Note: Descriptions are shown in the official language in which they were submitted.
1377~; ~
1 This invention relates to tubular collagen products
2 such as sausage casings, and more particularly, to improved
3 tubular collagen products and to methods and apparatus for making ¦
4 such tubular collagen products.
The products of the invention, after suitable finishing
6 treatments, are particularly adapted to be utilized as an edible
7 casing for fresh pork sausage which must be cooked before they are
8 consumed, as well as sausages of the weiner or frankfurter type.
9 The latter type sausages are generally processed by being smoked
and cooked by the packer and are generally merely reheated before
11 they are consumed. When sausages are provided with edible casings ¦
12 it is unnecessaryto remove the casing before the sausage is eaten.
13 Naturai casings produced from the intestines of sheep,
14 hogs and cattle have certain inherent shortcomings including
nonuniformity and porosity of casing wall, variations in casing
16 size and edibility, and wide fluctuations in market price and
17 availability. Except for some made from sheep intestines, they
18 are tough and hard to masticate. Also, natural casings are
19 difficult to clean and prepare for human consumption. In addition
the thickness of the wall and diameter of natural casings will
21 vary, causing difficulty during modern high speed stuffing. In
22 view of these deficiences, many attempts have been made to pro-
23 duce better edible casings from protein sources such as collagen.
24 There are commercially available at this time tubular
collagen products such as sausage casing. However, the use of
26 collagen casings in the production of sausages and similar items
27 on extremely high speed automatic equipment has had only limited
28 success. Thus, collagen casings exhibiting tenderness are subject
29 to excessive machine breakage while casings strong enough to
machine well are tough and may not be generally acceptable as an
31 edible item.
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1 ¦ Prior Art Practices
2 1 United States Patent No. 3,122,788, granted March 3, 1964
3 to Emanuel Roy Lieberman describes many of the prior practices to
4 produce tubular collagen products for use as sausage casings. Thei - : aforementioned Lieberman patent is specifically directed to an
6 apparatus and method for producing collagen tubing by a continuous
7 extrusion operation and is in commercial use today. It also des-
8 cribes an extruder mechanism and process for making such collagen
; 9 casings.
It is known to those skilled in the art that collagen
11 has unique rheological characteristics. Thus, when acid swollen
12 collagen gel (sometimes also called "extrusion mass" or "dispersion
13 in prior art patents) is fed through an extruder, there is a ten-
14 dency of the swollen collagen fibrils and/or fibers to mat togetherl
and become oriented in the direction of the extruder flow. Further,
16 it has been found that when the collagen is formed into a tubular
17 construction, certain orientation occurs which cause the casing
18 to split or tear in the direction of this orientation.
19 ¦ Thus, it has been known that one of the major causes of
weak spots in extruded collagen casings is the tendency of the
21 collagen fibrils and/or fibers to become oriented in the direction
22 of collagen flow when such fibrils and/or fibers accidentally
23 encounter an obstacle in their path of travel during extrusion.
24 For example, this characteristLc may manifest itseIf in a generally
longitudinal seam or fault in the casing wall. -
26 Another phenomena that occurs in treating swollen
27 collagen material, whether fibrous of fibrillar, is that when a
28 fluid collagen mass undergoes conditions of flow, it is affected -
29 in such a manner that it "remembers" the boundary conditions under
30 which i has been flowed. Thus it has been fo~nd that vl~en two
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1 such fluid masses are brought into contact with each other, the
2 boundary area defined by their contacting surfaces continues in
3 the fluid mass and persists even in forms, e.g. tubular, into
4 which such mass is subsequently extruded or otherwise shaped. It
has heretofore been thought that the formation of such boundary
6 areas in articles extruded from collagen masses creates areas of
7 weakness which weaken the product formed in this manner.
8 For example, if a fluid mass of swollen collagen fibrils
is caused to flow into an annular cavity, such as by extrusion,
from a peripheral inlet whereby the flowing mass is divided and
11 thereafter the divided streams are caused to flow together, the
12 area where the divided streams meet and merge remains in the memor
13 of the material as a persistent boundary area and becomes, in
14 ultimate use, an area of weakness.
The aforementioned Lieberman patent attempted to overcome -;
16 the foregoing inherent problems and difficulties occuring when the
17 swollen collagen was subjected to extrusion by an extrusion appara-
18 tus and method which subjected the swollen collagen mass to forces
19 to effect a random orientation of the collagen to eliminate the
above-mentioned problems inherent in extruding swollen collagen.
21 Thus, in the extruder of the 3,122,788 patent, care is taken to
22 erase the previous memory by using a rotating disk.
23 The Present Invention
.,
24 In order to define the invention so that it will be
clearly understood, certain terms are used herein which are
26 defined as follows:
27 The term "rope" refers to the shape of the collagen gel
28 after it has been forced through a small orifice, whereupon in
29 appearance it resembles a rope or a piece of spaghetti in that it
¦ is relatively long in relation to its diameter which is relatively
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1 small. The fibrils and/or fibers of collagen present on the
2 external surface of the rope will be mainly oriented in the
3 longitudinal direction as a result of the forces to which the
4 collagen gel is subjected to during its passage through the orific~ .
