Device for collecting faeces, feed particles and dead fish from a bottom of a fish enclosure and method for use of the device

Abstract

A collection device (1) for collecting faeces, particles and dead fish from a fish enclosure, comprising: - a house (2) comprising an inlet (21) and an outlet (23); - a collector (3) fluidly connected to the house (2) and fluidly connected to a riser (33); - a collection surface (44) to which the house (2) is fastened, and - a first gas pipe (61) fluidly connected to the collector (3) adjacent to the house (2) The house (2) comprises a plurality of inlets (21) and a barrier (5) at each inlet (21). The barrier (5) comprises a displaceable sliding gate (53) adapted to be displaced between an open position and a closed position. The sliding gate (53) in the closed position is adapted to allow faeces and feed particles to pass through the sliding gate (53). A method for operating the collection device (1) is disclosed.

Description

[0001] DEVICE FOR COLLECTING FAECES, FEED PARTICLES AND DEAD FISH FROM A BOTTOM OF A FISH ENCLOSURE AND METHOD FOR USE OF THE DEVICE

[0002] The invention concerns a device for collection of faeces, feed particles and dead fish from a fish enclosure. The fish enclosure may be a floating fish enclosure such as a net pen or a closed fish pen. The fish enclosure may be a land-based fish tank. More particularly the collection device is provided with a plurality of inlets for efficient removal of faeces, feed particles and dead fish around the whole circumference of the collection device. The collection device may comprise two inlets, three inlets, four inlets and even more than four inlets. Even more particularly the collection device may comprise a barrier in front of the inlet for selective collection of faeces and feed particles but not allowing for collection of dead fish through the inlet when the barrier is in a closed position. In an open position the barrier allows for the passage of faeces, feed particles and dead fish in the same inlet. The collection device is provided with a supply of gas. The supply of gas is part of an air lifting pump system which generates a flow of water from the inlet of the collection device through a riser and to a surface. The collected faeces, feed particles and dead fish are transported by the flow of water from the inlet to the surface for treatment.

[0003] Systems for collecting faeces, feed particles and dead fish from the bottom of a fish cage is disclosed in e.g., patent document NO344657B1. Such systems are provided with an air lifting pump system which generates a flow of water from the collection device through a tube and to a surface. Such systems remove faeces, feed particles and dead fish from a collection surface in front of the inlet. However, faeces, feed particles and even dead fish may rest on surfaces of the collection device forming backwater and therefore are

[0004] P31602PC00 description and claimsoutside the suction area of the inlet. Thereby, the collecting device does not remove such material in an efficient way.

[0005] The inlet opening of known collecting devices is large enough to allow passage of dead fish. This means that also live fish may pass through the entrance and may be pumped up to the surface. At the surface dead fish is separated from the water flow by a grid arrangement. As live fish may have been trapped by the collecting device, it is necessary to inspect the grid arrangement for live fish. Therefore, the air lifting pump system cannot be operated continuously day and night. However, for efficient removal of faeces and feed particles it will be beneficial with a continuous operation that does not require continuous monitoring.

[0006] The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

[0007] The object is achieved through features, which are specified in the description below and in the claims that follow.

[0008] The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

[0009] In a first aspect the invention relates more particularly to a collection device for collecting faeces, feed particles and dead fish from a fish enclosure, the collection device comprises: - a house comprising an inlet and an outlet;

[0010] - a collector fluidly connected to the house at a connection end and fluidly connected to a riser;

[0011] - a collection surface to which the house is fastened, and

[0012] - a first gas pipe fluidly connected to the collector adjacent to the house.

[0013] The house comprises a plurality of inlets. The collection device comprises a barrier at each inlet. The barrier comprises a displaceable sliding gate. The barrier is adapted to displace the sliding gate between an open position and a closed position. The sliding gate in the closed position is adapted to allow faeces and feed particles to pass through the sliding gate.

