CA1195544A - Cored high density shirred casings - Google Patents

Abstract

CORED HIGH DENSITY SHIRRED CASINGS

ABSTRACT OF THE DISCLOSURE

Flexible tubular cellulosic food casing shirred and compressed onto a rigid hollow tubular core to a high compaction condition to produce a casing stick with additional stuffing length capacity, enhanced structural stability and strength, and larger stuffing horn adaptability.

Description

COR~D HIGH DENSI:rY SHIRRED CASINGS
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INTRODUCTI ON
Thi~ invention rela~e~ ~o cellulosic fQod 10 casings, more particuïarly to shirxed ~ellulosic ~ood c:asings compactedly mounte~ on rigid hollow ~ubular core~
to a high compaction condition to produl:e shirred casing sticks which have ~i~nificarltly addi~io~al ~u~fable length t improved ~t:i:uc~ux31 ~ability and ~txeng th, and 15 the added featur~ o~ rendering casing~ presently commex cially available i~ givea~ ~iz~s adap~able ~or utiliza~ion ¢n la~ger bore ~uffing horns ~:han heretofor~ po~ible.
The invention is parkicularly useful in the production t~f ~hirred casing ~ick artlcl~s used in ~he foo~ industry 20 ~or the m~r,ufacture ~f ~au~age products of all si2e5, arld it al~o find~ ~ign~ icant advantages :Eor u~e in ~h~

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stuffing into casing lenyths of chunk form food produc~s such as whole boned meat articles.
TYPES OF CASINGS
. Artiflcial food ca~ings used throughout the world in processing a great variety of meat and other food products, such as sausages of various types, chee~e rolls, turkey rolls, and the like are customarily pre-pared rom r~generated cellulose and other cellulosic materlals~ Casing~ are of several dif ferent types and sizes to accommodate the different categori~s o food product to be prepaxed and are provided in supported or unsupported form, the supported casinys, commonly re~
erred to as "fibrous casings", having a fibrous support web embedded in the casing wall.
~ common feature of many processed food products, particularly meat products, is that the mixture of come-stible ingredients, commonly called an "emulsion", is stuffed into a casing under pressure and processing of the ood product is carried out after i~s encasement.
The food product may also be stored and shipped while encased in the casing, although in many instances, and particularly with small sausage products such as frank-furters, the casing i~ removed from the food product after comple~ion of the proces~ing.
The designation "small ~ood casings" re~ers yenerally to those casings employed in the preparation o~ small size sausage pxoducts such as frankfurters. As the name suggests, this type of food casing is small in . ~ . ~. .. .

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stuffed dlameter, generally having an :inflated diameter within the range of from about 13 mm to about 40 mm, and is most usually supplied as unsupported thin-walled tubes of very great length. For convenience in handling, thes~ casings, whlch may be 20 to 50 meters in length or even longer, axe shirred and compressed to produce what is commonly referred to as "shirred casing sticks" of from about 20 cm to about 60 cm in length. Shirring machines and the products thereof are shown in U. S.
Patent Nos. 2,983,949 and 2,984,574 among others.
"Large size food casings", the common designation for casings used in the preparation of gener~lly larger food products, such a9 salami and boloyna sausages, meat loaves, cooked and smoked ham butts and the like, are pro-duced in stuffed diameter sizes of from about 40 mm toabout 200 mm or even larger. In general, such casings have a wall thickness about threa times greater than "small size casings" wall thickness and are provided with a fibrous web reinforcement embedded in the wall, although they may be prepared without such supporting medium. For many years the large size tubular casings have been supplied to the food processor in flattened condition, cut to predetermined lengths of from about 0.6 to abou~

2.2 m. More recently, however, but prior to the time of this invention, large si~e casings of both the fibrous and the unsupported types have been and are being supplied in the form of shirred 5ticks contain.ing up to about 65 m . .
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of casings for stuffing with high speed apparatus.
CASING MOISTURE CONTENI' In the preparation and use of artificial food casings, control of the mois~ure content of the casings is of importance. While the sh:irred cellulosic casing sticks of the type used in this invention should have a moi~tuxe content of at least about 13~ of total casing weight, the moisture level may be higherO
When small size regenerated cellulose casings are produced, it is generally-preferred that they have a water content in the range of about 14~ to about 18% by weight of total ca~ing to enable stufing operations to be carried out without damage to the casings~ This relatively narrow range of moisture content is also im-portant because excessive breakage of the casing duringstuffing has been found to occur at lower moisture con-tent~, and greater moisture content results in excessive pla~ticity of the casing material and consequent ovarstu~fing. - -2~ The large-size casings as described hereinabove have recently been improved to the extent that shirred and compacte.d casing lengths are available in premoistur-iæed:condi~ .sQ ~hat the long used and troublesome step of soaking such casings immediately.prior to the s~uffing operation has now been eliminated. The moisture contents of the larger size casings of the fibrous rein-forced variety, when they are furnished in shirred and premoist~rized condition, are usually found to be in the . . ~

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range of from about 16~ t~ about 35% moisture by total casing weight~
The specific moisture content may be selected to accommodate the requirements or preferences of the user. If the moisture content is high and a long storage period is contemplated before stuffing, steps to prevent mold or bacterial growth are advisable~ One approach consistent with the invention is to limit the activity of the water added prior to or during stuffing wi~h sufficient amounts of such solutes as propylene glycol or glycerine. These also usefully function in casings to be shirred and compacted as plasticizers or humectants.

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THE SHIRRING PROCESS
Shirring techniques for the casings described hereinabove in accordance with patent references noted, as well as with others, can be generally described as involving the continuous feeding of a length of flat casing eed stock, from a reel for instance, into a shirring machine where it is inflated with low pressure gas, usually air. The inflated casing is pa~sed through an arra~ of shirring rolls which pleat the casing up against a restraint on or a~out the shirring mandrel until a preselected shirred length has been attained.
For a floating mandrel type of shirring machine, such as described in USP 3,766,603 for example, the shirred casing is then transferxed linearly past or away from 15 the restraint against which the shirring was per~ormed and onto an extended mandrel portion whereon it is compacted into a desired stick length. For a with-drawing mandrel shirring machine such as de~cribed in USP 2,583,654 for example, thP hirring mandrel with the shirred casing remaining thereon is rotated to an alter-nate position where the shirred casing is compacted to the desired stick length.
The normal compaction results in a stick length which may be from about 1.0 percen~ to about 1.2 or 1.3 percent of the original casing length.
The United States patent to ~ewitt, U. S. 2,001,461, for instance, describes how an original casing length of 396 inches (1006 cm) is reduced to a length o~ less than four inches (10 cm) in stick form. Hewitt further speculates . .

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that the lowes-t practical limit probably attainable with regard to the ratio of stlck length to original casing length is probably in the neighborhood of one one hundred thirtieth, (1/130). However, EIewitt fails to recognize the problems encountered when attempting to produce such a highly compac-ted shirred casing stlck, of commercially practical lenyth, and he does not add.ress the importance of bore size.
The ratios of original casing length to shirred stick length have bPen generally in the order of 70 to 100 throughout the indus~r~, prior to the time of the present invention. This ratio is referred to as the "pack ratio"
and is the reciprocal of the ratio discussed by Hewitt.
Packing efficiency is another way of quantita-tively expressing the extent to which original casing length~ are compacted in the shirred stick form~ Packing efficiency is defined as the ratio of the volume of the shirred and compacted casing in a unit length divided by the volume of the same unit length which would be occupied by solid casing material, and it may be determined by the following relationship:

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LC X ( 2 x FW x tC ) PE =
4 (oD2 - ID2) x Ls where PE = Packing Efficiency Lc = casing length L5 = shirred casing stick length FW = casing flat width tc ~ casing wall thickness OD = shirred casing stick outer diametex ID = shirred casing stick inner diameter This computation automatically ta]ces into account the specific gravity, and/ur density of the casing material it~eli. Inspection of the relationship shows that the ratio is actually the volume of the casing flat stock which is contained in the shirred casing s~ick, divided by the volume of a hollo~ cylinder having the same dimensions as the shirred casing stick~ The extent to which packing efficiency increases i5 thus measured by the closeness of its approach to~ards one (1), unity.
Since pack ra~io is the ratio of Lc to Ls, another way to express the packing efficiency relation-ship is as follows:
2 x FW x tc PE = (Pack Ratio) _ _ 2 - ID2) It can be seen that for a given packing effi-ciency, the pack ratio varies with the difference between the outside diameter and the inside diameter of the stick of a given slze casing. Further, since the outside dia~
1~155-2 meter i5 necessarily limi-ted by the flat width (FW) of the casing used to form the stick, increasing the diameter difference to increase the pack ratio must decrease ulti~
mately the size of the bore or inside diameter. While S the objectives of maximum stick bore and maximum pack ratio work against each other, the fact remains that packing efflciency is maximi2ecl at a given pack ratio when the ~tick inside diameter is maximized.
It is usually desirable to utilize the maximum bore size (internal cross sectional area) stuffing horn wi~h a given casing size, in part to maximize throughput and minimize stuffing pressure. Another reason to maximi~e the horn siæe is to eliminate the danger of "fatting out". Fatting out is a phenomenon which axises when the passage of the meat emulsion through a s~uffing horn at a hiyh shear rate causes the emulsion to break down and allows water and fat to separate out. The water and fat thereafter accumulate between the surface of the inished sausage produ~t and the cellulosic food casing during processing, to thereby produce an unsatis-factory sausage product having an unacceptable visual appearance. The shear rate decreases with increasing stuffing horn inner diameter.
The goals that have been sought in shirring ~5 technology have been to produce a casing stick which can be deshirred and stuffed on a stuffing apparatusV continuously, with no mechanical deects or breakdowns so as to insure contlnuous pro-:~955'~

duction, the stick itself having sufficient structural and mechanical integrity, i.e. coherency, to withstand the ordinary rigors of packaging, storage, handling and placement on the stuffing apparatus, and, in addition, the desideratum of compacting as much tuffable casing into a given stick leng~h as is technically feasible or use on a stuffing horn of maximum possible bore size.
Acc~rdingly, th~ "ideal" casing stick is one of high eoherency, balancing a long length of casing per ~lit stick length (high p~ck ratio) and a large inner diameter or bore size (high pac~ing efficiency).
A typical prior art pack ratio and packing efficiency may he calculated from the teachings of USP

3,528,825 to Doughty. Referring to column 5~ line 75 through column 6, line 5, we find the description of a shirred ca~ing stick in ~hich 95 feet (30 meters) of casing having.an inflated outside diameter of 22/32 inch tl.75 cm) with a wall thickness of 0.001 inch (0.0254 mm) is; shirred into a stick ha~ing an O.D. of 7/8 inch (2 . 22 cm), an I~D. of 1~2 inch (1.27 cm), and a stic-k length of 16-1/4 inches (41~ 28 cm) . Using those data and the above formula for packing efficiency, it will be found that the prior art casing illustrated in Doughty had a packing effic.ienc~ of 0.374. The pack ratio of this prior art casing was 70; 95 feet (30 meters) shirred and compacted to 16-l/4 inches (41.28 cm).
Coherency of a shirred ca~ing stick is deter-mined b~ meas,uring the bending moment in inch-pounds at ~155-2 ~$~5~'~

the breaking of a stick. A casing stick is cradled on two V-notched support brackets secured on a base plate and spaced apart a distance (D) about 80% to 90% of the length of the casing stick being tested. A pressure member having V notched strutc; spaced apart a distance of D less 4 inches i5 central].y lowered onto the top of the casing stick. A downward pressure is provided by manuall~ op~rated handle, rack and pinion linkage to a force yauge (such as Hunter Force Indicator, Model L-IM
wlth a "Hold at Maximum Devicel') that is secured centrally to the pressure membex. The force is increasingly applied until the casing stick breaks. The force reading P in pounds is noted. The bending moment in inch pounds at break on the apparatus is equal to P/2 x 2 inches, and thus the force reading P equates to inch-pounds of bending moment to break the casing stick. In general, a coherency of at lea~t about 1.2 inch-pound is required and a coherency of at least about 2.5 inch-pounds is especiall~ suitable and preferred.
Sinc~ the relationship of usuable casing stick bore diameter with respect to stuffing horn diameter is a most meaningful measure of casing article functionalit~, a "drop fit" test has been developed for use with shirred casing articles. To simulate the placing of a shirred stick on a s~uffing horn and thereby measure the effective internal diameter of the shirred stick, a test was designed wherein a shirred stick is-placed over the upper end of a vertical stainless stèel rod of longer length . .