The collagen fibrils and/or fibers present in the interior portions
6 of the ropes may have any orientation and probably are closest to
7 a random orientation.
8 The term "layer" as used herein refers to a set or
9 plurality of ropes of collagen gel, which ropes are oriented
generally in the same direction as each other and are roughly
11 parallel to each other.
12 The term "hardened layers" as used herein refers to the
13 layers as they exist in the finished casing. In the hardened
14 layers of the final casing, the collagen, as will be explained
in detail subsequently, has been formed into a casing whose thick-
16 ness is considerably smaller than the diameter of the original
17 ropes. The layers and, more particularly, the ropes of which the
18 layers are formed, during the manufacturing process, have been
19 flattened by the shearLng action of two counter-rotating extruders,
by the width of the annular space between the extruders, and by the
21 hardening and drying action of the finished casing, 80 that the
22 ropes in the finished casing are no longer spaghetti-like in appe r-
23 ance, but are somewhat irregular in cross-section. The ropes do
24 not, at this time, exist in discrete orm since they have been par-
tially merged in their boundary areas with ad~acent ropes and with
26 one somewhat flattened rope perhaps slightly overlapping an
adjacent rope. Yet, because of the longitudinal orientation of
28 the majority of the fibrils and/or fibers present on the external
29 surface of the ropes making up the layers, the outline of the
ropes remain detectable in tbe final casing, at least when the
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cas ng is wet. ~ollowing the process according to this invention
2 ¦ the product is subject to further treatment. This further treat-
3 ment results in a neutralization of the acid swollen gel, a
4 removal of much of its water content, and a hardening of the
.. 5 tubular structure into a casing which is then dried.
6 The present invention is in direct contrast to the
7 ¦ teachings of the aforementioned Lieberman patent.
8 ¦ In accordance with the present invention, no effort is
9 1 made to obtain random orientation of the collagen fibrils
10 ¦ and/or fibers. According to the present invention, the
11 1 inherent characteristics of swollen collagen, to become
12 oriented and to "remember" or have "memory" is utilized to
13 form a tubular collagen casing which is stronger than casings
14 made according to the aforementioned Lieberman patent and yet is
15 tender and edible. The present invention therefore utilizes what :
16 heretofore has been thought of as undesirable characteristics of
17 swollen collagen to form a stronger tubular collagen casing which :
18 can be successfully machined on extremely high speed automatic :-
19 sausage making equipment. .-
.~ 20 In accordance with the present invention, the swollen
21 collagen is subjected to mechanical force so that the fibrils
- 22 and/or fibers become oriented in the direction of flow of the .
23 ¦ collagen. The swollen collagen is, .thereafter, formed into a .. :
~ 24 j tubular construction wherein the orientation of the fibrils and/or
1 -25 ¦ fibers serves to strengthen the tube against bursting or splitting
26 ; while at the same time remaining edible.
27 In accordance with the invention, the swollen collagen,
28 sometimes hereafter referred to as the "gel", is provided in the
29 form of an inner gel and an outer gel. To obtain the advantages
~of the w thin invention the~e ael~ may have identic~l or different
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111377~i
1 formulations. The inner and outer gels are then subjected to ~-
2 mechanical force, such as by extrusion, so that each of the gels
3 1 is formed into a plurality of individual ropes of gel. More
4 ¦ particularly, the ropes are formed by passing the two gels
through counter-rotating extrusion members having a plurality
6 of orifices corresponding in number to the number of ropes to be
7 formed. Typically, each of the gels is formed into a multiplicity
8 e.g. thirty-two, ropes, although more or less ropes may be employed
9 as will be described more fully hereinafter.
When the inner and outer gels are formed into the above-
11 described multiplicity of small ropes, the fibrils and/or fibers
12 ¦ in the swollen collagen become oriented in the direction of extru-
13 sion. After the outer and inner gels have been formed into the
14 plurality of ropes, the outer and inner gels are brought together
to form a single fluid mass having a substantially annular cross-
16 section with ropes from the outer gel being predominantly located
17 adjacent the outer surface of the annulus and the ropes from
18 the inner gel being predominantly located adjacent the lnner
19 ¦ surface of the annulus. The annular fluid mass of gel is then~
20 ¦ passed between two counter-rotating cylindrical surfaces to form
21 1 a tube and then is exited through an annular stabilizing orifice
22 which sizes the tubular product.
23 ~uring this passage between the counter-rotating surfaces
24 the ropes from the outer gel remain located adjacent the outer
surface of the resultant tube while the ropes from the inner gel
26 remain adjacent the inner surface thereby forming a tube comprising
27 an outer layer consisting predominantly of the outer gel and an
28 inner layer consisting predominantly of the inner gel. It has
29 ¦ been found that although all the ropes have been united in this
¦ space, the memory characteristics of the fibrils and/or fibers
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~13776
1 prevents such ropes from being destroyed. In fact, upon exit
2 from the two counter-rotating surfaces and the stabilizing annulusl
3 the inner gel ropes will be helically oriented or directed in one ¦
4 direction whereas the outer gel ropes will be helically oriented
or directed in the opposite direction. Thus, the resulting tube
consists of two layers each containing ropes oriented in opposing
7 ¦ directions and forming a net-like structure.