[0014] P31602PC00 description and claimsThe collection device may comprise two inlets. The collection device may comprise three inlets. The collection device may comprise four inlets. The collection device may comprise more than four inlets. The collection device comprising two inlets may comprise inlets that are facing in opposite directions. Thereby each inlet will cover a sector of 180° of the collection surface. The collection device comprising three inlets may comprise inlets that are facing in directions 120° apart. Thereby each inlet will cover a sector of 120° of the collection surface. The collection device comprising four inlets may comprise inlets that are facing in directions 90° apart. Thereby each inlet will cover a sector of 90° of the collection surface. The collection device according to the invention will cover more of the collection surface compared to a collection device with one inlet only.

[0015] The house may comprise a plurality of internal channels between the plurality of inlets and the outlet. Each channel may have an outlet. Thereby the house may have a plurality of internal outlets.

[0016] The collector may comprise a plurality of collector conduits at the connection end. Each collector conduit may be in fluid communication with one internal outlet. Each of the plurality of the collector conduits may be provided with a separate gas pipe. Each collector conduit may be in fluid communication with the riser.

[0017] The separate gas pipe to each collector conduit provides a means for activating one collector conduit and thereby one inlet at a time while leaving the other collector conduits and inlets in a passive state.

[0018] The separate gas pipe to each collector conduit provides a means for activating a number of collector conduits and a number of inlets at a time while leaving some collector conduits and inlets in a passive state.

[0019] The collector at the connection end may comprise an internal partition. The internal partition may split the collector into collector conduits. A diagonal partition splits the collector into two collector conduits. A star shaped partition may split the collector into three, four or more collector conduits depending on the number of arms on the "star".

[0020] P31602PC00 description and claimsThe collector conduit may comprise a collector tube. Each collector tube may be detachable for cleaning and maintenance.

[0021] A plurality of collector tubes may be in fluid communication with the riser through a manifold. The manifold may be detachable for cleaning and maintenance.

[0022] The collection surface may comprise a central portion and a circumferential portion. The circumferential portion may taper towards a first circumferential flange. Faeces, feed particles and dead fish may slide down the tapering circumferential portion towards the central portion and one of the inlets.

[0023] The riser may be a tube with an internal diameter of e.g., 200 mm. Each collector conduit may have an internal cross-sectional area that is comparable to or identical to the internal cross-sectional area of the riser.

[0024] The collection device may comprise a fastening device, wherein the fastening device may comprise a first fastening structure and a second fastening structure adapted to be releasable fastened to the first fastening structure, and the first fastening structure may comprise the collection surface. A net or a water-tight material such as tarpaulin at the bottom of the fish enclosure may be fastened between the first fastening structure and the second fastening structure. The second fastening structure may be fastened to the net or to the water-tight material. Thereby the first fastening structure may be released from the second fastening structure and the collecting device may be lifted up and out of the fish enclosure for cleaning and maintenance.

[0025] The collection device may comprise a central connection plate connected to the house, the central connection plate may be adapted to be releasable fastened to the first fastening structure, and the central connection plate forms part of the collection surface. Thereby parts of the collection device may be lifted up and out of the fish enclosure for cleaning and maintenance while the fastening device remains at the bottom of the fish enclosure.

[0026] The collection surface may comprise a recess, and the central connection plate may be adapted to be releasable fastened to the first fastening structure within the recess.

[0027] P31602PC00 description and claimsThereby, the collection surface is kept smooth such that the faeces and the feed particles flow unobstructed towards the inlet.

[0028] The second fastening structure may be conical and comprising a downward pointing apex. The second fastening structure may comprise an additional weight such as balls of metal or other suitable heavy objects within the second fastening structure.

[0029] The second fastening structure may comprise a rounded bottom. Thereby, the collection device may be used in a fish enclosure positioned in shallow waters, such as a Scottish loch.

[0030] The collection device may comprise a central connection plate connected to the house, and the connection plate may be adapted to be releasable fastened to the fish enclosure. The central connection plate may be fastened to the bottom of a land-based tank.