~ 12-than the shirred stic}c and allowed to freely fall under its own weight completely around said rod to its lower end. More particularly, the rod may be vertically positioned on a table. The shirred stick is placed over the rod upper end and then released. If the stick falls to the table surface, the drop fit test is successful.
Rods are available in diameter increments of 0.010 inches, and for certain casing size ranges, rods have been fabri-cated in 0.002 inch increments. The shirred stick is tested on each rod beginning with the smallest rod and on each succeeding size rod until the shirred stick will not freely fall over the entire length of the rod. The largest diameter rod over which the stick freely falls for its entire length is the effective internal diameter of said shirred stick~ i.e.l the "drop fit" diameter.
In the manufacture of shirred cellulosic casing sticks, the individu~l sticks vary slightly in bore size, in part due to irregularities in extensions of pleats within the stick bore. Por this reason, for experimental work, i~ is necessary that mul~iple s~irred sticks, e.g. f at least about 10; be measured for drop fit and the arithmetic average used to determine functionality of the entire group in terms of the stuffing horn fit. As previously indicated, drop fit averages are preferably to the thousandth of an inch, and a drop fit require-ment is defined to this degree of accuracy. For example, i the requirement is 0.490 inch minimum, an 5~4~

average drop fit of 0.489 inch would be unacceptable, since a significant number of sticks in ~he group repre-sented by the 0.489 inch average drop fit measurement would not be functional on a 0.490 inch diameter stuffing horn.
One of the most important factors in the shirring of small size food casing is the quality of coherency, i.e. the duxability of the shirred stick as a self-sustaining article. Stick coherency is especially important in efecting the suitability of such sticks for use with automatic food stuffing equipment, as, for example, the machinery employed in the preparation of products such as frankfurters and other similar food articles. A disjoinder or break in a shirred stick prior to mountln~ it on a stuffing horn makes the stick unsuitable for use on such automatic stuffing equipment.
Accordingly, any treatment of the tubular food casing which may be formed into a shirred casing stick must not detrimentally affect the stick coherency, and furthermore, should be directed more toward5 enhancing it.
Signi~icant effort in recent years has been expended in the casing industry, particularly for the small size casings, to develop systems for producing highly coherent casing sticks. These have included chemical treatments as disclosed, for example, in U.S.
Patent 4,137,947, among others.
Conventional shirring on modern shirring machines produces shirred casing sticks with a discernible angular . ''' ' ""' ' ' ' .

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displacement between a plane normal to the longitudinal axis o the stick and a plane in which a shirred pleat lies. This is called the pleat angle. A conventional shirred stick without the core element of this invention, having a plea~ angle of this nature, has a coherency and structural integrit~ which is significantly greater than that of a stack of the same type which has been shirred with the pleat normal to the longitudinal axis of the stick, since the overall stick length is somewhat like a stack of interconnected nesting cones.
We have discovered, particularly or the smaller sizP casings used to make rankfurter type products, that when a conventional shirred stick (uncored) is highly compacted in an effort to maximize its pack ratio, the coh~rency or structural integrit~ of the compressed stick deteriorates to a point whereby the stick is rendered nonfunctional~ That is, the stick is rendered fragile, i5 easily broken, and therefore cannot be mounted on a stuffing horn. It is speculated that this effect occurs when the high longitudinal compressive forces tend to flatten out the "nesting cone" geometxy produced during the shirring process.
We have also discovered that when tubular casing is subjected to the shirring process (i.e. transformed from a flattened tubular form to a folded and compacted stick form as previo~sly described), high inward radial orces are ~eveloped within the resulting shirred stick .

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when high packing efficiencies are achieved. The magnitude of these high forces was not recognized until shirred casing sticks were highly compacted on tubular core elements of the present invention and it was found that substantially rigid cores would lose some core diameter with time. It W3S previously known that the inner diameter o conventional shirred sticks (without a tubular core) show a sharp reduction upon doffing (rPmoval) from the shirring mandrel immediately after compaction, and a more gradual additlonal reduction which appears to continue for about one week or more after doffing, but the magnitude of the forces causing such diameter loss was not recognized prior to the invention.
We have further discovered that the magnitude of these radial inward forces is proportional to the longitudinal compacting force used to compress the stick to the initial compressed length which the stick has just prior to doffing. That is~ the radial inward forces increase when the longitudinal compacting force increasesO
~0 USE OF CORES
British Patent 1,167,377 discloses a stick of shirred tubular casing supported on a hollow former (core) which is shaped and dimensioned for engagement around a stuffing horn. The patentee describes a frictional fit within the stick to restrain it from decompression or sliding off the former.~ It is stated that the former may be made of any desired material, for example, synthetic . .

plastics material or thin cardboard. Accordin~ to the one specifically described former embodiment, it is con structed of polyvinyl chloride extruded to form a cylinder of approxlmately 0.01 inch wall thickness. The article of this patent has been commerciaLized in the form of poly-vinylidene chloride plastic tubular sh~eting shirred on a cellulos2 acetate core of 0~984 inch inside diameter and about 0.0115 inch wall thickness. The invention of the British P ten~ has never been used with shirred cellulosic tubular casing.
In addition to the above usage, the use of a hollow core or central tube as a carrier for shirred large casing has been known for many years. All known previous applications of the core concept to shirred cellulosic casi~gs, however, have been to provide integrity and growth restraint during soaking. Rods were used with small casing for shipping and handling prior to the development of coherent casing sticks. The shirred casing was slid off of the rods onto stuffing horns for use.
In recent years the cellulosic food casing art has moved awa~ from the use of internal tubes for casing restraint, and support, and toward external restraining and supporting means such as nets and shrinkable or elastic film for intermediate and large size casings.
Small casing is used as coherent sticks with no other support.
A principal object of this invention is to pro-vide a shirred casing stick axticle of high coherency with 13155~2 s~

casing shirred and compressed to a higher pack ratio -than heretoore practically attained in the art, while main-taining an acceptable bore size, as evidenced by a high BaCkins eficiency.
Another object of the present invention is to provide a high coherency shlr:red casing stick article with high pack ratio and high packing efficiency of a generic structure and type which is broadly useful across the entire spectrum of casing sizes and types used in the food industr~.
A further important object o this invention is to provide a high density shirred casing stick article having a pack ratio coupled with a packing efficiency which are both significantly higher than that achievable ~5 in the casing industry to date, while at the same time eliminating all potential problems associated in the prior art with lack o s~ructural integrity or coharency.
Another important object of the present invention is the provision of a cored high density shirred casing stick article with a core which has suitable physical propertie~ to oppose the high inward radial forces devel-oped whan a tubular casing undergoes the shirring process and is subsequently compacted to a high pack ratio.
It is a further object of the invention to provide a mekhod for manufacturing cored high density shirred casi~ng s~ick articles on presently available shirring machinery with only slight, if any, modifica-tions therelo to produce the article according to the . .

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invention .
It is a still further object of the present invention to provide a casing article with a combirlation of a largex bore and higher pack ratio than can be 5 achieved with an uncoxed produc t .
Another important object of the invention is the provision o a cored high den~ity shirred casing article, ~hrough which speciic standard casing sizes over all casing si~e ranges, will be enabled to fit onto respectively larger stuffing horns than heretofore possible. The contribution which the shirred ca~ing article of the present invention thereby makes to the technology comprises a more efficient packaging opera-tion for the s~ufing of food articles of all type~
into available casings.
A particular object of one aspect of the inven-tion is to provide a cored high density shirred casing stick article wherein the core replaces the horn of the stufing machine and thereby becomes a consumeable element o~ the stuffing machine.
An additional particular object of the invention is to provide a cored high density shirred casing stick article, the core element of which may be used seleGtably as a carrier tube or slipping over a stuffing horn on a 5tu~ing apparatus or, alternatively, as the stuffing horn itsel, having a sizing means of one type or another mo~mt.ed on the co~e element of t;he article and disposed 3~5~a~

internally of a deshirred portion of the shirred casing.
BRIEF DESCRIPTION OF THE INVENTION
In contrast to the early use of cores, we have discovered a new use for cores wherein they are designed to restrict the effects of the shirred casing radial inward force to such an extent that not only do we achieve pack ratios which are significan~ly higher than achleved in the prior axt (uncored shirred sticks compacted and shirred under the same conditions), but these higher pack ratios can be attained with casing articles of equivalent or even greater usable bore sizes than possible with the aforementioned comparable uncored shirred sticks. This was contrary to the expectations of one skilled in the ark, that i~, that a core would take up space and thereby reduce the effective bore of the casing stickO Accordingly, one would expect that a core would have a negative effect on pack ratio. Contrary to this expectation, the cored high density cellulosic casing article of this invention can provide a substantially higher pack ratio wi~h no reduction in the useable bore size t and thus ~an result in a cored shirred casing article which has a packing efficiency that is higher than the packing efficiency of an uncored shirred stick. An added feature of the inven-tive article is that it provides a casing article of enhanced structural integrity and strength.
In one embodiment which is particularly useful with stuffing apparatus for the packaging of chunk meat articles such as whole boneless hams and the like, the ..

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core itself of the article according to the invention is used in place of a stuffing horTl. It should be nc~ted, however, in this connectiorl, that the stuffing apparatus for whole boneless hams i~ considered to be a separate invention, the invention il~ this present ca.se being only the adaptation Qf the cored high density concept to such apparatus. It ~ihould be furkher noted that su~h apparatus is the subjec~ matter of a copending applicatio3, Serial No. 261t 313, which is as~igned t:o ~e same as~ignee as 10 this applieation~, An additional embodiment of the invention pro-vides a eored high density shirred casing stick article, the core element o~ which may be u~ed ~electably as a carrier tube ~or slipping over a stufing horn on a ~tuff-15 ing apparatus or, alter3latively, as the stu~Efing hornitself, havialg a sizii~g means of one t~rpe or arlother mounted on the core element of the article and disposed in~ernall y of a deshisred portion of the shirred casing .
Irl general, ~e irlvention comprehends the com-binatior~ of a tubular c:ore t a controllably moisturized 2~ cellulosic ~ood casing length having a moi~ture content of at least about 13 percerlt by total casing weight, shirred and highly ovmpac:ted on said ~:ore to a high pack ratio ~nd to a packing efficierlcy not less than about 0 . 50, ~nd '` `~

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also respectively greater than the pack ratio and packing efEiciency of said same c~sing length shirred and highly compacted under the same shirring and compacting conditions without said core~ thereby generating high ca~ing inward expansio-l force. Ano her aspect of this inventive com bination is that the core is sufficiently rigid to resist de~ormation and reduction of the core bore size from the high casing inward expanslon force. For purposes of this comparison between cored and uncored shirred and compacted 1~ casings, the uncored casing article has no external long-itudinal restralnt.
As used herein, the expression "same shirring and compacting condition~" means that the shirring method and apparatus (for example, including shirrlng means and diameter of the shirxing mandrel) and the final compaction method, apparatus, and length as com-pacted or compaction force, are e~sentially the s~me.
In pre~e~red practice of the invention, the packing efficienc~ is kept at 0.60 and higher.
In a pre~erred embodiment of this coherent casing article, based on a drop fit comparison (herein-above discussed in detail) the core has an inner bore size at least as large as the inner bore size the same casing would have when shirred and highly compacted under the same shirring and compacting conditions without the core. In one preferred embodiment, the casing ~3155~2 ~s~

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is the small unrainforced cellulose type having an in-flated diameter of less than about 40 mm,, and compacted to a pack ratio of at least 100.
In its method aspects, the presen~ invention com-prehends a method for manufacturing a shirred and highly compacted cored casing article comprising the steps of:
(a.) providing a cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight; tb.) sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel having a reduced diameter end portion at the second mandrel end; (c~) shirring said cellulosic food casing length on ~aid mandrel; (d.) providing a hollow core coaxially arranged wi~h and contiguous to the mandrel reducad diameter end portion, said core being sufficiently rigid to resist deformation and reduction of the core bore size from casing inward expansion foxce due to casing com-pacting; ~e.) linearly moving the shirred casing length along the mandrel onto the outer surface of the coaxially arranged core; and, (fO) compacting the shirred casing length on said core to a high pack ratio and to a high packing efficiency, thereby generating said casing inward expansion force.
An alternate embodiment of the present invention comprehends a method for manufacturing a shirred and highl~ compacted cored casing article comprising the 13l55-2 .