8 1 It has been observed that these layers remain discrete
9 1 layers even after subsequent treatment and that these layers can
10 ¦ be separated from one another.
11 ; Stated in other words, the inner and outer gels of
12 swollen collagen are each divided into a multitude, e.g. thirty-
13 two ropes by extruding the swollen collagen through two counter
14 rotating series of orifices. As the two layers thus generated
are forced through the extruder, they are formed into concentric
16 helices of opposite direction about the longitudinal axis of the
17 casing. As the casing is hardened, the "memory" of these ropes
18 persists and the outline of the hardened ropes may be detected -
19 ¦ in hardened layers of the finished product. Since the
ropes from the inner and outer gel are formed into opposing
21 concentric helices, they appear net-like in the casing wall. The
22 net-like structure so formed permits the two layers to reinforce
23 each other enabling a high stress resistance to be obtained in the
24 finished product.
Thus, in accordance with this invention, even though
26 the two sets of ropes of gels have been brought together to
27 apparently form a single fluid mass of gel while between the
28 counter-rotating surfaces, the inherent characteristics of orienta-
29 tion and memory causes the gels to be discharged from the counter-
rotating surfaces in two layers still consisting of the same
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111377~ 1
1 l plurality of ropes into which they were orlginally formed. Furthe;r
2 !~ the orientation of the fibrils and/or fibers resulting from the
3 extrusion through the small orifices remains despite the additional
4 mechanical work and subsequent treatment of the collagen gel.
5 i¦ In short, the collagen gel is subjected to ~Lechanical
6 ¦ force which causes a certain orientation which because of the
7 1 memory characteristics of the collagen gel persists in the final
8 product.
9 1! Thus~ the fibrils and/or fibers becbme oriented along
10 ¦l the length of the spaghetti-like rope as a result of being ex-
11 I truded through the small orifices. Next, the layers of ropes are
12 1 helically oriented in opposite directions as a result of passing
13 ~ between the counter-rotating extrusion members. These orienta-
14 1 tions persist in the final product. However, as noted previouslyJ
5 l the ropes tend to beco~Le flattened somewhat as a result of pass-
16 1 ing between the concentric counter-rotating surfaces and as a re-
17 ¦ sult of the subsequent treatment. Also, it is possible that as a
18 ~¦ result of the wiping action of the concentric counter-rotating
19 ¦¦ surfaces some disorientation of the fibrils and/or fibers may occ- Lr.
20 ! Hence, upon discharge, there will be one layer of ropes
21 ¦ helically directed in one direction and a second layer of ropes -
22 j helically directed in the opposite direction. The helical angle
23 ! can be controlled to produce any angle in the net-like structure ¦
24lofthecasing
25~l Objects
26 ¦~ In view of the foregoing, it is an ob3ect of this
27 ¦ invention to provide a new and improved tubular collagen casing
28 ¦ having a strùcture resulting in enhanced strength and a method
29 ¦ and apparatus for forming the same.
Another object of this invention is to provide a new an~
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1113776
improved edible collagen casing for sausages and the like
having a unique organization of the collagen fibrils and/or
fibers resulting in enhanced strength characteristics and
methods and apparatus for making the same.
Another object of this invention is to provide a
new and improved edible tubular collagen casing for sausages
and the like wherein the casing is formed of a unique net-like
structure including two layers of ropes of collagen which are
oppositely helically directed and overlapping to form a
tubular casing having enhanced strength and methods and
apparatus for making the same.
Another object of this invention is to provide a
novel method of forming a tubular col~ gen casing which
includes forming two sets of a plurality of ropes by
extrusion thereby orienting the fibrils and/or fibers in the
direction of movement, un~ting said sets of ropes into a
single fluid mass and subjecting said mass to counter-
rotating surfaces and thereafter forming said stream into
a tubular construction where the original groups of ropes
are detectable.
Another object of this invention is to provide
a method of making a tubular collagen casing comprising:
(a) directing an inner collagen gel and an outer collagen gel
to an extruder: (b) feeding the inner gel radially outwardly
through a first group of radially extending orifices to form
a plurality of inner gel ropes: (c) feeding the outer gel
radially inwardly through a second group of radially extend- -
ing orifices to form a plurality of outer gel ropes (d)
bringing said radially inwardly directed outer gel and said
radially outwardly directed inner gel together to form a
fluid mass having a substantially annular cross section with
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1~137'7~i
the ropes from the outer gel being predominantly located
adjacent the outer border of the annulus and the ropes from
the inner gel being predominantly located adjacent the inner
border of the annulus, and (e) feeding the annular mass
between two counter-rotating concentric surfaces to thereby
direct said outer gel ropes and said inner gel ropes in
opposite helical directions and form a two-layered tubular
casing.
A still further object of this invention is to
provide an extruder apparatus which includes two counter-
rotating extruders each having a series of orifices (memory
nozzles) therein which divides the two main gel sources
into a plurality of ropes which ropes are discharged from the
extruder to form a tubular casing wherein the casing consists
of a net-like structure of ropes formed in layers wherein -
the ropes of said layers are helically directed in opposite
directions.
