Apparatus and method for obtaining uniform gobs in a triple gob feeder

An apparatus and method for use in a triple gob feeder of a glass forming apparatus for forming molten glass gobs of uniform size, weight, volume and shape by equalizing the temperatures of the molten glass flowing through orifices in a triple gob orifice ring. Molten glass is retained in a middle reservoir of the triple gob orifice ring for a relatively longer average period of time than in end reservoirs of the ring preferably by providing a middle reservoir having a relatively larger volumetric size than the end reservoirs. In addition, the middle reservoir is cooled by directing a coolant through channels in a bottom surface portion of the orifice ring and onto external surfaces surrounding the middle reservoir.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to an apparatus and method for obtaining uniform gobs 
in a triple gob feeder of a molten glass forming apparatus, and more 
particularly for obtaining uniform gobs by providing uniform molten glass 
temperatures in a triple gob orifice ring. 
In a common commercial process for the production of glass containers, such 
as bottles, jars and the like, and other types of glassware, glass 
components are initially heated to an elevated temperature level, such as 
2000.degree. to 2100.degree. F., in a forehearth to form a relatively 
uniform mass of molten glass. The molten glass is fed to a spout bowl 
having a glass discharge hole in a central portion of the bottom wall of 
the bowl. A tube is provided in the spout bowl having a diameter slightly 
larger than the discharge hole and adapted to engage the bottom wall of 
the spout bowl surrounding the glass discharge hole. The tube is raised 
and lowered to regulate the flow of molten glass in the spout bowl through 
the discharge hole. The molten glass is then received by and temporarily 
stored in an orifice ring positioned immediately below the discharge hole 
of the spout bowl. Molten glass in the orifice ring is urged through 
orifices in the orifice ring at regular intervals by reciprocating 
plungers mounted above the orifice ring in axial alignment with the 
orifices. As the molten glass flows through the orifices, it is formed 
into a continuous rod-like body of glass which is cut by shears mounted 
below the orifice ring into discrete units of desired size, referred to as 
"gobs". Commonly used orifice rings have one, two or three orifices 
(referred to as "single gob", "double gob" or "triple gob" orifice rings, 
respectively) to simultaneously produce one, two or three gobs. Prior 
examples of triple gob orifice rings are disclosed in U.S. Pat. No. 
3,516,812 and U.S. Design Pat. No. De. 241,269. The gobs produced by the 
foregoing process are then fed to additional glass forming apparatus to be 
formed into the desired article. 
In the commercial application of the foregoing process, uniformity of the 
size and shape of gobs produced is critical not only to ensure production 
of a uniform, quality article, but also to minimize use of excess glass 
while ensuring sufficient glass in the gob to produce a minimum wall 
thickness in a container, such as a bottle. The size and shape of gobs 
produced is highly dependent on the viscosity of the molten glass in the 
orifice ring and therefore upon the temperature of the glass flowing 
through the ring orifices. It has been found that it is particularly 
difficult to maintain uniform temperatures of glass flowing through the 
orifices of a conventional triple gob orifice ring having three orifices 
oriented in the ring with orifice centers in substantially linear 
alignment forming two end orifices located adjacent the sides of the 
orifice ring and a middle orifice located in a central portion of the 
orifice ring. With such an arrangement, molten glass adjacent the end 
orifices is cooled relatively more than molten glass adjacent the middle 
orifice due to the proximity of the end orifices to the sides of the 
orifice ring. Presently used designs additionally pack more insulation 
around a middle reservoir supplying molten glass to the middle orifice 
than end reservoirs supplying molten glass to the end orifices, thereby 
compounding the problem. With a relatively higher temperature of molten 
glass adjacent the middle orifice, the glass flowing through that orifice 
tends to have a relatively lower viscosity resulting in the production of 
gobs from the middle orifice of relatively higher glass content and 
elongated shape. Some prior art triple gob orifice rings further increase 
the problems of uniform gob production by utilizing orifices of uneven 
wall height. 
It has now been found that the foregoing problems can be overcome and gobs 
of uniform size, weight, volume and shape can be produced in a triple gob 
feeder, by equalizing the temperatures of the molten glass flowing through 
a triple gob orifice ring by retaining molten glass in a middle molten 
glass reservoir of the orifice ring for a relatively longer average period 
of time than in end reservoirs of the ring, and, preferably, by 
additionally cooling the middle reservoir of the ring. The uniformity of 
gobs produced may be further improved by providing orifices in the ring 
having a uniform height.

