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Title:
FISH PROCESSING MACHINE WITH A BLOOD LINE CUTTER
Document Type and Number:
WIPO Patent Application WO/2017/186241
Kind Code:
A1
Abstract:
A fish processing machine for gutting fish comprising an abdomen cutting device for cutting open an abdomen of said fish from outside and providing an open abdominal cavity, and a (suction) cleaning device arranged to enter said fish to at least partly remove viscera of the fish. After this viscera removal, a blood line cutting device is arranged to enter the open abdominal cavity, solid protrusions arranged on a rotation element(a belt, chain or wheel) are used to engage with a blood line and/or a membrane of the blood line upon rotation of the rotation element. Hereby, the blood line and/or said membrane is loosened by applying a repeated pressure and/or friction caused by the solid protrusions. This provides an efficient yet gentle way of removing the blood line of the fish, which can subsequently be removed e.g. by suction.

Inventors:
KRISTENSEN, Ivan (Fallevej 48, 8800 Viborg, 8800, DK)
JØRGENSEN, Daniel Braad (Lyøvej 8, 8600 Silkeborg, 8600, DK)
Application Number:
DK2017/050119
Publication Date:
November 02, 2017
Filing Date:
April 24, 2017
Export Citation:
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Assignee:
KROMA A/S (Rævevej 22, 7800 Skive, 7800, DK)
International Classes:
A22C25/14
Domestic Patent References:
WO2015062610A12015-05-07
Foreign References:
US5735735A1998-04-07
GB1497512A1978-01-12
Other References:
None
Attorney, Agent or Firm:
PLOUGMANN VINGTOFT A/S (Rued Langgaards Vej 8, 2300 Copenhagen S, 2300, DK)
Download PDF:
Claims:
CLAIMS

1. A fish processing machine for gutting fish, said fish processing machine comprising

- an abdomen cutting device for cutting open an abdomen of said fish from

outside and providing an open abdominal cavity,

- a first cleaning device arranged to enter said fish to at least partly remove viscera of the fish, and

- a blood line cutting device arranged to enter said open abdominal cavity after the first cleaning device has at least partly removed the viscera of the fish, wherein the blood line cutting device comprises at least one solid protrusion being arranged on a rotation element, said solid protrusion being arranged to engage with a blood line and/or a membrane of the blood line upon rotation of said rotation element, and said solid protrusion being arranged to at least partly loosen said blood line and/or said membrane by applying a repeated pressure and/or friction.

2. The fish processing machine according to claim 1, wherein the blood line cutting device is arranged to enter the open abdominal cavity of a fish from above the fish, said fish being positioned on its backside. 3. The fish processing machine according to claims 1 or 2, wherein the fish processing machine comprises a second cleaning device being arranged to at least partly remove said blood line and/or said membrane from the open abdominal cavity of the fish once this has been at least partly loosened by the blood line cutting device.

4. The fish processing machine according to any of the preceding claims, wherein the blood line cutting device further comprises a mechanical arm mounted on a structure of the fish processing machine, said mechanical arm being arranged to support the rotation element, wherein the mechanical arm is arranged to be movable in at least a vertical direction relative to a fish to be processed, so as to allow the at least one protrusion on the rotation element to engage with said blood line and/or said membrane.

5. The fish processing machine according to claim 4, wherein the mechanical arm is further movable along a length of a fish to be processed, so as to allow the at least one protrusion on the rotation element to come into engagement with said blood line and/or said membrane between a first position and said second position along the length of the fish to be processed. 6. The fish processing machine according to claim 4 or 5, further comprising a control unit for controlling a movement of at least the mechanical arm, wherein the control unit is arranged to control movement of the mechanical arm relative to a fish to be processed. 7. The fish processing machine according to any of the preceding claims, wherein the rotation element comprises a chain or a belt arranged to rotate, and wherein the at least one solid protrusion is arranged on an outer edge of said chain or belt.

8. The fish processing machine according to any of the preceding claims, wherein the rotation element comprises a wheel being arranged to rotate, and wherein the at least one solid protrusion is arranged on an outer edge of said wheel.

9. The fish processing machine according to any of the preceding claims, wherein said at least one solid protrusion comprises a piece of material being relatively flat and stiff, such as a plate.

