U.S. patent application number 10/456248 was filed with the patent office on 2003-11-13 for twin screw extruder with conical non-parallel converging screws.
Invention is credited to Hauck, Bobbie W., Wenger, Lavon G..
Application Number | 20030210605 10/456248 |
Document ID | / |
Family ID | 26748671 |
Filed Date | 2003-11-13 |
United States Patent
Application |
20030210605 |
Kind Code |
A1 |
Hauck, Bobbie W. ; et
al. |
November 13, 2003 |
Twin screw extruder with conical non-parallel converging screws
Abstract
An improved twin screw extruder device (14) is provided which is
capable of producing a wide variety of high quality extrudates
having greatly varying final properties, without the need for
extensive machine modifications. The extruder (14) includes a
barrel (16) together with a co-rotating twin screw assembly (22).
The assembly (22) is made up of a pair of screws (50, 52) having
central, tapered shafts (54, 56) equipped with outwardly extending
helical flighting (58, 60); the screws (50, 52) are non-parallel
and are positioned so that the flighting (58, 60) thereof is
intercalated along the length of the screws (50, 52). The flighting
is of specialized configuration and tapers along the length of the
screws (50, 52) preferably at an angle of taper different than that
of the shafts (54, 56); moreover, the width of the outer flighting
surfaces (70, 72) increases along the length of the shafts (54,
56). This screw geometry defines a series of alternating upper and
lower close-clearance high-pressure nip areas (78) defined by the
flighting (58, 60) which serves to propel an extrudable mixture
forwardly towards the outlet end (20) of the barrel (16). However,
passageways (80) and kneading zones (82) are also defined between
the screws (50, 52), which assures full mixing, shearing and
cooking of the material. The extruder device (14) is capable of
producing high density sinking aquatic feeds as well as expanded,
low density products merely by changing the rotational speed of the
screws (50, 52) together with appropriate temperature control. In
another embodiment, a fluid extraction extruder (138) is provided
having a specialized extruder head (140) including an outer shell
(144) and an inner, elongated, slotted sleeve (152).
Inventors: |
Hauck, Bobbie W.; (Sabetha,
KS) ; Wenger, Lavon G.; (Sabetha, KS) |
Correspondence
Address: |
HOVEY, WILLIAMS, TIMMONS & COLLINS
Suite 400
2405 Grand
Kansas City
MO
64108
US
|
Family ID: |
26748671 |
Appl. No.: |
10/456248 |
Filed: |
June 5, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10456248 |
Jun 5, 2003 |
|
|
|
10068181 |
Feb 5, 2002 |
|
|
|
6609819 |
|
|
|
|
10068181 |
Feb 5, 2002 |
|
|
|
09912144 |
Jul 24, 2001 |
|
|
|
Current U.S.
Class: |
366/87 ; 366/85;
366/89 |
Current CPC
Class: |
B29C 48/525 20190201;
B29B 7/484 20130101; B29C 48/05 20190201; B29B 7/582 20130101; B29B
7/489 20130101; B30B 9/16 20130101; A23P 30/20 20160801; B29C
48/252 20190201; B29C 48/395 20190201; B29B 7/801 20130101; B30B
9/26 20130101; B29B 7/488 20130101; B29C 48/402 20190201 |
Class at
Publication: |
366/87 ; 366/85;
366/89 |
International
Class: |
B29B 007/48 |
Claims
We claim:
1. An extruder head comprising an elongated body having an outer
shell and an inner extraction sleeve disposed within said shell,
said sleeve having an inner surface defining an internal, elongated
passageway adapted to receive at least one extrusion screw
component and an outer surface, with a plurality of slots formed in
the sleeve and extending from said inner surface to said outer
surface, said slots configured to permit an extracted fluid to pass
therethrough for collection in said shell.
2. The extruder head of claim 1, wherein said shell includes an
extracted fluid outlet.
3. The extruder head of claim 1, at least certain of said slots
being tapered and having a width adjacent said inner surface which
is less than the width thereof adjacent said outer surface.
4. The extruder head of claim 1, said passageway being tapered
along the length thereof.
5. The extruder head of claim 1, said passageway being of generally
FIG. 8 configuration to accommodate side-by-side extrusion
screws.
6. The extruder head of claim 1, said sleeve formed of a plurality
of interconnected, elongated bars.
7. An extruder comprising an elongated barrel presenting a material
inlet and a material outlet; and at least one elongated axially
rotatable, helically flighted screw located within said barrel and
operable for moving material from said inlet to said outlet, said
barrel including a section having an outer shell and an inner
extraction sleeve disposed within said shell, said sleeve having an
inner surface defining an internal, elongated passageway receiving
a portion of said screw and an outer surface, with a plurality of
slots formed in the sleeve and extending from said inner surface to
said outer surface, said slots configured to permit an extracted
fluid to pass there-through for collection in said shell, said at
least one screw and said sleeve cooperatively configured for
extraction of fluid from said material during passage through said
barrel section, and collection of said fluid within said shell
8. The extruder of claim 7, wherein said shell includes an
extracted fluid outlet.
9. The extruder of claim 7, at least certain of said slots being
tapered and having a width adjacent said inner surface which is
less than the width thereof adjacent said outer surface.
10. The extruder of claim 7, said passageway being tapered along
the length thereof.
11. The extruder of claim 7, said passageway being of generally
FIG. 8 configuration to accommodate side-by-side extrusion
screws.
12. The extruder of claim 7, said sleeve formed of a plurality of
interconnected, elongated bars.
13. The extruder of claim 7, said section being located adjacent
said outlet.
Description
RELATED APPLICATION
[0001] This is a divisional of Ser. No. 10/068,181 filed Feb. 5,
2002 which is a continuation-in-part of application Ser. No.
09/912,144 filed Jul. 24, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is broadly concerned with improved
twin screw extrusion devices of a highly versatile nature which can
be used for the production of a wide variety of end products of
varying densities, cook values and expansion ratios, without the
need for extensive machine modifications. The extruders of the
invention include a twin screw assembly having non-parallel,
tapered conical screws with the flighting of the screws
intercalated along the length of the extruder barrel to define
close-clearance, preferably constant dimension, alternating upper
and lower nip areas and trailing kneading zones and reverse flow
passageways; the nip areas create high pressure zones within the
barrel which propel material forwardly, while the material is
kneaded and allowed to reverse flow in the zones and passageways.
In other embodiments, an infinitely variable die assembly including
a shiftable stem movable between a waste disposal position and a
variety of extrusion positions. A specialized fluid extraction
final extruder head is also provided, which allows oils or other
fluids to be efficiently extracted, particularly with the aid of a
supercritical extractant such as carbon dioxide.
[0004] 2. Description of the Prior Art
[0005] Extrusion cooking devices have long been used in the
manufacture of a wide variety of edible and other products such as
human and animal feeds. Generally speaking, these types of
extruders include an elongated barrel together with one or more
internal, helically flighted, axially rotatable extrusion screws
therein. The outlet of the extruder barrel is equipped with an
apertured extrusion die. In use, a material to be processed is
passed into and through the extruder barrel and is subjected to
increasing levels of temperature, pressure and shear. As the
material emerges from the extruder die, it is fully cooked and
shaped and may typically be subdivided using a rotating knife
assembly. Conventional extruders of this type are shown in U.S.
Pat. Nos. 4,763,569, 4,118,164 and 3,117,006.
