Field of invention

The present invention relates to a detection unit and a method for de- tecting a leakage hole in an intestine that is processed while being sus- pended on an electrically conducting tubular member.

Prior art

To determine the quality and to cut the carcass into valuable parts of meat, the examination and processing devices are controlled relative to the location of anatomical parts of the carcass. Intestines from the ani- mals are processed in a similar way, and e.g. natural casings are of ma- jor interest.

Processing of intestines from the animals involves several steps includ- ing cleaning the intestines, scraping of the inner wall of the intestines to remove the mucous layer and scraping of the outer part of the intes- tines. An additional step of measurement is carried out in order to pack the intestines according to their size and quality. In the step of meas- urement, the diameter of each intestine is detected so that the diame- ter can be used to classify the intestine and to cut the intestine into pieces based on the diameter along the length of the intestine.

Detection of holes in an intestine is essential when establishing the quality of the intestine. Therefore, several methods for identifying holes in an intestine that is suspended on a tubular member have been de- veloped. Some of the prior art methods are based on optical detection of the hole. An optical detection can be accomplished by using optical sensors such as a camera. The use of cameras is, however, associated with several disadvantages.

First of all, several cameras are required in order to cover all sides of the intestine. Moreover, since insufficient lighting may make it impossi- ble to apply the cameras, a complex and expensive lighting is typically required. Furthermore, water from the intestine may splash on the cameras so that the water has to be wiped off in order to maintain a high camera data quality.

Therefore, it would be an advantage to be able to provide an alternative way of identifying holes in an intestine that is suspended on a tubular member.

It is an object of the present invention to provide an alternative method for identifying holes in an intestine that is suspended on a tubular member.

It is also an object of the present invention to provide a detection unit for identifying holes in an intestine that is suspended on a tubular member.

Summary of the invention

The object of the present invention can be achieved by a detection unit as defined in claim 1 and by a method as defined in claim 9. Preferred embodiments are defined in the dependent subclaims, explained in the following description and illustrated in the accompanying drawings.

The detection unit according to the invention is a detection unit config- ured to detect a leakage hole in an intestine suspended on a tubular member having a perforated portion that is configured to distribute a flow of liquid through the perforated portion and hereby pressurise the intestine, when the intestine is being moved with a non-zero velocity along the longitudinal axis of the tubular member, wherein the detec- tion unit comprises:

- an electrically conducting and axially extending sleeve-shaped sur- rounding portion that at least partly surrounds the circumference of the tubular member;

- an electric circuitry arranged and configured to measure an electric quantity which is established between the surrounding portion and the liquid pressurising the intestine. Hereby it is possible to provide a detection unit that makes it possible to identify holes in an intestine that is suspended on a tubular member in a reliable and easy manner.

In one embodiment, the tubular member is an electrically conducting tubular member. In one embodiment, the tubular member is rod- shaped member made of a metal.

If the tubular member is not electrically conducting, electric circuitry may be configured to measure an electrical quantity between the sur- rounding portion and a contact structure (e.g. an anode) being electri- cally connected to the liquid.

By providing an electrically conducting and axially extending sleeve- shaped surrounding portion that at least partly surrounds the circum- ference of the tubular member it is possible to measure an electric quantity which is established between the surrounding portion and the liquid pressurising the intestine.

The electric circuitry is arranged and configured to measure an electric quantity which is established between the surrounding portion and the liquid pressurising the intestine.

In one embodiment, the electric circuitry is arranged and configured to measure an electric quantity which is established between the sur- rounding portion and the tubular member.

In one embodiment, the electric quantity is the electric resistance.

In one embodiment, the electric quantity is the electric current.

In one embodiment, the electric quantity is the electric voltage.

Since the intestine is pressurised, there will be a jet of water when a portion of the pressurised intestine comprises a hole. When a portion of an intestine that comprises a hole passes the surrounding portion, the jet of water will extend between and thus connect the water inside the intestine and the surrounding portion. Accordingly, the electrical re- sistance is decreased compared to the situation, in which the water in- side the intestine and the surrounding portion is separated solely by the intestine and the surrounding air. Accordingly, by measuring the current or the resistance between the surrounding portion and the tubular member, it is possible to detect if the intestine comprises a hole that passes the surrounding portion.