Another object of this invention is to provide
- an apparatus for forming a tubular collagen casing comprising:
(a) a stationary frame, ~b) a stationary member mounted on
said frame, (c) an inner hollow extruder-member mounted on
said frame, said inner hollow extruder member having a plura-
lity of radially extending orifices therethough for directing
collagen outwardly, (d) means for mounting said inner extruder
member on said frame concentric with respect to said stationa-
ry member and spaced outwardly therefrom, (e) an outer extru-
der member having a plurality of radially extending orifices
therethrough for directing collagen inwardly; (f) means for
mounting said outer extruder member on said frame concentric
with respect to said inner extruder member and spaced out-
wardly therefrom to form a passageway therebetween for merging
said collagen of said inwardly and outwardly directions, and
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111377~
(g) means for rotating said inner extruder member in one
direction and means for rotating the outer extruder member
in the opposite direction. '~
Another object of this invention is to provide a new
and novel process for forming collagen gel into a net-like
casing for use with sausages and the like.
A further object of this invention is to provide a '
smooth surfaced collagen casing having a net-like non-porous
tubular structure comprising two concentric layers united in
an overlapping relationship with one another, each of said
layers possessing a plurality of collagen ropes helically
oriented in a direction opposite to the ropes in the other,of
said layers, said collagen ropes having fibrils and/or fibers
which, at least on the outside surface of said ropes, are sub-
stantially aligned in the direction of the ropes.
A further object of this invention is to provide a new
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111377~i ~
1 and novel extrusion apparatus for forming collagen gel into a
2 ¦ casing for use with sausages and the like.
3 Other objects and advantages of the invention will be
4 obvious or may be learned by practice of the invention, the same
being realized and attained by means of the instrumentalities and
6 combinations particularly pointed out in the appended claims.
7 The invention consists in the novel steps, constructions,
8 arrangements, combinations and improvements herein shown and des-
9 cribed.
The accompanying drawings referred to and constituting
11 a part hereof, illustrate an embodiment of the invention and
12 together with the description, serve to explain the principle
13 ¦ of the invention.
14 ¦ OF THE DRAWINGS:
FIGURE 1 is a diagrammatic flow diagram illustrating,
16 in general, the method of extruding gels in accordance with this
17 invention.
18 FIGURE 2 is a schematic perspective view of a portion
19 of the finished end product of this invention.
FIGURE 2A is a schematic end view of the product shown
21 in Figure 2.
22 FIGURE 3 is an end view of the forward portion of the
23 machine.
24 FIGURE 4 is an end view of the exit end of the machine.
FIGURE 5A is a vertical section of the forward portion
26 of the machine, taken generally along line 5A - 5A of Figure 3.
27 FIGURE 5B is a vertical section of the exit portion
28 of the machine, this figure being a continuation of Figure 5Af
29 and is taken generally along line 5B - 5B of Figure 4.
FIGURE 6 is a vertical section taken along line 6 - 6
31 of Figure 5A, and shows the drive mechanism for rotation of the
32 1 inner extruder member.
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1 ~ FIGUR~ 7 is a fig~re si~ilar to Figure 6, this fi~ure
2 being taken along line 7 - 7 of Figure 5A, and shows the drive
3 1 mechanism for rotation of the outer extruder member.
4 'I FIGURE 8 is a vertical section of the exit portion of
the machine shown in Figure 5B, drawn to a somewhat larger scale.
6 FIGURE 9 is a vertical section taken along line 9 - 9
7 of Figure 8.
8 FIGURE lO is a vertical section taken generally along
9 line lO - 10 of Figure 8.
FIGURE 11 is a vertical section taken generally along
11 line ll - ll of Figure 5B.
12 FIGURE 12 is a vertical section taken along line 12 - 12
13 of Figure 5B.
14 FIGURE 13 is an enlarged showing of the area where the
inner and outer gels meet for rotation and extrusion.
16 FIGURE 14 is a modified form of the stabilizing annulus
17 for the machine.
18 FIGURE 15 is another modification of the stabilizing
I9 annulus which may be used with the machine.
General Description
21 For a general understanding of the invention, reference
22 is made to Figures 1, 2 and 2A.
23 In accordance with this invention, the apparatus includes
24 an inner extruder sub-assembly having an inner mandrel and an
¦ outer extruder sub-assembly having an outer mandrel. Gear means
26 ¦ described subsequently, rotates the inner extruder sub-assembly
27 in one direction (clockwise, as shown in the drawings) and the
28 outer extruder sub-assembly in the opposite direction (counter-
29 clockwise, as shown in the drawings).
