WO2006039932A2

WO2006039932A2 - Method and machine for processing of fish

Info

Publication number: WO2006039932A2
Application number: PCT/DK2005/000665
Authority: WO
Inventors: Svend Erik Juul; Henry Nielsen; Søren Smed NIELSEN; Ivan Kristensen; Thomas Geertsen; Jimmy Nielsen
Original assignee: Kroma A/S
Priority date: 2004-10-14
Filing date: 2005-10-14
Publication date: 2006-04-20
Also published as: JP2008516587A; WO2006039932A3

Abstract

A machine as well as a method of automatic processing fish by e.g. gutting the fish and cleaning the body cavity thereof is disclosed, wherein the height of the fish between the back side and the belly side thereof together with the corresponding longitudinal position from the head of the fish, in particular the distal end or the snout of the fish, is determined, and are used to control the at least some of the cutting and cleaning processes for fish of various sizes and shapes. In a particular embodiment, the maximum height of the fish and the corresponding longitudinal distance from the head of the fish are determined.

Description

METHOD AND MACHINE FOR PROCESSING OF FISH

The present invention relates to a machine as well as a method of processing fish, i.e. of automatically preparing fish for consumption by e.g. gutting the fish and cleaning the body cavity thereof.

BACKGROUND OF THE INVENTION

Automated processing of fish is well-known in the art, but the known machines and methods normally requires that the fish are pre-sorted before they are entered into the machine, so that fish of a given size or size range only is entered into the machine, which is preset to process fish of that given size and of a given fish specie. However, it is desirable that a machine can handle fish of a broader range of sizes.

In US 4,899,422 by King, a machine is disclosed in which the length of the fish is determined and is applied to control the operation of processing mechanisms, e.g. cutting devices along the processing path, by means of a set of proportionality values for the given fish specie.

However, it has been found by the present inventors that such system does not suffice for the required precision of the processing steps, e.g. for controlling a cutting of the oesophagus, the gills and/or a longitudinal opening in the belly side of the fish, which allows for efficient gutting of the fish without unintentionally damaging the fish body or the intestines, resulting in a contamination of the fish meet, in insufficient cleaning of the fish or the rupture of the roe sack and loss of the valuable roe.

Thus, it is an object of the present invention to provide an improved machine for and a method of processing fish of different sizes. BRIEF DESCRIPTION OF THE INVENTION

It has been realised by the present inventors that the length of a fish of a given specie is not a sufficient measure to predict the proportional values of the fish with a precision so that an automated processing of the fish may be performed satisfactory. However, the height of the fish between the back side and the belly side thereof together with the corresponding longitudinal position from the head of the fish, in particular the distal end or the snout of the fish, provides a much more useful input for predicting the proportional values. In a most preferred embodiment, the determination of the maximum height of the fish and the corresponding longitudinal distance from the head of the fish, may be used as a sufficient measure to predict the proportional values of the fish with a precision so that an automated processing of the fish may be performed satisfactorily.

The present invention provides a machine that is capable of handling fish within a wide range of sizes successfully, such as within a range of 1 to 5 kg or up to 8 kg.

Thus, the present invention relates to a machine for processing of fish, comprising cutting means for performing a cut in the belly side of the fish, while leaving the head and the body of the fish mutually connected, height sensor means arranged to produce a measure indicative of a distance between the back side and the belly side of the fish in a direction substantially perpendicular to the longitudinal direction of the fish and providing an output accordingly to a control means of the machine, length sensor means arranged to produce a measure indicative of the distance in the longitudinal direction from a fixed position of the head of the fish to a given position in the longitudinal direction and providing an output accordingly to said control means, the control means being arranged to produce control signals for each individual fish in response to the output from said sensor means, wherein positioning means of the cutting means controls the longitudinal position of the cutting means with respect to a fish in response to said control signals during operation of the cutting means.

The present invention is directed to the processing of whole fish, i.e. where the fish is not decapitated, as this is preferred for many purposes of use of the fish. However, the fish may of cause be decapitated after the processing according to the present invention.

The height sensor means may be a contactless device, such as a bank of photo cells, a visual scanner or an electronic camera with suitable processing means, but it is preferred that the height sensor means comprises a mechanical sensor, which is more tolerant to fouling during the operation of the machine than contactless devices based on visual contact.

