Process and device for melting and fining glass

Abstract

The invention relates to a process and a device for manufacturing molten glass comprising from upstream to downstream a furnace for melting and fining glass equipped with cross-fired overhead burners, then a conditioning basin supplied with glass by the furnace, the dimensions of this manufacturing device being such that K is higher than 3.5, the factor K being determined from the dimensions of the device. The invention makes it possible to dimension a device for melting glass so that it is smaller and consumes less energy while producing high quality glass.

Claims

1. A process for manufacturing molten glass in a device comprising, from upstream to downstream, a furnace for melting and fining glass equipped with cross-fired overhead burners, and then a conditioning basin comprising one or more compartments, the process comprising melting glass in the furnace, wherein: the furnace comprises a melting zone and a fining zone; the bottom of the fining zone and the bottom of the conditioning basin are deep enough that a single downstream recirculation loop passes through the fining zone and through all the compartments of the conditioning basin; the conditioning basin is supplied with glass by the furnace; and the dimensions of the device are such that K is higher than 3.5, where: $K = K_{a} + \underset{i}{.Math.} K_{S_{i}},$ in which: $K_{a} = 0.000727 S_{f}_{x_{0}}^{x_{1}} \frac{{[P (x)]}^{2}}{{[(x)]}^{3}} dx;$ S.sub.f represents the area under flame in the furnace; x.sub.0 is the abscissa in the general flow direction of the glass of the end of the area under flame in the furnace; x.sub.1 is the abscissa in the general flow direction of the glass of the end of the conditioning basin; (x) represents the area of the cross section of flow of the glass of the device at the abscissa x; P(x) represents the perimeter of the cross section of flow of the glass of the device at the abscissa x; and .sub.iK.sub.Si represents the sum of the K.sub.Si due to a singular element in the device downstream of the area under flame in the furnace, a singular element producing, from upstream to downstream and over less than 2 m in the flow direction of the glass, a decrease in the cross section of flow of the glass of more than 10% then an increase in the cross section of flow of the glass of more than 10%, where $K_{S_{i}} = 0.0012 (\exp [5.16 {(\frac{_{i} -_{S_{i}}}{_{i}})}^{2.55}] - 1) {(\frac{S_{f}}{_{i}})}^{2};$ .sub.i representing the area of the cross section of flow of the glass just upstream of the singular element S.sub.i; and .sub.Si representing the area of the minimum cross section of flow produced by the singular element S.sub.i.

2. The process of claim 1, wherein K>5.5.

3. The process of claim 2, wherein K>7.5.

4. The process of claim 3, wherein K is higher than 9.

5. The process of claim 1, wherein a ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.4.

6. The process of claim 5, wherein the ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.6.

7. The process of claim 6, wherein the ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.8.

8. The process of claim 1, wherein the furnace is sufficiently deep that an upstream recirculation loop and the downstream recirculation loop form in the furnace.

9. The process of claim 1, wherein the conditioning basin comprises, from upstream to downstream, a neck then a working end.

10. The process of claim 1, wherein the furnace has a capacity of 500 to 1500 m.sup.3 of glass.

11. The process of claim 1, having a pull of 400 to 1300 tonnes of glass per day.

12. The process of claim 1, wherein the cross-fired overhead burners use an oxidant comprising 10 to 30 vol % O.sub.2, and are equipped with regenerators and function pairwise in reversal mode.

13. The process of claim 1, wherein the cross-fired overhead, burners use an oxidant containing 80 to 100 vol % O.sub.2.

14. The process of claim 1, wherein in the conditioning basin in any vertical plane transverse to the longitudinal axis of the furnace, there are points in the glass having a longitudinal velocity component pointing from downstream to upstream.

15. The process of to claim 1, wherein after the conditioning basin, the glass passes into a channel itself supplying a forming device, with no backflow occurring in the channel.

16. The process of claim 15, wherein a length of the channel ranges from 0.3 to 10 m.

17. A process for manufacturing flat glass, the process comprising manufacturing a molten glass with the process of claim 1, and then forming the molten glass into flat glass by floating the molten glass on a molten metal bath in a float chamber.

