MXPA98002602A - Float glass production facility and method - Google Patents

Abstract

A float glass production facility comprising a furnace including a melter (2), a refiner (3) and a working end (4), the working end (4) having two or more exits (6, 10), each of which supplies a separate canal (8, 13) and float glass forming chamber (9, 14), the working end (4) being operable so that the glass flow through each of the two or more exits (6, 10) is independent of the flow of glass through the other exits (6, 10).

Description

INSTALLATIONS AND FLOAT GLASS PRODUCTION METHOD The invention relates to the production of float glass. A conventional float glass production line is composed of a glass melting furnace, otherwise known as a tank, in which a batch of material is melted and the resulting fired glass is refined and conditioned, a chamber that forms the float glass, otherwise known as a bath, in which the molten glass received from the furnace is formed in a float glass band, and an annealing furnace in which the belt cools during its journey from the bath to deposit where the glass will be cut into plates and stacked. The capacity, for example of maximum performance, of said line is determined by the maximum performance of the lowest capacity part of the line, and the line may require operating at different outputs and making different products, ie different thicknesses of glass (substances), at different times. This may limit the efficient use of the furnace which may often have to operate below its capacity and the float chamber which may have to be equipped to produce a variety of products. There have been previous proposals for the feeding of a plurality of flat glass formation chambers from a simple glass melting furnace - see, for example, US Pat. 3,932,165. However, such production arrangements run the risk of impairing the quality of the glass, both with respect to discrete faults such as stones or bubbles and with respect to the overall optical quality, which with float glass generally has to be of a considerably high standard. higher than the other forms of glass including other forms of flat glass. According to the present invention, float glass production facilities have been supplied including a foundry furnace having a casting zone in which the material in batch of material is melted to form molten glass, a refining zone in which the glass cast is refined to a suitable standard for the manufacture of the float glass and a working end from which the refined glass is fed for the manufacture of float glass bands and a working end from which the refined glass is fed for the formation of strips, there being a first channel connecting the first outlet from the working end to a first float glass formation chamber and a second channel connecting a second exit of the work end to a second float glass formation chamber, in which the working end is operable in such a way that the flow of the glass through one of the outputs is independent the flow of glass through the other outlet, and the second channel has an adjacent depth the second exit such that the flow of the glass together with the channel are in a direction away from the outlet and the counterflow through the outlet returning within the working end which is impossible and has a length greater than its width sufficient to allow thermal conditioning and homogenization of the glass flowing along the second channel, associated therewith the elements of the second channel for a thermal conditioning and elements for homogenising the glass flowing along it, and a closing device for closing the flow of the glass along the second channel from the second outlet at the working end. It will be appreciated that said facilities can, in fact, provide two production lines of float glass fed from a single melting furnace which can allow a more efficient use of the furnace and of the float formation chambers and that can enable different products for be produced in the respective different lines at the same time. Preferably the second channel forces the flow of glass towards a unidirectional flow throughput in its length that there is no back flow in the second channel. This can be achieved through the appropriate depth of the second channel but could have at least a gradual change of cross section, that is, depth and / or width. The second channel can have a fold which can conveniently allow the second line to run parallel to the first. The homogenization elements associated with the second channel preferably comprise agitators which can, in particular, be supplied in the second channel near their final downstream. The first and second exits at the working end are preferably sufficiently spaced to achieve independence from the respective flows of glass flowing therethrough. However, mixers can be supplied at the working end near the first outlet to homogenize the molten glass flowing to the first outlet and thus helping to ensure such independence. The first outlet may be on one end wall and the second outlet on a side wall of the working end, the second outlet preferably located at least two thirds of the length of the side wall from the end wall. Preferably the second channel joins the second outlet substantially in the right angles of the wall of the working end containing the second outlet. All previously mentioned mixers are preferably paddle mixers. The thermal conditioning elements associated with the second channel may be composed of upper heaters or may be composed of electrodes to give effect to Joule heating or may be composed of a combination of these. The working end may have one or more future outlets additional to the first and second outlets for feeding the molten glass to one or more future float glass formation chambers, with a subsequent respective channel having characteristics similar to the second channel between each of the subsequent outputs and the respective float glass formation chamber.

