WO2010082834A1

WO2010082834A1 - Device for collection of waste material from a fish farming cage

Info

Publication number: WO2010082834A1
Application number: PCT/NO2010/000018
Authority: WO
Inventors: Einar Holmefjord
Original assignee: Einar Holmefjord
Priority date: 2009-01-16
Filing date: 2010-01-18
Publication date: 2010-07-22
Also published as: NO329813B1; NO20090258L

Abstract

A device is described for collection of waste such as dead fish or dying fish and the like from a funnel -formed bottom part (20) of a fish farming cage (2), comprising a hose (10) that runs from the bottom part (20) and up to the surface for the sucking up of the waste mixed with water, and comprising a system to form a suction effect through the hose. The device is characterised in that an inlet (24) of the hose comprises a blocking piece (60) in the form of a flexible, extended body that is fastened with its one end adjoining the inlet, said blocking piece (60) as a consequence of the suction effect is pulled/sucked upwards inside the hose (10) and thus opens the inlet for waste/dead fish (40) when the pumping up takes place, and when the pumping up stops, the blocking piece (60) is arranged to be pulled downward by a downward flow of water through the hose, and covers and shuts the inlet (24) of the hose (10). The device can be applied to prevent live fish swimming in through the inlet of the funnel/hose to hide when the collector 1 is in stand-by mode in the cage.

Description

DEVICE FOR COLLECTION OF WASTE MATERIAL FROM A FISH FARMING CAGE

The present invention relates to a device for collection of waste material, such as dead or dying fish and the like, from a funnel-shaped bottom part in a fish farming cage, comprising a hose that runs from the bottom part and up to the surface for the sucking up of the waste material mixed with water and comprising a system to form a suction effect through the hose as described in the introduction of the subsequent claim 1. The invention also relates to applications .

Prior art

Removal of dead fish, wasted feed material and faeces from a farming cage used in fish farming is a necessary task in the daily operation of a fish farming installation. The sizes of the net cages used today, the need for rationalisation and automation and an increased focus and demand for health, safety and the environment (HSE) of the operators of fish farming installations require use of systems that can be operated as independently as possible of human labour. With increasing focus on the health and welfare of the fish from the authorities and the consumers, it is, at the same time, important that all the operations that are carried out on a fish farm installation look after the welfare of the fish and that unnecessary suffering and stress for the fish are avoided. In the removal of dead fish/wasted feed material/faeces it is therefore an important aspect that live fish which stay in the cage are influenced by this operation to the smallest extent possible, if at all.

Figure 1 shows a previously known collection system 1 for dead fish/wasted feed material/faeces 40 from a fish farming cage 2, which comprises a funnel 20 that is placed at the bottom of a net bag 4. A housing, often with a conical shape, is placed at the bottom and with a sidewise formed opening for inflow of water, dead fish and dying fish. The housing is formed at the top with an opening for connection of a hose through which the sinking waste material from the bottom of the cage is pumped up to the surface, as indicated in the figures. A connection with an inlet for compressed air fixes a hose 10 (spiral or flat hose or pipe) to the pointed end (the cone) 22 of the funnel 20 and from there to the surface of the water 30. At the connecting point for the hose 10 to the cone 22 in the funnel 20 there is an opening 24 in the cone where dead fish 40 that are collected in the funnel can be sucked in. A compressor supplies compressed air to the funnel, which sucks water, feed material, faeces and dead fish through the opening in the funnel and up in the hose 10 to the surface of the cage/surface of the water 30. The collector 1 can be used up to several times a day and it normally takes 3-5 minutes with compressed air for each operation. The rest of the time the collector 1 lies in stand-by mode inside the cage.

Larger fish, such as salmon stay away from the funnel at the bottom of the cage and there is therefore no, or a very small risk, for live large fish being sucked up with the dead fish during the pumping. However, the problem with the known device is that small fish, or fry of, for example, salmon, trout or cod, are pulled into the funnel and go up into the hose to hide. This leads to small, live fish also being pumped up together with dead fish with the use of the known collecting system 1. The pumping up of live fish results in unwanted loss of small fish, reduced fish welfare, stress, damage to the fish and, in many cases, increased mortality. Larger fish of certain fish species, such as cod, also can have a tendency to pull into the cone housing and block this up.

