US1217340A - Manufacture of plate-glass. - Google Patents

Description

R. s. PEASE.

MANUFACTURE 0F PLATE GLASS.

APPLlcATioN FILED luNE 5,1915.

` Patented Feb.`27, 1917.

6 SHEETS-SHEET l.

- ATTORNEYS v i R. S. PEASE.

MANUFACTURE o F PLATE GLASS.

` APPLICATlON FILED JUNE 5,1915. 1,217,340. Patented Feb.27,`1917.

6 SHEETS-SHEET 2.

\ lNVENTOR H @www f MM WITNESSES H. S. PEASE.

MANUFACTURE 0F PLATE GLASS.

APPLICATION FILED IuNE 5.19I5.

1,217,340. Patented, Feb'. 27, I9I7.

6 SHEETS-SHEET 5.

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wITNEssI-:s INvENoH ATTORNEYS R. s. PEASE,

NIANUFACTURE 0F PLATE GLASS.

APPLICATION FILED .LUNE 5. I9I5.

Patented Feb, 27, 1917.-

s SHEETSAHEU a.

vUNITED sTATEs PATENT oEEroE. f

ROGER S. PEASE, OF PITTSBURGH, PENNSYLVANIA, ASSYIGNOR TOPITTSBURGH PLATE GLASS COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN-` SYLVANIA.

Specification of Letters Patent.

Patenteareb. 27, 1917.

Application led J une 5, 1915. ySerial No. 32,365.

To all whom it may concern:

Be it known that I, ROGER S. PEASE, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in the Manufacture of Plate-Glass, of which the following is a specification.

The invention relates to the manufacture of plate glass and has for its primary objects; the provision of a process wherein the length of time necessary to get the glass into comlition for pouring is reduced; the provision of a process wherein the fuel consumption as compared with thatof the present procedure is reduced; and the provision of a process wherein the life of the pots employed is increased and the quality of the glass improved. Certain embodiments of the invention are illustrated in the accompanying drawings, wherein Figure 1 is a longitudinal section through the forward half of the furnace employed in carrying out the operation, Fig.'2 is a section on the line II--II of Fig. 1, Fig. 2A is a rear elevation of the pot tipping apparatus shown in Fig. 1, Fig. 3 is a longitudinal section through the rear half of the furnace of iig. 1, Fig. 4 is a section on the line IV-V of Fig. 3, Fig. 4^ is a section through the dog-house and lifting block taken at right angles to the section of Fig. 3, Fig. 5 is a horizontal section of the forward half of the furnace as illustrated in Fig. l, such section being taken just above the surface of the glass, Fig. 6 is a horizontal section of the rear half of the furnace as illustrated in Fig. 3, such section being also taken above the surface of the glass, Fig. 7 is a longitudinal vertical section through the forward end of the furnace in which a different method of procedure in filling the pot is practised, Fig. 8 is a plan view of one of the doghouses showing the transfer and pot cleaning rollers, and Fig. 9 is a side elevation of Fig. 8 with the pot tongs shown suspended from a traveling crane.

In the practice of my invention I preferably employ a long relatively narrow tank such as that illustrated in Figs. 1, 3, 5 and 6, but it will be understood that the form o f the tank may be varied to suit requirements. The forward end of the furnace as illustrated in Figs. 1 and 5 .comprises a pair of y introducing channels or canals 1 and 2 having the cross section indicated in Fig. 2, and the mam meltmg tank portlon 3, such tank being heated preferably by regenerator gas furnaces of the Siemens type and having an arch or crown Ll (Fig. 2) extending from one longitudinal side wall ofthe furnace to the other. trated in Figs. 3 and 6 is very similar to the forward half and comprises the tank portion 3 forming a continuation of the portion 3 of Figs. 1 and 5, and two end channels or canals 5 .and (S, such channels-or canals being shown in cross-section in Fig. 4. i