18. A device for manufacturing molten glass, the device comprising, from upstream to downstream, a furnace for melting and fining glass equipped with cross-tired overhead burners, and then a conditioning basin comprising one or more compartments, wherein: the furnace comprises a melting zone and a fining zone; the bottom of the fining zone and the bottom of the conditioning basin are deep enough that a single downstream recirculation loop passes through the fining zone and through all the compartments of the conditioning basin; the conditioning basin is supplied with glass by the furnace; and the dimensions of the device are such that K is higher than 3.5, where: $K = K_{a} + \underset{i}{.Math.} K_{S_{i}},$ in which: $K = 0.000727 S_{f}_{x_{0}}^{x_{1}} \frac{{[P (x)]}^{2}}{{[(x)]}^{3}} dx;$ S.sub.f represents the area under flame in the furnace; x.sub.0 is the abscissa in the general flow direction of the glass of xe end of the area under flame in the furnace; x.sub.1 is the abscissa in the general flow direction of the glass of xe end of the conditioning basin; (x) represents the area of the cross section of flow of the glass of the device at the abscissa x; P(x) represents the perimeter of the cross section of flow of the glass of the device at the abscissa x; and .sub.iK.sub.Si represents the sum of the K.sub.Si due to a singular element in the device downstream of the area under flame in the furnace, a singular element producing, from upstream to downstream and over less than 2 m in the flow direction of the glass, a decrease in the cross section of flow of the glass of more than 10% then an increase in the cross section of flow of the glass of more than 10%, where $K_{S_{i}} = 0.0012 (\exp [5.16 {(\frac{_{i} -_{S_{i}}}{_{i}})}^{2.55}] - 1) {(\frac{S_{f}}{_{i}})}^{2};$ .sub.i representing the area of the cross section of flow of the glass just upstream of the singular element S.sub.i; and .sub.Si representing the area of the minimum cross section of flow produced by the singular element S.sub.i.

19. The device of claim 18, wherein K>5.5.

20. The device of claim 19, wherein K>7.5.

21. The device of claim 20, wherein K is higher than 9.

22. The device of claim 18, wherein a ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.4.

23. The device of claim 22, wherein the ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.6.

24. The device of claim 23, wherein the ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.8.

25. The device of claim 18, wherein a ratio of the area under flame in the furnace to the area of the conditioning basin is lower than 4.

26. The device of claim 18, wherein the furnace is deep enough that an upstream recirculation loop and the downstream recirculation loop form in the furnace.

27. The device of claim 18, wherein the conditioning basin comprises, from upstream to downstream, a neck then a working end.

28. The device of claim 18, wherein the furnace has a capacity of 500 to 1500 m.sup.3 of glass.

29. The device of claim 18, having a pull of 400 to 1300 tonnes of glass per day.

30. The device of claim 18, wherein the cross-fired burners use an oxidant comprising 10 to 30 vol % O.sub.2, and are equipped with regenerators and function pairwise in reversal mode.

31. The device of claim 18, wherein in the conditioning basin in any vertical plane transverse to the longitudinal axis of the furnace, there are points in the glass having a longitudinal velocity component pointing from downstream to upstream.

32. The device of claim 18, wherein after the conditioning basin, a glass being manufactured passes into a channel itself supplying a forming device, with no backflow occurring in the channel.

33. The device of claim 32, wherein a the length of the channel ranges from 0.3 to 10 m.

34. A device for manufacturing flat glass, the device comprising the device of claim 18, and a float chamber in which a molten glass is floated on a molten metal bath.

35. The device of claim 18, further comprising, over its entire length, tank blocks containing the molten glass, wherein glass height is a distance between the upper level of the tank blocks decreased by a safety margin of between 30 and 130 mm and the level of the bottom.

36. The process of claim 3, wherein K is higher than 10.5.

37. THE process of claim 1, wherein: K>5.5; a ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.4; the furnace is sufficiently deep that an upstream recirculation loop and the downstream recirculation loop form in the furnace; in the conditioning basin in any vertical plane transverse to the longitudinal axis of the furnace, there are points in the glass having a longitudinal velocity component pointing from downstream to upstream; and after the conditioning basin, the glass passes into a channel itself supplying a forming device, with no backflow occurring in the channel.

