Note: Descriptions are shown in the official language in which they were submitted.
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VACUUM WR~pPE~ SHIRRED SAUSAGE
.: CASINGS AND THE METHOD FOR MAKING SAME
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. 1 DESCRIPTION OF THE PRIOR ART
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Artificial sausage casings generally are prepared as hol-
low, thin-walled tubes of very grea-t leng-th. For convenience in
handling, these casings are shirred from lengths ranging from about
40 - 160 feet or more to a shirred and compressed length oE the
order of a few inches.
In the preparation and use of artificial sausage casings,
particularly those casings formed from regenerated cellulose, the
reyulation oE ~oisture conten-t in the casing is of ex-treme import-
ance. When the regenerated cellulose casings are first formed,
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they are dried to a relatively low water content, e.g., from about
8 - 10%. Lf the wacer content varies outs:ide this range, damage
oEten results to the casing during the shirring o~eration either
as the result o brittleness in the casing or because of a stick-
ing oE the casing to the shirring mandrel.
After the casing is shirred or during shirring, the moisture
content of the casing is raised to about 14 - 20~, for shipment to
meat packing houses`. At the packing houses, the individual shirred
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` strands are placed on a stuffing horn and meat emulsion is extruded -
to fill the casing to its fully extended length. In high speed
stuffing apparatus, this takes place within a few seconds so that
the casing is extended from a shirred length of from about 8 - 27
inches to an e~tended length of abou-t 40 - 160 feet in length. In
general, an average moistuxe content of from about 14 - 20~ in the
regenerated cellulose shirred casing is req-lired for satisactory
stufing. If the moisture content of the casing is substantially
below about 14~, e.g., 10~, then the casing may be brittle and
result in excessive breakage. On the other hand, i-f the moisture
content exceeds about 20~o ~ -the casing usually is over plasticized
and may overstuE~.
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In the usual course of events, shirred artificial sausage
casings are packaged in cardboard or plastic containers. Several
objectives of the package are desired. One is that when the saus-
age casing is properly humidified, i.e., humidified so that the
moisture content of the casing is from about 14 - 20%, the package
permits retention of this water in the casing during storage.
Secondly, the package should restrict longitudinal movement or
creeping of the shirred artiEicial casing.
A common package for artificial sausage casings is a card-
board box employing end panels having a plurality of apertures
therein for permitting humidification of the casing while in the
cardboard package. These cardboard boxes are commonly re~erred to
in the art dS "caddies". The caddies serve a two-~old purpose in
that they permit humdification of the casing aEter it is shirred
and they restraLnlongitudinal movement of the shirred casing dur-
ing storage.
Various adaptations have been made with the caddy and one
includes the use of absorbent paper liners or separating the
shirred artificial sausage casings in layers. These liners typical-
ly are moistened with water in order to equilibrate the casings with
moisture during storage. The caddies then are wrapped with a
moisture impervious material and sealed to insure that the moisture
is not lost during storage.
A more recent package for artificial sausage casings includes
a heat shrinkable film. In packaging, the shirred casing is placed
within a shrinkable tubular film and then the film is caused to
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shrink about the shirred casing. The ends are secured by clamps
to restrict the longitudinal expansion of the casing.
~ Several disadvantages were noted with the "caddy" packaging
; 30 techniques ~or artificial sausage casings. The cardboard boxes ~ar
caddies were expensive. Secondr the casings often were not proper- I
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ly or uniformly humdifiedO Air circulation, particularly with
shirred casings haveing end closures, often tended to be poor. The
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`'iners used to aid in humidification tended to create a handling
and disposal problem for the meat packer and the casings, often
because of longitudinal expansion, became wedged in the caddy and
were difficult to remove without damage.
Disadvantages also were noted in the packaging of shirred
; artificial sausage casings with a shrinkable tubing. One of the
; problems centered about the fact that the shrinkable tubing had a
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tendency to pull the casings together in a rounded manner and
effected a flattening of the ends o the casing. Also, the tens-
ion was non-uniform and when applied to the casing effected a
bowing of the shirred casing sticks when the sticks were not in
proper alignment. Further, moisture, when added to the package,
tended to flow into the bore of the casing and this sometimes
interered with the coatings applied to the interior oE the casing.
