Method and apparatus for lubricating molten glass forming molds

Abstract

A burner (16, 116, 216) of a surface-mixing type receives a carbonaceous fuel, for example, an acetylene-based fuel, from a fuel line (20) and an oxidant, such as relatively pure oxygen, from an oxidant line (18), the oxidant being supplied to the burner at a rate insufficient to result in complete combustion of the fuel, to thereby produced a sooty flame that is useful in applying lubricating soot particles to a molten glass contacting surface of a glass manufacturing machine. The burner, which is intermittently operated by a solenoid valve (38) in the oxidant line and by a solenoid valve (40) in the fuel line, has a fuel inlet passage (60) that extends along a longitudinal central axis of a tip element (56) of the burner, and an annular inlet passage (64) that surrounds the fuel inlet passage. The fuel inlet passage, which is otherwise closed at its downstream end, terminates in a multiplicity of separate passages (62) that are arranged in an annular array and through which fuel exits from a burner tip in an annular pattern on an interior of oxidant exiting from the burner in an annular pattern through a passage (66) in an annulus between the tip element and a cap element (58) of the burner. The burner serves to ensure rapid mixing of the fuel and 20 oxidant streams downstream of the burner, to thereby rapidly form an ignitable mixture that can be ignited by a spark igniter (54). Two-way solenoid valves (38, 40) are provided in the oxidant and fuel lines, respectively, to permit the burner to be operated intermittently.

Description

FIELD OF THE INVENTION

This invention relates to a method and an apparatus for lubricating the molten glass contacting surfaces of glass forming molds. More particularly, this invention relates to a method and apparatus of the foregoing character for imparting a layer of carbon soot derived from the partial oxidation of a gas that contains acetylene, such as mapp gas (a mixture of methyl acetylene and propadiene).

BACKGROUND OF THE INVENTION

As is known, for example, from U.S. Pat. No. 5,958,099 (Morettin) or U.S. Pat. No. 5,679,409 (Seeman), it is desirable to lubricate a molten glass contacting surface of a glass manufacturing machine, for example, an internal surface of a forming mold of such a machine, with a thin layer of carbon soot as a substitute for periodically brushing such a surface with a conventional oil and graphite-based mold dopant. Such a soot coating is obtained by the partial oxidation of a carbonaceous gas, such as acetylene or a mixture of an acetylene-based gas, such as methacetylene and propadiene (occasionally referred to as mapp gas or as MAPD gas) by way of a burner whose flame is directed towards the mold surface to be coated.

The aforesaid Seeman '409 patent describes a mold surface soot-coating system in which a mixture of MAPD gas and oxygen, after igniting by a natural gas-derived pilot flame, is directed toward a surface to be coated. As noted in Seaman '409, because of the inherently intermittent nature of the operation of a soot burner in a glass manufacturing machine, a mixture of MAPD gas and oxygen must be carefully controlled so as to prevent backfiring of the flame from the burner into the burner nozzle (column 3, lines 9-20), and it is understood that the system of the Seeman '409 patent has proven to be capable of operating in a successful manner in sooting glass-making molds of a Hartford 28 rotary tableware glass forming machine, where a single sooting burner can service all molds on a rotating table. In that regard, the pulse rate of a sooting burner for a Hartford 28 tableware machine occurs at a fairly high frequency, and any tendency of backfiring to occur by the backflow of oxygen into the fuel line through an air-fuel mixer can be avoided by careful control of the operating condition of the sooting apparatus.

The Hartford 28 glass making machine does not lend itself to the manufacture of hollow glass containers with restricted openings, however, such as the containers used in packaging various food and beverage products, because such products must be manufactured on a machine with split molds. An individual section (I.S.) machine, for example, as described in commonly-assigned U.S. Pat. No. 6,098,427 (Kirkman), or U.S. Pat. No. 3,617,233 (Mumford), the disclosure of each of which of is incorporated herein by reference, is a two-step forming machine type that operates with split glass-forming molds. In view of the need to provide a separate sooting burner for each of the various machine sections of an I.S. machine, a sooting burner for an I.S. machine will operate much less frequently than one for a Hartford 28 machine. For that reason, heretofore, it has not been possible to adapt a premix type burner of the type taught by the Seeman '409 patent to I.S. machine operation because of backfiring occurring as a result of backflow of oxygen from the fuel oxygen mixer into the fuel line during the relatively long durations between burner firing pulses.

The aforesaid '099 Morretin patent does teach a sooting system for the blank molds of a glass making machine that corresponds to an I.S. machine. This reference, which teaches the use of a mixture of acetylene and oxygen, requires two solenoid valves per burner for each fuel line (26, 27), a first solenoid to permit a low rate of fuel flow until ignition has occurred, and a second solenoid to permit a higher rate of fuel flow after ignition has occurred. The need for a second solenoid in this system adds to its cost. More particularly, this system requires a separate set of solenoids for each I.S. machine section, which is not only costly but can also result in section-bysection oxygen fuel variations over the multiple sections of an I.S. machine.