[0006] Most conventional modern-day extrusion cookers are made up
of a series of interconnected tubular barrel heads or sections with
the internal flighted screw(s) also being sectionalized and mounted
on powered, rotatable shaft(s). In order to achieve the desired
level of cook, it has been thought necessary to provide relatively
long barrels and associated screws. Thus, many high-output pet food
machines may have five to eight barrel sections and have a length
of from about 10 to 20 times the screw diameter. As can be
appreciated, such long extruders are expensive and moreover present
problems associated with properly supporting the extrusion screw(s)
within the barrel. However, prior attempts at using relatively
short extruders have not met with success, and have been plagued
with problems of insufficient cook and/or relatively low
yields.
[0007] U.S. Pat. Nos. 5,939,124 and 5,694,833 describe short
length, high speed cooking extruders which address the problem of
excessively long barrel and screw lengths, and thus represent a
distinct advance in the art. These extruders, sold by Wenger
Manufacturing, Inc. as U P/C extruders, have achieved considerable
commercial success.
[0008] However, most prior extruders must be designed with screw
and barrel section configurations which are specific to a desired
product. That is, the configuration used for the production of high
density aquatic feeds is generally significantly different than
that which would be necessary to produce medium density pet foods
or low density feeds. As a consequence, the extruder must be broken
down and reconfigured if it is desired to change the product to be
produced. Moreover, in some cases an extruder designed for one type
of product simply cannot be reconfigured successfully to
efficiently produce a significantly different type of product.
[0009] Oils such as soybean oil are conventionally extracted from
soybeans by mechanical extraction techniques, solvent extraction
and/or supercritical fluid technologies. For large production
operations, mechanical extractors are inefficient, and the
extracted oil requires considerable refinement. On the other hand,
supercritical fluid (e.g., CO.sub.2) extraction devices are too
expensive and complex for existing oil plants. Solvent extraction
using hexane or other solvents presents environmental problems
associated with disposal of the solvent.
[0010] There is accordingly a need in the art for improved extruder
equipment of great flexibility and versatility and which can be
used to yield dissimilar products without extensive reconfiguration
or reworking of the internal extruder components; moreover,
improved equipment for the extraction of high quality oils and the
like while avoiding the problems of solvent extraction would be an
important breakthrough.
SUMMARY OF THE INVENTION
[0011] The present invention overcomes the problems outlined above
and provides a twin screw extruder having an elongated barrel with
a material inlet and a material outlet usually equipped with a
restricted orifice die, together with specially configured
extrusion screws within the barrel. Each screw includes an
elongated central shaft having a shaft rear end and a shaft front
end with outwardly extending helical flighting provided along the
length of the central shaft to provide a flighting rear end, a
flighting front end and an outer flighting surface spaced from the
central shaft. The central shaft may be of constant diameter but
preferably is progressively tapered through a first taper angle
along the length thereof from rear to front; similarly, the
flighting may be of constant depth but is preferably tapered from
rear to front through a second taper angle. Optimally but not
necessarily the shaft and flighting taper angles are different,
with the latter being greater than the former. Also, the width of
the outer flighting surface maybe constant from rear to front but
advantageously the width changes progressively along the length of
the flighting from rear to front; again most preferably, the width
of the flighting increases from rear to front so that the width of
the outer flighting surface adjacent the front end is greater than
the width of the outer flighting surface adjacent the flighting
rear end.
[0012] The twin screws are positioned in juxtaposition with the
central axes of the shafts converging towards each other so that
these axes define an included angle. Further, the flighting of the
shafts is intercalated, preferably along the entire flighting
length. In this fashion, the screws cooperatively define a series
of close-clearance, alternating upper and lower nip areas along the
length of the screw set. Preferably, the flighting clearance at the
respective nip areas is substantially constant along the full
length of the screw set, although more generally the nip clearances
may increase or decrease along the length of the screw set. The
design of the screw set to present the close-clearance nip areas
creates a series of high pressure zones within the extruder which
serve to positively propel the material being extruded forwardly in
a "pulsing" fashion.
[0013] It has been found that the extruder design affords a high
degree of operational flexibility, so that the extruder may be used
to produce a variety of products simply by changing the rotational
speed of the screw assembly and possibly other processing condition
changes (e.g., temperature and die configuration). It has been
observed that changes in preconditioning perimeters have a more
pronounced effect on the end product, than is common with
conventional extrusion equipment. Accordingly, the simple expedient
of changing steam and/or water input to the preconditioner can in
and of itself significantly impact the properties of the final
extrudate.
[0014] In another aspect of the invention, an extruder design for
extraction of fluids such as oil from oil seed materials is
provided. Such an extruder preferably although not necessarily
includes the features described above, but includes an extruder
head section including an outer shell equipped with a fluid outlet,
together with an internal, elongated, slotted sleeve which receives
a portion of the extruder screw(s). The sleeve is preferably
constructed from a series of elongated bar members which are welded
or otherwise affixed together to form a tubular sleeve, with
passageways between adjacent bars. The passageways are preferably
tapered and present a smaller opening at the interior of the
sleeve, as compared with the exterior thereof. In use, an oil seed
or other material is passed through the extruder so that in the
head section the fluid to be recovered is pressed or extruded
through the sleeve passageways. Fluid extraction is materially
enhanced by injection of a supercritical fluid such as carbon
dioxide or propane into the extruder head section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a partially schematic side elevational view of an
extrusion system including the improved extruder device in
accordance with the invention;
[0016] FIG. 2 is a perspective view of the preferred twin extrusion
screw set used in the extruder device;
[0017] FIG. 3 is a fragmentary horizontal sectional view of the
preferred twin screw extruder;
[0018] FIG. 4 is a vertical sectional view of the twin screw
extruder;
[0019] FIG. 5 is a fragmentary, greatly enlarged top view of
portions of the twin screw assembly, illustrating in detail the
intercalation of the screw flighting and the close-clearance nip
zones between the flighting;
[0020] FIG. 6 is a horizontal sectional view of the twin screw
portions illustrated in FIG. 5;
[0021] FIG. 7 is a fragmentary vertical sectional view illustrating
an extruder in accordance with the invention equipped with a
variable output die assembly, the latter in a full-open
condition;
[0022] FIG. 8 is a fragmentary sectional view taken along line 8-8
of FIG. 7;
[0023] FIG. 9 is a fragmentary vertical sectional view similar to
that of FIG. 7 but depicting the die assembly in the diverter
condition thereof;
[0024] FIG. 10 is a sectional view taken along line 10-10 of FIG.
7;
[0025] FIG. 11 is a fragmentary vertical sectional view of an
extruder in accordance with the invention, equipped with a final
head designed for extraction of oil from oil seeds;
[0026] FIG. 12 is a vertical sectional view taken along line 12-12
of FIG. 11;
[0027] FIG. 13 is a perspective view of one of the bar elements
used in the fabrication of the final head illustrated in FIGS. 11
and 12; and
[0028] FIG. 14 is a perspective view of a pair of adjacent bar
elements, depicting an oil extraction slot between the bar
elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] Embodiment of FIGS. 1-6
[0030] Turning now to the drawings, FIG. 1 illustrates an extrusion
system 10 made up of a preconditioner 12 as well as a twin screw
extruder device 14. The device 14 broadly includes a sectionalized
barrel 16 presenting an inlet 18 and an outlet 20, with a
specialized twin screw assembly 22 within the barrel 16; the
assembly 22 is coupled via a gear box drive 24 to motor 26.
[0031] The preconditioner 12 is designed to initially moisturize
and partially precook dry ingredients prior to passage thereof as a
dough or the like into the inlet 18 of device 14. To this end, the
preconditioner 12 is typically in the form of an elongated chamber
equipped with rotatable internal paddles as well as injection ports
for water and/or steam. A variety of preconditioners maybe used in
the context of the invention. However, it is particularly preferred
to use Wenger DDC preconditioners of the type described in U.S.
