MXPA98006150A - Method and apparatus for supplying a contrachap glass current - Google Patents

Abstract

The invention relates to an apparatus for forming a plywood current having an inner core glass surrounded by an outer shell glass that includes a spout (14) for supplying the core glass from a first source through a first hole (24). A second hole (30) vertically is placed below and aligned with the first hole, and is surrounded by an annular chamber (32) communicating with the second hole through an opening between the first and second orifice. A tube (34) supplies a wrapping glass through the outlet opening (36) of a wrapping glass jet (38) to the annular chamber, such that the glass flows by gravity through the orifices to starting from the first and second source to form the plywood current. A hollow tube (40) inside the wrapping glass spout is positioned with respect to the outlet opening of the spout to measure the flow of wrapping glass through the outlet opening and the supply tube to the surround ring chamber the holes. The interior of the hollow tube is attached to a source (60-72) of gas under pressure to maintain the interior of the tube, and the inside of the thin strip of glass wrapping through the outlet opening of the spout, at a pressure above the ambient pressure surrounding the wrapping glass spout. This high gas pressure inside the wrapping glass strip reverses the differential pressure between the inside and outside of the outlet opening of the jet, so that any tendency of air migrating through the refractory material surrounding the opening is eliminated. of exit and on the wrapping glass strip

Description

METHOD AND APPARATUS FOR SUPPLYING A PLYWOOD GLASS CURRENT The present invention relates to the supply of a glass stream to form glass fillers for the manufacture of glassware, and more particularly to a method and apparatus for supplying a so-called plywood current, in which a core glass or internal is surrounded by a wrapping or outer glass.

Background and Objectives of the Invention Hitherto it has been intended to provide a stream of plywood glass to form glassware having layer wall segments. The U.S. Series Nos. 08 / 374,371 and 08 / 374,372 disclose techniques for supplying such a stream of plywood, in which the core glass from a first source is supplied through a first hole. A second hole vertically separates below and aligns with the first hole, and is surrounded by an annular chamber communicating with the second hole through an opening between the first and second holes. A heated tube supplies the wrapping glass from a second glass source to the annular chamber surrounding the second orifice. The glass flows by gravity through the first and Ref.28081 second hole from the first and second source, such that a stream of plywood emerges from the second hole. This plywood stream can be sheared by conventional techniques to form individual plywood pieces to be supplied to machines for the formation of individual section glassware.

Although the techniques described in the above-mentioned patent, the characteristics of the applications and problems overcome so far in the art, new improvements are still desirable. For example, the presence of air bubbles, sometimes called "blisters," in the envelope glass stream has been a problem. The flow of wrapping glass from the wrapping glass spout is controlled by a spout tube, which is placed over the outlet opening of the wrapping glass spout to measure the flow of wrapping glass at the desired volumetric ratio in the glass. relation to the core glass flow. However, the volumetric flow rate of the wrapping glass is very low, such as in the order of 5 to 10%. Therefore, when using equipment for conventional glassware forming, the extremely low volume of wrapping glass flowing through the outlet of the wrapping glass spout forms a thin strip, about a quarter of an inch thick, around the exit opening and around the upper portion of the heated supply tube, with the volume inside this strip that opens. After a period of operation, bubbles or air bubbles begin to appear in the wrapper glass stream. It is believed that an effect similar to that of a chimney of the heated air inside the interior of the outlet opening of the spout and the interior of the tube for the control of the glass envelope supply creates a differential or pressure gradient between the outside of the atmosphere Environmental of the glass spout of the envelope and the inside inside the thin glass strip. It is believed that this pressure gradient promotes the migration of air through the refractory material of the wrapping glass spout, and eventually into the thin glass strip within the outlet of the spout.