[0031] The collection device may comprise a ridge between two adjacent inlets. The ridge may be detachable fastened to the collection surface. The ridge may be a tapering ridge. The ridge may taper towards two inlets. The ridge may taper from the house towards the circumferential portion such that the ridge is lowest at the circumferential portion. The advantage of the ridge is that faeces, feed pellets and dead fish are guided towards the inlet and the ridge prevents backwaters between the inlets.

[0032] The sliding gate may comprise spaced apart bars. The spaced apart bars form between them passages that are large enough for the faeces and the feed particles to pass through while dead fish and live fish are prevented from entering the inlet.

[0033] The barrier may comprise an operation mechanism supplied with gas for operation via a second gas pipe. The gas may be provided from the surface by e.g., a compressor. Valves may be opened or closed for selectively opening and closing of the barriers.

[0034] The barrier may comprise a gas connection between the operation mechanism and the collector conduit. Thereby, the gas used for operating the operational mechanism, i.e., keep the barrier in the open state, is further used for pumping water through the inlet.

[0035] P31602PC00 description and claimsIn a second aspect the invention relates more particularly to a method for operating a collection device. The method comprises to:

[0036] - provide the collection device according to the first aspect;

[0037] - provide a source of compressed gas;

[0038] - provide a valve arrangement provided with a plurality of valves and adapted for guiding compressed gas selectively to one of a first gas pipe and a second gas pipe; and

[0039] - supply compressed gas to the valve arrangement.

[0040] The method may comprise in a first condition of operation to open a first valve and guide compressed gas to one selected first gas pipe only. Thereby, only one inlet will be active in collecting faeces and feed particles as the barrier in front of the inlet is in a closed state.

[0041] The method may comprise to after a selected time, to close the first valve, open a second valve and guide compressed gas to another selected first gas pipe only. Thereby, an adjacent inlet becomes active and faeces and feed particles in front of the adjacent inlet will be collected. This may be repeated such that all inlets become active one by one, and feaces and feed particles are collected from the whole circumference around the house.

[0042] The method may comprise in a second condition of operation to open a third valve and guide compressed gas to one selected second gas pipe only. Thereby, the barrier connected to the selected gas pipe is activated, the sliding gate is displaced upwards, and the barrier is in the open state. The gas provided to the barrier may be guided to a collector conduit to activate the air lift pump. Any dead fish in front of the barrier will be sucked into the collection device and transported to the surface through the riser.

[0043] The method may comprise to after a selected time, to close the third valve, open a fourth valve and guide compressed gas to another selected second gas pipe only. Thereby, the barrier receiving gas through the third valve will return to the closed state and an adjacent barrier will be activated such that the adjacent barrier is in the open state. This may be repeated such that all barriers become open one by one, and dead fish are collected from the whole circumference around the house. As only one barrier is in the open state

[0044] P31602PC00 description and claimsat a time, the collecting device will not pump only water through an inlet with less fluid resistance.

[0045] In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

[0046] Fig. 1 shows in a perspective view a collection device;

[0047] Fig. 2 shows in a perspective view a second embodiment of the collection device;

[0048] Fig. 3 shows in a different scale the same as figure 2 and with one embodiment of a second fastening structure;

[0049] Fig. 4 shows the same as figure 3 and with another embodiment of the second fastening structure;

[0050] Fig. 5 shows in a perspective view a third embodiment of the collection device;

[0051] Fig. 6 shows in a larger scale a barrier;

[0052] Fig. 7 shows in a different scale an alternative embodiment of the barrier;

[0053] Fig. 8 shows a sectional drawing of a variant of the embodiment shown in figure 5 without the barrier;

[0054] Figs. 9A-B show in a perspective view a fourth embodiment of the collection device with three inlets (A) and in a larger scale a top view / sectional drawing of the embodiment (B); and

[0055] Figs. 10A-B show in a perspective view a fifth embodiment of the collection device with four inlets (A) and in a larger scale a top view / sectional drawing of the embodiment (B).

[0056] Any positional indications refer to the position shown in the figures.