steps of: (a.) providing a cellulosic food casing length having a moisture content of a~ least about 13 percent of total casing weight; (b.) sliding the bore inner cir-cumference of sald cellulosic food casing length over a first end o a mandrel; (c.) shirring and compacting said cellulosic food casing length on said mandrel; (d.) pro-viding a hollow core, which is preferably coaxially arranged wlth and contiguous ~o the mandrel second end, said core being sufficiently rigid to re~ist deformation and reduction of the core bore size from casing inward expansion force due to casing compacting; and, (e.) linearly moving the shirred and compacted casing length from the mandrel second end onto the outer surface of the core, so as to provide a hiyh pack ratio and a high packing effi-ciency, thereby genera~ing said casing inwaxd expansionforce as the shirred stick bore contracts.
Another method embodiment of this invention involves a meth~d for manufacturing a shirred and highly compacted cored casing article comprising the steps of: (a.) providing a cellulosic ood casing length having a moisture content of a~ least about 13 percent of total casing weight; (b.) sliding the bore inner circum-ference o~ said cellulo9ic food casing length over a fir~t end of a mandrel; (c.) shirriny said cellulosic food casing length on said mandrel; (d.) providing a hollow core sufficiently rigid to resist deformation and reduction o the core bore size from caslng s~
-2~-inward expansion force due to casing compacting; (e.) moving the shlrred casing length from the mandrel second end onto the outer surface oE the core; and, (f~) further compacting the shirred casing length on said core to a high pack ratio and to a high packing efficiency, thereby gener-ating said casing inward expansion orce. In this embodi-ment, the core is, preferably, supported on a ~econd mandrel, and the shirred casing length i~ transferred onto the core and the second mandrel for compression into the fully com-pacted condition. Additionally, the mandrel supportedshirred casing length may be moved to a secondary position before the shirred casing length is moved from th~ mandrel second end onto the core. Preferably, the core is coaxially arranged with and contiguous to the mandrel second end.
An additional embodiment of ~he present invention constitutes a method for manufacturing a shirred and highly compac~ed cored ca~ing article comprising the steps of: (a.) providlng a cellulosic food casing lenyth having a moisture content of at least ~bout 13 percent of total ca~ing weight; (b.) providing a hollow core suficiently rigid to resist deormation and reduction of the core bore size from casing inward expansion force due to said compacting; (c.) providing a mandrel and longitudinally sliding the bore inner circumference of said core over the outer circumferenae of said mandrel; td.) longitudinally sliding the bore inner circumference of said c~llulosic food casing length over the outer circumference of said ~55~'~

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core; (e.) shirring said cellulose food casing length on said core and mandrel; (f.) compacting the shirred cellulose ood casing length on said core to a high pack ratio and to a high packing eff:iciency, thereby generating said casing inward expansion force; and, (g.) lonyitu dinally sliding the shirred and highly compacted cored casing article off said mandrel.
A further method embodiment of the present inven~ion encompasses a method for manufacturing a shirred and highly compacted cored casing article comprising the steps of: (a.) providing a cellulosic food casing leng-th having a moisture content of at least about 13 percent of total casing weight; (b.~ sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel: (c.) shirring said cellulosic food casing length on said mandrel; (d.) compacting the shirred caslng length on said mandrel to a high pack ratio, and to a high packing efficiency; (e.) providing a hollow core sufficiently rigid to resist deformation and reduction of the core bore size from casing inward expan-sion orce due to casing compacting; and, (f.) longitudinally sliding the compacted shirred casing length off of the mandrel first end and over the outer circumference of said core, so as to provide a high pack ratio and a high 2S packing efficiency, thereby generating said casing inward expansion force as the shirred stick bore contracts.

~6-A still further method embodiment of the present invention embraces a method for manufacturing a shirred and highly compacted cored casing article comprising the steps o: (a.) providing a cellulosic food casi.ng length having a moisture content of at lea~t about 13 percent of total casing weight, (b.) sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel; (c;) shirring said cellulosic food casing length on said mandrel; (d.) provid.ing a hol~.ow core sufic.iently rigid to resist deformation and reduction of the core bore size from casing inward expansion force due to casing compacting; (e.) moving the mandrel-support~.d shirred cellulosic food casing length to a secondary position, preferably into linear and coaxial alignment with said core; (f~ moving the shirred casing length from the mandrel first end onto the outer surface of the core; and, (g.) further compact-i~g the shi~rred casing length on said core to a high pack ratio and to a high packing efficiency, thereby gen-erating said casing inward expansion force. In this embodiment, the core i preferably, supported on a second mandrel, and the partially compacted casing stick is transferred onto the core and the second mandrel for com-pression into fully compacted condition.
The particular moisture content preferred for diferent t~pes o casing may vary. More specifically, the moisture content of controllably moisturiæed shirred . .

fibrous casings in the larger size range would preferably be in the order of from about 16 percent to about 35 percent hy total casing weight.
The preferxed range of moisture content for the intermediate size casings will also be in the order of from about ].6 percent to about 35 percent moisture by weight of total casing.
The smaller size casings used to make frank-furter type products and the like will be advantageously provided with moisture contents by weight of total casing in the order of from about 14 percent to about 1~ percent.
The tubular core element of an article according to the invention must be ~ufficiently rigid to resist deformation and reduction of the core bore size rom the casing inward expansion force, recogni~ing that slight deformation and bore reduction will occur but will be acceptable if not excessive. Core diameter may vary from about 3/8 inch to 5.0 inches or greater, depending upon the casing size and the required bore size. It may vary in wall thickness to suit the particular casing- article and i~s adaptation and utilization, and further in accordance with the core material used, but, in general, it may be stated that the wall thickness of such tubular core is in the range of from about 0.020 inches (0.051 cm) ~5 to about 0.100 inches (0.~54 cm)O

35~

DETAILED DESCRIPTION OF TEIE INVENrION
The invention will now be described in greater particuïarity and with reference to the drawings appended to this specification wherein:
Figure l is an eleva~.ional view of one apparatus which may be used to produce an article according to the invention and in accordance with one inventive method, showing the shirring process in relationship to a contin-uously fed length of casing malerial;
Figure 2 shows khe shirring operation completed and with ~he shirred casing length transported to the compacting section of the apparatus of Figure l;
Figure 3 shows the appllcation of the compacting force to pr~duce the stick length according to the inven-.15 tion on a core el~men~ mounted on the shirring machine extended portion;
Figure 4 is an isometric view of an article according to the invention showing the shirred and compacted casing in place on a hollow tubular core) Figure 5 is an illustration of a variation of the invention adapted for use as a stuffing horn element on ~tuffing apparatus for the processing of chunk meat products;
Figure 6 is an isometric view of an article embodiment according to the invention particularly useful in the stuffing of mid range size products wherein the 13~55-2 55~L~

~ 29~
core element may be used as a support to be slipped over a stuffing horn or alternatively as the stuffing horn portion of the apparatus itself;
Figure 7 is a view of an art.icle in accordance with the invention useful in tlhe stuffing manufacture of ~mall size sausage products wherein the core elemen-t re-places the stuffing horn on the stuffing apparatus;
Figure 8 is a graph showing drop fit as a function of pack ratio for uncored and cored shirred sticks Eormed from 160 feet of size 25 small diameter nonfibrous casing;
Figure ~ is a graph showing coherency as a function o pack ratio for uncored shirred sticks formed from 160 feet of size 25 small diameter nonfibrous casing;
Figure 10 is a graph showing drop fit as a function of pack ratio for uncoxed shirred sticks formed from sizes 17, 21 and 27 small diameter cellulose casing (without fibrous reinforcement~ with all sticks of a particular size having the same length;
~igure 11 is a graph showing coherency as a function of pack ratio for the Figure 10 uncored shirred sticks;
Figure 12 is a graph showing the maximum pack ratio attainahle for uncored and cored shirred s~icks formed from intermediate size fibrous casings in the size 43 to 60 range, to fit a 1.073 inch stuffing horn; and Figure 13 is a graph showing the same relation-ship as Fiyure 12 for intexmediate size fibrous casings 3~;i54~

in the siæe 70 to 100 range, to fit a :L.556 inch stuffing horn.
Referring now to the drawing, there is shown in Figures 1 and 2 a typical fl.oating mandrel-type shirring machine designated generally as 11, comprising a shir.ring mandrel 13 extending through a shirring head 15. An inflated ca~ing 17 .is fed onto the mandrel 13 by a pair o~
feed rolls 19 and a pair of cooperating feed belts 21. The shirring head lS comprises a multi.plicity of shirring ~heels 23, usually three, through which the inflated casing 17 passes, which shirr said casing in conjunction with holdback belts 25 in a manner well known to those familiar with the art. The shirring wheels are of a general type which is described in U.S~ Patent 3~461,484.
The advance of the shirred casing 17 on the mandrel 13 is retarded by an array of holdback belt~ 25 in order to provide a substantially regular pleat formation and a partially compacted shirred casingO After the initial shirring and pleating a~kion, the casing is transferred by the holdback belts further down the mandrel-and towards a first clamp 27.
To effeck the transfer of the shirred casing onto the substantially rigid hollow tubular core and its ultimate compackion thereon in accordance with the inven-tion, ~irst clamp 27 is swung out of the way and ashirred length .is moved manually, or by any conventional automakic means, to the position shown in Figure 2 of the drawing, up against the-second slam? 29. In this 13155-2 ~ .

5S~

position, the shirred casing length is arranged on a hollow tubular core 31 disposed on a necked down or re-duced sectlon of the mandrel 13, as shown in Figure 3 of the drawing which is an enlarged detail of the right hand side of the illustra~ion of Figure 2. The final compac-tion of the casing 17 on hollow tubular core 31 is effected by compac~or 33 which moves linearly towards second clamp 29 until the desired shirred casing stick length is achieved. A holding disc 35 or washer may, advantageously, be inserted between the end of casing 17 and the second clamp 29 so that when the unit article is removed, the casing will be securely held on the hollow tubular core and restrained against slipping off the end thereof.

When a cored high den~ity casing article is completed as described in the foregoing steps, second clamp 29 is removed from its restraining position, and the finished article remo~ed.
The article of this invention may, for example, be assembled by transferring the shirred and ~artially compacted casing onto its hollow tubular core 31 in the manner described hereinabove. Figure 3 of the drawing shows the shirred and partially compacted casing length moved linearly onto a core which is coaxially arrayed with the shirring mandrel 13, on a reduced diameter por-tion thereo, and then applying the ultimate compacting force by means of a compactor 33.

13155-~

~55~L~

-3~-Other methods may be used for placing shirred casing on a core. For example, on a floating mandrel-type shirring machine such as that previously described, the shirred casing may be fully compacted over the shirring machine mandrel and subsequently doffed onto a tubular core. It is also possible to remove the shirred and partially compacted casing length completely from the shirring apparatus ll on a transport rod or carrying mandrel and move the entire length to a separate com-pacting apparatus where the shirred casing length wouldbe placed on a core and compacted. Alternatively, ~he core may be placed on the floating mandrel and then positioned thereon so that the casing is shirred on the core, the cored shirred casing is then fully compacted on the core, and the cored fully compacted casing stick is then do~fed tremoved) from the mandrel.
Another shirxing system, involving use of a withdrawing mandrel ~hirring machine is descrihed in U. S. Pa~ent 2,583~654. This type of shirring system may be used in the rnanufacture of the inventive article, and it allows the shirring of the casing directly onto a core for su~sequent compaction thereon. In one embodiment, the core is placed on the withdrawing shirring mandrel and is positioned thereon so that the casing is shirred on the core, the coxed shirred casing is then fully compacted on the core, and the cored fully compacted casing stick is then doffed from the mandrel. In an 1~155-2 ., ~ .

5~

alternative embodiment, the casing may be shirred and compacted on the withdrawing mandrel in the conventional manner and the shirred and compacted casing may be slid off of the mandrel and onto the core. In a further embodiment, the casing may be shirred and partially compacted on the withdrawing mandrel, the mandrel is then moved to a new posi~ion coaxial with the core, the partially compacted shirred ~tick is slid off o the mandrel and onto the core, and the shirred stick is then Eully com-pacted on the core. It is also possible to remove theshirred and partially compacted casing length completely from the withdrawing mandrel shirring apparatus by doffing onto a transport rod or carrying mandrel and then trans-ferring the partially compacted shirred stick from the transport rod or carrying mandrel onto the core which is mounted in a separate compacting apparatus, where the shirred s~ick.is then ~ully compacted on the core~
The attainment of maximum potential pack ratio with the inventive article requires a high compaction f~rce which, in turnJ induces high inward radial orces within the ~hirred casing stick. Since the preferred method of preparing the inventive article involves com-pacting the shirred casing while in place on its core, it will be appreciated that a low coeicient o friction between the casing and core is desirable. Example VII
(discussed hereinafter in detail) illustrates that a higher pack ratio may be obtained with a core material such .