10. The fish processing machine according to any of the preceding claims, wherein a portion of said at least one solid protrusion has a generally blunt shape being arranged to engage with said blood line and/or said membrane.

11. The fish processing machine according to any of the preceding claims, wherein the rotation element is arranged to rotate around an axis being horizontal or substantially horizontal and being perpendicular or substantially perpendicular, such as 85-95 degrees, to an axis being parallel to a length of said fish, when the solid protrusion arranged on the rotation element engages with said blood line and/or said membrane.

12. The fish processing machine according to any of the preceding claims, wherein said at least one solid protrusion is arranged to engage with said blood line and/or said membrane at an interval of between 50 and 200 times/second, such as e.g. 70-100, 80-120, 90-110, 100-130 or 100-150 times/second, preferably at least 100 times/second. 13. The fish processing machine according to any of the preceding claims, wherein said at least one solid protrusion is arranged to engage with said blood line and/or said membrane and apply a repeated pressure and/or friction, said repeated pressure and/or friction being a force, such as a push, scrape, punch, pull or massaging motion, exerted on said blood line and/or said membrane repeatedly over a period of time with minor pauses in between each pressure.

14. The fish processing machine according to any of the preceding claims, wherein the blood line cutting device comprises more than one solid protrusion arranged on the rotation element, such as 2-5, 5-10, 10-20, 20-30 or 30-50 protrusions arranged on a rotation element with a distance between each of the protrusions, wherein said distance is between 10 and 100 mm.

15. A method for processing fish by means of a fish processing machine, comprising the steps of:

- cutting open an abdomen of said fish from outside using an abdomen cutting device, hereby providing an open abdominal cavity,

- at least partly removing viscera of said fish using a cleaning device,

inserting a blood line cutting device in said open abdominal cavity after the first cleaning device has at least partly removed the viscera of the fish, and - loosening a blood line and/or a membrane of the blood line by applying a

repeated pressure and/or friction using a blood line cutting device comprising at least one solid protrusion being arranged on an outer edge of a rotation element, said solid protrusion engaging with said blood line and/or said membrane.

Description:
FISH PROCESSING MACHINE WITH A BLOOD LINE CUTTER

FIELD OF THE INVENTION The present invention relates to a fish processing machine for gutting fish and a method for processing fish by means of a fish processing machine. Especially, the invention provides a fish processing machine and a method for effectively cutting a blood line of a fish, so as to allow easy removal of the blood line from the fish. BACKGROUND OF THE INVENTION

Processing machines for automatically gutting and cleaning a fish are known. Such machines may especially remove viscera of the fish through an abdominal opening by means of a suction device.

However, it is a problem with known fish processing machines that the blood line of the fish remains in the fish after removal of viscera by means of suction.

SUMMARY OF THE INVENTION

In particular, it may be seen as an object of the present invention to provide a solution to the mentioned problem of removing a blood line from a fish in an automated fish processing machine. Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention.

In a first aspect, the invention provides a fish processing machine for gutting fish, said fish processing machine comprising

- an abdomen cutting device for cutting open an abdomen of said fish from outside and providing an open abdominal cavity, the abdomen cutting device being e.g. a rotating knife,

a first cleaning device arranged to enter said fish to at least partly remove viscera of the fish, e.g. through a mouth of said fish or through said open abdominal cavity, and - a blood line cutting device arranged to enter said open abdominal cavity after the first cleaning device has at least partly removed the viscera of the fish, wherein the blood line cutting device comprises at least one solid protrusion being arranged on a rotation element, said solid protrusion being arranged to engage with a blood line and/or a membrane of the blood line upon rotation of said rotation element, and said solid protrusion being arranged to at least partly loosen said blood line and/or said membrane by applying a repeated pressure and/or friction, such as a push, scrape, punch, pull or a massaging motion being applied repeatedly in a discontinuous manner with very small gaps or pauses in between each engagement, upon rotation of the rotation element.

It is to be understood that the force applied to the blood line and membrane may comprise both a pressure and a frictional force, as the at least one solid protrusion is arranged on a rotation element and may, therefore, both e.g. push and pull the resilient blood line and membrane of the fish.