38. The device of claim 20, wherein K is higher than 10.5.

39. The device of claim 18, wherein: K>5.5; a ratio of the area under flame in the furnace to the area of the conditioning basin is higher than 1.4; the furnace is deep enough that an upstream recirculation loop and the downstream recirculation loop form in the furnace; in the conditioning basin in any vertical plane transverse to the longitudinal axis of the furnace, there are points in the glass having a longitudinal velocity component pointing from downstream to upstream; and after the conditioning basin, a glass being manufactured passes into a channel itself supplying a forming device, with no backflow occurring in the channel.

Description

(1) The figures described below are not to scale.

(2) FIG. 1 shows a device according to the invention, in a) as seen from above and in b) as seen from the side. It comprises from upstream to downstream a furnace 1, which comprises a zone for introducing raw materials 20, a melting zone 2, a fining zone 3 and a conditioning basin comprising a neck 4 and a working end 5. The working end delivers molten glass at an appropriate temperature to the forming unit via the channel 6 inside of which the flow of the glass is a plug flow. The melting/fining furnace 1 is equipped with cross-fired overhead burners, six air inlets of which are shown referenced 7. The two lateral walls 11 and 12 are equipped symmetrically with facing cross-fired burners, these burners being operated in alternation or in reversal mode, as is known in the art. The exterior limits of the four outermost air inlets (8, 9) form the corners of the quadrilateral 10, hatched in a), representing, as seen from above, the area under flame or S.sub.f. The letter x.sub.0 indicates the abscissa of the end of the area under flame in the furnace (downstream side of the quadrilateral representing the area under flame) and the letter x.sub.1 indicates the abscissa of the end of the conditioning basin, on the median longitudinal axis AA of the device (A being upstream and A being downstream) which corresponds to the general flow direction of the glass. Under the level of the surface of the molten glass 13 turn two convection cells 14 and 15. The first 14, called the upstream recirculation loop, is relatively intense in the melting compartment and especially passes under the first upstream burner 9. The second 15, called the downstream recirculation loop, is less intense and passes through the fining zone of the furnace, then through the neck and the working end, but does not pass into the channel 6. An obstruction 16 here reinforces the boundary between, and formation of, the two convection cells 14 and 15. The passage from the furnace to the neck is accompanied by an abrupt decrease in the width and in the cross section of flow of the glass, here achieved with walls 19 and 19 making an angle of 90 to the median flow direction of the glass. The passage from the neck to the working end is accompanied by an abrupt width increase in the cross section of flow of the glass, here achieved with walls 18 and 18 forming an angle of 90 with the median flow direction of the glass. A lowerable barrier 17 at the start of the neck decreases the cross section of glass flow and forms a singular element the K.sub.Si of which should be calculated. The surface of the glass 60 in the working end, i.e. the surface making contact with the atmosphere in the working end, is subject to air blown into the latter in order to cool the glass. This air passes from the working end into the conditioning device but as much as possible does not enter into the melting/fining furnace.

(3) FIG. 2 shows, seen from above, the passage from the fining zone 21 of a furnace to the conditioning basin, which is made up of a neck 22 then a working end 23. The arrows on the median longitudinal axis AA symbolise the flow of the glass from upstream to downstream. The device is symmetric on either side of the axis AA. On passing from the furnace to the neck the width of the flow of the glass is abruptly decreased by furnace walls 24 and 24 making an angle with the flow direction of the glass of at least 40 on either side of the axis AA of the device. On passing from the neck to the working end, the width of glass flow is clearly increased by way of walls 25 and 25 making an angle of more than 40 to the flow direction of the glass. This increase occurs on either side of the median longitudinal axis of the device.

(4) FIG. 3 shows a step 30 that clearly decreases the cross section of flow of the glass, the surface of which is referenced 31 and the flow direction of which is shown by arrows, said step possibly being located in a conditioning basin and in particular in a neck or working end. This is a singular element the K.sub.S of which should be calculated. The singular element starts at the point 32 (it is a point in the figure but in fact it is of course a line perpendicular to the general direction of flow of the glass) where a wall 33 making an angle of greater than 40% to the general flow direction of the glass starts to decrease the cross section of flow. The singular element ends at the point 34 at the location where a wall 35 making an angle of greater than 40% to the general flow direction of the glass finishes increasing the cross section of flow of the glass. The distance between the point 32 and the point 34 is smaller than 2 m parallel to the general flow direction of the glass shown by the horizontal arrows. This step is the cause of a minimal cross section 36 of glass flow.