BRIEF DESCRIPTION OF THE INVENTION

According to the present invention there is provided a method and an apparatus for sooting glass-contacting surfaces of a mold of a glass manufacturing machine, such as an I.S. machine. In such method and apparatus, which must operate intermittently with longer dwells between pulses than those of a glass tableware manufacturing machine, for example, a Hartford 28 machine, flame is provided by a nozzle surface mixing burner to which separate streams of fuel and an oxidant, such as relatively pure oxygen, are led, so that no backfiring can occur by a backflow through a mixer of oxidant into a fuel line. In the method and apparatus of the present invention, the fuel, which is preferably mapp gas, is burned in a deficiency of the oxidant to produce soot, and the flame from the burning stream is directed into a glass manufacturing mold along its central axis.

To facilitate the practice of the method and apparatus of the present invention, a nozzle design is provided to ensure rapid mixing of the fuel and oxidant immediately downstream of the nozzle, so that all portions of the mold surface to be coated are contacted by the flame from the nozzle for proper sooting of all such portions. This is accomplished by emitting the oxidant (or the fuel) from the nozzle in an annular cluster of streams that partly outwardly diverge from the longitudinal central axis of the nozzle, and by admitting the fuel (or the oxidant) in an annular stream surrounding the cluster of fuel streams and generally parallel to the longitudinal central axis of the nozzle; consequently, the stream of oxidant readily intersects the fuel streams in the cluster of fuel streams to form a combustible mixture very close to the downstream tip of the nozzle, but without permitting backflow of one of the reactants into the nozzle passage for the other reactant during the dwell periods occurring between cycles of an I.S. machine section.

Accordingly, it is an object of the present invention to provide an improved method and apparatus for applying soot to a molten glass contacting surface. More particularly, it is an object of the present invention to provide a method and an apparatus of the aforesaid character that is suitable for intermittent operation, even with relatively long dwell periods between consecutive pulses, to permit the method and apparatus to be applied to a glass container forming machine, such as an I.S. machine.

It is also an object of the present invention to provide a surface-mixing burner that is well suited for use in the practice of the method and apparatus of the present invention.

For a further understanding of the present invention and the objects thereof, attention is directed to the drawing and the following brief description thereof, to the detailed description of the invention, and to the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of apparatus according to the present invention for use in the practice of a method of the present invention;

FIG. 2 is an enlarged fragmentary view of a portion of the apparatus of FIG. 1;

FIG. 3 is a view similar to FIG. 2 of an alternate embodiment of the apparatus that is shown in FIG. 2;

FIG. 4 is a view illustrating, in cross-section, a burner nozzle for use in the method and apparatus of FIG. 1 to apply soot to a glass container forming machine mold, which is shown in outline;

FIG. 5 is a front elevation view, at an enlarged scale, of the burner nozzle of FIG. 4;

FIG. 6 is a sectional view taken on line 6-6 of FIG. 5;

FIG. 7 is a sectional view taken on line 7-7 of FIG. 5; and

FIG. 8 is an elevation view showing the burner nozzle of FIGS. 5-7 in combination with a spark plug and elements for cleaning soot from the elements ofthe spark plug and the burner nozzle itself.

DETAILED DESCRIPTION OF THE INVENTION

A glass-contacting mold surface sooting system according to the present invention is illustrated generally by reference numeral 10 in FIG. 1. The sooting system 10 has an oxidant supply manifold 12 and a fuel supply manifold 14. A pressurized oxidant from a source (not shown) is delivered to the manifold 12, and a pressurized fuel from a source (not shown) is delivered to the manifold 14. The oxidant delivered to manifold 12 is preferably relatively pure oxygen, such as bottled oxygen from a commercial source, though the use of an oxygen-enriched air supply is also contemplated. The fuel delivered to the manifold 14 is preferably mapp gas. Oxidant from the manifold 12 is delivered to a burner 16 of the surface mixing type through an oxidant line 18, and fuel from the manifold 14 is delivered to the burner 16 through a fuel line 20. Though only one burner 16, one oxidant line 18, and one fuel line 20 are shown in FIG. 1, it is to be understood that there will be a separate set of such elements for each section of an I.S. glass container forming machine, for example eight sets of such elements for an eight-section I.S. machine. The oxidant manifold 12 has a shutoff valve 22 therein; likewise, the fuel manifold 14 has a shutoff 24 valve therein, it being understood that each of the shutoff valves 22, 24, at any given time will either be open or closed, depending on whether or not it is desired to use the burner 16 to apply soot to a molten glass contacting surface of a glass manufacturing machine. Similarly, the oxidant manifold 12 has a pressure regulator 26 therein, at a location downstream of the shutoff valve 22, and the fuel 30 manifold 14 has a pressure regulator valve 28 therein, downstream of the shutoff valve 24, so that oxidant and fuel going into the lines 18 and 20, respectively, will be at regulated pressures. In that regard, the oxidant manifold 12 and the fuel manifold 14 are provided with pressure gauges 30 and 32, respectively, downstream of the pressure regulators 26 and 28, respectively, to ensure that the pressures that are maintained in the oxidant manifold 12 and the fuel manifold 14, respectively, are suitable for proper operation of each burner nozzle 16 that is supplied therefrom.

