OF CAUL FAT FROM ANIMAL STOMACHS

The present invention relates to a system and a method for removal of caul fat from animal stomachs obtained during processing of carcasses. The system and method of the invention automatically remove caul fat from stomachs, and may be related to stomachs from any animal, and, more particularly, to larger animal such as pig, cattle, sheep and goat.

Background of invention

When animals such as pigs, cattle, sheep and goats are slaughtered, the stomachs may be trimmed for fat, rinsed, washed and salted before used, e.g. as casing for different types of sausages or for wrapping meat portions while cooking.

In the processing of an animal stomach, the caul fat is usually removed. Caul fat, also known as lace fat, mesentery, crepine, greater omentum, fat netting or just caul, is a thin web-like membrane, connected to the stomach at the Greater curvature, and the caul fat covers some of the internal organs in the live animal. When the stomach is isolated from the pluck set, the caul fat is connected to the stomach at the Greater curvature.

The caul fat is usually manually removed by an abattoir operator, and though the stomach from e.g. pigs have a weight of only 1.3 kg, the operator is handling, most frequently with one hand only, a big number of stomachs during a day, which results in monotonous repeated work, and the work is performed at a high speed, which may result in dilapidated employees.

The system described herein is a system capable of automatic removal of the caul fat from animal stomachs. The use of the system reduces the manual work for operators and hereby reduces physical disabilities of operators. More uniform trim of the treated stomachs is also obtained.

Summary of invention

The present invention relates to a system for automatic removal of caul fat from animal stomachs, where stomachs are manually fed onto a conveying bar, after which the system automatically determines the borderline between the animal stomach and caul fat, and automatically cuts off the caul fat from the animal stomach.

It its first aspect, the invention provides a system for automatic removal of caul fat from animal stomachs, which system may be characterised by comprising : a) a conveying bar or grippers on a conveyor for conveying an animal stomach with caul fat;

b) a measuring system for determining the borderline between the animal stomach and the caul fat; and

c) a first knife for cutting off caul fat from the animal stomach.

According to the invention, the system may further comprise a second knife for cutting off caul fat from the animal stomach, and/or a pre-cutting knife for pre-cutting the caul fat to a pre-determined length, before cutting off the remaining caul fat.

The measuring system of the invention, for determining the borderline between a stomach and the caul fat may be characterised by comprising :

a) a signal source capable of emitting a signal such as a light beam;

b) a sensor capable of obtaining a response by detecting the signal emitted from the signal source or capable of detecting a reflected signal based on the emitted signal;

c) a signal examiner capable of analysing the response optionally in respect to the emitted signal; and

d) a controller for controlling the position of the knife.

The measuring system may be based on a light beam such as a red LED, which is emitted towards the animal stomach with caul fat to be removed. The sensor may receive reflected light and a signal examiner may determine whether the light beam is located at the stomach or at the caul fat such as by determining the distance the light travels. The controller may receive such information and determine whether the knife should be adjusted upward, downward or not adjusted to cut off caul fat.

The system may be an automatic system, such that when a stomach is e.g. manually fed onto the conveying bar, a conveying guide for holding and guiding the animal stomach and/or a pulling guide may direct the stomach at the first knife for cutting off caul fat and optionally also past a knife for cutting open the stomach.

The invention also relates to a method for automatic removal of caul fat from animal stomachs, the method may comprise the subsequent steps of:

a) feeding animal stomachs with caul fat to a conveying bar on which the stomachs are conveyed or securing animal stomachs with caul fat to grippers on a conveyor;

b) automatically determining the borderline between the animal stomach and caul fat; and

c) automatically cutting off at least part of the caul fat from the animal stomach. One or more knives may be used to cut off caul fat from the animal stomach. Before cutting along the borderline between the stomach and caul fat the caul fat may be pre-cut to a pre-determined length.

