GB2391446A

GB2391446A - Method and device for slaughtering and exsanguination of fish

Info

Publication number: GB2391446A
Application number: GB0317915A
Authority: GB
Inventors: Klaus E Hoseth; Jarle Nedal; Kare Hoseth; Clifford Stanley Gardener
Original assignee: STRANDA MOTORVERKSTED AS
Current assignee: STRANDA MOTORVERKSTED AS
Priority date: 2002-08-02
Filing date: 2003-07-31
Publication date: 2004-02-11
Also published as: NO20023669D0; NO328289B1; GB0317915D0

Abstract

A device and a method for slaughtering and exsanguination of fish where the fish is given a blow to the brain region of the fish by a blow unit 15 to slaughter or stun the fish, and where the stunned or slaughtered fish is subsequently bled with the aid of an exsanguination appliance 16. A sensing appliance 14, determines the position of the brain region of the fish in relation to the head of the fish, and also in relation to the longitudinal direction of the device so that the blow given to the fish can be aimed directly and accurately towards the brain region of the fish.

Description

2391 446

Method and device for slaughtering and exsanguination of fish. 5 The present invention relates to a method and a device for slaughtering and exsanguination of fish, where a blow unit is used to inflict a blow to the brain region of the fish to kill or stun the fish, and where the stunned or slaughtered fish is thereafter drained of blood with the 10 help of an exsanguination appliance.

There is a continuous search for new apparatus and improved methods to slaughter fish. The fish farming industry is growing rapidly and it is therefore desirable 15 to develop automated methods for slaughtering. At the same time, one wants to avoid stressing the fish at the moment of slaughter as this deteriorates the quality of the fish meat. Furthermore, it is also very important that the outside of the fish is not damaged unnecessarily as fish 20 is often marketed and sold on the basis of its appearance.

There are a series of patents and patent applications that describe different methods and apparatus which can be used in a two-step slaughtering process where the fish is first 25 given a blow to the head to destroy or damage the brain.

This blow slaughters or stuns the fish. Thereafter, one or more blood vessels in the fish are cut or divided to provide a complete drainage of the blood (exsanguination).

30 The development of the present invention is also based on these two processing steps, with technical solutions provided that are not previously known, and the apparatus and the methods that are provided are clear improvements with respect to what is already known in this field.

A method and apparatus for slaughtering and exsanguination are known from EP 0 917 823. The central concept is that the fish is moved in a channel towards a certain position as the fish glides towards a stop wall. When the fish 5 meets the stop wall a signal is produced which initiates holding devices to hold the fish still in a given position. The fish is held in this position while it is slaughtered or stunned with a blow apparatus, and thereafter exsanguinated with the help of a pointed tool 10 that is pressed into the heart and/or brain. However, the solution that is described has a series of drawbacks.

The fish must be very still when it is fed into the apparatus, because the movements of the live fish result 15 in it not being kept sufficiently still to obtain an accurate direction of the blow or cutting. Live salmon and trout are not still enough for the result to be satisfactory. 20 The fish is held in position by an appliance that pushes against the snout section of the fish. The blow and cut are directed towards the fish at a given distance from this holding appliance. This is not sufficient for use with salmon. Salmon can have very different head shapes.

25 Some individuals can have short blunt heads while others have extended pointed heads. The shape depends on the degree of the spawning maturity, among other things. The position of the brain varies with the length of the head, in addition to the weight of the fish. Therefore, the 30 appliance will not hit those organs one wishes to hit' with sufficient accuracy.

The exsanguination tool is not positioned in relation to any of the natural openings of the head. The head will 35 therefore get a cut that is showing on the outside. This can depreciate the sale price of the fish.

l A natural drop is used to move the fish towards the holding appliance. In a processing line for slaughtering of fish it is important not to use too much of a drop in 5 the individual processing steps as this fall is used to transport the fish through the line. When the mentioned apparatus is used, one must put in an elevating conveyor behind the appliance to recover the fall height which is used through the apparatus.

A method and a machine for exsanguination of fish is known from NO 155 751, where the fish is pulled through the machine with the help of a pulling appliance which engages the lower, forward jaw section of the fish with the aid of 15 a hook. As mentioned above, in the slaughtering of farmed fish, much focus is put on the slaughtering taking place without inflicting unnecessary stress and pain to the fish. It can be said that the fish suffers pain as it is pulled onto the hook of the pulling appliance when fully 20 alive. The same can be said in connection with the exsanguination, where one cuts into the fish. Therefore this must be anaesthetised before it goes into the installation. Such an anaesthetisation installation is costly if one shall avoid stress during the 25 anaesthetisation.