A number of techniques have been proposed in an effort to eliminate this air bubble or blister problem, including coating the spout outlet opening with platinum in an effort to block air migration. The technique that is presently preferred is to periodically "flood" the envelope glass outlet and the heated supply tube with wrapping glass in excess of that necessary to form the plywood stream, and maintain this envelope glass flow. excessive for a period of time. It is believed that this "flood" of the passage of wrapping glass supply eliminates the previously described chimney effect, and further that the hydrostatic pressure in the wrapping glass promotes the flow of wrapping glass in the refractory material of the spout outlet opening to block the air migration passage . When the reduced level envelope glass flow is recovered, the bubbles or air blisters are removed for a period of time. However, the continuous use of the ceramic spout requires that the described "flooding" operation be attempted with an increasing frequency, apparently due to the increased erosion and use of the spout material. It is believed that, as the material of the refractory spout ages, it becomes more difficult to fill the ruptures and air migration steps with the wrapping glass spout. In any event, the described "flood" operation decreases the production of glass, and therefore undesirably increases production costs. In addition, the production of plywood that has bubbles or air blisters in the wrapping layer undesirably results in increased cutting ratios, in addition to increasing production costs.

Therefore, a general objective of the present invention is to provide a method and apparatus for supplying a stream of glass, particularly a stream of plywood, in which the stream is reduced or eliminated. formation of air bubbles or blisters in the thin glass strip of the envelope glass stream, and in which the need to periodically "flood" the supply passage of the glass stream is also eliminated. The aforementioned and other objective of the present invention is to provide a method and apparatus for supplying a glass stream, particularly a plywood stream, which is characterized by improved production efficiency and therefore reduced manufacturing cost compared to similar prior art techniques.

The apparatus for forming a plywood current having an inner core glass surrounded by an outer shell glass according to a presently preferred embodiment of the invention includes a spout for supplying core glass from a first source through a first hole. A second hole vertically separates below and aligns with the first hole, and is surrounded by an annular chamber communicating with the second hole through an opening between the first and second holes. A tube supplies wrapping glass to the annular chamber from the outlet opening of a wrapping glass jet, such that the glass continuously flows by gravity through the holes from the first and second sources to form the stream. of plywood. A dispensing tube The recess inside the wrapping glass spout is positioned with respect to the outlet opening of the spout for measuring the flow of wrapping glass through the outlet opening and the supply tube to the annular chamber surrounding the openings. The inside of this spout tube is attached to a gas source under pressure to maintain the inside of the tube and the inside of the thin strip of the wrapping glass through the spout outlet opening at a pressure above the ambient pressure that surrounds the wrapping glass spout. This high gas pressure inside the wrapping glass strip reverses the differential pressure between the inside and outside of the outlet opening of the jet, so that any tendency of air migrating through the refractory material surrounding the opening is eliminated. of exit and on the wrapping glass strip.

In accordance with another aspect of the present invention, there is provided an apparatus for supplying a glass stream that includes a glass jet having a lower outlet opening and a described flow control jet tube within the jet. The spout tube has a closed upper end, a hollow interior and an open lower end adjacent to the outlet opening of the spout, and the position of the tube within the spout is controlled to control the flow of glass through the outlet opening. The hollow interior The flow control tube is attached to a source of gas under pressure to maintain the interior of the tube at a pressure above the ambient air pressure surrounding the spout. Therefore, a third aspect of the invention contemplates a method of preventing the infiltration of air through the refractory material around the outlet opening of the spout in the glass flowing through the outlet opening by supplying gas under pressure to the flow control tube to maintain the gas pressure inside the tube and within the outlet outlet of the spout above the ambient air pressure around the spout. By way of example, the gas pressure within the flow control tube and the outlet outlet of the spout can be maintained at a pressure of approximately 5.08 cm of water column above the ambient. The gas contained under pressure within the spout can comprise air, nitrogen or argon. In some applications, such as the manufacture of amber glass, it may be desirable to provide a reducing gas within the spout and in contact with the gas flow, which will therefore advantageously change the nature of the atmosphere in contact with the flow of glass. For example, methane or other fuel gas can be injected into the spout to burn and maintain a high pressure reducing atmosphere in contact with the glass stream.