The length sensor means for producing a measure indicative of the distance in the longitudinal direction from a fixed position of the head of the fish, such as the distal end of the head, the snout, to a given position in the longitudinal direction and producing an output accordingly to said control means, and said control signals are in that case produced in response to said output as well as the output from the height sensor means.

The positioning means of the cutting means may furthermore control the cutting depth of the cutting means in a direction substantially perpendicular to the longitudinal direction of the fish in response to said control signals during operation of the cutting means. This is advantageous with respect to cutting of the oesophagus as well as the gills of the fish between the head and the body thereof to ensure a proper severing thereof without the risk of decapitating the fish or severing the backbone, so that the head may be torn off the body at a later stage, as well as with respect to the longitudinal cutting of the belly side preparing the fish for gutting without damaging the organs in the body cavity of the fish, i.e. the stomach, the liver, the intestines, the swim bladder, and in particular the roe sack.

In a preferred embodiment, a measure of the maximum (Y) of said distance between the back side and the belly side of the fish is determined, the distance (X) in the longitudinal direction from a fixed position of the head of the fish to the position of said maximum distance (Y) is determined from the output of said length sensor means, and wherein and said control signals are produced in response to said maximum (Y) and said distance (X). From this set of values, (X, Y), is has turned out that the overall shape of the fish can be estimated, e.g. by selecting one from a predetermined set of standard sizes and shapes.

The cutting means may preferably include means arranged for opening the belly side of the fish with a longitudinal cut, such as a circular cutter and a spear cooperating with the circular knife. The precise longitudinal and vertical position for the cutting means to enter the belly side of the fish, such as through a slit made for severing the gills and optionally the oesophagus of the fish, and the vertical level of the cutting means as it passes along the belly side of the fish for cutting the opening slit may both be controlled from said determined values of height and longitudinal distance so that damaging of the intestines and in particular the roe sack is prevented.

Additionally or alternatively, the cutting means may be controlled in response to the determined values of height and longitudinal distance and may include means arranged for severing the oesophagus of the fish and optionally for severing the gills of the fish for the purpose of facilitating the gutting of the fish, i.e. the process of removing organs from the belly cavity of the fish. In particularly the oesophagus is elastic and difficult to break by pulling and the organs, such as the intestines may be removed by hand or by suction when the oesophagus is severed, whereas the gills may be severed in order to facilitate the removing of the roe sack without being ruptured. The tool that preferably is employed for severing the oesophagus and the gills is a pair of clipper blades with a width of e.g. 25 millimetres to 60 millimetres, such as 40 to 50 millimetres. The toothed clipper blades are mutually displaced in an oscillating movement to effect the cutting by means of a drive organ.

Alternatively to the use of the detected height and longitudinal distance for controlling the position of the cutting means for cutting the gills, the machine may comprise detection means for detecting the position of the collar bone, i.e. the clavicle, of the fish, such as a mechanical detector, e.g. pins that are entered into the gill slits, i.e. the branchial clefts, of the fish and engages the collar bones and slide along these for guiding the guiding gill cutting means to severe the gills of the fish. Alternatively to a mechanical solution, the position of the collar bones may be detected precisely by means of an infrared light source on one side of the fish and an infrared detector on the opposite side. Other possibilities are ultrasound detectors, inductive detectors and a vision system. Such arrangement may furthermore comprise means arranged for severing the oesophagus of the fish subsequently to the severing of the gills through the opening in the fish made by the gill cutting means. In particular, said means for severing the oesophagus of the fish may in a preferred embodiment comprise engagement means for engaging the collar bone of the fish through the opening in the fish made by the gill cutting means, the engagement means being arranged to control the longitudinal position of the means for severing the oesophagus with respect to the fish.

