Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
  • A01K63/00—Receptacles for live fish, e.g. aquaria; Terraria
  • A01K63/10—Cleaning bottoms or walls of ponds or receptacles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/02—Cleaning by the force of jets or sprays
  • B08B3/024—Cleaning by means of spray elements moving over the surface to be cleaned
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/04—Cleaning involving contact with liquid
  • B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
  • B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B59/00—Hull protection specially adapted for vessels; Cleaning devices specially adapted for vessels
  • B63B59/06—Cleaning devices for hulls
  • B63B59/08—Cleaning devices for hulls of underwater surfaces while afloat
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
  • A01K61/00—Culture of aquatic animals
  • A01K61/60—Floating cultivation devices, e.g. rafts or floating fish-farms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B2203/00—Details of cleaning machines or methods involving the use or presence of liquid or steam
  • B08B2203/02—Details of machines or methods for cleaning by the force of jets or sprays
  • B08B2203/0288—Ultra or megasonic jets
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
  • Y02A40/80—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in fisheries management
  • Y02A40/81—Aquaculture, e.g. of fish

Definitions

• the present invention relates to a free-swimming and remotely controllable net washer for a fish farming net cage, comprising a framework equipped with several thrusters which guide the net washer in a body of water of the fish farming net cage, as well as several water nozzles for cleaning a submerged net in the fish farming net cage.
• the net cage usually consists of a net so that water flow through the net is allowed for the supply of oxygen to the fish, and for the fish to have natural resistance when it swims around in the net cage.
• the net In such an open facility, it will over time mean that the net is covered by an overgrowth so that the water through flow decreases and thus also the oxygen content, which also affects the fish's well-being and can result in lower slaughter weight.
• the net cage is often coated with impregnating agents to reduce fouling, but still the nets must be cleaned regularly. Cleaning can be done by picking up the entire net, after it has been emptied of fish, and brought up and sent to suitable cleaners for subsequent cleaning and impregnation. Thereafter, the net must be mounted in the fish farm facility and refilled with fish. This is, of course, extensive and costly work which both stresses and damages the fish. When the net is only cleaned sporadically, the growth will increase in hardness, and go from being a soft coating to hard growths. These hard and sharp particles will be able to settle in the gills of the fish during a conventional net wash.
• washing robots In recent years, it has also become common to use washing robots in the net. The washing robots are then moved from plant to plant, where they are lowered into the sea with cables and hoses to perform cleaning of the net. Such washing robots are usually equipped with rotating cleaning nozzles for high pressure rinsing of the net, or they can be equipped with rotating brushes. Many of these washing robots require considerable effort from personnel working at the fish farm, among other things to ensure the hanging and moving of the washing robot. However, there are also washing robots that can move around in the net cage on their own and that wash the net according to a specific pattern. This cleaning is relatively harsh on the net and its possible impregnation and will also stress the fish with noise and particle pollution.
• WO 2010048038 A2 relates to a device for cleaning subsea structures, connected to an ROV and with an ultrasonic transducer arranged next to a high-pressure water nozzle. Hot high-pressure water from the nozzle will improve cavitation since ultrasonic cleaning is stated to work better in water at increased temperature (130- 190 degrees Fahrenheit).
• a number of ultrasonic transducers are arranged at equal distances from each other or in a "bank or other group", and for two other embodiment forms it is stated that the propulsion system includes several propellers.
• the shape of the cleaning device is adapted to the shape of the subsea structure to be cleaned.
• US 2017081000 A1 relates to a device associated with an ROV for cleaning submarine structures using acoustic shock waves and narrow, mainly rectangular, high-pressure water nozzles.
• NO 20180461 A1 relates to a "fish farm cleaning robot" with a frame, a first and second set of thrusters, high-pressure nozzles and a nose assembly with a high- pressure water nozzle for access to hard-to-reach places. At least one ultrasonic transducer is provided to provide ambient data to a control unit.
• An object of the present invention is to provide a net washer which reduces energy requirements in connection with the cleaning of a net in a fish farming net cage.
• a further object is to provide a net washer which gently can clean a net in a fish farming net cage.