This is a particularly big problem in fish farming cages where fish of different sizes are mixed in the same farming net. This is, for example, the case when small wrasse are in the same cage as large salmon. Addition of wrasse for the removal of salmon lice parasite in fish farming cages is becoming more and more common and is an alternative to an input of delousing agents such as chemicals. The wrasse eat lice that sit on the salmon and are an effective and natural alternative to the use of chemical treatment of the salmon against lice.

Lately, fish farmers, particularly along the Norwegian west coast, have experienced that salmon lice build up resistance to traditional treatment and this is considered to be one of the greatest threats to salmon farming in Norway and abroad. The use of wrasse seems to be the best alternative and is expected to increase considerably. Wrasse (as fry from salmon, trout and cod) are in the habit of having a hiding place in their habitat and it is common that fish farmers who use wrasse hang out pipe ends and the like in the cages so that the fish have somewhere to hide. In cages with the above mentioned collecting system the wrasse go down in the funnel and up in the hose. Similar to small fry of other species, this leads to the wrasse being pumped up together with the dead fish with the above mentioned negative effects.

To avoid the problem of small fish that are sucked up in the hose 10 by the above mentioned collecting system 1 for dead fish, systems with different shutting means for the suction opening 24 in the cone of the funnel have been developed previously. These systems all presuppose the use of rope from the surface to the funnel to be able to open and shut the opening 24 of the funnel 20 during pumping with the help of, for example, a cover. The disadvantage with these systems is that the ropes can get stuck, something that makes it impossible to open the funnel for the pumping out of dead fish when this becomes necessary.

Summary

The device according to the invention is characterised in that an inlet to the hose comprising a blocking piece in the form of a flexible, extended body that is fastened with one end adjoining the inlet, said blocking piece, as a consequence of the suction effect, is pulled/sucked up inside the hose and thus opens the inlet for waste material/dead fish when the pumping up takes place, and when the pumping up ceases, the blocking piece is set up to be pulled downward by a downward flow of water through the hose, and covers and blocks the inlet of the hose.

According to a preferred embodiment, the body has the shape of an extended casing, the one opening rim of which is fastened round the internal circumference of the hose, just above said inlet, and in its suction position the casing is turned inside out upward in the hose and forms an open passage for the waste material from the outlet and up through the hose, and under said downward flow of water the casing is turned inside out downward and covers and shuts the inlet.

According to yet another preferred embodiment the blocking piece has the (body) shape of a wire mesh collector, preferably multi-sided, such as a square shape, the one edge side of which is fastened to the inside of the hose just above the inlet.

According to yet another preferred embodiment the blocking piece is made with length and breadth dimensions sufficient to cover the inlet when it is pulled down.

According to yet another preferred embodiment the flexible blocking piece is made from a rubber material, a woven cloth, a filter cloth, and the like, and is fastened with its peripheral circumference to the inside of the hose adjacent to, and just above, said inlet.

According to yet another preferred embodiment, weights are sewn into/tied onto the flexible blocking piece which increases the weight of the blocking piece and contributes to the blocking piece changing position in the collection hose after the pumping of dead fish is finished and that the opening is properly closed for smaller fish.

According to yet another preferred embodiment the hose is a spiral hose, a flat hose or a pipe. The inlet is preferably connected to a housing part with a conical shape with a sidewise shaped inlet opening for inflow of water/dead fish, and the housing part is shaped at the top with a opening for connection of the hose through which the waste material that sinks down is pumped from the bottom of the cage and up to the surface. According to yet another preferred embodiment the housing part is an integrated part of the bottom funnel. When the blocking piece is a wire mesh collector, the edge of one of its sides is fastened to the inside or the outside of the hose/housing part just above the inlet of the hose/housing part.