In a further embodiment, the cutting of the oesophagus and/or the gills may be controlled by the output of a non-contact sensor as and infrared sensor etc. as discussed above and, in case the output of the sensor is deemed to be unreliable by the control means of the machine, the detected height and longitudinal distance may be applied to control the positioning and operation of the cutting means for cutting of the oesophagus and/or the gills. The machine may furthermore comprise a cleaning device for cleaning of the body cavity of the gutted fish, in particularly for removing the so-called blood sack (actually the kidney) along the backbone of the fish, the cleaning device comprising at least one rotating disk-shaped brush, drive means for driving the rotation of said brush and positioning means to control the position of the brush with respect to the fish in response to said control signal during operation of the cleaning device. Such brushes are e.g. shown in US 4,882,811 and in WO 90/03115, but the improved position control of the brushes enabled with the present invention improve the efficiency of the brushes radically. It is particularly advantageous in case the cleaning device comprises two disk-shaped brushes with drive means for rotating each brush in the disk-plane thereof, the disk-planes of the two brushes being oblique with respect the plane of symmetry of the fish with opposing angles, i.e. the brushes are arranged with their disk-planes substantially in the symmetry plane of the fish but tilted somewhat each to one side with respect to the longitudinal direction of the fish to form the oblique arrangement. The disk-planes of the two brushes may preferably each form an angle in the range of 5° to 30°, more preferred in the range of 8° to 20°, with the plane of symmetry of the fish. A third disk-shaped brush arranged with it's disk-plane in the symmetry plane of the fish may furthermore be provided. The machine should furthermore comprise conveyor means for effecting a relative movement of said brushes along the longitudinal direction of the gutted fish.

The machine according to the invention as discussed above may furthermore comprise a conveyor for conveying fish in a transport direction, drive means for driving the conveyor, and fish engagement means arranged to engage the heads of fish loaded onto the conveyor at a loading station of the machine.

The present invention also relates to a method of processing fish, the method comprising the steps of situating the fish on a conveyor with the belly side of the fish facing upwards, determining a height of the belly side of the fish, i.e. a vertical position of the middle of the belly side of the fish, determining a distance in the longitudinal direction from a fixed position of the head of the fish to the longitudinal position of the fish, where said height is determined, making a cut in the belly side of the fish by means of a first cutting means while leaving the head and the body of the fish being mutually connected, the longitudinal position of the first cutting means with respect to the fish being controlled in response to said determined height and distance.

The cutting depth of the first cutting means downwards in a direction substantially perpendicular to the longitudinal direction of the fish may also be controlled in response to said determined height.

In particular, the maximum (Y) of said height is determined and the distance (X) in the longitudinal direction from a fixed position of the head of the fish to the position of said maximum (Y) height are determined, and the longitudinal positioning and/or cutting depth of the cutting tool is controlled in response to said maximum (Y) and distance (X).

The method may in particular include the step of making a longitudinal cut by means of the cutting means for opening the belly side of the fish, wherein the position of the second cutting means is controlled in response to the determined height and distance.

Also, the method comprises the step of severing the oesophagus of the fish, the positioning of the means for severing the oesophagus being made in response to said determined height and distance. The step may furthermore involve the severing of the gills of the fish. Alternatively, the method may comprise the steps of detecting the position of the collar bone of the fish and severe the gills of the fish according to the detected position of the collar bone. It may further comprise the step of severing the oesophagus of the fish subsequently to the severing of the gills through the opening in the fish made by the gill cutting means. In a preferred embodiment, the step of the method involves engaging engagement means with the collar bone of the fish through the opening in the fish made by the gill cutting means, and control of the longitudinal position of the means for severing the oesophagus with respect to the fish by means of the engagement means.

Also, the step of gutting the opened fish, which may be performed manually or automatically by means of suction, and the subsequent step of cleaning the body cavity of the fish by means of at least one rotating disk-shaped brush, wherein the position of the brush is controlled in response to the same measures as the first cutting means, may be included in the method. The cleaning step may in particular include the use of two rotating disk-shaped brushes, the disk-planes of which being oblique with respect the plane of symmetry of the fish with opposing angles. The disk-planes of the two brushes may in an advantageous embodiment each form an angle in the range of 5° to 30°, preferably in the range of 8° to 20°, with the plane of symmetry of the fish and the longitudinal direction of the fish.