Pat. No. 4,752,139, incorporated by reference herein.
[0032] The barrel 16 in the embodiment illustrated is made up of
three end-to-end interconnected tubular barrel heads 28, 30, 32,
each provided with an external jacket 34, 36, 38 to allow
circulation of cooling or heating media for temperature control of
the extruder device. It will be observed that the first head 28
includes the inlet 18, whereas the last head 32 is designed to
accept a die assembly 40. Each of the heads 28-32 also includes an
internal sleeve 42, 44 and 46 which cooperatively define a tapered,
continuous screw assembly-receiving opening 48 within the barrel.
This opening 48 has a generally "figure eight" shape in order to
accommodate the screw assembly 22. As illustrated, the opening 48
is widest at the rear end of head 28 and progressively and
uniformly tapers to the end of head 32.
[0033] The screw assembly 22 includes first and second elongated
screws 50, 52 which are in side-by-side relationship as best seen
in FIGS. 2 and 3. Each of the screws 50, 52 includes an elongated
central shaft 54, 56 as well as outwardly extending helical
flighting 58, 60. The shafts 54, 56 each have an outer surface
which is progressively and uniformly tapered through a first taper
angle from points 62, 64 proximal to the rear ends of the
corresponding shafts 54, 56, to forward points 66, 68 adjacent the
forward ends of the shafts. This taper angle varies from about
0.5-5.degree., and more preferably from about 1-2.2.degree.. The
present embodiment has a taper angle of 1.3424.degree..
[0034] The flighting 58, 60 (in the embodiment illustrated double
flights are used, but single or multiple flights are also a
possibility) extends essentially the full length of the shafts 52,
54 between points 62, 66 and 64, 68. Thus, the flighting 58, 60
proceeds from a rear end adjacent the point 62, 64 in a continuous
fashion to the forward point 66, 68. In addition, the flighting
presents an outer surface 70, 72 on each of the screws 50, 52,
having a width denoted by "W" in FIG. 6, as well as a flight depth
between the outer surface of the central shaft and the outer
flighting surface, denoted by "D" in FIG. 6. The geometry of the
flighting 58, 60 is such that the flight depth D progressively and
uniformly decreases as the flighting proceeds from the rear end to
the front end of the screws 50, 52. Consequently, the outer
surfaces 70, 72 of the flighting 58, 60 also taper from rear to
front in a progressive and uniform fashion. The second angle of
taper of the flighting depth and the outer flighting surfaces
ranges from 2-6.degree. and more preferably from about
2.5-4.degree.. The precise second angle of taper in the illustrated
embodiment is 3.304.degree..
[0035] Finally, the flighting 58, 60 is designed so that the width
"W" of the flighting outer surfaces 70, 72 increases in a
progressive and uniform fashion from the rear end of the screws to
the front ends thereof. This configuration is best illustrated in
FIGS. 3 and 4, where it will be seen that the width W is relatively
small at the rear ends of the screws 50, 52, but increases to a
wider width W at the forward ends of the screws. As indicated
previously however, the width W may be constant throughout the
length of the screws, or could narrow from the rearward ends to the
forward ends thereof. Accordingly, the ratio of the width at the
forward or input end of each screw to the width at the rearward or
output end ranges from about 0.5 to 5, and more preferably from
about 1 to 3.
[0036] The screws 50, 52 are oriented so that their respective
center axes 74, 76 (see FIG. 5) are at a converging angle relative
to each other, so that an included angle is defined by the center
axes. This included angle generally ranges from about 1-8.degree.,
more preferably from about 1.5-5.degree.. The included angle in the
illustrated embodiment is 2.3240.degree.. When the screws 50, 52
are oriented as described within barrel opening 48, the flighting
58, 60 of the respective screws 50, 52 is intercalated, i.e., each
of the flightings defines an imaginary frustum of a cone between
the rear and front ends of the corresponding screws, and the
flighting 58, 60 extends within the imaginary frustum of the
adjacent screw.
[0037] Attention is next directed to FIGS. 5 and 6 which depicts in
detail the intercalation of the flighting 58, 60. As shown, and by
virtue of the selection of appropriate first and second taper
angles and the included angle between the center axes 74, 76, the
flighting presents a plurality of close-clearance nip zones 78
along the length of the screw assembly 22. These nip areas present
a clearance between the flightings 58, 60 which is preferably
substantially constant along the length of the screw assembly 22.
More generally, if desired such nip clearances could increase or
decrease along the length of the assembly 22. In practice, the
clearance at the nip zones ranges from about 0.010-0.2 inches, and
more preferably from about 0.025-0.1 inches. The particular
illustrated embodiment exhibits an as-manufactured clearance at the
nip areas of 0.039 inch. In addition to the nip areas 78, it will
be observed that the assembly 22 also presents material backflow
passageways 80 and kneading zones 82 between the screws 50, 52.
These features are important for purposes to be described.
[0038] The gear box drive 24 is a device especially designed to
accommodate non-parallel shafts and broadly includes an adapter
housing 84 together with a pair of couplers 86 for connection to
the splined ends of the shafts 54, 56. The drive motor 26 is itself
entirely conventional, and is sized to drive the extruder device 14
at appropriate rotational speeds under the loads encountered.
[0039] In the operation of system 10, a variety of end products can
be produced having a multitude of final properties such as percent
expansion, density, percentage cook and other parameters. Broadly
speaking, it is preferred that the extrudable mixtures fed into and
through the system 10 include respective quantities of
protein-bearing and starch-bearing materials and also usually a
quantity of fat and added moisture. Typical grain ingredients used
in the extrudable mixtures are selected from the group consisting
of wheat, corn, oats, barley, rye, sorghum, soybean, rice and
mixtures thereof, while starches can be used from any grain, root
or tuber starch source. Also, additional ingredients such as
surfactants and inert fillers can form a part of the extrudable
mixtures. Most useful extrudable feed mixtures contain from about
30-75% by weight total protein, more preferably from about 40-65%
by weight total protein; total starch content of from 0-25% by
weight, more preferably from about 5-20% by weight; and a fat
content of from about 4-12% by weight, more preferably from about
6-10% by weight.
[0040] In the first step of a typical extrusion run, the extrudable
mixture is dry blended and fed into preconditioner 18. During
preconditioning, the mixture is further blended and steam and/or
water are added so as to at least partially precook the mixture.
While conditions within the preconditioner are variable, as a
general practice the mixture should be heated to a temperature of
from about 125-210.degree. F., more preferably from about
175-210.degree. F., in the preconditioner. The average residence
time in the preconditioner ranges from about 15-600 seconds, more
preferably from about 120-300 seconds.
[0041] After preconditioning, the extrudable mixture is passed into
and through the extruder device 14. The screw assembly 22 is
rotated so as to co-rotate the screws 50, 52, usually at a speed of
from about 200-1,200 rpm and more preferably from about 400-750
rpm. Pressures within the extruder are usually at a maximum just
adjacent the outlet die, and usually range from about 500-21,000
kPa, more preferably from about 1,000-10,500 kPa. Maximum
temperatures within the extruder normally range from about
150-550.degree. F., more preferably from about 160-300.degree. F.
Average residence time of the mixture within the extruder device is
from about 2-25 seconds, more preferably from about 4-15 seconds,
and most preferably from about 6-10 seconds.