The velocity is typically in the range 0.5-3 m/s.

In one embodiment, the velocity is in the range 1-2.5 m/s.

In one embodiment, the perforated portion is formed as a plurality of holes (through bores) in the radial surface of the tubular member.

In one embodiment, the perforated portion is formed as one or more slots provided in the radial surface of the tubular member.

In one embodiment, at least a portion of the tubular member is formed as a pipe.

In one embodiment, the distance D between the surrounding portion and the tubular member is selected in dependency of the type of intes- tine.

In one embodiment, the distance is within the range 20-50 mm if the intestine is from a pig. The term pig includes hogs and swine.

In one embodiment, the distance is within the range 10-40 mm if the intestine is from a sheep. In one embodiment, the distance is within the range 25-70 mm if the intestine is from cattle. The term "cattle" includes "livestock".

The tubular member is narrow enough to be able to receive the smallest intestinal having a diameter D _min . The surrounding portion may be shaped as a sensor ring.

The surrounding portion is large enough to ensure that there is always air between the intestine and the surrounding portion, even at the larg- est intestinal diameter D _max the processing unit is intended for. Accord- ingly, the ring must always be at least (D _max - D _min ) larger than the di- ameter than the tubular member.

Accordingly, the distance D between the surrounding portion and the tubular member distance must fulfil the following equation (A):

(A) D ≥ D _max - D _min

The detection unit will also work if the distance D is greater. It is just more likely that the water jet will break before it reaches the surround- ing portion.

It may be an advantage that the surrounding portion comprises a first part and a second part, wherein the first part and a second part are movably arranged relative to each other.

In one embodiment, the surrounding portion comprises two identical parts.

In one embodiment, the two parts are semi-cylindrical.

In one embodiment, the surrounding portion comprises two parts that are electrically connected to each other. In one embodiment, the surrounding portion is a one-piece body.

In one embodiment, the one-piece body is cylindrical.

In one embodiment, the surrounding portion extends along at least 180 degrees of the circumference of the tubular member.

It may be advantageous that the electric circuitry is electrically con- nected to a first contact point being electrically connected to the liquid (when the tubular member has filled liquid into the intestine) and to the surrounding portion in a second contact point that is electrically isolated from the liquid.

It may be an advantage that the surrounding portion is made in metal.

In one embodiment, the surrounding portion is made in stainless steel.

It may be beneficial that the surrounding portion extends along at least 355 degrees of the circumference of the tubular member.

In one embodiment, the surrounding portion extends along 360 degrees of the circumference of the tubular member.

In one embodiment, the electric circuitry is configured to detect when the electrical quantity between the surrounding portion and the liquid pressurising the intestine is not within a predefined interval (below a predefined level if the electrical resistance is measured or above a pre- defined level if the current is measured) for a time period being longer than a predefined non-zero time. Hereby, it is possible to avoid a false alarm.

In one embodiment, the electric circuitry is configured to detect when the electrical quantity between the surrounding portion and the tubular member is not within a predefined interval (below a predefined level if the electrical resistance is measured or above a predefined level if the current is measured) for a time period being longer than a predefined non-zero time. Hereby, it is possible to avoid a false alarm.

In one embodiment, the electric circuitry is configured to detect when the electrical current between the surrounding portion and the liquid pressurising the intestine is below a predefined level (this is relevant if the electrical resistance is measured) for a time period being longer than a predefined non-zero time.

In one embodiment, the electric circuitry is configured to detect when the electrical current between the surrounding portion and the tubular member is below a predefined level (this is relevant if the electrical re- sistance is measured) for a time period being longer than a predefined non-zero time.

In one embodiment, the electric circuitry is configured to detect when the electrical current between the surrounding portion and the tubular member is above a predefined level (this is relevant if the current is measured) for a time period being longer than a predefined non-zero time.