According to the method of the invention, the borderline between the animal stomach and caul fat may be determined, and the caul fat may be removed by performing the subsequent steps of:

a) emitting a signal towards stomach with caul fat, for instance the signal is a light signal such as visible light, e.g. red light;

b) obtaining a response by detecting the emitted signal and/or detecting a reflected signal based on the emitted signal, or detecting an absence of an emitted signal or an absence of a reflected signal;

c) analysing the response optionally in relation to the emitted signal; and d) based on the analysis controlling the position of the knife in relation to the borderline between the animal stomach and caul fat, and hereby cutting off the caul fat substantially at the borderline between the stomach and the caul fat.

Cutting off caul fat substantially at the borderline between the stomach and the caul fat should be understood such that preferably the knife does not cut into the stomach making any openings in the stomach. Cutting at the borderline between the stomach and the caul fat may be at a location very close to the stomach and in the caul fat within e.g. 3 cm from edge of the stomach. Preferably the caul fat is cut within 2.5 cm from the edge of the stomach such as within 2 cm, e.g. within 1.5 cm, such as within 1 cm, e.g. within 0.5 cm.

The animal stomach may be manually fed onto a feeding tip on the conveying bar, the animal stomach may be fed onto the conveying bar by pulling the stomach opening from where the duodenum has been attached over an end of the conveying bar, pulling the stomach with the lesser curvature close to the conveying bar and in a part opposite the duodenum opening i.e. at a bulge in the Fundus part of the stomach making a perforation in the stomach such as by the tip of the conveying bar and pulling the stomach further onto the conveying bar such.

Brief description of figures

The present invention is further illustrated by reference to the accompanying drawing, in which:

Fig. 1 illustrates a stomach with caul fat;

Fig. 2 illustrates different sections of a system for automatic removal of caul fat from animal stomachs;

Fig. 3 illustrates a system for automatic removal of caul fat from animal stomachs; Fig. 4 illustrates part of a system for automatic removal of caul fat from animal stomach;

Figs. 5A and 5B illustrate a unit with a measuring system and a knife for cutting off caul fat; and

Figs. 6A and 6B illustrate some positions of a signal reflected from a stomach with caul fat.

Detailed description of the invention

At abattoirs, animal stomachs may be isolated from the pluck set and caul fat is usually connected to these stomachs. The caul fat is preferably removed before the stomachs are further treated and removal of the caul fat may be performed as described herein.

An aspect of the invention relates to a system for automatic removal of caul fat from animal stomachs, which system may be characterised by comprising :

• a conveying bar or a gripper on a conveyor for conveying the animal stomach with caul fat;

• a measuring system for determining the borderline between the animal stomach and caul fat; and

• a first knife for cutting off caul fat from the animal stomach.

The animal stomach which is treated as described herein is preferably obtained from animals where the stomach and/or the caul fat is used e.g. for food or feed, but also for non-edible products. The animals from where stomachs may be obtained may be selected from the group of pigs, cattle, sheep, deer, or goats, most preferably the stomachs are from pigs. Where different parts of a stomach are described herein these are related to pig stomachs, the skilled person knows how to convert this knowledge to stomachs from other animals where the stomachs may look different.

The conveying bar of the system is preferably for holding the stomachs during the process of cutting off caul fat, however the conveying bar may also be used for accumulating stomachs in a queue before these are being treated. The conveying bar may also direct stomachs from which caul fat is removed to a system where the stomachs are cut open. Such a system may be an integrated part of the system for automatic removal of caul fat.

The conveying bar may pass through a section for feeding animal stomachs onto the conveying bar (Section A, Fig. 2), a section for accumulating or lining up stomachs to be treated (Section B, Fig. 2), a section for pre-cutting caul fat

(Section C, Fig. 2), a section for cutting off caul fat (Section D, Fig. 2) and optionally a section for cutting open the stomachs (Section E, Fig. 2). Not all sections need be present in the system. Preferably a system comprises Section A and Section D.