According to the invention, the device is applied to prevent live fish from swimming in through the inlet of the funnel/hose to hide when the collector is in stand-by- mode in the cage. It is also used to prevent larger fish from swimming in through the inlet and into the funnel/hose to hide and block the flow of water and waste material through the hose when the suction operation starts .

The present invention shall now be described with the help of the embodiment examples with reference to the enclosed figures, in which

Figure 1 which is described initially, shows the known method for a collection system for dead fish/wasted feed material/faeces with the help of a funnel with an inlet or a suction opening for dead fish/wasted feed material/faeces that have been collected in the funnel. The funnel is placed in the bottom part of a fish farming cage where dead fish are sucked in through an inlet (a suction opening) with the help of, for example, compressed air and are transported through a hose up to the surface of the cage .

Figure 2 shows the placing of a stocking/casing in the funnel when the pump is turned off and is in a waiting mode or stand-by mode. Figure 3 shows the placing of the stocking/casing in an operative position at the sucking up of dead fish.

Figure 4 shows the situation when the pumping operation is completed and the stocking/casing moves down in the hose and shuts the opening of the funnel for small fish.

Figure 5 is a vertical section through the lower part of the collector which is placed at the bottom of the cage and shows the placing of the stocking/casing in operative position at the sucking up of dead fish/faeces/wasted feed material. The arrows show the flow of compressed air and stream of water, respectively, during the pumping up operation.

Figure 6 is a vertical section through the lower part of the collector which is placed at the bottom of the cage and shows the situation after the pump operation is over and the stocking/casing has moved down in the hose and shuts the opening of the funnel for small fish. The arrow indicates the flow of water immediately after the pumping has stopped.

Figure 7 shows a perspective of the cone-formed housing with the flexible blocking piece indicated in the two positions. In the one position, where it has folded itself over the opening 24 in the side wall of the housing with an unbroken line, and with a dotted line when the emptying by the pump is carried out and it is turned inside out up into the pipe 10 with the help of the liquid flow.

Detailed description

The funnel 20 comprises an inner housing part 80 and an outer conical wall of the funnel 20. The funnel 20 is preferably manufactured from plastic or another suitable material. The housing part 80 has an inlet or a suction opening 24 in the lower part as shown in detail in figure 5. Dead or dying fish, wasted feed material and faeces 40 which have collected in the funnel can be sucked through the inlet 24 and be transported through a short passage channel 82 (indicated by the dotted line in figure 5) in the housing part 80 and up to an associated hose 10. The hose 10 that, for example, is a spiral hose, a flat hose or a pipe, extends from the top of the funnel to the top of the cage/water surface 30 (illustrated in figure 1) where it preferably is connected to a collecting container with a sieve (not shown) for further treatment of the waste. Dead fish, wasted feed material and/or faeces are transported through the hose 10 with the stream of water. The stream of water for the pumping is preferably generated with the help of compressed air such as compressed air from a compressor. The compressed air line 70 runs from the top of the cage to the transition area 84 between the hose and the funnel, respectively, just above the transition area 84 in the hose 10 as indicated in the figures 3-5.

The blocking piece 60 according to the present invention is a new and improved technical solution which is developed to prevent that fish of a smaller size (small fish) can swim into the inlet/suction opening 24 of the collector 1 to hide inside the housing. The blocking piece 60 has the shape of a flexible casing, i.e. it is open in both ends so that the water can pass through. It can also be compared with and described as corresponding to a stocking with no foot . The blocking piece is fastened with its one opening rim around the internal circumference of the hose 10 just above said inlet, or in the transition area 84 between the housing part 80 of the funnel 20 and the hose 10 (figure 5) . During said downward flow of water, the casing is "turned inside out" downward and it covers and closes the inlet. The casing is of such a length that it covers the inlet opening when it is turned downward.

The blocking piece is preferably a flexible, extended casing body fastened with its peripheral circumference to the inside of the hose 10 adjoining the housing 80.

According to an alternative solution, the blocking piece has the form of a wire mesh collector, preferably multi- sided, such as a square form, the one edge side of which is fastened to the inside of the hose just above the inlet. In this shape the blocking piece is formed with length and breadth dimensions sufficient to cover the inlet when it hangs downward or is pulled down.