The inner gel A is fed to the interior of the apparatus
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1 ¦¦ through an inlet located at the forward end of the machine and
2 !¦ goes through a circular passageway, one wall of which is the inner
3 ¦1 extruder sub-assembly, the other wall of which is a stationary
4 1I tube described subsequently. The outer gel B is fed to the ma-
5 ¦I chine through an inlet and is fed to the outer extruder sub-
6 1¦ assembly. The inner gel A is directed through two sets of a
7 1i plurality of orifices generally radially outwardly and the outer
8 ll gel B is fed through a plurality of orifices generally radially
9 inwardly. Thus, the inner and outer gels are formed into a series
of ropes which later are joined into layers and the collagen fib-
11 rils and/or fibers become oriented in the direction of flow as a
12 result. As shown in Figure 1, the two gels come together near
13 1 the exit of the machine and move for a short distance in the space
14 between the outer and inner extruder sub-assemblies which are
rotating in opposite directions and then between an inner and oute
16 stabilizer which forms a stabilizing annulus. The ropee of the
17 inner and outer gels are thus directed in a generally helical
18 direction by the inner and outer counter-rotating extrusion mem-
19 ~ bers. As can be seen in Figuresl and 2A, the product being dis-
charged from between the outer and inner stabilizers consists of a
21 ¦ net-like structure of layers formed from ropes having oppositely
22 ! directed helical orientations. -
23 This helical orientation remains even after the tubular
24 collagen product has been subjected to further treatment which
results in a neutralization of the acid-swollen gel, a removal of
26 I much of its water content, and a hardening of the tubular structur
27 into a casing which is then dried, as can be seen in Figure ?.
28 Figure 2 illustrates the final product showing that the
29 resultant tubular product maintains the helical net-like structur ~-
3o Thus, as can be seen in Figure 2A, the final product cansists of
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1 j a net-like structure of two concentric layers 3 and 5 of oppositel
2 ¦ helically directed hardened ropes. As there shown by the wavy
3 line 7 where the two layers meet, there may be a relatively
4 small amorphous boundary region where the orientation of the
fibrils and/or fibers may be random. At any ratP it is clear
6 that the outer layer consists predominantly of outer gel
7 ropes helically directed in one direction and the inner layer
8 consists predominantly of inner gel ropes helically oriented in
9 the other direction.
As shown in Figure 2, the angle of the helix measured
11 from a line extending along the longitudinal length of the casing
12 is preferably about 35-50 although this angle can be widely
13 varied if desired.
14 Different angles may be desired for maximum casing
strength depending on particular machines with which the casing
16 will ultimately be used in sausage manufacture, since various
17 machines will place different kinds of stress on the casing.
18 Basically, however, as shown in Figures 2 and 2A, the
19 finished product consists of two hardened layers 3 and 5 with each
layer being formed from a plurality of ropes 9 with the ropes
21 of one layer being helically directed in a direction opposite
22 from the ropes in the other layer.
23 After the tubular product is discharged from the extrude~
24 of this invention it is subjected to further treatment such as
set forth in U.S. Patent No. 3,535,125.
26 The final casing thus prepared contains two layers of
27 ropes of collagen which are now in hardened form. The action of
28 the counter-rotating extruders, the effect of the width of the
29 annular passage, which is less than the diameter of the individual -~
ropes making up the layers, and the hardening and drying steps
1113~i'7~
1 used to finish the casing result in the ropes present in the
2 hardened layers no longer retaining their original spaghetti-like
3 appearance. Instead, the ropes are somewhat irregular in cross-
section and have a more flattened appearance and the ropes are
partially merged in the boundary areas with the adjacent rope
6 with one rope overlapping the next. Yet, because of the longi-
7 tudinal orientation of the majority of fibrils and/or fibers on
8 the external surface of the rope, the outline of the ropes remains
9 detectable, particularly when the casing is wet, in the hardened
layers of the casing. Each layer of the casing appears to have
11 a banded effect with the bands being somewhat irregular but
12 roughly parallel and suggestive of the original ropes from which
13 they were prepared. The outer surface of the finished casing is
14 relatively smooth, and does not contain ridges or striations such
as in British Patent No. 1,166,398. Because the orientation which
16 is visible in the hardened ropes forming one layer is in opposed
17 direction to that on the other concentric layer, the tubular
18 structure has a net-like appearance. The structure is not truly
19 a net, however, since there are no holes in the casing walls. The
final casing is a laminate (the two layers of the casing actually
21 can be pulled apart by careful manipulation) and looks like a net.
22 Within each layer, the hardened ropes making up the layer have
23 a banded appearance in which, when the casing is wet, there are
24 alternating lighter and darker areas which enables one to
visualize the original ropes and their boundaries and to see the
26 net-like appearance of the final casing.
27 Thus, it will be appreciated that ropes and layers as
28 ¦ illustrated in Figures 1, 2 and 2A are shown in a somewhat idealize d
29 ¦ condition whereas in actual practice the ropes tend to flatten
out and become merged at their borders.
L3q7b
1 Detailed Description
.
2 Reference is now made to Figure 5A, Figure 5B and
3 Figure 8.
4 - As shown therein there is a stationary housing or frame
6 on which the remaining elements of the extruder mechanism are
6 mounted. Attached to the frame in any convenient fashion is a
7 hollow stationary member 8. The stationary member 8 is hollow so
8 as to accomodate the passage of ammonia gas which is used in
further processing occuring after the tubular collagen is dis-
charged from the apparatus of this invention.