DESCRIPTION OF PREFERRED AND ILLUSTRATIVE EMBODIMENTS 
As hereinafter described, the orifice ring and orifice ring holder means 
are generally referred to in the vertical, upright position as normally 
located in use. Thus, such terms as "upper", "top", "lower" and "bottom" 
refer to the vertical upright position. In addition, such terms as "axial" 
and "axially extending" refer to the central vertical axis of the orifice 
ring when located in the vertical, upright position. Such terms as 
"radial" and "radial extending" relate to the central vertical axis. The 
method and apparatus of the invention is adapted to be used in association 
with conventional gob feeder systems, such as, for example, a Hartford Gob 
Feeder Type 503, manufactured by the Hartford Division of Emhart 
Corporation, Hartford, Conn., or the like. 
Referring now to FIG. 1-6, apparatus for forming molten glass into discrete 
gobs comprises orifice ring 10 having a generally circular peripheral 
configuration, a contoured top surface portion 12 and a contoured bottom 
surface portion 14. As best shown in FIGS. 2 and 4-6, the uppermost 
portion of contoured top surface portion 12 is defined in part by the 
uppermost portion 16 of lip 18 extending around the periphery of the 
orifice ring. Rim portion 20 extends radially outwardly from lip 18 and 
has an upper flat surface portion 22 which merges into lip 18 below the 
uppermost surface portion 16 of the lip. The upper flat surface 22 of rim 
portion 20 and the lip 18 are adapted to be placed in sealed engagement 
with a lower outlet opening of a conventional refractory spout (not shown) 
so as to prevent molten glass from escaping over the uppermost porton 16 
of lip 18 during use of the apparatus. 
From the uppermost portion 16 of lip 18, the contoured top surface portion 
12 of the orifice ring extends radially inwardly and axially downwardly 
along sloped, upper surface wall portions 24 to an area adjacent the 
lowermost portions of the top surface of the orifice ring at regions 
generally shown at 26 and to an area in an intermediate portion of the top 
surface portion of the orifice ring at regions generally shown at 28. At 
the intermediate regions shown at 28, the wall portion 24 merges into 
generally flat intermediate surface portions 30, 32 on opposite sides of 
the top surface porton 12 of the orifice ring. The intermediate surface 
portions 30, 32 are interconnected by wall surface portions 34, 36 having 
uppermost surface portions 38, 40, respectively, located in a plane 
including generally flat intermediate surface portions 30, 32. 
From generally flat intermediate surface portions 30, 32, the contoured top 
surface portion 12 of the orifice ring extends radially inwardly and 
axially downwardly along sloped wall surface portions 42, 44, 46, 48 and 
along sloped wall surface portions 50, 52 to areas 54, 56, 58 adjacent the 
lowermost portions of the top surface of the orifice ring. From the 
uppermost surface portions 38, 40 of wall surface portions 34, 36, the 
contoured top surface portion 12 of the orifice ring extends downwardly 
along curved surface wall portions 60, 62, 64, 66 to the areas generally 
shown at 61, 63, 65, 67 adjacent the lowermost portions of the top surface 
of the ring. 
The wall surface portions 24, 30-52 and 60-66 merge at intersecting areas 
so as to provide a continuous surface adapted to permit the free flow of 
molten glass thereover, as will be hereinafter further described. 
The contoured top surface portion 12 of the orifice ring, as previously 
described, defines three reservoir means 68, 70, 72 for receiving and 
temporarily storing molten glass. The reservoir means are oriented in the 
top surface portion of the orifice ring so as to define two end reservoir 
means 68, 72 defined by side wall surfaces 24, 42, 48, 60 and surfaces 24, 
44, 46, 66, respectively, and a middle reservoir means 70 defined by 
sidewall surfaces 50, 52, 62, 64. The middle reservoir means 70 is adapted 
to provide a relatively longer average residence time for molten glass 
than the average residence time in the end reservoir means. This is 
accomplished in the presently preferred and illustrative embodiment of 
FIGS. 1-6 by sizing the middle reservoir means 70 volumetrically 
relatively larger than the end reservoir means 68, 72, such as by 
elongating the sidewall surface portions 62, 64 of the middle reservoir 
means relative to the side wall surface portions 60, 66 of the end 
reservoir means, while maintaining the width and depth of the three 
reservoir means at an approximately uniform level. 
The apparatus further comprises orifice means associated with each 
reservoir means for permitting passage of molten glass through the orifice 
ring. Referring particularly to FIGS. 1, 2 and 4, the orifice means 
comprise orifices 80, 82 associated with the end reservoir means 68, 72, 
respectively, and orifice 84 associated with the middle reservoir means 
70, located in a central bottom portion of the reservoir means. The 
orifices are defined by orifice side walls 86 extending from the lowermost 
surface portions of the reservoir means to the lower surface portion 14 of 
the orifice ring, each orifice preferably having a circular 
cross-sectional peripheral configuration of uniform area wherein the 
orifice side walls 86 are of uniform height, of for example 5/8 in., along 
the perimeter of the orifices providing for uniform flow of molten glass 
past the orifice side walls at any radial location, as will be hereinafter 
further described. 