The invention also provides a method of producing float glass including casting batch material to form molten glass in a single melting furnace melting zone, refining molten glass into a single melting furnace with a suitable standard for manufacturing of float glass, feeding the first flow of refined molten glass from a working end of a single melting furnace and forming this glass in a first float glass strip, feeding a second flow of refined molten glass regardless of the first flow from the end working from a single melting furnace and thermal conditioning and homogenizing the molten glass in the second flow and then forming that glass in a second float glass band. The method may include mixing the molten glass at a working end of a single melting furnace while passing within the first flow rate and may include mixing the molten glass at the second flow rate just before delivery to the chamber for the formation of The second float glass band. Surprisingly it has been found that, with facilities or method according to the invention, a number of bands each of good quality float glass can be formed from molten glass fed at the respective flow rates from the working end of a single melting furnace, even with different yields for the respective flows with asymmetrical arrangements. In order that the invention may be better understood, the modalities thereof will now be described in exemplary form, with reference to the accompanying drawings in which: Figure 1 is a schematic plan view of the part of the production facilities for float glass. Figure 2 is a schematic representation of a fold in a channel Figure 3 is a schematic sectional section showing the heating elements in a channel, Figure 4 is a schematic view showing mixers in a channel, Figure 5 is a schematic longitudinal section showing the mixers in a channel, Figure 6 is a schematic plan view of part of other float glass production facilities, Figure 1 shows a glass melting furnace 1 which is comprised of a casting zone 2, a refining zone 3 and a working end 4. The batch material is fed into the melting zone 2 in a well-known manner and is melted there to form molten glass which is then refined, i.e. the bubbles are removed, in the refining zone 3. The molten glass then passes to the working end 4 in which the conditioning of the glass is carried out. The furnace shown in Figure 1 is of a shape having a discharge 5 between the refining zone 3 and the working end 4. The mixers and the chilled water pipe can be used in or adjacent to the discharge 5 for homogenizing glass passing through it, for example in a manner as described in British Patent Specification 1503145. As is well understood in those that are well-skilled in the art, there will be no precise fixed boundaries between the casting, refining zones and conditioning of the glass melting furnace. It will be understood later that the particular shape of the furnace shown in Figure 1 is presented as a form of illustration and example only and that no other form of glass melting furnace capable of producing molten glass of a quality and refinement to a suitable standard for the Glass making float can be employed.

The working end 4, which is shown as a rectangular shape has a first outlet 6 at its outlet wall 7 through which the first flow of molten glass flows into the first channel 8, shown as tapered, by which delivery to a first floating glass formation chamber. A lift door (not shown) is provided to control, and if necessary, stop the flow of glass that is carried from channel 8. From the glass delivered the first float glass band is formed which is then led from the outlet of the formation chamber through a cooling oven (which is not shown) to a cutting room in a well-known way. The installation as described in reference to Figure 1 is a glass production line. According to the present invention, the working end 4 of the melting furnace as a second outlet 10 through which a second flow of molten glass can flow. This second outlet 10 is located 'on the side wall 11 of the working end at a distance of at least two thirds of the length of the side wall 11 from the end wall 11 from the discharge end of the working end. but preferably not immediately adjacent to the corner. The second outlet 10 is therefore well spaced from the first outlet 6 and more particularly the first and second outlets are sufficiently spaced in such a way that the interaction between the first and second glass flows respectively flow through and can be avoided and it can thus achieve the independence of the flows. If it is desired to avoid such interaction this can be done and such independence can be ensured later through the use of mixers 12 at a working end 4 near the first outlet 6 in a manner as described in British Patent Application No. 95 / 22123.0 (whose discovery is incorporated by reference) which may allow a closer spacing of the first and second outputs 6 and 10. In any case, the working end may be operated in such a way that the flow of glass to through one outlet does not affect and be independent of the flow of glass through the other. A second channel 13 connects the second outlet 10 to a second float glass formation chamber 14. This second channel 13 is a long channel in relation to the first channel 8, ie it has a length greater than its width, sufficient to allow a thermal conditioning and the homogenization of the glass flow along it as described below. The second channel 13 joins the second outlet 10 substantially at the angles to the right of the side wall 11 and has a depth adjacent to the outlet such that the flow of the glass along the channel is in a direction away from the exit and of the counterflow through the back of the outlet to the working end and is obstructed. This ensures that the molten glass at the working end will not be contaminated or adversely affected by a counterflow of the second channel 13. Preferably the second channel 13 is a single flow effectively, ie, it constricts the flow of glass to a flow of downstream in one direction, through its