The oxidant line 18 and the fuel line 20 are provided with shutoff valves 34 and 36, respectively, to permit the burner 16 that is supplied therefrom to be shut off without shutting off any other burners to any other I.S. machine sections to be shutoff. In that regard, it is to be understood that each of the shutoff valves 34 and 36 will either be open or close at any given time, depending on whether or not it is desired to use the burner 16. Flow through the oxidant line 18 to the burner 16, while the shutoff valve 34 is open to flow, will either be on or off, depending on the operation of a two-way solenoid valve 38; likewise, flow through the fuel line 20 to the burner 16, while the shutoff valve 36 is open to flow will either be on or off depending on the operation of a two-way solenoid valve 40. Further, to accommodate changes or variations in the length of the oxidant line 18 and the fuel line 20, the oxidant line 18 is provided with a flexible hose 42 and the fuel line 20 is provided with a flexible hose 44. To prevent backflow through the oxidant line 18 and the fuel line 20, the oxidant line 18 is provided with a check valve 46 and the fuel line 20 is provided with a check valve 48. To suppress any flame that may result from a backfiring of the burner 16, the oxidant line is provided with a flash suppressor 50, and the fuel line 20 is provided with a flash suppressor 52.

The fuel and oxidant flowing from the burner 16, as received from the oxidant line 18 and the fuel line 20, will immediately begin to mix and as they exit from the burner 16, with the fuel stream in an annulus surrounding the oxidant stream in the illustrated arrangement. Shortly thereafter, the at least partly mixed fuel and oxidant, which will at least mix by the turbulence associated with their flow in conjunction with normal molecular diffusion, will form a combustible mixture and the combustible mixture will be ignited by a spark from a spark igniter 54 (shown schematically). By maintaining the flow rate of oxidant through the oxidant line 18 at a level substantially less than that required for complete combustion of the fuel flowing through the fuel line 20, at its flow rate, the flame from the burner 16 will be very sooty and soot therefrom will tend to deposit on any surface that is in the flow path of such flame. While FIGS. 1 and 2 show an arrangement in which the burner 16 operates with fuel flowing therefrom in an annulus surrounding the oxidant, it is also contemplated, as shown in FIG. 3, that a burner 116 can be provided in which oxidant from the oxidant line 18 flows therefrom in an annulus surrounding the flow of fuel from the fuel line 20.

A special surface-mixing burner 216 is shown in FIGS. 5-7. The burner 216, which operates generally according to the arrangement of FIG. 3, that is, with fuel flowing on the interior of an annular oxidant stream, has a tip 56 inserted coaxially into an annular cap 58. Fuel is delivered to the tip 56 along its longitudinal central axis through a passage 60 that is closed at its downstream end, and exits from the tip 56 through an annular array of passages 62, each of which is in fluid flow communication with the passage 60. An oxidant flows in an annular pattern to the tip 56 through an annular passage 66, and flows from the burner 216 parallel to the longitudinal central axis of the tip 56 through an outlet from an annular passage 66 that surrounds outlets from the passages 62 and is defined by an exterior of the tip 56 and an interior of the annular cap 58. With oxidant exiting from the burner 216 parallel to the longitudinal central axis of the tip 56, and fuel flowing from the burner 216 through a multiplicity of small streams, there will be very rapid mixing of the fuel and oxidant streams, and a combustible mixture of fuel and oxidant will form very shortly downstream of the outlet from the burner 216, to be ignitable by a spark igniter such as the spark igniter 54.