An installation for harvesting of fish is known from NO 976 123, comprising of a room into which the fish is brought. In this room, the presence of fish and the size 30 of the fish are detected with mechanical sensors.

Thereafter, the brain of the fish is damaged with a blow appliance and thereafter another blow appliance damages one or more blood vessels in the fish. The mechanical appliances that are used to measure the size of the fish 35 are not sufficiently accurate to determine the position of the brain in relation to the blow appliance. Attempts have

been made to solve this problem by the blow tool having a long extension in the longitudinal direction. But this leads to unnecessary damage to the head. Furthermore, the apparatus is very complicated, with many components, and 5 the fish must be arranged, one by one, in the 'room" before it can be subjected to the desired treatment. The fish is further transported through the machine with the help of a drop, in that flaps are opened and closed. The loss in height of fall must be recovered sooner or later 10 with the help of an elevator conveyor.

Installations to slaughter or stun fish with the help of a blow appliance are also known from US 5,376,043 and US 4,127,919.

As pointed out, all these known solutions have clear shortcomings in connection with slaughtering and exsanguination of fish. Firstly, the blow given to the fish must be accurate, i.e. it must be aimed directly 20 towards the brain area and cannot be a more or less arbitrary blow to the head. The only solution that positions the blow appliance according to where one thinks the brain is located is NO 976 123 where one measures mechanically the size of the fish As mentioned above, 25 this will not be sufficient as the shape of the head, and thereby the location of the brain in relation to the head, will vary. This is particularly the case for salmon where some individuals have blunt heads while other individuals have extended pointed heads.

However, in the present invention one has taken this into consideration as one performs a calculation of the position of the brain with respect to the fish snout, and thereby in relation to the longitudinal direction of the 35 conveyor belt, so that the blow unit and exsanguination device can be positioned correctly.

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A further disadvantage with the solution described in NO 976 123 is that the fish must be taken into a separate room. This leads to a more complex solution and makes an 5 automation of the slaughtering process more difficult, as one is looking for a continuous and unbroken forward feeding of the fish all the time.

Thus, the present invention provides a device and a method 10 that are a substantial improvement in relation to known solutions. The device according to the invention is characterized in that it comprises; À a number of conveyor belts for forward feeding of the fish in the longitudinal direction of the device.

- a sensing appliance which determines the shape of the 20 fish's head and or the length of the head of the fish, - a control unit which, based on information from the sensing appliance, calculates the position of the brain region in the head of the fish, and which, based on the 25 information about the location of the brain in the head and about the position of the fish in the longitudinal direction of the device, where the control unit controls the blow unit to direct an accurate blow towards the brain region of the fish, and where the control unit 30 guides the exsanguination unit to penetrate a blood vessel or cut one or more of the fish's gill arches.

The method according to the invention is characterized in that the fish is moved forward in a device and that the 35 fish passes a sensing appliance, in an area in the longitudinal direction of the device, where the position

of the brain of the fish in relation to the longitudinal direction of the device is determined so that the blow unit of the device is controlled to give a blow to the brain region of the fish, and where the exsanguination 5 appliance of the device is guided to bring about a penetrating of a blood vessel or cutting of the fish's gill arches.

The invention will now be described in more detail, with 10 reference to the enclosed figures, in which: Fig. 1 shows a longitudinal section of a device according to the invention for forward feeding of the fish to be slaughtered and exsanguinated.

Fig. 2 shows a cross-section of the device according to fig. 1.

A presently preferred embodiment of the device according 20 to the invention will be explained with reference to figs. 1 and 2. The fish that is to be slaughtered is fed through the device 10, with the help of two facing conveyor belts 11. In connection to each of these conveyor belts 11, a number of pressure bodies 12, which exert a pressure by 25 way of the conveyor belts 11 to the sides of the fish, are arranged. The pressure bodies are preferably synchronized so that the fish is placed sideways centrally between the conveyor belts 11. The conveyor belts 11 are arranged in pairs and the fish is kept in a vertical position with a 30 gliding-bed 13 on the under side. In this way, a continuous forward feeding of the fish in the longitudinal direction of the conveyor belt is ensured.

As mentioned above, the blow appliance IS shall give the 35 fish a blow to its brain region, and it is therefore essential that one can determine the position of the

brain. This can be carried out based on different principles, as explained in more detail below, but one of the methods is based on a determination of the shape of the head. Thus, the device comprises a sensing appliance 5 14 which determines the shape of the head. Based on the determined shape, the position of the brain in relation to the longitudinal direction of the conveyor belt 11 is fixed. Furthermore, the device is fitted with a blow unit 15 which directs a blow towards the brain region in the 10 head of the fish to slaughter it or stun it.