An animal stomach isolated from the rest of the internal organs may be feed on the conveying bar by pulling the opening from where the duodenum has been attached over an end of the conveying bar, pulling the stomach with the lesser curvature close to the conveying bar and in a part opposite the duodenum opening i.e. at a bulge in the Fundus part of the stomach making a perforation in the stomach hereby making it possible for the stomach to hang and slide on the conveying bar. When hanging on the conveying bar a stomach has an overall shape which is convex or rounded downward from the conveying bar when observed in a side way direction and perpendicular to the transport direction of the stomach on the conveying bar. The main part of the caul fat that is the Greater omentum will hang below the rounded stomach if the stomach is positioned as described herein on the conveying bar.

The conveying bar is preferably circular when observed in a cross section and is preferably made of a hygienic material such as metal e.g. stainless steel which is easy to clean, and which does not corrode.

The conveying bar may also be a number of holding means capable of holding and conveying the stomachs, such holdings means may be clips or grippers secured to a conveyor and where the clips or grippers can hold stomachs along the Lesser curvature while conveying these while the caul fat is cut away and optionally also when the stomach is cut open. When using the term conveying bar herein this can be replaced by a gripper on a conveyor and the latter should be understood as incorporated it the term 'conveying bar'.

In the section for cutting off caul fat, a measuring system for determining the borderline between the animal stomach and caul fat may be present. The measuring system may use any measuring tools for determining the borderline between a stomach and a caul fat. Preferably the measuring tools do not have a physical contact with the stomach and/or caul fat, such tools may be based on waves such as electromagnetic waves, preferably electromagnetic waves which do not affect the stomachs to be treated or can be unsafe to use in areas where operators are working. The electromagnetic waves may be light e.g. visible light such as red light. The measuring tool may also be based on sound waves. The measuring system may be a vision system with a light emitter and a sensor which may be a camera.

A first knife for cutting off caul fat from the animal stomach may also be present in the section for cutting off caul fat. The first knife preferably meets the stomach which is under transport i.e. the first knife may be moved in the opposite direction of the stomachs under transport and the first knife follows the borderline between the stomach and the caul fat while cutting off the caul fat. The position of the first knife during cutting is determined due to the information obtained by the measuring system. However, the first knife need not to move in a horizontal direction i.e. opposite direction of the stomachs under transport while following and cutting along the borderline between a stomach and the caul fat. Though, preferably the first knife moves slightly forward i.e. in the opposite direction of the stomachs under transport when cutting the caul fat of a stomach, such as less than half the length of the stomach. When the first knife has finished cutting off caul fat it may return to a start position ready to cut off caul fat from another stomach under transport towards the first knife. Moving means is preferably connected to each knife or to a cutting unit comprising a knife. Such moving means is preferably capable of moving the knife fast and precisely to a determined position before, during and after the cutting process when cutting off caul fat.

The system described herein may further comprise a second knife for cutting off caul fat from the animal stomach and/or the system may comprise a pre-cutting knife for pre-cutting the caul fat to a pre-determined length to reduce the amount of caul fat hanging under a stomach under transport on the conveying bar.

A pre-cutting knife may be present in the section where the stomachs are lined up or in a further section denoted pre-cutting section, which may be located between the section where the stomachs are lined up and the section for cutting off caul fat. The pre-cutting knife need not to be movable during the handling of stomachs but may cut caul fat in a fixed position i.e. at a fixed distance below the conveying bar. The pre-cutting knife may thus pre-cut the caul fat to a pre- determined length. The cut may be substantially horizontal and need not follow the borderline between the stomach and the caul fat. The pre-determined length of caul fat may be e.g. 10-30 cm, such as 15-25 cm, e.g. about 20 cm.

A second knife may be present in the section for cutting off caul fat. This second knife may be located such that a stomach from where caul fat is to be cut off and which stomach is directed forward on the conveying bar passes by the second knife which then may catch up the stomach from behind and cut off the caul fat located at the rear part of the stomach under transport.