[0057] P31602PC00 description and claimsIn the figures, same or corresponding elements are indicated by same reference numerals. For clarity reasons, some elements may in some of the figures be with-out reference numerals.

[0058] A person skilled in the art will understand that the figures are just principal drawings. The relative proportions of individual elements may also be distorted.

[0059] In the figures, the reference numeral 1 indicates a collection device. The collection device 1 comprises a house 2 and a collector 3 fluidly connected to the house 2. The house 2 comprises a plurality of inlets 21, a plurality of outlets 23 and a plurality of internal channels 25 between the inlets 21 and the outlets 23. Each inlet 21 is connected to a separate outlet 23 via a separate channel 25.

[0060] The collector 3 comprises a connection end 30 and an opposite riser 33. The collector 3 is releasably connected to the house 2 at a connection end 30. The collector 3 is at the connection end 30 split into a plurality of collector conduits 31 by partitions 34. One partition 34 is shown in figure 1. The partition 34 separates the collector 3 into two collector conduits 31. Each outlet 23 is connected to a separate collector conduit 31. The plurality of collector conduits 31 are terminated at a distance from the house 2 such that the plurality of collector conduits 31 are joined into one common riser 33. Figure 1 shows a partly cut away section of the collector 3 to depict the plurality of collector conduits 31.

[0061] The collection device 1 further comprises a fastening device 4. The fastening device 4 is used for fastening the collection device 1 to a bottom portion of a fish enclosure (not shown). The fastening device 4 comprises a first fastening structure 41 and a second fastening structure 42. The first fastening structure 41 is in figure 1 depicted like a circular soup plate with a circumferential first flange 411 at a first rim 412. The second fastening structure 42 is in figure 1 depicted with a conical shape. The second fastening structure 42 comprises a circumferential second flange 421 at a second rim 422. The bottom portion of the fish enclosure may comprise a tarpaulin or other water-tight material. The fastening device 4 fits in a through hole in the bottom portion, and the material of the bottom portion is fixed between the first flange 411 and the second flange 421. The first flange 411 is releasably fastened to the second flange 421 by bolts (not shown) positioned

[0062] P31602PC00 description and claimsin through holes as known in the art. As an alternative, the bottom portion of the fish enclosure comprises a net, and the net is fixed between the first flange 411 and the second flange 421.

[0063] The second fastening structure 42 may comprise a weight (not shown). The weight may be positioned in an apex 425 of the conical shaped second fastening structure 42. The weight may comprise metal balls or other suitable heavy objects. The first fastening structure 41 and the second fastening structure 42 may comprise a plastic material for easy cleaning.

[0064] The first fastening structure 41 comprises a collection surface 44 facing away from the second fastening structure 42. The collection surface 44 comprises a central portion 45 and a circumferential portion 46. The circumferential portion 46 tapers towards the first flange 411.

[0065] The house 2 is fixed to the collection surface 44 at the central portion 45. The plurality of inlets 41 are off set from a center 9 of the collection device 1. Each inlet 41 is facing a collection area 47 which is a sector of the central portion 45 and a sector of the circumferential portion 46.

[0066] Each inlet 21 is provided with a displaceable barrier 5. The barrier 5 will be explained in further detail in relation to figures 6 and 7. The barrier 5 is adapted to be in a closed state to close the inlet 21 such that faeces and feed particles (not shown) may pass through the barrier 5 but fish (not shown) are not allowed to pass the barrier 5. The barrier 5 is further adapted to be in an open state to allow the passage of fish as well. In figure 1 the barrier 5 is depicted in an open state.