When the blocking piece is a wire mesh collector, the one edge side can be fastened either to the inside or the outside of the hose/housing part just above the inlet to the hose/housing part.

The blocking piece 60 is preferably made from a suitable material, for example, rubber, soft plastic or a woven material (fabric, cloth, material) filter cloth that gives the desired characteristics so that it is flexible, water tolerant and relatively durable in the stream of water. At the same time the material must be compatible with fish farming .

Means for fastening of the blocking piece 60 to the inside of the hose/funnel can be, for example, welding, gluing, sewing with thread or other suitable methods for fastening.

When fluid (particularly air) is injected through the pressure pipe 70, an upward flow of fluid is set up that drags with it, or turns inside out, the blocking piece 60 upward and opens the inlet channel through the casing (figures 3 and 5) so that the liquid flows in through the inlet, through the inside out turned casing and further up through the hose, while when the injection of fluid stops, a downward flow of liquid arises that drags with it the blocking piece 60 downward, it settles in the inlet 24 and closes this, i.e. the suction opening 24 of the housing part 80 (figures 4,6 and 7) .

In stand-by mode, and when the pump that drives the sucking up of dead fish 40 (and/or wasted feed material and/or faeces) is turned off, the blocking piece 60 hangs down and blocks the opening 24 in the funnel 20 as shown in figures 2 and 3, and figures 6 and 7, respectively. Thereby, smaller fish can not swim into or enter into the suction opening 24 of the funnel 2, the passage channel 82 or the hose 10 to hide.

To prevent the fish (wrasse) from swimming into the cone housing 80, the blocking piece 60 does not need to provide a complete seal of the opening 24. It is sufficient that the fish realise that the inlet is closed. Thereby the blocking piece may also be in the form of strips.

When compressed air 70 that, for example, can be generated as compressed air from a compressor placed on the fish farming installation or ashore, is switched on and led through the pressure fluid pipe 70 in the hose 10, the blocking piece 60 is pulled up in the pipe/hose 10 so that the dead fish/wasted feed material/faeces 40 can pass through and be sucked up through the suction opening 24 in the housing part 80 of the funnel. This pumping up situation and the position of the blocking piece 60 is illustrated in figure 3 and figure 5. The arrows in figures 3 and 5 indicate the stream of water and the direction of the suction up of dead fish, wasted feed material and/or faeces 40 and also the air flow of compressed air that comes out of the compressed air line 70.

When the collecting pump is switched off, a stream of water thus arises in the opposite direction to the pumped flow because the water flows back as a consequence of gravitational forces, as illustrated in figure 4 and figure 6, respectively, with the help of the arrows. The blocking piece 60 follows the stream of water, falls down again and blocks the suction opening 24 for smaller fish.

The application of the blocking piece 60 according to the invention does not presuppose the use of a rope or other mechanical aids. Application of the blocking piece 60 at the pumping up of dead fish/wasted feed material/faeces 40 requires no particular handling or control operation from the top of the cage either.

In a preferred embodiment, weights are sewn into/tied onto the blocking piece 60, for example, small metal parts or stones at the edge (the seam) of the blocking piece 60 which increase the weight of the blocking piece 60. This contributes to the blocking piece 60 changing position in the collector 1 after the pumping up of dead fish/wasted feed material/faeces 40 has ceased, as described above and closes the opening 24 in a secure, reliable way for smaller fish. The dimensions and mass of the weights must be adapted so that they represent no physical barrier during the pumping of dead fish/wasted feed material/faeces 40.

In a preferred embodiment, the hose 10 is made from a normal tip or a pipe (can be operated manually) which is well known in the industry. The dimensions of the blocking piece 60 must be adjusted to the dimensions of the opening 24 of the funnel 20 and to the diameter of the hose so that it optimally covers/closes the opening 24. When the suction hose has a diameter of the order of 10-20 cm, the blocking casing has a corresponding diameter so that the upper rim edge of the casing is fastened around the inside of the hose, just above the inlet 24, and it is longer than said diameter. When the blocking piece is a wire mesh collector, its breadth and length dimensions are such that it covers the opening .