11 The inner stationary member 8 is threaded 10 at one
12 end for receipt of a nut 12. The nut 12 maintains an inner
13 stabilizer member 16 in fixed position on the frame 6 (Fig. 5B).
14 The inner stabilizer 16 is immediately adjacent to an
outer stabilizer 18 forming a stabilizing annulus. As will be
16 ¦ seen, the gel after being extruded between the inner extruder 55 ar d
17 outer extruder 57 passes between the inner and outer stabilizer -
18 as the collagen product is discharged from the extruder mechanism
19 to thereby size the product as it is discharged. The outer stabil-
izer is attached to the housing flange 17 by any convenient means
21 such as screws 20. The space between the inner and outer stabiliz~ r
22 can be varied depending upon the desired size and/or characteristic s
23 of the final product.
24 Located at the opposite or forward end of the extruder
is an inlet 22 through which the inner gel A is fed to the machine
26 (Figure 5A). -
27 Mounted in inner mandrel bearing 24 is the inner mandrel
28 2. The inner mandrel 2 is concentric with ar.dspaced from the
29 hollow stationary member 8 to form a passageway 11 for the inner
gel A. Inner mandrel 2 and inner extruder 55 together form the
37'7~i
1 ~ inner extr~der sub-assembly.
2 In addition to the inner mandrel 2 there is an outer
3 mandrel 4 mounted on outer mandrel bearing 26. The outer mandrel
4 4 is mounted so as to be concentric with respect to the inner
mandrel 2. Outer mandrel 4 together with outer extruder 57
6 form the outer extruder sub-assembly.
7 The outer extruder 57 is spaced from the inner extruder
8 55 forming a passageway for the gels to pass after the inner gel
9 and outer gels are brought together. The width of the passageway
between the inner and outer extruder can vary depending on the
11 desired characteristics of the final product but in one practice
12 was .019 inches. The outer gel is fed to the outer extruder
13 ¦ through inlet 27.
14 In accordance with this invention, means are provided
whereby the inner and outer extruder sub-assemblies are rotated
16 in opposite directions. This means is best shown in Figs. 5A, 6
17 and 7. As embodied there is a drive shaft 28. The drive shaft
18 is rotated by any conventional motor means not shown. The drive
19 shaft 28 is keyed by key means 30 to a relatively wide driving
gear 32.
21 In the case of the inner extruder sub-assembly, the
22 driving gear 32 engages an intermediate gear 34 which in turn
23 engages gear 36 which is attached to the inner mandrel 2 by key
24 means 38 to rotate the inner extruder sub-assembly in a clockwise
direction (see Figs. 1 and 6). On the other hand, driving gear 32
26 engages gear 40 directly which is attached to the outer mandrel 4
27 by key means 42, to rotate the outer extruder sub-assembly in a
28 ¦ counter-clockwise direction. The direction of movement of the
29 inner and outer extruder sub-assembliee is not important so long
as the inner and outer extruder sub-assemblies ro~ate in opposite
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1 ¦ directions.
2 ~ It is not necessary, but is preferable, that the inner
3 j and outer extruder members rotate at about the same speed. The
4 i helical angle of the streams of collagen in each layer of the casir g
5 ¦ can be varied by modifying the relative speed of the counter-
6 rotating extruders and the casing extrusion speed.
7 In accordance with this invention, the inner and outer
extruders 55 and 57 have a plurality of orifices therein to
9 extrude both the inner and outer gels into a plurality of ropes.
It is the extrusion of the collagen gel through the orifices
ll which orients the fibrils and/or fibers in the direction of
12 extrusion at least in the outer surface o the ropes which
13 make-up the layers, which orientation remains even after subsequen
14 treatment. The memory of these ropes and their oriented fibrils
and/or fibers persists in the finished product. The orifices may,
16 therefore, be thought of as memory nozzles.
17 The specific construction is shown in Figures 9 and lO -
1~ and Figure 13.
19 Turning to Figure 9, the outer gel enters through inlet
27 into a first manifold 44, through a series of openings 46 to a
21 second manifold 48 through another series of openings 50 to a
22 third manifold 52. The outer gel then passes, as shown by the
23 arrows, through a series of outer gel orifices 54 in outer
24 extruder 57.
As shown, there are thirty-two such orifices but there
26 can be a greater or lesser number of such orifices, the specific
27 number not being a critical factor. Thus, satisfactory collagen
28 1 casing has been made with sixteen and with twenty-four orifices
29 in the extruder. Possibly even a lesser or greater number of
~ orifices would be satisfactory. In addition, although as illustrat ed
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1S 1377~i
1 in the drawings, each extruder has the same number of orifices,
2 this is not believed to be a requirement. The outer gel by being
3 passed through the outer orifices 54 is formed into a series of
4 ropes which causes the fibrils and/or fibers to become aligned
in the direction of extrusion. The fibrils and/or fibérs will
6 "remember" this alignment despite formation of the ropes into
7 layers and subsequent treatment.
8 The inner gel is extruded through a series of orifices i
9 as can be seen in Figures 9 and 10. Tn the case of the inner gel
the inner extruder 55 has two sets of orifices 56. As shown, the
11 number of orifices is thirty-two as in the case of the outer
12 extruder but the number could be greater or lesser, the number
13 not being a critical factor.