Referring now to FIGS. 3-7, the contoured bottom surface portion 14 of 
orifice ring 10 is defined in part by uppermost bottom surface portion 100 
of rim portion 20 of the ring, which extends around the periphery of the 
ring beneath upper flat surface 22 of the rim portion 20. From uppermost 
bottom surface portion 100, the contoured bottom surface portion 14 of the 
orifice ring extends radially inwardly and axially downwardly along sloped 
bottom wall portions 102 to areas adjacent the lower portions of the 
bottom surface portion of the orifice ring at regions generally shown at 
104 and to areas in an intermediate portion of the bottom surface portion 
of the orifice ring at areas generally shown at 106. At the areas adjacent 
the lower portions of the bottom surface portion generally shown at 104, 
the wall portion 102 merges into generally flat lower bottom surfaces 107. 
The contoured bottom surface portion is further defined by generally flat 
lower bottom surfaces 108, 110 which are located in a plane including 
surfaces 107. From the surfaces 108, 110 the contoured bottom surface 
portion extends axially downwardly along surfaces 112 and then radially 
inwardly along lowermost generally flat bottom surface portions 114. The 
peripheral configuration of lowermost surface portions 114, as defined by 
surfaces 112, is adapted to be received in and fit through a corresponding 
passagesay in an orifice ring holder means, as will be hereinafter further 
described. 
The plane including surfaces 107, 108 and 110, and the sloping wall portion 
102, are broken by areas of depression 120 in the contoured bottom surface 
portion of the ring adapted to receive and store a suitable insulation 
material for insulating the end reservoir means 68, 72 against thermal 
loss. The plane and sloping wall portion 102 are further broken by sloping 
wall portions 130, 132 interconnected by curved wall portions 133 defining 
first-type substantially parallel elongated channel means 134, 136 is the 
contoured bottom surface portion 14 of the orifice ring extending along 
the outside of the middle reservoir means 70 generally parallel to middle 
reservoir means side wall surfaces 62, 64 and by curved, sloping wall 
portions 138, 140 interconnected by curved wall portions 142 defining 
second-type substantially parallel channel means 144, 146 in the contoured 
bottom surface portion 14 of the ring extending along the outside of the 
middle reservoir means 70 generally parallel to middle reservoir means 
side wall surfaces 50, 52. The sloping wall portions 132 and the curved 
wall portions 140 define the outisde side surface portions of the middle 
reservoir means 70. The second-type channel means intersect the first-type 
channel means at areas generally shown at 148 providing channel means 
extending substantially completely around the outside periphery of the 
middle reservoir means 70. The channel means provide means for cooling the 
middle reservoir means by providing for exposure of the outside side 
surface portions of the middle reservoir means to a suitable coolant, as 
will be hereinafter further described. 
Referring now to FIGS. 8 and 9, the apparatus further comprises orifice 
ring holder means 160 for receiving, seating and holding the orifice ring 
in place during use, having a side wall 162, a bottom wall 164 and coolant 
supply means 166. Holder side wall 162 comprises radially inwardly and 
axially downwardly sloped holder side wall portion 168 having a generally 
circular peripheral cross-sectional configuration and an integral, 
radially inwardly extending flange portion 170. Holder bottom wall 164 
comprises a generally flat wall member 172 having a first-type passageway 
174 through the wall member 172 defined by passageway edge surface 176 and 
being peripherally shaped similarly to and sized slightly larger than flat 
bottom surface portions 114 of orifice ring 10 so as to permit passage of 
the bottom surface portions 114 of the orifice ring therethrough. Holder 
bottom wall 164 is adapted to be fixed to flange portion 170 by suitable 
fastening means, such as rivets 177, or the like. Coolant supply means 166 
for supplying coolant to the channel means of the orifice ring comprises 
conduit means 178 for conveying a coolant therethrough, fluid 
communication means, such as orifices 180, providing fluid communication 
between the conduit means 178 and the channel means of the orifice ring, 
and means, such as a source of pressurized air or other coolant (not 
shown), for supplying coolant to the conduit means. As shown in the 
illustrative embodiment of FIG. 8, conduit means 178 comprises two 
first-type conduits 182, each having a first end portion 184 extending 
through holder side wall 168 and adapted to be suitably connected to the 
source of pressurized air or other coolant, and a second end portion 186 
adapted to be closed, such as with a cap or plug (not shown), to the 
passage of the coolant. The first-type conduits 182 extend in parallel 
relationship substantially across the holder bottom wall 164 and may be 
fixed thereto such as by mounting clips 188. Conduit means 178 further 
comprises two second-type conduits 190 interconnected with and providing 
fluid communication between the two first-type conduits 182 on opposite 
sides of the bottom wall first-type pasageway 174. The arrangement of the 
two first-type conduits 182 and the two second-type conduits 190 with 
respect to holder means 160 is such that when orifice ring 10 is received 
and seated in the holder means 160 with the flat bottom surface portions 
114 of the orifice ring extending through the first-type passageway 174 of 
the holder means, the first-type conduits 182 are received in the 
first-type channel means 134, 136 in the bottom surface of the orifice 
ring, the second-type conduits 190 are received in the second-type channel 
means 144, 146 in the bottom surface portion of the orifice ring, and 
orifices 180 are located in the first-and second-type conduits so as to 
supply and disperse coolant across the outside side surface portions of 
the middle reservoir means of the orifice ring. 