SUMM~R~ O~ THE INVENTION
In accordance with this invention, there is shown a method
for packaging an artificial sausage casing or plurality thereof
for reducing lateral and longitudinal expansion and to protect
; against moisture loss and the resulting product. The method com-
20 prises enveloping a casing or plurality thereof within at least ;~
one flexible film which is substantially impermeable to gas, e.g.
air and water vapor ~a transmission rate for air of less than about
1 cc/100 in. /24 hour-atm.~, removing sufficient air from within
the resulting envelope for producing a partial vacuum therein (an
absolute pressure of substantially not less than 0.4 atm.), and
sealing said envelope for maintaining said partial vacuum. The
evacuation of the envelope cause the flexible film to nestle about
;~the casing or plurality thereof, to provide substantially equal
forces perpendicular to the longitudinal axis of the casing or
plurality thereof, and to effect a seal along the ends of the
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casing to prevent a substantial proportion of moisture rom passing
into the bore of the casing.
Advantages of the instant package include: a package which
~-fits snugly about the casing along its longitudinal surface and
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against the ends to restrict longitudinal expansion; a package
which prevents moisture loss from the casing during storage; a
package which conforms to the casing surfaces from end to end ~
even where there may be a size differential; a package which exerts ~-
substantially uniform pressures on the casing even where environ-
mental disturbances cause slight contraction or expansion of the
casings; a package which reduces flattening of the casings; a
package which reduces bowing of the casing sticks; a pack age
which nestles about the edges and ends of the casings to effect a
-~ 10 seal and prevent substantial moisture leakage into the interior
of the casings; and a package which permits easy removal of casings
from shipping containers and prevents such casings from beco~ing
wedged in such containe~s.
THE DRAWINGS
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Fig. 1 is an oblique view of a shirred artiEicial sausage
casing packaged within a flexible film.
s Fig. 2 is an oblique view of a plurality of shirred artificial
sausage casings packaged within a flexible film which is substantial-
ly impermeable to air.
Fig. 3 is a cross sectional view of Line 3-3 of Fig. 2 show-
ing the flexible film seating along the ends of the shirred casings
.. . . .. .
and penetrating inwardly into the bore of the shirred casing for
restricting longitudinal expansion.
Fig. 4 is an oblique view of tWQ artificiaI shirred sausage
casings packaged within a flexible film provided with a tear strip
~ for easy removal of the film from the casings.
; Fig. 5 is an ènd view of casings arranged in the flexible
film.
Fig. 6 is an end view of another arrangement of shirred
arti~icial sausage casings vacuum packaged in a flexible film.
Fig. 7 is an oblique view of casings packaged as a strip in
side by side relationship.
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Fig. 8 is a frontal view of an apparatus for packaging
casing within a flexible film showing a means for evacuating the
space between the film and casings and means for sealing the film.
: DESCRIPTION OF TEE PREFERRED EMBODIMENTS
.. . ... . .. ..
The artificial sausage casings which can be packaged in a
flexible film in the manner contemplated by this invention are those
o~ regenerated cellulose, polyvinyl alcohol, collayen, alginates,
amylose, and microporous themoplastic films. In a preferred embodi-
ment, however, the artificial sausage casing is of regenerated
cellulose type including both the fibrous or non-Eibrous casing.
The non-fibrous casings lend themselves more to this type o~ pack-
aging than the fibrous casings because the latter cJenerally have to
be soaked in water prior to stu~ing whereas the non-eibrous are
only slightly humidi~iecl. The non-f:ibrous casings typically have
a shirred diameter ranging from about 1/2 to 1 1/2 inches with a
wall thickness ranging from about 0.0005 to about 0.005 inches.
These non-fibrous casings prior to packaging are humidified by con-
ventional means such as by spraying with a moisture providing liquid
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at the time of shirring, e.g., through spray nozzles at the shirr-
iny mandrel or by humidification in an appropriately conditioned
room. The casings may also be humdified during paclcaging as sub-
se~uently described.