In one embodiment, the electric circuitry is configured to detect when the electrical current between the surrounding portion and the liquid pressurising the intestine is above a predefined level (this is relevant if the current is measured) for a time period being longer than a prede- fined non-zero time.

In one embodiment, the predefined resistance level is 10 MΩ or less. Testing has revealed that this resistance level is suitable in order to avoid a false alarm.

It may be an advantage that the predefined time T' is selected in de- pendency of the length L of the surrounding portion and the velocity V in such a manner that:

In one embodiment, the predefined time T' is selected in dependency of the length L of the surrounding portion and the velocity V in such a manner that:

In one embodiment, the predefined time T' is selected in dependency of the length L of the surrounding portion and the velocity V in such a manner that:

In one embodiment, the predefined time T' is at least 3 ms.

In one embodiment, the predefined time T' is at least 5 ms.

In one embodiment, the predefined time T' is at least 8 ms.

In one embodiment, the predefined time T' is at least 10 ms.

In one embodiment, the predefined time T' is at least 25 ms.

In one embodiment, the predefined time T' is at least 50 ms.

In one embodiment, the processing unit comprises a chassis.

To prevent a liquid film from creating a false electrical connection from the surrounding portion to the machine chassis, it may be advanta- geous to place an electrically conductive structure (e.g. a plate) be- tween the chassis of the processing unit and the surrounding portion. This electrically conductive structure will be electrically isolated from both the chassis and the surrounding portion, and an electrical circuit ensures that the voltage on this electrically conductive structure is at all times the same as the voltage on the surrounding portion.

Since any liquid film that may lie between the surrounding portion and the chassis must pass over the electrically conductive structure, it is not possible for any current to flow from the surrounding portion to the chassis because there is no voltage potential between the surrounding portion and the electrically conductive structure.

If an electrical current flows between the electrically conductive struc- ture the chassis, this current will not affect the measurement of electri- cal quantities between the surrounding portion and the fluid inside the intestine.

The method according to the invention is a method for detecting a leak- age hole in an intestine that is suspended on a tubular member having a perforated portion that is configured to distribute a flow of liquid through the perforated portion and hereby pressurise the intestine, when the intestine is being moved with a non-zero velocity along the longitudinal axis of the tubular member, wherein the method comprises the following steps:

- arranging an electrically conducting and axially extending sleeve- shaped surrounding portion in such a manner that the surrounding portion at least partly surrounds the circumference of the tubular member and

- measuring the electrical quantity between the surrounding portion and the liquid pressurising the intestine.

Hereby, it is possible, to identify holes in an intestine that is suspended on a tubular member in a reliable and easy manner.

In one embodiment, the tubular member is an electrically conducting tubular member.

If the tubular member is not electrically conducting, the electrical quan- tity between the surrounding portion and the liquid pressurising the in- testine can be measured between the surrounding portion and a contact structure (e.g. an anode) being electrically connected to the liquid. It may be advantageous that the method comprises the step of arrang- ing the tubular member in such a manner that the distance between the surrounding portion and the tubular member is selected independently of the type of intestine, wherein the distance is: a) within the range 20-50 mm if the intestine is from a pig; b) within the range 10-40 mm if the intestine is from a sheep and c) within the range 25-70 mm if the intestine is from cattle.

Hereby, the optimum setup can be achieved.

It may be an advantage that the surrounding portion comprises a first part and a second part, wherein the first part and the second part are movably arranged relative to each other. Hereby, insertion of the intes- tine through the surrounding portion can be eased.

It may be an advantage that the method comprises the step of applying a surrounding portion that is formed as a one-piece body.

In one embodiment, the method comprises the step of applying a sur- rounding portion that extends along at least 180 degrees of the circum- ference of the tubular member.

In one embodiment, the method comprises the step of applying a sur- rounding portion that extends along at least 355 degrees of the circum- ference of the tubular member.

In one embodiment, the method comprises the step of applying a sur- rounding portion that extends at least along 358 degrees of the circum- ference of the tubular member.

In one embodiment, the surrounding portion extends along 360 degrees of the circumference of the tubular member.