[0042] Extrusion conditions are created within the device 14 so
that the product emerging from the extruder barrel usually has a
moisture content of from about 8-35% by weight wet basis, more
preferably from about 15-22% by weight wet basis. The moisture
content is derived from native water of the ingredients, moisture
added during preconditioning and/or any water injected into the
extruder barrel during processing. In terms of expansion, the level
of expansion can be from 0-75%, i.e., the diameter of the extrudate
may have essentially the same diameter as the die openings (which
would be 0% expansion), or may be enlarged to have a diameter of
1.75 times the diameter of the die openings (representing 75%
expansion). The products as extruded usually exhibit from about
70-90% starch gelatinization, which is a measure of the degree of
cook of the product; however, it is believed that the protein
content is not completely denatured in many of the products, but
this is dependent upon the particulars of the extrudable mixture
and the extrusion conditions. Bulk densities of the products
normally range from about 24-700 g/L, more usually from about
290-500 g/L. The products can also have a wide range of pellet
durability index (PDI) values usually on the order of from about
65-99, more preferably from about 80-97.
[0043] During passage of the extrudable mixture through the barrel
16, the screw assembly 22 acts on the mixture to create, together
with the endmost die 40, the desired product. The specific
configuration of the screws 52, 54 as described above generates
conditions not heretofore found with conventional twin screw
extruders. That is, as the mixture is advanced along the length of
the co-rotating screws 52, 54, it continually encounters the
alternately upper and lower close-clearance nip areas 78 which
generate relatively high localized pressures serving to push or
"pump" the material forwardly; at the same time, the product is
kneaded within the zones 82 as the screws rotate, and backflow of
material is allowed through the passageways 80. The result is an
intense mixing/shearing and cooking action within the barrel 16.
Furthermore, it has been found that a wide variety of products may
be produced using the equipment of the invention; simply by
changing the rotational speed of the screw assembly 22 and, as
necessary, temperature conditions within the barrel. For example,
relatively dense sinking aquatic feeds may be produced in good
yield with the machine configuration illustrated herein; however,
light density bird feeds can also be made on the very same
equipment, merely by changing the operational characteristics of
the machine. This degree of flexibility and versatility is
unprecedented in the extrusion art.
[0044] The following examples set forth a series of extrusion runs
for the production of several types of feeds, using the improved
twin screw extruder device of the invention. It is to be
understood, however, that these examples are provided by way of
illustration and nothing therein should be taken as a limitation
upon the overall scope of the invention.
EXAMPLE 1
[0045] In this example, an extruder in combination with a
preconditioner was employed in the manufacture of high quality
salmon feed at commercial production rates.
[0046] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular, the extruder configuration
used in Runs #1-7 was made up of the following components (where
all parts are identified with Wenger Mfg. Co. part numbers):
extruder model C.sup.2TX; extruder barrel-74002-424 (head No. 1);
two 74002-425 (heads Nos. 2 and 3); Head No. 1 was equipped with
sleeve 74002-421; Head No. 2 was equipped with sleeve 74002-422;
Head No. 3 was equipped with sleeve 74002-423. Final die--65534-003
NA; 53672-003 AD; 31950-397 IN; and 65422-015 NA. A rotating knife
assembly was positioned adjacent the outlet of the die for cutting
the extrudate into a convenient size. The knife assembly included
the following: 19462-015 (knife holder) and twelve knife blades
(19430-007).
[0047] The preconditioner used in these runs was a Wenger Model 54
DDC preconditioner in the 377 configuration with the left and right
shafts being equipped with 60 beaters each.
[0048] The aquatic feed recipes used in each run are set forth in
Table 1.
1TABLE 1 Run Run Run Run Run Run Run Ingredient #1 #2 #3 #4 #5 #6
#7 Fish Meal % wt 72.00 78.00 84.00 90.32 98.00 79.80 68.04 Wheat
Flour % wt 13.00 10.00 7.00 -- -- -- -- (from Wenger) Wheat Flour %
wt 13.00 10.00 7.00 7.53 -- 6.66 -- (from Lasi) Dicalcium Phosphate
% wt 1.00 1.00 1.00 1.08 1.00 0.94 1.63 Calcium Carbonate % wt 1.00
1.00 1.00 1.08 1.00 0.94 1.63 Soybean Meal -- -- -- -- -- 6.66 --
Soy Concentrate (from % wt -- -- -- -- -- 5.00 28.70 Central
Soya)
[0049] The following table sets forth the operating conditions for
the preconditioner and extruder devices in the seven runs.
2 TABLE 2 RUN #1 RUN #2 RUN #3 RUN #4 RUN #5 RUN #6 RUN #7 DRY
RECIPE INFORMATION: Dry Recipe Moisture % wb 10.31 9.28 9.37 9.71
8.86 7.96 7.81 Feed Screw Speed rpm 40 33 33 33 33 33 33 Dry Feed
Rate kg/hr 4800 4000 4000 4000 4000 4000 4000 PRECONDITIONING
INFORMATION: Preconditioner Speed rpm 250 -- -- 250 250 250 250
Steam Flow to Preconditioner kg/hr 236 262 290 286 262 262 262
Water Flow to Preconditioner kg/hr 216 239 239 239 239 239 239
Preconditioner Discharge Temp. .degree. F. 184 194 206 206 206 196
197 Moisture Entering Extruder % wb 18.2 -- 19.4 19.3 20.3 20.3
19.8 Estimated Retention Time in Preconditioner** min 4.8 5.8 5.8
5.8 5.8 5.8 5.8 EXTRUSION INFORMATION: Extruder Shaft Speed rpm 601
676 676 676 676 670 670 Motor Load % 92 96 89 81 71 88 91 Power
Usage kwh/ton 43 54 50 46 40 50 51 Water Flow to Extruder kg/hr 21
21 21 21 21 21 21 Control/Temperature-2nd Head .degree. F. Off/235
Off/268 Off/295 Off/310 Off/320 Off/215 Off/264
Control/Temperature-3rd Head .degree. F. Off/195 237 265 277 294
175 212 Head/Pressure kPa 10340 9310 8270 6900 5170 6210 6900 FINAL
PRODUCT INFORMATION: Wet Bulk Density g/l 447 447 448 480 460 490
455 Extruder Discharge Moisture % wb 1.5 -- 17.5 18.5 18.5 18.8
16.8 **Assumed 45% fill and 546 g/l bulk density
[0050] The extrudate product was analyzed and rated for industrial
acceptability. The results are shown in Table 3. As used in Table
3, PDI refers to "pellet durability index." PDI is an art
recognized durability test described in Feed Manufacturing
Technology IV, American Feed Association, Inc., 1994, pages 121-122
(and referenced information), incorporated by reference herein. In
such a durability test, the durability of pellets obtained
immediately after cooling when the pellets have a temperature
within 110.degree. F. of ambient temperature. Durability is
determined by tumbling a 500 g sample of pre-sieved pellets (to
remove fines) for 5 minutes at 50 rpm in a dust-tight
12".times.12".times.5" enclosure equipped with a 2".times.9"
internal plate affixed symmetrically along a 9" side to a diagonal
of one 12".times.12" of the enclosure. The enclosure is rotated
about an axis perpendicular to and centered on the 12" sides
thereof. After tumbling, the fines are removed by screening, and
the pellet sample is reweighed. Pellet durability is defined
as:
durability=weight of pellets after tumbling/weight of pellets
before tumbling.times.100
[0051] Industrial acceptability was based upon four industry
objectives: (1) PDI of 95 or greater; (2) fat and protein levels
each above 35% after coating; (3) extrude at the lowest possible
moisture levels to decrease drying costs, typically 18-20%; and (4)
maximum ingredient flexibility by reducing starch levels to
5-10%.
