclei, outside nuclei, for example, cullet or colored cullet can be added to the raw materials. In relation to the usual glass refining processes, the process disclosed in said copending application, requiring the presence of gas producing agents and foaming nuclei, can employ unrefined vitreous materials. It has been discovered that 1 to 2 mm. grains originating from the limestone and dolomite in the material introduced in the refining tank, are totally digested at the end of the total foaming phase. The process is therefore -not dependent on the use of a vitreous batch of high quality.
The channel in which the molten mass flows can be of very simple geometry. Preferably, it has a slight width in relation --to its length, in a ratio of 1:5 at least. This construction limits-undesirable back currents. Also, for this same purpose, it is possible to use baffles, barriers, bottlenecks or even cascades along the path traveled by the vitreous molten mass during treatment in the channel of the refining apparatus.
SU.~ARY OF THE PRESENT IWVENTION
According to the present invention, the channel of the refining apparatus is constructed to increase the homogeneity of the foaming of the molten mass throughout its entire thickness.
The construction of the channel also enhances the uniform flow of the molten mass. More particularly, the apparatus includes -an elongated continuous flow refining channel in which a molten vitreous mass is introduced at one end thereof and flowed ~3313 horizontally therethrough to an exit at its other end. A
localized foaming zone extends along a predetermined length of said channel and is spaced from the one end thereof. The foaming zone has a width appreciably wider than the channel upstream thereof. Heating means are submerged along the length of the channel for subjecting the flowing molten mass in the foaming zone to an expansion of at least 50% of its initial molten volume by foaming the flowing molten mass in the foaming zone throughout its entire volume as the mass moves along the channel from its one end to the other end.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a plan view of the channel constructed in accordance with the present invention; and Fig. 2 is a cross-sectional view of the channel, in the widened or foaming zone as taken along lines II-II of Fig. 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In Fig. 1, the direction of the arrow indicates the direction of flow of the molten mass between electrodes El. The channel walls diverge at 1 to define the entrance of the foaming or widened zone 2. The electrodes E2 in the foaming zone are placed at a distance apart greater than the width of the channel upstream. Thus, the totality of the molten glass mass that comes from there enters between electrodes E2. The length of the widened foaming zone corresponds to the period of the intense foaming phase disclosed in the above-mentioned copending application. The dissipation of energy by Joule effect is produced within the vitreous mass itself to control the temperature of the mass all along the channel.
The wall of the foaming zone is moderately heat insulated to maintain its temperature at a rather low level (on , , 10~3313 the order of 1350C), whereas the glass in foam state between electrodes E2 is around 1550C. From this important heat gradient, there results, around each electrode E2, a notable convection current, helicoidal in shape in the direction indi-cated by the arrows represented in Fig. 2. This causes an intense mixing of the molten glass mass particularly favorable to its refining.
The glass has free passage around the electrodes along the hearth and side walls. Passage of the current from one electrode to the other produces active thermal convection which favors the crosswise homogenization of the molten mass and eliminates any major longitudinal currents. The result is a uniform flow of glass called a "piston" flow. In Fig. 2, the level of molten mass before foaming is shown by the broken lines while that of the foam is shown by the solid lines.
By way of example, an embodiment of the invention for refining glass at a production capacity on the order of 120 to 250 kg/hour, for the usual silica-soda-lime glass, is given below.
The walls and hearth of the channel are made up of blocks of electro-melted refractory 3 with a base of alumina and zirconia about 10 cm. thick, heat insulated by a lining 4 of refractory bricks. To obtain a moderate heat insulation in the widened foaming zone 2, a thinner lining thickness 4 is used.
The hearth 5 of the channel is level on its entire surface.
The depth of the channel is 25 cm., uniformly over its entire length, which totals 2.5 m. The narrow upstream zone, in which receipt of the premelted mass occurs, is 30 cm. wide and 40 cm. long. The two electrodes El in this zone are made of molybdenum rods 40 mm. in diameter and 40 cm. long. They are placed symmetrically and 150 mm. apart.
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108~i313 1 ¦ After this upstream zone, the widened foaming zone 2 lextends for a total length of 80 cm. It inciudes the entrance 1 3 ¦where the walls diverge over a length of 15 cm. This increases
4 ¦the width of the channel from 30 to 60 cm., this latter value
5 ¦being maintained over a length of 50 cm. The channel then com-
6 ¦prises a narrowing portion 6 where, over a length of 15 cm., the ¦walls converge to reduce the width of the channel from 60 to 30 8 ¦cm. This reduced width is then maintained over the downstream 9¦ zone, for a length of 1.3 m., to the drawing off orifice 7, whose 10¦ output is controlled by a needle system, not shown.