• the net washer according to the invention is a free-swimming ROV which comprises a pump with nozzles which distribute the water with low pressure and high-water flow, and which combined with ultrasonic transducers give pressure waves which will affect the water coming out of the spray nozzles.
• Ultrasound has been used as a means of preventing the establishment and growth of a variety of organisms.
• the advantages of ultrasound compared to, for example, chemical methods are that ultrasound is often relatively cheap and easy to generate, that it easily spreads over a large volume (e.g., water), and that it can be switched on and off immediately.
• a large volume e.g., water
• a free-swimming and remote- controlled net washer for a fish farming net cage comprising a framework equipped with several thrusters which control the net washer in a body of water of the fish farming cage, as well as several water nozzles for cleaning a submerged net in the fish farming net cage.
• the net washer is characterised in that said water nozzles are fixed, low-pressure water nozzles with a mouth opening facing out from a side surface of the net washer, where said water nozzles are placed side by side and at a mutual distance on the side surface of the net washer.
• the net washer comprises a water pump which supplies respective water nozzles with water which results in a water jet with low pressure and high-water flow, and an ultrasonic transducer is placed adjacent to each water nozzle and is arranged to send ultrasound to a water jet coming from the mouth opening. Said ultrasonic transducer is arranged to send a directional and cavitating sound wave towards the water jet coming from the mouth opening, and where the directional sound wave from said ultrasonic transducer and the water jet coming from the mouth opening to the water nozzle intersect at a distance from the side surface of the net washer which is less than 0.2 m.
• the net washer's water pump is driven by a motor, said water pump is arranged to collect water from the surrounding seawater, and where the water nozzles are connected to the water pump via a water line for supplying water.
• the net washer can also comprise one or more motor control units for controlling said thrusters.
• Said ultrasonic transducer is preferably located near the water nozzle and sends a directional sound wave towards the water jet that comes from the mouth opening, which leads to cavitation, whereupon the water implodes and releases particles which are stuck in the net in the fish farming net cage.
• the net washer can comprise a protruding frame member equipped with a water nozzle and an associated ultrasonic transducer.
• the water nozzle and the associated ultrasonic transducer can be rotatably mounted in the protruding frame part.
• the mouth opening of the respective water nozzle can have a rectangular form with a long and narrow shape.
• Figure 1 shows a net washer according to the invention, seen from a front side.
• Figure 2 shows the net washer according to the invention, seen from a rear side.
• Figure 3 shows the net washer according to the invention, seen from a top side.
• the net washer according to the invention is a free-swimming ROV with no connection to the surface other than a power cable, and which is equipped with a pump and water nozzles that distribute the water with low pressure and high water flow, which combined with ultrasonic transducers give pressure waves that will affect the water coming out of the spray nozzles.
• Ultrasound can be generated by all kinds of objects which vibrate at ultrasonic frequencies, i.e., above 20 kHz, and which can transmit this vibration to a medium which can propagate a sound wave, e.g., water.
• a sound wave e.g., water.
• transducers are used which can convert electrical energy into sound energy.
• Cavitation occurs in a liquid if the pressure at a given point becomes so low that the liquid evaporates and leaves a void (a "cavity") of gas. Cavitation can occur when an object moves through liquid at high speed, such as a propeller that rotates rapidly, or a sound wave can be so powerful that cavitation occurs in the part of the wave cycle where the pressure is lowest.
• the sound pressure must be above a certain threshold for a pressure wave to generate cavitation bubbles.
• This threshold depends on the frequency and gas content of the water. The threshold is generally lower for low frequencies and for the content of gas in the water.
• a sound wave that propagates in water will become weaker and die out as the distance to the sound source increases.
• the spread of the energy in the sound wave over a larger area means that the energy per area is reduced, furthermore some of the energy can be absorbed in the water while the wave propagates.
• the absorption depends on the temperature, pressure and salt content of the water.
• Other factors that can contribute are scattering of the sound wave by particles in the water, reflection of the wave in the water surface and on the seabed, deflection of the sound wave due to variations in sound speed, etc.
• the present invention comprises a net washer 10 which can swim freely around in the fish farming net cage (not shown) and which is comprised of a frame 12 and a side surface 20, to which the main components of the net washer are mounted.
