GLASS FEEDER

Abstract: A glassware feeder contains molten glass and distributes runners of molten glass through a refractory orifice ring (30) having a plurality of discharge holes (32). The refractory orifice ring includes an annular side wall (34) of uniform cross-section, a bottom wall (40) of uniform thickness, and a discrete number of strengthened areas (42) on the interior of the annular side wall at selected locations equidistant from each pair of the holes. The periphery of each of the holes also has an increased thickness (46).

Description: The present invention relates to a glass feeder and more particularly to the refractory orifice ring for such which has a plurality of holes distributing a corresponding number of continuous runners of molten glass to a shear mechanism. Such an orifice ring which may be 27.9 cms (eleven inches) in diameter is subject to a high thermal gradient (on the order of delta T = 926°C (1700°F) which can result in failure of the orifice ring. Failure of the orifice ring can affect the glass in two significant ways. First, a fissure can score the surface of the glass and pass an imperfection on to the finished product. Second, the faulty orifice ring can allow the molten glass to leak from the feeder. These are both serious problems that can be expensive if they remain undetected. Failure also, of course, causes production time to be lost while the orifice ring is replaced and the system returned to normal. Prior art multi-hole orifice rings are shown in U.S. Design Patent Nos. 211,609 and 241,269 and the use of such an orifice ring is illustrated in US-A-4,554,000. During such use, small, hairline stress cracks may develop at the outer periphery which cause the ring to fail when they reach one of the orifice openings. Other prior suggestions are as follows: US-A-4230476 shows a multi-hole orifice ring for use in a glass feeder. The bottom of this orifice ring has a complex contour which incorporates a number of marked changes of slope, and changes in thickness. Such changes result in concentrations of stress and thus tend to lead to cracking of the orifice ring. GB-A-2079266 shows an elongated four hole orifice ring. Such an orifice ring is not designed for use with a conventional feeder which has a circular orifice ring, and has small areas of greatly increased thickness between the several holes. Such areas are again likely to result in concentration of stress in certain areas. GB-A-2140001 shows a four hole orifice ring of the more customary circular shape. This again has a bottom wall which is of varying shape and thickness, likely to result in concentration of stress, leading to cracking. It is an object of the present invention to provide an improved orifice ring which minimizes the likelihood that a stress crack will reach one of the orifice ring holes thereby extending the life of the orifice ring. The invention provides a glass feeder comprising: a spout bowl assembly for containing molten glass including, a spout bowl, and a refractory orifice ring at the bottom of said spout bowl having a plurality of discharge holes defined therein through which runners of molten glass may flow, means for controlling the volume of the runners flowing through said orifice ring discharge holes, wherein the refractory orifice ring comprises an annular side wall of uniform cross-section a planar bottom wall of uniform thickness, a discreet number of ribs defined in said bottom wall and extending between each pair of holes and merging into said annular side wall at selected locations equidistant from each pair of said holes said ribs being ″V″ shaped in cross-section with the legs of the ″V″ directed downwards and cooling tubes being provided between said legs, said bottom wall having an increased thickness around the priphery of each hole. The accompanying drawings illustrate a presently preferred embodiment incorporating the principles of the invention. Referring to the drawings: Figure 1 is an elevational view of a prior art glass spout bowl assembly which delivers molten glass through an orifice plate to a shear meachanism; Figure 2 is a view looking down into the orifice plate of the invention, which is used in place of the orifice plate shown in Figure 1; Figue 3 is a view taken along lines III-III of Figure 2; Figure 4 is a view taken along lines IV-IV of Figure 3; and Figure 5 is an oblique view of the orifice ring shown in Figure 2. Figure 1 shows a prior art spout bowl assembly in which molten glass 10 is contained within a spout bowl container defined by a refractory bowl 12 and a refractory tube 14 which surounds a plurality of plungers 16. The lower ends 18 of the plungers 16 cooperate with an orifice plate 20 to allow runners of molten glass to be delivered to a shear mechanism 22. This shear mechanism shears the runners into discrete gobs which are fed to individual sections of a glassware forming machine (not shown). The orifice ring 30 of the invention has a plurality of holes 32 (here three in-line holes) is designed to define discrete areas 33, as far from the holes 32 as possible, where, in the event of fracture, the fracture will begin. To this end, the side wall 34 (Figure 3) of the orifice plate which extends from the top 36 of the orifice plate to bottom outside edge 38 is of uniform configuration around the orifice plate and the bottom 40 of the orifice plate has a uniform thickness where it joins the side wall, except where a pair of parallel strengthening ribs 42 are located. These strengthening ribs, which have a uniform cross-section, extend perpendicular to the array of holes 32 from one side of the orifice plate to the other, and merge with the sidewall 34 to define localized areas 33 at the periphery of the orifice plate where stress will be concentrated. Grooves 44 are defined in these strengthening ribs to receive cooling tubes (not shown) which maintain constant temperature across each hole so that the molten glass runners will be discharged vertically as desired. Since stress is concentrated at these discrete peripheral areas 33, when the orifice ring fractures, it will start at these areas with the generation of a hairline fracture which will proceed adjacent the strengthening rib 42 toward an orifice hole 32. These discrete areas 33 are located a maximum distance from the orifice holes to increase the distance a hairline fracture must travel to reach an orifice hole. The straight linear array of orifice holes 32 reinforced with a thickened section 46 which is slightly wider than an orifice hole and which extends completely along the linear array of holes 32 (except where the grooves cut across this section). The function of this thickened section 46 is to define with the rib a reinforced area completely around each hole so that any hairline crack that reaches this area will either continue along the rib or be redirected along the margin of this thickened section, and hence, in a direction parallel to the array of holes thereby preventing the crack from reaching a hole.

Claims: 1. A glass feeder comprising: a spout bowl assembly for containing molten glass including, a spout bowl (12), and a refractory orifice ring (30) at the bottom of said spout bowl (12) having a plurality of discharge holes (32) defined therein through which runners of molten glass may flow, means (16) for controlling the volume of the runners flowing through said orifice ring discharge holes (32), wherein the refractory orifice ring (30) comprises an annular side wall (34) of uniform cross-section, a planar bottom wall (40) of uniform thickness, a discreet number of ribs (42) defined in said bottom wall (40) and extending between each pair of holes (32) and merging into said annular side wall (34) at selected locations equidistant from each pair of said holes, said ribs (42) being ″V″ shaped in cross-section with the legs of the ″V″ directed downwards and cooling tubes being provided between said legs, said bottom wall (40) having an increased thickness (46) around the periphery of each hole (32). 2. A glass feeder according to claim 1, characterised in that said refractory orifice ring (30) includes three discharge holes (32) arranged in a straight array. 3. A glass feeder according to claim 2, characterised in that the increased thickness (46) around the holes (32) defines a single elongated raised area having parallel sides.

Inventors: STANKOSKY, MICHAEL J.
Applicants: EMHART GLASS MACHINERY INVESTMENTS INC.
Application year: 1988
Main classification: C03B7
IPC codes: C03B7