Brief description of the drawings.

The invention, together with the additional objects, features and advantages thereof, will be better understood from the following description, the amended claims and accompanying drawings in which: Fig. 1 is a fragmentary plan schematic diagram of a glass supply system according to a presently preferred embodiment of the invention; Fig. 2 is a fragmented sectional view with an enlarged scale of a portion of the delivery system illustrated in Fig. 1; Fig. 3 is a fragmented sectional view with an enlarged scale of another portion of the glass supply system illustrated in Fig. 1; Y Fig. 4 is a sectional view similar to that of Fig. 3 but showing a modified embodiment of the invention.

Detailed description of the preferred embodiments.

The drawings illustrate a system 10 for supplying a stream of plywood. A first antecryol 12 supplies core glass to a cylinder or spout 14 having an opening 16 at the lower end thereof. The spout 14 is surrounded by a protective envelope 18, preferably constructed of non-magnetic material, such as stainless steel. The spout tube 20 and a piston 22 control the supply of core glass from the spout 14 through the opening 16 through and through one or more first holes 24 carried by an upper orifice ring 26 below the spout 14. lower orifice ring 28 carries one or more second holes 30 positioned below the holes 24 and axially aligned therewith. The orifice (s) 30 is surrounded by an annular chamber 32 formed between the orifice rings 26, 28. The chamber 32 communicates with the orifice (s) 30 by means of a space or side opening between the holes 24, 30. annular chamber 32 is attached by a supply tube 34 to the opening 36 at the lower end of a wrapping glass dispenser 38. The dispenser 38 includes a supply control dispensing tube 40, and is attached to a glass forehearth envelope. The supply pipe 32 is heated in resistance by control electronics 41 to maintain the flow of glass of wrapping, to the chamber 32. To describe the scope so far, the system 10 is essentially the same as described in the U.S. applications. mentioned above Series Nos. 08 / 374,371 and 08 / 374,372. The background of such a request is directed in particular to the construction of the wrapping glass supply tube 34, while the last of such requests is directed in particular to the construction of orifice rings 24, 26. The descriptions of such requests, both of which are assigned to the attorneys-in-fact thereof are incorporated herein by reference for antecedent purposes.

A feature of the supply systems is that the volumetric ratio of the wrapping glass to the core glass is extremely low, which indicates that the amount of wrapping glass required per unit volume of core glass is extremely low. Therefore, the envelope glass flow rate is extremely low, and does not fill the volume of either the supply tube 34 or outlet outlet of the dispenser 36. As shown in greater detail in FIG. 2, the low volumetric flow rate of wrapping glass is such that the glass which continuously flows under the lower open end of the spout tube 40 through the outlet opening of the spout 36 and at the upper end of the supply pipe 34 forms a thin wall or strip around the conical interior of the opening 36 in the inside the tube 34. In current systems for the commercial production of wrapping glass, this thin layer or glass wrapping strip 42 around the conical interior of the outlet opening 36 is about a quarter of an inch thick. This thin strip continues in the tube 34, which is positioned at an angle to the opening axis 36. The glass that initially tends to flow along the upper surface of the tube 34 eventually breaks off from the surface of the tube, forming a strip 44 which melts in a thin flow 46 which flows along the angled lower surface of the tube 34. The flows 42, 44, 46 are continuous, without lumps and laminar, and do not cross themselves, which will tend to catch the air bubbles. It is therefore believed that a "chimney effect" caused by the heated air inside the tube 40, the glass strip 42 and the glass strips 44, 46, creates a pressure gradient or differential with respect to the external atmosphere, which promotes the migration of air through the refractory material of the jet 38 that surrounds the outlet opening 36. This air migration eventually reaches the interior of the refractory material, and results in bubbles or blisters within the strip 42.

To overcome this effect, the present invention contemplates that a source of gas under pressure is attached to the open interior of the spout tube 40, outlet opening 36 and tube 34.