[0067] The collection device 1 further comprises a plurality of gas pipes 6. A plurality of first gas pipes 61 are in fluid communication with the plurality of collector conduits 31 at the connection end 30, one first gas pipe 61 for each collector conduit 31. A plurality of second gas pipes 62 are in fluid communication with the plurality of barriers 5, one second gas pipe 62 for each barrier 5. A plurality of third gas pipes connects fluidly the plurality of barriers 5 to the plurality of collector conduits 31 (e.g., see figure 2). One third gas pipe 63

[0068] P31602PC00 description and claimsconnects one barrier 5 to one collector conduit 31. The second gas pipe 62 is only depicted partly to simplify the figure. The first gas pipe 61 is supplied with gas from a first gas source (not shown) at a surface (not shown). The gas may be air. The first gas source may be a compressor. The second gas pipe 62 is supplied with gas from a second gas source at the surface. The gas may be air. The second gas source may be a compressor. The first gas source and the second gas source may be the same gas source.

[0069] The collection device 1 is shown with a tapering ridge 7. The ridge 7 tapers towards two inlets 21. The ridge tapers from the house 2 towards the circumferential portion 46 such that the ridge 7 is lowest at the circumferential portion 46.

[0070] A second embodiment of the collection device is shown in figure 2. The house 2 is connected to a central connection plate 26. The central connection plate 26 fits into a corresponding recess 27 in the collection surface 44. The central connection plate 26 is detachable fastened to the first fastening structure 41 by bolts (not shown) or other fastening means in corresponding holes 28 in a third flange 261 and in the recess 27. Figure 2 depicts the barrier 5 in a closed state.

[0071] The central connection plate 26 may also fit into a corresponding recess at the bottom of a fish tank (not shown). The fish tank comprises a solid bottom and the fastening device 4 is superflous. The connection plate 26 may be detachable connected to the bottom of the fish tank.

[0072] The embodiment shown in figure 2 is shown without the ridge 7. In a variant of this embodiment, the variant comprises the ridge 7 as shown in figure 1.

[0073] The embodiment shown in figure 2 is depicted with two inlets 21 and two collector conduits 31.

[0074] Figure 3 shows an embodiment with the same second fastening structure 42 as shown in figure 1 and with the same first fastening structure 41 as shown in figure 2.

[0075] Figure 4 shows an embodiment with the same first fastening structure 41 as shown in figures 2 and 3. The second fastening structure 42 deviates from the second fastening

[0076] P31602PC00 description and claimsstructure 42 shown in figure 1 as the second fastening structure 42 is not conical but with a rounded bottom 427.

[0077] Figure 5 shows an alternative embodiment of the collector conduits 31. The collector conduits 31 comprise separate collector tubes 3. Each collector tube 32 is in a first end portion 320 in fluid communication with one outlet 23 and the second end connection 329 is in fluid communication with a manifold 35. The manifold 35 is in fluid communication with the riser 33. The manifold 35 comprises a plurality of branches 351. The manifold 35 is in figure 5 depicted with two branches 351 and the manifold 35 forms a Y-shaped connection. The manifold 35 may be releasably fastened to the riser 33. The manifold 35 may be releasably fastened to each of the collector tubes 32.

[0078] The barrier 5 is shown in a closed state in figure 6. The barrier 5 comprises a fastening frame 51, a portcullis like sliding gate 53, a guide 55 and an operation mechanism 57 adapted to open and close the barrier 5 by displacing the sliding gate 53. The operation mechanism 57 is within the guide 55. The frame 51 forms a lower portion 510 and an upper portion 519. The guide 55 is fastened to the frame 51 at the upper portion 519. The frame 51 forms a barrier inlet 52 (see figure 7).

[0079] The guide 55 comprises a guide beam 551 provided with a plurality of spaced apart guide holes 553. The holes 553 are aligned in one row. The guide 55 comprises a guide box 555 which houses the operation mechanism 57. The operation mechanism 57 is displaceable within the guide box 555.

[0080] The sliding gate 53 is shown as a plurality of spaced apart bars 531 organised in a row. The bars 531 are guided by the corresponding guide holes 553 in the guide 55. Each guide hole 553 fits tightly around the bar 531 but with sufficient space between the guide hole 553 and the bar 531 to allow for displacement of the bar 531 within the guide hole 553. Thereby any debris that may accumulate on the surface of the bar 531 is scraped off as the bar 531 is displaced upwards relative to the guide beam 551.