(5) FIG. 4 shows a lowerable barrier 40 submerged in the glass, the surface of which is referenced 41, and the flow direction of which is shown by arrows, said barrier possibly being located in a conditioning basin and in particular in a neck or working end. This is a singular element the K.sub.Si of which should be calculated. The singular element starts at the point 42 where a wall 43 making an angle of greater than 40 to the general flow direction of the glass starts to decrease the cross section of flow of the glass. The singular element ends at the location of the point 44 where a wall 45 making an angle of greater than 40 to the general flow direction of the glass finishes increasing the cross section of flow of the glass. The distance between the point 42 and the point 44 is smaller than 2 m parallel to the general flow direction of the glass shown by the horizontal arrows. This barrier is the cause of a minimal cross section 46 of glass flow.

(6) FIG. 5a) shows a cross-sectional plane through the device orthogonal to the flow direction of the glass at an abscissa x. It may especially be a cross section through the neck or working end. The glass 50 flows orthogonally to the plane of the figure. The glass is contained by the bottom 51 and the tank blocks 52 and 52, which bottom and tank blocks form part of the substructure of the device. A barrier 53 is submerged in the glass over only some of the distance between the tank blocks, in the plane of the cross section of flow of the glass. The system maintaining the barrier is not shown, nor is the roof covering the interior of the device. The glass level 55 making contact with the internal atmosphere is located below the upper level 56 of the tank blocks by a distance 57 called a safety margin. The elements 54 and 54 are borne by the tank blocks and form part of the superstructure. FIG. 5b) explains what is meant by the expressions area of the cross section of flow of the glass at the abscissa x and perimeter of the cross section of flow of the glass of the device at the abscissa x, as applied to the case in FIG. 5a). The area of the cross section of flow of the glass is the area of the hatched zone in FIG. 5b). The perimeter of the cross section of flow of the glass is the sum of the length of the segments AB, BC, CD, DE, EF, FG, GH and HA.

EXAMPLES 1 TO 19

(7) All the examples were carried out in a device such as shown in FIG. 1 and comprising a melting/fining furnace followed by a conditioning basin made up of a neck followed by a working end. Tables 1 and 2 give the dimensions of the various elements of the device and the results. All the furnaces of the examples had an area under flame S.sub.f of 326.3 m.sup.2. All the examples were intended to provide a pull of 900 tonnes per day of molten glass, the maximum surface temperature of the glass in the furnace was 1590 C. and the temperature at the outlet of the working end was 1130 C. The glass was standard soda-lime glass with a content by weight of 700 ppm Fe.sub.2O.sub.3 and 180 ppm FeO. In all the examples except Examples 5, 8 and 19, a 50 mm-thick barrier maintained by the superstructure of the neck and submerged in the glass over a depth of 400 mm was placed in the neck so that the upstream face of this barrier was located 3.2 meters from the inlet of the neck. In the case of Example 5, there was no barrier (K.sub.s=0). For Example 8, the barrier was submerged in the glass to a depth of 350 mm. For Example 19, the barrier was submerged in the glass to a depth of 500 mm. Where appropriate, the barrier was the only singular element for which it was necessary to calculate a K.sub.Si.

(8) For all the examples:

(9) the length of the melting zone was 26 675 mm;

(10) the width of the melting and fining zones was 13 000 mm;

(11) the length of the fining zone was 17 000 mm;

(12) the distance between the end of the area under flame and the inlet of the neck was 14 075 mm;

(13) h.sub.f represents the glass height in the melting zone;

(14) h.sub.a represents the glass height in the fining zone;

(15) V.sub.fa represents the volume of glass in the furnace;

(16) L.sub.c represents the length of the neck;

(17) I.sub.c represents the width of the neck;

(18) h.sub.c represents the glass height in the neck;

(19) L.sub.b represents working end length;

(20) I.sub.b represents working end width;

(21) h.sub.b represents the glass height in the working end;

(22) Q represents the quality of the glass relative to the quality of the glass of Example 1 (reference case) i.e. the difference between the quality of the glass of the Example i in question and the quality of the glass of Example 1, the sum being divided by the quality of Example 1 Q=(Q.sub.iQ.sub.1)/Q.sub.1; it is the average time spent at above 1400 C. that is considered. This Q is multiplied by 100 in Table 1 in order to express the result in percent;

