DK201970523A1 - Apparatus for evacuating solid matter from an aqueous environment - Google Patents

Abstract

Apparatus for evacuating solid matter from an aqueous environment, in particular fish from cages in a fish farm, where said apparatus comprises: - a suction arrangement connected to - a flexible suction hose, where a length of said flexible suction hose is stored in a storage facility allowing a first length of the flexible suction hose to be paid out or retracted relative to the injection pump, by means of - a hose dispensing/retracting device, said hose dispensing/retracting device having a channel for guiding the flexible suction hose through the hose dispensing/retracting device, and where engagement means are provided in said channel for engaging the outer side of the flexible suction hose, in order to feed out or retract the flexible suction hose; - a suction head provided at a free end of the suction end opposite the end of the suction hose connected to the injection pump.

Description

DK 2019 70523 A1 1 Apparatus for evacuating solid matter from an aqueous environment Field of the Invention The present invention is directed to an apparatus for evacuating solid matter from an aqueous environment, in particular fish, including dead fish, from cages in a fish farm.

Furthermore, the invention is also directed at a fish farm cage where such an apparatus is used as well as a method for evacuating solid matter from an aqueous environment such as fish from a fish farm.

Background of the Invention Fish farming is becoming an increasingly important factor in providing enough food stuffs for an ever-growing population. Fish farms are widespread around the globe and some of them are very large, i.e. have a large number of cages or pens which need to be tended by personnel.

Due to the severe environment in which the fish farms normally are placed, i.e. either in far Northern reaches or in far Southern reaches the work on the fish farm requiring human interaction may be relatively dangerous due to the working conditions in these areas.

Furthermore, it is desirable to minimize the amount of investment in the cages in order to bring the prices on the product down as well as minimizing the manual labour cost involved in raising the fish.

One of the challenges in raising fish in fish farms is to keep the cages/pens clean such that illness, parasites etc. do not spread to otherwise healthy fish in the fish cage or in neighbouring fish cages. For these reasons hygienic requirements are relatively high in order to maintain a healthy fish stock in a fish farm environment.

Another challenge is to remove for example dead fish and other debris from the water enclosed by the net of a fish cage, such that this unwanted and foreign matter is re- moved as swiftly and fast as possible in order to obtain a clean and safe environment for the fish in the fish cage.

DK 2019 70523 A1 2 In the art it is known to install relatively large and expensive structures in each fish cage where the structure includes a pipe leading to the bottom of the fish cage where an inlet is provided such that any solid matter such as dead fish etc. which sinks through the water may be removed by suction through the fixed pipe. These systems have a number of drawbacks such as for example that each fish cage needs to have such a device installed and due to the geometrical configuration of the fish cage this structure needs to be mounted substantially in a central part of the fish cage in order to be able to reach to the bottom of the fish cage where solid matter influenced by gravi- ty will accumulate. Furthermore, due to the motion of the fish cage caused by swells and waves and wind the net from which the fish cages are made may rub against the fixed structure thereby increasing wear and tear on the structure and shortening the life expectancy for the fish netting. If a tear occurs in the fish netting, the fish netting needs to be repaired or replaced and at the same time there is a great risk that the fish stock may escape resulting in a sub- stantial loss to the fish farmer.

Object of the Invention Consequently, it is desirable to provide a system which addresses these drawbacks and at the same is faster, more user-friendly and has less impact on the fish cages as such. Description of the Invention The invention addresses this by providing an apparatus for evacuating solid matter from an aqueous environment, in particular fish from cages in a fish farm, where said apparatus comprises: - a suction arrangement connected to - a flexible suction hose, where a length of said flexible suction hose is stored in a storage facility allowing a first length of the flexible suction hose to be paid out or retracted relative to the injection pump, by means of

DK 2019 70523 A1 3 - a hose dispensing/retracting device, said hose dispensing/retracting device having a channel for guiding the flexible suction hose through the hose dispens- ing/retracting device, and where engagement means are provided in said channel for engaging the outer side of the flexible suction hose, in order to feed out or retract the flexible suction hose; - a suction head provided at a free end of the suction end opposite the end of the suction hose connected to the injection pump.

