U.S. patent application number 10/430979 was filed with the patent office on 2004-08-05 for system and method for directing a fluid through a die.
This patent application is currently assigned to Crane Plastics Company LLC. Invention is credited to Brandt, Jeffrey R., Hutchison, Herbert L., Kollar, Matthew F., Zehner, Burch E..
Application Number | 20040148965 10/430979 |
Document ID | / |
Family ID | 33449641 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040148965 |
Kind Code |
A1 |
Hutchison, Herbert L. ; et
al. |
August 5, 2004 |
System and method for directing a fluid through a die
Abstract
The present invention relates to a system and method for
directing a fluid through a die. One embodiment of the present
invention is especially useful to thoroughly cool an extrudate by
directing a cooling fluid toward a surface of the extrudate (e.g.,
an interior surface that defines a hollow portion of an extrudate).
In another embodiment of the present invention, a fluid may be
directed through a die for forming a layer or portion of a product.
More particularly, a fluid may be directed through a die to form an
external or core layer of a product from a foamed or unfoamed
material including, but not limited to, a cellulosic-filled plastic
composite. For example, the present invention includes a system and
method for through the die foaming of extruded products.
Inventors: |
Hutchison, Herbert L.;
(Blacklick, OH) ; Brandt, Jeffrey R.; (Blacklick,
OH) ; Zehner, Burch E.; (Gahanna, OH) ;
Kollar, Matthew F.; (Powell, OH) |
Correspondence
Address: |
STANDLEY LAW GROUP LLP
495 METRO PLACE SOUTH
SUITE 210
DUBLIN
OH
43017
US
|
Assignee: |
Crane Plastics Company LLC
Columbus
OH
|
Family ID: |
33449641 |
Appl. No.: |
10/430979 |
Filed: |
May 7, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10430979 |
May 7, 2003 |
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10280735 |
Oct 25, 2002 |
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10280735 |
Oct 25, 2002 |
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10131578 |
Apr 24, 2002 |
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6637213 |
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10131578 |
Apr 24, 2002 |
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10025432 |
Dec 19, 2001 |
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6708504 |
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10025432 |
Dec 19, 2001 |
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09766054 |
Jan 19, 2001 |
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6578368 |
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Current U.S.
Class: |
62/630 ; 62/62;
62/64 |
Current CPC
Class: |
B29C 44/22 20130101;
F25B 9/002 20130101; B29C 48/304 20190201; B29C 48/11 20190201;
B29C 48/09 20190201; B29C 48/49 20190201; B29C 48/12 20190201; B29C
48/904 20190201; B29C 2035/165 20130101; B29L 2031/60 20130101;
B29C 48/34 20190201; B29C 35/16 20130101; B29C 48/908 20190201;
B29C 48/919 20190201; B29C 48/9115 20190201; B29C 2035/1616
20130101; B29K 2001/00 20130101; B29C 2035/1658 20130101 |
Class at
Publication: |
062/630 ;
062/064; 062/062 |
International
Class: |
F25D 013/06; F25J
003/00; F25D 025/00; F25D 017/02 |
Claims
What is claimed is:
1. A method for directing fluid through a die, said method
comprising: providing a die, said die having a flow channel and a
passage, said passage lined with an insulating material; extruding
a material through said flow channel; directing a fluid through
said passage; forming a product of said material extruded through
said flow channel, said product having a hollow; and releasing said
fluid from said passage into said hollow of said product.
2. The method of claim 1 wherein said insulating material is
selected from the group consisting of ceramic insulation and putty
ceramics.
3. The method of claim 1 wherein said material is a
cellulosic-filled plastic composite.
4. The method of claim 1 wherein said fluid is a cellulosic-filled
plastic composite.
5. The method of claim 1 wherein said fluid is a foamed
plastic.
6. The method of claim 1 wherein said fluid is a cooling fluid.
7. The method of claim 6 wherein said cooling fluid has a
temperature between about 80 degrees Fahrenheit and about minus 325
degrees Fahrenheit.
8. The method of claim 6 wherein said cooling fluid has a
temperature between about 68 degrees Fahrenheit and about minus 300
degrees Fahrenheit.
9. The method of claim 6 wherein said cooling fluid has a
temperature between about 32 degrees Fahrenheit and about minus 275
degrees Fahrenheit.
10. The method of claim 6 wherein said cooling fluid has a
temperature between about minus 100 degrees Fahrenheit and about
minus 250 degrees Fahrenheit.
11. The method of claim 6 wherein said cooling fluid is selected
from liquid oxygen, liquid nitrogen, liquid neon, liquid hydrogen,
and liquid helium.
12. The method of claim 6 wherein said cooling fluid is selected
from the group consisting of liquids, gases, and vapors.
13. The method of claim 1 wherein said fluid is extruded through
said passage.