It may be an advantage that the method comprises the step of applying an electric circuitry that is configured to detect when the electrical quantity between the surrounding portion and the liquid (when the tub- ular member has filled liquid into the intestine) is below a predefined level (this is relevant if the electrical resistance is measured) or above a predefined level (this is relevant if the current is measured) for a time period being longer than a predefined non-zero time T'. Hereby, a false alarm can be avoided in case that there is an electrical connection through water between the surrounding portion and the tubular mem- ber for a short time period where there is no hole in the intestine.

It may be advantageous that the method comprises the step of applying an electrical resistance as the electrical quantity, wherein the prede- fined resistance level is 10 MΩ or less.

It may be an advantage that the method comprises the step of applying a predefined time T' that is selected in dependency of the length L of the surrounding portion and the velocity V in such a manner that

It may be an advantage that the method comprises the step of applying a predefined time T' that is selected in dependency of the length L of the surrounding portion and the velocity V in such a manner that

It may be an advantage that the method comprises the step of applying a predefined time T' that is selected in dependency of the length L of the surrounding portion and the velocity V in such a manner that

It may be beneficial to have a processing unit for processing an intes- tine having an open end, wherein the processing unit comprises:

- a tubular member having a perforated portion that is configured to distribute a flow of liquid through the perforated portion, wherein the tubular member is configured to receive the open end of the intestine and suspend the intestine on the tubular member and hereby pres- surise the intestine;

- two drive rollers comprising circumferential track configured to en- gage with the tubular member, where at least one of the drive rollers are arranged and configured to move the intestine with a non-zero velocity along the longitudinal axis of the tubular member;

- two clamping rollers arranged to be brought into a clamping configu- ration, in which the intestine is clamped by the clamping rollers, wherein the distal end of the tubular member is arranged between the drive rollers and the clamping rollers, wherein the processing unit comprises a detection unit according to the invention.

Hereby, it is possible to provide a processing unit that is capable of pro- cessing an intestine and at the same time detecting holes in the intes- tine in a fast and reliable manner.

In one embodiment, the tubular member is electrically conducting.

It may be an advantage that the detection unit is arranged between the drive rollers and the clamping rollers.

The intestine detector according to the invention comprises a first end detector and a second end detector arranged in a non-zero distance from the first end detector, wherein the intestine detector comprises an intermediate detector arranged and distanced between each of the end detectors in such a configuration that the intermediate detector will be electrically connected to any intestine suspended on the end detectors and extending between the first end detector and the second end detec- tor.

Hereby, it is possible to measure an electrical quantity between the end detectors and the intermediate detector in order to detect if an intestine is suspended on the intestine detector. In one embodiment, the intestine detector comprises an electrical cir- cuitry configured to detect the electrical resistance between any of the end detector and the intermediate detector.

In one embodiment, the intestine detector comprises an electrical cir- cuitry configured to detect the electrical current between any of the end detector and the intermediate detector.

In one embodiment, the intestine detector comprises an electrical cir- cuitry configured to detect the electrical potential difference between any of the end detector and the intermediate detector.

In one embodiment, each of the end detectors are shaped to receive and maintain an intestine suspended on the end detector.

In one embodiment, the end detectors have the same geometric form.

In one embodiment, the end detectors comprise a hook-shaped portion. Hereby, the end detectors can receive and maintain an intestine sus- pended thereon.

In one embodiment, the intermediate detector has a straight distal por- tion extending between the first end detector and the second end de- tector.

In one embodiment, the end detectors and the intermediate detector are made in metal.

In a preferred embodiment, the end detectors and the intermediate de- tector are made in stainless steel.

In one embodiment, the end detectors extend through a mounting box that comprises electrical connection structures for connecting an electric circuitry configured to perform one of more electrical measurements by means of the detectors.

In one embodiment, the intestine detector comprises two equally shaped receiving portions each comprising a set of detectors and an intermediate detector arranged therebetween.

In one embodiment, the intestine detector is electrically insulated by means of insulators from the wall onto which the intestine detector is attached.