Especially, a lid 50 is placed on the upper end of the tube 40. A hollow tube 52 extends upwardly from the lid 40, and is surrounded at its upper end by a tube 54 of larger diameter. Therefore, the tubes 52, 54 effectively form a rotary union 56 that allows both the rotation of the tube 40 and the vertical movement of the tube 40 by means of the bracket 58 to control the opening that measures the flow between the open lower end of the tube. tube 40 and the upper end of the outlet opening 36. The rotating union 36 is connected via a conduit 59 to a fan 60, which continuously supplies gas under pressure (ambient air in this mode) through the conduit 58 and the union 56 to the hollow interior of the tube 40. A pressure gauge 62 is attached to the joint 56 to monitor the air pressure inside the tube 40. An air baffle 64 is externally placed around the tube 52 below the joint 56 to prevent direct impact on the lid 50, which will unduly cool the glass inside the spout 38.

The presence of low gas pressure inside the tube 40 and the outlet opening 36 divides the strip 44 (FIG 2) and fills the upper interior of the tube 34 with air. However, because the tube 34 is made of metal composition, preferably platinum, the migration of air through the ceramic insulating material surrounding the tube 34 is not a problem. Rather, it is the elevated air pressure inside. of the exit opening 36 that it effectively cancels the formerly existing "chimney effect" and reverses the differential or pressure gradient through the ceramic material surrounding the outlet of the spout. The creation of air bubbles or blisters within the wrapping glass material is substantially eliminated. It has been found that the pressure within the tube 40 and the outlet opening 36 in the range of about 0.1270 to 25.40 centimeters of water column above the ambient air pressure, and more preferably about 5.08 centimeters of water column above. of the ambient air pressure produces satisfactory results.

As mentioned above, FIGS. 1-3 illustrate a presently preferred embodiment in which the gas injected is air. However, other gases can be used to obtain other desirable effects. FIG. 4 illustrates a system in which the rotating union 56a includes a tube 70 for connecting an external gas source 72 to the interior of the tube 56. For example, the gas from the source .72 may comprise nitrogen or argon. In the manufacture of amber glass, for example, it will be desirable to maintain a low oxygen or reduction atmosphere within the spout 40 in contact with the glass strip to prevent oxidation of the glass. For this purpose the gas source 72 may comprise a source of methane or other combustible gas. The combustion of such gas within the volume The upper tube 40 will produce the desired reduction atmosphere while maintaining high pressure to prevent gas migration through the spout material.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the foregoing, the property contained in the following is claimed as property.

Claims (16)

1. In an apparatus for forming a plywood current having an inner core glass surrounded by an outer wrapping glass, the apparatus includes means for supplying core glass from a first source through a first hole, which means a second hole vertically separated below and aligned wthe first hole wa chamber surrounding the second hole and communicating wthe second hole through an opening between the first and second hole, and means for supplying wrapping glass from a second source to the chamber, such that the glass flows by gravity through the holes from the sources through the holes to form the plywood current, means for supplying wrapping glass including a spout having an outlet opening and a spout tube positioned wn the spout to control the supply of wrapping glass through the spout opening, characterized in that the improvement of the apparatus further comprises: means for supplying gas under pressure to an internal volume to the tube to maintain the internal volume of the tube at a pressure above the ambient pressure surrounding the spout.

2. The apparatus according to claim 1, characterized in that the means for supplying wrapping or covering glass further comprises a heated supply tube which extends from the outlet opening of the dispenser to the chamber, the dispensing tube is placed wwrespect to the opening so that the glass exiting the opening and entering the heated tube forms a thin flow of glass extending along the inner wall of the outlet opening and the heated tube.

3. The apparatus according to claim 2, characterized in that the spout tube has a closed upper end and an open lower end positioned above the outlet opening, and wherein the means for supplying gas under pressure comprises a rotating union attached to the upper end. closed of the tube.