The flexible film for packaging the shirred casings is sub-
s-tantially impervious to gas for permitting removal of gas, e.g.,
air, within the envelope formed by the enveloping of the casings
within a flexible film. By substantially impervious to gas, i.e. air
or water vapor, it is meant that the film has a vapor transmission
rate of less than about 1 cc/100 in 2/24 hour/atm. It is understand-
able that if the flexible film were not impervious to air it would
be practially impossible to remove -the gas from the envelope carry-
ing the artificial sausage casings, maintain a partial vacuum therein,
and to prevent against moisture loss.
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Films which are flexible and can be used for packaging
shirred artificial sausage casing include the polyolefins such as
polypropylene, polyethylene, polyvinyl chloride, pol~vinylidene
chloride, polyvinyl acetate, polyamides, copolymers of the above
and coated films and laminates. Virtually any of the films accept-
able for packaging o ood which have the above qualities, e.g.,
impervious to water and air, can be used for packagin~ the shirred
artificial sausage casings. Some, and particularly the laminates,
have the added benefit that they are impervious to vapor and heat
sealable. A nylon-polyvinylidene chlo~ide (saran) or polyethylene-
saran laminate has these properties and thus is advantageous for
packaging shirred casings.
In packaging an ar~iicial sausage cas~ng or pluralit~ thereo,
the casings are en~eloped in at least one flexible ilm. In one
aspect the envelope can be formed by first forming a tube with one
j end and the sides sealed and then placing the artificial sausage
casings in the resulting tubular film. The open end of the tubular
film then can be attached to a vacuum source and the tubular film
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evacuated and sealed while maintaining a partial vacuum inside the
~- 20 tubular film. In another aspect, a pluralit~ of casings can be
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disposed between two films, e.g. one film ply on the top and one
film ply on the bottom. The casings including the film plies are
placed in a vacuum chamber and a vacuum placed in the chamber.
When a desired degree of evacuation in the chamber has been attained,
the film plies are sealed to each o~her along the ends and edges
to orm a completely sealed package. The vacuum chamber then is
vent~ed and as the pressure in the chamber returns to atmospheric
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pressure, the external air pressure causes the film to nestle Z
about the casing surface and the ends. The resulting packages
30 formed by these techniques are illustrated in the drawings to be
described below.
In reference to the drawings, Fig. 1 is an oblique view of
a shirred artificial sausage casing 3 having a plurality of shirring Z
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4 enclosed in a flexible film 5. In forming a packaged single -.
shirredsausage casing, the casing 3 is placed inside of a flexible ~:
film formed into a tubular shape and the air space between the
tubular shaped film and the casing evacuated suEficiently to pull
.. the film about the shirred casing. The tubular film then is sealed
at the end while under vacuum.
Fig. 2 is an oblique ~iew of a packaging arrangement for
shirred artificial sausage casings which is particularly adapted
for this invention. The shirred asuage casings 21, 22, and 23 are
arranged in a nested manner in such a way that a portion of the
external surace of one casing is in contact with the surEace oE
casi~gs disposed about it. In viewing an arrangement of the three
artificial sausage casings within this packaging a~rangement, one
will form a triangle which ie not a right ~riang~e iE the center
lines A, B, and C of the respective casings are connected by
straight lines. Where these casings are oE the same size, as gen-
erally is the case where shirred casings are packaged, the triangle
formed is an equilateral triangle. In packaging casings in this
arrangement, the tubular sausage casings 21, 22, and 23 are ar-
ranged as shown and then placed in a flexible film 24 and sealedin this instance by heat sealing means to form a heat sealed seam 26.
In viewing the packaging arrangement along the Line 3-3 as shown
: in Fig. 3 one can observe the inward displacement of the flexible
film 24 into the respective ends of casings ]1 and 23, namely, 28,
:~ 29, 30, and 31. This inward displacement of the Eilm caused by
the evacuation o:E the air space between the flexible film and the
sausage c~sings provides a seal about the edges o:E the casings to
prevent substnatial moisture from penetrating into the bore oE the
casing which may in efect wash o:EE or leach a lubricant applied to
the interior of the bore to enhance peelability of the casing.