The apparatus provides a number of advantages which will be explained.

Firstly, by providing a suction arrangement in connection with a flexible suction hose having a suction head it is possible to direct the suction head by means of the flexible suction hose to any desired position inside the fish cage.

Simply by arranging the apparatus next to a fish cage the flexible suction hose may be lowered into the water inside the fish cage and guided to the position where the solid matter rests on the bottom of the fish cage in order to remove the solid matter.

In order to help or facilitate the guiding and positioning of the suction head, the suc- tion head may be provided with a camera, allowing the operator to get an overview of the position and amount of solid matter, and the relative position of the suction head, in order to facilitate a more efficient evacuation of the solid mater.

As fish cages may vary in size and depth of the net, the storage of the flexible suction hose on a storage facility allows that the length of a hose may be varied from fish cage to fish cage without substantial changes to the apparatus. The hose is simply paid more or less out from the storage facility and as such the apparatus is very versatile and able to address the requirements for removing solid matter such as dead fish from most commercial fish farms.

In the initial test carried out with a prototype of this arrangement the flexible suction hose had a length of 30 meters which has proved more than sufficient to reach all de- sired points inside a commercial fish cage.

DK 2019 70523 A1 4 In a further advantageous embodiment the hose dispensing/retracting device is provid- ed with one or more rollers, which one or more rollers are arranged in the channel for engaging the flexible suction hose, where the one or more rollers are provided with motors connected to a control unit, such that the rollers may be rotated in both direc- tions around an axle, where rotation of a roller causes the flexible suction hose to be moved relative to the dispensing/retracting device. Particularly the provision of a hose dispensing/retracting device provides substantial advantages in that the manual handling of a relatively long and cumbersome flexible suction hose may be automated by providing an apparatus where rollers will guide the flexible suction hose through the apparatus. Advantageously the apparatus for dispensing and retracting the flexible suction hose will be arranged adjacent the periphery of the fish cage, for example on the buoyant body of the fish cage or adjacent the side of a service boat. In this manner it is very easy and very controllable to dispense the flexible suction hose from the storage facili- ty on the service boat or on the buoyant member into the fish cage and allow the flexi- ble suction hose with its attached suction head to slide along the net to the bottom of the fish cage.

As the suction hose is flexible it will readily follow the movement of the fish cage and as such will not create tear and wear on the netting as such. In order to dispense or retract a flexible hose from the apparatus the operator just needs to make sure that the rollers are engaged with the flexible suction hose and thereafter activate the motors such that the rollers will rotate thereby forcing the flexi- ble hose to move relative to the dispensing/retracting device. Depending on the orientation of the rotation of the rollers it is clear that the flexible suction hose will either be dispensed or retracted. In this manner a single operator may dispense and retract a flexible hose without any substantial effort. In a still further advantageous embodiment of the invention the flexible suction hose is provided with a corrugated outer surface forming first ridges and valleys encircling

DK 2019 70523 A1 the flexible suction hose along the length of the hose, and where the one or more roll- ers are provided with second ridges on an outer surface, such that the second ridges are spaced such that the second ridges in use engage the valleys on the suction hose.

5 The provision of ridges and valleys encircling the flexible suction hose in combination with corresponding ridges on the rollers provides for a very firm and strong grip be- tween the rollers and flexible suction hose.

Furthermore, by providing a plurality of rollers more or less encircling a large part of the diameter of the flexible suction hose it is ensured that a firm grip is provided be- tween the rollers and the flexible suction hose such that the driving forces from the rollers may be transmitted through the flexible suction hose without damaging the hose in the process.

The engagement means in the shape of rollers may be powered by any conventional means such as for example hydraulic or electrical means, but may also be operated mechanically or manually, for example by a cranking mechanism. This may be im- portant if the hydraulic or electrical means should fail such that it is still possible to retract the flexible suction hose from the fish cage in order to return to base and have the apparatus repaired. This may also be advantageous in other situations.