In one embodiment, the intestine detector comprises an electrical cir- cuitry that is equal to the electrical circuitry that the detection unit ac- cording to the invention comprises.

In one embodiment, the intestine detector and the detection unit ac- cording to the invention uses the same electrical circuitry.

Description of the Drawings

The invention will become more fully understood from the detailed de- scription given herein below. The accompanying drawings are given by way of illustration only, and thus, they are not limitative of the present invention. In the accompanying drawings:

Fig. 1 shows a schematic, perspective, cross-sectional view of a detection unit according to the invention;

Fig. 2 shows a schematic, cross-sectional side view of the detec- tion unit shown in Fig. 1;

Fig. 3 shows a schematic side view of a processing unit according to the invention;

Fig. 4 shows a schematic side view of the processing unit shown in Fig. 3 in another configuration;

Fig. 5 shows a graph depicting the electrical resistance as a func- tion of time;

Fig. 6 shows a schematic view of a detection device according to the invention; Fig. 7 shows a perspective view of a detection unit according to the invention;

Fig. 8 shows a side view of a tubular member having a distal end that is arranged between a set of drive rollers and a set of clamping rollers (as the one shown in Fig. 7);

Fig. 9 shows an intestine detector according to the invention;

Fig. 10 shows a perspective side view of the intestine detector shown in Fig. 9;

Fig. 11 shows an intestine detector according to the invention and

Fig. 12 shows a perspective side view of the intestine detector- shown in Fig. 11.

Detailed description of the invention

Referring now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention, a cross-sectional view of a detection unit 2 according to the invention is illustrated in Fig. 1.

The detection unit 2 comprises an electrically conducting and axially extending sleeve-shaped surrounding portion having a first part 4 and a second part 4'. Each part 4, 4' is semi-circular and extends along 180 degrees of the circumference of an electrically conducting tubular mem- ber 10. The tubular member 10 is formed as a pipe that is centrally ar- ranged in the surrounding portion and extends axially along the longitu- dinal axis of the surrounding portion.

An intestine 8 is suspended on the tubular member 10. The tubular member 10 has a perforated portion that is configured to distribute a flow of liquid 6 through the perforated portion and hereby pressurise the intestine 8. The intestine 8 is being moved with a non-zero velocity V along the longitudinal axis of the tubular member 10.

The detection unit 2 is configured to detect if there is a leakage hole 12 in the intestine 8. Since the intestine 8 is pressurised, there is a jet of water 6. The jet of water 6 extends between the water inside the intes- tine 8 and the first part 4 of the surrounding portion.

The jet of water 6 establishes an electrical connection between the tubular member 10 and the first part 4 of the surrounding portion. Ac- cordingly, the electrical resistance is decreased compared to the situa- tion, in which the water inside the intestine 8 and the surrounding por- tion is separated solely by the intestine 8 and the surrounding air.

The detection device 2 comprises an electric circuitry (not shown) ar- ranged and configured to measure an electric quantity such as the elec- trical resistance or the electrical current between the surrounding por- tion and the tubular member 10. Therefore, the detection unit 2 makes it possible to measure when there is a shift in the current or the re- sistance between the surrounding portion and the tubular member 10. When a shift occurs, the detection unit has detected that the intestine 8 comprises a leakage hole 12 that passes the surrounding portion.

The length L of the surrounding portion is indicated. Since the intestine 8 is moving with the velocity V the leakage hole 12 will move with the same velocity V relative to the surrounding portion. Thus, the expected contact time tcontact at which the jet of water 8 will establish an electrical contact between the tubular member 10 and the surrounding portion can be calculated by using the following equation:

(1) T _contact = L/V

In order to avoid a false alarm, the electric circuitry may be configured to detect when the electrical quantity between the surrounding portion and the tubular member 10 is below a predefined level (this is relevant if the electrical resistance is measured) or below a predefined level (this is relevant if the current is measured) for a time period being longer than a predefined non-zero time. Hereby, it is possible to avoid a false alarm. In one example the velocity V is 2 m/s and L is 10 cm. By using equa- tion (1) one can calculate that:

(2) T _contact = L/V = (0.10 m)/(2 m/s) = 0.05 s = 50 ms.