11¦ Electrodes E2 in the widened foaming zone are made of 12¦ cylindrical molybdenum rods 40 mm. in diameter and are 70 cm.
13¦ long. The pairs of electordes E3, E4 and E5 in the downstream 14¦ zone of the channel are of the same diameter (40 mm.) and are 30 15 cm. long. For the areas where the molybdenum is in contact with 16 the molten mass, even in the upstream zone and in the widened 17 foaming zone where the mass is charged with bubbles of various 18 gases, it has been found tha~ with the usual compositions of 19 silica-soda-lime glass, no particular precautions need be taken 20 for the protecting of this metal from oxidation.
21 The current lead-ins 8 to the electrodes are also moly-22 bdenum rods, but their diameters are only 25 mm. Assembly of the 23 lead-in and electrode is accomplished by screwing of one into the 24 other. In the areas where there is a danger of oxidation of the 25 molybdenum of the lead-ins, they are protected,-as is known, by 26 a reducing gas such as town gas. The connecting clamps to the 27 electric supply are cooled by circulation of liquid. The lead-ins 28 can slide in passages 8a which are made through the walls of the 29 channel. The height of/these passages is 5 cm. above the level of l~ 30 the hearth except for electrodes E2 whose height is 2 cm. greater.
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¦ Between the pair of electrodes E4 and E5, a barrier of .-2¦ refractory material or platinum is placed to provide a passage of 31 adjustable height between its lower part and the hearth 5. The 41 barrier blocks possible surface currents; and is slidably mounted i 51 in guides 10 in the lateral walls of the channel to control the 61 flow of molten mass.
71 Heating of the molten mass contained in the channel is .
81 assured by means of the immersed electrodes, previously described, 91 with independent electric power supply for each pair of electrodes 10¦ An example of the rated electrical characteristics of the power .
11¦ supply is as follows:
12¦ Power Current 13¦ Powers Used C ~ ~ Amperage 14¦ electrodes El 40 80 500 15¦ electrodes E2 40 80 500 16¦ -electrodes E3 7.5 120 62.5 17¦ .electrodes E4 7.5 120 62.5 18¦ electrodes E5 15 120 125 19¦ The above-described construction and power supply permit~ ; :~
20¦ refining of about 150 kg/hour of silica-soda-lime glass under ¦
. 21¦ operating conditions shown in the following table, the temperatures 22¦ being those indicated by pyrométers going into the molten mass at 231 points indicated Tl to T5 in Fig. 1:
24 .
251Powers Used Values Temperatures Measured Values 26¦electrodes El 15 Point of Measurement Tl 1300 271electrodes E2 22 Point of Measurement T2 1480 28¦electrodes E3 1 Point of Measurement T3 1540 29¦electrodes E4 1 Point of Measurement T4 1400 30 ¦electrodes E5 0 Point of Measurement Ts 1250 1 The operating conditions correspond to a supply of 2 premelted paste delivered at about 1350C by a melting apparatus 3 of the type disclosed in the above-mentioned copending application in which the following vitrifiable mixture (in kg. per 100 kg. of 5 glass) is introduced in the form of agglomerates.
6 sand 67.0
11¦ Electrodes E2 in the widened foaming zone are made of 12¦ cylindrical molybdenum rods 40 mm. in diameter and are 70 cm.
13¦ long. The pairs of electordes E3, E4 and E5 in the downstream 14¦ zone of the channel are of the same diameter (40 mm.) and are 30 15 cm. long. For the areas where the molybdenum is in contact with 16 the molten mass, even in the upstream zone and in the widened 17 foaming zone where the mass is charged with bubbles of various 18 gases, it has been found tha~ with the usual compositions of 19 silica-soda-lime glass, no particular precautions need be taken 20 for the protecting of this metal from oxidation.
21 The current lead-ins 8 to the electrodes are also moly-22 bdenum rods, but their diameters are only 25 mm. Assembly of the 23 lead-in and electrode is accomplished by screwing of one into the 24 other. In the areas where there is a danger of oxidation of the 25 molybdenum of the lead-ins, they are protected,-as is known, by 26 a reducing gas such as town gas. The connecting clamps to the 27 electric supply are cooled by circulation of liquid. The lead-ins 28 can slide in passages 8a which are made through the walls of the 29 channel. The height of/these passages is 5 cm. above the level of l~ 30 the hearth except for electrodes E2 whose height is 2 cm. greater.