The present invention relates in another aspect to a device for cleaning of the body cavity of gutted fish comprising two disk-shaped brushes with drive means for rotating each brush in the disk-plane thereof and conveyor means for effecting a relative movement of said brushes along the longitudinal direction of the gutted fish, wherein the disk-planes of the two brushes are oblique with respect the plane of symmetry of the fish with opposing angles. In particular, the disk-planes of the two brushes may each form an angle with respect to the longitudinal direction of the fish in the range of 5° to 30°, preferably in the range of 8° to 20°, with the plane of symmetry of the fish. A third disk-shaped brush arranged with it's disk-plane in the symmetry plane of the fish may furthermore be provided.

Although the machine according to the present invention may handle fish of varying sizes within a wide range, it may be advantageous that is machine or other machines for the processing of fish is arranged subsequent to a fish sorting apparatus which according to another aspect of the present invention may comprise a first conveyor unit, such as a conveyor belt, for retrieving dead or unconscious fish from a basin and to a separation arrangement. Here, the fish are arranged on line and turned by means, that are known per se in the art, so that the fish all have the head directed in a given direction and the belly side in another given direction. All the fish are scanned with an optical scanner and a measure for the volume of each of the fish is determined, and the fish are separated for different processing machines according to their volume, e.g. to two or three different processing machines. Now, the fish may be loaded automatically into the processing machines because their orientation and size range is well defined. The volume scanning may be performed before or after the uniform orientation of the fish has been performed, but it is preferred to volume scan the fish after that step.

BRIEF DESCRIPTION OF THE FIGURES

An embodiment of the present invention is shown in the enclosed drawings, of which Fig. 1 is a side view of the machine, Fig. 2 is a perspective view of the machine, Fig. 3 is a detailed view in perspective of a height sensor of the machine,

Fig. 4 is a detailed view in perspective of a first cutting means of the machine, Fig. 5 is a second detailed view in perspective of the first cutting means of Fig. 4, Fig. 6 is a detailed view in perspective of a second cutting means of the machine, Fig. 7 is a detailed view in perspective of a disk-shaped brush of the machine, Fig. 8 is a perspective view of an alternative embodiment of gill cutting means and oesophagus cutting means arranged on the machine, Fig. 9 is a detailed side view of the gill cutting means of Fig. 8, and Fig. 10 is a detailed side view of the oesophagus cutting means of Fig. 8.

The machine shown in the drawings is an example of an embodiment of the present invention and is not to be regarded as limiting of the scope of the present invention as defined in the appended claims.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

An embodiment of the present invention¹ is disclosed below with reference to the enclosed drawings.

The machine 1 as shown in Figs. 1 and 2 comprises a conveyor chain 2 with plates 3 for supporting the fish and hooks 4 for engaging the heads thereof. The conveyor chain 2 is driven in a constant speed of advance by means of an electric motor (not shown). A feeding unit 5 is arranged to receive the fish with the head in front and the belly side upwards and feed them to the conveyor chain 2. A height sensor 6 is arranged right after the feeding unit 5 in the direction of the movement of the conveyor chain 2, followed by a first cutting means 7 for severing the oesophagus and the gills of the fish. A second cutting means 8 for cutting a longitudinal opening in the belly side of the fish is arranged thereafter. Next is room 9 for a human operator for removing the organs inside the body cavity of the fish, which operation optionally may be replaced by an automated operation. A cleaning device 10 is arranged for cleaning the body cavity of the fish after the removal of the inner organs, and the fish are discharged at a discharge station 11.

The conveyor chain 2 comprises a plurality of sections starting with a hook 4 for engaging a head part of a fish, followed by three plates 3 for supporting the back side of the fish. An encoder (not shown) measures the advance of the conveyor chain 2 in steps of 2 millimetres and provides an output to the control means (not shown), and is used for the timing of the processing means 6, 7, 8, 10 as well as for controlling the feeding of the fish from the feeding unit 5.

