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Title:
APPARATUS AND METHOD FOR TURNING AND SHIRRING FLEXIBLE TUBULAR CASINGS
Document Type and Number:
WIPO Patent Application WO/2012/084728
Kind Code:
A1
Abstract:
The present invention relates to a method for turning and shirring a flexible tubular casing, in particular a food casing, wherein the flexible tubular casing is guided through a turning and shirring tube, after emerging from the latter is turned, guided back and slipped over a tubular region of the turning and shirring tube, and is then shirred by appropriate apparatus means. The invention also relates to an apparatus for carrying out this method.

Inventors:
HENZE-WETHKAMP HEINRICH (DE)
KRALLMANN ANTON (DE)
Application Number:
PCT/EP2011/073096
Publication Date:
June 28, 2012
Filing Date:
December 16, 2011
Export Citation:
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Assignee:
CASETECH GMBH (DE)
HENZE-WETHKAMP HEINRICH (DE)
KRALLMANN ANTON (DE)
International Classes:
A22C13/02
Foreign References:
DE3101424A11982-09-02
DE1479836A11969-03-27
DE1198988B1965-08-19
DE1479836A11969-03-27
DE3101424A11982-09-02
EP1192864A22002-04-03
Attorney, Agent or Firm:
GODEMEYER, Thomas et al. (An den Gärten 7, Overath, DE)
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Claims:
Claims

An apparatus for carrying out a method for turning and shirring a flexible tubular casing (1), wherein the apparatus comprises:

a turning and shirring tube (2) comprising an internal space (3), a base (4) having a flexible tube inlet opening (5) , a flexible tube outlet opening (6) opposite the base (4), a tubular region (7) that begins at the flexible tube outlet opening (6) and is suitable for receiving a turned flexible tubular casing (1) that emerges at the flexible tube outlet opening (6), and

apparatus means (8, 9), which are arranged to the side of the turning and shirring tube (2) in the tubular region (7), for shirring a flexible tubular casing (1) turned at the flexible tube outlet opening (6),

characterized in that the internal space (3) of the turning and shirring tube (2) is connected to a port (10) for compressed gas.

The apparatus as claimed in claim 1, wherein the tubular region (7} is adjoined directly or indirectly in the direction of the base (4) by a funnel-shaped region (12) having an outside diameter that increases with respect to the tubular region (7), or by a tubular region (12) having a preferably greater outside diameter than the outside diameter of the tubular region (7).

The apparatus as claimed in either of the preceding claims, wherein the flexible tube inlet opening (5) is in the form of a slit and/or the flexible tube outlet opening (6) is circular. The apparatus as claimed in one of the preceding claims, wherein the flexible tube inlet opening (5) is provided with sealing means (13) .

The apparatus as claimed in one of the preceding claims, wherein at least the tubular region (7) is single-walled.

The apparatus as claimed in one of the preceding claims, wherein the turning and shirring tube (2) has gas passage openings (11) which are arranged in the tubular region (7) and are preferably distributed around the circumference of the tubular region (7} and spaced apart from the flexible tube outlet opening (6) in the direction of the base (4) such that, while the apparatus is being operated and the method is being carried out, a gas cushion forms around the entire circumference in at least a part of the tubular region (7), so that the flexible tubular casing (1) is not in contact with the turning and shirring tube (2} at least in this part.

The apparatus as claimed in claim 6, wherein the gas passage openings (11) are bores and/or punched holes and/or other openings.

The apparatus as claimed in one of the preceding claims, wherein the apparatus means (8, 9} comprise at least two shirring wheels (8, 9).

The apparatus as claimed in one of the preceding claims, additionally comprising a rebounding wall (14), which is arranged in a manner spaced apart from the flexible tube outlet opening (6) and with the aid of which the turning point (15) of the emerging flexible tubular casing (1) can be set. A method for turning and shirring a flexible tubular casing (1) using the apparatus as claimed in one of claims 1 to 9, comprising the steps of: guiding one end of the flexible tubular casing (1) to be turned through the flexible tube inlet opening (5) and into the internal space (3} ,

guiding the end out of the internal space (3} through the flexible tube outlet opening (6), turning the end of the casing (1) so that the inside (16) of the turned part of the casing (1) becomes the outside (17) and the outside (18) of the turned part of the casing (1) becomes the inside (19),