The measuring system, as mentioned above, may comprise:

• a signal source capable of emitting a signal;

• a sensor capable of obtaining a response by detecting the signal emitted from the signal source or capable of detecting a reflected signal based on the emitted signal; • a signal examiner capable of analysing the response optionally in respect to the emitted signal; and/or

• a controller for controlling the position of the knife.

The signal source of the measuring system may be light, such as light of green, blue or red colour, and the preferred light is LED light, such as red LED light, hereby the measuring system is preferably a light sensor system. The light may be emitted towards a stomach with caul fat under transport and/or treatment and may light up part of the stomach or part of the caul fat. The sensor may be located on the same side of the stomach as the signal source or on the other side of the product. Preferably the sensor is located at the same side of the stomach as the signal source.

When the sensor is located at the same side of the stomach as the signal source, the sensor may detect the signal reflected from the stomach such as light.

The signal examiner may analyse the response in respect of the emitted signal, e.g. reflected light in respect to emitted light, and the output from the analysis may be determining a distance such as a distance from the signal source to the part of the product illuminated by the light.

The controller may control the position of the knife to which the controller is connected. The control may be based on the knowledge of the distance from the signal source to the location of the cutting part of the knife when cutting off caul fat when the knife cuts at or below the borderline between the stomach and the caul fat. When a determined distance is equal to the known distance (a reference distance) from the signal source to the cutting part of the knife then it is known the knife cuts in the caul fat.

When the determined distance is shorter than the reference distance from the signal source to the cutting part of the knife then the knife is about to cut in the stomach, which is undesirable. The controller may hereby direct the knife position upwards when the signal examiner determines that the signal, e.g. a light, illuminates part of the caul fat and the controller may direct the knife position downwards when the signal examiner determines that the signal, e.g. a light, illuminates part of the stomach. The controller may be in contact with moving means moving the knife or cutting unit to a determined position. Moving means may be electrically activated or may be a servo system.

The system may further comprise one or more of different features which is further described below.

The conveying bar may have a feeding tip making it easier to feed stomachs on the conveying bar. Feeding stomachs onto the conveying bar may be performed manually by an operator. An operator may receive stomachs where the duodenum is removed and before feeding the stomach onto the conveying bar the operator may further remove the lesser momentum and optionally reduce the length of the gullet (Oesophagus) to 1-5 cm such as to about 2 cm, or the operator may receive stomachs ready to be feed onto the conveying bar.

A conveying guide may be present along part of the conveying bar, where the conveying guide is for holding and guiding the animal stomach along a part of the conveying bar and preferably past a first knife. Preferably the conveying guide is located above the conveying bar. The conveying guide may be located in the section where the caul fat is cut off by the first knife. Several conveying guides may be applied, e.g. 1-5 conveying guides, such as 2-4 conveying guides, which may hold and secure the conveying of a stomach. The conveying guides may hold a stomach such that the stomach part on the conveying bar is stretched out in the transport direction and the speed of the conveyor to which the conveying guides are attached may determine the transport speed of the stomach during the process where the caul fat is cut off and optionally also during a process where the stomach is cut open.

The conveying guide may be connected to and directed by a chain or conveyor which may be running in a loop. The loop may be located above the conveying bar and may pass the location of the section for cutting off caul fat and optionally also the section for cutting open the stomachs. If the loop pass the location of both mentioned sections the conveying guide may direct the stomach freed for caul fat to the stomach knife where the stomach is cut open.

A pulling guide may be present in the section for accumulating or lining up stomachs to be treated where the pulling guide may push or pull the animal stomach along a part of the conveying bar such as along the conveying bar until a pre-cutting section or until the section for cutting off caul fat. The pulling guide may be any types of guide capable of pushing and/or pulling stomachs along a conveying bar. The pulling guide may also be a conveying guide as described above and may be attached to the same conveyor as the conveying guides in the section for cutting off caul fat such that this conveyor is extended to at least be part of the section for accumulating or lining up stomachs to be treated. The pulling guide in form of a conveying guide may also be connected to a conveyor not being the conveyor with conveying guides in the section for cutting off caul fat.