[0081] The operation mechanism 57 is supplied with gas from the second gas pipe 62. The operation mechanism 57 depicted in figure 6 comprises a gas chamber 571 which is in fluid

[0082] P31602PC00 description and claimscommunication with the gas pipe 62. The operation mechanism 57 comprises a weight chamber 573 housing a weight (not shown). The third gas pipe 63 is in fluid communication with the collector conduit 31. The gas chamber 571 and the weight chamber 573 is fastened to the sliding gate 53 such that the gas chamber 571, the weight chamber 573 and the sliding gate 53 are displaced together as one unit. When the gas chamber 571 is filled with gas, the operation mechanism 57 is due to increased buoyancy displaced upwards until the operation mechanism 57 abuts an internal upper face 556 of the guide box 555. The barrier inlet 52 is then fully open as seen in figure 7. The guide box 555 comprises a side wall 557 facing the house 2. The side wall 557 comprises two through slits 558. The second gas pipe 62 and the third gas pipe 63 are flexible and will be displaced together with the operation mechanism 57 within the slits 558.

[0083] When the gas supply is turned off and most of the gas in the gas chamber 571 has been evacuated to the collector conduit 31, buoyancy is reduced, and the weight is sufficient to lower the sliding gate 53 such that the barrier 5 becomes closed.

[0084] The fastening frame 51 may be fastened to the house 2 by bolts.

[0085] An alternative embodiment of the barrier 5 is depicted in figure 7. The gas chamber 571 is expandable. When gas is provided to the gas chamber 571 through the second gas pipe 62, the gas chamber 571 expands and increases the buoyancy of the operation mechanism 57. The operation mechanism 57 further comprises at least one resilient member 574 between the gas chamber 571 and the internal upper face 556. The resilient member 574 may be a spring 575 as depicted in figure 7. The operation mechanism 57 may comprise a plurality of resilient members 574 or springs 575 which are either fastened to the internal upper face 556 or at least abut the internal upper face 556. When the gas pressure in the expandable gas chamber 571 is increased, the expandable gas chamber 571 lifts the sliding gate 53 and compresses the resilient member 574 such that the barrier 5 is opened. When the gas pressure in the expandable gas chamber 571 is decreased, the resilient member 574 forces the expandable gas chamber 571 and the sliding gate 53 downwards to close the barrier 5.

[0086] P31602PC00 description and claimsIn an alternative embodiment (not shown) the resilient member 574 comprises an expandable return gas chamber. When the gas pressure in the expandable gas chamber 571 is increased, the return gas chamber is not provided with gas and the return gas chamber collapses. The expandable gas chamber 571 lifts the sliding gate 53 such that the barrier 5 is opened. When the gas pressure in the expandable gas chamber 571 is not provided with gas and the return gas chamber is provided with gas and expands, the expandable gas chamber 571 collapses and the increased volume of the return gas chamber forces the expandable gas chamber 571 and the sliding gate 53 downwards to close the barrier 5.

[0087] The channel 25 is best seen in figure 8. The embodiment shown in figure 8 is not provided with a barrier 5 in front of the inlet 21.

[0088] The collection device 1 may be provided with three inlets 21 and three collector tubes 32 as seen in figure 9A. In this embodiment the ridges 7 are shown as detachable ridges 7. Each ridge 7 is connected to a ridge base 71. As shown in figure 9B the ridge base 71 may be releasable fastened with bolts 73 to the first fastening structure 41 and the central connection plate 26.

[0089] The collection device 1 may be provided with four inlets 21 and four collector tubes 32 as seen in figures 10A-B. The collection device 1 in this embodiment is shown provided with two lifting straps 11. The lifting straps 11 aid in lowering the collection device 1 within the fish enclosure such as a net pen. The lifting straps 11 aid in lifting the collection device 1 out of the fish enclosure if the collection device 1 is in need of maintenance. All the disclosed embodiments may be provided with lifting straps 11 as shown in figure 10A.