It is preferred that the collecting operation is driven with the help of a compressor which has sufficient capacity for the sucking up operation, for example 4-7.5 kW that supplies 2-1200 litres air per minute from 3-10 bar. However, it is also possible to use other known pumping technologies in connection with the present invention providing that they are suitable for this purpose. The pumping up operation can initially be controlled manually or automatically, for example, by timer control of the pump or in connection to a sensor system that registers dead fish/wasted feed material/faeces 40 at the bottom of the cage. As the position of the blocking piece 60, and thus the shutting mechanism according to the present invention is only controlled by the liquid/fluid stream in the collecting system 1, there is no need for a separate control of the suction opening 24. This is a clear advantage with regard to the previously known technology where a rope is applied to shut and open a cover fitted onto the suction opening 24 of the funnel 20.

It is desirable that the features in the present invention as described here can be combined in any combination within the inventive frame.

Claims

1. Device for collection of waste material such as dead or dying fish and the like from a funnel- formed bottom part (20) in a fish farming cage (2) , comprising a hose

(10) that runs from the bottom part (20) and up to the surface for sucking up the waste material mixed with the water, and comprising a system for forming a suction effect through the hose, characterised in that an inlet (24) to the hose comprises a blocking piece (60) in the form of a flexible, extended body that is fastened with its one end adjoining to the inlet, said blocking piece (60) as a consequence of the suction effect is pulled/sucked upward inside the hose (10) and thus opens the inlet for waste/dead fish (40) when the pumping up takes place, and when the pumping up stops, the blocking piece (60) is arranged to be pulled downward by a downward stream of water through the hose and covers and shuts the inlet (24) of the hose (10) .

2. Device according to claim 1, characterised in that the body has the form of an extended casing, the one opening rim of which is fastened around the internal circumference of the hose just above said inlet, and in its suction position the casing is turned inside out upward in the hose and forms an open passage for the waste

(40) from the outlet and up through the hose, and during said downward flow of water, the casing is turned inside out downward and covers and shuts the inlet (24) .

3. Device according to claims 1-2, characterised in that the blocking piece is (the body) in the form of a wire mesh collector, preferably multi-sided, such as a square shape, the one edge side of which is fastened to the inside of the hose just above the inlet, or in the form of strips .

4. Device according to claims 1-3, characterised in that the blocking piece is shaped with length and breadth dimensions sufficient to cover the inlet when it is pulled down.

5. Device according to claims 1-4, characterised in that the flexible blocking piece (60) is made from a rubber material, a woven material, a filter cloth and the like, and is fastened with its peripheral circumference to the inside of the hose (10) adjoining to and just above said inlet (24) .

6. Device according to one of the preceding claims, characterised in that there are weights sewn into/tied onto the flexible blocking piece (60) which increase the weight of the blocking piece (60) and contribute to the blocking piece (60) changing position in the collecting hose (1) after the pumping up of dead fish (40) has finished and that the opening (24) is properly shut to smaller fish.

7. Device according to claims 1-6, characterised in that the hose (10) is a spiral hose, a flat hose or a pipe.

8. Device according to one of the preceding claims, characterised in that the inlet is connected to a housing part with a conical shape with a sidewise shaped inlet opening for inflow of water/dead fish, and the housing part is formed at the top with an opening for connection of the hose through which the sinking waste is pumped from the bottom of the cage to the surface of the water.

9. Device according to one of the preceding claims, characterised in that the housing part constitutes an integrated part of the bottom funnel.

10. Device according to one of the preceding claims, characterised in that when the blocking piece is a wire mesh collector, its one side edge is fastened to the inside or the outside of the hose/housing part just above the inlet to the hose/housing part.

11. Application of the device according to claims 1-9, to prevent that live fish swim in through the inlet of the funnel/hose to hide when the collector 1 is in stand-by mode in the cage.

12. Application of the device according to claims 1-9, to prevent larger fish from swimming in through the inlet and into the funnel/hose to hide and block the hose when the sucking up of water and waste material starts .