The knife for cutting off caul fat is preferably a round knife with an outer cutting edge. The round knife for cutting off caul fat is preferably located horizontally. Any dimension of the round knife may be used such as a knife with a diameter of 5-15 cm. A knife cover may be present for covering each of the first knife and/or second knife and/or pre-cutting knife. The knife cover may surround the round knife except in a small area where the knife is capable of cutting off caul fat. The small area may be a slit which may be present in the knife cover such that the knife can get into contact with caul fat and cut off the caul fat. The knife cover may have fat guiding means extending towards the stomach when observed when the knife is in use, the fat guiding means may guide the caul fat towards the slit of the knife cover and further towards the knife where the caul fat is cut off.

Close to a knife, an exhaust tube for exhausting the cut off caul fat may be present. The exhaust tube may be one exhaust tube for each knife and may be located below the knife. The exhaust tube may be connected to the knife cover or to a knife assembly, the cutting unit, to secure exhaustion of cut off caul fat. In the cutting unit, a slit may be present in a screen in front of a part of the knife, this slit may secure only caul fat or material of a thickness corresponding to the width of the slit can get into contact with the knife. The exhaust tube may be connected to the cutting unit and when in function make an aspirating effect behind the screen hereby aspirating the caul fat through the slit and into the cutting unit and when the caul fat is cut off from the stomach the cut off caul fat can be aspirated into the tube and away from the system.

The system may also comprise a section for cutting open the stomach.

Such a section may comprise a stomach knife for opening the stomach. The stomach knife may be a round knife with an outer cutting edge, and which knife may be in a vertical position. Stomach knives and the function hereof are known in the art.

The knife for cutting off caul fat and the measuring system may be physically connected to each other and be a cutting unit i.e. a knife assembly and which can be moved together by the moving means. The moving means may be controlled by servo control or any other suitable controlling means, e.g. electricity. The servo control may direct the unit upward and downward and optionally also laterally.

Another aspect of the invention relates to a method for automatic removal of caul fat from animal stomachs, and the method may be characterised by comprising the subsequent steps of:

• feeding animal stomachs with caul fat to a conveying bar on which the stomachs are conveyed or securing animal stomachs with caul fat to gripping means such as grippers on a conveyor;

• automatically determining the borderline between the animal stomach and caul fat; and • automatically cutting off at least part of the caul fat from the animal stomach.

The method may further comprise cutting off substantially the remaining part of caul fat from the animal stomach, and/or pre-cutting the caul fat to a pre- determined length before cutting off the remaining part of the caul fat. With cutting off substantially the remaining part of caul fat from the animal stomach is meant that a first knife may not be able to cut off the caul fat along the entire borderline between the stomach and the caul fat, and a second knife may be used for cutting along the remaining part of the borderline and cutting off the remaining part of the caul fat from a stomach. In a preferred embodiment one knife cuts off the entire caul fat (greater omentum) or the entire of a pre-cut caul fat from a stomach.

The caul fat may also be pre-cut such that the caul fat is cut substantially to a pre-determined length. The caul fat may have a length of e.g. 80 cm, which may be pre-cut to a length of about 20 cm before cutting off the caul fat at the borderline between the stomach and the caul fat.

In the method, the borderline between the animal stomach and caul fat may be determined and the caul fat may be removed by performing the subsequent steps of:

• emitting a signal towards the stomach with caul fat, for instance the signal is a light signal such as visible light, e.g. red light;

• obtaining a response by detecting the emitted signal and/or detecting a reflected signal based on the emitted signal, or detecting an absence of an emitted signal or an absence of a reflected signal;

• analysing the response optionally in relation to the emitted signal; and

• based on the analysis controlling the position of the knife in relation to the borderline between the animal stomach and caul fat, and hereby cutting off caul fat substantially at the borderline between the stomach and the caul fat.

Further details of determining the borderline between the animal stomach and caul fat is described elsewhere herein.