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¦ Between the pair of electrodes E4 and E5, a barrier of .-2¦ refractory material or platinum is placed to provide a passage of 31 adjustable height between its lower part and the hearth 5. The 41 barrier blocks possible surface currents; and is slidably mounted i 51 in guides 10 in the lateral walls of the channel to control the 61 flow of molten mass.
71 Heating of the molten mass contained in the channel is .
81 assured by means of the immersed electrodes, previously described, 91 with independent electric power supply for each pair of electrodes 10¦ An example of the rated electrical characteristics of the power .
11¦ supply is as follows:
12¦ Power Current 13¦ Powers Used C ~ ~ Amperage 14¦ electrodes El 40 80 500 15¦ electrodes E2 40 80 500 16¦ -electrodes E3 7.5 120 62.5 17¦ .electrodes E4 7.5 120 62.5 18¦ electrodes E5 15 120 125 19¦ The above-described construction and power supply permit~ ; :~
20¦ refining of about 150 kg/hour of silica-soda-lime glass under ¦
. 21¦ operating conditions shown in the following table, the temperatures 22¦ being those indicated by pyrométers going into the molten mass at 231 points indicated Tl to T5 in Fig. 1:
24 .
251Powers Used Values Temperatures Measured Values 26¦electrodes El 15 Point of Measurement Tl 1300 271electrodes E2 22 Point of Measurement T2 1480 28¦electrodes E3 1 Point of Measurement T3 1540 29¦electrodes E4 1 Point of Measurement T4 1400 30 ¦electrodes E5 0 Point of Measurement Ts 1250 1 The operating conditions correspond to a supply of 2 premelted paste delivered at about 1350C by a melting apparatus 3 of the type disclosed in the above-mentioned copending application in which the following vitrifiable mixture (in kg. per 100 kg. of 5 glass) is introduced in the form of agglomerates.
6 sand 67.0
7 limestone 9.47
8 dolomite 16.2
9 feldspar 6.13 sodium carbonate 7.58 11 50% caustic soda 22.5 12 sodium sulfate 1.0 13 The minimum level of the unexpanded molten glass mass 14 should be on the order of 10 cm. to cover, and therefore protect 15 from oxidation, the totality of the various pairs of electrodes 16 disposed along the channel, even if the rate of expansion is 17 small. In practice, in the installation described, the rate of expansion of about2 permits optimal functioning, while leaving a 19 safety space of 5 cm. above the molten mass.
Devices with greater production capacity can be made in 21 a way similar to the above-described embodiment. Appropriate 22 electrical heating means must be provided in relation to the 23 contemplated output, i.e., heating means with a capacity to assure 24 an elevation of temperature of the vitreous mass of at least 20C/
25 minute-at the level of the widened foaming zone. Also, if the , 26 thickness of the molten glass mass is increased, the electrodes 27 are still kept close to the hearth, as indicated above, so that 28 the heat will directly affect the deepest layers of the mass to 29 be treated. Thus, unwanted currents of longitudinal convection 30 are reduced, to the benefit of the quality of the refining. For 1 similar reasons, particular care is given to heat insulation of 2 the hearth while the arch and walls are, optionally, as stated 3 above, slightly less heat insulated to favor transverse convection -.
5~movements 19 . .
21 .
22 .
28 . .
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, . . . .: . :, . , : .
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Devices with greater production capacity can be made in 21 a way similar to the above-described embodiment. Appropriate 22 electrical heating means must be provided in relation to the 23 contemplated output, i.e., heating means with a capacity to assure 24 an elevation of temperature of the vitreous mass of at least 20C/
25 minute-at the level of the widened foaming zone. Also, if the , 26 thickness of the molten glass mass is increased, the electrodes 27 are still kept close to the hearth, as indicated above, so that 28 the heat will directly affect the deepest layers of the mass to 29 be treated. Thus, unwanted currents of longitudinal convection 30 are reduced, to the benefit of the quality of the refining. For 1 similar reasons, particular care is given to heat insulation of 2 the hearth while the arch and walls are, optionally, as stated 3 above, slightly less heat insulated to favor transverse convection -.
5~movements 19 . .
21 .