guiding back the end of the casing (1) and slipping it over the tubular region (7) of the turning and shirring tube (2) ,

circumferentially fastening the turned and guided-back end of the casing (1) to the turning and shirring tube (2) between the tubular region (7) and the base (4) by way of fastening means (20) ,

supplying compressed gas through the port (10) into the internal space (3) so that the casing (1) guided through the turning and shirring tube (2) is driven through the turning and shirring tube (2) and is turned outside the turning and shirring tube (2) downstream of the flexible tube outlet opening (6), and

shirring the casing (1) , which has been slipped over the tubular region (7) of the turning and shirring tube (2), by way of the apparatus means (8, 9),

characterized in that, on account of the supplied compressed gas, a gas cushion is formed around the entire circumference in at least a part of the tubular region (7) so that the casing (1) is not in contact with the turning and shirring tube (2) at least in this part.

The method as claimed in claim 10, wherein the turning point (15) of the casing (1), which has been turned outside the turning and shirring tube (2) , is set with the aid of the rebounding wall (14) .

The method as claimed in either of claims 10 and 11, wherein the supply of the compressed gas through the port (10) establishes an overpressure in the range of from 0.05 to 0.5 bar, preferably in the range of from 0.05 to 0.15 bar, in the turning and shirring tube (2) .

The method as claimed in one of claims 10 to 12, wherein the flexible tubular casing (1) is guided through the flexible tube inlet opening (5) as a laid-flat material and the flexible tube inlet opening (5) is in the form of a slit.

The method as claimed in one of claims 10 to 13, wherein, before the casing (1) is introduced into the turning and shirring tube (2), the inside (16) of the casing is coated in a contiguous manner at least in portions, preferably by guiding a standing bubble (21) containing a coating substance .

The method as claimed in one of claims 10 to 14, wherein, before the casing (1) is introduced into the turning and shirring tube (2), the outside (18) of the casing is coated and/or printed on partially at least in portions or contiguously at least in portions. The method as claimed in one of claims 10 to 15, wherein, before the casing (1) is introduced into the turning and shirring tube (2) , the casing is pretreated, preferably predried or moistened, at a station (22) .

Description:
Apparatus and method for turning and shirring flexible tubular casings

The present invention relates to a method for turning and shirring a flexible tubular casing, in particular a food casing, wherein the flexible tubular casing is guided through a turning and shirring tube, after emerging from the latter is turned, guided back and slipped over a tubular region of the turning and shirring tube, and is then shirred by appropriate apparatus means. The invention also relates to an apparatus for carrying out this method.

In the food industry, there is increasing demand for food casings, in particular sausage casings, having functional layers on the inside of the casings, said functional layers being intended to have a particular effect on the filling material after the casing has been filled with the food or the sausage emulsion. The application of such functional layers places high demands on the coating method. Furthermore, it should be possible to carry out the method in a cost-effective manner. Mentioned here as functional layer are color layers, flavoring layers and smoke layers for sausage casings, said layers, after the sausage emulsion, has been filled and cooked, giving off their color, flavor and also their smokiness to the sausage emulsion. In addition, the application of herbs in combination with color, flavor and smoke can also be considered to be a functional layer.

Conventional layers are barrier layers composed of, for example, PVDC or acrylic layers as barrier layers. In the broader sense, impregnations on casing surface can also be considered to be functional layers. Impregnations serve for example to set the sausage emulsion adhesion between the casing surface and the sausage emulsion. Examples of casings which may be provided with functional layers on their insides are flexible tubular films of all kinds and diameters and thicknesses, with and without a seam, in particular single-layer and multilayer plastic films and plastic casings, cellulose fibrous casings, coated cellulose fibrous casings and textile casings.

Functional layers can be applied to a flexible tube from the outside or from the inside. Application to this layer via the inside can be carried out in such a way that the substance to be applied is passed into the flexible tube and the substance is guided in the flexible tube roll as a "standing bubble". If the formulas are intended to be applied via the outside, there are many more variants for the actual application. Suitable external application methods are methods such as printing, coating, knife coating, etc.