5~

as high den~ity polyethylene having a relatively low co-efficieal~ of friction~ a~ cc:mpared with poly3?ropylene or p~lystyrene which ha~e higher coe~icients of frictionO
Figure 4 of the drawing shows an article in 5 accordance with the invention, ~pecifically, a moisturized cellulosic ~ood c:asing length 17, shirrad and compacted on a substantially rigid tubular oore 31 ~o a pack ra tiv and a p~cking e~ficiency higher thasn heretofore convention-ally attained . P.lso ~hown in Figure 4 are holding dis c5 10 35 which may optionally be arranged and disposed al: each end of the shlxred ca ing length ~o xetain it in its com-pacted condition on th~ core.
Figure S o:~ $he drawing shows one pre~ently pre~erred embodiment of cored high density ~hirring 15 applied ~o the demountable fituffing hsrnO

In thi~ embodiment, a tiltable casing holdbac3c element 37 i~ ~hown mounted on the hollow 20 tubular core 31 t disposed interiorly of a deshirred length o~ the casing 17 which ha~ been pulled from the ~hirred arad compacted ca6il~g length, over the ~ able ~asing holdba~k el~ment and the end ~f the tubular core/
6tu~f irl~ horn, where it may be clip~closed to provide 25 an ~rld clos~re :Eor the product to be ~tu~fed. A ~lange 39 is provided, a~ ~hown at the opposite esld of the combinatior~ ~rt:icle, to facilitate attachment of the ar~ic:le to the ~tuf~ing ~ppara~us.
..
~, 13155-2 s~

Eigure 6 of the drawing shows the cored hiyh density article according to the invention adapted to a casing carrier or support sleeve to be slipped over the stuffing horn of a stu~fing apparatus. When used in this manner, a flange 39 on such article may be connected to apparatus on the stuffi.ng machine which provides for the reciprocal movement of the entire sleeve to effect slack-ing operations when required in the stuffing process. An embodiment closely similar to that shown in Figure 6 of the dra~ing may, alternatively, b0 used as a sleeve which .includes a sizing or holdback element, in which case, a deshirred portion of the casing would be pulled over the sizing or holdback element and the end of the tubular core, and clip-closed to retain product being stuf~edO

Figure 7 of the drawing shows an article in accordance with the invsntion adapt~d for use in the stuffing manufac~ure of small size sausaye products, provided with a mounting adaptor 41 arranged and disposed to fit directly onto a stuffing machine, the hollow tubu-lar core 31 of the article thus supplanting the conven-tional stuffing horn. In this instance, the casing 17 is partially deshirred, pulled over a sizing el.ement 43 and the end of the tube-horn where it is closed to pro-vide sealing against the product stuffing operation. It is particularl~ advantageous to provide long lengths of casing in a given stick length for the stuffing of small size sausage products, since the production of such products 55~

- -36~

is largely accomplished on high speed automatic stuffing apparatus~ Use of the inventive cored casing article permits use of substantially longer casing lengths within a given stick length for more efficien~ operation of such equipment and, at the same time, meets the high precision dimensional re~uirements (e.g. straightness) and struc-tural integrity (coherency) demanded of casing articles to be used on such equipment.
Figure 7 of the drawing also lllustrates the pleat angle ~ of the casing in the shirred stick form according to the inventian. Conventional shirring on modern shirring machines produces shirred casing sticks with a discernible angular displacement between a plane normal to the longitudinal axis of the stick and a plane in which a shirred pleat lies. An uncored stick having a pleat angle of this nature has, it has been found, significantly greater coherency and structural integrity than such a stick o the same type would have if shirred with the pleat angle normal to the longitudinal axis of the stick, since the overall stick length is-somewhat like a stack of nesti~g cones. The core element provides sufficient structural rigidity o as to remove reliance upon the pleat angle for coherency.
One reason to include some pleat angle ~ in casing sticks, acaording to the invention, is to retard longitudinal stick growth. Shirred casing sticks, immediately after they are doffed from the shirring and/

3155_2 ..... . .

55~

~ 37~
or compacting mandrel, tend to evince growth, which is -the tendency of an unrestrained, shirred and compacted stick to elongate. In the case of uncored shirred and compacted stic~s, there is the further growth of the pleated casing radially inwardly into the bore of the stick, a phenomenon which is increased in proportion to the extent to which lonyitudinal stick gxowth may be restrained.
The tendency of a shi.rred and compacted stick to grow radially inward against the core produces an added locking e~fect of the casing pleats against the core out~r surface~ With this advantageous effect, the tendency of a finished shirxed casing stick to grow longitudinally is substantiall~ reduced by pleat to pleat friction combined with pleat to core frictional force so that only minimal additional longitudinal res~raint is required to dimen-sionally sta~ilize the casing stick article.
EXAMPLE I
_ A 250 foot (76.22 met~rs) length oi large size fibrous casing~ trade designation size 10, having an average flat width of 7.55 inches (19.18 cm) and a wall thickn~ss of .0040 inch (0.10 mm) was shirred using a shirring means very similar to that described in U. S.
Patent 3,461,484 (Arnold). The casing had a moisture .

55~

content of about 20 wt.% based on total casing weight.
As is conventional, a mineral oil lubricant was used.
Internal oi.l was used to reduce mandrel friction and external oil was used for preventing damage to the casing being shirred and undue wear of the shirring rolls. The mineral oil lubricant was applied internally at a rate of about 180 mg~ of oil per lOt) in.2 of casing surface, and externally at a rate of about 100 mg. of oil per 100 in. of casing surace, which amounts had no discernable adverse effect on the finished stick properties. The casing was compacted from one end onto a high density polyethylene cora tube having an inside diameter of 3.75 inches (9.53 cm) and a wall thickness of 0.62 inch (.16 cm) to a shirred stick length of 23.0 inches (58.42 cm). The subject casing article was prepared on a floating mandrel-type shixring machine in a manner described hereinabove wherein the shirred casing is transferred, after shirring and lightly compacting onto a core coaxially arrayed with the shirring mandrel on a reduced diameter portion thereo, finally compacted in place on the core, and dofed. This produced a cored high density hirred casing stick articl~
according to the invention having a pack ratio of 130.4 and a packing efficiency of about 0.757.
For comparison to a control sample, a standard commercially available 150 foot length of the same size and type of casing Was shirred and compacted to the same shirred stick: length of 23.0 inches without a core and found to have a pack ratio of 78 and a packing efficiency 3S~5~

of 0~390, with a bore I.D. of 3 5/8 inches. Other uncored control samples having a higher pack ratio and packing efficiency provided nonfunctional articles be-cause of excessive bore reducti.on due to inward radial growth~
EXAMPLE II
_ The fact that very hi.gh inward forces at the bore of the casing stick are generated as the result o~
the shirring process was demonstrated by experimental work involving the shirriny and compacting, to high pack ratio and high packing ef~iciency, of samples of size 25 ~0.83 inch or 21 mm inflated diameter) small size cell-ulose casing (without fibrous reinforcem~nt) having a casing wall thickness of about 0.001 inch (0.0254 mm).
In the experimental work, 84 foot ('25.61 meters) lengths of the size 25 cellulose casing, about 5 samples each, were shirred using a shirring means very imilar to that described in Arnold ~. S. Patent 3,461,484 while imposing a twi~t to, the shirred stick as set forth in U. S. Patent 3,397,069. The ~hirred stick wa~ then compacted with a compression forc~ of about 400 pounds (181 kg) onto tubular cores having a wall thickness of 0 o O10 inch (0.254 mm), 0.020 inch (0.508 mm), 0O030 inch (0.762 mm), 0.040 inch (1.016 mm), and 0.050 inch (1.270 mm). The cored articles were produced on a floating mandrel-type shirring machine, as described in detail in'this specification, except tha~
during final compac~ion on the core, the core 31 was allowed to sl,ide freely through rear clamp 29 (Figure 3), 1_155-2 --'10,;~ 5~
effecti.vely compactlng ~he casing sirnultaneously from both ends .

All of the tubular cores had an inside diameter of 0.510 inch (1.30 cm) and the compression after shirring was done on a compression mandrel section of 0.500 inch (1.27 cm) diameter with the core elemen~s slipped thereon.
On all samples, moisture content as shirred was about 16~ 5 wta % and mineral oil was used as an internal lubricant (about 14 to 20 mg/100 in2) and external lubricant (up to about 70 mg/100 in2). The lubricant amounts are not critical, but they represent the usual amounts for the lS particular shirriny machine and casing type involved.
The upper portion of Table 1 shows the dimensions of the inside diameters of the cores immediately ater they were doffed or removed from the mandrel, and at least one day and up to 20 days later. Reduction in core in~er diameter was due to the high casing inward expansion force, resulting from the high pack ratio and high packing efficiency. It should be noted that the degree of core bvre reduction is a function o tube diameter as well as the magnitude of inward forces and creep strength of the core (i.e. large casing re~uires greater core thickness than small casing to withstand the same inward force per unit area). It will be noted ~hat the relatively low Unable to recognize this page.

-~2-creep strength of the high density polyethylene permitted ~he .010 inch thick core to compress untll the I.D. of the core (0.480") was actually less than the bore of the uncored sample. The caslng stick bore was, of course, greater (0.480 + 2(0.010)= ~500~) The lower portion of Table 1 shows data on a sample of the same size casing, size 25, shirred and com-pacted on a 0.575 inch mandrel, but uncored, that is without a core. Although high pack ratio and packing efficiency were achieved with "conical" pleats (114.7 and 0~63 respectively) th~re was excessive reduction in bore size ~as determined by drop fit) and this would be unacceptable for commercial practice. It would not be proper to directly compare this data with the Table I
cored article data because each of the cored samples was compacted on a supporting core having an outer diameter which varied according to the wall thickness of the core.
Two pleat angles were used in these Table I
shirring experiments. The designation "S~andup" connotes a shirring pleat angle up to about 15, and the designation "Conical" connotes a shirring pleat angle of about 45~
The "Standup" pleat samples were shirred with shirring means or rolls similar to thoqe described in U. S. Patent 2,984,574 (Matecki). The compressed pack ratio of the uncored conical pleat sample compares with the 210 ft.
uncored sample in Table 2 ! where the stick is useless because of thle loss of coherency.

1?155~2 ~55~'~

The core matarial for the Table 1 experiments was high denslty polyethylene. For convenience, the cores were machined from thick-walled tublng, and the re~ulting rough outer surface somewhat reduced the pack ratio which could be attained. Inspection of Table 1 shows that for high density polyethylene cores, significant distortion of the bore of the casing article occurs even when the core thickne~s is as great as 0.050 inch. It is also shown in Table 1, that for a constant compacting force (in this example 400 lbs.), ~he resulting final pack ratio decreases proportionately as the core thickness increases (i.e. the core outside diameter incxeases). However, the packing efficiency also increases. In order to maximize pack ratio, stuffing horn fit, and packing efficiency, core de~i.gn must take into account (a.) the creep of the core due to high inward casing forces as well as the required final bore size, (b~) reduction of pack ratio that would occur i excessive core wall thickness were used, and (c.) cost of core material.

Other core materials tested produced similar results with regard to core deformation. Cores made of ABS, an acrylonitrile-butadiene-styrene copolymer, tubing worked sa~isfactorily at somewhat lower wall thickness than the high density polyethylene cores, but ABS cores are les5 economical.
EXAMPLE III

The advantages offered by the cored high density cellulose casing articla in terms of packing efficiency 13155-~

~4~ t~

and pack ratio are demonstrated by experimental work in volving the shirring and compacting, to hlgh pack ra-tio and high packing efficiency, of samples of size 25 (0.828 inch or 21 mm inflated diameter) cellulose casing (with-out fibrous reinforcement) having a casing wall thickness of 0.001 inch (0.0254 mm). The casing moisture level asshirred was about 16.5 wt~g6, and mineral oil lubricant was used, as noted in ~xample II. Shirring means of the type in commerclal use and similar to that disclosed in U. S. Patent 3,461,484 to Arnold were used to shirr casing while imposing a twist to the shirred stick as set forth in U. S. Patent 3,397,069, and each stic~ was subsequently compressed onto polypropylene tubular cores (polypropylene reinforced wi~h 20% talc) for comparison with casing shirred by the same shirring methods, but compressed with-out cores. The corèd high density casing articles were produced on a floating mandrel-type shirring machine, described i~ detail in this specification, except that during final compaction on the core, the core 31 was allowed to slide reely through rear clamp 29 (Fig. 3), effectivaly compacting the casing simultaneously from bot~ ends. Additionally, to obtain a more uniform com-pression throughout the shirred casing stick, approxi-mately 80 feet of casing was compacted at a time (incre-mental compression).

_ .. . .

-~5 ~ 5~
The uncored samples and certain of the cored samples are designed to have a 0.490 inch drop-fit. Other cored samples were designed so that the tubular core might serve as a disposable stuEfing horn. In these ins~ances, the inside diameter of the core was effectively e~uivalent to the inside diameter of a 0.5 inch O.D.
stuffing horn and the shirred ar~icle had no particular "drop fit" requirements with respect to the stuffing horn.
For all samples, the shirred casing was compressed to a flnal stik length of about :20 inches. About ten samples were prepared for each of th~ cored configurations and for each of the uncored configurations which comprised casing lengths ranging from 160 to 225 feet.
The results of the experimen~al work axe sum-mariæed in Table 2. For uncored articles having a casing length o 210 feet and over, poor coherency resulted in broken stlcks and drop~fit measurements at one week were not possible. For uncored articles containing casing lengths of 187.5 to 202.5 feet, radial inward forces due to casing growth (af~er one week~ reduced the shirred stick bores to a point where ~hey did not meet the 0.490 inch drop-fit requirement. For comparison purposes, then, the best available shirring methods produced an uncored stick of shirred casing containing 160 feet of casing with an average pack ratio (10 samples) of 94.6 and an average packing efficiency of about 0.491. A cored high density shirred and compacted cellulose casing article of this Unable to recognize this page.