(23) Conso represents the energy consumption of the entire device relative to the consumption of Example 1, i.e. the difference between the consumption of the Example i in question and the consumption of Example 1, the sum being divided by the consumption of Example 1: Conso=(Conso.sub.iConso.sub.1)/Conso.sub.1; this Conso is multiplied by 100 in Table 1 in order to express the result in percent; and

(24) Souff represents the intensity of blown cooling of the working end relative to the intensity of blown cooling of the working end of Example 1, i.e. the difference between the intensity of blown cooling of the working end of the Example i in question and the intensity of blown cooling of the working end of Example 1, the sum being divided by the intensity of blown cooling of the working end of Example 1: Souff=(Souff.sub.iSouff.sub.1)/Souff.sub.1; this Souff is multiplied by 100 in Table 2 in order to express the result in percent.

(25) TABLE-US-00001 TABLE 1 h.sub.f h.sub.a V.sub.fa L.sub.c l.sub.c h.sub.c L.sub.b l.sub.b h.sub.b Q Conso Ex No. (m) (m) (m.sup.3) (m) (m) (m) (m) (m) (m) K (%) (%) 1 1.45 1.45 823 7 4.8 1.45 17 12 1.45 2.31 0 0.0 2 1.45 1.45 823 7 4.8 1.45 12.75 9 1.45 2.35 7 1.8 3 1.45 1.27 783 7 4.8 1.27 12.75 9 1.27 3.63 3 1.2 4 1.45 1.27 783 7 4.8 1.27 12.75 9 0.89 5.07 11 3.5 5 1.45 1.27 783 7 4.8 0.89 12.75 9 0.89 5.67 12 4.1 6 1.45 1.27 783 7 6.5 0.89 12.75 9 0.89 8.50 23 6.9 7 1.45 1.27 783 7 4.8 1.27 12.75 9 0.6 9.86 28 8.2 8 1.45 1.27 783 7 4.8 0.89 12.75 9 0.89 10.01 26 7.4 9 1.45 1.27 783 4.5 4.8 0.89 12.75 9 0.89 11.46 31 8.6 10 1.45 1.27 783 7 4.8 0.89 12.75 13 0.89 11.65 31 8.3 11 2 2 1136 7 4.8 0.89 12.75 9 0.89 12.02 28 7.2 12 1.45 1.45 823 7 4.8 0.89 12.75 9 0.89 12.26 27 8.5 13 1.45 1.27 783 7 4.8 0.89 12.75 9 0.89 12.45 28 8.4 14 2 1.27 974 7 4.8 0.89 12.75 9 0.89 12.45 28 7.5 15 1.27 1.27 721 7 4.8 0.89 12.75 9 0.89 12.45 27 9.3 16 1.45 0.89 700 7 4.8 0.89 12.75 9 0.89 13.51 32 8.9 17 1.45 1.27 783 7 4.8 0.89 12.75 4.8 0.89 15.17 36 9.1 18 1.45 1.27 783 7 3.7 0.89 12.75 9 0.89 18.22 36 9.7 19 1.45 1.27 783 7 4.8 0.89 12.75 9 0.89 21.76 41 9.9

(26) The values of K.sub.a and of K.sub.S due to the lowerable barrier (where K=K.sub.a+K.sub.S), the conditioning basin area characteristics and the blowing characteristics are detailed in Table 2, .sub.sc representing the minimal cross section of flow of the glass produced by the barrier in the neck (by way of singular element), S.sub.c representing the area of glass making contact with the atmosphere in the neck, S.sub.b being the area of glass making contact with the atmosphere in the working end, S.sub.cond representing the area of the glass making contact with the atmosphere in the conditioning basin (where S.sub.cond=S.sub.c+S.sub.b), and S.sub.f/S.sub.cond representing the ratio of the area under flame to the area of glass making contact with the atmosphere in the conditioning basin.