3TABLE 3 % Bulk Wheat % Soy Density Acceptable Sample % Starch %
Fat % Protein Flour Protein PDI (g/l) to Industry Run #1 18.2 7.4
46.6 26 0 96.5 484 yes Run #2 14.0 7.9 49.8 20 0 95.9 420 yes Run
#3 9.8 8.4 52.8 14 0 95.0 434 yes Run #4 4.9 9.0 55.8 7 0 95.0 491
yes Run #5 0 9.6 59.6 0 0 82.0 444 no Run #6 4.9 7.9 56.1 7 11.6
91.6 475 no Run #7 0 6.7 61.4 0 28.7 83.0 437 no Run #8 0 6.7 61.4
0 28.7 -- 560 no
[0052] The extrudate product was then vacuum spray coated with fish
oil and analyzed. The results are shown in Table 4.
4TABLE 4 % Bulk Max. Vacuum Wheat Density Fat Absorption Acceptable
Sample % Starch % Fat % Protein Flour (g/l) (%) to Industry Run #1
13.1 33.1 33.6 18.8 671 38.5 yes Run #2 9.2 39.4 32.8 13.2 638 51.9
yes Run #3 6.6 38.3 35.6 9.4 644 48.4 yes Run #4 3.6 32.7 41.2 5.2
664 35.3 yes Run #5 0 34.3 43.3 0 610 37.5 no Run #6 3.6 32.3 41.3
5.2 645 35.8 no Run #7 0 32.8 44.2 0 606 38.8 no Run #8 0 20.6 52.2
0 658 17.5 no
EXAMPLE 2
[0053] In this example, an extruder coupled with a preconditioner
of the type shown in FIG. 1 was used to manufacture a high quality,
dry dog food.
[0054] Specifically, the three-head extruder configuration used in
Run 8 was made up of the following components (where all parts are
identified with Wenger Mfg. Co. part numbers): extruder model
C.sup.2TX; extruder barrel-74002-424 (head No. 1); two 74002-425
(heads Nos. 2 and 3); Head No. 1 was equipped with sleeve
74002-421; Head No. 2 was equipped with sleeve 74002-422; Head No.
3 was equipped with sleeve 74002-423. Final die--65534-003 NA;
53672-003 AD; 31950-397 IN; 65421-003 BH; and 31350-779 IN. A
rotating knife assembly was positioned adjacent the outlet of the
die for cutting the extrudate into a convenient size. The knife
assembly included the following: 19462-015 (knife blade holder) and
twelve knife blades (19430-007).
[0055] In the case of Run 9, the extruder configuration was made up
of the following components: extruder model C.sup.2TX; extruder
barrel-74002-424 (head No. 1); two 74002-425 (heads Nos. 2 and 3);
Head No. 1 was equipped with sleeve 74002-421; Head No. 2 was
equipped with sleeve 74002-422; Head No. 3 was equipped with sleeve
74002-423. Final die--65534-003 NA; 53672-003 AD; 31950-400 IN;
65421-003 BH; and 31350-779 IN. A rotating knife assembly was
positioned adjacent the outlet of the die for cutting the extrudate
into a convenient size. The knife assembly included the following:
19462-015 (knife blade holder) and twelve knife blades
(19430-007).
[0056] In the case of Run 10, the extruder configuration was made
up of the following components: extruder model C.sup.2TX; extruder
barrel-74002-424 (head No. 1); two 74002-425 (heads Nos. 2 and 3);
Head No. 1 was equipped with sleeve 74002-421; Head No. 2 was
equipped with sleeve 74002-422; Head No. 3 was equipped with sleeve
74002-423. Final die--65534-003 NA; 53672-003 AD; 31950-399 IN;
65421-003 BH; and 31350-779 IN. A rotating knife assembly was
positioned adjacent the outlet of the die for cutting the extrudate
into a convenient size. The knife assembly included the following:
19462-015 (knife blade holder) and twelve knife blades
(19430-007).
[0057] In the case of Run 11, the extruder configuration was made
up of the following components: extruder model C.sup.2TX; extruder
barrel-74002-424 (head No. 1); two 74002-425 (heads Nos. 2 and 3);
Head No. 1 was equipped with sleeve 74002-421; Head No. 2 was
equipped with sleeve 74002-422; Head No. 3 was equipped with sleeve
74002-423. Final die--65534-009 AD; 65134-003 BD; 53672-003 AD;
31950-399 IN; 65421-003 BH; and 31350-779 IN. A rotating knife
assembly was positioned adjacent the outlet of the die for cutting
the extrudate into a convenient size. The knife assembly included
the following: 19462-015 (knife blade holder) and twelve knife
blades (19430-007).
[0058] The preconditioner used in all four of these setups was a
Wenger Model 54 DDC preconditioner having Configuration No. 377.
The left and right shafts were each equipped with a total of sixty
beaters.
[0059] In Runs 8-11 inclusive, the starting recipe was made up of
38.00% by weight corn, 18.00% by weight wheat midlings, 16.00% by
weight soybean meal, 8.00% by weight corn gluten, and 20.00% by
weight meat and bone meal.
[0060] The following table sets forth the operating conditions for
the preconditioner and extruder devices in the four runs.
5 TABLE 5 RUN RUN RUN RUN #8 #9 #10 #11 DRY RECIPE INFORMATION:
Feed Screw Seed rpm 36 50 40 45 PRECONDITIONING INFORMATION: Steam
Flow to Preconditioner kg/hr 155 186 160 1303 Water Flow to
Preconditioner lb/hr 770 440 510 1000 Preconditioner Discharge
Temp. .degree. F. 191 198 193 205 Moisture Entering Extruder % wb
23.04 20.2 -- 23.32 EXTRUSION INFORMATION: Extruder Shaft Speed rpm
600 600 600 600 Motor Load % 93 86 42 91 Control/Temperature-2nd
Head .degree. F. 219 226 245 -- Control/Temperature-3rd Head
.degree. F. 200 218 270 -- Head/Pressure kPa 1500 1200 1100 800
FINAL PRODUCT INFORMATION: Extruder Discharge Moisture % wb 22.06
23.05 23.44 23.97 Extruder Discharge Rate kg/hr 6545 7527 7527 7000
Extruder Discharge Density kg/m.sup.3 224 340 384 400 Extruder
Performance Stable Stable Stable Stable Final Product Description
Dog Dog Dog Dog Food Food Food Food Run Rating Good Good Good
--
EXAMPLE 3
[0061] In this example, an extruder in combination with a
preconditioner was employed in the manufacture of high quality
aquatic feed at commercial production rates.
[0062] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular, the extruder configuration
used in Run 12 was made up of the following components (where all
parts are identified with Wenger Mfg. Co. part numbers): extruder
model C.sup.2TX; extruder barrel-74002-424 (head No. 1); two
74002-425 (heads Nos. 2 and 3); Head No. 1 was equipped with sleeve
74002-421; Head No. 2 was equipped with sleeve 74002-422; Head No.
3 was equipped with sleeve 74002-423. Final die--65534-003 NA;
53672-003 AD; 31950-397 IN; and 65422-015 NA. A rotating knife
assembly was positioned adjacent the outlet of the die for cutting
the extrudate into a convenient size. The knife assembly included
the following: 19462-015 (knife blade holder) and twelve knife
blades (19430-007).
[0063] The preconditioner used in these runs was a Wenger Model 54
DDC preconditioner having configuration 377 with the right and left
shafts containing 60 beaters each.
[0064] The recipe used in Run #12 was 72.00% by weight fish meal,
26.00% by weight wheat flour, 1.00% by weight calcium phosphate,
and 1.00% by weight calcium carbonate.
[0065] The following table sets forth the operating conditions for
the preconditioner and extruder devices in the run.