The blood line cutting device provides the advantage that it loosens the blood line of the fish with great precision, hereby avoiding other parts of the fish being damaged. The inventors of the present invention have realised that in order to effectively and efficiently remove the blood line, it is advantageous to loosen the membrane that covers the blood line. Furthermore, it has been realised that this can be achieved very effectively by applying a repeated pressure and/or friction on this membrane and, unavoidably, also on the blood line. It is to be understood that the blood line and the membrane will both be affected by an applied pressure due to the close relation between these parts in the abdomen of the fish, which is why it is not possible to differentiate between these two terms.

The inventors of the present invention have realised that the most effective way to loosen the membrane and blood line is by applying a repeated pressure and/or friction to the blood line or a membrane of the blood line, and that this can be implemented by rather simple means in an automated process when the engaging protrusion is arranged on a rotation element, e.g. on a motor driven wheel or on a motor driven belt or chain. Preferably, this is performed in a process where such repeated pressure and/or friction is performed on the major part of the

longitudinal extension of the blood line. This repeated pressure and/or friction may be a rubbing, scraping, cutting, pressing or pushing, where the membrane of the blood line is exerted to a force again and again with very short time gaps in between. Taking this approach provides the advantage that the membrane and blood line are loosened and can, thus, be removed from the fish in a gentle process, leaving no or very little damage to the other parts of the fish, compared to e.g. a scraping tool or knife. Furthermore, it has been shown by the inventors that the present invention produces really good results, completely removing the blood line and viscera in the tests performed. The blood line cutting device is installed in a fish processing machine which may perform further processing of the fish. This may further comprise means for precisely aligning and guiding the fish to be processed, such as clamping mechanisms, controllable supports and a device for receiving a fish and

transporting it through the fish processing machine.

In the following, preferred features and embodiments will be described.

In an embodiment, the blood line cutting device of the present invention may be arranged to enter the open abdominal cavity of a fish from above the fish, said fish being positioned on its backside. This provides the advantage that the blood line cutting device may be installed in existing fish processing machines, which are often designed to process fish positioned on their backsides using processing tools, which are projected from the top of the fish processing machines into the abdominal cavity of fish to be processed.

The first cleaning device may comprise suction means, a brush, a spinning wheel or a cleaning device using water to remove viscera from the fish.

The fish processing machine may further comprise a second cleaning device being arranged to at least partly remove said blood line and/or said membrane from the open abdominal cavity of the fish once this has been at least partly loosened by the blood line cutting device. Especially, the second cleaning device may comprise suction means, a brush, a spinning wheel or a cleaning device using water to remove viscera from the fish. In a preferred embodiment, the blood line cutting device may comprise a mechanical arm mounted on a structure of the fish processing machine, said mechanical arm being arranged to support the rotation element. The mechanical arm may be an elongated member or structure, which is able to project from a stationary position to an operating position within the fish processing machine, such as from a stationary position at a distance above a transport path to an operating position inside the abdominal cavity of a fish to be processed. The mechanical arm may be a structure comprising more than one elongated member being attached to one another, while still allowing vertical and/or horizontal rotation of one or more members. This provides the advantage that the rotation element supported by the mechanical arm can be moved in both a vertical and a horizontal direction by activating different parts of the mechanical arm. The complete mechanical arm may, furthermore, be able to move horizontally and/or vertically in relation to a stationary structure of the fish processing machine.

The mechanical arm may be arranged to be movable in at least a vertical direction relative to a fish to be processed, so as to allow the at least one protrusion on the rotation element to engage with said blood line and/or said membrane. The mechanical arm may further be movable along a length of a fish to be processed, so as to allow the at least one protrusion on the rotation element to come into engagement with said blood line and/or said membrane between a first position and said second position along the length of the fish to be processed. This provides the advantage that the blood line cutting device is able to loosen the blood line and the membrane very effectively, as it can be inserted just beneath the head of the fish, where the blood line and membrane are attached and follow the blood line and membrane along the length of the fish, so as to completely loosen the blood line and membrane by applying a repeated pressure or friction, such as to loosen the blood line and/or membrane along at least the major part of its extension in the length of the fish.