The feeding unit 5 has two vertical conveyor belts between which the fish is held and advanced until its snout touches a contact, where after the belts are stopped until the encoder of the conveyor chain 2 reports that a hook 4 is in correct position for the feeding of a fish. The conveyor belts are activated to feed the fish and the hook 4 is activated to engage and hold the head of the fish in correct position. The fish is now forwarded with the conveyor chain 2 past the height sensor 6, which has a wheel 12 arranged on an arm 13 pivotally supported by a joint 14. The wheel 12 is biased downward by gravity and optionally by a spring to be in contact with the longitudinal middle of the belly side of the fish. An encoder 15 determines the angular position of the arm 13 and provides an output accordingly to the control means (not shown), which determine the maximum angular position and uses it as a measure of the maximum (Y) height of the fish. This value (Y) is used by the control means together with the corresponding longitudinal position (X) obtained from the encoder of the conveyor chain 2 to select a correct outline of the shape of the fish from 16 predefined outlines, and the selected outline is used for control of the following processing means 7, 8, 10.

The first cutting means 7 shown in Figs. 4 and 5 comprises a set of clipper blades 16 that are arranged transversal to the transport direction of the fish. A pneumatic cylinder 17 displaces the clipper blades 16 in a slanted vertical direction to effect the cutting and is controlled to obtain the correct cutting depth determined by the control means from the selected outline by displacing a rod 18 on which the clipper blades 16 are arranged. The clipper blades 16 follows the movement of the conveyor chain 2 by means of an engagement part 19 which is moved up and downwards by means of a pneumatic cylinder 20. The engagement part 19 engages the hook 4 so that the slide 21 on which the engagement part 19 and the clipper blades 16 are arranged follows the conveyor chain 2 while the clipper blades 16 are operating on the fish. The slide 21 moves on a set of guides 22 and after the cutting, the engagement part 19 disengages the hook 4 and a pneumatic cylinder 23 returns the slide 21 to its starting position to the right in Fig. 4. The longitudinal distance between the engagement part 19 and the clipper blades 16 and thereby the distance between the snout of the fish and the cut severing the oesophagus and the gills of the fish is adjusted by means of a pneumatic cylinder 24 controlled by the control means in accordance with the selected outline.

The second cutting means 8 shown in Fig. 6 comprises a spear 25 with a pointed end

26 that is inserted into the cut made by the first cutting means 7. A circular knife (not shown) is arranged above the spear 25 so that a part of the knife extends into the slid

27 provided in the spear 25 and is rotated by means of a drive means (not shown). The vertical level of the spear 25 is adjusted by means of a motor 28 with a gear wheel (not shown) engaging a toothed rack 29. The motor 28 and thereby said vertical level is controlled by the control means according to the selected outline when the pointed end 26 is engaging the existing cut and when the second cutting means 8 moves relatively along the belly side of the fish due to the movement of the conveyor chain 2, until the maximum height (X) of the belly side is reached, where after the vertical level is kept constant until the pointed end 26 exits from the fish via the vent (anus) thereof.

The cleaning device 10 comprises two disk-shaped brushes 30 as shown in Fig. 7. The brush 30 is mounted on an arm 31 that is pivotally suspended by a pivot joint 32. The disk 30 is driven in rotation about its axis of symmetry by means of an electrical motor 33. A pneumatic cylinder 34 adjusts the vertical level of the brush 30 so that it follows the back bone of the fish closely in order to remove the blood sack. The pneumatic cylinder 34 is controlled by the control means in accordance with the selected outline. The two brushes form an angle of 14° each to one side of the vertical plane of symmetry and the longitudinal direction of the fish to improve the cleaning of the body cavity.

An alternative embodiment of the machine 1 having separate gill cutting means 35 and oesophagus cutting means 36 is shown in Fig. 8, the fish moving from right to left, with the two cutting means 35, 36 arranged on the machine 1. The positioning and operation of these cutting means 35, 36 is in a primary mode of operation not controlled by means of the selected outline. Instead, collar bone detection means (not shown) are applied to detect a precise position of the collar bone, e.g. by a contact detection, where guiding pins are inserted into the gill slits of the fish, are engaged by the collar bones due to the movement of the fish and the pins are dragged along with the movement of the fish, causing the gill cutting means 35 to perform a cut from the belly side of the fish and along the front side or head side of the collar bones. In a particular embodiment, the positioning of the pins where they are inserted is controlled from a measurement of the height of the fish at a distance of 80- 120 mm from the snout of the fish. Alternatively, a non-contact collar bone detection means may be employed, such as an infrared detection means, a inductive detector or a vision system.