With these parameters, one may define that a leakage hole 12 is de- tected when a reduced electric resistance is below 10 MΩ for a time pe- riod in the range 10-50 ms.

Fig. 2 illustrates a schematic, cross-sectional side view of the detection unit 2 shown in Fig. 1. The first part 4 and the second part 4' of the sur- rounding portion of the detection unit 2 have a semi-circular cross sec- tion. The tubular member 10 has a plurality of perforations 28. The wa- ter inside the tubular member 10 is pressurised. Accordingly, the water flows through the perforations 28 and pressurises the intestine 8.

A jet of water 6 extends between the leakage hole 12 and the surround- ing portion. The distance D between the tubular member 10 and the surrounding portion 10 is indicated.

Fig. 3 illustrates a processing unit 20 according to the invention in a first configuration, wherein Fig. 4 illustrates the processing unit 20 shown in Fig. 3 in a second configuration. The processing unit 20 is de- signed for processing an intestine 8 having an open end. The processing unit 20 comprises an electrically conducting tubular member 10 having a perforated portion that is configured to distribute a flow of liquid (such as water) through the perforated portion.

The tubular member 10 is arranged and configured to receive the open end of the intestine 8 and hereby allow the intestine 8 to be suspended on the tubular member 10 and hereby pressurise the intestine 8 with the liquid.

The processing unit 20 comprises two drive rollers 24. At least one of the drive rollers 24 comprises a circumferential track configured to en- gage with the tubular member 10.

At least one of the drive rollers 24 are arranged and configured to move the intestine 8 with a non-zero velocity V along the longitudinal axis of the tubular member 10.

In a preferred embodiment, the drive rollers 24 are shaped in the same way so that both drive rollers 24 comprise a circumferential track con- figured to engage with the tubular member 10.

The processing unit 20 comprises two clamping rollers 26 arranged to be brought into a clamping configuration, in which the intestine 8 is clamped by the clamping rollers 26.

The distal end of the tubular member 10 is arranged between the drive rollers 24 and the clamping rollers 26. The processing unit 20 comprises a detection unit 2 according to the invention. The detection unit 2 is arranged between the drive rollers 24 and the clamping rollers 26.

Each of the clamping rollers 26 is partly covered by a screen 36. The screen 36 may preferably be made in a non-conducting material (e.g. a plastic material). The detection unit 2 is configured to detect a leakage hole in an intestine 8 suspended on the tubular member when the in- testine 8 is being moved with a non-zero velocity V along the longitudi- nal axis of the tubular member 10. The detection unit 2 comprises an electrically conducting and axially extending sleeve-shaped surrounding portion 4, 4' that is configured to be brought into a configuration (as shown in Fig. 4), in which the surrounding portion surrounds the cir- cumference of the tubular member 10.

The detection unit 2 comprises an electric circuitry 14 arranged and configured to measure an electric quantity such as the electric re- sistance or the electric current which is established between the sur- rounding portion and the tubular member 10. It can be seen that the electric circuitry 14 is electrically connected to the tubular member 10 and to the surrounding portion by wires 22, 22'. Moreover, the tubular member 10 is fixed to a bracket 16 that is electrically connected to electrical ground G.

The lowermost drive roller 24 and the lowermost clamping roller 26 are slidably mounted on a slide rod 18 for allowing an easy adjustment of the horizontal position of the rollers 24, 26.

In Fig. 3 an intestine 8 is suspended on an intestine detector 38 accord- ing to the invention. The intestine detector 38 comprises a first end de- tector 40 and a second end detector 40' arranged in a non-zero dis- tance from the first end detector. The intestine detector 38 comprises an intermediate detector 42 arranged and distanced between each of the end detectors 40, 40' in such a configuration that the intermediate detector 42 will be electrically connected to any intestine suspended on the end detectors 40, 40' and extending between the first end detector 40 and the second end detector 40'.