Heat is supplied to the melting tank 3 from the regenerators to the passages or ports 7 in the, usual way, vand the heat regulation is such that the ktemperature at the left hand end of the ltank is higher than at the right hand end, the maximum temperature at the left hand end of the tank being sufficient to properly refine the glass and ap- The rear half of 'the tank as illusproximating 2700o F. The temperature in the channels or canals 1 and 2 into which the pots are introduced is much less than in the melting portion ofthe tank, as is also the temperature in the channels or canals 5 and 0 at the other end of the furnacewhere the pots are removed and at which point itis desirable to havev al temperature approxirrating a proper pouring-temperature of the ass. i The glass batch with which the melting tank 3 is supplied is introduced into a receptacle 8 in the top of the furnace and passes down and forms the cone 9 illustrated in Fig. 2. Gas burners are provided to play upon this body of unmelted material, and the temperature at this point is relatively high. The batch is supplied to the cone 9 at a rate sufficient to take-the place of the material which is melted, and the Width of the tank at this point is sufficient to permit the pots employed to pass the cone 9 on either side thereof as indicated in Fig. 5. However, the method of supplying batch to the tank constitutes no part of my present invention and any suitable means may be employed for performing this function.

The pots employed are preferably of the relatively shallow dish shape illustrated in Figs. 1 and 5, the pots being somewhat oblong, but it will be understood that any other form of pot meeting the requirements may be employed. The pots are preferably made of a `capacity approximating that of the plate glass melting pot now in use and are made of the same composition of clay. These pots, to which the reference numeral 10 is applied, are preferably provided at their upper edges with the rims or beads 11, beneath which the carrying tongs engage when the pot is removed from the tank.

When the pots reach the right hand end of the channels 1 and Q they are filled with glass by means of the tilting device illustrated in Figs. 1, 2^ and 5. rlhis tilting device operates through an oj'iening 12 in the roof ot' the tank, such opening being closed by means ot' a cover 13 when the tilting device is not in use. The tilting device consists of a weighted bar 1-'1 raised and lowered by means of a connection 15, and a semi-circular member 16 adapted to fit the. edge of the pot and pivoted to the lower end of the member 14. A guide arm 17 pivoted to the member 16 and having a pivot and slot connection with the bar 14 serves to hold the member 16 in a horizontal position when the apparatus is raised. The bar 14 lies to the right of the center of gravity of the pot, so that when the member 1G is placed in position upon the pot and the connection 15 lowered. the Weight causes the pot to tilt to the position indicated in Fig. 1, thus allowing the molten glass to run into the pot, after which the tilting device is lifted and the neXt pot brought into position. After the pots have passed through the melting furnace v3 and through the canals or channels 5 and 6 at the right hand end of the melting tank, they are removed or lifted from the glass to a position at which they may be engaged by the carrying tongs by means of the lifting blocks 18 illustrated in Figs. 3, 4^ and (3. These liftinfr blocks 18 are provided with guides 19 wor'lting in recesses in the walls of the tank (Fig. G), and have their lower sides recessed as indicated at 2O (Fig. 8). Connections are provided for supplying air under pressure to this recess, so that after a pot has been floated over the lifting block, theair supplied to the recess 20 through the duct 20 (Figs. 3 and 4) causes the block to l'ift the pot to the position illustrated in Fig. 3 at which time the cover 21 may be removed and the carrying tongs applied to the pot to transport it for pouring.