In a further advantageous embodiment storage facility for the flexible suction hose a reel is provided onto which the flexible suction hose may be wound up and wound off.

It is desirable to be able to store the flexible suction hose on a reel having a substan- tially large diameter in order not to create a kink or bend and other undesirable dam- age to the flexible suction hose and at the same time by storing it on a reel it is easy simply by rotating the reel to wind up the flexible suction hose being retracted from the fish cage by the dispensing/retracting device and vice versa also to dispense from the reel simply by unwinding the hose from the reel.

In a still further advantageous embodiment of the invention the suction arrangement as such comprises a primary pump which primary pump has access to a source of liquid, and where said pump ejects water under pressure into an injector, creating a flow of

DK 2019 70523 A1 6 liquid from an injector suction inlet to an injector outlet, where the flexible suction hose is connected to said suction inlet. By providing an injector and creating a water flow through the injector such that an under-pressure is created in the flexible suction hose it is ensured that water will be sucked from the fish cage through the flexible suction hose and through the injector. In this manner the pump creating the force which acts on the water thereby sucking water and solid matter from the fish cage is not to come into contact with the solid matter which could give rise to excessive wear and tear in the pump as such or stop- page altogether. The pump is provided with its own water supply, for example in the shape of a suction hose being lowered into the water outside the fish cage.

The apparatus is in a further advantageous embodiment also supplied with a priming pump in the suction arrangement where the priming pump is in liquid communication with an injector, such that before the primary pump is activated creating suction in the injector and thereby the suction hose, the priming pump fills the system with liquid.

In order to move substantial amounts of water the primary pump may be very large and as such there is an advantage to fill the system with water before the primary pump is activated in order not to have the pump run dry which could create extra tear and wear in the primary pump.

For this reason the priming pump is provided in order to fill the system with water and allow a certain water pressure to be established in the suction arrangement before the primary pump gets up to full working speed. In this manner also cavitation and the detrimental effects cavitation may have on the pump blades etc. may be avoided.

In a still further advantageous embodiment of the invention a separator is provided, said separator being provided in liquid communication between the suction hose and the suction arrangement, or in liquid communication with the outlet of the suction arrangement, where said separator separates solid matter from the liquid.

DK 2019 70523 A1 7 The separator serves to separate water from solid matter, particularly fish. The separa- tor may also be constructed such that the separation stage will be able to distinguish between live fish and dead, and foreign solid matter. In this manner it is possible to recover any live fish which were accidentally sucked up by the device such that these may be reintroduced into the fishing cage. The solid matter may naturally be collected in a suitable storage means, and particularly for dead fish matter this may after suita- ble treatment be reused as a source of protein and fat.

The invention also discloses a fish farm cage comprising a net enclosing a volume of water, said net being connected to a buoyant body surrounding said volume of water, and where an apparatus according to any of claims 1 to 8 is arranged on the buoyant ring, such that the suction head on the flexible suction hose may be lowered and re- tracted from the volume of water.

Furthermore, the invention is directed to a method of evacuating solid matter from an aqueous environment such as fish and/or dead fish from a fish farm cage, wherein an apparatus according to any of claims 1 to 8 is used, where the method comprises the following steps: a. The apparatus is arranged next to the fish farm cage, such that the suction head and suction hose can be immersed into the water in the fish farm cage; b. the hose dispensing/retracting device is activated to dispense the flexible suc- tion hose and the suction head into the fish farm cage to a desired depth; c. the suction arrangement is activated, such that initially the suction arrange- ment is filled with water after which the suction of solid matter is performed; by the solid matter entering the suction head at the desired depth, the matter is transported with the water through the flexible hose to or through the suction arrangement; d. separating the solid matter from the water transported by the flexible suction hose.

Particularly by implementing the inventive apparatus in the method according to the present invention substantial savings may be achieved in carrying out this specific task in a fish farming operation compared to normal practice. The savings are particularly

DK 2019 70523 A1 8 achieved by the apparatus being a self-sufficient unit which may be operated by one operator which very quickly may feed out the suction hose at a desired fish farm and retract it after having evacuated the solid matter and thereafter proceed to the next fish cage.