14. The method of claim 1 wherein said passage intersects said flow
channel.
15. A die adapted to be used with at least one extruder, said die
comprising: a flow channel adapted to receive extruded material and
form a product having a hollow; and a passage adapted to receive a
fluid, said passage lined with an insulating material; wherein said
passage is adapted to release said fluid in said hollow of said
product.
16. The die of claim 15 wherein said insulating material is
selected from the group consisting of ceramic insulation and putty
ceramics.
17. The die of claim 15 wherein: said flow channel is adapted to be
in fluid communication with a first extruder; and said passage is
adapted to be in fluid communication with a second extruder.
18. A die adapted to be used with at least one extruder, said die
comprising: a flow channel adapted to receive extruded material and
form a product having a hollow; and a passage intersecting said
flow channel, said passage adapted to receive a fluid, said passage
lined with an insulating material; wherein said passage is adapted
to release said fluid in said hollow of said product.
19. The die of claim 18 wherein said insulating material is
selected from the group consisting of ceramic insulation and putty
ceramics.
20. The die of claim 18 wherein: said flow channel is adapted to be
in fluid communication with a first extruder; and said passage is
adapted to be in fluid communication with a second extruder.
Description
[0001] This is a continuation-in-part of U.S. application Ser. No.
10/280,735, filed October 25, 2002, which is a continuation-in-part
of U.S. application Ser. No. 10/131,578, filed Apr. 24, 2002, which
is a continuation-in-part of U.S. application Ser. No. 10/025,432,
filed Dec. 19, 2001, which is a continuation-in-part of U.S.
Application No. 09/766,054, filed Jan. 19, 2001, each of which is
hereby incorporated by reference in its entirety.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The present invention relates generally to a system and
method for directing a fluid through a die. One embodiment of the
present invention is a system and method for cooling extruded and
molded materials with a fluid that is below about 80 degrees
Fahrenheit. Another embodiment of the present invention is a system
and method for directing a fluid through a die, such as for cooling
a product or forming a layer or portion of a product.
[0003] For several reasons, there is a need to find materials that
exhibit the look and feel of natural wood. The supply of wood in
the world's forests for construction and other purposes is
dwindling. Consequently, the supply of wood from mature trees has
become a concern in recent years, and the cost of wood has risen.
As a result, several attempts have been made by others to find a
suitable wood-like material.
[0004] cooling methods. Accordingly, the present invention can more
thoroughly and efficiently cool the manufactured product or article
to a desired level. This can lead to faster production times as
well as a product having improved structural, physical, and
aesthetic characteristics.
[0005] In addition to cooling extruded or molded materials, the
present invention may also be used in other types of manufacturing
techniques in which the output or material must be cooled from a
heated state. The present invention includes a system and method
for cooling synthetic wood composite materials including, but not
limited to, cellulosic-filled plastic composites. In addition, the
present invention may also be used to cool other types of pure or
mixed materials including, but not limited to, plastics, polymers,
foamed plastics, plastic compositions, inorganic-filled plastic
compositions, metals, metallic compositions, alloys, mixtures
including any of the aforementioned materials, and other similar,
conventional, or suitable materials that need to be cooled after
being processed. For instance, the present invention may be used to
cool polyvinyl chloride (PVC) products and products made from other
plastics.
[0006] The present invention also includes a system and method for
directing a fluid through a die. In one embodiment, a fluid may be
directed through a die for cooling purposes. In another embodiment,
a fluid may be directed through a die for forming a layer or
portion of a product. More particularly, a fluid may be directed
through a die to form an external or core layer of a product from a
foamed or unfoamed material including, but not limited to, a
cellulosic-filled plastic composite. For example, the present
invention includes a system and method for through the die foaming
of
[0007] Cellulosic/polymer composites have been developed as
replacements for all-natural wood, particle board, wafer board, and
other similar materials. For example, U.S. Pat. Nos. 3,908,902,
4,091,153, 4,686,251, 4,708,623, 5,002,713, 5,055,247, 5,087,400,
5,151,238, 6,011,091, and 6,103,791 relate to processes and/or
compositions for making wood replacement products. As compared to
natural woods, cellulosic/polymer composites offer superior
resistance to wear and tear. In addition, cellulosic/polymer
composites have enhanced resistance to moisture, and it is well
known that the retention of moisture is a primary cause of the
warping, splintering, and discoloration of natural woods. Moreover,
cellulosic/polymer composites may be sawed, sanded, shaped, turned,
fastened, and finished in the same manner as natural woods.
Therefore, cellulosic/polymer composites are commonly used for
applications such as interior and exterior decorative house
moldings, picture frames, furniture, porch decks, deck railings,
window moldings, window components, door components, roofing
structures, building siding, and other suitable indoor and outdoor
items. However, many attempts to make products from
cellulosic/polymer composite materials have failed due to poor or
improper manufacturing techniques.