Each of the end detectors 40, 40' are shaped to receive and maintain an intestine suspended on the end detector 40, 40'. The end detectors 40, 40' have the same geometric form. The end detectors 40, 40' comprise a hook-shaped portion. The intermediate detector, however, has a straight distal portion extending between the first end detector 40 and the second end detector 40'.

The end detectors 40, 40' extend through a mounting box that compris- es electrical connection structures for connecting an electric circuitry configured to perform one or more electrical measurements by means of the detectors 40, 40', 42.

The intestine 8 is received by the tubular member 10 and is suspended thereon. Furthermore, the intestine 8 is pressurised and thus inflated by water from the tubular member 10. The intestine 8 is clamped between the clamping rollers 26 in a first position of the intestine 8 and by the drive rollers 24 in another position of the intestine 8.

Fig. 5 illustrates a graph 30 depicting the electrical resistance R as a function of time T. At the time between 0 and T ₁ , the electrical re- sistance R has a relative constant level R3. At the time between T ₁ and T ₂ , the electrical resistance R drops to a lower relative constant level R ₁ . The duration of this time period AT is indicated. Hereafter the electrical resistance R is increased to the relative constant level R ₃ .

To avoid a false alarm, the detection unit comprises an electric circuitry that is configured to detect when the electrical resistance R between the surrounding portion and the tubular member is below a predefined level R ₂ for a time period being longer than a predefined non-zero time T'. T' and R ₂ are indicated in the graph. Since the time period AT is larger than the predefined non-zero time T', the measurement is not consid- ered as a false alarm. In one embodiment, R ₂ is 10 MΩ.

Fig. 6 illustrates a schematic view of detection device 2 according to the invention. The detection unit 2 comprises a surrounding portion that comprises a first part 4 and a second part 4'. The first part 4 and the second part 4' comprises a semi-cylindrical portion. The surrounding portion surrounds a tubular member 10 that extends centrally along the longitudinal axis of the surrounding portion. The tubular member 10 is grounded. An intestine 8 is suspended on the tubular member 10.

The first part 4 is connected to an insulating structure 32 that is sand- wiched between a protruding portion of the first part 4 and a conductive structure 34. The conductive structure 34 is grounded and attached to a non-conduction screen 36.

A predefined electrical potential U is provided at the surrounding por- tion. If a water film establishes an electrical connection between the first part 4 and the conductive structure 34 the potential difference U ₁ between the first part 4 and the conductive structure 34 will be zero. If, however, there is no water on the insulating structure 32, there will be a non-zero potential difference U ₁ .

By measuring the potential difference between the first part 4 and the conductive structure 34 it is possible to detect if the surrounding portion is electrically insulated from the conductive structure 34. The conduc- tive structure 34 may be a metal plate.

If the surrounding portion is electrically insulated from the conductive structure 34 measurement of the potential difference (or electrical cur- rent or electrical resistance) between the first part 4 and the tubular member 10 can be used to detect if there is a leakage hole in the water pressurised intestine 8 suspended on the tubular member 10.

Fig. 7 illustrates a perspective view of a detection unit according to the invention. The detection unit 2 comprises a surrounding portion com- prising a first part 4 and a second part 4' that are made of metal (e.g. stainless steel). The parts 4, 4' are movable relative to each other. The first part 4 comprises a semi-cylindrical part that is attached to a screen 36 made in a non-conducting material such as plastic. The first part 4 comprises a mounting plate that is attached to the screen 36 by means of screws.

Each of the two screens 36 surrounds a portion of a rotatably mounted clamping roller 26. The clamping rollers are arranged and configured to be brought into a configuration, in which the press against an intestine and hereby clamp the intestine in such a manner that the intestine can be pressurised with a liquid (e.g. water).

The lower screen 36 is slidably mounted on a slide rod 18 extending horizontally. In the configuration shown in Fig. 7 an intestine can enter through the surrounding portion since the first part 4 is spaced vertical- ly from the second part 4'. The first part 4, however, is mounted in such a manner that it can be vertically displaced and hereby be brought into contact with the second part 4' so that the first part 4 and the second part 4' are electrically connected and that the surrounding portion is arranged in a configuration, in which it surrounds the intestine (not shown).