14 The greater the number of orifices, the greater the
number of ropes in the streams in each layer, and the finer the
16 net-like appearance of the finished casing.
17 Because of the relatively small diameter of the inner
18 extrusion member, it was found convenient to use two sets of 16
19 orifices rather than one set of thirty-two. Also, as can be seen
from Figure 13, the sets of orifices are offset rather than in
21 line.
22 Figure 13 which illustrates the ofset orifices 56 also
1 23 shows the use of a manifold 65 for receipt of the gel immediately
24 before the gel passes into the passageway between the inner and
25 outer extruders. -
26 The diameter of the orifices in the inner and outer
27 extruders is relatively small and in one practice of the invention
28 was .062 inches.
29 This distance it will be noted is considerably larger
than the width of the passageway between the outer and inner
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I
1~1377~i
l ~ ext uder. This re~lts, as indic~ted above, in changin~ the shape
2 1 f the ropes somewhat in that they lose their true rope like appear-
3 ¦ ance which they had when being extruded and take on a somewhat
4 ! flattened form. However, for illustrative purposes, the tubular
5 1 product shown at the exit of the machine (Fig. 1) is schematic
6 and shown in a somewhat idealized form.
7 Figures 9 and 10, by way of the arrows, illustrate the
8 path of travel of the inner gel A moving radially outwardly of
9 the inner extrusion member whereas the outer gel B moves radially
inwardly. The outer and inner gels come together in the space
11 between the inner and outer extruders and move together until -
12 ischarged. (See Fig. 5B and Fig. 8). While the two gels are
13 moving together, they, in effect, maintain their separate identity
14 in what has been referred to as layers because of the previous
extrusion forming the inner and outer gels into separate ropes.
16 The product is discharged after passing between station-
17 ary inner 16 and outer 18 stabilizer members. The inner and outer
18 stabilizers are similar to die members and serve to give the
19 resultant product dimensional stability. As indicated, the space
between the inner and outer stabilizers can vary depending on the
21 desired thickness and/or characteristics of the final product.
22 Then the extrudate is subjected to further treatment as described
23 ¦in the prior art and preferably as described in Patent No.
24 3,535,125 which results in forming the hardened layers of ropes
which are in the final product.
26 Figures 14-15 illustrate how the diameter of the end
product can be varied by changingthe path of travel of the gels
28 as they pass between the inner and outer stabilizer. Thus, for
29 example, Figure 14 illustrates the passageway between the inner ¦ '
and outer stabilizer going generally outwardly so as to increase
. :.
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the diameter of the resultant product. Figure 15 illustrates the i
2 ¦ passage between the inner and outer stabilizers going generally ¦ :
3 1 inwardly to thereby reduce the diameter of the resultant product.
4 ¦It will be appreciated that because of the attaching means used
5 ¦ for the inner and outer stabilizing members, described above, it
6 ¦ is a relatively simple matter to change the diameter of the casing
7 1 product.
8 I Figure 11 illustrates another feature of the invention.
9 ¦ There is shown an inlet 60 leading to a cooling passageway 62
10 ¦ which terminates in an exit 64 from which the cooling fluid exits.
11 ¦ The drawings also illustrate various vents and cooling.,lubrication
12 ¦ and/or pressure relief passageways which have been found helpful
13 ¦ in the practice of the invention but are not deemed critical and ..
14 therefore have not been described in detail. ~ :
The following example illustrates the advantages of
16 the present invention as compared to prior art practices as
17 exemplified by the aforementioned Lieberman patent.
18 As used herein, the following terms are defined as
19 follows:
Breakin~ Strength:
21 This is the tension in pounds needed to break the
22 casing when a 2 to 3 foot length of casing is stretched to the
23 breaking pointwith a h~dheld maximum reading strength gauge.
24 Air Burst Pressure:
This is the air pressure required to break a 2-3 foot
26 length of casing inflated with compressed air until it bursts.
27 The pressure required to burst the casing is measured with a :: :
28 maximum reading pressure gauge.
29 Water Burst Pressure: ~
This is the water pressure required to burst a 2-3 ¦ :
. I ~
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!
. . . . :
,,1 I
l ~ 7'7~
l ,
1 foot length of casing filled with water at ambient temperature
2 measured on a maximum reading pressure gauge.
3 Example I
4 ¦ Unlimed hide as used in commercial collagen casing
production was gr~und to 1/4 inch particle size. About 170 Kg.
6 of ground hide was further comminuted in a water slurry through
7 a high-speed rotary cutter, The comminuted slurry (about 500 1.)
8 was mixed with an equal volume of about a 19% cellulose slurry
9 in 0.46% hydrochloric acid. The mixture was homogenized through
a two-stage homogenizing valve operated at a pressure of 1,500
11 psi in each stage. The extrusion mass so formed was held
12 overnight and again homogenized through a two-stage homogenizer
13 operated at 2,000 psi for each stage. After holding 16 to 24
14 hours, the extrusion mass was filtered through a 9 mil and then
a 6 mil wire wound filter and pumped through a single stage
16 homogenizer at a total pressure of 2,500 psi.