[0008] In one embodiment of the present invention, a product or
article may be manufactured by a desired technique such as, but not
limited to, extrusion, compression molding, injection molding, or
other similar, suitable, or conventional manufacturing techniques.
The product is then cooled by subjecting it to a cooling fluid
including, but not limited to, direct contact with a liquid
cryogenic fluid. The present invention can be used alone or in
conjunction with other known or later developed extruded products.
For instance, a core foam layer may be formed using an exemplary
system and method of the present invention. Like the other
embodiments of the present invention, this embodiment may be used
with other types of pure or mixed materials including, but not
limited to, plastics, polymers, foamed plastics, plastic
compositions, inorganic-filled plastic compositions, metals,
metallic compositions, alloys, mixtures including any of the
aforementioned materials, and other similar, conventional, or
suitable materials that may be processed through a die. For
instance, the present invention may be used to manufacture
polyvinyl chloride (PVC) products and products made from other
plastics.
[0009] In addition to the novel features and advantages mentioned
above, other objects and advantages of the present invention will
be readily apparent from the following descriptions of the drawings
and exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross sectional view of an extrudate.
[0011] FIG. 2 is a view of an extrusion die showing an exemplary
location of a nozzle.
[0012] FIG. 3 is an elevation view of one embodiment of a system
implementing the present invention.
[0013] FIG. 4 is a partial cross sectional view along the line A-A
of FIG. 3.
[0014] FIG. 5 is a partial elevation view of another embodiment of
a system of the present invention.
[0015] FIG. 6 shows a sectioned schematic of an extruder line used
in accordance with the practice of one embodiment of the present
invention.
[0016] FIG. 7 is a cross sectional view from a lateral side angle
of an exemplary die of the present invention.
[0017] FIG. 8 is a cross sectional view from a top side angle of
the die of FIG. 7.
[0018] FIG. 9 is a cross sectional view from an exit side angle of
the die of FIG. 7.
[0019] FIG. 10 is a cross sectional view from a lateral side angle
of an exemplary die of the present invention that includes a
baffle.
[0020] FIG. 11 is a cross sectional view from a lateral side angle
of another exemplary die of the present invention that includes a
baffle.
[0021] FIG. 12 is a schematic view of an exemplary embodiment of a
system of the present invention that enables direct cooling by a
liquid cryogenic fluid.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)
[0022] The present invention is directed to a system and method for
cooling manufactured articles or products. The present invention is
also directed to a system and method for directing a fluid through
a die. It is not intended to limit the present invention to
particular manufacturing techniques or particular materials. The
present invention may be used in conjunction with articles or
products made by a variety of different manufacturing techniques.
Examples of manufacturing techniques that may utilize the present
invention include, but are not limited to, extrusion (including
co-extrusion), compression molding, injection molding, and other
known, similar, or conventional techniques for manufacturing
products or articles from plastic, wood, metal, mixtures of these
materials, or other materials used to make products.
[0023] The present invention is particularly useful with plastics,
polymers, and cellulosic/polymer composite materials that have been
extruded or molded. The materials that may be used to make
cellulosic/polymer composites include, but are not limited to,
cellulosic fillers, polymers, plastics, thermoplastics, inorganic
fillers, cross-linking agents, lubricants, process aids,
stabilizers, accelerators, inhibitors, enhancers, compatibilizers,
blowing agents, foaming agents, thermosetting materials, and other
similar, suitable, or conventional materials. Examples of
cellulosic fillers include sawdust, newspapers, alfalfa, wheat
pulp, wood chips, wood fibers, wood particles, ground wood, wood
flour, wood flakes, wood veneers, wood laminates, paper, cardboard,
straw, cotton, rice hulls, coconut shells, peanut shells, bagass,
plant fibers, bamboo fiber, palm fiber, kenaf, flax, and other
similar materials. In addition to PVC, examples of polymers include
multilayer films, high density polyethylene (HDPE), polypropylene
(PP), low density polyethylene (LDPE), chlorinated polyvinyl
chloride (CPVC), acrylonitrile butadiene styrene (ABS), ethyl-vinyl
acetate, other similar copolymers, other similar, suitable, or
conventional thermoplastic materials, and formulations that
incorporate any of the aforementioned polymers. Examples of
inorganic fillers include talc, calcium carbonate, kaolin clay,
magnesium oxide, titanium dioxide, silica, mica, barium sulfate,
acrylics, and other similar, suitable, or conventional materials.
Examples of thermosetting materials include polyurethanes, such as
isocyanates, phenolic resins, unsaturated polyesters, epoxy resins,
and other similar, suitable, or conventional materials.