(27) TABLE-US-00002 TABLE 2 Ex No. Ka .sub.sc (m.sup.2) K.sub.s K S.sub.c (m.sup.2) S.sub.b (m.sup.2) S.sub.cond (m.sup.2) S.sub.f/S.sub.cond Souff (%) 1 1.75 5.04 0.56 2.31 33.6 204 237.6 1.37 0 2 1.79 5.04 0.56 2.35 33.6 114.75 148.35 2.20 119 3 2.55 4.176 1.07 3.63 33.6 114.75 148.35 2.20 83 4 4.00 4.176 1.07 5.07 33.6 114.75 148.35 2.20 55 5 5.67 4.272 0 5.67 33.6 114.75 148.35 2.20 46 6 4.84 3.185 3.65 8.50 45.5 114.75 160.25 2.04 14 7 8.78 4.176 1.07 9.86 33.6 114.75 148.35 2.20 7 8 5.73 2.592 4.29 10.01 33.6 114.75 148.35 2.20 11 9 4.77 2.352 6.70 11.46 21.6 114.75 136.35 2.39 17 10 4.96 2.352 6.70 11.65 33.6 165.75 199.35 1.64 38 11 5.32 2.352 6.70 12.02 33.6 114.75 148.35 2.20 0 12 5.56 2.352 6.70 12.26 33.6 114.75 148.35 2.20 6 13 5.75 2.352 6.70 12.45 33.6 114.75 148.35 2.20 2 14 5.75 2.352 6.70 12.45 33.6 114.75 148.35 2.20 2 15 5.75 2.352 6.70 12.45 33.6 114.75 148.35 2.20 3 16 6.81 2.352 6.70 13.51 33.6 114.75 148.35 2.20 2 17 8.47 2.352 6.70 15.17 33.6 61.2 94.8 3.44 89 18 6.94 1.813 11.27 18.22 25.9 114.75 140.65 2.32 6 19 5.84 1.872 15.92 21.76 33.6 114.75 148.35 2.20 15

(28) The examples are numbered from 1 to 19 in order of increasing factor K. It will be noted that there is a correlation between the quality Q obtained for the glass and the factor K, a higher quality glass being obtained in examples 3 to 19. As may be seen it is recommendable for K to be higher than 3.5 and preferably higher than 5.5 and even more preferably higher than 7.5. The energy consumptions of Examples 3 to 19 are also good. Small working ends of 114.75 m.sup.2 are generally enough, except in Example 2 where the blowing intensity is too high. For the blowing intensity used in Example 1, the risk of optical defects appearing on the surface of the glass is low. In contrast, this risk is real in the case of Example 2, since a conditioning basin area of 148.35 m.sup.2 requires a Souff higher than 119% of that of Example 1. It will be noted that if Souff is higher than 90% of that of Example 1, then the risk of optical defects appearing on the surface is too high, which is the case for Example 2. Preferably, Souff is lower than 85% of that of Example 1. In order to achieve this, K should be sufficiently high, in accordance with the present invention, and the ratio of the area under flame to the area of the conditioning basin (S.sub.f/S.sub.cond) should be lower than 4 and preferably lower than 3, and even more preferably lower than 2.5. In the case of Example 10, the area of the conditioning basin is very large and therefore costly to produce, this high area explaining the low blowing intensity. In this configuration, the area of the conditioning basin could be decreased.

(29) In all the examples, the bottom temperature was below 1360 C.

(30) In all the examples except example 7, the glass contained residual bubbles in an amount of less than 50%. Example 7 corresponds to Example 4 except that the depth of the working end was 600 mm. Because of the small depth of the working end, the recirculation loop passing through the conditioning basin also passed through the neck and a good part of the working end but did not reach as far as the inlet of the channel. In the last 7 meters of the working end, the flow of the glass was a plug flow. At the inlet of the channel the glass contained residual bubbles in an amount of 60%.

EXAMPLE 20

(31) The device had the same dimensions as the device of Example 1, except that there was no barrier, and the depth of the working end was decreased by 50% (to 0.72 m) and the width of the working end was decreased to 6 meters. The value of K was 10.22. The recirculation loop passing through the conditioning basin passed through the neck and a portion of the working end but did not extend as far as the channel since there was no recirculation in the last 7 meters of the working end, the flow then being a plug flow. At the channel inlet, the glass contained 50.4% residual bubbles. The other results were as follows: Souff=24%, Sf/Scond=2.41 and Q=8.

Process and device for melting and fining glass

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Y02P40/57

GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

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Abstract

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Description