length. If desired, however, this may have changes in the depth but preferably these changes should be gradual to make the changes in steps in such a way as to ensure a smooth flow and avoid the creation of slow moving glass bags which It can increase the risk of glass failure. In the same way the second channel can, if desired, have changes in the width, but again these must be preferably gradual instead of shifted changes for the same reasons. In this way the changes in the cross section of the second channel can be better achieved by the tapering of the transition sections. Figure 1 shows this tapered section 15, which reduces both width and depth, near the end of the downstream of the second channel 13 where it delivers the molten glass to the second floating glass formation chamber 14. A lift door (not shown) ) is provided to control and if necessary stop the flow of the glass into the formation chamber. Since the second channel 13 is a long channel, this can suffer from a "significant" lowered ", that is to say that the level of the surface of free glass goes down together with the channel due to loss of friction pressure. This can affect the head of the glass effectively behind the lift control door and the depth of the channel needs to be sufficient to ensure that the lift gate control can be maintained. The driven glass is formed in the chamber 14 in a second float glass band which is led from the outlet of the chamber to a cooling oven (not shown) within a cutting section in a recognized manner. The second channel 13 has bent right angle 16 which enables the second float glass formation chamber 14 to run parallel to the first float glass formation chamber 9. The length of the first branch of the channel 13 between the working end and the bend 16 is sufficient to leave sufficient space between the training chambers 9 and 14 for satisfactory operation, including for example the operations of starting, inserting and removing the devices such as the upper rollers, coolers, coating equipment and the like. . The length of the second branch of the channel 13 between the bend and the forming chamber 14 is sufficient for a convenient location of the formation chamber inlet, for example it levels approximately or slightly downstream of the entrance to the first chamber 9. This provides a convenient layout of the factory with the first and second parallel lines (axes by their respective cameras, cooling oven and cutting section). In practice, with appropriate arrangements of conveyor belts, there may be some shared facilities for cutting and stacking. In order to minimize the adverse effects that arise from the flow of the glass around the bend 16, a swan neck shape is preferable as is used in other parts of the glass industry. This shape involves protrusions 17 and 18 providing a taper of about half the width within the actual fold followed by a smooth expansion back to the full width leaving the bend as shown in Figure 2. This achieves a flow of glass more symmetrical near the centerline of the channel as it is known in art. The elements of the thermal conditioning 19 are associated with the second channel 13 for conditioning the molten glass flowing therethrough. Figure 1 indicates one of these thermal conditioning elements in each branch of the channel but it should be understood that these can be located anywhere else that is required along the channel. Figure 3 shows the particular shapes of the elements of the thermal conditioning that are comprised by elevated radiant heaters 20, which can be gas or oil or electric burners, and electrodes 21 immersed in the glass flowing to give effect to the Joule heating . In practice, the elements of the thermal conditioning can be comprised by one or other of the combinations of said types of heaters. The homogenization elements 22 are also associated with the second channel 13 to homogenize the molten glass flowing therethrough. Figure 1 shows the elements of said homogenization 22 near the end of the downstream just before the tapered section 15 in the form of mixers also shown in Figures 4 and 5. The mixers 23 and 24 constitute a pair of paddle mixers. arranged to rotate in opposite directions 90 ° out of phase. The spaces between the respective mixers and between the mixers and the side walls of the channel are such that they achieve the effectiveness of the homogenization without affecting the performance. The postage between the mixers and the channel floor may be small enough to avoid significant leaks but large enough to avoid mechanical contact or severely accelerated correction of the channel bottom. The blades or blades in the mixers must be completely submerged in the glass in such a way that only the axes break the free glass surface, the tips of the blades being sufficiently low to avoid the entry of bubbles or the generation of excessive swell but significantly close to this to obstruct leakage of unmixed glass over the blades. The mixers should preferably not be water cooled so as not to have heavy cooling effects in the devitrification of the glass, but they can be made of resistant refractory ceramic, the refractory shapes coated with a noble metal, or a refractory metal alloy. . Although Figure 1 indicates that the mixers are only near the end of the downstream of the second channel 13, these can be located in other positions along the channel as required. A shutoff device 25, analogous to the liftgate, is provided as indicated in Figure 1 at the entrance of the second channel 13 to cut off the flow of the glass along the second channel from the second outlet at the service end 4. The device 25 is preferably located as close as possible to the side wall 11 containing the outlet 10 in such a way as to minimize the amount of glass between the outlet 10 and the device 25, and the device 25 is preferably cooled by water to freeze adjacent glass when in the off position. This device 25 can be used to stop the flow of the glass in the second channel 13, when, for any reason, the second float formation chamber is not operating.