The simpler and also more precise method is application to the outside of the flexible tubular casing. In particular when the formulas involved are fixed by being dried after application, application via the inside of the flexible tubular casing cannot be used.

During the drying process, the liquid constituents of the coating are converted into the gas phase and this gas phase can as a rule not penetrate through the relatively gas-impermeable film tube.

It has to be considered a major disadvantage of the method involving external coating that the flexible tubular casings have their functional layer on the wrong side, i.e. on the side facing away from the contents. Therefore, the flexible tubular casing has to be turned inside out after the outside has been coated. The external layer has to be turned to become the internal layer so that this layer can come into contact with the sausage emulsion.

Turning the casing after the flexible tubular casings have been coated or during end-processing in the form of shirring has not yet been achieved properly. In particular turning and shirring in one working step on a machine represents a very large obstacle in practice.

The end-processing form of shirring has established itself in practice. By shirring, the flexible tubular casing is brought into a form which allows it to be filled with sausage emulsion in one operation and without interruptions over a relatively great length. As a result, at least a semicontinuous mode of operation during filling can be achieved. A particular casing length of for example from 20 to 150 m is shirred to form a stick having a length of from 200 to 1000 mm. The shirring method has been known for a long time. Independently of the known shirring method, axial shirring, spiral shirring or screw shirring is also known, such that during shirring a particular spacing is set between the shirring tube and the flexible tubular casing. This spacing can be achieved by a slightly increased internal pressur in the flexible tubular casing or by an externally applied negative pressure, for instance by way of a vacuum unit. Only by way of this spacing can the desired shirring pleats laid one on top of another be produced.

DE 14 79836 describes a turning method in which the flexible tubular casing is taken off a roll, guided through a tube and then turned inside out around the tube. According to the patent, the incoming side of the flexible tubular casing is sealed with sealing materials, such as flexible materials or leather, for example. Subsequently, compressed air is introduced into the system, so that the flexible tubular casing is taken off the roller and is turned from the inside to the outside by way of the compressed air. In this case, there is no stationary turning point, but rather the turning location moves in the take-off direction. In this method, only the turning of the casing is described.

DE 3101424 presents a method in which a flexible tubular casing is taken off a roll. Then, it is pushed through a special turning and shirring tube, turned inside out around a turning ring at the end of the turning and shirring tube and shirred. This turning ring has an outlet opening for air. This is intended to reduce the contact between the flexible tubular casing and the turning tube. The turning process itself thus takes place directly at the tip of the turning tube. In the expanded version, further methods, such as coating and printing with and without external drying can be incorporated in the process step between the taking of the flexible tubular casing off the roll and the turning and shirring tube. After this intermediate step, the flexible tubular casing runs through the turning and shirring tube again and is subjected to the subsequent shirring. In EP 1 192 864, an externally printed flexible tubular casing is shirred normally. After shirring, one end of the flexible tube is guided through the internal bore in the stick. The pulled-in end of the shirred stick produced in this way is pushed onto the filling tube and the pulled-out end is passed into the clipping station of the filling machine. During filling at the filling machine, the casing is pulled out of the stick and as a result the outside turns to the inside.

It has been shown in practice that the methods from the prior art have disadvantages or cannot be used in all cases. Also, operating faults and possibly damage to the casing may occur in known methods.

It was therefore the object of the present invention to develop an apparatus and a method, with which turning and shirring can take place in one working step. The method should be readily possible with all possible types of flexible tubular casings and, be able to be carried out in particular in as gentle a manner as possible for the flexible tubular material. Also, the apparatus used for the method should have as simple and robust a manner of construction as possible.

The object is achieved by an apparatus with which a flexible tubular casing can be turned and shirred, the apparatus comprising:

a turning and shirring tube comprising an internal space, a base having a flexible tube inlet opening, a flexible tube outlet opening opposite the base, a tubular region that begins at the flexible tube outlet opening and is suitable for receiving a turned flexible tubular casing that emerges at the flexible tube outlet opening, and apparatus means, which are arranged to the side of the turning and shirring tube; in the tubular region, for shirring a flexible tubular casing turned at the flexible tube outlet opening, characterized in that the internal space of the turning and shirring tube is connected to a port for compressed gas. The apparatus according to the invention enables a method in which the flexible tubular casing can be taken off a roll and then guided into a pressure chamber, specifically the turning and shirring tube, with a special sealing means. After leaving the turning and shirring tube, the flexible tubular casing is turned inside out, pushed from the outside over the turning and shirring tube and at the end of the turning and shirring tube sealed off from the turning and shirring tube. The apparatus is designed such that the positive pressure required for turning does not leave the system to a large extent or that the pressure required for the turning and shirring process is set in advance and is kept constant at the preselected pressure during the process in progress.