[0090] The embodiments shown in figures 9A-B and 10A-B are provided with fastening eyes 13 adjacent to the inlet 21. The fastening frame 51 may be fastened to the fastening eyes 13.

[0091] The collection device 1 allows for removing faeces and pellets continuously day and night from a fish enclosure. A valve arrangement (not shown) at the surface is adapted to guide compressed air selectively to one of the first gas pipes 61 and the second gas pipes 62.

[0092] P31602PC00 description and claimsIn a first condition of operation the barrier 5 is in the closed state and the valves to the second gas pipes 62 are closed. Compressed air is supplied to a selected collector conduit 31 or collector tube 32 through a selected first gas pipe 61. The released gas within the collector conduit 31 ascends to the surface through the riser 33 and activate the air lifting pump. Faeces and feed particles in front of the inlet 21 on the collection area 47 are sucked through the sliding gate 53 and follow the ascending water within the riser 33. After a time, that may be a predetermined time, the valve closes, and another selected first gas pipe 61 receives compressed gas. In this manner all the inlets 21 in the house 2 are activated in series, and the process is repeated. Only faeces and feed particles are collected and there is no need for monitoring for dead or alive fish. The operation may be ongoing day and night. Only small amounts of faeces and feed particles will accumulate on the collection area before they are removed.

[0093] It is beneficial if the internal cross-sectional area of the collector conduit 31 is similar to or identical to the internal cross-sectional area of the riser 33 as this provide for an effective action of the air lifting pump. If two inlets are active at the same time, the suction in front of each inlet 21 is reduced, or one inlet 21 takes precedence over the other inlet 21.

[0094] In a second condition of operation the valves to the first gas pipes 61 are closed and the operation is monitored. Compressed air is supplied to a selected barrier 5 through a selected second gas pipe 62. The barrier 5 is then in the open state. The gas passes through the operation mechanism 57 and is guided to the collector conduit 31 through the third gas pipe 63. The released gas within the collector conduit 31 ascends to the surface through the riser 33 and activate the air lifting pump. Any faeces and feed particles in front of the inlet 21 on the collection area 47 are sucked through the inlet 21 and follow the ascending water within the riser 33. Any dead fish in front of the inlet 21 is sucked through the inlet 21 and follow the ascending water within the riser 33. After a time, that may be a predetermined time, the valve closes, and another selected second gas pipe 62 receives compressed gas. In this manner all the barriers 5 are activated in series, and the process may thereafter be repeated or stopped.

[0095] P31602PC00 description and claimsIt is beneficial if the internal cross-sectional area of the collector conduit 31 is similar to or identical to the internal cross-sectional area of the riser 33 as this provide for an effective action of the air lifting pump. If two inlets 21 are open at the same time, one inlet 21 receives a dead fish and the other inlet 21 does not, then water will flow more easily in the empty inlet 21 such that suction is not sufficient to bring the dead fish in the other inlet 21 into the riser 33. Thereby, the air lift pump will only pump water while dead fish remains at the collection device 1.

[0096] As explained in the description, individual parts of the collecting device 1 are releasable or detachable fastened to each other. This ease cleaning of the collection device 1. Maintenance is made more easy, e.g., replacement of broken parts.

[0097] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0098] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0099] P31602PC00 description and claims

Claims

C l a i m s1. A collection device (1) for collecting faeces, feed particles and dead fish from a fish enclosure, the collection device (1) comprises:- a house (2) comprising an inlet (21) and an outlet (23);- a collector (3) fluidly connected to the house (2) at a connection end (30) and fluidly connected to a riser (33);- a collection surface (44) to which the house (2) is fastened, and- a first gas pipe (61) fluidly connected to the collector (3) adjacent to the house (2),c h a r a c t e r i s e d i n thatthe house (2) comprises a plurality of inlets (21), andthe collection device (1) comprises a barrier (5) at each inlet (21), the barrier (5) comprises a displaceable sliding gate (53), the barrier (5) is adapted to displace the sliding gate (53) between an open position and a closed position, and wherein the sliding gate (53) in the closed position is adapted to allow faeces and feed particles to pass through the sliding gate (53).