By not having to operate a crane or the like in order to connect to a centrally placed pipe for sucking out the dead fish as is the case with the prior art devices substantial time savings are achieved as are substantial savings achieved by the cost of the much simpler sucking device according to the present invention compared to the more elab- orate constructions involving cranes and so forth. Particularly if there is a swell or wave action it may be difficult for a service boat to connect to the prior art centrally mounted suction structures whereas with the present invention, as the suction head and the flexible suction hose is dispensed directly over the side of the boat adjacent the inner side of the net of a fish cage, this procedure may be carried out substantially under any weather conditions. Description of the Drawing The invention will now be described with reference to the accompanying drawings wherein Figure 1 illustrates a cross-section through a fish farm cage; Figure 2a, 2b, 2c,2d illustrate the same apparatus seen from various angles; Figure 3 illustrates a schematic cross-section through an injector; Figure 4 and 5 illustrate the principles of the hose dispensing/retracting device; Figure 6 schematically illustrates the invention arranged on a service boat. Detailed Description of the Invention In figure 1 is schematically illustrated a cross-section through a cage (also called a pen) 1 of a fish farm positioned on a surface 2 of a body of water. The cage 1 com- prises a buoyant body 3 which surrounds a volume of water 4. Furthermore, a net 5 is suspended from the buoyant body 3 in order to enclose a volume of water 4.

DK 2019 70523 A1 9 Inside the cage in the volume of water 4 is where the rearing of fish takes place. As some of the fish die for various reasons, they will end up usually at the bottom of the net 5 and need to be collected. The invention provides a novel and inventive apparatus for collecting these dead fish and other debris, collective called solid matter, from the cage of the fish farm usually from the lowermost point of the net 5. The apparatus will be explained with reference to figure 2A, B, C and D. All the fig- ures 2A-2D illustrate the same apparatus seen from various angles. The apparatus comprises a suction head 10 connected to a free end of a flexible suction hose 12 such that the suction head 10 with the suction hose 12 may be lowered into the net 5 during operation. The other end of the flexible suction hose 12 not connected to the suction head 10 is connected to a suction arrangement 20. The suction arrangement comprises a frame structure 22 on and in which frame structure various pumps and controlling devices are arranged. The suction arrangement 20 further comprises an injector 24 which will be explained further with reference to figure 3. The injector 24 is connected by a pipe 26 to a pump

28. The pump 28 sucks water through a hose 30 in practice from the sea surrounding the fish cage such that the water sucked up through the hose 30 will be injected into the injector 24 by means of the pipe 26 which pipe 26 is arranged at an angle to the longitudinal axis of the injector 24 such that a water flow will be created inside the injector which water flow will go from the suction head 10 to an outlet hose 32 in the opposite end of the injector 24.

In this manner by activating the pump 28 suction will occur in the flexible suction hose 12 and at the suction head 10 such that any matter entering the suction head or in the vicinity of the suction head will be sucked into the suction head and transported through the flexible suction hose through the injector and expelled through the outlet

32. In this manner the pump itself will not be required to transport any solid matter in that the solid matter will only be present inside the suction head 10, the flexible suction hose 12, the injector 24 and the outlet hose 32.

DK 2019 70523 A1 10 Furthermore, the frame 22 is provided with a cabinet 34 in which the control system for controlling the apparatus is provided.

Turning to figure 3 a schematic overview of the principle of the invention is illustrat- ed. The primary pump 28 sucks water up from an unpolluted body of water through the inlet hose 30. Due to the action of the pump 28 this water is injected into the injec- tor 24 as illustrated by the arrow 36.

The pipe 26 is arranged at an angle relative to the longitudinal direction 38 of the in- jector 24. In this manner, due to the high velocity and volume of water being expelled from the primary pump 28 as indicated by the arrow 36 an under-pressure will occur downstream of the place where the pipe 26 is connected to the injector. This will cre- ate water movement as indicated by the arrow 40, whereby suction will occur in the flexible suction hose 12 and at the suction head 10.