Surprisingly, the positive pressure required for turning can also be used as a positive pressure during the process of shirring the flexible tubular casing.

On account of the fact that the turning location is executed not ' directly at the tip of the turning tube, where in particular high mechanical stress would occur on account of friction against the tip, but rather at a distance therefrom, the actual turning process is carried out very gently.

As explained further below, the turning location can be set with a suitable apparatus.

The apparatus. is thus constructed such that turning and shirring lead to only relatively low stressing of the resting edges and of the flexible tube material at the turning point .

In a preferred embodiment, the apparatus is constructed such that the tubular region is adjoined directly or indirectly in the direction of the base by a funnel- shaped region having an outside diameter that increases with respect to the tubular region, or that the tubular region is adjoined directly or indirectly in the direction of the base by a further tubular region having a preferably greater outside diameter than the outside diameter of the first tubular region.

In a preferred embodiment, the flexible tube inlet opening is in the form of a slit while the flexible tube outlet opening is preferably circular.

In order to reduce pressure losses within the turning and shirring tube, the flexible tube inlet opening is preferably provided with sealing means. These sealing means are preferably configured such that they are slidable, . non-abrasive, sealing and non-scratching. Possible sealing materials are soft textiles, leather, Teflon or similar materials.

The housing of the turning and shirring tube, in particular the tubular region that begins at the flexible tube outlet opening, may be configured in a single-walled manner.

In a particular embodiment of the apparatus according to the invention, the turning and shirring tube has gas passage openings which are arranged in the tubular region and are preferably distributed around the circumference of the tubular region and spaced apart from the flexible tube outlet opening in the direction of the base such that, while the apparatus is being operated and the method is being carried out, a gas cushion forms around the entire circumference in at least a part of the tubular region, so that the flexible tubular casing is not in contact with the turning and shirring tube at least in this part. The gas passage openings may be configured as desired, as long as they ensure that enough compressed gas can pass between the external wall of the tubular region that begins at the flexible tube outlet opening and the casing that is slipped over this region. Also, the openings should be such that no protruding edges, ridges or other elevations can damage the slipped-over casing. Preferably, the gas passage openings are bores and/or punched holes and/or other openings.

In one particular embodiment, the tubular region that begins at the flexible tube outlet opening can also be configured in a double-walled manner. In this case, gas passage openings can be provided only in the internal wall of the double-walled region and additionally gas passage openings that are directed forward can be provided. "Forward" means that the openings are arranged at the tip of the turning and shirring tube in the transition region from the internal wall to · the external wall of the double-walled region. As a result of such an arrangement, the gas pressure acts not only from the internal region of the turning and shirring tube but also additionally directly at the tip of the turning and shirring tube in the transition region from the internal wall to the external wall.

By way of this measure, the casing can be oriented concentrically around the shirring tube, which has a smaller diameter. Specifically, it is important during the shirring process that the inflated casing is always spaced apart from the shirring tube directly before the actual shirring process. The spacing in the form of "trapped" air between the casing and the turning tube ensures that the shirring geometry, e.g. lamellar or screw form, can dip into the space between the inflated flexible tubular casing and the shirring tube and relative movements in the longitudinal direction are possible with respect to the flexible tubular casing. These movements lead to what are known as shirring pleats. The flexible tubular casing is then laid in pleats onto the shirring tube.

The apparatus means for shirring (shirring system) may comprise shirring wheels, wherein at least two shirring wheels should be provided in this case. Preferably, these shirring wheels are fixed in position and rotate about themselves. Other shirring systems, such as axial shirring, which comprises for example four shirring wheels that rotate about themselves and about the casing, or spiral shirring or screw shirring, can also be used.