~7-invention designated to have a 0.490 inch drop-fit was produced by the same shirriny method. This produced an article in which the core inner bore was about 59% of the casing inflated diameter. This article contained 200 ~eet of casing and exhibited an average pack ratio (10 samples) of 116.46 and an average packing efficiency of 0.653.
This data also illustrates one preferred embodiment of the invention wherein based on a drop ~it comparison, the core has an inner bore si~e at least as large as the inner bore si2e the same casing would have when shirred and highly compacted under the same shirring and compacting conditions without the core, and to the same pack ratio. More particularly, the core bore size of the 116.46 average pack ratio articles was 0.497 inch.
In contrast, the bore sizes of the uncored shirred sticks with 113.1 and 120.0 pack ratios were 0.470 inch and 0.465 inch xespectively, substantially smaller than the comparable cored article.
A second series of cored hiyh density samples was produced wherein the core of the shirred article would serve as a disposable stuf~ing horn having a throughput capacity effectivel~ equivalent to a standard 0.5 inch O.D~ stuffing horn (0.436 in. I.D.). This pro-duced an article in which the core inner bore was about 51% of the casing inflated diameter. This article con-tained 230 feet of casing, exhibiting an average pack .
., ratio (10 samples) of 133.4 and an average packing efficiency of 0.617.
Further testing was performed to determine the quality of the shirred and compacted casing articles of this Example III (both cored and uncored), as evidenced by the nu~er of pinholes present in the shirred casing.
Five sticks of each sample type were tested for pinholes by filling the casing with water and internal pressuri-æation. The results, shown in Table 2l indicate a general trend o~ increasing pinhole damage as the total casing length o the uncored article increased. In contrast, no pinholes were found in any of the cored samples tested.
In summary, Example III demons~rates that it was not possible to prepare a typical uncored shirred and compactecl small cellulose casing of at least 0.5 packing efficiency without unacceptable bore ldiameter) reduction.
In contrast, this was readily achieved with the article of this invention/ and in fact, the preferred packing e~ficiency of at le~st 0.6 was exceeded.
EXAMP~E IV

. . . _ _ .
Another advantage of the cored high density shirred casing article of this invention i5 that it reduces the tendency towards casing damage, i.e. pin holiny, when compared with the same casing i shirred and compacted uncLer the same conditions without the core.
Thi5 is because the core restrains longitudinal growth due to surface friction, and less compaction is required to maintain a particular pack ratio as compared with an _49~ S ~ ~L~
uncored shirred stick. Since pin-holing increases with increasing compaction, a potential casing damage problem may be reduced or avoided by the article of the present invention.
Further, the core permits the capture and retention of the fully compxessed pac~ ratio and permits even grea~er pack ratios wil:hout pinhole damage.

This compression relationship betw~en cored and uncored shirxed casing sticks was illustrated in a series of tests in which 160 foot lengths of size 25 non-fibrous cellulose casing were shirred and equally compacted with and without a core to a length of 15 inches and an initial pack ratio of 128O After doffing, the cored and uncored shirred sticks were allowed to grow over a seven day period without addi~io~al longitudinal restraint.
At this point, the cored article had only longitudinally grown 0.4 inch (pack ratio after growth of about 125) whereas the uncored article had grown 1.4 inches (pack ratio after growth o about 117). If the obiective had been a final pac~ ratio of 125, higher initial compaction force would have been required with the uncored shlrred stick.
The advantage of less ~endency toward casing 131S5-2' ~35~

damage may be utilized in another manner. If the practi-tioner identifies a maximum compaction force which may be used without causing casing damage when using this force, the cored article may be formed at a higher pack ratio and higher packing efficiency than an uncored article.
EXAMPLE V
A series o experiments was performed based on the teachings of the previously referenced British Patent 1,167,377, assigned to Viska~e, Ltd., and comparing sams with the cored high density shirred cellulosic stick of this invention.
Based upon the te~chings of the above identified British Paten~, a polyvinyl chloride tube with 1.613 inch I.D. and a 0.010 inch wall thickness was used as a core element, and Size 2~ fibrous reinforced cellulosic casing (about 2~4 inches inflated diameter) was shirred by shirr-ing means simllar to that disclo6ed in U. S. Patent 3,461,484 (Arnold) and thereafter compressed to a length of 12.0 inches.
The tube I. D. of 1.613 inch and the Size 2~ fibxous casins were 5elected for thi~ test work because this was the smallest polyvinyl chloride tube which was available at the time o~ this tes~. The sample casing arti~les were prepared on a 10ating mandrel-type shirring machine in a manner previously described in detail in this specification, wherein the shirred casing is transferred after shirring onto a core coaxiall~ arrayed with the shirring mandrel ~51-on a reduced diameter portion thereof, finally compacted in the ~xample I manner, and doffed. These samples had a moisture content as shirred of about 20% and mineral oil lubricant was used internally (a.bout 200 mg/100 in2) and externally (up to about 107 mg/l.00 in2). The casing was provided in three different lengths: 75, 100 and 125 feet. Based on the compacted ar.ticle, differing pack ratios wexe obtained~ The resulting articles were then measured to determine the core inside diameter by the aforedescribed "drop fit" procedure. For the ~5 pack ratio sample, the drop fit size was 1.590 inches, thereb~
showing a core diameter size reduction of 0.023 inch.
For the 100 pack ra~io sample, the dxop fit size was 1.540 inches, thereby showing a core diameter size reduction of 0.073 inch. For the.125 pack ratio sample, the drop fit size was less than 1.500 inches. However the core buckled at one end immediately after the article was compressed and doffed from the mandrel. This demon-strates the inability to obtain the cored high density shirred cellulosic stick of the invention by following the ~eachings of the ~ritish Patent.
The 75 foot example would still fit the 1.556 inch O.D. stuffing horn, but the packing eficiency would be only 0.43. The 100 foot samples caused bore shrinkaye so great that they would not fit the horn. The 125 foot sample core collapsed completely.

5~
~52-EXAMPLE VI
Fibrous cellulosic casing articles similar in size to that used for the British patent-type sample described in Example V were prepared according to the subject invention and compared with uncored samples in order to explore the limits of compressibility as e~tab-lished by damage to the casing. Size 2~ (about 2.4 inch infla~ed diameter) and Size 4 ~abou~ 2.8 inch inflated diameter) casings ~ere shirred by shirring means similar 1~ to khat disclosed in U. S. Patent 3,461,484 (Arnold).
The moi~ture content of the Size 2~ and 5ize 4 samples as shirred was about 20~. Mineral oil was used as a lubri-cant as follows:
Size 2~ - about 200 my/100 in2 (internal) and about 100 mg/100 in2 (external) - Size 4 - about 170 mg/100 in2 (internal) and about 90 mg/100 in (external) The cored articles were compacted on polyvinyl chloride (PVC~ cores in a mannex identical to tha~ used ~or Example V articles, The samples were compacted to a 12.0 inch length at a pack ratio of 150, which represented the highest pac~ ratio attainable with no damage to the Si~e 2~ casing. All samples were designed to fit on a 1.556 inch diameter stuffing horn. The cores used had an outside diameter of 1u713 inch and a wall thickness o~ 0.05 inch.
Cored samples were restrained from longituinal expansion by the use of a peg and uncored samples were restrained (~nly partially) by containment within a cardboard carton.

~55~

The results of the tests are shown in Table 3.
The Size 2~ cored articles showed a final core bore si~e slightl~ too small for fitting the horn~ but still larger than the bore o~ the uncored ar1icles, even though the cored articles had a pack ratio of about 138 while the uncored articles had a pack ratio of only about 114. In practice, a slightly lower pack ratio would have provided an adequate horn fit with the core. The Size 4 cored articles were functional ~in terms of pack ratio~ after 15 1~ days at a pack ratio of 138.46. Size 4 Imcored articles exhibited a bore size reduction to a point of nonfunction-ality after 15 days with a measured pack ratio of 128.48.
This Example VI also demonstrates, for cored fiber reinforced casing articles, one preferred embodiment of the invention wherein, based on a drop it comparison, the core has an inner bore size at least as large as the inner bore si~e the same fibrous casing would have when shirred and highl~ compacted under the same shirring and compacting conditions without the core, and to the same compressed pack ratio. For example, wi~h the Size 2~
casing the average uncored casing bore size of 1.540 inch wa~ slightly smaller than the average cored inner bore size of 1.547 inch, even though the latter's final pack ratio was substantially higher.(l38 compared to 114). Similarly, with the Size 4 casing, the average uncored cas~ng bore size of 1~547 inch was substantially smaller than the average cored casing bore siæe, even though the latter's Unable to recognize this page.

flnal pack ratio was higher (138 compared to 128)~
Comparison of the test results ~escribed above with those of Example V demonstrate that the British Patent 1,167,377 does not teach or even suggest the use of a core in a manner which will permit the simultaneous achievement of the three advantageous characteristics of the cored cellulosic casing article of this invention:
high pack ratio, high packing efflciency, and limited deformation-reduction of the core bore size.
EXAMPLE VII
Still another series of tPsts was performed using a shirrlng means of th~ general type described in U. S. Patent 3,461,484 (Arnold) while imposing a twist to the shirred stick as set forth in U. S. Patent 3,397,069.

In these tests the cored high density small diameter shirred cellulose casing articles were prepared using different core materials. The cored articles were pro-duced on a floating mandrel-type shirring machine, as described in detail in this specification, except that during final compaction on the core, the core 31 was allowed to slide freely through rear clamp 29 (Fig. 3), thereby effectively compacting the casing simultaneously from both ends.

The core materials used in the tests were polypropylene (reinforced with a 20% talc filler), polystyrene, and high density 55~

polyethylene, each core having an outside diameter of 0.5 inch and a wall thickness of 0.025 inch. The casing used was size 25 cellulose (no fibrous support), and each casing article contained 200 feet of casing. On all samples, moisture content as-shirred was about 16.5~
and mlneral oil as a lubricant was used internally (about 14 to 20 mg/lOO in2) and exterrlally (up to about 70 mg/
lOO in ).
The test results, summarized in Table 4, demon-strate that the relatively lower coefficient of friction of the high density polyethylene core allowed compaction of the shirred casing to a significantly higher pack ratio than that obtained for the other core materials.
From the experimental work of Examples II and VII, it can be seen that the design of a core for the present invention will be based on core material proper-ties such as strength, modulus of elasticity and creep resistance. These properties will determine the core wall thickness re~uired to resist casing inward expansion forces which tend to distort and reduce the core bore size. The core material coe~ficient of friction will determine the magnitude oE the longitudinal compacting orces which are needed to compress the casing to extre-mely high pack ratios.
It appears that many factors enter into the choice of core material lncluding coefficient of friction, creep strength, modulus of elasticity, availability in extruded form, cost, formability, weldability, and avail-Unable to recognize this page.

55~

ability in reinforced form. The final choice may be different for different applications. High density poly ethylene and polyvinylchloride (PVC) are suitable for laxge casing embodiments of this invention.
EXAMPLE VIII
Another serles of tests was performed with cored high density casing articles similar to those described in Example III and summarized in Table 2. The only difference is that instead of final compaction from both end~, compact.ion was from one end in the same manner as practiced with the Table 2 uncored shirred casing sticks, and the compacted shirred sticks were transferred onto the core.
The results of these cored high density article tests, with non-fibrous Si~e 25 cellulose casing, are summarized in Table 5, and should be compared with the Table 2 uncored casing data~ The cored high density article designated to have a 0.490 inch drop fit exhibited an average pack ratio (15 samples) of lZ9.2 and an average packing efficienc~ of 0.67. The cored high density article designated to serve as a 0.5 inch O.D. stuffing horn exhibited an average pack ratio (15 samples) of 140.1 and an averaye paaking efficiency of 0.64 In summary, while Example III demonstrates that it wa~ :not possible to prepare a typical uncored shirred and compacted small cellulose casing of at least 0.5 packing efficiency by~single end compaction without unacceptably high ~ore reduction, this was readily . .
13 .~-2 , 55~

SMALL SIZE CASING
.