The holder means preferably further comprises escape means for allowing 
escape of coolant from the holder means during use of the apparatus. 
Referring to FIG. 8, the escape means may comprise at least one, and 
preferably two, second-type passageways 200 through the holder means 
bottom wall 164 providing fluid communication between the orifice ring 
receiving side of the holder means and the outside of the holder means 
when the orifice ring is received by and seated in the holder means. The 
peripheral configuration of the second-type passageways 200, as defined by 
second-type passageway edge surface 202, preferably corresponds to the 
configuration of the second-type channel means 144, 146, and the 
second-type passageways are preferably oriented in proximity to the 
second-type channel means when the orifice ring is seated in the holder 
means so as to provide for free flow of coolant from the conduit means 
through the channel means, and then out of the holder means through the 
second-type passageways. 
In use of the apparatus as previously described, orifice ring 10 is seated 
in holder means 160 with thermal insulation packing material placed in, 
and preferably filling, the areas of depression 120 in the contoured 
bottom surface portion 14 of the orifice ring. A sealant is then placed on 
the flat surface portion 22 or orifice ring rim 20 and the orifce ring and 
holder means is clamped to the bottom of a conventional refractory spout. 
The conduit means 178 are then connected to a coolant supply, such as a 
source of pressurized air. While for reasons of economy, pressurized air 
is the presently preferred coolant, other suitable coolants include 
relatively non-flamable gases and liquids. 
Molten glass is supplied to the refractory spout from a conventional 
forehearth and regulated amounts of the molten glass are permitted to flow 
into proximity of the spout discharge opening to cover the contoured upper 
surface portion of the orifice ring by raising and lowering a conventional 
spout tube. Plungers located in the spout tube in axial alignment with 
orifices 80, 82, 84 are raised and lowered a regulated distance, and at a 
regulated rate, to urge a portion of the molten glass through orifices 80, 
82, 84 to form the molten glass into three rod-like molten glass members 
of generally uniform cross-sectional configuration. Shears located a 
regulated distance beneath the orifice ring and holder means then shear 
the molten glass rod-like members into discrete gobs of a desired size, 
which are transported to suitable forming apparatus for forming the gobs 
into a finished article, such as a bottle or jar. 
In order to obtain uniform gob size and shape, the conditions to which the 
molten glass is subjected as it passes through orifices 80, 82, 84 must be 
the same, or closely similar, for each orifice. However, as previously 
described, molten glass in the end reservoir means 68, 72 tends to 
experience a greater temperature loss prior to flowing through orifices 
80, 82 then molten glass in the middle reservoir means 70 due to the 
proximity of the end reservoir means to the sides of the orifice ring. The 
present method and apparatus thus provides for equalization of molten 
glass temperatures by providing two end reservoir means of similar size, 
configuration and orientation for maintaining the average residence time 
of molten glass at a relatively constant level, and a middle reservoir 
means sized relatively larger than the end reservoir means for maintaining 
the average residence time of molten glass in the middle reservoir means 
at a relatively constant level which is longer than the averge residence 
time in the end reservoir means, thereby permitting a longer cooling 
period for molten glass in the middle reservoir means. The molten glass in 
the middle reservoir means is further cooled by flowing a coolant over the 
outside side surfaces of the middle reservoir means, as hereintofore 
described. The nature and amount of coolant utilized to cool the middle 
reservoir means is optimally designed to obtain a uniform, desired 
temperature of the molten glass flowing through the orifices 80, 82, 84. 
The method and apparatus described herein allow production of molten glass 
gobs having a uniform molten glass viscosity in a triple gob feeder, 
resulting in uniform cooling temperature profiles for gobs produced from 
each orifice. In addition, since the gob formation temperatures are 
equalized at all three orifices, the gobs produced are of a uniform size 
and configuration, thereby enhancing the uniformity and quality of the 
desired end product. 
While the foregoing method and apparatus has been described in association 
with a presently preferred illustrative embodiment, various modifications 
may be made without departing from the inventive concepts. Such 
modifications are intended to be within the scope of the appended claims 
except insofar as limited by the prior art.