6 TABLE 6 RUN #12 DRY RECIPE INFORMATION: Feed Screw Speed rpm 54
PRECONDITIONING INFORMATION: Steam Flow to Preconditioner kg/hr 405
Water Flow to Preconditioner lb/hr 325 Preconditioner Discharge
Temp. .degree. F. 202 EXTRUSION INFORMATION: Extruder Shaft Speed
rpm 609 Motor Load % 80 Head/Pressure kPa 1100 FINAL PRODUCT
INFORMATION: Extruder Discharge Rate kg/hr 6200 Final Product
Description Fish Food
EXAMPLE 4
[0066] In this example, an extruder was employed in the manufacture
of high quality corn based snack food at commercial production
rates.
[0067] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular, the extruder configuration
used in Runs 13 and 14 was made up of the following components
(where all parts are identified with Wenger Mfg. Co. part numbers):
extruder model C.sup.2TX; extruder barrel-74002-424 (head No. 1);
two 74002-425 (heads Nos. 2 and 3); Head No. 1 was equipped with
sleeve 74002-421; Head No. 2 was equipped with sleeve 74002-422;
Head No. 3 was equipped with sleeve 74002-423. Final die--65534-029
AD; 31950-399 IN; and 74010-959 BD. A rotating knife assembly was
positioned adjacent the outlet of the die for cutting the extrudate
into a convenient size. The knife assembly included the following:
19462-023 (knife blade holder) and five knife blades
(19430-007).
[0068] The recipe used in Runs #13 and #14 was 100.00% by weight
snack meal.
[0069] The following table sets forth the operating conditions for
the extruder device in the run.
7 TABLE 7 RUN #13 RUN #14 DRY RECIPE INFORMATION: Feed Screw Speed
rpm 999 999 EXTRUSION INFORMATION: Extruder Shaft Speed rpm 599 599
Motor Load % 43 44 Head/Pressure kPa 3/5516 3/5860.8 FINAL PRODUCT
INFORMATION: Extruder Discharge Rate kg/hr 460 -- Extruder
Discharge Density kg/m.sup.3 46 33 Run Rating Good Good Extruder
Performance Stable Stable Final Product Description Corn Corn
Curls/ Curls Balls
EXAMPLE 5
[0070] In this example, an extruder was employed in the manufacture
of high quality cooked grains (corn) at commercial production
rates.
[0071] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular, the extruder configuration
used in Runs 14-18 was made up of the following components (where
all parts are identified with Wenger Mfg. Co. part numbers):
extruder model C.sup.2TX; extruder barrel-74002-424 (head No. 1);
two 74002-425 (heads Nos. 2 and 3); Head No. 1 was equipped with
sleeve 74002-421; Head No. 2 was equipped with sleeve 74002-422;
Head No. 3 was equipped with sleeve 74002-423. Runs 15 and 16
employed a final die--74002-527 NA; 31950-399 IN; 65421-001 BH; and
31350-895 IN. Runs 17 and 18 employed a final die--74002-527 NA;
31950-356 IN; 65421-001 BH; and 31350-895 IN. A rotating knife
assembly was positioned adjacent the outlet of the die for cutting
the extrudate into a convenient size. The knife assembly included
the following: 19462-015 (knife blade holder) and twelve knife
blades (19430-007).
[0072] The preconditioner used in these runs was a Wenger Model 54
DDC preconditioner having configuration 377 with the right and left
shafts containing 60 beaters each.
[0073] The grain used in Runs #15-#18 was corn.
[0074] The following table sets forth the operating conditions for
the extruder device in the run.
8 TABLE 8 RUN RUN RUN RUN #15 #16 #17 #18 DRY RECIPE INFORMATION:
Feed Screw Seed rpm 20 11 21 21 PRECONDITTONER INFORMATION:
Preconditioner Speed rpm 250 250 250 250 Steam Flow to
Preconditioner kg/hr 407 129 530 603 Water Flow to Preconditioner
lb/hr 152 56 500 100 Preconditioner Discharge Temperature .degree.
F. 156 147 147 160 EXTRUSION INFORMATION: Extruder Shaft Speed rpm
600 604 600 613 Motor Load % 107 92 70 94 Water Flow to Extruder
lb/hr 100 -- 160 100 Control/Temperature 2nd Head .degree. F. 268
177 155 W/164 Control/Temperature 3rd Head .degree. F. 212 206 183
W/171 Head/Pressure kPa 13790 13790 6895 11721.5 FINAL PRODUCT
INFORMATION: Extruder Discharge Rate kg/hr 3338.44 -- -- 3265.86
Extruder Discharge Density kg/m.sup.3 390 144 593 481 Final Product
Description Corn Corn Corn Corn
EXAMPLE 6
[0075] In this example, an extruder was employed in the manufacture
of high quality cooked grains (general/mixed) at commercial
production rates.
[0076] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular, the extruder configuration
used in Runs 19 and 20 was made up of the following components
(where all parts are identified with Wenger Mfg. Co. part numbers):
extruder model C.sup.2TX; extruder barrel-74002-424 (head No. 1);
two 74002-425 (heads Nos. 2 and 3); Head No. 1 was equipped with
sleeve 74002-421; Head No. 2 was equipped with sleeve 74002-422;
Head No. 3 was equipped with sleeve 74002-423. Final die--74002-527
NA; 31950-356 IN; 65421-001 BH; and 31350-895 IN. A rotating knife
assembly was positioned adjacent the outlet of the die for cutting
the extrudate into a convenient size. The knife assembly included
the following: 19462-015 (knife blade holder) and twelve knife
blades (19430-007).
[0077] The preconditioner used in these runs was a Wenger Model 54
DDC preconditioner having configuration 377 with the right and left
shafts containing 60 beaters each. The extruded product was then
dried.
[0078] The following table sets forth the operating conditions for
the extruder device in the run.
9 TABLE 9 Run #19 Run #20 DRY RECIPE INFORMATION: Feed Screw Speed
rpm 21 12 PRECONDITIONER INFORMATION: Preconditioner Speed rpm 250
250 Steam Flow to Preconditioner kg/hr 550 766 Water Flow to
Preconditioner lb/hr 300 -- Preconditioner Discharge Temperature
.degree. F. 170 192 EXTRUSION INFORMATION: Extruder Shaft Speed rpm
613 613 Motor Load % 105 80 Water Flow to Extruder lb/hr 100 25
Control/Temperature 2nd Head .degree. F. W/178 W/175
Control/Temperature 3rd Head .degree. F. W/182 Head/Pressure kPa
11721.5 11721.5 DRYER INFORMATION: Zone 1 Temperature .degree. C.
110 110 Zone 2 Temperature .degree. C. 110 110 Retention Time--Pass
1 min 9 9 Retention Time--Pass 2 min 11 11 Fan Speed 1 rpm 1800
1800 Fan Speed 2 rpm 1800 1800 Fan Speed 3 rpm 1800 1800 Fan Speed
4 rpm 1800 1800 FINAL PRODUCT INFORMATION: Extruder Discharge Rate
kg/hr 453.59 406 Extruder Discharge Density kg/m.sup.3 593 150
Final Product Description Rice Rice
EXAMPLE 7
[0079] In this example, an extruder was employed in the manufacture
of high quality bird feed at commercial production rates.