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Fig. 4 is an oblique view of another packaging arrangement
for artificial sausage casings wherein casings 41 and 42 having a
plurality of shirring pleats 43 are enclosed in a tubular film, e.g.,
polyethylene, with the air space evacuated and the film sealed.
To enhance the ability of an operator to remove the enclosed film
from the artificial sausage casings process therein, a tear strip
45 is provided along the external surface of the tubular film.
This tear strip can be employed in other types of packaging films
as desired.
Fig. 5 is an end view of a package of 50 sausage casings
encompai3sed within a flexible film. The arrangement is similar to
that nested arrangement shown in Fig. 2, i.e., casings 62, 63, and
64, which are arranged so that the cenker line~ G, ~ & J when con-
i~ nected by straight lines Eorm an equi.lateral triangle. In Eorming
j the package, the shirred sausage casings are enveloped in tubular
shaped film 65 and held by cartridge 61. The air space ~etween
the tubular film 65 and sausage casings as represented by casings
62, 63, and 64 is evacuated to a desired level and the film sealed
about the casings. Cartridge 61 usually is removed from the pack-
aged casings and the package placed into a shipping container.
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Fig. 6 is an end view of a packaging arrangement now employed
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in the marketing of artificial sausage casings. This arrangement
is different than that shown in Figs. 2 and 5 in that the casings
as represented by 82, 83, and 84 are placed in side-by-side relation-
ship in roews o ten and five deep in the package to make a total of
50 for the complete package. The casings are separated by porous
liners 86 which are first moistened with water so that the liners
can equilibrate with the artificial sausage casinys in order to
provide the desired proportion of moisture. In viewing an arrange-
ment of three sausage casings, namely, 82, 83, and 84 which are
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disposed side-by-side, the centers D, E, and F when connected by
straight lines form a right triangle as opposed to an equilateral
triangle as shown in Fig. 5. In forming the package, -the five
rows of ten casings are enveloped in flexible film 85 and held in
place by box 8l. The air in the envelope is remo~ed for producing
a partial vacuum therein and the film sealed for maintaining the
partial vacuum. The resulting casings then are removed from box 81
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. and placed in a shipping container for sale.
Fig. 7 is an oblique view of another arrangement which can
be adapted for the packaging of arti~icial sausage casings. In
; the manu~acture of khis type package, it is convenient to envelop
representative casings 101, 102~ and :L03 between flexible film
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plies lO4 and 105. Th~s assembly of casings and flexible plies is
placed in a vacuum chamber. The chamber is evacuated to a desired
pressu~e, e.g., 0.5 to 0.9 atmospheres/ and while the chamber is at
such pressure, causing the plies to be sealed together at ends 106
, . .
and 107 and along the edges (not numbered). After the casings are
completely sealed between the two film plies 104 and 105, the
vacuum chamber is vented to the atmosphere. The external air
pressure causes the film to conform to the casing as shown and to
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restrict longitudinal movement o~ such casing while in the package.
To illustrate a me~hod for packaging a plurality of shirred
artificial sausage casings (cellulose or collagen) within an air
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impermeable film, reference is made to Fig. 8. In Fig. 8 a flexible
tubular shaped film 141 comprising a laminate of saran and nylon is
sealed across the sides and one end and has a tear strip l54 along
a side and is placed upon kable l42. A plurality of shirred arti-
`~ ficial sausage casings 143 are placed in tubular film l4l in a
configuration as shown in Fig. 5 and held by cartridge 156. In
this arrangement~ the casings are arranged in five rows of six
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casings each separated by four rows of five casings each. Thiscommonly is referred to as hexagonal close packed or nested arrange-
ment. The open end of the tubular film 141 is placed between two
heat sealing bars, 144 and 145. These bars are used to secure the
tubular film 141 to itself by means of heat after the air space be-
tween the tubular film 141 and casings 143 is evacuated. The open
end of the tubular film 141 is threaded through and between the heat
sealing bars 144 and 145. Vacuum source 146 is inserted into the
open end of the tubular film 141. The open end o the tubular film
141 then is secured to the vaccum source 146 to prevent air leakage
and permit evacuation oE the air space between the tubular film 141
and arti~icial sausage casings 1~3.