FOR DISPOSAB~E
FOR DROP FIT HOR~ EQUIVALE~T
OF 0.490 INCH 50 0.5 I\C5 UO~
Compxession Section Diameter, Inches 0.575 0.512 Tubular Core 0 oD
x IoD~ ~ Inches 0.560 x 0.510 0.500 x 0O450 Casiny Length, Ft. 200 200 Stick .Length, In~
Compressed 17 . 0 15~0 Dofad 18. 63 17 .1 1 Week 18.58 17.13 Stick Pac~ Ratio Compre~sed 141.2 160.0 Doffed 128.8 140.,3 1 W~eX 129n 2 140.1 Stick OoDo ~ Inches Compressed ~A NA
Doffed 0.983 0~939 1 Week 0.979 -0.987 SticX Drop Fit, Inches Do f ~ed 0 . 498 0.430 1 Week 0.494 0.423 Stick Packing Efficiency (After 1 Week) 0 . 67 0 . 64 ~A means data not availableO
., ]~3155-2 ".

5~

-~o achieved with the article of this invention, and in fact, the preferred packing efficiency of at least 0.6 was exceeded. Equipment was not available for double ended compaction of uncored sticks.
EXAMP~E IX
Still another serles of tests was performed in which Size 25 cellulose casing (without fibrous rein-orcement) was used to prepare uncored and cored high density shirred articles at various pack ratios, and examined from the standpoints of drop fit (Figure 8) and coherency tFigure 9). All artlcles were prepared from 160 feet of casing and the compacted shirred articles were of different lengths, depending on the pack ratio.
The casing moi~ture level as shirred was about 16.5 wt.~
and mineral oil was used as an internal lubricant (about 14 to 20 mg/100 in2 of internal surEace) and external lubricant (up to about 70 mg/100 in o external surface) during shirring~
. Shirring means of the type disclosed in U. S.
Patent 3,461,484 (Arnold) were used to shirr casing, while imposing a t~ist to the shirred stick as set forth in U~ S.
Patent 3,397,069, and the casing was fully compacted in the conventional manner from one end on the mandrel compression section of a floating mandrel-type shirring machine as generally depicted in Figure 3. After compaction, the shirred casing stick was doffed directly onto a tubular core.

13~)5~2 ~5~

The ~atter was formed of polyvinyl chloride having 0.560 inch O.D. x 0.506 inch I.D~ For one group of tests, the compression section mandrel diameter was 0.575 inch. For t~e other group of tests, the compression section mandrel diameter was 0.595 inchO
The drop fit and cohe.rency for both uncored and cored high density shirred arti/.les were measured, along with pack ratio, seven days after doffing, and the data is summarized as functions of pack ratio in Figures 8 and 9.
Figure 8 shows that the drop fit for both uncored compacted shlrred 5ticks (0.575 ~nd 0.595 inch mandrel compre5sion sections) continuously decline with increasing pack ratio in the 95-120 pack ratio range.
Since the minimum acceptable bore size for Size 25 casing (inflated diameter of 0.83 inch~ i~ 0.490 inch ~horizontal dashed line), the maximum usahle pack ratio ~or the 0.575 inch mandrel is about 99. It will be noted that by using a larger mandrel ~0.595 inch~, the minimum bore s.ize may be achieved at slightly higher pack ratio (about 103~, but this increases the probability of casing damage due to pin-holingO Also, progressively larger mandrel sec-tions, greater than about 0~575 inch for Size 25, pro-gressively increase the probability of seizing on the ~5 mandrel, increase production interruption, and increase waste rate. Stated otherwise, it is well recogni ed by those skilled in the shirring art that the optimum set-up for trouble-free shirrability of a particular casing 131~5-2 -6~-size is one whlch uses the smallest mandrel which will achieve the desired bore size.
In contrast to the aforedescribed uncored shirred stick pack ratio limitation due to bore size requirement (about 99~, Figure 8 demonstrates that for Size 25 cored casing, the drop fit wa~ constant with in-crea~ing pack ratio up to a pack ratio of about 124, using the same 0.575 inch mandrel size. With further increase in pack ratio, the core inner bore size ~egins to inwardly deElect due to excessive inward force from the shirred stick~ Accordingly, 124 represents a practical upper limit in pack ratio for ~his particular embodiment wherein the casing inflated diameter is about 0.83 inch, the pack ratio is greater than lOO, and the drop fit is at least 0.490 inch.
It has been unexpectedly discovered that when the pack ratio of uncored shirred stic~s of cellulose casing (without fibrous reinforcement) is in the region of pack ratios achievable with the cored casing ~rticle of this in~ention, coherency of the uncored sticks pro-gressively decreases with increasing pack ratio. This is contrary to expectations since at lower pack ratios, as used in commercial practice, the coherency of the same uncored stick is known by the art to progressively in-crease with increasing pack ratio.
This unexpected discovery that coherency declineswith increasing pack ratio for uncored shirred cellulose casing sticks is illustrated in Fiyure 9 for Si~e 25 1 ? ~

_, _ _ .,. _ , ~5~

casing. It will be noted that for a 0.575 inch mandrel, coherency declines at a nearly constant and high rate from about 5 (pack ratio of 100) to at least as low as 1.5 (pack ratio of 125)~ The latter pack ratio is only s slightlv above the minimum commercially acceptable coherency of 1.2 and it is subs~an~ially below the pre-ferred coherency o~ 2.5. In contras~, with the cored high density shirred casing article oE this invention, there is no coherenc~ limitation because the compacted shirred casing i~ supported by and in functional contact with the core outer wall.
Although not fully understood, it is speculated that the aforedescribed coherency - pack ratio relation-ship for uncored shirred cellulose casing sticks is re lated to the degree of casing pleat compression. A
possibla explanation is that in the lower pack ratio range the compression of the pleats generates a tighter nesting of the indlvidual cones, thereby increasing the contact area between adjacent cones and thus increasing the coherency. Ho~ever, as the COmpreSSiQn is further in-creased to create even higher pack ratios, the high com~
pression may disrupt nestlng of the cones, thereby reducing the coherency. This possible explanation is consistent with the experimental observation that as pack ratio of uncored shirred cellulose casing sticks is progressively increased, coherency initially increases to a maximum value and then progressively decreases. The possible explanation is also consistent with the experimental observation that larger casing sizes have higher coher-ï3 ~

~3S~

-6~
encies at highe.r pack ratio~ than smaller casing sizes (see Flg~re 11 discussed hereinafter). This may be due to the larger surface areas of adjacent cones in contact with each other in relatively 1.arge size casings.
The da~a for Size 25, 160 foot casing, which is summarized in Figures 8 and 9 also supports the broad requirements of this invention that the cored article have a packing eff1ciency not less t:han 0~50, and that its pack ratio and packing efficiency be re6pectively sreater than the pack ratio and packing ef~iciency o the same casing length, shirred and highly compacted under the same shirring and compacting conditions, without the core~
More particularly, the seven day charact~ristics of the samples, (a) the highest pack ratio cored article which satisfied the minimum 0.490 inch drop fit requirement, (b~ the uncored article which was shirred and compact~d under the same conditions as sample (a), and (c) the highest pack ratio uncored article which also satisfied the same minimum drop fit requirement, were as follows:
- Packing Sample D ~ Pack Ratio Efficiency (a) cored article 0.50 inch124 0.66 (b) uncored article 0.46 inch 116 0.54 (c) uncored article 0050 inch 98 0.44 This data shows that the drop fit, pack ratio and packing e~ficiency of sample (a) were all higher than sample (b)o Moreover, sample (b) was not an acceptable product because the stick grew inwardly into the stick .. . ~ .

~55~4 bo.re to the extent that the sample (b) stick did not satisfy the minimum drop fit requirement. Recognizing this deficlency in bore size for sample (b), uncored article (c) was the best uncored shirred stick which would perform the same function as cored article (a).
On this basis, sample (a) represented a 26~ improvement in pack ratlo and a 50% improvement in packing efficiency.
EX~MPLE X
_ _ A further series of tests, similar to the Example IX t~sts with Size 25 casing, was performed with three differing (smaller and larger) sizes of cellulose casing without fibrous reinforcement. They were Size 17 (0.61 inch in1ated diameter and wall thickness of 0.001 inch), Size 21 (0.73 inch in~la~ed diameter and wall thickness of 0.001 inch), and Si~e 27 (0089 inch inflated diameter and wall thickness of 0.001 inch). One difference from the Example IX tests is that instead of using the same length of casing and preparing different stick lengths depending on the pack ratio, in these tests the çasing length was varied and the sticks were compressed to provide about the same final stick length for each casing size (7 days after doffing). For Size 17 ca~ing the ~inal stick length was about 16 inches, whereas with Size 21 and 27 casing the final stick length was about 20~ inches.
Another difference between these tests and those of Example IX is that there ware no cored articles of ~3~.~J-~ .

~5~

this invention prepared from Size 17, 21 or 27 casing.
However, ln another similar test, a cored high density shirred cellulose casing article was prepared from Size 21 casing, and it had the following characteristics: pack ratio o 119.8; packing efficiency of 0.66; and core inner bore size of 0.422 inch. Thus, this cored shirred casing article was suitable for use on the intended 0.406 inch O.D. stuffing horn. As is demonstrated by the uncored shirxed stick curves for Size 21 casing in Figures 10 and 11 (discussed hereinafter), these outstanding character-is~ics cannot be even approached by the prior art uncored shirred casing~
With the exception of the aforedescribed differarlces, the Size 17, 21 and 27 uncored high density shirred sticks were prepared in the same manner as the Size 25 uncored high density shirred sticks. After doffing and seven days storage withou~ longitudinal restraint, the resulting sticks were then subjected to drop fit and coherency measurements, The data is summarized in the Figure 10 (dxop fit) and Figure 11 (coherency) curves as a function of pac~ ratio.
Inspection of Figure 10 reveals that like Size 25 casing (Figure 8), the drop fits of all three sizes progressively decrease with increasing pack ratio at sub~
2S stantially constant rates, For Size 17 casin~, the minimum acceptable drop -fit is 0~360 inch tsee dashed hori-zontal line), so that from the drop fit standpoint, the maximum pack ratio attainable with the prior art uncored r r ~ ~

5~

67~
shirred stick i5 abou~ 80. Similarly, with Size 21 casing, the minimum acceptable drop fi.t is 0.410 inch so the max-imum pack ratio at-tainable with the prior art uncored shirred stick is about 98. Finally, for Size 27 casing, the minimum acceptable drop fit is 0,530 so the maximum pack ratio attainable with the prior art uncored shirred stick is about 130.
Referring now to the coherency versus pack ratio curves of Figure ll, all show the previously discussed unexpected relationship of declining coherency with increas-in,g pack ratio in the upper range of pack ratios ~or each casing size. For Size 17, the coherency over the entire tested range of 60-125 pack ratios i5 low, recoynizing the minimum accep~able value of 1.2 (horizontal dashed line).
For Size 17 uncored shirred casing, the maximum attainable pack ratio rom the coherency standpoint is also about 80.
For Size 21, the aoherency over the entire tested rang~ of 70-120 pack ratios is also low, and based on the minimum acceptable coherency value of 1.2, the maximum attainable pack ratio from the coherency standpoin~ i.s about 102.
For Size 27 uncored shirred casing, the afore described full range of coherency versus increasing pack ratio relationships is illustrated. That is, for pack ratios up to about 120, the coherency increases with in-creasing pack r~tio. However beyond pack ratios of about122, coheren.cy decreases at an approximately constant and fairly sharp rate~ ~
Based on Fi.gure~ lO and ll, it will be apparent ~5~

that drop it and coherency requirements place substantial restrictions on the use of high pack ratios with prior art uncored shlrred sticks formed from Sizes 17, 21 and 27 cellulose casingsO In each instance~ the article of this inven~ion may provide substanti.ally higher pack ratios with acceptable core bore size and h.igher coherency, and with less tendency towards casing damage in the form of pin-holes.
More particularly, a cored shirred Si~e 17 casing article of this lnvention with a casing in~lated diameter of about 0.61 inch and a dxop fit of at least: 0.360 lnch preferably has a pack ratio greater than 80. Also, a cored shirred Size 21 casing article of the invention with a casing inflated diameter of about 0.73 inch and a drop fit of at least 0.410 inch preferably has a pack ratio greater than 98.
Finally, a cored shirred Size 27 casing article of the invention with a casing inflated diame-ter of about 0.89 inch and a drop fit of at least 0.530 inch preferably has a pack ratio greater than 130.
EXAMPLE_XI
The pack ratio and packing efficiency advantages of the in-termediate size fibrous reinforced~type casing article em~odiments of the invention were demonstrated in still another series of tests involving both cored and uncored samples. Size 43, 47 and 60 casings having flat 25 widths in the size range of about 2.30 to 3.30 inches were used to prepare shirred and compacted, cored and un-cored stick articles to it a s~uffing horn of 1.073 +
0.005 inch outside diameter. Size 70, 80 and 100 casings 1;L55--2 ~5~

having flat widths in the size range of about 3.75 to 5.50 inches were used to prepare shirred and compacted cored and uncored stick articles to fit a stufflng horn of 1.556 +
O.005 inch outside diameter. The casing wall thickness for all sam~les was about 0.0031 inch. The casing moist-lre level as shirred was about 20~, and mineral oil was used as an internal lubricant (about 44 mg/lO0 in2 of internal surface) and external lubricant (up to about 30 mg/100 in2 of external surface). The inflated diameters of these fibrous reinforced casings are as follows:
Size Inflated Diameter (Inches) 43 1.480 47 1.588 2.063 lS 70 2.387 ~.772 100 3.4~5 In these tests, different casing lengths were compres~ed to obtain substantially the same stick length at all pack ratios for a particular size casing. Th~se compressed stick lengths were as follows: Size 43, 10.5 inches; Size 47, 10.0 inches; Size 60, 9.0 inches;
Size 70, 12.0 inches; Size 80, 12.0 inches; and Size 100, 12.0 inches.
All sample casing articles we.re prepared on a floating mandrel-type shirring machine as previously de-scribed. The shirring means were of the type in commer-l~.5:5-2 ' ~S5~