22 .
28 . .
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Claims (12)
1. The improvement in an apparatus for refining glass comprising:
(a) an elongated continuous flow refining channel in which a molten vitreous mass is intro-duced at one end thereof and flowed horizontally therethrough to an exit at its other end;
(b) a localized foaming zone extending along a predetermined length of said channel and spaced from the one end thereof, said foaming zone having a width appreciably wider than the channel upstream of said foaming zone; and (c) heating means submerged along the length of said channel for subjecting the flowing molten mass in said foaming zone to an expansion of at least 50% of its initial molten volume by foaming the flowing molten mass in said foaming zone throughout its entire volume as the mass moves along the channel from its one end to the other end.
(a) an elongated continuous flow refining channel in which a molten vitreous mass is intro-duced at one end thereof and flowed horizontally therethrough to an exit at its other end;
(b) a localized foaming zone extending along a predetermined length of said channel and spaced from the one end thereof, said foaming zone having a width appreciably wider than the channel upstream of said foaming zone; and (c) heating means submerged along the length of said channel for subjecting the flowing molten mass in said foaming zone to an expansion of at least 50% of its initial molten volume by foaming the flowing molten mass in said foaming zone throughout its entire volume as the mass moves along the channel from its one end to the other end.
2. The apparatus according to claim 1 wherein:
(a) the width of the channel in said foaming zone is about twice the width of the channel upstream thereof.
(a) the width of the channel in said foaming zone is about twice the width of the channel upstream thereof.
3. The apparatus according to claim 2 wherein:
(a) the width of the channel downstream of the foaming zone is about equal to the width upstream of the foaming zone.
(a) the width of the channel downstream of the foaming zone is about equal to the width upstream of the foaming zone.
4. The apparatus according to claim 3 wherein:
(a) the length of the channel is about eight times the width of the channel upstream and down-stream of the foaming zone; and (b) the length of the foaming zone is about twice that of the channel upstream thereof.
(a) the length of the channel is about eight times the width of the channel upstream and down-stream of the foaming zone; and (b) the length of the foaming zone is about twice that of the channel upstream thereof.
5. The apparatus according to claim 2 wherein the improvement further includes:
(a) a plurality of pairs of electrodes positioned in opposed relation along opposite sides of the channel in submerged relation to the molten mass.
(a) a plurality of pairs of electrodes positioned in opposed relation along opposite sides of the channel in submerged relation to the molten mass.
6. The apparatus according to claim 5 wherein:
(a) the electrodes have a heating capacity sufficient to increase the temperature of the molten mass by at least 20°C per minute.
(a) the electrodes have a heating capacity sufficient to increase the temperature of the molten mass by at least 20°C per minute.
7. The apparatus according to claim 5 wherein:
(a) the opposed electrodes of each pair extend parallel to each other and to the sides of the channel in spaced relation thereto; and (b) the spacing between the electrodes in the foaming zone is at least equal to the width of the channel upstream of the foaming zone.
(a) the opposed electrodes of each pair extend parallel to each other and to the sides of the channel in spaced relation thereto; and (b) the spacing between the electrodes in the foaming zone is at least equal to the width of the channel upstream of the foaming zone.
8. The apparatus according to claim 7 wherein:
(a) the electrodes extend horizontally near the bottom of the channel; and (b) a single pair of electrodes is disposed in said foaming zone and extends substantially the length of the foaming zone.
(a) the electrodes extend horizontally near the bottom of the channel; and (b) a single pair of electrodes is disposed in said foaming zone and extends substantially the length of the foaming zone.
9. The apparatus according to claim 8 wherein:
(a) the spacing of the electrodes from the sides of the channel is greater in the foaming zone than along the remainder of the channel.
(a) the spacing of the electrodes from the sides of the channel is greater in the foaming zone than along the remainder of the channel.
10. The apparatus according to claim 8 wherein:
(a) the spacing of the electrodes in the foaming zone is about equal to the width of the channel upstream of the foaming zone.
(a) the spacing of the electrodes in the foaming zone is about equal to the width of the channel upstream of the foaming zone.
11. The apparatus according to claim 10 wherein:
(a) the width of the channel downstream of the foaming zone is equal to the width upstream of the foaming zone;
(b) the length of the channel is about eight times the width of the channel upstream and downstream of the foaming zone; and (c) the length of the foaming zone is about twice that of the channel upstream thereof.