Thereafter, the stunned or slaughtered fish passes an exsanguination device 16. In this device one or more blood vessels are penetrated or cut. Alternatively, the 15 exsanguination device 16 is pressed in behind the gill arches of the fish and cuts through the gill arches with a fixed movement trajectory, and subsequently pulls out again. Thereafter the fish continues out of the machine for further processing.

To calculate the position of the brain in the head of the fish, one can determine the shape of the head of the fish, or the length of the head. This gives a much more accurate estimation of the position of the brain than the method 25 which is used in present day technology, i.e. either in relation to the snout alone, or as a parameter related to the total size of the fish.

Determining the shape of the head can be carried out by 30 measuring the height of the head at one or more distances from the snout, or alternatively, in combination with measuring the breadth of the head, at one or more distances from the snout. These measurements can be carried out as the fish passes by at a fixed or variable 35 speed.

Measuring the length of the head can be carried out by measuring the distance between the snout and the ear-bone.

This can also be carried out as the fish passes by at a fixed or variable speed.

The estimation of the position of the brain in relation to the longitudinal direction of the device can be carried out based on the position of the snout of the fish, which is detected by the sensing appliance. From the brain's 10 estimated position, in relation to the longitudinal direction of the device, the blow unit 15 is controlled so that the blow is aimed directly towards the estimated position of the brain.

15 In a preferred realization of the measuring appliance and the trigger implement of the blow appliance, a measuring arm, suspended so that it extends down between the conveyor belts, is used. A pulse transmitter of the rotational type is connected to this measuring arm. This 20 pulse transmitter is connected to the inlet of a programmable logic control unit. The trigger of the blow unit is connected to an outlet on the same control unit.

When the fish hits the measuring arm, the measuring arm starts its rotation. Then, two clocks start simultaneously 25 by the pulse transmitter sending a number of pulses that are dependent on the angle of deflection. The number of pulses is registered for one or more timeintervals. As the speed of the conveyor belt is known, the shape of the head can be calculated in the logic control unit, with a 30 gradientrelationship between measured height and one of the clocks. The trigger point for the blow unit is subsequently calculated and the blow is initiated when the second clock has arrived at the trigger point.

Claims

Claims

1. Method for slaughtering and exsanguination of fish, where a blow unit gives the fish a blow to the brain 5 region of the fish to slaughter or stun the fish, and where the stunned or slaughtered fish is subsequently bled with the aid of a exsanguination appliance, c h a r a c t e r i s e d i n the fish is fed forward in a device, and that the fish, in an area in the 10 longitudinal direction of the device, passes a sensing appliance where the position of the brain of the fish in relation to the longitudinal direction of the device is determined such that the blow unit of the device is controlled to effect a blow towards the brain region of 15 the fish, and where the exsanguination appliance of the device is guided to effect a penetrating of a blood vessel or cutting of the fish's gill arches.

2. Method in accordance with claim 1, 20 c h a r a c t e r i s e d i n that the fish is fed forward in the device with the aid of a number of conveyor belts that hold the fish in a given position in relation to sensing appliance, blow unit and exsanguination appliance. 3. Method in accordance with one of the claims 1-2, c h a r a c t e r i s e d i n that the fish is fed forward in a vertical position, i.e. preferably that the fish lies on its back down towards the gliding-bed and 30 with the gut upwards.

4. Method in accordance with one of the claims 1-3, c h a r a c t e r i s e d i n that the position of the brain in the head of the fish is determined from the shape 35 of the head.

5. Method in accordance with claim 4, c h a r a c t e r i s e d i n that the shape of the head is determined by the height of the head being measured at one or more distances from the snout.

6. Method in accordance with claim 4, c h a r a c t e r i s e d i n that the shape of the head is determined in that the breadth of the head is measured at one or more distances from the snout.

7. Method in accordance with one of the claims 4-6, c h a r a c t e r i s e d i n that the shape of the head is determined as the fish passes the sensing appliance at a fixed or variable speed.

8. Method in accordance with one of the claims 1-3, c h a r a c t e r i s e d i n that the position of the brain in the head of the fish is determined from the length of the head.

9. Method in accordance with claim 8, c h a r a c t e r i s e d i n that the length of the head is measured by measuring the distance between the snout and the ear-bone.

10. Method in accordance with claim 8 or 9, c h a r a c t e r i s e d i n that the length of the head is measured as the fish passes the sensing appliance at a fixed or variable speed.