In a particular embodiment of the apparatus according to the invention, said apparatus additionally comprises a rebounding wall, which is arranged in a manner spaced apart from the flexible tube outlet opening and with the aid of which the turning point of the emerging flexible tubular casing can be set. Technically, the turning operation takes places between the outlet of the casing from the turning and shirring tube and the rebounding wall.

The present invention also comprises the method with which a flexible tubular casing can be turned and shirred, that is to say a method for turning and shirring a flexible tubular casing, wherein the above- described apparatus can be used. The method comprises the following steps:

guiding one end of the flexible tubular casing to be turned through the flexible tube inlet opening and into the internal space in the above-described apparatus, guiding the end out of the internal space through the flexible tube outlet opening,

turning the end of the casing so that the inside of the turned part of the casing becomes the outside and the outside of the turned part of the casing becomes the inside,

guiding back the end of the casing and slipping it over the tubular region, that begins at the flexible tube outlet opening, of the turning and shirring tube,

circumferentially fastening the turned and guided- back end of the casing to the turning and shirring tube between the tubular region that begins at the flexible tube outlet opening and the base of the turning and shirring tube by way of fastening means,

supplying compressed gas through the compressed gas port into the internal space so that the casing guided through the turning and shirring tube is driven through the turning and shirring tube and is turned outside the turning and shirring tube downstream of the flexible tube outlet opening, and

shirring the casing, which has been slipped over the tubular region, that begins at the flexible tube outlet opening, of the turning and shirring tube, by way of the above-described apparatus means for shirring,

characterized in that, on account of the supplied compressed gas, a gas cushion is formed around the entire circumference in at least a part of this tubular region so that the casing is not in contact with the turning and shirring tube at least in this part.

In a particular embodiment of the method according to the invention, the turning point of the casing, which has been turned outside the turning and shirring tube, can be set with the aid of the above-described rebounding wall.

Typically, the supply of the compressed gas through the compressed gas port in the turning and shirring tube establishes an overpressure in the range of from 0.05 to 0.5 bar, preferably in the range of from 0.05 to 0.15 bar. In a typical embodiment of the method according to the invention, the flexible tubular casing is guided through the flexible tube inlet opening as a laid-flat material. In this case, it is preferred for the flexible tube inlet opening to be in the form of a slit.

In principle, all casing types in all common calibers are suitable for turning and shirring with the apparatus according to the invention or according to the method according to the invention. Particularly suitable are casings, which are flexible and thin- walled and also have a low coefficient of friction with respect to themselves. In the case of multilayer casings, it is advantageous if they have a good bond adhesion.

The method according to the invention can be carried out such that, before the casing is introduced into the turning and shirring tube, the inside of the casing is coated in a contiguous manner. This can take place by guiding a standing bubble containing a coating substance .

Alternatively, or in addition, the method according to the invention can be carried out such that, before the casing is introduced into the turning and shirring tube, the outside of the casing is coated and/or printed on partially at least in portions or continuously at least in portions.

The method according to the invention can also be supplemented to the extent that, before the casing is introduced into the turning and shirring tube, the casing is pretreated at a station in some desired or necessary manner. For example, before being introduced into the turning and shirring tube, the casing can be predried or moistened, for example in order to set the turning capability or flexibility of the casing material .

Figure 1 schematically shows the apparatus according to the invention for carrying out the method according to the invention for turning and shirring a flexible tubular casing.

Figure 1 shows a turning and shirring tube (2) comprising an internal space (3), a base (4) having a flexible tube inlet opening (5} , a flexible tube outlet opening (6) opposite the base (4), a tubular region (7) that begins at the flexible tube outlet opening (6) and is suitable for receiving the turned flexible tubular casing (1) that emerges at the flexible tube outlet opening (6), apparatus means (8, 9), which are arranged to the side of the turning and shirring tube (2) in the tubular region (7), for shirring the flexible tubular casing (1) turned at the flexible tube outlet opening (6), a port (10) for compressed gas and also gas passage openings {11} which are arranged in the tubular region (7) and are distributed around the circumference of the tubular region (7) and spaced apart from the flexible tube outlet opening (6) in the direction of the base (4) . Also shown is a funnel-shaped region (12) which adjoins the tubular region (7) in the direction of the base (4) and has an outside diameter that increases with respect to the tubular region (7), sealing means (13) at the flexible tube inlet opening (5), and also a rebounding wall (14) which is arranged in a manner spaced apart from the flexible tube outlet opening (6) and the turning point (15) of the emerging flexible tubular casing (1) . Figure 1 also shows how, by the casing (1} being turned, the inside (16) of the turned part of the casing (1) becomes the outside (17) and the outside (18) of the turned part of the casing (1) becomes the inside (19). In figure 1, the casing (1) is fastened to the external wall of the turning and shirring tube (2) by way of the fastening means (20) in the funnel-shaped region (12) . Finally, a "standing bubble" (21) and a pretreatment station (22) are shown, these being arranged outside the turning and shirring tube (2) upstream of the flexible tube inlet opening (5) .