The manner of operation of the facilities will be broadly apparent from the foregoing. The glass batch is melted to form molten glass in a melting zone 2 of a single melting furnace 1 and the molten glass is refined in the refining zone 3. When both lines are in operation a first flow of refined molten glass is fed from the first outlet 6 of the working end of a single melting furnace and formed by forming a first strip of float glass in the first formation chamber 9 while a second independent flow of refined melted glass is fed from the second outlet 10 of the end working from a single melting furnace. The molten glass in the second flow is thermally conditioned and homogenized while traveling together with the second channel 13 and then formed in a second float glass band in the second forming chamber 14. If desired the molten glass passing in the First flow can be mixed by mixers 12 at the working end just before delivery to the first training chamber. The molten glass in the second flow can be mixed at the end of the downstream of the long channel 13 just before delivery to the second forming chamber 14.

Training chambers 9 and 14 can be operated to make different products at the same time. For example one may have coating equipment to make a coated product while the other makes uncoated glass. Different thicknesses (substances) and / or band widths can be produced. The additives for the base glass can be injected into the second channel. Subsequently, through adjustments to the right product mix, the only melting furnace can operate at almost constant production (loading) allowing greater efficiency and cost advantages, optimizing the design of the furnace and improving the basic quality of the glass. If it is necessary to shut down the first line, this can be done through the liftgate in the delivery to the first training chamber 9. If it is required to turn off the second line, this can be done by operating the shutdown device 25 (and from there virtually insulating all the glass in the second channel 13 from the working end 4 which is preferable to close by means of a lift door in the delivery to the second forming chamber 14). It would be appreciated if the facilities according to the invention were built in a new plant or extensions could be made to an existing plant. As shown in the embodiment of Figure 1, it can be achieved by increasing a second channel 13 and a second float formation chamber 14 to an existing plant which is composed of a melting furnace 1, the first channel 8 and the first chamber of float formation 9. In this case the mixers 12 at the working end near the first outlet 6 can be highly desirable and if necessary the capacity of the existing melting furnace 1 can be increased through the application of raising the heating as well as raising its performance to satisfy both lines. It will be understood below that the dimensions and operating parameters of the second channel will be chosen to meet the particular requirements of the plant. This choice is within the capabilities of those qualified in the art, possibly with some judgment and experimentation, and the following information, is based largely on a working model, which is presented as a form of illustration and example for guidance only. The second channel should generally have a length greater than four meters and should typically be longer, for example forty meters or more. In the embodiment of Figure 1, for example, the second channel may have a first branch of about 22 meters towards the bend 16 and a second branch also of almost 22 meters from the bend 16 towards the downstream end, giving a total of about 44 meters. The width of the glass conveyor belt of the second channel 13 can be almost two meters becoming narrower to almost one meter at its downstream end when delivering the glass into the second forming chamber 14, the length d the tapered section 15 being almost one meter. In the swan neck fold 16 the width of the glass conveyor belt is also reduced to almost one meter. The ratio of the curvature of the inner and outer projections 17 and 18 can be about 300 mm and 1300 mm respectively around the same center C, the other dimensions of the inner projections 17 shown as A and B in Figure 2 would be about one meter and 600 mm respectively. The depth of the glass in the second channel 13 just upstream of the tapered section 15 can be about 500 mm reducing to about 300 in the downstream of the tapered section 15. As mentioned above, the cutting phenomenon means that the depth of the glass may be higher at the upstream end of the channel 13 but preferably the loss of the head shall not exceed 10% of the depth of the glass in the control liftgate such that, with the present example , the depth of the glass at the upstream end of the channel 13 is about 530 mm. As also explained above, this depth is such that the flow is unidirectional and the counterflow within the working end 4 through the second outlet 10, is avoided, said uni-flow also improves the stability of the process. The vane mixers 23 and 23 near the end of the downstream of the second channel 13 are preferably rotated relatively slowly, for example at around 6 rpm and 20 rpm to avoid the introduction