Combinations of the aforementioned materials are also examples of
thermosetting materials. Examples of lubricants include zinc
stearate, calcium stearate, esters, amide wax, paraffin wax,
ethylene bis-stearamide, and other similar, suitable, or
conventional materials. Examples of stabilizers include tin
stabilizers, lead and metal soaps such as barium, cadmium, and
zinc, and other similar, suitable, or conventional materials. In
addition, examples of process aids include acrylic modifiers and
other similar, suitable, or conventional materials.
[0024] FIG. 1 shows one example of an extrudate 100 that may be
cooled by the present invention. The extrudate 100 includes an
exterior surface 102, a hollow 104, an interior surface 106, and
two ends 108. The exterior surface 102 may be cooled by a
traditional method such as using a warm water bath or water mist.
However, the interior surface 106 may not be sufficiently cooled by
many traditional methods because the surface may not be available
for contact with the cooling medium. The interior surface 106
defines the boundary of the hollow 104. It should be recognized
that a product may have a plurality of hollows. The interior
surface 106 may be accessed from either end 108. The interior
surface 106 may not be cooled to a desired level within a desired
amount of time by externally applied coolants.
[0025] In the present invention, a fluid may be directed into the
hollow 104. For example, a fluid may be directed into the hollow
104 for cooling purposes. For another example, a fluid may be
directed into the hollow 104 to form another portion or layer of
the product 100. For instance, a fluid such as a pure or mixed
material may be used to partially or completely fill the hollow
104. Examples of pure or mixed materials include, but are not
limited to, plastics, polymers, foamed plastics, plastic
compositions, cellulosic-filled plastic compositions,
inorganic-filled plastic compositions, metals, metallic
compositions, alloys, mixtures including any of the aforementioned
materials, and other similar, conventional, or suitable materials.
The fluid may be similar or dissimilar to the material used to form
the exterior surface 102. For instance, the fluid and the material
used to form the exterior surface 102 may consist of the same
ingredients, but in different amounts. Alternatively, the fluid and
the material used to form the exterior surface 102 may consist of
at least one different ingredient. Some examples may be useful to
illustrate this point. One example of a product that may benefit
from the present invention has a foamed or unfoamed plastic layer
that is bonded to another foamed or unfoamed plastic layer. Another
example of a product that may benefit from the present invention
has a foamed or unfoamed plastic composite layer that is bonded to
another foamed or unfoamed plastic composite layer. Still another
example of a product that may be benefit from the present invention
has a foamed or unfoamed plastic composite layer that is bonded to
a foamed or unfoamed plastic layer. Of course, many other
embodiments are possible and within the scope of the present
invention.
[0026] Regardless of the type of fluid, the fluid may be directed
into the hollow 104 via an in-line system or a system that is not
in-line. In one embodiment, the present invention may be used to
provide improved cooling of a product. In another embodiment in
which a fluid forms a layer or portion of a product, the present
invention may be used to reduce the weight and/or material cost of
a product or to improve the physical characteristics of a product.
For example, a foamed plastic may be used to form a layer or
portion (e.g., a core layer) of a product that would otherwise be
entirely formed of an unfoamed plastic. Another possible benefit is
that the fluid (such as a fluid that forms a core layer) may help
to maintain the integrity of a profile as it is processed through a
sizing system. In addition, an in-line system may be more time and
cost efficient.
[0027] FIG. 2 shows one example of an extrusion die 200 adapted
with the present invention. The extrusion die 200 defines the cross
section of the extrudate by the shape of the profile form/flow
channel 206. Hollows in the cross section of the extrudate may be
formed with a standing core 202. The standing core 202 is fitted
with a spout or nozzle 204. The nozzle 204 may be adapted to
connect with a source of the cooling fluid (not shown).
Alternatively, the nozzle 204 may be adapted to connect with a
source of a fluid for forming a layer or portion of the resulting
product. The nozzle 204 may be oriented to spray or otherwise
release the fluid into the hollow formed in the extrudate cross
section by the standing core 202. The nozzle 204 may be recessed
from, even with, or extend away from the face of the die 200. In an
embodiment in which the nozzle 204 extends away from the face of
the die 200, the length of the extension may be any desired
distance. The extension may also be referred to as a dispensing
wand.
[0028] FIG. 3 shows one example of a system 300 that may utilize
the present invention. The system 300 includes an extruder 302 and
an extruder 304. In this example, a crosshead die 306 puts a cap
layer from the extruder 304 on the material extruded by the
extruder 302. A container 308 may be used to hold a cooling fluid
of the present invention. The fluid is used to cool the extruded
product or article 312 after it exits the die 306. In this
embodiment, a valve is used to control the release of gas, e.g.,
vapor, from the fluid. A hose, conduit, tube, or any other suitable
transfer device 310 may be used to direct the gas from the
container 308 to the desired location for cooling the extruded
product 312. The transfer device 310 may be formed by one integral
component or a plurality of interconnected components. For
instance, a portion of the transfer device 310 may be a passage
through the die 306. In this example, the transfer device 310
extends through the die 306 so that the gas is released in the
hollow of the extruded product 312 after it exits the die 306. In
this manner, the present invention can provide efficient and
thorough cooling of the extruded product 312. Moreover, the
extruded product 312 may be further introduced into a liquid bath
314, a spray mist chamber 316, and/or any other desired cooling
system to achieve additional cooling of the extruded product 312 if
desired. Examples of the liquid bath 314 and the spray mist chamber
316 are provided in U.S. Pat. No. 5,827,462.