-70~
cial use and similar to tha~ disclosed in Arnold U. S.
Patent 3,461,484. ~lultiple samples were prepared at each condition. The uncored samples were shirred and compressed from one end on the mandrel to that maximum pack ratio which allowed no casing damage, and to lower pack ratios.
The maximum "no-damage" pack ratio was determined by testing for holes by filling with water and internal pressurization. When damage was detected, additional samples were prepared at sligh-tly lower pack ratios and these samples were water tested for pin holes as noted.
The sequence was repeated until a pack ratio was reached with no casing damage, and ~his represented the maximum pack xatio~
After compaction on the mandrel, the Size 43, 47 and 60 uncored samples were transferred from the shirring machine to a small diameter (1.1 inch) plastic tube for handling purposes, and after about one hour, were removed from the tubes and inserted in netting. The lat~er was clipped at both ends, and the clipped-end netting overwrap represents commerclal practice to facilitate handling.
This arrangement provides a slight restraint on longitudinal growth~ The Size 70, 80 and 100 uncored samples were trans-ferred rom the shirring machine directly into a polyvinyl chloride film overwrap which provided very limited end restraint. Again this represents commercial practice for handling purposes.
The cores were made of rigid polyvinyl chlorideO

.
13155-~

5S~

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For casing Sizes 43, 47 and 60, the core outside diameter was 1.230 inch and the wall thickness was 0.050 inch.
For casing Si~es 70, 80 and 100, the core outside diameter was 1.713 inch and the wall thickness was also 0.050 inch.
After shirring, the t:o-be cored samples were longitudinally moved from the mandrel onto cores which were coaxially arrayed with the shirring mandrel around a reduced diameter portion of the mandrel, in the manner previously described and illustrated in Figure 3. The shirred stick was then compacted to the desired pack ratio on the core by compression from one end, and doffed. The cored samples were compressed to pack ratios equivalent to those for the uncored samples.
After doffing, the cored shirred casing article was provided with means equivalent to core mounted holding discs 35 and flange 39 (as shown in Figure 6) at opposite ends of the shirxed stick to maintain the doffed length during the seven day storage period. This degree of longitudinal end restrain~ would not be practiced with uncored sticks because they would either buckle or grow inwardly to the extent of not fitting the desired stuffing horn. Accordingly, the netting and plastic film overwrap used with the uncored sticks, did not substantially restrain longitudinal ~rowth.
The stick lengths were measured before doffing of both uncored and cored samples and again measured after the seven day storage period. The results of these 131~-2 35~

~72~
measurements are shown in Figure 12 for the size 43, 47 and 60 fibrous reinforced casings and in Figure 13 for the si~e 70, 80 and 100 fibrous casings, with pack ratios plotted as a function of casing flat width.
S In both Figures 1~ and 13, the lowest curve represents the uncored shirred and compacted stick after seven days storage. The middle curve represents the cored shirxed and compacted article also after seven days storage, and the uppermost curve (dashed line) represents the cored shirred and compacted article immediately after compaction.
The latter is included because it represents an achieveable state with the present invention, which is unattainable with the prior ar-t uncored shirred stick. That is t by "capturing" the cored article opposite ends after compaction but prior to doffing, as for example with longitudinal end restraint means, the initial (and highest~ pack ratio may be retained with no loss of other essential stick charact-eristiss. For example~ there is minimal loss of bore si~e because the compacted stick is restrained from radial inward growth b~ the coreO However, if one used longitu-dinal end restrai~t means with an uncored stick immediately after doffing, the initial highest pack ratio would be retained but there would be additional inward bore growth, beyond that which occurs without longitudinal end restraint.
Since the practitioner uses the smallest possible shirring mandrel.for optimum resuits (for reasons previously ex~
plained), in all likelihood, the additional radial inward .. . . ~ . .
1315~ 2 ~S~44 growth would result in a bore size which is too small to fit the intended stu~fing horn.
More speclically, Fi.gure 12 shows that based on comparison of the seven day pac:k ratio values for size 43-60 fibrous reinforced casing ~lcored and cored article (two lower curves), the least improvement is with Size 43 casing, and here the diEference is about 78 minus 60, or a pack ratio improvement of about 30% when using the cored article. The largest improvement is with Size 60 casing, and here the d.ifference is 129 minus 79, or about a 63%
improvement in pack ratio using the cored article. The potential maximum improvement based on comparison of the uncored seven day pack ratio tlowest cu.rve) with the initial ~ighest pack ratio (highest, dashed line curve) is substa~tially greater. For example, with Size 43 casing the differe~ce is 97 minus 60, or about a 62% higher pack ratio, and wi~h Size 60 casing ~he difference is 146 minus 79, or about 85%.
A comparison of packing efficiencies and pack ratios for the uncored and cored shirred fibrous casing article~ of Sizes 43, 47 and 60 as described in this Example XI is as follows:
Packing Efficiency (and Pack Ratio) Casing_Size Uncored (7 days) Cored (7 days) Cored (Initial) 43 0.54 (60) 0.7~ (78) 0.78 (82) 47 0.53 (66) 0.76 (95) 0.81 (102) 60 0.45 (79) 0.75 (130) 0.85 (147) i5~

Figure 13 shows -that based upon a comparison of the seven day pack ratio values for the Size 70-100 fibrous reinforced casing uncored and cored artlcle, the pack ratlo improvement is less than with the Size 43-60 casing, but still substantial. The least improvement is with Size 80 casing~ and here the difference is 166 minus 154, or abou~ 8~. The potential maximum improvement based on comparison of the uncored seven day pack ratio with the initial highest pack ratio for Size 80 casing is 180 minus 154, or about 17~.
A comparison of packing efflciencies and pack ratios Eor the uncored and cored shirred fibrous casing articles of Sizes 70, 80 and 100 as described in this Example XI is as follows:
Packing Efficlency (and Pack Ratio) Casing Slze ~ncored (7 days) Cored (? days) Cored ~Initial) 70 0.~ (129) 0.77 (141) 0.82 (150) 8~ 0O63 (154) 0.71 (166) 0.77 (180) 100 0.50 (167) O.S9 (187) 0.70 (220) Although coherency is also important with fibrous reinforced cellulosic casings, it does not present the same sexious problems as wi.th small diameter unreinforced cellulose casings. This is in part because the former are inherently stronger due to the iber reinforcement, bu~ also because of differences in the stuffing apparatus used for each.
'rhe small diameter cellulose casings are 1;L5:~ - 2 typically stuffed using hiyh speed completely automated machinery wherein the next stick to be used is automatically advanced into stuffing position when the previous stick is exhausted. Poor coherency can cause broken sticks, which in turn may cause casing breakage or tearing upon insertion or rotation of the automated stuffing horn. When this happens, a considera~le quantity of food emulsion is released to the surro~mdings before the apparatus can be stopped, and substantial "down" time is needed for clean-up and removal o~ the broken casing.
In contxast, with larger diameter fibrouscasings the machine speed is usually slower and the next stick is manually positioned for use by the operator. If there is casing breakage (less likely because of fibrous reinforecment), the apparatus can be stopped before a substantial quantity of foodstuff has been released and the "down" tlme is shorter~
EXA~PLE XII
Before discovery of this invention, applicants' 2~ a~signee, Union Carbide Corporation, de~eloped and marketed a machine, the SHI~TIC~ Model 405 Sizer, for stuffing deboned whole muscle hams into large diameter fibrous re-inforced cellulojic casings of the type previously de-scribed. It was designed to use shirred casin~ with a sizing disk implanted in one deshirred end of the uncored shirred stick. At the outset of the machine design, the need for maximum bore size of the stuffing horn was recog-. .
i13155-2 nlzed, as wel.l as the limitation on horn size imposed by the maximum obtainable bore of the shirred casin~ stick.
To ohtain the rnaximum horn size, the horn wall thickness was reduced to the minimum acceptable from the strength standpoint, the casing length was necessarily and undesir-ably reduced from 200 feet to 150 feet, and the shirring conditions were optimized for the largest attalnable bore size. Also, the tension sleeve wall thickness and the clearance over the stuffing horn were necessarily and undesirably reduced to the minlmum acceptable dimensions~
The re~ult of these efforts was the use of the highest state o shirring art then available, and the use of a 3 3/8 inch in3ide diameter stuffing horn. The origi-nal as-marke~ed SHIRM~TIC Model 405 Sizer is described in detail in Belgium Patent No. 888,526. A substantial number of these machine~ were installed in meat packing plants, but for mo~t applications they were found to be unsatisfactory. It was observed that the extreme elonga-tion of the ham pieces while passing through the horn and 9ubse~uent "jumbling" when stuffed into the casing caused the surface fat to turn into the interior of the stuffed encased hams and caused poor muscle fiber grain arrange-ment. The system was not deemed by the meat packers to be equi~alent to hand stuffing, and attempts to market the SHIR~ATIC Model 405 Sizers were temporarily suspended.
Tests were then run in the food laboratory o the applicants' assignee usin~ laxger stufing horns and unshixred cas.ing. These tes-ts demonstrated conclusively 1~.L55-2 .

o 1 7--that a larger horn size wc~uld solve the problems being encountered with the SHIRMATIC Model 405 Sizer, and that the hams prs~duced with a larger ~tuf fing horn were as good as hams produced by hand ~tuffirlg, By this time t applicants had begun developing the cored high density shirred c asing ~tick of 1:he present inventivn. Development wor}c ~howed that utilizing the inventive cored h.igh density ~hirred casing stick as a ~turfillg horn resulted is~ an increase sf the horll I.D. to 3 3/4 inchO Part Qf thi gain ~n horrl size was due to the elimirlati~n o the tension sleeve of the SHIR~TIC ~lodel 405 Sizer~

A~ ~ resul~ o~ ~h~se modi~ication~ ~o ~he S~IRtqATIC ~50del 405 Sizer, 'che horn ~ize i~creased ~or a Size 10 fibrous ca~ing from a 3 3J8 inch I oD ~ ~ c) i~l 3 3~/4 inch I.rl. mis is a diame~er gain o 3~8 in h or 11..1~6.
2û This diameter increase in turn provides an ef fective increase in cro~-sectional area ~or ~he inside of ~he i;tuffing ho~ of 23O5%o Of this 23.,5% ~r~crease in horn cross-section, 7 . 59~ i~ attributable to the eliminaîio~
of the prior art ten~ion sl~eve and 16 . 0~ is attributa}: le 25 to the u~e of the cored high d~nsity shirred product of the present inventio~.
Addi.tionally, by modifying the ~tuffir~g horn i4~

and using the cored casing stick in this manner, it was possible to increase the pack ratio of Si~e 10 fibrous casing from about 78 to about 130, which is a 67~ increase.
Also, the packing efficiency was increased from 0.39 to 0.76, and the casing length was increased from 150 ~ee~ to 250 feet. This modification of the stufing system i~ now being marketed as the SHIRMATIC Model 405H System. Example I of this Specification is a specific illustration of a cored fibrous casing article used in the Model 405H System.
This example also illustrates the preferred embodiment o~ the cored article wherein based on a bore size comparison, the core has a bore size at least as large as the inner ~ore size the casing would have when shirred and highly compacted under the same shirring and compacting conditions without the core, and to the same pack ratio. In particular, based on Si~e 10 fibrous casing, the modified machine (SXIRMATIC Model 405H) with the cored article employs a core with a 3-3/4 inch bore size, wherleas the inner bore size of the uncored shirred stic~ was about 3-5/8 inch when shirred and compacted to a pack ratio of 78. The core used with this particular size casing is formed of high density polyethylene and has a wall thickness of 0.062 inch.
After the modification program was completed, the SHIRM~TIC Model 405~I System was taken back to the meat packers who were dissatisfied with the original SHIRM~TIC
Model 405 5izler, and they have now accepted the Model 405H

3S5~

System as an important improvement in ham stuffing. Ten months after introduction of the SHIRMATIC Model 405H
System, twenty machlnes were in commercial use and more of such machines are being installed at meat packing facilities on a regular basis. The SHIRMATIC Model 405 Sizer has now been withdrawn from the market for the pre-viously stated reasons, and the outstanding success of the SHIRM~TIC Model 405H System is clearly attributable, in great part, to the presenk invention.
1~ The invention then, as hereinabove described, provides a signiicant advance in the art. More shirred casing in a given stick length permits longer continuous production runs. Higher packing efficiency provides a more ~avorable combination of high pack ratio and large bore siza which can maintain or impxove stuffing character-istics while achleving the ionger continuous production runs. The invention completely eliminates coherency and stick growth problems that heretofore have plagued pro-ducers and users of small casing. The moisturized (no-50ak) eature o~ the article of this invention - is espe-cially advantageous since the characteristically high pack ratios cannot be practiced with casing in which thP
soaking i5 done by the casing user prior to stuffing. This is because the tight pleats would inhibit entrance of the water into the casing wall and adequate soaking would not be accomplished within a commercially acceptable period of time.