17 The gel so made was fed to an extruder such as that
18 described in the prior art (Lieberman U.S. Patent No. 3,122,788).
19 The extruder of the prior art was operated with an impeller
speed of 175 rpm and tubular casing with a flattened width
21 of 43 to 44 mm was extruded at a speed of about 25 fpm. The
22 casing so extruded was received in inflated form on an endless
23 belt and washed, plasticized, dried and shirred as described
24 in Fagan, U.S. Patent No. 3,535,125. Approximately, 0.8 gms./min.
of a 30nia was used on the inside of the casing and 1.6 gms./min.
26 in the exterior chamber to harden the newly extruded casing.
27 The plasticizer consisted of 5.5% glycerin, 1.1% sodium
28 carboxymethylcellulose and 450 ppm of dextrose in water. A
29 ¦thin-coating of mineral oil was applied to the surface after ;~
Idrying and before shirring.
1~L1377~
1 l¦ The same gel fed to the prior art extruder was fed to
2 ',the extruder of this invention and the casing so produced was 1,
3 Iprocessed in the same way. The gel stream was split evenly
4 ll be-ween the two inlets for the inner and outer gel and tubular
5 l¦casing was extruded with a flattened width of 42.5 to 43.5 mm. at
6 ll 25 feet per minute. The counter-rotating extruder members were
7 'leach operated at a speed of 105 r.p.m. in opposite directions. ,
8 ,IThe ammonia flows were 1.2 g/min. both inside and outside of the
g l¦casing. This casing was plasticized in same plasticizer bath and ¦
10 ¦ coated with oil as in the case of the prior art casing.
11 ¦ The casing produced by the extruder of this invention has
12 1 a readily discernable net-like structure formed by the crossing of
13 !¦the helical ropes of the inner and outer layers during extrusion.
14 ¦¦Before hardening with ammonia, this structure was readily visible
15 ¦ to the naked eye. After drying the casing could be examined by
16 j filling with water and observing the casing surface. Under these
17 1 conditions, the net-like structure was again apparent to the naked
18 , eye. In this example, the angle of the helical ropes in each layer
19 ¦ was about 45 relative to the axis of the casing, or about 90 re-
20 ¦ lative to each other.
21 1 Both the prior art casing and the casing of this inventio n
22 1 were then heat cured by heating from room temperature to 85C. over
23 1 a period of 12 hours and then held at 85C for 6 hours. After !
24 ¦ humidification to a moisture content of about 20 to 40% the
1 following physical properties were measured.
26 ~ Prior Art Casin~ Net-Like Casing
27 ¦ Width of Flattened Tube 44,7mm 44.5mm
28 1 Thickness 1.48 mil 1.50 mil
29 ,¦Breaking Strength30.2 lbs 44.2 lbs
30 jlAir Burst Pressure16.7 psi 19.6 psi
31 ¦lWater Burst Pressure8.2 psi 8.7 psi
32 l¦ Sausages of the frankfurter-type were prepared using a Ty! -
33 I¦Linker (Linker Machines, Inc., Newark, New Jersey, Model 140 ACL). ¦
¦* Trademark
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1 Five strands (35 foot length) of each of the stuffed
2 casings were double-tied with the following percentage of breaks
3 for the two test casings:
4 ¦ TEST # 1 -
Sample Prior Art Casin~ Net-Like Ca~
6 #1 0.83% 2.5%
7 #2 1.67% 0%
8 #3 2.5% 0%
9 #4 0.83% 0%
#5 0% 0%
11 In double ty-linking the links are formed by cinching
12 strings ir~to a knot simultaneously at both ends of the link. This
13 action is resisted more successfully by the net-like casing of
14 this invention.
On another day a similar test of more strands from this
16 experiment showed the following percentage of breaks:
17 TEST # 2 -
18 ~ Prior Art Casing Net-Like Casing
19 #1 1.67% 0%
#2 0% 0.83%
21 #3 0.83% 0%
22 #4 1.67% %
23 #5 2.5% 0%
24 Using the novel extruder apparatus and generally
following the aforementioned example but varying slightly the
26 operating conditions and starting materials, a number of different¦
27 net-like collagen casings within the scope of the present inventior
28 were prepared. These proved highly satisfactory for use on high
29 speed sausage-making machinery, such as; the Townsend semiautomatic
1 DB4A stuffer and linker and the fully automatic Townsend model
* Trader ark
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1 ~ DB2A. Prior art casings made from substantially identical collagen I
2 1 formulations and under substantially identical conditions, except
3 1 using the prior art extruders, resulted in excessive breakage
4 1 when used with such high speed machinery and wer~ considered to
have failed badly on such equipment.
6 This invention, in its broader aspects, is not limited
7 to the specific steps, procedures and elements shown and described
8 ut departures can be made therefrom within the scope of the
9 accompanying claims without departing from the principles of the
invention and without sacrificing its chief advantages.
11 This application is a division of Canadian Patent
App icat on Serial No. 2-3,892 f 1 -1 J~ruar 1~, 1976.
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