[0029] Depending on the type of cooling fluid and the desired
expulsion rate of the cooling fluid, the container 308 may be
pressurized. The container 308 may be connected to a compressor,
e.g., an air compressor or any other similar, suitable, or
conventional compressing device, in order to maintain the desired
pressure in the container 308. Additionally, the container 308 may
be in fluid communication with a blower or a pump to obtain the
desired expulsion rate of the cooling fluid from the container 308.
A blower in fluid communication with the container 308 may also be
utilized to accelerate the cooling fluid to a desired velocity
after it has been expelled.
[0030] FIG. 4 is a cross section view along the line A-A of FIG. 3.
The extruded product 312 includes a cap layer 404. The transfer
device 310 may extend through the die 306 to a nozzle 406 that
releases gas from the cooling fluid into a hollow of the extruded
product 312. In this instance, gas vapor 402 permeates through the
hollow of the extruded product 312, thereby providing much improved
cooling of the extruded product 312. In fact, the inventors have
surprisingly discovered that using the present invention to inject
the cooling fluid into a hollow portion of a product may be
sufficient to thoroughly cool the entire product, i.e., the inside
and the outside of the product. As a result, the present invention
may eliminate the need to provide another cooling system to cool
the outer surface of the product.
[0031] It should be recognized that FIGS. 3 and 4 are merely one
example of a manufacturing system that may utilize the present
invention. As noted above, the present invention may be used in any
manufacturing system in which the processed material needs to be
cooled to a desired level. For example, the present invention may
be used in an extrusion system consisting of a single extruder that
is in-line with a die. Also, the present invention may be used to
cool any type of material including, but not limited to, injection
molded materials and compression molded materials.
[0032] In addition, it should be recognized that the system 300
shown in FIG. 3 may be adapted for use with another fluid that may
form a layer or portion of the resulting product. For example,
another extruder may be in fluid communication with the die 306 for
adding another layer or portion of the resulting product. The
extruder may be connected to the die 306 in a manner similar to
extruder 302 and extruder 304. If desired, the extruder may be
substituted for the container 308 and the transfer device 310. For
instance, with reference to FIG. 4, a fluid for forming a core
layer (instead of a cooling fluid) may be dispensed from the nozzle
406 into the hollow. However, it should be recognized that this
embodiment of the present invention may also be used in combination
with the cooling embodiment of the present invention. For example,
the fluid may form a layer or portion of the product other than a
core layer, or the fluid may not completely fill a hollow portion
of the product.
[0033] In addition, it should be recognized that the cooling fluid
of the present invention may be expelled elsewhere relative to the
manufactured product (i.e., other than in a hollow portion of the
product). For example, FIG. 5 shows an embodiment in which the gas
vapor 500 is dispersed by the transfer device 502 onto the exterior
of the product 504. The present invention also includes dispersing
multiple streams of the cooling fluid onto the same or different
portions of the manufactured product. For instance, flows of the
cooling fluid may be simultaneously dispersed onto the exterior and
interior surfaces of the manufactured product.
[0034] Turning to FIG. 6, this Figure shows a sectioned schematic
of an extruder line 600 used in accordance with the practice of one
embodiment of the present invention. FIG. 6 shows an extruder line
600 which includes co-extrusion apparatus 602. Co-extrusion
apparatus 602 includes insulated transport tube 604 that is adapted
to carry cooling fluid 606. Alternatively, the transport tube 604
may be adapted to carry a fluid for forming a layer or portion of
the product. The cooling fluid 606 may be gas that may be delivered
from a supply of cryogenic fluid. Co-extrusion apparatus 602 also
includes a cross head extruder 608 which is adapted to prepare the
thermoplastic material 610 for extrusion through a die which may
form a hollow, rectangular profile and urges it along longitudinal
direction 612. Further layers of thermoplastic material such as
layer 614 may be added through the use of additional extruders such
as extruder 616. Such additional layers of thermoplastic material
may include layers of material with specific characteristics for
exterior use, such as fluoropolymers and PVC having greater or
lesser durability and resistance to changes in aesthetic appearance
resulting from exposure to weather and environmental/atmospheric
conditions, as dictated by the desired end user. The thermoplastic
material 610 is formed by the forming die 618 into the desired
final shape, such as a rectangular cross-section. The cooling fluid
606 permeates through the hollow space created in thermoplastic
material 610. The cooling fluid 606 may be at a significantly lower
temperature than the surrounding thermoplastic material 610. The
cooling fluid 606 cools the thermoplastic material 610, assisting
the thermoplastic material to "skin" or solidify.