Referring to Figs. 8 and 9, the pot removing and handling apparatus consists of a series of rollers 26 provided with concave bearing surfaces 27 of the same contour as the bottom of the pot, over which the pots may be dragged by means of a carrying tong 28 suspended from a traveling crane Q9 by means of a cable 30. The dragging vof the pot over the rollers serves to remove all strings of glass and foreign matter which might adhere to the pot, and the number of the rollers is sufficient that the adhering glass will be chilled before reaching the extreme I end rollers. Vhen the pot reaches the end nals or channels 1. and 2, the pots 10 are intrm'luced empty as indicated in Fig. 1, such pots either being new pots or pots from which a pour has just been made. The pots at this timeI are of course relatively cold and lit is desirable that they should be heated before being filled with glass in order to avoid strain tending to injure them. The pots are floated to the right through the channels 1 and'2, and by the time they arrive at the right hand end of such channels are in condition to receive the molten glass, at which time they are tilted by the device indicated in Fig. 1,y thus filling them with molten batch, which by reason of its proximity to the point of introduction of the batch at Q is relatively crude and unrefined- The pot is then moved gradually to the right through the melting tank 3, the length of this melting tank being such, and the time consumed in the passage of the pots being such that by the .time the pots are floated therethrough the glass Will be entirely refined and ready for use. During this period. any bubbles caused in the glass incident to the dipping of the glass into the pot and any bubbles due to the chemical reaction in the pot during the refining operation will have disappeared and the quality of the glass will correspond to, or be superior to that, of the glass as reduced from dry batch in individual pots as in the method now universally practised. This refining operation Will ordinarily require several hours, the pots being moved to the right at a rate necessary to secure the desired results, either manually, or by the current of the glass which sets to the right due to the removal from the furnace of the pots at the right end thereof. The movement of the pots to the right may be retarded for any desired interval by means lof the projections 23, 24 and 25 illustrated in Figs. 1 and 5, such projections extending above the surface of the glass and serving to stop the movement of the pots when they are turned with their longitudinal axes transverse to the longitudinal axis of the furnace as shown in Fig. 5. It will be understood that openings are provided through the walls of the tank to give access, by mea-ns of moving rods, to the pots at various points throughout the length of the furnace so that the movements of the pots may be kept under control.

As the temperature at which the glass is poured is necessarily lower than the temperature at which the glass is refined, the temperature in the right hand end of the melting tank isv reduced, so that when the pots reach such right hand end of the furnace, the temperature of the glass is reduced to a very considerable extent. The pots as they arrive at the extreme right hand end of the channels or canals and 6 are elevated by the lifting blocks 18 and carried away by means of the carrying tongs secured to an overhead conveyer in the manner previously described. The operation of pouring thc glass is ust the same as heretofore practised, and after the glass is poured the pot is returned to the canals 1 and 2 at the left hand end of the furnace as heretofore described.

The foregoing operation presents many advantages over the method now universally practised, and comprising the reduction of the glass from dry batch in individual pots in a furnace. vIn this old operation a large amount of time is consumed in bringing the pots to a proper temperature and in melting the batch in the pots preliminary to the refining action. The removal of the pots from the furnace requires the removal of the side wall thereof and the heat losses involved are very great. Furthermore, the strains imposed upon the pot due to the method of applying the heat thereto are so great that the pots can be used only a. limited number of times which fact renders the expense for pots very heavy. My method of procedure minimizes these difficulties. The loss incident to heating a pot and reducing the batch to a molten state is avoided, since the number of pots is so large that the operation is a substantially continuous one, and the batch is already melted when it is dipped into the pot. The heat losses incident to the insertion of the pot and the removal thereof is relatively small since the openings required for this purpose are not large and the portions of the tank to which they communicate have av relatively low temperature. The pots are not subject to any undue strain and will last indefinitely, the heating and cool ing operations b`eing gradual, and the surface of the pot being substantially surrounded by molten glass so that it is not subject to uneven heat conditions, and is little exposed to the action of the heated gases in the tank, as is the case in the old process wherein substantially the entire outer surface of the pot is exposed to the action of the air in the furnace. The glass in the melting tank is continuously changed by the addition of batch and the withdrawal of the molten glass, so that the body of glass tends to remain in relatively good condition, but if a more rapid change of the body of glass is desired, a portion thereof can be Withdrawn for the manufacture of Window glass or any' other desired purpose. The relatively shallow type .of pot employed is advantageous, since. a relatively large area of glass will be exposed to the radiated heat from the crown or arch of the furnace, thus increasing the rapidity of the refining operation. It Will also be seen that the labor incident to the filling of the pots is reduced to a minimum, and is very much less than in the old type, which involved the fill-ing of the pots after they were placed in the furnace by means of ladles inserted through openings in the walls of the furnace. to the method of procedure will be readily apparent to those skilled i'n the art.