The following examples are intended to explain the invention.

Examples

Inventive example 1:

A biaxially oriented, five-layer Walsroder K flex S plastic casing having a nominal caliber of 90 mm and a lay-flat width of 155 mm is coated contiguously from the outside with an approx. 10 μιη thick color layer composed of 30% by weight water, 65% by weight caramel (produced by Saba Muhle) and 5% by weight CMC and wound up again in the dried state. This roll is set up on the turning and shirring apparatus according to the invention. The end of the flexible tube is guided through the turning and shirring tube having an inside diameter of 40 mm, turned inside out, pulled back over the turning and shirring tube having an externally applied Teflon layer and an outside diameter of 54 mm and sealed off from the turning and shirring tube. The point at which the flexible tubular casing is turned does not directly adjoin the turning and shirring system, but is located at a spacing of approx. 300 mm upstream of 'the flexible tube outlet opening in the turning and shirring tube. After the pressure in the turning and shirring tube has been increased by 0.1 bar and the shirring system comprising two wheels has been switched on, the flexible tubular casing is pulled into the turning and shirring tube at a run-in speed of 85 m/min, is turned after leaving the turning and shirring tube until making contact with the rebounding wall and is pulled back again by the shirring system. While it is being pulled back, the flexible tubular casing is laid in pleats, that is to say shirred. During shirring, a flexible tubular casing length of 30 m is shirred to a shirred stick length of 410 mm. Inventive example 2:

A Walsroder FVP having a nominal caliber of 120 mm and a lay-flat width of 185 mm has, as external layer, an approx. 10 μπι PVDC coating film on the cellulose fibrous casing. A roll of this casing is set up on the turning and shirring apparatus according to the invention. The end of the casing is guided through the turning and shirring tube having an inside diameter of 60 mm, turned inside out, pulled back over the turning and shirring tube having an externally applied Teflon layer and an outside diameter of 71 mm and sealed off from the turning and shirring tube. After the pressure in the turning and shirring tube has been increased by 0.15 bar and the shirring system comprising two wheels has been switched on, the casing is turned at a run-in speed of 95 m/min and shirred to a casing length of 40 m to a shirred stick length of 410 mm. Comparative example 1 :

The casing from inventive example 1 is intended to be turned and simultaneously shirred on the same machine at an internal pressure of 0.02 bar. Although the internal pressure is high enough for the actual shirring process, the necessary advancement force for the turning process cannot be applied at this internal pressure. When the method has been started, the shirring system will immediately pull the turning point of the flexible tubular casing to the flexible tube outlet opening in the turning and shirring tube and interrupt the process for simultaneous turning and shirring, because no further length of flexible tube is pulled out of the turning and shirring tube. In this state, the applied layer is also easily damaged.

List of reference signs:

(1) Flexible tubular casing

(2) Turning and shirring tube

(3) Internal space

(4) Base

(5) Flexible tube inlet opening

(6) Flexible tube outlet opening

(7) Tubular region

(8) Apparatus means for shirring

(9} Apparatus means for shirring

(10 Compressed gas port

(11 Gas passage openings

(12 Funnel-shaped or tubular region

(13 Sealing means

(14 Rebounding wall

(15 Turning point of the emerging casing (1)

(16 Inside of the casing (1) before turning

(17 Outside of the casing (1) after turning

(18 Outside of the casing (1) before turning

(19 Inside of the casing (1) after turning

(20 Fastening means

(21 Standing bubble

(22 Pretreatment station