The water being led to the outlet hose 32 is sucked by the suction head 10 through the hose 12 and as such the water will contain solid matter, typically in the form of dead fish and other debris. In order to separate the solid matter from the water a separator device may be arranged in connection with the outlet hose in order to allow clean wa- ter to leave the apparatus. In that manner the water being sucked out of the fish cage may be discharged directly into the sea next to the fish farm in that the water has been cleaned from undesirable matter.

As mentioned above the flexible suction hose may be paid out and retracted by means of a hose dispensing/retracting device. This device will now be explained with refer- ence to figure 4 and 5 which schematically illustrate the principle of a hose dispens- ing/retracting device.

In figure 4 is illustrated a cross-section through a device and in figure 5 is illustrated a schematic view of such a device. It is contemplated that the device 50 is mounted on the service boat immediately adjacent the side of the boat such that the flexible suction hose and the suction head may be paid out directly over the side of the boat and into the cage. The hose dispensing/retracting device 50 comprises a housing 52 in which

DK 2019 70523 A1 11 housing is provided a channel 54. The channel 54 is dimensioned such that the flexi- ble suction hose 12 may be arranged substantially inside the channel 54. On inner faces of the channel 54 are provided a number of rollers 56. In the illustrated embodiment three rollers are arranged. The rollers 56 are arranged such that they are able to engage the surface 13 of the flexible suction hose 12. By rotating the rollers 56 around longitudinal axis 56” it is possible due to the engagement between the rollers 56 and the surface of the flexible suction hose 13 to move the flexible suction hose 12 relative to the device 50 thereby dispensing or retracting suction hose depending on the direction of rotation of the rollers 56. In this embodiment three rollers are illustrat- ed 56 but any number of rollers such as for example two, five or more may be con- templated in order to ensure that there is a firm engagement between the surface 13 of the flexible suction hose 12 and the rollers 56 in order to be able to dispense and re- tract the flexible suction hose 12 in a controllable manner.

For the sake of good order it should be mentioned that the means for rotating the roll- ers 56 as well as control means for controlling the direction of rotating the rollers are not illustrated but it will be obvious to the skilled person to provide such means, for example by means of hydraulic pumps, electrical motors or the like in order to rotate the rollers.

It is also foreseen that the rollers 56 may be provided with resilient means urging the rollers into close engagement with the surface of the flexible suction hose 13.

In figure 5 is illustrated a schematic view of the hose dispensing/retracting device 50 where the flexible suction hose in this embodiment is provided with a corrugated outer surface such that first ridges and valleys are formed encircling the flexible suction hose along the length of the suction hose.

In this manner, by providing the rollers 56 with corresponding means it is possible to achieve a very firm engagement between the roller surface and the outer surface 13” of the flexible suction hose 12.

DK 2019 70523 A1 12 As may also be seen in figure 5 it is contemplated that more than one set of rollers 56 may be provided in the hose dispensing/retracting device whereby more force may be transmitted to the surface 13” of the flexible suction hose 12 such that the hose is not damaged which could occur due to the flexible nature of the suction hose.

Turning to figure 6 a very schematic illustration of the concept is presented. A cross- section through a service boat mounted with the apparatus according to the invention positioned next to a fish cage is illustrated. The service boat 100 is moored next to the buoyant body 3 of a cage 1. From the buoyant body 3 a net 5 is suspended encircling a volume of water 4 in which the fish is reared. On the service boat 100 is arranged an apparatus according to the invention where a suction hose 12 provided with a suction head 10 is lowered over the side of the service boat into the water 4 of the fish cage. The dispensing of the suction hose 12 is carried out by the hose dispensing and retracting device 50 where the suction hose 12 is stored on a reel 60 such that a relatively long length of suction hose 12 may be stored on the service boat 10. The suction hose is furthermore connected to the injector 24 which by means of a primary pump 28 leads a high energy water jet through the pipe 26 into the injector 24 thereby creating suction in the suction hose 12 whereby dead fish and other debris may be evacuated through the suction head 10 arranged inside the volume of water 4. As the water passes the injector 24 it is passed through a separator 62 where solid mat- ter such as fish and other debris is separated from the water after which the water by means of the outlet hose 32 is discarded back into the ocean. The invention has been explained with reference to a very specific example, but the inventive concept should only be limited by the appended claims.