When the caul fat is cut substantially at the borderline between the stomach and the caul fat, the knife preferably cuts only in the caul fat and/or where the caul fat is connected to the stomach. Preferably the knife dose not cut in the stomach tissue, hereby any possible material (e.g. feed) inside the stomach will preferably still be in the stomach when the caul fat is cut off.

The method may further comprise one or more feature as described herein.

The animal stomach may manually be fed onto a feeding tip on the conveying bar, or the animal stomach may be arranged such that grippers of a conveyor can grip the stomach in the Lesser curvature. If using a conveying bar, the animal stomach may be fed onto the conveying bar by pulling the opening of the stomach, where the duodenum is cut away, over the feeding tip, and aligning the Lesser curvature of the stomach along the conveying bar and pressing the feeding tip through the stomach in the Fundus part.

The animal stomach may be conveyed along the conveying bar, or may be conveyed by the conveyor with grippers, and at least part of the caul fat is cut off.

The cut off caul fat may be exhausted by an exhaust tube and directed to a caul fat storage. The caul fat may be used for e.g. food, feed or for biogas production.

Stomachs freed for the caul fat may be passed by a stomach knife for opening the stomach. Emptied stomachs may be further treated as known by the person skilled in the art.

Further details of the method may appear from the description of the function of the system as described herein.

A further aspect of the invention relates to use of the system as described herein for treating the animal stomach. The use of the system may be according to a method as described herein.

Detailed description of the figures

The invention may be further illustrated by reference to the accompanying drawing.

Fig. 1 illustrates a pig stomach (31) with caul fat (34). The stomach (31) has a Greater curvature (32) along which the caul fat (34) is attached at the borderline (33) between the animal stomach (31) and the caul fat (34). Opposite the Greater curvature (32) is the lesser curvature (35) between a part of the duodenum (36) and a part of the Oesophagus (37). Close to the Oesophagus (37) is the Fundus (38).

Fig. 2 illustrates different possible sections of a system (1) for automatic removal of caul fat from animal stomachs. Section A: Section for feeding animal stomachs onto the conveying bar; Section B: Section for accumulating or lining up stomachs to be treated; Section C: Pre-cutting section; Section D: Section for cutting off caul fat; Section E: Section for cutting open the stomachs. Not all sections need be present in a system (1) for automatic removal of caul fat from animal stomachs, e.g. section B and/or section C and/or section E may be omitted from the system (1). Thus, a system (1) preferably comprises section A and section D. The system may also comprise e.g. section A, Section C and section D or section

A, Section C, section D and section E or section A, section D and section E. Fig. 3 illustrates a system (1) for automatic removal of caul fat (34) from animal stomachs (31). The illustrated system (1) comprises a conveying bar (2) with a feeding tip (10) for feeding stomachs (31) into the system (1). A pulling guide (11) pulls the stomachs one at a time towards the conveying guide (14). The pulling guide (11) travels forward and backward in the system (1) in a travelling rail (12). The conveying guide (14) is driven by a chain or conveyor (13) around wheels (15) with teeth and a roller (21). The conveying guide (14) guides stomach past cutting units (5) with a measuring system (not shown) and a second knife (6) (this unit is illustrated by '5(w6)') or a first knife (4) (this unit is illustrated by '5(w4)')· A pre-cutting knife (not shown) may be located in Section C (Fig. 2) i.e. between the indicated position of the pulling guide (11) and the cutting unit (5) with the second knife (5(w6)). The cutting units (5) may also include a signal source (not shown) and a sensor (not shown). The cutting units (5) are each operated by individual systems comprising a number of moving means (16) e.g. two moving means (16) for each cutting unit (5). Stomachs (31), from which caul fat (34) is cut away, may continue on the conveying bar (2) into a section of the system (1) (Section E, Fig. 2) where the correct position of the stomach (31) is secured by two rollers (22 - one roller is hidden behind the indicated roller) and the stomach is opened by a stomach knife (17). A stomach opener (18) secure the two half parts of the opened stomach (31) is directed past the stomach knife (17) and to a stomach delivery guide (20) guiding the stomach out of the system (1). Below the stomach knife (17) is a box for stomach contents (19) which may catch the stomach contents which leave the stomachs during the opening process. The system (1) has a frame (23) securing space for the pulling guide (11) to travel forward and backward and to the movements performed by one or more cutting units (5) e.g. including a pre-cutting unit (not shown). In the figure a stomach (31) is illustrated hanging on the conveying bar (2) and with the caul fat (34) below the stomach (31). The pulling guide (11) pulls the stomach (31) from the feeding tip (10) towards the conveying guides (14). At the illustrated stage the caul fat (34) in not cut such as with a pre-cutting knife (not shown).

