Note: Descriptions are shown in the official language in which they were submitted.
CA 02459781 2004-03-30
ADAPTER MEMBER FOR CONNECTING EXTRUDERS
This application is a divisional of Canadian Patent
Application No. 2,346,112 filed November 5, 1998.
TECHNICAL FIELD
The invention is directed to an apparatus and
method for the processing of polyvinyl acetate for use in
chewing gum and chewing gum bases.
BACKGROUND OF THE INVENTION
There are several systems known today for producing
chewing gum bases and the final chewing gum products.
Typically, a chewing gum base is made separately from the
final chewing gum, although there are some systems which are
capable of producing a final chewing' gum product in one
continuous process.
In general, a chewing gum composition typically
comprises a water-soluble bulk portion, a water-insoluble
chewing gum base portion, and typically water-insoluble
flavoring agents. The insoluble gum base generally comprises
elastomers, elastomer solvent, fillers, resins, polyvinyl
acetate (PVA), fats, plasticizers, waxes, emulsifiers, and
other miscellaneous ingredients. The water-soluble portion
dissipates with a portion of the flavoring agent over a
period of time during chewing. The gum base portion is
retained in the mouth throughout the time that the product
chewed.
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Numerous chewing gums and chewing gum bases are
produced using a batch method. Sigma blade batch mixers are
typically used for this conventional process. The gum base
ingredients are added either separately or simultaneously
into the batch mixer and the material is then melted and
mixed over time. After the gum base is processed, the molten
gum base batch is emptied into coated or lined pans, or
pumped to other equipment such as holding tanks or a filling
device, then extruded or cast into shapes, and allowed to
cool and solidify, before being ready for use in chewing gum.
The final chewing gum product can also be processed
using a batch method. A portion of the gum base, together
with softeners and bulking agents, such as sugars or sugar
alcohols, are added to the mixer. Latex, flavorings such as
flavored oils and/or spray-dried flavors, sweeteners or acids
are added while mixing is continued until a homogeneous mass
is achieved. Delivery systems of this type are shown, for
example, in U.S. Patents Nos. 4,816,265, 5,000,965 and
5,057,328. The chewing gum mass is then cooled and later
rolled, scored, and wrapped into the final product.
Continuous extrusion machines can also be used for
producing chewing gum bases or the final chewing gum
products, or both. The use of continuous extruders to make
a final chewing gum product are shown, for example, in U.S.
Patent No. 5,135,760 to Degady et al.; U.S. Patent No.
5,045,325 to Lesko et al.; and U.S. Patent No. 4,555,407 to
Kramer et al. Processes known in the art for continuously
producing a chewing gum base with the use of a continuous
extrusion machine are shown, for example, in U.S. Patents
Nos. 5,419,919 and 5,486,366, both to Song et al.
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The continuous gum base and chewing gum product
processes disclosed in these patents typically utilize a
continuous extrusion machine, such as a twin-screw extruder.
These extruders typically have several different feed inlets
where the ingredients are added. The elongated screws inside
the barrels of the extruders are equipped with different
types of elements. Continuous extrusion machines which can
be used for producing chewing gum bases and final chewing gum
products include extruders from Togum, Baker Perkins, Werner
to & Pfleiderer Corp., Japan Steel Works, Leistriztz, WLS and
Buss Mfg. Co.
Whether a batch-type process or a continuous
extruder-type process is used to produce the chewing gum and
gum base products, it is important to provide the various
ingredients for these products in the best form and
condition. This improves the speed and efficiency of the
final processing, and also improves the uniformity and
consistency of the final product. In this regard, ingredients
such as fillers, elastomers, plasticizers, resins, PVA, oils,
waxes, and the like, often require special handling or
preparation prior to being included in the batch or extrusion
process.
Preparation of the ingredients is especially
important where continuous extrusion processing is utilized.
The ingredients applied to the continuous extrusion apparatus
are preferably provided in the optimum size, shape, condition
(liquid, solid, etc.), and temperature for ease of insertion
and intermixing with the other ingredients in the extruder.
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In order to achieve a homogeneous phase gum base
or gum product wherein a proper resiliency is constant
throughout and the product is free from lumps and other
irregularities, it is necessary to provide the ingredients
which are compatible with one another and are as dispersed
and distributed as much as possible in the materials being
processed. Processing and environmental conditions, such as
temperature, humidity, and the like, must also be considered
and taken into account in preparing a useable gum or gum base
product.
Several of the ingredients typically used in
chewing gum and gum base products, such as elastomers, solid
resins, plasticizers and elastomeric solvents, are often
difficult to handle and process. One material commonly used
in the chewing gum products is polyvinylacetate (PVA). This
material can be used as a resin, plasticizer or elastomer
solvent for the gum and gum base products. A plasticizer is
often also referred to as a softener.