• the net washer 10 is seen from what can be called a front side, in the sense that this front side will face the net to be washed.
• Figure 2 shows the opposite side than that shown in figure 1 , i.e., what can be called a back side and where the components of the net washer 10 appear.
• the back side is shown open, but the net washer 10 can, of course, comprise a housing which houses the components.
• Figure 3 shows the net washer according to the invention, as seen in the frame 12, i.e., as seen from above in figures 1 and 2.
• the free-swimming and remote-controlled net washer 10 comprises, as mentioned, a frame 12 and which is equipped with several thrusters 14 which control the net washer 10 in the water mass of the breeding cage.
• One or more thrusters 14 are connected to respective motor control units 28.
• the figures show three motor control units 28 and six thrusters 14 which provide thrust in three directions.
• the frame 12 is also equipped with buoyancy means 30 which can provide neutral or slightly positive or slightly negative buoyancy in the water.
• the buoyancy means 30 can be detachable for regulating the buoyancy.
• the frame 12 can be made of a material which provides the desired buoyancy in the water.
• the net washer 10 is further equipped with several water nozzles 16 for cleaning a submerged net in the fish farming net cage, where the water nozzles 16 are fixed, low pressure water nozzles with a mouth opening facing out from a side surface 20 of the net washer 10, i.e., the front as shown in figure 1. Furthermore, an ultrasound transducer 18 is located adjacent to each water nozzle 16, where the ultrasonic transducer 18 is arranged to transmit ultrasound towards a water jet coming from the mouth opening to the water nozzle 16. In the embodiment shown, the water nozzles 16 are shown with the mouth openings facing out from the side surface 20 on the front. As discussed, the components of the net washer can be housed in a housing and the back can optionally also comprise several water nozzles 16 which face out from a corresponding side surface on the back. Similarly for ultrasonic transducers 18.
• the net washer 10 comprises at least one water pump 22 which is driven by an associated motor 24.
• the water pump 22 collects water from the surrounding seawater, thus there is no need to supply water from the surface.
• the housing is designed so that water throughflow is allowed.
• the water nozzles 16 are connected to the water pump 22 via a water line 26 for supplying water.
• the water line 26 is usually a common water line which branches to each water nozzle 16.
• the water pump 22 supplies the respective water nozzles 16 with water which provides a water jet with low pressure and high-water flow out from the water nozzles 16.
• said water nozzles 16 can be placed side by side to each other and spaced apart on the side surface 20 of the net washer 10, and the water nozzles 16 can be placed in several rows so that a zigzag pattern of water nozzles 16 is formed on the side surface 20 of the net washer 10.
• the mouth opening to the respective water nozzle 16 is, as shown, rectangular in form with a long and narrow shape.
• the ultrasonic transducers 18 to be used are preferably directional ultrasonic transducers 18.
• Each ultrasonic transducer 18 is located near its water nozzle 16 and sends a directional sound wave towards the water jet coming from the mouth opening.
• the sound wave leads to cavitation, whereupon the water implodes and releases particles that are stuck in the net in the fish farming net cage.
• it is desirable that the distance between the water nozzle/transducer is not too great.
• the directional sound wave from said ultrasonic transducer 18 and the water jet coming from the mouth opening of the water nozzle 16 can therefore cross each other at a distance from the side surface 20 of the net washer 10 which is relatively small.
• the distance is less than 0.2 m.
• the net washer 10 can be provided with an additional water nozzle 16 and an additional ultrasonic transducer 18 located on a protruding portion 12a of the frame 12.
• the additional water nozzle 16 and the additional ultrasonic transducer 18 are designed similarly as described previously and connected to the same water pump 22.
• the additional water nozzle 16 and the additional ultrasonic transducer 18 are mounted to a plate 20', corresponding to the side surface 20.
• the plate 20' can be rotatably mounted in the protruding frame part 12a.

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• Life Sciences & Earth Sciences (AREA)
• Environmental Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Marine Sciences & Fisheries (AREA)
• Animal Husbandry (AREA)
• Biodiversity & Conservation Biology (AREA)
• Farming Of Fish And Shellfish (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=81383036

Family Applications (1)

Country Status (2)

Citations (3)

• 2020
  • 2020-10-29 NO NO20201182A patent/NO346571B1/no unknown
• 2021
  • 2021-10-26 WO PCT/NO2021/050222 patent/WO2022093035A1/en active Application Filing

Patent Citations (3)

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