-8~-It should be understood that for purposes of comparing inner bore circumferences for cored and uncored shirred and compacted casing articlesl the comparison should be made at least about one week afker manufacture.
Embodiments of the i:nvention o-~her than those described hereinabove, but wit:hin the spiri~ and scope of this invention, may, in the light o this disclosure, occur to persons familiar with the art. It is intended, there-~ore, that the foregoing de~ripkion of the invention be construed ag illu~trative only and not in any limiting sense, the in~ention being properly defined and limited by the appended claims.

131'~-2

Claims (48)

WHAT IS CLAIMED IS:

1. A coherent casing article comprising, in combination;
a tubular core; and, a moisturized cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight, shirred and highly compacted on said core to a high pack ratio and to a packing efficiency not less than about 0.50, and also respectively greater than the pack ratio and packing efficiency of said same casing length shirred and highly compacted under the same shirring and compacting conditions without said core, thereby generating high casing inward expansion force:
said core being sufficiently rigid to resist deformation and reduction of the core bore size from said high casing inward expansion force.

2. A casing article according to claim 1 wherein said packing efficiency is not less than about 0.60.

3. A casing article of claim 1 wherein said casing contains fibrous reinforcement and the casing moisture content is in the order of from about 16 percent to about 35 percent by total casing weight.

4. A casing article according to claim 1 wherein the casing inflated diameter is a size of from about 1.5 inches (3.8 cm) to about 3.9 inches (9.9 cm), the outside diameter of the tubular core is from about 1.0 inches (2.54 cm) to about 2.0 inches (5.08 cm), and the pack ratio of unshirred to shirred length of casing is from about 50 to about 360.

5. A casing article according to claim 4 wherein the tubular core wall thickness is from about 0.040 inch (0.10 cm) to about 0.060 inch (0.15 cm).

6. A casing article according to claim 1 wherein the casing inflated diameter is less than 1.4 inches (3.6 cm) and the moisture content of the casing is from about 14 percent to about 18 percent by total casing weight.

7. A casing article according to claim 1 wherein based on a drop fit comparison, said core has an inner bore size at least as large as the inner bore size the same casing would have when shirred and highly compacted under the same shirring and compacting conditions without said core.

8. A casing article according to claim 7 wherein said casing is a small unreinforced cellulose casing having an inflated diameter of less than about 40 mm.

9. A casing article according to claim 7 wherein the pack ratio is at least 100.

10. A casing article according to claim 1 wherein the inflated diameter of said casing is from about 4.0 inches (10.2 cm) to about 6.00 inches (13.44 cm), the outside diameter of the tubular core is from about 3.0 inches (7.6 cm) to at least about 5.0 inches (12.7 cm), and the pack ratio of unshirred casing length to shirred casing length is from about 100 to about 190.

11. A casing article according to claim 10 wherein such tubular core wall thickness is from about 0.050 inch (0.127 cm) to about 0.075 inch (0.19 cm).

12. A casing article according to claim 1 wherein the tubular core wall thickness is at least about 0.020 inch (0.05 cm).

13. A casing article according to claim 1 wherein the tubular core comprises high density poly-ethylene.

14. A casing article according to claim 1 wherein the tubular core comprises polyvinylchloride.

15. A casing article according to claim 1 wherein the said pack ratio is not less than about 70.

16. A casing article according to claim 1 wherein said pack ratio is not less than about 70 and said packing efficiency is not less than about 0.60.

17. A casing article according to claim 1 wherein the casing inflated diameter is a size of from about 2.6 inches to about 3.9 inches, the outside diameter of the tubular core is from about 2.0 inches to about 3.0 inches, and the pack ratio of unshirred to shirred length of casing is from about 100 to about 200.
article

18. The casing/according to claim 17 wherein the tubular core wall thickness is from about 0.040 to about 0.075.

19. A casing article according to claim 1 wherein the casing is a small unreinforced cellulose casing having an inflated diameter in the range of from about 0.50 inches to about 1.50 inches, having an inner core bore diameter which is at least 40% of the casing inflated diameter, and a core with a thickness in the range of from about 0.010 inch to about 0.050 inch, with a packing efficiency of at least 0.60.

20. A casing article according to claim 19 in which the pack ratio is at least 100.

21. A casing article according to claim 19 in which the inner bore diameter is at least 50% of the casing inflated diameter.

22, A casing article according to claim 20 in which the inner bore diameter is at least 50% of the casing inflated diameter.

23. A casing article according to claim 19 in which the pack ratio is at least 120.

24. A casing article according to claim 19 wherein the casing inflated diameter is about 0.61 inch, the pack ratio is greater than 80, and the drop fit is at least 0.360 inch.

25. A casing article according to claim 19 wherein the casing inflated diameter is about 0.73 inch, the pack ratio is greater than 98, and the drop fit is at least 0.410 inch.

26. A casing article according to claim 19 wherein the casing inflated diameter is about 0.83 inch, the pack ratio is greater than 100, and the drop fit is at least 0.490 inch.

27. A casing article according to claim 19 wherein the casing inflated diameter is about 0.89 inch, the pack ratio is greater than 130, and the drop fit is at least 0.530 inch.

28. A method for manufacturing a shirred and highly compacted cored casing article comprising the steps of:
a. providing a cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight;
b. sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel having a reduced diameter end portion at the second mandrel end;
c. shirring said cellulosic food casing length on said mandrel;
d. providing a hollow core coaxially arranged with and contiguous to the mandrel reduced diameter end portion, said core being suffi-ciently rigid to resist deformation and reduction of the core bore size from casing inward expansion force due to casing compacting;
e. linearly moving the shirred casing length along the mandrel onto the outer surface of the coaxially arranged core; and, f. compacting the shirred casing length on said core to a high pack ratio and to a high packing efficiency, thereby generating said casing inward expansion force.

29. A method according to claim 28 in which said packing efficiency is not less than 0.50.

30. A method according to claim 28 in which said pack ratio is at least 70.

31. A method according to claim 28 in which said pack ratio is at least 70 and said packing efficiency is not less than 0.60.

32. A method according to claim 31 in which the pack ratio is at least 100, said food casing is small diameter cellulose without fiber reinforcement, and the inner core bore diameter is at least 50% of the casing inflated diameter.

33. A method according to claim 32 in which the pack ratio is at least 120, said food casing is small diameter cellulosa without fiber reinforcement, and the inner core bore diameter is at least 40% of the casing inflated diameter.

34. A method for manufacturing a shirred and highly compacted cored casing article comprising the steps of:
a. providing a cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight;
b. sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel;
c. shirring and compacting said cellulosic food casing length on said mandrel;
d. providing a hollow core, said core being sufficiently rigid to resist deformation and reduction of the core bore size from casing in-ward expansion force due to casing compacting; and, e. linearly moving the shirred and compacted casing length from the mandrel second end onto the outer surface of the core, so as to provide a high pack ratio and a high packing efficiency, thereby generating said casing inward expansion force as the shirred stick bore contracts.

35. The method of claim 34 wherein the core is coaxially arranged with and contiguous to the mandrel second end.

36. A method for manufacturing a shirred and highly compacted cored casing article comprising the steps of:
a. providing a cellulosic food casing length having a moisture content of at least about 13 percent; of total casing weight;
b. sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel;
c. shirring said cellulosic food casing length on said mandrel;
d. providing a hollow core sufficiently rigid to resist deformation and reduction of the core bore size from casing inward expansion force due to casing compacting;

e. moving the shirred casing length from the mandrel second end onto the outer surface of the core; and, f. further compacting the shirred casing length on said core to a high pack ratio and to a high packing efficiency, thereby generating said casing inward expansion force.

37. The method of claim 36 wherein the core is supported on a second mandrel.

38. The method of claim 37 wherein the shirred casing is transferred onto the core and the second mandrel.

39. The method of claim 36 wherein the mandrel-supported shirred cellulosic food casing length is moved to a secondary position before the shirred casing length is moved from the mandrel second end onto the core.

40. The method of claim 36 wherein the core is coaxially arranged with and contiguous to the mandrel second end.

41. A method for manufacturing a shirred and highly compacted cored casing article comprising the steps of:
a. providing a cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight;
b. providing a hollow core sufficiently rigid to resist deformation and reduction of the core bore size from casing inward expansion force due to said compacting;
c. providing a mandrel and longitudinally sliding the bore inner circumference of said core over the outer circumference of said mandrel;
d. longitudinally sliding the bore inner circumference of said cellulosic food casing length over the outer circumference of said core;
e. shirring said cellulose food casing length on said core and mandrel;
f. compacting the shirred cellulose food casing length on said core to a high pack ratio and to a high packing efficiency, thereby generating said casing inward expansion force; and, g. longitudinally sliding the shirred and highly compacted cored casing article off said mandrel.

42. A method for manufacturing a shirred and highly compacted cored casing article comprising the steps of:

a. providing a cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight;
b. sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel;
c. shirring said cellulosic food casing length on said mandrel;
d. compacting the shirred casing length on said mandrel to a high pack ratio and to a high packing efficiency;
e. providing a hollow core sufficiently rigid to resist deformation and reduction of the core bore size from casing inward expansion force due to casing compacting; and, f. longitudinally sliding the compacted shirred casing length off of the mandrel first end and over the outer circumference of said core, so as to provide a high pack ratio and a high packing efficiency, thereby generating said casing inward expansion force as the shirred stick bore contracts.

43. A method for manufacturing a shirred and highly compacted cored casing article comprising the steps of: .

a. providing a cellulosic food casing length having a moisture content of at least about 13 percent of total casing weight;
b. sliding the bore inner circumference of said cellulosic food casing length over a first end of a mandrel;
c. shirring said cellulosic food casing length on said mandrel;
d. providing a hollow core sufficiently rigid to resist deformation and reduction of the core bore size from casing inward expansion force due to casing compacting;
e. moving the mandrel-supported shirred cellulosic food casing length to a secondary position;
f. moving the shirred casing length from the mandrel first end onto the outer surface of the core; and, g. further compacting the shirred casing length on said core to a high pack ratio and to a high packing efficiency, thereby generating said casing inward expansion force.

44. The method of claim 43 wherein the core is supported on a second mandrel.

45. The method of claim 44 wherein the partially compacted casing is transferred onto the core and the second mandrel.

46. The method of claim 43 wherein the core is coaxially arranged with and contiguous to the mandrel second end.

47. A coherent casing article comprising in combination:
(a) a substantially rigid yet appreciably compressible tubular core of substantially uniform wall thickness and having a substantially straight cylindrical bore formed to a diameter slightly greater than a certain diameter required for the article to fit over, or to serve as, a stuffing horn for filling a certain cellulosic casing with foodstuff;
(b) on said core a compressed tubular causing stick composed of a shirred and longitudinally compacted length of said cellulosic casing having a moisture content of at least about 13 percent of total casing weight, said casing stick having pleats encircling said core and said pleats being longitudinally compacted so tightly that they exert on said core radially inward forces which, but for being constrained by said core, would cause inward growth of said pleats to an inside diameter less than said required diameter;

- 93a -(c) said core being contracted appreciably by said forces, but resisting them so strongly that it prevents them from contracting said core to an inside diameter less than said required diameter; and (d) said compressed tubular casing stick having and retaining in the course of time, a pack ration of casing length to casing stick length greater than the pack ration which is retained in the same course of time by a substantially identically shirred and longitudinally compacted but thereafter inwardly unconstrained casing stick formed of identical casing and having an inside diameter no less than said required diameter.

48. A coherent casing article as claimed in claim 50 wherein said compressed tubular casing stick retains, in the course of time, per unit of its length, a volume of said cellulosic casing which is substantially greater than the volume of identical casing which is retained in the course of time in the same unit length of a substantially identically shirred and longitudinally compacted, but thereafter inwardly unconstrained, compressed tubular casing stick having an inside diameter no less than said required diameter.