of bubbles and to avoid a "blockage", is say, when the net resistance of the loose becomes excessive and the glass tends to flow on or under the mixers instead of between them, but fast enough to ensure a complete homogenization. The width of the blades for each mixer is as shown in Figure 4 but it is preferable that they are between 20% and 25% of the width of the channel, for example, about 450 mm, the mixers are mounted symmetrically near the centerline of the channel with a spacing between the axis of the mixer centered between about 35% to 40% of the width of the channel, for example, almost 760 mm. The edges of the nearest blades enter the side walls of the channel, in operation it is preferable that they are at about 16% and 23% of the width of the channel, for example, about 395 mm. The postage between the bottom of the mixer blades and the channel floor can be between about 5% and 20% glass depth, ie about 60 mm. The floor of the canal can be built with refractory resistant to corrosion or have a double protection with noble metals to allow a small postage without introducing refractory corrosion faults which could severely impair good quality. The shafts of the mixer can be located about 1200 mm upstream of the upstream end in the tapered section 15, this being in practical terms just before delivery of the molten glass to the forming chamber 14. The second channel 13 is designed and operated to prevent the introduction into the second flow of molten glass discrete faults that could otherwise arise for example from devitrification, stagnant or semi-stale glass, contamination with refractory corrosion products, or events occurring in the joints between refractory glass contact blocks. However, the depth of the glass in the channel is such that a uni-flow in the operation is achieved and prevents the flow of the glass back to the working end of the melting furnace from any of the faults that could be transmitted to the first caudal. The elements of the thermal conditioning 19 serve to ensure that the required temperature conditions are maintained in the glass flowing along the second channel 13., including a desirable surface temperature and acceptable temperature differences from side to side or from one side to the center and from top to bottom. The temperature control can also be helped by a judicious use of insulation, particularly around the lower level of the structure of the glass in the bottom of the channel. The glass entering the second channel 13 through the second outlet 10 can, as an example of the conventional float glass composition, be at a temperature between about 1160 ° C and 1190 ° C. It can be maintained in the first part of the channel at a surface temperature of about 1180 ° C which can be reduced to about 1170 ° C at bend 16. Between bend 16 and the end of the downstream channel glass can be gradually cooled in a controlled manner to a glass surface temperature of about 1100 ° C at the delivery to the lift gate of the formation chamber 14. The temperature differences from side to side which may be around 13 ° C at the entrance of channel 13 can be reduced to a side-to-center deference of about 8 ° C or less and the temperature difference of the surface to the bottom can be around 15 ° C. The production (loading) of the glass melting furnace 1 can for example be around 7000 tons per week (tps) with the first line of the float incorporating the first formation chamber 9 operating at around 4000 tps and the second line of the float incorporating the second training chamber 14 operation at around 3000 tps. It will also be appreciated that more two lines are taken from a single glass melting furnace, the end in service of the furnace is supplied with the required number of outlets or being operated in such a way that the flow of the glass through any of the outputs do not affect the flow of the glass through any of the other outlets, where the independent glass flows can be achieved, and having respective channels having characteristics similar to those described for the second channel connecting the additional outputs to the glass formation chambers respective float. Figure 6 shows installations with three lines. The arrangement of the first and second lines is essentially the same as in Figure 1 and the same reference number is used to indicate the same parts. The third line is basically similar to the second line and is indicated by the same numerical reference as the second line but with the suffix A. In this way the third line is fed from a third outlet 10A on the side wall HA of the working end 4 opposite the side wall 11. A third long channel 13A having a swan neck bend 16A and having associated thermal conditioning elements 19A (shown after bending only) and homogenizing elements 22A near its downstream end. which has a tapered section 15A, connects the third outlet 10A to a third float glass formation chamber 14A. The shutdown device 25A on the third channel 13A adjacent to the third outlet 10A can be operated to close the flow of glass to that channel. When this device is opened the refined molten glass flows as a third flow along the uni-flow channel 13A to the forming chamber 14A in which it is formed in a third float