The gill cutting means 35 shown in detail on Fig. 9 has a rotating knife 37 arranged on an arm 38 having pneumatic cylinders 39 for changing the position and angle of the rotating knife 37. The abutment 40 engages the front end of the hook 4 by which the head of the fish is engaged and the cutting means 35 are transported along with the fish during the performance of the cut severing the gills of the fish.

The oesophagus cutting means 36 as shown in details on Fig. 10 has a set of clipper blades 16 as described previously with reference to the first cutting means 7. An abutment 41 engages the front end of the hook 4 carrying the fish and the first pneumatic cylinder 42 moves the clipper blades 16 and the collar bone hook 43 downwards, so that they enters the^* fish through the cut made by the gill cutting means 35. The collar bone hook 43 engages the collar bones of the fish on the front side i.e. head side of the bones, and the abutment 41 is lifted and disengages with the hook 4, so that the longitudinal movement of the oesophagus cutting means 36 along with the fish depends on the engagement between the collar bone hook 43 and the collar bones of the fish. A second cylinder 44 moves the clipper blades 16 further downwards to severe the oesophagus of the fish, where after the arrangement 36 is lifted for letting the fish move on and be ready to act on the subsequent fish.

The arrangement of the separate gill cutting means 35 and oesophagus cutting means 36 as shown in Figs. 8-10 may be employed separately without the other cutting means etc. of the machine and without the detection of the height and longitudinal distance as discussed above. However, when applied together, the two parts supplements each other to form a machine for complete automated opening and cleaning of the fish.

In a second mode, the control means of the machine 1 is arranged to distinguish whether of not the detection of the collar bone from a non-contact detection means is sufficiently reliable. If not, the operation of the gill cutting means 35 and the oesophagus cutting means may be controlled from the determined maximum height Y and the corresponding longitudinal distance X.

Claims

1. Machine for processing of fish, comprising cutting means for performing a cut in the belly side of the fish, while leaving the head and the body of the fish mutually connected, height sensor means arranged to produce a measure indicative of a distance between the back side and the belly side of the fish in a direction substantially perpendicular to the longitudinal direction of the fish and providing an output accordingly to a control means of the machine, length sensor means arranged to produce a measure indicative of the distance in the longitudinal direction from a fixed position of the head of the fish to a given position in the longitudinal direction and providing an output accordingly to said control means, the control means being arranged to produce control signals for each individual fish in response to the output from said sensor means, wherein positioning means of the cutting means controls the longitudinal position of the cutting means with respect to a fish in response to said control signals during operation of the cutting means.

2. Machine according to claim 1, wherein the positioning means of the cutting means furthermore control the cutting depth of the cutting means in a direction substantially perpendicular to the longitudinal direction of the fish in response to said control signals during operation of the cutting means.

3. Machine according to claim 1 or 2, wherein a measure of the maximum (Y) of said distance between the back side and the belly side of the fish is determined, the distance (X) in the longitudinal direction from a fixed position of the head of the fish to the position of said maximum distance (Y) is determined from the output of said length sensor means, and wherein said control signals are produced in response to said maximum (Y) and said distance (X).

4. Machine according to any of the preceding claims, wherein the cutting means includes means arranged for opening the belly side of the fish with a longitudinal cut.

5. Machine according to any of the preceding claims, wherein the cutting means includes means arranged for severing the oesophagus of the fish.

6. Machine according to claim 5, wherein said means furthermore is arranged for severing the gills of the fish.

7. Machine according to any of claims 1-4, comprising detection means for detecting the position of the collar bone of the fish and guiding gill cutting means to severe the gills of the fish according to the detected position of the collar bone, [clavicle] [infrared detection or mechanical detection through the gills of the fish]

8. Machine according to claim 7, comprising means arranged for severing the oesophagus of the fish subsequently to the severing of the gills through the opening in the fish made by the gill cutting means.

9. Machine according to claim 8, wherein said means for severing the oesophagus of the fish comprises engagement means for engaging the collar bone of the fish through the opening in the fish made by the gill cutting means, the engagement means being arranged to control the' longitudinal position of the means for severing the oesophagus with respect to the fish.