[0035] FIGS. 7 through 9 show a cross sectional view of one example
of a die 700 that is configured to be in-line with an extruder.
Extruded material flows through the die in the direction indicated
by arrow 702. In this example, the resultant extrudate 704 defines
three hollow portions that are separated by webs 706 and 708. A
fluid enters the die 700 through passages 710. The fluid entering
through passages 710 may be a cooling fluid or a fluid for
partially or completely filling the hollow portions of the
extrudate 704. In some embodiments, it should be recognized that a
tube, conduit, or any other type of transfer device may extend
through the passages 710 for directing the flow of the fluid
through the passages 710. The fluid exits the die 700 through
passages 710 in the direction indicated by arrows 712. In such an
embodiment, the passages 710 intersect the path of flow of the
extruded material that forms the extrudate 704. In other words, the
passages 710 intersect the flow channel in the die 700.
[0036] The die 700 may be heated to a sufficient level to
facilitate extrusion and limit premature curing of the extrudate in
the die 700. In this example of an in-line system, the passages 710
actually extend through the die 700, intersecting the path of flow
of the extruded material that forms extrudate 704. In some
embodiments, it may be preferable to limit cooling of the die 700
by a cooling fluid in the passages 710. In other embodiments, a
fluid in the passages 710 that is used fill the hollow portions may
be processed more effectively at a different temperature (e.g., a
higher or lower temperature) than the material used to form the
extrudate 704. Accordingly, the passages 710 may be insulated by a
suitable material. For example, the passages 710 may be lined with
ceramic insulation, putty ceramics, or any other similar, suitable,
or conventional insulating material in order to limit undesired
heat transfer by the die 700. In fact, it should be recognized that
the transfer device for the fluid in any type of embodiment may be
insulated in order to limit undesired cooling or heating of
surrounding items.
[0037] As best seen in the example of FIG. 9, the passages 710 may
be substantially surrounded by die material 714 even where the
passages 710 intersect the path of flow of the extruded material
that forms extrudate 704. In this manner, direct contact in the die
700 between the extruded material that forms extrudate 704 and the
passages 710 may be avoided, if desired. The die material 714
surrounding the passages 710 may be heated to facilitate the
extrusion process. Also, air gaps may be provided between the die
material 714 and the passages 710 for additional insulation.
[0038] Any desired cooling fluid may be used in the present
invention. In one exemplary embodiment, the cooling fluid, e.g.,
gas or liquid, may have a temperature below about 80 degrees
Fahrenheit, more preferably below about 68 degrees Fahrenheit,
still more preferably below about 32 degrees Fahrenheit, even more
preferably below about minus 100 degrees Fahrenheit. On the other
hand, the temperature may be above about minus 325 degrees
Fahrenheit, more preferably above about minus 300 degrees
Fahrenheit, still more preferably above about minus 275 degrees
Fahrenheit, even more preferably above about minus 250 degrees
Fahrenheit. However, in some embodiments of the present invention,
the cooling fluid may be above about 80 degrees Fahrenheit or below
about minus 325 degrees Fahrenheit. Examples of the cooling fluid
are air and water. Another example of the cooling fluid is gas or
vapor that is produced from a cryogenic fluid. For instance, a
cryogenic fluid may have a temperature below about minus 250
degrees Fahrenheit. Examples of cryogenic fluids include, but are
not limited to, liquid oxygen, liquid nitrogen, liquid neon, liquid
hydrogen, liquid helium, and other similar, suitable, or
conventional cryogenic fluids.
[0039] In addition to the temperature, the velocity of the cooling
fluid may also impact its effectiveness. By selecting a suitable
velocity and temperature of the cooling fluid, the inventors have
discovered that an entire product can be thoroughly cooled just by
injecting the cooling fluid into a hollow portion of the product.
The velocity of the cooling fluid may be greater than about 10
miles per hour, more preferably greater than about 40 miles per
hour, and it may be less than about 100 miles per hour, more
preferably less than about 50 miles per hour. However, it should be
recognized that the velocity of the cooling fluid may be less than
about 10 miles per hour or greater than about 100 miles per hour in
some embodiments.
[0040] The efficiency and effectiveness of the present invention
may be further increased by diverting the flow of the fluid (e.g.,
a cooling fluid or a fluid that forms a layer or portion of the
resulting product) toward the surface of the extruded product as it
exits the die. By concentrating a cooling fluid on a surface of the
extrudate, the desired amount of cooling may occur more quickly
resulting in the use of less cooling fluid as compared to
non-diversion methods. Moreover, the increased cooling efficiency
enables the use of warmer cooling fluids and a reduction in the
velocity of the cooling fluid as compared to non-diversion methods.