2. The collection device according to claim 1, wherein the house (2) comprises a plurality of internal channels (25) between the plurality of inlets (21) and the outlet (23).

3. The collection device (1) according to any one of the preceding claims, wherein - the collector (3) comprises a plurality of collector conduits (31) at the connection end (30);- each collector conduit (31) is in fluid communication with one outlet (23);- each collector conduit (31) is in fluid communication with one outlet (23); - each of the plurality of the collector conduits (31) are provided with a separate first gas pipe (61); and- each collector conduit (31) is in fluid communication with the riser (33).

4. The collection device (1) according to claim 3, wherein the collector (3) at the connection end (30) comprises an internal partition (34).P31602PC00 description and claims5. The collection device (1) according to claim 3, wherein the collector conduit (31) comprises a collector tube (32).

6. The collection device (1) according to claim 5, wherein a plurality of collector tubes (32) is in fluid communication with the riser (33) through a manifold (35).

7. The collection device (1) according to any one of the preceding claims, wherein the collection surface (44) comprises a central portion (45) and a circumferential portion (46).

8. The collection device (1) according to any one of the preceding claims, wherein the collection device (1) comprises a fastening device, wherein the fastening device comprises a first fastening structure (41) and a second fastening structure (42) adapted to be releasable fastened to the first fastening structure (41), and the first fastening structure (41) comprises the collection surface (44).

9. The collection device (1) according to claim 8, wherein the collection device (1) comprises a central connection plate (26) connected to the house (2), the central connection plate (26) is adapted to be releasable fastened to the first fastening structure (41), and the central connection plate (26) forms part of the collection surface (44).

10. The collection device (1) according to claim 9, wherein the collection surface (44) comprises a recess (27), and the central connection plate (26) is adapted to be releasable fastened to the first fastening structure (41) within the recess (27).

11. The collection device (1) according to claim 8, wherein the second fastening structure (42) is conical and comprises a downward pointing apex (425).

12. The collection device (1) according to claim 8, wherein the second fastening structure (42) comprises a rounded bottom (427).

13. The collection device (1) according to any one of claims 1 to 7, wherein the collection device (1) comprises a central connection plate (26) connected to theP31602PC00 description and claimshouse (2), and the connection plate (26) is adapted to be releasable fastened to the fish enclosure.

14. The collection device (1) according to any one of the preceding claims, wherein the collection device (1) comprises a ridge (7) between two adjacent inlets (21).

15. The collection device (1) according to any one of the preceding claims, wherein the sliding gate (53) comprises spaced apart bars (531).

16. The collection device (1) according to any one of the preceding claims, wherein the barrier (5) comprises an operation mechanism (57) supplied with gas for operation via a second gas pipe (62).

17. The collection device (1) according to claim 16, wherein the barrier (5) comprises a gas connection (63) between the operation mechanism (57) and the collector conduit (31).

18. A method for operating a collection device (1),c h a r a c t e r i s e d i n that the method comprises to:- provide the collection device (1) according to any one of claims 1 to 17;- provide a source of compressed gas;- provide a valve arrangement provided with a plurality of valves and adapted for guiding compressed gas selectively to one of a first gas pipe (61) and a second gas pipe (62); and- supply compressed gas to the valve arrangement.

19. The method according to claim 18, wherein the method comprises in a first condition of operation to open a first valve and guide compressed gas to one selected first gas pipe (61) only.

20. The method according to claim 19, wherein the method comprises to after a selected time, to close the first valve, open a second valve and guide compressed gas to another selected first gas pipe (61) only.P31602PC00 description and claims21. The method according to claim 18, wherein the method comprises in a second condition of operation to open a third valve and guide compressed gas to one selected second gas pipe (62) only.

22. The method according to claim 21, wherein the method comprises to after a se- lected time, to close the third valve, open a fourth valve and guide compressed gas to another selected second gas pipe (62) only.P31602PC00 description and claims

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