[0080] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular runs #21-28 used the
following common components (where all parts are identified with
Wenger Mfg. Co. part numbers): extruder model C.sup.2TX; extruder
barrel-74002-424 (head No. 1); two 74002-425 (heads Nos. 2 and 3);
Head No. 1 was equipped with sleeve 74002-421; Head No. 2 was
equipped with sleeve 74002-422; Head No. 3 was equipped with sleeve
74002-423. The runs employed final die assemblies as noted in the
table below (all parts identified with Wenger Mfg. Co. part
numbers):
10 TABLE 10 Runs #21-#22 Run #23 Runs #24-#25 Run #26 Run #27-#28
Final 74002-527 NA 74002-527 NA 74002-527 NA 74002-527 NA 74002-527
NA die 31950-356 IN 65534-029 AD 65534-029 AD 31950-597 IN
31950-597 IN 65422-097 BD 65421-001 BH 31950-399 IN 65421-001 BH
65422-001 BD 74010-587 NA 65421-001 BH 65534-029 AD 31950-356
IN
[0081] A rotating knife assembly was positioned adjacent the outlet
of the die for cutting the extrudate into a convenient size. The
knife assembly included the following: 19462-015 (knife blade
holder) and twelve knife blades (19430-007).
[0082] The preconditioner used in these runs was a Wenger Model 54
DDC preconditioner having configuration 377 with the right and left
shafts containing 60 beaters each. The extruded product was then
dried.
[0083] The following table sets forth the operating conditions for
the extruder device in the run.
11 TABLE 11 Run Run Run Run Run Run Run Run #21 #22 #23 #24 #25 #26
#27 #28 DRY RECIPE INFORMATION: Feed Screw Seed rpm 15 10 11 10 10
10 10 10 PRECONDITIONING INFORMATION: Preconditioner Speed rpm 250
250 250 250 250 250 250 -- Steam Flow to Preconditioner kg/hr 158
870 913 600 600 600 173 142 Water Flow to Preconditioner lb/hr 350
-- 450 -- 340 200 -- -- Preconditioner Additive 1 Rate kg/hr -- --
-- -- 58 2100 -- -- Preconditioner Discharge Temp. .degree. F. 158
-- -- 189 189 191 -- 169 EXTRUSION INFORMATION: Extruder Shaft
Speed rpm 600 600 610 600 600 625 581 593 Motor Load % 43 37 24 62
40 47 70 95 WaterFlowtoExtruder lb/hr 100 -- 100 -- 100 100 80 50
Control/Temperature-2nd Head .degree. F. W/119 W W/154 W/254 W/273
W/262 W/292 -- Control/Temperature-3rd Head .degree. F. W/145 W/174
W/138 W/174 W/172 W/168 W/182 -- Head/Pressure kPa 3447.5 5516 2758
11032 6205.5 7584.5 13790 13790 DRYER INFORMATION: Zone 1
Temperature .degree. C. 110 110 130 125 125 125 105 90 Zone 2
Temperature .degree. C. 110 110 130 125 125 125 105 90 Retention
Time-Pass 1 min 6 6 7.1 7.1 7.1 7.1 7.1 7.1 Retention Time-Pass 2
min 9.1 9.1 9.1 9.1 9.1 9.1 9.1 9.1 Dryer Discharge Moisture % wb
8.94 3.59 8.71 2.75 3.34 2.94 1.72 4.18 Fan Speed 1 rpm 2110 2110
2110 2110 2110 2110 2110 1825 Fan Speed 2 rpm 2110 2110 2110 2110
2110 2110 2110 1815 Fan Speed 3 rpm 2060 2060 2060 2060 2060 2060
2060 1800 Fan Speed 4 rpm 2095 2095 2095 2060 2060 2060 2095 1800
FINAL PRODUCT INFORMATION: Extruder Discharge Rate kg/hr 3469 -- --
1818 1818 -- 1658 -- Extruder Performance -- -- -- -- -- -- --
Unstable Extruder Discharge Density kg/m.sup.3 561 497 570 260 352
390 230 216.35 Final Product Description KT Test KT Test KT Test KT
Test KT Test KT Test KT KT Test Test- .062
EXAMPLE 8
[0084] In this example, an extruder was employed in the manufacture
of high quality dog food at commercial production rates.
[0085] The extruder was of the type depicted in FIG. 1, and
consisted of three heads. In particular, the extruder configuration
used in Runs 29-31 was made up of the following components (where
all parts are identified with Wenger Mfg. Co. part numbers):
extruder model C.sup.2TX; extruder barrel-74002-424 (head No. 1);
two 74002-425 (heads Nos. 2 and 3); Head No. 1 was equipped with
sleeve 74002-421; Head No. 2 was equipped with sleeve 74002-422;
Head No. 3 was equipped with sleeve 74002-423. Final die--74002-527
NA; 65534-029 AD; 31950-399 IN; and 65422-199 BD. A rotating knife
assembly was positioned adjacent the outlet of the die for cutting
the extrudate into a convenient size. The knife assembly included
the following: 19462-023 (knife blade holder) and ten knife blades
(19430-007).
[0086] The preconditioner used in these runs was a Wenger Model 54
DDC preconditioner having configuration 377 with the right and left
shafts containing 60 beaters each. The extruded product of runs 29
and 30 was then dried.
[0087] The following table sets forth the operating conditions for
the extruder device in the run.
12 TABLE 12 Run #29 Run #30 Run #31 DRY RECIPE INFORMATION: Feed
Screw Speed rpm 29 39 25 PRECONDITIONER INFORMATION: Preconditioner
Speed rpm 250 250 250 Steam Flow to kg/hr 932 1049 1183
Preconditioner Water Flow to lb/hr 500 770 470 Preconditioner
Preconditioner Additive kg/hr 89 125 -- 1 Rate Preconditioner
Discharge .degree. F. 188 180 202 Temperature EXTRUSION
INFORMATION: Extruder Shaft Speed rpm 600 728 600 Motor Load % 50
70 62 Water Flow to Extruder lb/hr -- -- 100 Control/Temperature
.degree. F. W/251 W/251 W/279 2nd Head Control/Temperature .degree.
F. W/155 W/153 W/172 3rd Head Head/Pressure kPa 4826.5 4826.5 4137
DRYER INFORMATION: Zone 1 Temperature .degree. C. 130 135 -- Zone 2
Temperature .degree. C. 130 135 -- Retention Time--Pass 1 min 9.2
5.7 -- Retention Time--Pass 2 min 11.2 9.6 -- Dryer Discharge
Moisture % wb 13.28 8.32 -- Fan Speed 1 rpm 1815 2335 -- Fan Speed
2 rpm 1815 2305 -- Fan Speed 3 rpm 1805 2355 -- Fan Speed 4 rpm
1800 2360 -- FINAL PRODUCT INFORMATION: Extruder Discharge Rate
kg/hr -- 8040 -- Extruder Discharge Density kg/m.sup.3 481 450 424
Extruder Performance -- Stable Stable Final Product Description Dog
ZD Dog ZD --
[0088] Embodiment of FIGS. 7-10
[0089] FIGS. 7-10 illustrate a twin screw extruder 14 as previously
described, in combination with an improved die assembly 88, the
latter being mounted on the front face of barrel head 32. Broadly,
the assembly 88 includes a tubular barrel 90 presenting an internal
passageway 91, an outwardly flared output opening 92, and a pair of
concentric, opposed, upwardly and downwardly extending tubular
extensions 94, 96. As best seen in FIGS. 7 and 9, the rearward end
of barrel 90 is flanged to mate with the end of barrel section 32,
and bolts 98 are employed to connect the barrel in place. As
depicted in FIG. 8, a conventional, apertured die plate 100 is
normally secured to the forward end of the barrel 90, across output
opening 92.
[0090] The assembly 88 further includes a vertically shiftable
valve stem 102 situated within the extensions 94, 96, and extending
across the passageway 91. The stem 102 includes a central through
opening 104 which is sized so that, when the stem is positioned as
illustrated in FIG. 7, the opening 104 is concentric with and of
the same diameter as passageway 91. In addition, the stem has a
downwardly extending tubular leg 106 which communicates with an
upper opening 108, the latter also being sized to mate with
passageway 91 when the stem is in the position illustrated in FIG.