glass band. The separation of the respective outlets 6, 10 and 10A at the working end and the use of mixers 12 adjacent to the first outlet 6 cancels the interaction between the glass flows flowing through the respective outlets and ensures their independence. Figure 6 also shows a modification or addition of cells 26 and 26A located in the branches of the upstream from the second and third long channels 13 and 13A respectively. These cells can be operated to modify the molten glass flowing through the channel, for example when injecting additive material to alter its color or composition. With said cells the float glasses produced in the second and third lines may have properties different from those of the first line, which uses the standard glass base unmodified from the working end 4, and start from each one. "The installations can therefore simultaneously manufacture three float bands not only with different thicknesses and / or widths but also with different composition or properties, if one or more of the float formation chambers are desired, they can be supplied with coating installations for coating the float band passing through it The glass melting furnace 1 can, for example, operate at around 12,000 tps with the first float line operating at around 8,000 tps, the second float line around 1000 tps and the third float line at around 3000 tps In the embodiments of Figures 1 and 6 the working end 4 of the glass melting furnace is of a conventional rectangular shape with outputs provided in the end wall and length of the lateral wall (s), for example, of the order of 15 meters, It will be understood that if more than three lines are taken for a single smelting furnace, then The working end may need to have a different geometry, for example, in a polygonal or semicircular shape, to allow the respective channels to join it and maintain the independence of the glass flows flowing in. The modalities of Figures 1 to 6 have parallel lines which is normally convenient for factory layout. It will be understood, however, that in particular circumstances they require or can tolerate lines in another angular relationship, for example, in the angles from right side to another, this can be achieved by omitting the bend in the relevant channel or having the bend in a different angle. Subsequent variations of the specifically described embodiments which can be made without departing from the principles of the invention will be immediately apparent to those skilled in the art. For example, where a single pair of mixers 23 and 24 are shown through the second channel 13, there could be two or more mixer pairs, or a non number of mixers across the width of the channel, the dimension guide is presented above is properly fractioned. The mixers can be located in a plurality of places along the second channel 13, the locations should be sufficiently spaced to avoid adverse interaction. While a simple pair of mixers in each location is preferable, although there could be more, as explained above. It will be understood that long channel homogenization is necessary, at least near the end of the downstream, to remove elliptical broadening characteristics which may impair the optical quality of the product and to remove temperature variations from side to side. which can damage the uniformity of the thickness of the product and surprisingly this can be achieved by mixing in the channel to give a good quality float glass in the second band. Similarly, more than two mixers can be supplied at the working end 4 near the first outlet 6 although a single pair is preferable. It will be understood that while under a favorable design, the composition of the glass and the melting conditions, these mixers may be unnecessary, may be useful to protect the first line of quality disabilities which may otherwise arise due to the change of the conditioning flow patterns resulting from the secondary line (s), that is, to provide the operable working end to achieve independent glass flows in such a way that the flow of glass through a of the outlets does not affect the flow of the glass through another outlet (s). It will be appreciated that the facilities for production of float glass with plural lines running from a single melting furnaceEach one capable of producing good quality float glass has considerable benefits in enabling an efficient operation of the melting furnace while producing a desirable float glass product mix. One (the main) line can be used for the manufacture of standard clear float glass with popular widths and thicknesses, the melting furnace producing said clear float glass, while the other or other lines are used to produce widely used products. For example, one can create colored float glass through the addition of coloring material in its respective channel, for this also the color adjustments are enabled for a quick elaboration. A first line, particularly the float formation chamber, may be specifically designed for the production of a particular product, such as thin glass or coated glass, and there are many provisions for selective modification of the products made in a line in particular at different times to direct them in the short term to specialized markets.