PVA material is typically provided in solid form,
namely as individual wafers, pastilles, pellets or small
pieces packed in a bag or other container. That material,
which is tacky and thus difficult to process with automatic
equipment, typically needs to be inserted into a continuous
extrusion machine in individual small pieces. Also, it is
often necessary to insert PVA and similar materials through
a side feeder into the main extruder. In this manner, the
material can be inserted in solid small particle form at the
appropriate point or stage of the extrusion process. Side
feeders of this type are available, for example, from Buss
Mfg. Co., Werner & Pfleiderer Corp. and Baker Perkins.
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Further, when using a side feeder, it is often
difficult to clean or maintain the feeder apparatus without
physically moving the entire apparatus away from the main
extruder.
S It is a general object of the present invention to
provide an improved method and apparatus for the production
of chewing gum products and gum base products. It is also an
object of the present invention to provide improved apparatus
and methods for preparation of certain chewing gum and gum
l0 base ingredients prior to processing in order to facilitate
improved processing and an improved final product.
It is still another object of the present invention
to provide a method and apparatus for continuously preparing
chewing gum bases and products which have a consistent and
15 uniform composition. It is another object of the present
invention to provide an improved process and apparatus for
supplying chewing gum base and chewing gum product
ingredients, particularly PVA, to a continuous extruder in
an optimum condition and form in order to provide a
20 consistent and uniform final product, wherein an improved
adapter mechanism for operationally connecting a side feeder
extrusion apparatus to a main extrusion apparatus is
employed.
These and other objects, benefits, and advantages
25 are met by the following description of a preferred form of
the invention.
CA 02459781 2004-03-30
SUML~iARY OF THE INVENTION
The present invention relates to an apparatus and
process for producing a gum base and the final chewing gum
product. A novel process and apparatus and system are used
to handle and process several of the hard-to-handle
ingredients for a continuous gum making system. These
ingredients include, for example, resins, plasticizers and
elastomeric solvents, including, in particular,
polyvinylacetate (PVA).
A low-speed lump breaking apparatus is utilized to
break up and divide the PVA or like material into small
individual pieces. The lump breaker has a rotating blade
which separates the particles into their original individual
piece or wafer-like form. The removed material is
pneumatically conveyed to a feeding system for a side feeder
to the main extruder. The material is stripped from the
pneumatic conveying air by a cyclone receiver and fed by
gravity into a holding receiver. The holding receiver acts
as a holding bin which releases the material through a
computer control valve and a volumetric loss-in-weight
feeder.
A magnetic metal detector is used to remove any
metallic impurities from the material. The material is
inserted into the barrel of the main extruder and intermixed
and intermelted with the molten mass to form the final gum
base or chewing gum product.
Throughout the process, the material is kept at a
low temperature and is physically and manually handled as
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little as possible. In this manner, the material, such as
PVA, remains in a solid, unmelted condition and is eventually
conveyed into the main extruder in the desired condition for
further processing.
In accordance with the present invention, an
adapter mechanism is used to connect and join together the
side feeder with the main extruder. The adapter allows the
elongated shafts in the side feeder to be retracted and
maintained without separation of the two extruders.
l0 With the disclosed process and apparatus and
system, a better quality final product is secured. The
extrusion process is more consistent since the rates of speed
and temperatures in the various stages of the extruder and
the ingredients are kept to their optimum level for further
processing.
These and other features, advantages and benefits
to the present invention will become apparent from a review
of the following description, when taken in view of the
accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic diagram of a chewing gum
or gum base process in accordance with the present invention;
FIGURE 2 is a schematic diagram of a PVA processing
system in accordance with the present invention;
FIGURE 3 is a flow diagram of a PVA processing
system in accordance with the present invention;
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FIGURE 4 is a schematic drawing of a lump breaker
apparatus in accordance with the present invention; and
FIGURES 5-7 illustrate an unique adapter mechanism
for use with the present invention.
Best Modes For Carrying Out The Invention
The present invention is particularly suitable for
processing solid ingredients, such as polyvinylacetate (PVA),
for use in chewing gum bases and chewing gum products. In
general, the present invention provides an apparatus, method and
system for processing the ingredients in order to facilitate
their introduction into a chewing gum base or chewing gum
product in an optimum manner and condition. This optimum
condition allows the chewing gum or gum base manufacturing
process to provide a more consistent and uniform final product.
In this regard, it is to be understood that the
present invention can be used for preparing the solid components
of either a chewing gum base or a final chewing gum product and
can be used with either a batch-type system or a continuous
extruder-type system. In the preferred embodiment of the
present invention, however, and for ease in illustrating the
present invention, it will be described herein with reference
to its use in a continuous gum base manufacturing system.
Schematic illustrations of the apparatus and system
of the present invention are illustrated in Figures 1 and 2.