~uring evacuatlon, vacuum source 146 normall~ w:ithdrawn ¦ `
beyond heat sealable bars 145 and 146. On the other hand, there
are commercial vacuum packaging apparatus which permit the vacuum
source to extend beyond the heat sealing bars during evacuation. In
that type of apparatus, however, the vacuum source is moved to a , `
point in back of the heat sealing bars during the heat sealing
operation so that the vacuum source is not trapped. On disadvantage
with this type of apparatus often is that so~e of the vacuum in the
air space between the tubular film and artificial sausage casings
is lost as the vacuum source is moved to a point in back of the
sealing bars.
In some operations and prior to the achievement of a desired
level of evacuation of the air space between the tubular film and
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; casings, a predtermined amout of moisture is introduced into the
package. Often this is introduced by rod 147 being placed into
the annulas (not shown) but is particularly shown in Fig. 2 as 25.
The moisture content of the artiEicial sausage casings for regenerated`
3Q cellulose generaliy should be between 14 and 20~ and can be provided
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by the addition of a moisture providing liquid, e.g. r water,
glycerin, or mixture thereof. The technique oE evacuating the
air space betweer~: the tubular film 141 and artificial sausage
casings 143 prior to introduction of moisture preven-ts substantial
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moisture from entering into the bore of the artificial sausage
casings by flowing around the ends oE the casings. On the other
hand, because the external surface of the casings are not smooth
primarily because of pleats 4 as shown in Fig. 1, the liquid will
flow along the external surface of the casings into voids to ef-
fectuate an overall moistening or humidification of the casings.It should be noted that other additivies ~lavorants) to the cas-
ing can be added through rod 147 or the casing can be ~lushed with
~n inert gas before vacuum is app~lied.
~ fter the proper proportion oE moisture has been added to
the casings, rod 147 is pulled back to a point behind the heat seal-
'"' ! ing bars 144 and 145. Continuous evacuation of the air space is
maintained to provide an absolute pressure in the air space not
substantially less than about 0.4 atm. In most instances, the
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absolute pressure in the air space between the tubular film and
artificial sausage casings is caused to be be~tween about 0.5 - 0.9
atm. and preferably between about 0.6 - 0.75 atm. As might be
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~ expected as the absolute pressure in the alr space is reduced, i.e.,
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substantially below about 0.4 atm., the pressures placed upon the
surface of the artificial sausage casing, while in their arranged
condition, can cause flattening of the casings. This flattening
of the casing particularly at the encls may make then unaccpetable
for high speed automatic stuffing machines. If the absolute press-
ure in the air space is above about 0.9 atm. then usually there is
~ not suEEicient restraint to prevent longitudinal expansion of the
1 30 casing or sealing of the film about the ends. Experience has shown
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that absolute pressures of about 0.6 - 0.75 atm. provides ade- I :
- quate sealing to effect protection of the artificial sausage
casings packaged in the tubular film and prevent longitudinal 1 :
expansion and yet does not effect a flattening of the casing wall
or end.
After the air space has been evacuated to the desired absolute ¦
pressure, sealing bar 144 which is supported by members 148 and
150 is caused to move downwardly by pneumatic cylinders 149 and ¦ .
: 151 thereby bringing the sealing bar substantially in contact with I ;
the sealing bar 145 which is supported by Table 142. (Support
member 150 and pneumatic cylinder 151 are hidden by member 1~8 and
cylinder 149, respectively, and, there~ore, shown by dotted line.)
Once these sealing bars are p.res~ed toyether, heat :i~ applled to
e~ect heat sealing o~ the laminate. AEter the open end oE the
tubular film is secured by heat sealing, sealing bar 144 is moved
l upwardly by appropriate movement of cylinders 149 and 151 and the ~ .
i package is removed.
Tha resultant package maintains the pre-arranged alignment :
.. of the artificial sausage casings and provides a desirable package
for maintaining proper moisture in the casings during an extended
.`; period of storage. Further, the substantially equal forces which
are applied uniformly along the casing wall tend to reduce longi-
tudinal expansion of the casing during storage and reduce the tend-
ency of bowing.
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