The fish processing machine may comprise a control unit for controlling a movement of at least the mechanical arm, wherein the control unit is arranged to control movement of the mechanical arm relative to a fish to be processed, e.g. in response to a sensor, camera or mechanical measuring device providing measurements or other characteristics of said fish. The control unit may control the movement of the mechanical arm, so as to allow the blood line cutting device to be positioned correctly relative to the autonomy of a fish to be processed and to exert the right amount of pressure on the blood line or membrane.

According to a preferred embodiment, the rotation element may comprise a chain or a belt arranged to rotate, wherein the at least one solid protrusion is arranged on an outer edge of said chain or belt, such as welded or otherwise attached to an outer edge of the chain or belt, or the at least one solid protrusion may be an integral part of the chain or belt.

According to another preferred embodiment, the rotation element may comprise a wheel being arranged to rotate, wherein the at least one solid protrusion is arranged, such as welded, on an outer edge of said wheel.

In one embodiment of the present invention, the at least one solid protrusion comprises a piece of material being relatively flat and stiff, such as a plate or plate-like element. The at least one solid protrusion may have a generally blunt shape being arranged to engage with said blood line and/or said membrane, such as ending in a flat, an obtuse or a non-sharp edge. It is to be understood that the solid protrusion may e.g. be rounded at a free end being arranged to engage with the blood line or membrane, or the protrusion may have another blunt shape at said free end, such as a tapered form not ending in a sharp point. It has been realised by the inventors of the present invention that it is advantageous to allow the protrusion to have a blunt shape, as this reduces the risk of the blood line cutting device destroying other parts of the fish than the blood line and membrane. It may be seen as counterintuitive to use a blunt or non-sharp edge in a cutting device, but it has been realised that it is advantageous to use such a shape and allow the protrusion to rub or massage against the blood line and membrane, as this gives a more gentle removal of the blood line than by more destructive means such as a knife or stationary scraper. Furthermore, as the membrane may be quite resilient, it may be advantageous to apply a repeated pressure and friction using a blunt shape, so as to break through it. In an alternative embodiment, the at least one solid protrusion may have a shape being arranged to engage with said blood line and/or said membrane, which is not blunt, such as a sharp edge or pointed element. In a preferred embodiment, the at least one solid protrusion may have a width measured in a direction parallel to a line going through a centre of rotation of the rotation element, and a height measured from the outer edge of the rotation element where the protrusion is attached to the rotation element to a free end of the protrusion, wherein said width gradually decreases along at least a part of the height of said protrusion, providing a cross-section of said protrusion being a tapered form, a triangle, a semicircle or a four-sided tapered form ending in a non-sharp point.

A shape and a size of said protrusion is preferably adapted to a shape and a size of a fish to be processed, so as to allow the protrusion to engage with the blood line and membrane without damaging other parts of a fish being processed.

Especially, the at least one solid protrusion may comprise a metallic material or a polymeric material. The at least one solid protrusion may be formed monolithically with the rotation element, or at least a part of the rotation element, however the at least one solid protrusion may be attached or fastened to the rotation element.

The blood line cutting device may further comprise a first plurality of metallic protrusions and a second plurality of polymeric protrusions, said metallic protrusions and said polymeric protrusions being arranged with a mutual distance on the rotation element in an alternating order, e.g. as separate elements attached to an outer edge of a belt or a chain.

The rotation element may be arranged to rotate around an axis being horizontal or substantially horizontal and perpendicular or substantially perpendicular, such as 85-95°, to an axis being parallel to a length of said fish, when the solid protrusion arranged on the rotation element engages with said blood line and/or said membrane. This provides the advantage that the at least one solid protrusion is able to move by rotation in a direction along the length of the blood line and engage with the blood line by pushing and/or pulling it along its own length, which has been proven by the inventors to give a very effective removal of the blood line. By 'horizontal' means parallel with the (plane) ground on which the fish processing machine is placed. The at least one solid protrusion may be arranged to engage with the blood line and/or membrane at an interval of between 50 and 200 times/second, such as e.g. 70-100, 80-120, 90-110, 100-130 or 100-150 times/second, preferably at least 100 times/second which has been found to provide good blood line loosening results.