As shown in FIG. 4, the sooting nozzle 216 is positioned with its longitudinal central axis coaxial with a longitudinal central axis of a glass manufacturing mold M, which is shown in outline, with only a short distance between an outlet from the burner 216 and an inlet to such mold M. Due to rapid mixing of oxidant and fuel streams from the burner 216, flame from the burner 216 will contact all portions of the inside, molten glass contacting surfaces of the mold M, for effective sooting of all such portions, even those at or very near the inlet to the mold M. Preferably, an annular shroud S, which is shown in outline, is provided to confine flame from the burner 216 so that it flows properly into the mold M. The shroud S begins immediately upstream of the outlet from the burner 216, and extends almost to the inlet of the mold M. FIG. 8 illustrates the assembly of the burner nozzle 216 with a specific embodiment of a spark plug 154. The spark plug 154 has an electrode 70 and a ground electrode 72, which extends from a purge air inlet 74. The spark plug 72 is periodically energized to ignite the streams of fuel and oxidant that flow from the burner nozzle 216 during pulses of the streams, and is spaced from the burner nozzle a distance sufficient to permit the fuel and oxidant streams to mix to a degree sufficient to be combustible. During the soot generation portion of the cycle, the burner nozzle 216 is positioned over a mold, fuel and oxygen are delivered to the burner nozzle 216, and the spark plug 154 is energized to ignite the mixture.

The air purge nozzle 74 receives compressed air from a source (not shown) and discharges air in pulses therefrom through downwardly inclined passages 76, which are directed at the electrode 70 and the ground electrode 72, and through upwardly included passages 78, which are directed at the front ofthe nozzle. Head cleaning to remove soot buildup occurs after the sooting head, burner nozzle 216, has left location above the mold, and cleaning occurs in two phases. In the first phase, a flame from the nozzle 216, and air is introduced through the nozzle 74, which further oxidizes the flame to thereby burn any soot buildup from the nozzle 216 and the electrodes 70, 72. During the second phase, the fuel and oxygen flows to the nozzle are briefly discontinued and the spark plug 154 is not energized, and the purge air is left on for a short period of time to mechanically knock off loose soot.

Although the best mode contemplated by the inventors for carrying out the present invention as of the final date hereof has been shown and described herein, it will be apparent to those skilled in the art that suitable modifications, variations, and equivalents from the mode that has been shown and described, without departing from the scope of the invention, such scope being limited solely by the terms of the following claims and the legal equivalents thereof.

Claims

1. A burner nozzle for partially oxidizing a mixture of a fuel gas and an oxidant gas to produce soot for use in a glass manufacturing process, said burner nozzle comprising: an inner member; and an outer member surrounding at least a downstream portion of said inner member; a first gas passage extending through said inner member for delivery of a first gas through said inner member to at least a single first outlet port from said inner member; a second gas passage extending between said inner member and said outer member in an annulus surrounding said first passage for delivering a second gas to at least one second outlet port through said annulus between said outer member and said inner member.

2-3. (canceled)

4. The burner nozzle set forth in claim 1 wherein said first gas passage includes an annular array of first outlet ports at an end of said first member, wherein said second gas passage includes an annular array of second outlet ports, and wherein said second outlet ports alternate with said first outlet ports in a composite annular array of outlet ports in which said first and second outlet ports alternate with each other.

5. The burner nozzle set forth in claim 4 wherein said second outlet ports comprise slots having long dimensions oriented radially of said composite array.

6. The burner nozzle set forth in claim 5 wherein said first outlet ports are circular.

7. A burner nozzle for depositing carbon soot on a glassware mold, which includes: a burner body having an annular array of individual gas outlet ports, a fuel passage within said body connected to a first plurality of said outlet ports, and an oxidant passage in said body connected to a second plurality of said outlet ports, said first plurality of outlet ports individually alternating with said second plurality of outlet ports around said annular array, such that said array presents alternate fuel and oxidant outlet ports around said annular array.

8. The burner nozzle set forth in claim 7 wherein said second plurality of outlet ports comprise slots having long dimensions oriented radially of said annular array.

9. The burner nozzle set forth in claim 8 wherein said annular array of outlet ports are disposed at an end of said body.

10. The burner nozzle set forth in claim 9 wherein said body includes an inner member and an outer member, wherein said fuel passage is disposed within said inner member, and wherein said oxidant passage is disposed between said inner and outer members.

11. A burner nozzle for depositing soot on a glassware mold, which includes: a burner body having an annular array of individual outlet ports, a fuel passage within said body connected to a first plurality of said outlet ports, and an oxidant passage within said body connected to a second plurality of said outlet ports, said first plurality of outlet ports comprising individual circular outlet ports and said second plurality of outlet ports comprising individual slots that alternate within said array with said circular outlet ports and have long dimensions oriented radially of said annular array.

12. The burner nozzle set forth in claim 11 wherein said annular array of outlet ports are disposed at an end of said body.

13. The burner nozzle set forth in claim 12 wherein said body includes an inner member and an outer member, wherein said fuel passage is disposed within said inner member, and wherein said oxidant passage is disposed between said inner and outer members.