Fig. 8 illustrates a side view of a tubular member 10 having a distal end that is arranged between a set of drive rollers 24 and a set of clamping rollers (as the one shown in Fig. 7). Each of the drive rollers 24 are partly surrounded by a screen. The screen of the lower driving roller 24 is slidably arranged on a slide rod 18.

Each drive roller 24 comprises a circumferential track configured to en- gage with the tubular member 10. The track is shaped to receive half of the tubular member 10 so that the non-tracked portion of the drive roll- ers 24 will bear against each other when the tracks are brought into contact with the tubular member 10. The track is provided with furrows for enhancing the grip.

Fig. 9 illustrates an intestine detector 38 according to the invention. The intestine detector 38 comprises a first end detector 40 and a second end detector 40' arranged in a non-zero distance from the first end de- tector. The intestine detector 38 comprises an intermediate detector 42 arranged and distanced between each of the end detectors 40, 40' in such a configuration that the intermediate detector 42 will be electrical- ly connected to any intestine suspended on the end detectors 40, 40' and extending between the first end detector 40 and the second end detector 40'.

Each of the end detectors 40, 40' are shaped to receive and maintain an intestine suspended on the end detector 40, 40'. The end detectors 40, 40' have the same geometric form. The end detectors 40, 40' comprise a hook-shaped portion. The intermediate detector, however, has a straight distal portion extending between the first end detector 40 and the second end detector 40'. The end detectors 40, 40' extend through a mounting box that compris- es electrical connection structures for connecting an electric circuitry configured to perform one or more electrical measurements by means of the detectors 40, 40', 42.

Fig. 10 illustrates a perspective side view of the intestine detector 38 shown in Fig. 9. It can be seen that the intestine detector 38 comprises two equally shaped receiving portions each comprising a set of detectors 40, 40' and an intermediate detector 42 arranged therebetween. Moreo- ver, it can be seen that the intestine detector 38 is electrically insulated by means of insulators 44 from the wall 46 onto which the intestine de- tector 38 is attached.

Fig. 11 illustrates an intestine detector 38 according to the invention. The intestine detector 38 basically corresponds to the one shown in Fig. 9. The intestine detector 38, however, comprises no second end detec- tor 40'. The intestine detector 38 comprises an intermediate detector 42 arranged and distanced from and extending parallel to the first end de- tectors 40 in such a configuration that the intermediate detector 42 will be electrically connected to any intestine suspended on the first end detector 40.

The first end detector 40 is shaped to receive and maintain an intestine suspended on the first end detector 40. The first end detector 40 com- prises a hook-shaped portion.

The first end detector 40 extends through a mounting box that compris- es electrical connection structures for connecting an electric circuitry configured to perform one or more electrical measurements by means of the detectors 40, 42.

Fig. 12 illustrates a perspective side view of the intestine detector 38 shown in Fig. 11. It can be seen that the intestine detector 38 compris- es a receiving portion comprising a first end detector 40 and an inter- mediate detector 42 arranged adjacent to the first detector 40. Moreo- ver, it can be seen that the intestine detector 38 is electrically insulated by means of insulators 44 from the wall 46 onto which the intestine de- tector 38 is attached.

List of reference numerals

2 Detection unit

4, 4' Part

6 Liquid

8 Intestine

10 Tubular member

12 Leakage hole

14 Electric circuitry

16 Bracket

18 Rod

20 Processing unit

22, 22' Wire

24 Roller

26 Roller

28 Perforation

30 Graph

32 Insulating structure

34 Conductive structure

36 Non-conduction screen

38 Intestine detector

40, 40' End detector

42 Intermediate detector

44 Insulator

46 Wall

R, R ₁ Resistance

R ₂ , R ₃ Resistance

T, T, AT Time

T ₁ , T ₂ Time

D Distance

V Velocity

L Length

G Electrical grounding

U, U ₁ , u ₂ Voltage