Claims (11)

DK 2019 70523 A1 13 CLAIMS

1. Apparatus for evacuating solid matter from an aqueous environment, in particular fish from cages in a fish farm, where said apparatus comprises: - a suction arrangement connected to - a flexible suction hose, where a length of said flexible suction hose is stored in a storage facility allowing a first length of the flexible suction hose to be paid out or retracted relative to the injection pump, by means of - a hose dispensing/retracting device, said hose dispensing/retracting device having a channel for guiding the flexible suction hose through the hose dispens- ing/retracting device, and where engagement means are provided in said channel for engaging the outer side of the flexible suction hose, in order to feed out or retract the flexible suction hose; - a suction head provided at a free end of the suction end opposite the end of the suction hose connected to the injection pump.

2. Apparatus according to claim 1 wherein the hose dispensing/retracting device is provided with one or more rollers, which one or more rollers are arranged in the chan- nel for engaging the flexible suction hose, where the one or more rollers are provided with motors connected to a control unit, such that the rollers may be rotated in both directions around an axle, where rotation of a roller causes the flexible suction hose to be moved relative to the dispensing/retracting device.

3. Apparatus according to claim 2 wherein the flexible suction hose is provided with a corrugated outer surface forming first ridges and valleys encircling the flexible suction hose along the length of the hose, and where the one or more rollers are provided with second ridges on an outer surface, such that the second ridges are spaced such that the second ridges in use engage the valleys on the suction hose.

4. Apparatus according to claim 1 where the engagement means in the hose dispens- ing/retraction device are powered by hydraulic means, electrical means and/or may be operated mechanically/manually by a cranking mechanism.

DK 2019 70523 A1 14

5. Apparatus according to claim 1 wherein the storage facility of the flexible suction hose is a reel onto which the flexible suction hose may be wound up and wound off.

6. Apparatus according to claim 1 wherein the suction arrangement comprises a pri- mary pump, which primary pump has access to a source of liquid, and where said pump ejects water under pressure into an injector, creating a flow of liquid from an injector suction inlet to an injector outlet, where the flexible suction hose is connected to said suction inlet.

7. Apparatus according to claim 1 wherein the suction arrangement is provided with a priming pump in liquid communication with an injector, such that before the primary pump is activated creating suction in the injector and thereby the suction hose, the priming pump fills the system with liquid.

8. Apparatus according to claim 1 wherein a separator is provided, said separator be- ing provided in liquid communication between the suction hose and the suction ar- rangement, or in liquid communication with the outlet of the suction arrangement, where said separator separates solid matter from the liquid.

9. Fish-farm cage comprising a net enclosing a volume of water, said net being con- nected to a buoyant body surrounding said volume of water, and where an apparatus according to any of claims 1 to 8 is arranged on the buoyant ring, such that the suction head on the flexible suction hose may be lowered and retracted from the volume of water.

10. Method of evacuating solid matter from an aqueous environment such as fish and/or dead fish from a fish farm cage, wherein an apparatus according to any of claims 1 to 8 is used, where the method comprises the following steps: a. The apparatus is arranged next to the fish farm cage, such that the suction head and suction hose can be immersed into the water in the fish farm cage; b. the hose dispensing/retracting device is activated to dispense the flexible suc- tion hose and the suction head into the fish farm cage to a desired depth; c. the suction arrangement is activated, such that initially the suction arrange- ment is filled with water after which the suction of solid matter is performed; by the

DK 2019 70523 A1 15 solid matter entering the suction head at the desired depth, the matter is transported with the water through the flexible hose to or through the suction arrangement; d. separating the solid matter from the water transported by the flexible suction hose.

11. Method according to claim 10 further comprising the steps of: e. Deactivating the suction arrangement f. Retracting the flexible suction hose and suction head; g. Moving the apparatus to the next fish farm cage to be cleaned h. Repeating steps a. through c.