11. Method in accordance with one of the claims 1-lO' c h a r a c t e r i s e d i n that the position of the brain in relation to the longitudinal direction of the device is determined from the position of the snout of the 35 fish or position of the ear-bone and shape of the head.

12. Method in accordance with one of the claims l-10, c h a r a c t e r i s e d i n that the location of the brain in relation to the longitudinal direction of the device is determined from the snout position or ear-bone 5 position and the length of the head.

13. Method in accordance with one of the claims l-11, c h a r a c t e r i s e d i n that the location of the brain is determinded in relation to the position of an eye 10 of the fish.

14. Device (10) for slaughtering and exsanguination of fish, where the fish is given, by a blow unit (15), a blow to the brain region of the fish to kill or stun the fish, 15 and where the stunned or slaughtered fish is subsequently bled with the help of a exsanguination appliance (16) , c h a r a c t e r i s e d i n that the appliance (10) comprises: 20 - a number of conveyor belts (11) for forward feeding of fish in the longitudinal direction of the appliance (10), - a sensing appliance (14) that determines the shape of the head of the fish and or the length of the head of the 25 fish, - a control unit (14b) that, based on information from the sensing appliance (14), estimates the position of the brain region in the head of the fish and which based on 30 information about the position of the brain in the head and about the position of the fish in the longitudinal direction of the device (10), where the control unit (14b) controls the blow unit (15) to direct an accurate blow to the brain region of the fish, and where the control unit

(14b) guides the exsanguination unit (16) to penetrate a blood vessel or to cut one or more of the fish's gill arches. 5 15. Device (10) in accordance with claim 14, c h a r a c t e r i s e d i n that the device comprises a number of pressure bodies (12) which, by way of the conveyor belts (11), press against the side of the fish.

10 16. Device (10) in accordance with claim 15, c h a r a c t e r i s e d i n that the pressure bodies (12) are synchronized so that the fish is centred in the device (10).

15 17. Device (10) in accordance with one of the claims 19 16, c h a r a c t e r i s e d i n that the device (10) comprises a gliding-bed (13).

18. Device (10) in accordance with one of the claims 14 20 17, c h a r a c t e r i s e d i n that the conveyor belt (11), pressure bodies (12) and gliding-bed (13) cooperate to ensure a forward feeding of the fish in the longitudinal direction of the device (10) at the same time as the fish is kept still, in a given position.

19. Device (10) in accordance with claim 18, c h a r a c t e r i s e d i n that the position of the fish is vertical.

30 20. Device (10) in accordance with claim 19, c h a r a c t e r i s e d i n that the head of the fish lies against the gliding-bed (13).

21. Device (10) in accordance with one of the claims 14 20, c h a r a c t e r i s e d i n that there are openings in the gliding-bed (13) for insertion of the blow unit (15).

22. Device (10) in accordance with one of claim 14, c h a r a c t e r i s e d i n that the exsanguination appliance (16) comprises a blade-formed hook-shaped object with internal knife-edge.

23. Device (10) in accordance with claim 22, c h a r a c t e r i s e d i n that the exsanguination appliance (16) is guided so that the blade penetrates a blood vessel, or is forced in beyond the gill arches as 15 it is positioned in a direction which is approximately tangential to the gill arch, subsequently to be turned in a direction which is generally perpendicular to the gill arch, thereafter to be pulled out again through a defined trajectory which ensures that the gill arch(es) is (are) 20 caught in the hook-shaped object and get(s) cut.

24. Device (10) in accordance with claim 14, c h a r a c t e r i s e d i n that the cutting unit of the exsanguination appliance (16) comprises a jack-knife 25 that unfolds after the blade has passed the gill arch, and where the gill arches are cut when the blade pulls out again. 25. Device (10) in accordance with claim 14, 30 c h a r a c t e r i s e d i n that the exsanguination appliance (16) encompasses a blade-formed hook-shaped object without an internal knife edge, to ensure that the gill arches are pulled out of the fish.

26. Device (JO) in accordance with claim 14, c h a r a c t e r i s e d i n that the device comprises two conveyor belts (11).

5 27. Device (10) in accordance with claim 14, c h a r a c t e r i s e d i n that the device comprises three conveyor belts where between two of these is an opening through which a sensor can determine the position of the ear bone of the fish.

28. Method for slaughtering and exsanguination of fish, substantially as hereinbefore described with reference to the accompanying drawings.

29. Device for slaughtering and exsanguination of fish, substantially as hereinbefore described with reference to the accompanying drawings.