A flow chart illustrating the basic processing steps of the
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present invention is depicted in Figure 3, and a lump breaker
apparatus for use with the present invention is shown in Figure
4. Finally, Figures 5-7 illustrate an unique adapter mechanism
for use in connecting a side feeder to a main extruder in
accordance with the present invention.
It is known today to use continuous extruding
equipment to produce chewing gum bases and final chewing gum
products. An extruder 10 of this type is illustrated in Figure
1. The extruder, which can be of any conventional type, has a
motor and control mechanism 12 and an elongated barrel member
14. The continuous extrusion can be of conventional type from
any extruder manufacture known today, such as Japan Steel Works,
Leistriztz, Werner & Pfleiderer Corp., Togum, WLS, Baker Perkins
and Buss Mfg. Co.
Typically, the continuous extrusion machines use
twin-screw extruders which are either co-rotational, counter-
rotational, intermeshing or tangential. These extruders have
one or two elongated screw members in the barrels 14 which
intermix and process the ingredients and materials for the gum
base and/or the final gum product. The elongated screw members
have different types of screw elements on them for processing
the materials. The most common types of screw elements include
conveying elements, compression elements, reverse conveyance
elements, homogenizing elements such as shearing disks and tooth
elements, and kneading disks and kneading blocks. These
elements, and other elements typically used in extruding
machines; especially twin-screw extruders, are well known in the
art and commercially available. The elements are often
specifically designed for the particular type of extruder
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utilized and the particular type of ingredients utilized in the
final desired product.
The extruders typically have several different feed
inlets where the ingredients are added. For example, as shown
in Figure 1, the extruder 10 has a first feed inlet I6 and two
other inlets 18 and 20 positioned downstream on the barrel.
Typically, solid ingredients, such as elastomers, fillers, and
elastomer solvents, and plasticizers are introduced into the
barrel through inlet port 16. Other ingredients, usually in a
liquid condition, are added in the downstream ports 18 and 20.
These other ingredients include waxes, oils, and the like.
In order to introduce certain resins, PVA, plasti-
cizers and/or elastomeric solvents, also in a solid condition,
to the extrusion process, it is often desirable to utilize a
side feeder, such as the side feeder 22 shown in Figure 1. In
this regard, the side feeder can be any conventional extrusion
apparatus, such as those available from Buss Mfg. Co., Baker
Perkins and Werner & Pfleiderer Corp. The side feeder has a
motor and control mechanism 24 and an elongated barrel 26. An
inlet chute 28 is used to supply materials to the side feeder.
The side feeder 22 is connected to the main extruder
with an adapter mechanism 30. (Further details of the adapter
mechanism 30 are discussed below with reference to Figures 5-7).
Also, the barrel of the side feeder has an upper and lower
section, indicated by reference numerals 26A and 26B,
respectively. A single or twin-screw mechanism (not shown) is
positioned in the barrel 26 of the side feeder 22. Upper
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section 26A of the barrel housing is adapted to be pivoted or
removed in order to allow access to the elongated screws.
The preferred process and system for the PVA and like
materials in order to prepare them for input into the inlet port
28 of the side feeder 22 is shown in Figure 2. A lump breaking
apparatus or mechanism 40 is used to separate and prepare the
materials for conveying to a cyclone receiver 42 and a holding
receiver 44. In this regard, the material is conveyed from the
lump breaking mechanism 40 to the cyclone receiver 42 by air
conveying system 46. The cyclone receiver strips the pneumatic
conveying air from the material and feeds the material by
gravity through a valve member 48 into the holding receiver 44.
The receiver 44 acts as a holding bin which releases the
material by a computer-controlled valve 49 to a loss-in-weight
(LIW) feeder 50. The LIW feeder 50 retains the material in the
hopper 44 until it is needed in the side feeder 22 and main
extruder 12. A magnetic metal detector 52 is used to separate
metal impurities from the flow of material as it passes from the
feeder 50 into the inlet chute 28 of the side feeder.
A blower 43 is used to exhaust air from the cyclone
receiver (a/k/a centrifugal separator) 42. The air in the
blower is vented to the atmosphere.
The details of the lump breaker mechanism 40 are
depicted in Figures 2 and 4. The mechanism 40 includes an inlet
chute or housing 60, a main body 62, and a lower conveying
section 64. The open end 66 of the inlet housing 60 is covered
by a grate 68. ~A rotating separator/lump breaker member 70 is
positioned in the main body section 62. The rotating separator
operates at a low speed and is controlled by a motor and
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controlling mechanism 72. A grate 74 is positioned below the
separator 70 and separates the main body housing 62 from the
conveying section 64.
In the operation of the lump breaker 40, bags of
solid particulate material 80 are opened above the grate 68 and
the contents 82 dropped onto and through the grate. If the
material is polyvinylacetate (PVA), it is typically provided in
small wafer-like pieces. However, due to the consistency and
melt temperature of
PVA material, the wafers are typically massed and stuck together
and thus the material is removed from the bags 80 in various
size lumps, for the most part.