Fig. 4 illustrates the main parts of Section D and E (see Fig. 2) of the system (1) for automatic removal of caul fat from animal stomachs. The section D

(section for cutting off caul fat) is illustrated with two cutting units (5) for cutting off caul fat and the section E (section for cutting open the stomachs) is illustrated with a stomach knife (17). Most of the features are described in respect of Fig. 3.

Also illustrated is the driving direction (24) of the chain or conveyor (13) which conveys the conveying guides (14). The cutting unit indicated with '5(w6)' is a cutting unit (5) with a second knife (6) and this unit need not to be present in the system (1), but if present may increase the amount of caul fat removed from treated stomachs. The unit '5(w6)' registers when a stomach has passed the unit (5(w6)) and cuts caul fat from the rear end of the stomach under transport where the unit (5(w6)) follows the stomach in the same direction as the stomach is transported and at the same time the unit (5(w6)) cuts away a part of the caul fat by cutting from the Fundus area of the stomach towards the larger curvature if the stomach is arranged on the conveying bar by first pulling the duodenum-opening over the feeding tip of the conveying bar. The other cutting unit (5) indicated with '5(w4)' is under operation of the system (1) positioned in front of a stomach under transport and just at the side of the V-form (beneath the roller (21)) of the conveying bar (2) where a stomach during its transport starts to increase from the bottom part of the V-form (at the right side of the V-formed part in Fig. 4) hereby the caul fat which is connected to the stomach at the Greater curvature close to the duodenum is directed towards the knife (4) of the cutting unit (5) where a signal source and a sensor located at the cutting unit (5) will obtain data of the stomach and a processor controls the cutting unit (5) by moving means (16) to guide the knife (4) along the Greater curvature of the stomach and hereby the knife (4) cuts along the borderline between for the stomach and the caul fat. The cutting unit (5(w4)) will follow the shape of the larger curvature downwards and up towards the fundus area and cuts off the caul fat with the knife (4). During cutting the cutting unit (5(w4)) may have passed the V-formed part of the conveying bar (2) and when a stomach has passed the cutting unit (5(w4)) this cutting unit (5) will return to its start position, which may be a location just after the conveying bar (2) starts to increase after the V-formed part of the conveying bar (2). However, the conveying bar (2) need not to be V-formed, it can also be e.g. straight.

Fig. 5 illustrates a cutting unit (5) with a measuring system (3) and a knife (4 or 6) for cutting off caul fat. In Fig. 5A the cutting unit (5) is illustrated from below and towards a slit (25) into which the caul fat is aspirated and cut off by a knife (4 or 6). The cutting unit (5) comprises a motor (27) for driving the knife (4 or 6), a screen (26) screening off a volume with connection to a tube (28) making a vacuum under operation to aspirate the caul fat through the tube (28). Also shown is a measuring system (3) making e.g. a light beam (30) used to determine the distance to the stomach or caul fat. The cutting unit (5) may be connected by a holder (29) e.g. to moving means such as a servo system controlling the movements of the cutting unit (5). In Fig. 5B the cutting unit (5) is illustrated from above and towards the measuring system (3). The measuring system (3) makes e.g. a light beam (30) directed towards the slit (25) where the borderline between the stomach and the caul fat is directed past when the cutting unit is in function. The measuring system (3) determines the distance to the stomach or caul fat based on the emitted light beam (30) and a reflected light beam retrieved by the measuring system (3). The determined distance is used to determine whether the cutting unit (5) should be moved and in which direction. The holder (29) connects the cutting unit (5) to moving means e.g. a servo system operating the cutting unit (5). The cutting unit (5) is operated such that the knife (4 or 6) cuts off the caul fat which is aspirated through the slit (25) and further away by a tube (28). The knife is driven by a motor (27).