For example, this embodiment of the present invention may be
particularly useful if it is desired to use a cooling fluid that is
warmer than about 80 degrees Fahrenheit. However, it should be
recognized that, in many embodiments, it may be desirable to use a
cooling fluid below about 80 degrees Fahrenheit for optimal cooling
efficiency. On the other hand, in the case of a fluid that is used
to form a layer or portion of the resulting product, the diversion
of the fluid toward a surface of the extruded product as it exits
the die may facilitate the formation of the desired end
product.
[0041] FIG. 10 shows one example of a die that is adapted to divert
a fluid toward a surface of an extruded project. The die 800 of
this embodiment may include any of the optional or preferred
features of the die 700 shown in FIGS. 7 through 9. The fluid may
enter the die 800 through a passage 810. A baffle 820 is in fluid
communication with the passage 810 such that it receives the fluid.
The baffle 820 is adapted to then divert the flow of the fluid such
that it is directed to a desired surface of the extrudate. By
directing a cooling fluid toward a surface of the extrudate, the
baffle 820 may also create a more turbulent flow of the cooling
fluid (as compared to a straight line flow that is not directed
toward a surface of the extrudate) which further enhances the
efficiency of the cooling process. The baffle 820 may be any device
or structure that is suitable for diverting the flow of the fluid
to the desired location (e.g., an interior or exterior surface of a
product). In this particular example, the baffle 820 is adapted to
divert the fluid in the direction of arrows 830 toward an interior
surface of a hollow portion of the extrudate. For this purpose, the
baffle 820 includes an inner conical portion 840 that forces the
fluid in the direction of arrows 830.
[0042] FIG. 10 shows one example of a design of a baffle 820. It
should be recognized that the design of a baffle of the present
invention may vary so as to divert the fluid in the desired
direction. Of course, the desired direction will vary according to
the type of product being extruded and the location of the baffle
relative to the extruded product.
[0043] The baffle 820 may be placed in fluid communication with the
passage 810 in any suitable manner. In the example of FIG. 10, the
baffle 820 is secured to an end portion of a conduit 850 that
extends through the passage 810. The baffle 820 may be secured to
the end portion of the conduit 850 in any desired manner. For
example, the baffle 820 may be threaded, i.e., screwed, onto the
end portion of the conduit 850. For other examples, the baffle 820
may be secured to the conduit 850 using other mechanical means
(e.g., screws, pins, and other types of mechanical fastening
devices) and/or adhesives. As previously noted, the conduit 850 may
be insulated. The baffle 820 may also be insulated, if desired. The
baffle 820 is offset from the heated portion 860 of the die 800 in
this particular example. Optionally, there may be an insulated
layer 870 on an exit end of the die 800. The insulated layer 870
may be useful to prevent a cooling fluid from cooling the heated
portion 860 of the die 800.
[0044] FIG. 11 shows another example of a die which may include any
of the optional or preferred features of the other embodiments of
the present invention. In this embodiment, the die 900 includes a
passage 910 that is in fluid communication with the baffle 920. The
baffle 920 is not offset from the heated portion 930 of the die 900
in this example. In order to limit undesired heat transfer from or
to the heated portion 930, it may be preferred to use an insulated
baffle 920 or otherwise provide a layer of insulation between the
baffle 920 and the heated portion 930. As in the previous example,
the baffle 920 may be connected to a conduit 940 that lines that
passage 910. It should also be recognized that the baffle 920 may
be placed in fluid communication with the passage 910 in any other
suitable manner. For example, the baffle 920 may have a threaded
connection with the heated portion 930. In other examples, the
baffle 920 may be connected to the heated portion 930 using other
mechanical means (e.g., screws, pins, and other types of mechanical
fastening devices) and/or adhesives. As in the previous example, an
exit end of the die 900 may include a layer of insulation 950.
[0045] The inventors have also made the surprising and significant
discovery that the efficiency and efficacy of the manufacturing
process may be improved by placing a liquid cryogenic fluid in
direct contact with the material to be cooled. As a result, the
rate of output may be increased, thereby decreasing the unit cost
of the manufactured product. In addition, the inventors have
discovered that the more rapid cooling providing by direct contact
with a liquid cryogenic fluid may improve the structural
characteristics of the manufactured product, especially in the case
of foam products. In particular, the rapid removal of the heat may
help to maintain the desired foam structure.