. The apparatus according to any preceding claim, characterized in that the means for supplying gas they comprise means for supplying air at high pressure to the tube.

5. The apparatus according to claim 1 or 2, characterized in that the means for supplying gas comprise a rotary union attached to an upper end of the tube and means for connecting such connection to a gas source under pressure.

6. The apparatus according to claim 9, characterized in that the gas comprises a combustible gas that burns inside the apparatus to maintain a high pressure reducing atmosphere wn the tube.

7. The apparatus according to any preceding claim, characterized in that the gas wn the tube is at a pressure in the range of about 0.1270 to 25.40 centimeters of water column.

8. The apparatus according to claim 7, characterized in that the pressure is approximately 5.08 centimeters of water column.

9. The apparatus for supplying a stream of glass, characterized in that it comprises: a glass spout having a lower outlet opening, a flow control spout located inside the spout, the tube has a closed top end, a hollow interior and an open bottom end positioned adjacent to the spout outlet opening, means for controlling the position of the lower end of the tube wrespect to the outlet opening for controlling the flow of glass through the outlet opening, and means for supplying gas under pressure into the hollow of the tube to maintain the interior of the tube at a pressure above the ambient air pressure surrounding the spout.

10. The apparatus according to claim 9, characterized in that the outlet opening is conical, and wherein the tube is positioned wrespect to the outlet opening so that the glass exiting the opening forms a film of Glass that extends around the conical opening, the inside of the film is pressurized from the tube.

11. The apparatus according to claim 10, characterized in that the means supplying gas comprise a rotary union attached to the closed upper end of the tube.

12. In an apparatus for forming a stream of plywood, in which the core glass and the wrapping glass are supplied from the separate sources at a volumetric ratio, in which the wrapping glass is much smaller than the glass of core, and in which the wrapping glass is dosed from a jet of refractory material through an opening of the jet through a hollow jet tube, such that the wrapping glass flows as a thin layer around the periphery of the tube. the opening, a method of preventing infiltration of air through the refractory material of the spout opening to maintain a gas pressure inside the tube and within the opening above the ambient air pressure around the spout.

13. The method according to claim 12, characterized in that the pressure inside the tube and the opening is maintained at a pressure in the range of about 0.1270 to 25.40 centimeters of water column above the ambient.

14. The method according to claim 13, characterized in that the pressure is about 5.08 centimeters of water column.

15. The method according to claim 12, characterized in that the gas is selected from the group consisting of air, nitrogen, argon and combustible gases.

16. The method according to claim 12, characterized in that the gas comprises a combustible gas, and wherein the method comprises the additional step of burning the gas to maintain a low oxygen atmosphere at high pressure within the tube and within the opening. SUMMARY OF THE INVENTION The invention relates to an apparatus for forming a plywood current having an inner core glass surrounded by an outer shell glass that includes a spout (14) for supplying the core glass from a first source through a first hole (24). A second hole (30) vertically is placed below and aligned with the first hole, and is surrounded by an annular chamber (32) communicating with the second hole through an opening between the first and second orifice. A tube (34) supplies a wrapping glass through the outlet opening (36) of a wrapping glass jet (38) to the annular chamber, such that the glass flows by gravity through the orifices to starting from the first and second source to form the plywood current. A hollow tube (40) inside the wrapping glass spout is positioned with respect to the outlet opening of the spout to measure the flow of wrapping glass through the outlet opening and the supply tube to the surround ring chamber the holes. The interior of the hollow tube is attached to a source (60 or 72) of gas under pressure to maintain the interior of the tube, and the inside of the thin strip of glass wrapping through the outlet opening of the spout, at a pressure above the ambient pressure surrounding the glass spout of envelope. This high gas pressure inside the wrapping glass strip reverses the differential pressure between the inside and outside of the outlet opening of the jet, so that any tendency of air migrating through the refractory material surrounding the opening is eliminated. of exit and on the wrapping glass strip.