The at least one solid protrusion may be arranged to engage with the blood line and/or the membrane and apply a repeated pressure and/or friction, said repeated pressure and/or friction being a force, such as a push, scrape, punch, pull or massaging motion, exerted on said blood line and/or said membrane repeatedly over a period of time with minor pauses in between each pressure. By a repeated pressure and/or friction is to be understood that a first engagement with the blood line or membrane is followed by a pause, followed by a second engagement, so as to subject the blood line or membrane to a pressure and/or friction discontinuously with small time gaps or pauses in between.

The repeated pressure and/or friction may be applied for a duration of more than 1 second, such as 2-5, 5-10, 7-11 or 10-15 seconds. Especially, the repeated pressure and/or friction process may be performed for this duration in a continuous motion where the rotation element rotates continuously, and where the rotation element is moved a certain distance along a length of the fish to preferably loosen the entire length of the blood line.

The blood line cutting device may comprise more than one solid protrusion arranged on the rotation element, such as 2-5, 5-10, 10-20, 20-30 or 30-50 protrusions.

The blood line cutting device may comprise a plurality of protrusions being arranged on a rotation element with a distance between each of the protrusions, wherein said distance is between 10 and 100 mm, such as e.g. 10-20, 20-30, 30- 40, 40-50 or 20-40, preferably about 25 mm. The rotation element may be driven by a motor, said motor causing the at least one protrusion on the outer edge of the rotation element to move at a speed of between 1 and 5 m/s, such as 1-2, 2-2.5, 2.5-3, 3-4 or 4-5 m/s, preferably around 2.5 m/s.

In a second aspect, the invention provides a method for processing fish by means of a fish processing machine, comprising the steps of:

- cutting open an abdomen of said fish from outside using an abdomen cutting device, hereby providing an open abdominal cavity,

- at least partly removing viscera of said fish using a cleaning device,

- inserting a blood line cutting device in said open abdominal cavity after the first cleaning device has at least partly removed the viscera of the fish, and

- loosening a blood line and/or a membrane of the blood line by applying a repeated pressure and/or friction using a blood line cutting device comprising at least one solid protrusion being arranged on an outer edge of a rotation element, said solid protrusion engaging with said blood line and/or said membrane.

In an embodiment relating to this aspect of the invention, the method may further comprise conveying a fish to be processed positioned on its backside along a transport path.

In another embodiment, the method may comprise conveying a fish with a head pointing forward in a transport direction.

The method according to this aspect of the invention may comprise the blood line cutting device being arranged to enter said fish through said open abdominal cavity from above, when the fish is positioned on its backside. According to another embodiment, the method may comprise the at least one solid protrusion being arranged to engage with said blood line and/or said membrane at an interval of between 50 and 200 times/second, such as e.g. 70- 100, 80-120, 90-110, 100-130 or 100-150 times/second, preferably at least 100 times/second. The invention according to the first and second aspects are applicable to processing of a large number of different fish of various sizes, e.g. salmon. The invention is particularly suitable for processing fish with their heads still on. It is to be understood that features and embodiments of the first and second aspect of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE FIGURES

The fish processing machine according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

FIGs. la-lc show different views of a blood line cutting device with a rotation belt. FIG. 2 shows different views of a protrusion embodiment arranged for

engagement with the blood line or membrane of the fish.

FIGs. 3a-3c show different views of a blood line cutting device with a rotation wheel.

FIG. 4 shows a side view of a fish processing machine embodiment where a fish is being processed.

FIG. 5 shows a 3D view of a fish processing machine embodiment with indication of the location of a blood line cutting device.

FIGs. 6 and 7 show photos of a salmon being processed by a blood line cutting device embodiment based on a rotation belt.

FIG. 8 shows steps of a preferred method embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. la shows a side view of a mechanical arm MA according to an embodiment of the present invention. The mechanical arm MA is arranged to support a rotation element shown as a belt BT and a motor M causing the belt to rotate. A plurality of plates PLT are arranged on an outer edge of the belt, these showing one embodiment of the at least one protrusion according to the present invention. The belt BT is rotated by use of a further belt or chain, here shown as a belt PTB, transferring mechanical power from a shaft of the motor M to a shaft of a toothed wheel TWH supporting the belt BT and causing it to rotate.

FIG. lb shows the same embodiment as Fig. la, but in a front view.