Fig. 6 illustrates some different signal positions (39) of a signal reflected from a stomach (31) with caul fat (34) which stomach (31) is positioned on a conveying bar (2). The figure is only illustrative for a few different signal positions (39), preferably when the system is in function only one signal and the

corresponding signal are analysed at a time i.e. one signal position (39) is observed when the system is in function. Light may be the used signal. In the figures, the light signals correspond to the location where the light hits the stomach (31) or caul fat (34), and from where an emitted light signal is reflected, i.e. the signal source and the sensor are located at the same side of the stomach. In Fig 6A the illustrated signal positions (39) indicate light signals and the corresponding emitted light signal positioned at the stomach (the uppermost signal position (39)) or just at the borderline between the stomach and the caul fat (the lowermost signal position (39)). In such situations, the position of the knife may be adjusted downward not to cut into the stomach (31), but only in the caul fat (34) below the stomach (31), or the lowermost signal position (39) may indicate the knife is cutting just below the borderline between the stomach (31) and the caul fat (34), and no adjustment of the knife is needed. In Fig 6B the illustrated signal positions (39) are located at the caul fat (34). The uppermost of the signal positions (39) may indicate the knife will cut just below the borderline between the stomach (31) and the caul fat (34) and the lowermost of the signal positions (39) may indicate the knife will cut too far away from the borderline between the stomach (31) and the caul fat (34) and thus the knife will be adjusted to cut closer to the borderline between the stomach (31) and the caul fat (34).

Examples

The system as illustrated in the figures has been tested for automatic removal of caul fat from animal stomachs obtained from pigs with a slaughter weight of about 80 kg. The pigs were slaughtered at a Danish abattoir and the stomachs were released for the duodenum and the lesser omentum and the gullet/oesophagus was cut to a length of about 2 cm. The stomachs were fed onto a conveying bar and pulled/pushed along the section for accumulating or lining up stomachs to be treated. In the section for cutting off caul fat the stomachs were secured by conveying guides on a conveyor which guided the stomachs through the section for cutting off caul fat. A unit was used which comprised a first knife connected to a measuring system based on light, and which determined the distance from the sensor to the object to be treated and based on these distance determinations the unit was directed upward, downward or straight forward by a servo control connected to the unit to cut off the caul fat substantially at the borderline between the stomach and the caul fat.

The system handled about 1,000 stomachs per hour and the result was highly improved compared to the manual treatment of the stomachs.

List of reference signs

In the figures, identical structures, elements or parts that appear in more than one figure are generally labelled with the same numeral in all the figures in which they appear.

1. System

2. Conveying bar

3. Measuring system

4. First knife

5. Cutting unit

6. Second knife

7. Pre-cutting knife

8. Signal source

9. Sensor

10. Feeding tip

11. Pulling guide

12. Travelling rail

13. Chain or conveyor for directing conveying guide

14. Conveying guide

15. Wheel

16. Moving means

17. Stomach knife

18. Stomach opener

19. Box for stomach contents

20. Stomach delivery guide

21. Roller

22. Roller 23. Frame

24. Running direction of travelling rail

25. Slit

26. Screen

27. Motor for driving a knife

28. Tube

29. Holder

30. Light beam

31. Stomach

32. Greater curvature

33. Borderline between Greater curvature and caul fat

34. Caul fat

35. Lesser curvature

36. Duodenum

37. Oesophagus

38. Fundus