The lumps of material 82 are manually and physically
pushed through the grate 68 and into the inlet chute 60. The
lumps are then dropped onto the rotating separator 70 which
agitates and divides the wafer-like materials into individual
pieces. The individual pieces are then passed in turn through
grate 74 into the conveying section 64. At that point, the
wafer members are transported from the conveying section 64 by
the air conveying system 46.
A flow chart showing the basic processing steps of
the present invention is shown in Figure 3. The PVA material
is first introduced into the lump breaker 40 where it is divided
and separated into its individual particles or pieces. From
there, the individual pieces are conveyed through pneumatic
conveying system 46 to the cyclone receiver 42. From there, the
materials are fed by gravity to hopper or holding bin 44.
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Loss-in-weight (LIW) feeder 50 regulates the flow of
the PVA material into the side feeder 22. A magnetic or metal
detector 52 is used to separate impurities from the PVA material
at that point. It is also possible to include a lubrication or
dusting agent, such as talc, atomite, dicalcium phosphate or the
like, to the PVA pieces. The lubricating agent can be added at
any point in the inventive process and can be accomplished with
use of any conventional feeder apparatus, such as apparatus 55
in Figure 2.
Once the material is in the side feeder, it is
conveyed by the elongated screws in the barrel 26 to the main
extruder 10. At this point, other ingredients and components
88 for the final chewing gum base or chewing gum product are
added to the main extruder. The final product 90 is extruded
from the extruder 10.
In accordance with the present invention, the side
feeder unit 22 is preferably capable of feeding 2000 pounds per
hour of resin material to the main feeder. At the same time,
the present inventive system, including the side feeder,
maintains the material in a cooled condition sufficient to
maintain a consistent and uniform feed into the continuous
processor.
In accordance with the present invention, it is
important to handle the material as little as possible and
prevent heat from being generated in the system. For this
purpose, the air used with the pneumatic conveying system 46 is
kept at a cool or law temperature, for example, 50° to 75°F.
Also, the corners or curves in the conveying system 46, such as
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corners 47A, 47B and 47C in Figure 2, are kept at a large
radius. A large radius is used in order to allow the material
to pass through the conveying conduits more quickly and without
significant resistance which might generate unacceptable heat.
With the present invention, the PVA material is
separated into solid members (wafers, pastilles, pellets, or the
like), maintained in that separated condition throughout the
system, and then introduced into the main extruder also in that
same condition. By controlling the temperature throughout the
process, and providing the material in a separated state, the
rate of feed of the material and the amount of material added
to the main extruder can be precisely controlled. This results
in a better quality and more uniform and consistent final
product.
Preferably, the major components of the system are
made of a stainless steel material. This includes at least the
lump breaker mechanism 40, the conduits used in the conveying
2o system 46, the cyclone receiver 42, the receiver 44, and the
loss-in-weight feeder 50. Also, as part of the temperature
control system, the cyclone receiver 42 and holding receiver 44
are cooled by external water jackets 43 and 45, respectively.
The details of the unique adapter 30 for use in the
present invention are shown in Figures 5-7. The adapter 30 has
a main block or body member 92 and a protruding interconnector
member 94. The interconnector member 94 has a generally "figure
8°-shaped opening 96 which facilitates passage of material from
the twin-screws of the side feeder 22 into the main extruder.
The front curved surface 98 of the interconnecting member 94
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is shaped to blend in with the side of the main opening or
passageway in the barrel 14 of the main extruder 10. A
plurality of openings 100 are provided in the body 92 for
connecting the adapter 30 to the side feeder 22 and main
extruder 10. Bolts or other fasteners are positioned in the
openings 100 and used to connect the two extruders and adapter
together.
With the use of the adapter 30, the screws and other
elements in the barrel 26 of the side feeder 22 can be removed
and worked on without moving the side feeder relative to the
main extruder. In this manner, changes and repairs can be made
to the side feeder, motor, and control mechanism 24 and the
barrel 26 without having to move any parts of the side feeder
away from the main extruder or having to disturb any of the
cooling lines, connectors and other electrical conduits and
lines. In particular, this adapter 30 allows the screw member
and shafts in the barrel in the side feeder to be retracted and
removed without separation of the side feeder from the main
extruder. This saves space in the manufacturing facility and
also makes repair and modification of the side feeder to be done
more easily and at less cost.
While there have been described what are presently
believed to be the preferred embodiments of the invention, those
skilled in the art will realize that changes and modifications
may be made thereto without departing from the spirit and scope
of the invention, and it is intended to claim all such changes
and modifications that fall within the true scope of the
invention as defined and covered by the following claims.