In Fig. 7 a modified procedure for securing the filling of the pots is illustrated. In this construction illustrated in Fig. 7 canals or channels l', heated by burners 26, as in the other construction, are provided, and the melting tank 3 is also the same in this construction. Instead of the tilting device illustrated in Fig. l, however, the filling device 27 is employed, such filling device comprising a hopper containing batch and a spout or tube 28 extending down through the roof of the tank. When the pots l0 arrive beneath this spout they are filled with the requisite amount ,of dry batch instead ofv melted batch being dipped upv as heretofore described and illustrated. lThe procedure from this point on is -iust the same as in the operation heretofore described, the refining operation being however necessarily somewhat longer due to the fact that thev batch in the pot must be melted before it is refined. The pots are made also somewhat larger when this method is employed, since the dry batch occupies more space than when melted down.

This method of procedure, while having the disadvantage of requiring somewhat longer time than the procedure heretofore described, has the advantage that the character of the mixture introduced into the pot is more definitely and accurately fixed than is the case where the. mixture is dipped up from the body of molten glass. and furthern'un'e, the danger of the bubbles induced by the dipping operation is avoided. The character of the batch introduced to the pots by this method is substantially the same as that introduced into the pots during the practice of the method as now commonly used and as described heretofore. When this method of Fig. 7 is practised it would be highly desirable to utilize the body of glass in the melting tank for the manufacture of window glass or for some other simi-.

lar purpose so that the body of glass would not be wasted and couldl he kept in good condition by changing. While the process of both modifications is designed primarily for the production of plate glass, the glass in the pots might be used for other purposes Other advantages incident and the broad invention is not limited to the step of pouring the glass from the pots after they are removed from the furnace.

What I claim is:

1. The process of making plate glass which consists in fioating a pot containing glass along the surface of' a body of molten glass, exposing the pot and its contents to a refining heat during its passage through the body of' glass, and then removing the pot with its contents from the body of glass and pouring the glass from the pot.

2. The process of making plate glass v which consists in Hoating a pot containing glass along the surface of a body of molten glass, exposing the pot and its contents to a refining heat and then to a decreasing heat during its passage through the body of glass, and then removing the pot with its contents from the body of glass and pouring the glass from'the pot.

3. The process of making plate glass which consists in fioating a pot upon the surface of a body of molten glass, dipping up into the pot from the body of molten glass a quantity of the glass, floating the pot along the surface of the body of molten glass and exposing it and its contents to heat during such movement, and then removing the pot with its contents from the body of glass and pouring the glass from the pot.

4. The process of making plate glass which consists in floating a pot upon the surface of a. body of molten glass, dipping into the pot from the body of molten glass a quantity of unrened glass, Hoating the pot along the surface of the body of molten glass and exposing it and its contents to a relining heat to refine the glass and then to decreasing heat, and then removing the pot with its contents from the body of glass and pouring the glass from the pot.

5. The process of making plate glass which consists in floating a pot in a body of molten glass until the pot attains a desired temperature, dipping nip into the pot a quantity of unrcfined glass, ,outing the pot along the body of glass and exposing it and its contents to n refining heat to retiietlie glass and then to a decreasing heat, and then removing the pot with its contents from the body of glass and pouring the glass from the pot.

G. The process of making plate glass which consists in ioating a pot containing a quantity of glass, through a glass melting tank uponl the surface of the molten glass contained therein, and then removing the pot from the tank and pouring the glass contained therein.

7. The process of making glass which consists in floating a pot upon the surface of a body of molten unrefined glass, dipping up into the pot from the body of molten glass a quantity of the glass, floating the pot along the surface of the body of glass and exposing it and its contents to a refining heat and then to a lesser degree of heat to permit of' the cooling of the glass in the pot, and then removing the pot with its contents from the body of glass.

8. rlhe process of making glass which consists in fioating a pot containing glass along the surface of' a body of molten glass, eX- posing the pot and its contents to a refining heat during its passage through the body of glass and then removing the pot With its contents from the body of glass.

9. The process of making glass which consists in floating a pot upon the surface of a body of molten glass until the pot attains a desired temperature, supplying the pot with glass, floating the pot along the body of glass and exposing it to a refining heat, and then to a decreasing heat, and finally removing the pot with its contents from the body of molten glass.

ROGER S. PEASE.

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