9. The stem 102 is equipped with an upwardly extending cylindrical
block portion 110 above opening 104. The block portion 110 supports
a guide 112 and has a central threaded bore 114 adjacent the upper
end thereof. As best seen in FIGS. 7 and 9, the extensions 94, 96
have conventional O-ring seals 116, 118 adjacent the outer ends
thereof, to provide a seal between the extensions and stem 102.
[0091] A drive assembly 120 is provided for the stem 102 and
includes a piston and cylinder unit 122 positioned above block
portion 110. The unit 122 includes a cylinder 123 equipped with
apertured top and bottom walls 123a, 123b, and an extensible piston
rod 124, the latter passing through guide 112 and being threaded
into block portion 110. The unit 122 is supported by bolt
connections to a pair of upstanding sidewalls 126, 128 (see FIG.
10), the latter being secured to extension 94. In order to assist
in determining the position of stem 102, the outer end of piston
rod 124 has a pointer 130, and a rule 132 is secured to top wall
123a. Up and down reciprocation of stem 102 is guided by means of
plate 112 slidably received between two upright plates 134, 136
which are connected to extension 94 and plate 123a.
[0092] In the use of assembly 88, the stem 102 is infinitely
adjustable through the piston and cylinder unit 122. During
steady-state extrusion running, the stem 102 may be in the FIG. 7
position, i.e., with the opening 104 concentric with passageway 91.
This orientation presents minimum restriction to flow of material
passing through the extruder. However, if more back pressure is
desired, the stem 102 may be raised or lowered slightly to effect
partial blockage of the opening 104. Additionally, during startup
operations or in the course of a changeover between extruder
recipes, it may be desirable to dump the material from the extruder
barrel. This is accomplished by elevating the stem 102 to the FIG.
9 position, where the opening 108 is in full communication with
passageway 91. In this condition, the scrap material is diverted
downwardly through tubular leg 106. Once acceptable product is
being created, then of course the stem 102 is lowered to the FIG. 7
position or some intermediate position based upon desired running
condition.
[0093] Embodiment of FIGS. 11-14
[0094] FIGS. 11-14 illustrate an embodiment of the invention
especially designed for extraction of oil from oil seeds, e.g.,
extraction of soybean oil from full-fat soy meal or soybeans. In
this instance, the extruder 138 is a three-head design, as in the
case of previously described extruder 14. Moreover, apart from
final head 32, the extruder 138 is identical with the extruder 14,
and like reference numerals have been applied in FIG. 11. More
broadly, in this aspect of the invention, use is made of one or
more extraction heads similar to identical to the final head 32.
Although not shown in the drawings, the assembly 88 is preferably
mounted adjacent the outer end of the extruder barrel.
[0095] Referring to FIGS. 11 and 12, it will be seen that the
extruder 138 has a modified third or final head 140 which is bolted
to head 30 via bolts 142. The head 140 includes an outer circular
shell 144 having a lowermost tubular fluid outlet 146; the shell
144 is supported by spaced apart head plates 148, 150. In addition,
the head 140 includes an internal, slotted extraction sleeve 152
which is made up of a series of interconnected, aligned bar
elements 154 (see FIG. 13). The sleeve 152 is of tapered
configuration and is mounted within generally oval openings 156,
158 formed in head plates 148 and 150, respectively. The interior
surface 160 of sleeve 152 is of horizontal, generally "FIG. 8"
design, and is tapered from plate 148 to plate 150, so as to
accommodate the sections of twin screw assembly 122.
[0096] The sleeve 152 is formed of bar elements 154, each such bar
element having an inner surface 162, an outer surface 164, a
forward connection block 166, a rearward connection block 168, and
a recess 170 between the blocks 166, 168. The surface 169 of
element 154 remote from recess 170 is planar throughout the length
of the bar element. It will be observed that the inner surface 162
of each bar element is shorter in length than the corresponding
outer surface 164, i.e., the radius of curvature of the surface 162
is smaller than that of the outer surface 164. FIG. 14 illustrates
a pair of side-by-side bar elements 154a and 154b, which are
interconnected by welding or other connection means at the regions
of the blocks 166a, 166b and 168a, 168b. However, owing to the
recess 170a formed in the bar element 154a, and the adjacent planar
surface 169b, a through passageway 172 is defined between the bar
elements 154a and 154b.
[0097] As indicated, the entirety of sleeve 152 is made up of bar
elements with through passageways between adjacent bar elements.
The bar elements are configured so that the through passageways are
tapered from the inner surface 160 of the sleeve 152 to the outer
surface thereof. In one embodiment, the width of the passageways
adjacent the inner surface of the sleeve is approximately 0.003
inch (and should range from about 0.001-0.065 inch). In this way,
the extracted fluid may pass through the passageways, but little or
none of the solid material passing through the sleeve can migrate
through the passageways. As best seen in FIG. 12, the bar elements
at the upper and lower central regions 174 of the sleeve 152 are
substantially of constant thickness, whereas those at the side
arcuate sections 176 of the sleeve are themselves tapered.
[0098] The outer end of the extruder 138 includes an intermediate
plate 178 having a through opening 180, as well as a die mounting
plate 182 presenting an outwardly flared opening 184. The plates
178, 182 are secured to plate 150 by means of bolts 186. Although
not shown, it will be appreciated that an apertured die plate may
be affixed to the outer surface of plate 182 across opening 184, or
more preferably the die assembly 88.
[0099] In the use of extruder 138, a material to be defatted is
passed through the extruder 138 where it is subjected to increasing
temperature, pressure and shear in the first two heads 28 and 30.
As the material enters the third head 140, the action of the screw
assembly 128 causes oil within the oil seed material to be pressed
or extruded through the passageway 172 provided between adjacent
bar elements 154. This oil is collected within the shell 144 and is
drained via outlet 146 for downstream processing (e.g., flashing
and extraction). Of course, where appropriate a pump may be
operatively coupled with outlet 146. After the de-oiled material
passes through the sleeve 152, it moves through the openings 180,
184 (and if present, a die plate or the assembly 88).
[0100] A particularly preferred extraction technique using extruder
138 is supercritical extraction wherein an extractant such as
carbon dioxide or propane, or mixtures thereof, is injected into
head 140 (or upstream thereof into heads 28 or 30) through
injectors (not shown) where the extractant is injected under
supercritical temperature/pressure conditions. Such supercritical
extraction results in an increase in efficiency, because the
supercritical extractant is more missible with the oil and lowers
the oil viscosity, allowing it to be more easily dispelled through
the sleeve 152. Further, the defatted meal is of higher quality
because use of supercritical fluids lowers the temperature of the
meal preventing overheating thereof. This same effect inhibits
oxidation of the extracted oil because of the substantial absence
of oxygen.
[0101] Where supercritical extraction is desired, it is often
useful to attach a pressure regulating valve to the outlet 146 in
order to maintain pressure conditions within the head 32 (of course
the "plug" of material passing through the sleeve 152 prevents
venting of supercritical fluid rearwardly or forwardly from the
sleeve). By way of illustration only, where carbon dioxide is used
as a supercritical extractant, the pressure conditions within the
sleeve 152 may be maintained at a level of around 1500 psi, whereas
within the shell 144, the pressure may be on the order of 1000 psi
(i.e., there is about a 500 psi pressure drop across the sleeve
152). Furthermore, it is contemplated that a series of spaced
pressure regulating valves can be attached to the outlet 146 so as
to permit cascade recovery of different products at different,
successively lower pressures.
[0102] While the extruder 138 has particular utility for the
extraction of oils, it could also be used for extraction of special
tea or herb materials.
* * * * *