FIG. lc shows the same embodiment as Fig. la and Fig. lb in a perspective view. FIG. 2 shows different views of an embodiment of a solid protrusion being suitable for being arranged on a rotation element. The embodiment shown is a protrusion having a width W measured in a direction parallel to a line going through a centre of rotation of the rotation element, and a height H measured from the outer edge of the rotation element where the protrusion is attached to the rotation element to a free end of the protrusion, wherein said width gradually decreases along at least a part of the height of said protrusion, providing a cross-section of said protrusion being a tapered form. The free end FE of the protrusion is also shown, said end being the edge engaging with the blood line and/or the membrane.

FIG. 3a shows another embodiment of the mechanical arm MA according to the present invention. In this embodiment, the rotation element is a wheel WL being arranged to rotate, wherein the at least one solid protrusion PRT is arranged on an outer edge of said wheel. In the embodiment shown, the wheel WL is a thin, round plate with a plurality of pointed protrusions PRT on its outer edge. The wheel WL is able to rotate due to the motor M.

FIG. 3b shows the same embodiment as Fig. 3a in a front view. FIG. 3c shows the same embodiment as Fig. 3a and Fig. 3b in a perspective view.

FIG. 4 shows a schematic representation of a fish processing machine comprising a blood line cutting device according to an embodiment of the present invention, in which the fish to be processed is positioned on its backside and transported head first in a transport direction.

FIG. 5 shows a perspective view of a fish processing machine according to an embodiment of the present invention. In the embodiment shown, the blood line cutting device comprises a mechanical arm mounted on a structure of the fish processing machine, said mechanical arm being arranged to support the rotation element. The mechanical arm is able to project from a stationary position to an operating position within the fish processing machine, such as from a stationary position at a distance above a transport path to an operating position inside the abdominal cavity of a fish to be processed. FIGs. 6 and 7 are photos of a blood line cutting device according to an

embodiment of the present invention being inserted in an open abdominal cavity of a fish. In the embodiment shown, the blood line cutting device comprises a rotation belt with protrusions. The blood line cutting device is inserted just beneath the head of the fish, where the blood line and membrane are attached, after a first cleaning device (not shown in these photos) has at least partly removed the viscera of the fish. In FIG. 7, the blood line cutting device has moved to a second position along the length of the fish in its abdominal cavity. According to an embodiment, the blood line cutting device is able to move along the length of the fish, so as to completely loosen the blood line and membrane by applying a repeated pressure or friction, such as to loosen the blood line and/or membrane along at least the major part of its extension in the length of the fish. Once this operation is completed, a second cleaning device according to an embodiment of the present invention (not shown in these photos) may be inserted in the abdominal cavity to at least partly remove the blood line and/or the membrane from the open abdominal cavity of the fish after this has been at least partly loosened by the blood line cutting device.

FIG. 8 shows steps of a preferred method embodiment, comprising the steps of: First, cutting open an abdomen of said fish from outside using an abdomen cutting device, hereby providing an open abdominal cavity.

Next, at least partly removing viscera of said fish using a cleaning device.

Subsequently, loosening the blood line of the fish, by inserting a blood line cutting device in said open abdominal cavity after the first cleaning device has at least partly removed the viscera of the fish, and loosening the blood line and/or a membrane of the blood line by applying a repeated pressure and/or friction using a blood line cutting device comprising at least one solid protrusion being arranged on an outer edge of a rotation element, said solid protrusion engaging with said blood line and/or said membrane, and finally removing the loosened blood line from the abdominal cavity of the fish, e.g. by means of a suction device inserted into the abdominal cavity of the fish.

To sum up, the invention provides a fish processing machine for gutting fish comprising an abdomen cutting device for cutting open an abdomen of said fish from outside and providing an open abdominal cavity, and a (suction) cleaning device arranged to enter said fish to at least partly remove viscera of the fish. After this viscera removal, a blood line cutting device is arranged to enter the open abdominal cavity, solid protrusions arranged on a rotation element (a belt, chain or wheel) are used to engage with a blood line and/or a membrane of the blood line upon rotation of the rotation element. Hereby, the blood line and/or said membrane is loosened by applying a repeated pressure and/or friction caused by the solid protrusions. This provides an efficient yet gentle way of removing the blood line of the fish, which can subsequently be removed e.g. by suction.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.