Claims (16)

1. Claims 1. Facilities for the production of float glass are comprised of a foundry furnace including a casting zone in which a batch of material is melted to form molten glass; a refining zone in which the molten glass is refined to have a suitable standard for the manufacture of float glass; a working end to condition the refined glass, the working end having an outlet delivering the molten glass into a channel and a floating glass formation chamber receiving the channel glass; characterized at the working end (4) there is a rear exit (10) leading to a second channel (13), delivering the molten glass into the second float glass formation chamber (14); where the working end (4) is operable in such a way as to cause the glass flow through the two outlets (6, 10) to be independent of each other, the second channel (13) having a depth adjacent to the second outlet (10) that the glass flow along the second channel (13) is in a direction away from the second outlet (10) and the counterflow through the second outlet (10) towards the working end ( 4) is obstructed, the length of the second channel (13) is greater than the width of the same in such a way that the thermal conditioning and homogenization of the glass flowing along the second channel (13), the facilities may subsequently include elements of thermal conditioning and supplementary homogenization (19, 22) associated with said second channel (13) and closing elements (25) to close the flow of the glass along the second channel (13) from the second outlet (10) at the end of work (4). The installations according to Claim 1 characterized in a second channel (13) reduces the flow of the glass towards a unidirectional flow through the length of the channel (13). The installations according to Claim 1 or Claim 2 which are characterized as the second channel (13) have at least a gradual change of the cross section (15, 17, 18). Facilities according to any of the Claims 1 through 3 characterized in that the second channel (13) has a fold (16) formed therein. Installations according to any of the preceding Claims in which are characterized by the homogenization elements (22) associated with the second channels and containing mixers (23, 24). Installations that according to Claim 5 wherein are characterized by the mixers (23, 24) in the second channel being near the end of the downstream stream. Installations according to any of the previous Claims in which the mixers (12) are supplied at the working end (4) near the first outlet (6). Installations where any of Claims 5, 6 and 7 are characterized in that the mixers (12, 23, 24) are paddle mixers. Installations according to any of the preceding Claims characterized in that the thermal conditioning elements (19) associated with the second channel (13) include elevated heaters (20). .A facilities that according to any of the Previous claims characterized in that the thermal conditioning elements (19) associated with the second channel (13) include electrodes (21) to effect the Joule heating of the glass. An installation according to any of the preceding Claims characterized in that the first and second exits (5, 10) at the working end (4) are sufficiently spaced to achieve the independence of the respective glass flows flowing through these. .A facilities according to any of the Previous claims in which they are characterized by the fact that the first outlet (6) are in an end wall (7) and the second outlet (10) in a side wall (11) of the working end (4). . Installations according to Claim 12, characterized in that the second outlet (10) is located at least two thirds of the length of the side wall (11) from the end wall (7). An installation according to any of the preceding Claims characterized in that the second channel (13) joins the second outlet- (10) substantially at the angles of the right side of the wall of the working end (11) containing a second exit (10). An installation according to any one of the preceding Claims characterized in that the working end (4) has a subsequent exit or further exits (10A) to the first and second exits (6)., 10) to feed the molten glass to a rear float glass forming chamber or subsequent float glass formation chambers (14A), there being a channel (13A) having characteristics similar to those of the second channel (13) between each of the rear outlets (10A) and the respective float glass formation chamber (14A). 16. A method of producing float glass including a batch of material to form molten glass in a melting zone (2) from a single melting furnace (1), by retreating (3) the molten glass in a single melting furnace- to a suitable float glass manufacturing standard, the first flow of the refined molten glass fed from a working end of the single melting furnace and forming that glass into a first float glass band characterized by feeding the second refined molten glass stream independently of the first flow from the working end (4) of the single melting and thermal conditioning furnace and homogenizing the molten glass in the second flow and then forming that glass in a second float glass band. A method according to Claim 16 characterized by glass mixed at the working end (4) of a single melting furnace (1) while passing within a first flow. A method according to Claim 17 or Claim 18 characterized by the mixing of molten glass in a second flow just prior to delivery to the forming chamber (14) within the second float glass band.