[0046] FIG. 12 shows one example of a system that enables direct
contact of the material with the liquid cryogenic fluid. System 120
may include a die 122 which is adapted to receive material from a
piece of processing equipment, e.g., an extruder. Optionally, a
sizer 124 may be in fluid communication with the die 122. One
example of a sizer 124 is a vacuum sizer. After the material exits
the die 122 and, optionally, sizer 124, the material enters a bath
126 of liquid cryogenic fluid. In the bath 126, the material comes
into direct contact with the liquid cryogenic fluid. The duration
of the contact may vary according to the particular material,
manufacturing process, and degree of cooling that is desired.
Nevertheless, it should be recognized that just a brief period of
contact (e.g., mere seconds) may provide a significant of degree of
heat removal. Depending on the material, overexposure to the liquid
cryogenic fluid may eventually have a negative impact on the
manufactured product.
[0047] The features and physical dimensions of the bath 126 may be
selected taking into consideration the minimum length of material
needed for a specific application, the line speed, the desired
amount of heat removal, and other factors relevant to the safety,
maintenance, and performance of the system 120. In one exemplary
embodiment, the bath 126 may include at least one sizing component
(i.e., sizer or sizing box) 128. A sizing component 128 may be
partially or totally submersed in the liquid cryogenic fluid during
operation of the system 120. The bath 126 may also be equipped with
suitable safety and maintenance features. For example, the bath 126
may have a cover 130 to facilitate maintenance of the bath 126.
Additionally, the bath 126 may be dual-walled and insulated, and
the bath 126 may include a suitable exhaust system.
[0048] The bath 126 may include a level of liquid cryogenic fluid
sufficient to partially or totally submerse the material to be
cooled. For instance, the bath 126 may include a level of liquid
cryogenic fluid sufficient to directly contact one portion of the
material to be cooled while another portion does not come into
contact with the liquid cryogenic fluid. Moreover, it should be
recognized that the liquid cryogenic fluid may be transferred into
and out of the bath 126 based on the operational status of the
system 120. For example, the system 120 may also include a pump 132
and a holding tank 134. The pump 132 may transfer the liquid
cryogenic fluid to the bath 126 from the tank 134 approximately
when the particular manufacturing process (e.g., extrusion) is
initiated or at any other suitable time such that there is a
desired amount of liquid cryogenic fluid in the bath 126.
Furthermore, the pump 132 may transfer the liquid cryogenic fluid
back to the tank 134 after the manufacturing process (e.g.,
extrusion) is complete or at any other suitable time. The tank 134
may be equipped with any suitable safety and maintenance features
including, but not limited to, those included on the bath 126.
Additionally, it should be recognized that a suitable safety
interlock system may be included to prohibit undesired transfer of
the liquid cryogenic fluid between the bath 126 and the tank
134.
[0049] At least one additional cooling system 136 may be included
subsequent to the bath 126. Examples of a cooling system 136
include, but are not limited to, a water bath, a spray mist, air
flow, another cooling system as described herein, or any other
conventional or new cooling system. Additionally, it should be
noted that a cooling system 136 (or additional manufacturing
equipment) may be included prior to the bath 126 without departing
from the scope of the present invention.
[0050] As mentioned above, many significant advantages may be
achieved by placing the material to be cooled in direct contact
with liquid cryogenic fluid. In addition to cooling extruded
products, the present invention may be used to cool products made
by any other methods including, but not limited to, compression
molded products and injection molded products. Regardless of the
manufacturing method, the output rate may increased and the unit
cost may be decreased due to the dramatic improvement in cooling
efficiency. Also, the capital cost of an exemplary system of the
present invention may be reduced as compared to conventional gas
cooling systems which require some gas velocity. In addition, the
increased cooling efficiency may allow shorter manufacturing lines,
thereby further reducing the manufacturing cost.
[0051] A variety of products may benefit from the present
invention. Examples of products that may benefit the present
invention include, but are not limited to, fence components,
furniture components, cabinet components, storage device
components, lawn edging components, flower box components, floor
components, baseboards, roof components, wall covering components,
siding components, basement floor components, basement wall
covering components, interior and exterior decorative house molding
components, crown molding components, chair rail components,
picture frame components, deck components, railing components,
window molding components, window components, window frames,
lineals, door components, door frames, door moldings, boards, and
other suitable indoor and outdoor items.
[0052] Any embodiment of the present invention may include any of
the optional or preferred features of the other embodiments of the
present invention. The exemplary embodiments herein disclosed are
not intended to be exhaustive or to unnecessarily limit the scope
of the invention. The exemplary embodiments were chosen and
described in order to explain the principles of the present
invention so that others skilled in the art may practice the
invention. Having shown and described exemplary embodiments of the
present invention, those skilled in the art will realize that many
variations and modifications may be made to affect the described
invention. Many of those variations and modifications will provide
the same result and fall within the spirit of the claimed
invention. It is the intention, therefore, to limit the invention
only as indicated by the scope of the claims.
* * * * *