10. Machine according to any of the preceding claims, further comprising a cleaning device for cleaning of the body cavity of the gutted fish, comprising at least one rotating disk-shaped brush, drive means for driving the rotation of said brush and positioning means to control the position of the brush with respect to the fish in response to said control signal during operation of the cleaning device.

11. Machine according to claim 10, wherein said cleaning device comprises two disk-shaped brushes with drive means for rotating each brush in the disk-plane thereof, the disk-planes of the two brushes being oblique with respect the plane of symmetry of the fish with opposing angles, the machine comprising conveyor means for effecting a relative movement of said brushes along the longitudinal direction of the gutted fish.

12. Machine according to claim 11, wherein the disk-planes of the two brushes each form an angle in the range of 5° to 30°, preferably in the range of 8° to 20°, with the plane of symmetry of the fish.

13. Machine according to any of the preceding claims, comprising a conveyor for conveying fish in a transport direction, drive means for driving the conveyor, and fish engagement means arranged to engage the heads of fish loaded onto the conveyor at a loading station of the machine.

14. Method of processing fish, comprising the steps of situating the fish on a conveyor with the belly side of the fish facing upwards, determining a height of the belly side of the fish, determining a distance in the longitudinal direction from a fixed position of the head of the fish to the longitudinal position of the fish, where said height is determined, making a cut in the belly side of the fish by means of a first cutting means while leaving the head and the body of the fish being mutually connected, the longitudinal position of the first cutting means with respect to the fish being controlled in response to said determined height and distance.

15. Method according to claim 14, wherein the cutting depth of the first cutting means downwards in a direction substantially perpendicular to the longitudinal direction of the fish is controlled in response to said determined height.

16. Method according to claim 14 or 15, wherein the maximum (Y) of said height and the distance (X) in the longitudinal direction from a fixed position of the head of the fish to the position of said maximum (Y) height are determined, and the longitudinal positioning and/or cutting depth of the cutting tool is controlled in response to said maximum (Y) and distance (X).

17. Method according to any of claims 14 to 16, wherein the cutting means performs a longitudinal cut for opening the belly side of the fish, wherein the position of the cutting means is controlled in response to said determined height and distance.

18. Method according to any of claims 14 to 17, comprising the step of severing the oesophagus of the fish, the positioning of the means for severing the oesophagus being made in response to said determined height and distance.

19. Method according to claim 18, wherein the step furthermore involves the severing of the gills of the fish.

20. Method according to any of claims 14-17, comprising the steps of detecting the position of the collar bone of the fish and severe the gills of the fish according to the detected position of the collar bone: [clavicle] [infrared detection or mechanical detection through the gills of the fish]

21. Method according to claim 20, further comprising the step of severing the oesophagus of the fish subsequently to the severing of the gills through the opening in the fish made by the gill cutting means.

22. Method according to claim 21, wherein the step involves engaging engagement means with the collar bone of the fish through the opening in the fish made by the gill cutting means, and control of the longitudinal position of the means for severing the oesophagus with respect to the fish by means of the engagement means.

23. Method according to any of claims 14-22, further comprising the step of gutting the opened fish and the subsequent step of cleaning the body cavity of the fish by means of at least one rotating disk-shaped brush, wherein the position of the brush is controlled in response to the same measures as the first cutting means.

24. Method according to claim 23, wherein said cleaning step includes the use of two rotating disk-shaped brushes, the disk-planes of which being oblique with respect the plane of symmetry of the fish with opposing angles.

25. Method according to claim 24, wherein the disk-planes of the two brushes each form an angle in the range of 5° to 30°, preferably in the range of 8° to 20°, with the plane of symmetry of the fish.

26. Device for cleaning of the body cavity of gutted fish comprising two disk-shaped brushes with drive means for rotating each brush in the disk-plane thereof and conveyor means for effecting a relative movement of said brushes along the longitudinal direction of the gutted fish, wherein the disk-planes of the two brushes are oblique with respect the plane of symmetry of the fish with opposing angles.

27. Device according to claim 26, wherein the disk-planes of the two brushes each form an angle in the range of 5° to 30°, preferably in the range of 8° to 20°, with the plane of symmetry of the fish.