(a) the width of the channel downstream of the foaming zone is equal to the width upstream of the foaming zone;
(b) the length of the channel is about eight times the width of the channel upstream and downstream of the foaming zone; and (c) the length of the foaming zone is about twice that of the channel upstream thereof.
12. The apparatus according to claim 11 wherein:
(a) the sides of the channel are more moderately insulated in the foaming zone than upstream and downstream thereof.
(a) the sides of the channel are more moderately insulated in the foaming zone than upstream and downstream thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7603813A FR2340911A1 (en) | 1976-02-12 | 1976-02-12 | GLASS REFINING DEVICE |
| FR7603813 | 1976-02-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1088313A true CA1088313A (en) | 1980-10-28 |
Family
ID=9169015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA271,541A Expired CA1088313A (en) | 1976-02-12 | 1977-02-11 | Refining apparatus |
Country Status (14)
| Country | Link |
|---|---|
| JP (1) | JPS5298718A (en) |
| AT (1) | AT366989B (en) |
| BE (1) | BE851369A (en) |
| CA (1) | CA1088313A (en) |
| CH (1) | CH613175A5 (en) |
| DE (1) | DE2705618A1 (en) |
| DK (1) | DK61777A (en) |
| ES (1) | ES455876A1 (en) |
| FR (1) | FR2340911A1 (en) |
| GB (1) | GB1525683A (en) |
| IT (1) | IT1082463B (en) |
| NL (1) | NL7701453A (en) |
| NO (1) | NO141042C (en) |
| SE (1) | SE421066B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2686045A (en) * | 1949-06-28 | 1954-08-10 | Jonas J Byberg | Duster apparatus |
| FR2551746B1 (en) * | 1983-09-14 | 1986-09-05 | Saint Gobain Vitrage | PROCESS AND DEVICE FOR ELABORATING MOLTEN GLASS, AND APPLICATIONS THEREOF |
| FR2774085B3 (en) | 1998-01-26 | 2000-02-25 | Saint Gobain Vitrage | PROCESS FOR MELTING AND REFINING VITRIFIABLE MATERIALS |
| EP1568253A1 (en) * | 2002-12-03 | 2005-08-31 | Schott AG | Heating device comprising an electrode for the conductive heating of melts |
-
1976
- 1976-02-12 FR FR7603813A patent/FR2340911A1/en active Granted
-
1977
- 1977-02-10 DE DE19772705618 patent/DE2705618A1/en not_active Ceased
- 1977-02-10 SE SE7701513A patent/SE421066B/en unknown
- 1977-02-11 GB GB5725/77A patent/GB1525683A/en not_active Expired
- 1977-02-11 DK DK61777A patent/DK61777A/en not_active Application Discontinuation
- 1977-02-11 CA CA271,541A patent/CA1088313A/en not_active Expired
- 1977-02-11 NL NL7701453A patent/NL7701453A/en not_active Application Discontinuation
- 1977-02-11 CH CH169877A patent/CH613175A5/en not_active IP Right Cessation
- 1977-02-11 IT IT67323/77A patent/IT1082463B/en active
- 1977-02-11 NO NO770460A patent/NO141042C/en unknown
- 1977-02-11 AT AT0092777A patent/AT366989B/en not_active IP Right Cessation
- 1977-02-11 BE BE174893A patent/BE851369A/en not_active IP Right Cessation
- 1977-02-12 JP JP1354077A patent/JPS5298718A/en active Pending
- 1977-02-12 ES ES455876A patent/ES455876A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| NO141042B (en) | 1979-09-24 |
| FR2340911B1 (en) | 1982-05-21 |
| IT1082463B (en) | 1985-05-21 |
| ATA92777A (en) | 1981-10-15 |
| GB1525683A (en) | 1978-09-20 |
| FR2340911A1 (en) | 1977-09-09 |
| JPS5298718A (en) | 1977-08-18 |
| ES455876A1 (en) | 1978-01-16 |
| CH613175A5 (en) | 1979-09-14 |
| NO141042C (en) | 1980-01-09 |
| SE421066B (en) | 1981-11-23 |
| AT366989B (en) | 1982-05-25 |
| BE851369A (en) | 1977-08-11 |
| DE2705618A1 (en) | 1977-08-18 |
| SE7701513L (en) | 1977-08-13 |
| NO770460L (en) | 1977-08-15 |
| NL7701453A (en) | 1977-08-16 |
| DK61777A (en) | 1977-08-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |