GB2591070A

GB2591070A - Improvements in or relating to filtering apparatus

Info

Publication number: GB2591070A
Application number: GB1912530.1A
Authority: GB
Inventors: Kerr Gavin
Original assignee: Kerr - Mac Aquaculture Solutions Ltd; Kerr Mac Aquaculture Solutions Ltd
Current assignee: Kerr - Mac Aquaculture Solutions Ltd; Kerr Mac Aquaculture Solutions Ltd
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2021-07-21
Also published as: GB201912530D0; WO2021038179A1

Abstract

A filter apparatus for filtering parasites from water comprises a housing 2 with a water inlet (6, Fig. 1c) connected via a conduit 7 to a filter 8. The conduit has an air-lift pump or pressurised air injection port 17 and at least one pressurised air exit port 23 which are arranged such that, in use, when pressurised air is injected into the pressurised air injection port, a pressure differential is created in the conduit causing water to flow through the water inlet, conduit, and filter. The housing is preferably buoyant and at least partly submersible for use in a fish farm cage or other aquaculture enclosure.

Description

Improvements in or relating to filtering apparatus

Field of the invention

The present invention relates to a filter apparatus, and particularly, but not exclusively, a filter apparatus for filtering parasites, such as sea lice, from water. The present invention also relates to a method of filtering parasites from water and a filter system for filtering parasites from water.

Backaround to the invention

In fish farming, large populations of fish are held in net cages until they reach market weight and are ready for harvesting. The net cages keep the farmed fish contained but allow entry of parasites, which leads to parasite infestations and widespread disease in farmed fish. Parasite infestations and disease cause significant damage to farmed fish, resulting in unmarketable products and decreasing revenues for fish farms.

Typically, farmed fish are at risk of infections by a variety of parasites, such as sea lice, plankton, micro jellyfish, or nematodes. However, sea lice are highlighted as the most damaging parasite to both wild and farmed fish.

Sea lice are marine ectoparasites that have adapted to live on fish, typically salmon. They feed on the mucus, epidermal tissue and blood of the host fish to survive. The lice have a free-swimming juvenile phase where they need to find and attach to a host. Typically, when the juvenile sea lice reach approximately 1 mm in length, they can attach to a host fish. However, free-swimming juvenile sea lice will die if they cannot find a host fish to attach to and feed from.

Current methods used to control sea lice infestations in farmed fish focus on the removal of sea lice once they have attached to the fish. However, there are disadvantages with such known treatment methods.

For example, mechanical removal methods to detach sea lice from farmed fish are expensive and inefficient. Mechanical removal methods include, for example, spraying water at infected fish at an appropriate temperature and/or pressure to detach the sea lice from their host. Such methods can harm the welfare of the farmed fish, for example, by causing scale removal. Furthermore, mechanical methods are ineffective at removing all sea lice from the fish.

Chemical methods are also used as a common treatment for sea lice infestations on farmed fish. For example, harsh chemicals, such as hydrogen peroxide, may be administered to infected fish populations. The chemicals paralyse the sea lice, which causes them to fall off the host fish. However, chemical treatments have negative effects on the fish, causing a reduced appetite and preventing growth. Additionally, sea lice become resistant to chemical treatments and over time the efficiency of the treatment is reduced. Furthermore, adding large amounts of chemicals to fish farm cages could be damaging to the environment and negatively impact the ecology in surrounding waters.

The parasite control methods described above all target removal of sea lice after they are attached to fish. Therefore, the fish are already damaged when the sea lice are removed. In particular, wounds will be visible on the farmed fish where the sea lice have been removed. This reduces the market value of the resulting products. Consequently, there is a need to provide a method to remove or eradicate parasites from fish farms before they attach to the fish. In particular, methods of reducing the breeding population of sea lice in fish farms are desirable.

The inventor has appreciated the shortcomings in known parasite control methods.

Statements of Invention

According to a first aspect of the present invention there is provided a filter apparatus for filtering parasites from water comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected to the conduit; wherein the conduit comprises a pressurised air injection port and at least one pressurised air exit port, and wherein the pressurised air injection port, conduit and at least one pressurised air exit port are arranged such that, in use, when pressurised air is injected into the pressurised air injection port, a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.

The term "parasites" used throughout this specification is considered to include any organism that can live on or in an organism of another species, known as the host, and feed from said host.

The parasites may be ectoparasites. The parasites may be marine ectoparasites. The parasites may be sea lice, plankton, micro jellyfish, nematodes, or the like. The parasites may be sea lice. The parasites may be juvenile sea lice. The parasites may be free-swimming juvenile sea lice. That is, the parasites may not be attached to fish.

The water may be sea water. The water may be fresh water. The filter apparatus may be for filtering parasites from sea water. The filter apparatus may be for filtering parasites from fresh water.

The filter apparatus may be a water parasite filter apparatus. The filter apparatus may be a sea water parasite filter apparatus.

The filter apparatus may be configured to mitigate entry of fish into the apparatus.

The filter apparatus may be suitable for use in a volume of water. The 15 volume of water may be sea water or fresh water. The filter apparatus may be at least partially submersible in water. The filter apparatus may be at least partially submersible in sea water or fresh water.

The filter apparatus may be locatable in a fish cage on a fish farm. The filter apparatus may be locatable in a fish cage on a finfish farm. The filter apparatus may be locatable in a fish cage on a salmon farm. However, it should be appreciated that the fish farm could be any type of fish farm.

The housing may be configured such that it may float in water. The housing may be configured such that it may be at least partially submersible. In this arrangement, water may penetrate the housing. The water may penetrate the housing to a depth below the filter. The housing may be configured such that it remains upright when located in, or on, water.

The housing may be substantially conical. The housing may be substantially frustoconical. That is, the housing may be substantially in the shape of a truncated cone. The housing may be substantially pyramidal. The housing may be substantially frustopyramidal, or a truncated pyramid shape. The housing may have an inverted frustoconical shape. The housing may have an inverted frustopyramidal shape. The housing may have an inverted octagonal frustopyramidal shape.

The housing may have an upper end and a lower end. The upper end may be the base of the cone, or pyramid. The lower end may be the tip of the cone, or pyramid. The lower end may be the truncated tip of the cone, or pyramid. The area of the upper end may be greater than the area of the lower end. The upper end may be located distal to the water inlet. The lower end may comprise the water inlet.

The upper end may be substantially circular. The upper end may have a substantially square shape. The upper end may be substantially pentagonal. The upper end may be substantially hexagonal. The upper end may be substantially heptagonal. The upper end may be substantially octagonal. The upper end may be open. In such an arrangement, the upper end is open to the atmosphere.

The lower end may be a substantially planar member. The lower end may be substantially circular. The lower end may have a substantially square shape. The lower end may be substantially pentagonal. The lower end may be substantially hexagonal. The lower end may be substantially heptagonal. The lower end may be substantially octagonal. The lower end may be substantially closed.

The housing may comprise one or more wall portions. The housing may comprise one wall portion. In such an arrangement, the housing is an inverted conical, or inverted frustoconical shape. The housing may comprise four wall portions. In such an arrangement, the housing has an inverted truncated square pyramid shape. The housing may comprise five wall portions. In such an arrangement, the housing has an inverted truncated pentagonal pyramid shape. The housing may comprise six wall portions. In such an arrangement, the housing has an inverted truncated hexagonal pyramid shape. The housing may comprise seven wall portions. In such an arrangement, the housing has an inverted truncated heptagonal pyramid shape. The housing may comprise eight wall portions. In such an arrangement, the housing has an inverted truncated octagonal pyramid shape The, or each, wall portion may be a substantially planar member. The wall portions may be arranged in a tapered arrangement. The wall portions may converge downwards, such that the housing is narrower at the lower end than at the upper end. The separation between the wall portions may be greater at the upper end than at the lower end.

The, or each, wall portion may be substantially identical. The, or each, wall portion may be substantially trapezoidal. The, or each, wall portion may have an inverted trapezoid shape. The, or each wall portion, may have an upper portion and a lower portion. The width of the upper portion may be greater than the width of the lower portion. The lower portion may be located proximal to the water inlet. The upper portion may be located distal to the water inlet.

The, or each, wall portion may comprise at least one aperture.

Alternatively, one or more wall portions may have the aperture. The at least one aperture may be located between the upper portion and the lower portion of the, or each, wall portion. The at least one aperture may be located approximately in the middle of the upper portion and the lower portion of the, or each, wall portion. The at least one aperture may be approximately equidistant between the upper portion and the lower portion of the, or each, wall portion. The at least one aperture may be configured to allow water to enter and exit the housing. In such an arrangement, water is located on the inside and outside of the housing. The apertures may be provided to aid stabilisation of the housing when the wall portions are at least partially submerged in water. The apertures may be provided to allow the housing to be at least partially filled with water, such that, when the housing is at least partially submerged in water, the housing remains upright.

The lower end of the housing may be a base portion. The base portion may be connected to the lower portions of the wall portions of the housing.

The base portion may have a top surface and a bottom surface.

The base portion may comprise a plurality of apertures. The apertures may be located equidistantly around the centre of the base portion. The apertures may be arranged in a circular arrangement around the centre of the base portion. Each aperture may be located between the centre and edge of the base portion. The apertures may be configured to allow water to enter and exit the housing. In such an arrangement, water is located on the inside and outside of the housing. The apertures may be provided to aid stabilisation of the housing when the base portion is submerged in water. The apertures in the base portion may have a smaller diameter than the apertures in the wall portion.

The base portion may comprise the water inlet. The water inlet may be located in the base portion of the housing. The water inlet may be located approximately in the middle, or centre, of the base portion. The water inlet may be located approximately on, and in the middle of, the centre line, longitudinal axis, of the base portion. The water inlet may be located approximately in the middle of the apertures in the base portion. The water inlet may be an aperture.

The water inlet may be configured to be attachable to the conduit. The water inlet may be configured to be releasably attachable to the conduit.

In such an arrangement, the conduit may be removed, or detached, from the water inlet for cleaning.

The water inlet may be configured to mitigate entry of fish into the filter apparatus. The water inlet may be configured to mitigate entry of fish into the conduit. The water inlet may be substantially circular. The water inlet may have a diameter of less than 0.7 m. The water inlet may have a diameter of approximately 0.1 m. The water inlet may comprise an entry barrier member. The entry barrier member may be a physical barrier, such as a bar, mesh, grid, or the like.

The housing may be a substantially hollow member. The housing may house the conduit and the filter. The internal portion may be open. In such an arrangement, the internal portion is open to the atmosphere.

The housing may be made from plastic. The housing may be made from a thermoplastic. The housing may be made from acrylonitrile butadiene styrene.

The housing may comprise a parasite attractant. The base portion may comprise a parasite attractant. The bottom surface of the base portion may comprise a parasite attractant. The bottom surface of the base portion may comprise a sea lice attractant. The bottom surface of the base portion may comprise a juvenile sea lice attractant.

The parasite attractant may be located adjacent to the water inlet. The parasite attractant may be located on the bottom surface of the base portion, adjacent to the water inlet. The parasite attractant may be attachable to the top surface of the base portion, and may extend to the bottom surface of the base portion through an aperture.

The parasite attractant may be a light source. The light source may be any light source suitable for attracting parasites. The light source may be a blue light source. The light source may have a power of 133 Watts and a brightness of 800 lumens. The light source may be configured to attract parasites to the water inlet. The light source may be configured to attract sea lice to the water inlet. The light source may be configured to attract juvenile sea lice to the water inlet.

The light source may be remotely controlled. The light source may be controlled by a separate electrical box locatable within the fish farm cage. The electrical box may be connected to the light source by a water-resistant cable. The electrical box may be connected to the light source by a marine grade arctic flex cable.

The housing may comprise one or more buoyancy members. The, or each, buoyancy member may be attached to the housing. The, or each, buoyancy member may be arranged to allow the housing to float in water. 30 The, or each, buoyancy member may be located on the upper portion of the housing. The, or each, buoyancy member may be located on the outer perimeter of the upper portion of the housing. The, or each, buoyancy member may be a buoyancy ring. The, or each, buoyancy member may be a pipe, pipework, tube, or the like. The pipe may be enclosed. The pipe may be a closed pipe that is not open to the atmosphere. In such an arrangement, the pipe is empty. However, it should be appreciated that the pipe could be air-filled or filled with a material with a density less than water.

The, or each, buoyancy member may be made from plastic. The, or each, buoyancy member may be made from a thermoplastic. The, or each, buoyancy member may be made from polyethylene. The, or each, buoyancy member may be made from medium density polyethylene, high density polyethylene, or the like.

The housing may comprise at least one attachment point. The housing may comprise four attachment points. The housing may comprise one attachment point on alternate wall portions of the housing. The at least one attachment point may be located on the upper portion of the housing.

The at least one attachment point may be configured to be attachable to a tether, rope, anchor, or the like. The attachment point may be provided to secure the filter apparatus within the fish cage.

The conduit may be located in the housing. The conduit may be located on the inside of the housing.

The conduit may be removably attachable to the housing. The conduit may be removably attachable to the base portion of the housing. The conduit may be removably attachable to the water inlet.

The conduit may be configured to connect the water inlet to the filter. The conduit may be arranged to transport water from the water inlet to the filter.

The conduit may be substantially cylindrical. The conduit may have an outer wall portion. The conduit may be a pipe, pipework, or the like. The conduit may be a closed pipe. The pipe may be at least partially closed. The pipe may have an open section adjacent to the filter.

The conduit may be made from plastic. The conduit may be made from a thermoplastic. The conduit may be made from acrylonitrile butadiene styrene.

The conduit may have a first end and a second end. The first end may be located proximal to the water inlet. The first end may be located distal to the filter. The second end may be located distal to the water inlet. The second end may be located proximal to the filter.

The conduit may be configured to mitigate entry of fish into the apparatus. 20 The conduit may have a diameter of less than 0.7 m. The conduit may have a diameter of between approximately 0.1 and approximately 0.075 m. The diameter of the first end of the conduit may be greater than the diameter of the second end of the conduit. The first end of the conduit may have a diameter of approximately 0.1 m. The second end of the conduit may have a diameter of approximately 0.075 m. The conduit may comprise an entry barrier member. The entry barrier member may be a physical barrier, such as a bar, mesh, grid, or the like.

The conduit may comprise a vertical portion and at least one horizontal 30 portion.

The vertical portion may be located at the first end of the conduit. The vertical portion may be removably attachable to the base portion of the housing. The vertical portion may be removably attachable to the water inlet. The vertical portion may comprise the pressurised air injection port.

The conduit may comprise at least one horizontal portion. The at least one horizontal portion may be located at the second end of the conduit. The at least one horizontal portion may be connected to the vertical portion. The at least one horizontal portion may be connected to the top of the vertical portion. The at least one horizontal portion may be connected to the filter. The at least one horizontal portion may connect the top of the vertical portion to the filter. In such an arrangement, the conduit may be L-shaped.

The filter may be located at the end of the conduit. The filter may be located at the second end of the conduit. The filter may be located at the end of the horizontal portion of the conduit.

The end of the at least one horizontal portion may be an outlet of the conduit. The outlet of the conduit may be located at the second end of the conduit. The outlet of the conduit may be attachable to the filter. The outlet of the conduit may be a first water outlet. The outlet of the horizontal portion of the conduit may be a first water outlet. The outlet of the conduit may be a parasite-containing water outlet.

The filter may be connected to the outlet of the conduit. The filter may be connected to the horizontal portion of the conduit.

The filter may be located inside the housing. The filter may be located adjacent to the wall portion of the housing. The filter may be located adjacent to the internal wall portion of the housing.

The filter may be located in the conduit.

The filter may be configured to filter parasites from water. The filter may be configured to filter free-swimming juvenile sea lice from sea water.

The filter may comprise a filter mount. The filter mount may be configured to secure the filter to the housing. The filter mount may be arranged to direct the flow of water from the conduit through the filter. The filter mount may funnel the water into the filter.

The filter mount may be substantially semi-cylindrical. The filter mount may have a first end and a second end. The first end of the filter mount may be connected to the outlet of the conduit. The first end of the filter mount may be a filter inlet. The first end of the filter mount may have an open part, the open part of the first end of the filter mount defining the filter inlet. The first end of the filter mount may have a closed part. The closed part may be located proximal to the filter inlet. The second end of the filter mount may be a filter outlet. The filter outlet may be configured to release parasite-free water. The filter outlet may be configured to release parasite-free water to the inside of the housing. In such an arrangement, the parasite-free water can exit the housing through the apertures in the wall portions and the base portion. The filter outlet may be configured to release parasite-free water to the outside of the housing. In such an arrangement, the parasite-free water can exit the housing through the apertures in the wall portions behind the filter mount.

The filter outlet may be a second water outlet. The filter outlet may be a parasite-free water outlet.

The filter may comprise one or more filter cartridges. The filter mount may comprise one or more filter cartridges. The filter may comprise two filter cartridges. The, or each, filter cartridge may be located inside the filter mount. The, or each, filter cartridge may be removable. The filter mount may be configured to receive one or more cartridges.

The filter may be a single stage filter. In such an arrangement, the filter comprises one filter cartridge. The filter may be a two-stage filter. In such an arrangement, the filter comprises two filter cartridges. The filter may be a multi-stage filter. In such an arrangement, the filter comprises two or more filter cartridges.

The one or more filter cartridges may be substantially cylindrical. The one or more filter cartridges may be substantially cylindrical mesh filter cartridges. The mesh filter cartridges may be made from metal. The mesh filter cartridges may be made from nylon. The mesh filter cartridges may zo be made from stainless steel.

The one or more filter cartridges may be removably attachable to the filter mount. In such an arrangement, the one or more filter cartridges may be removed for cleaning or replacement when they become blocked or 25 damaged.

The filter mount may comprise a first filter cartridge and a second filter cartridge. The first filter cartridge may be located inside the second filter cartridge. The first filter cartridge may have a mesh size greater than the second filter cartridge. The first filter cartridge may have a mesh size of approximately 800 pm. However, other filter sizes may be used. The second filter cartridge may be located between the first filter cartridge and the filter mount. The second filter cartridge may be configured to receive the first filter cartridge. The second filter cartridge may configured to filter parasites smaller in size than the first filter cartridge. The second filter cartridge may have a mesh size smaller than the first filter cartridge. The second filter cartridge may be configured to filter parasites less than 800 pm. The second filter cartridge may have a mesh size of approximately 150 pm. However, other filter sizes may be used.

The filter may comprise a lid. The filter mount may comprise a lid. The lid may form the closed part of the first end of the filter mount. The lid may be detachably removable from the filter. The lid may include a seal, such that the lid is in a sealed engagement with the filter mount. The lid may comprise locking means, such that, in use, when the lid is closed over the filter mount, the lid is locked, or secured, in place. The filter mount and the lid may be configured to allow access to the inside of the filter chamber when the lid is removed.

The housing may comprise at least one water outlet. The at least one water outlet may be located inside the housing. The at least one water outlet may be located on the wall portion of the housing. The at least one water outlet may be located distal to the water inlet.

The housing may comprise a first water outlet and a second water outlet. The first water outlet may be the outlet of the conduit. The first water outlet may be configured to release parasite-containing water. The second water outlet may be the filter outlet. The second water outlet may be located on the internal wall portion of the housing. The second water outlet may be configured to release parasite-free water into the inside of the housing.

The at least one pressurised air injection port may be located in the vertical portion of the conduit. The at least one pressurised air injection port may be located in the lower part of the vertical portion of the conduit. The at least one pressurised air injection port may be located proximal to the water inlet.

The at least one pressurised air injection port may be configured to receive a source of compressed air. The at least one pressurised air injection port may be connectable to a source of compressed air.

However, it should be appreciated that other compressed gases or fluids may be used to create the pressure differential in the conduit.

The pressurised air injection port may comprise a coupling member. The coupling member may be located on the conduit. The coupling member may be located on the lower part of the vertical portion of the conduit. The coupling member may be located on at least part of the lower part of the vertical portion of the conduit.

The coupling member may be an annular cuff. The coupling member may surround at least a part of the vertical portion of the conduit. The coupling member may have an inner wall. The coupling member may be configured to provide a gap between the inner wall of the coupling member and the outer wall of the conduit. The gap may be annular, at least partially annular, toroidal, or at least partially toroidal. The gap may be an at least partial toroidal gap. The gap may define a volume that receives the pressurised air before it enters the conduit. The gap may be between approximately 3 and approximately 10 mm. The gap may be between approximately 5 and approximately 7 mm.

The pressurised air injection port may comprise a first air inlet. The first air inlet may be located on the coupling member. The first air inlet may be attachable to a source of compressed air. The first air inlet may have a connection member. The connection member may be a threaded connection member. The connection member may be a spigot connector.

The outer wall portion of the conduit may include a plurality of pressurised air inlets. The plurality of pressurised air inlets may be apertures. The apertures may be located on the part of the vertical portion of the conduit surrounded by the coupling member. The apertures may be located on the conduit, adjacent to the gap between the inner wall of the coupling member and the outer wall of the conduit. The apertures may be arranged around the conduit. The apertures may have a diameter of approximately 1 mm. In this arrangement, the annular cuff allows pressurised air to enter (and fill) the gap between the outer wall of the conduit and the inner wall of the cuff. The pressurised air then enters the conduit via the apertures.

The pressurised air injection port may comprise a sealed connection between the outer edge of the coupling member and the conduit, such that, in use, pressurised air from the compressed air source fills the gap and enters the conduit through the plurality of apertures.

The pressurised air injection port may be arranged such that, in use, when pressurised air is injected into the first air inlet, pressurised air fills the gap and enters the conduit though the plurality of apertures. In such an arrangement, the pressurised air disperses, or fragments, before it enters the conduit, which results in a consistent, even stream of air entering the conduit. This allows the flow rate of water through the conduit to remain consistent and controlled.

The at least one pressurised air exit port may be located in the horizontal portion of the conduit. The at least one pressurised air exit pod may be directed upwards. The at least one pressurised air exit port may be located at the opposite side of the horizontal portion of the conduit to the side of the horizontal portion that is adjacent to vertical portion of the conduit. The at least one pressurised air exit port may be located on the opposite side of the horizontal portion to the side of the horizontal portion that connects to the top of the vertical portion of the conduit.

The at least one pressurised air exit port may be substantially upright. The at least one pressurised air exit port may be substantially perpendicular to the horizontal portion of the conduit. The at least one pressurised air exit port may be located between the water inlet and the filter. The at least one pressurised air exit port may be located between the pressurised air injection port and the filter.

The at least one pressurised air exit port may be open to the atmosphere. The at least one pressurised air exit port may be an air outlet.

The pressure differential may be created in the conduit between the water inlet and the outlet of the conduit. The pressure in the conduit at the water inlet may be greater than the pressure in the conduit at the outlet of the conduit. The pressure at the pressurised air injection port may be greater than the pressure at the pressurised air exit ports.

The pressure differential may cause water to flow through the water inlet, through the conduit, to the filter. The pressure differential may cause water to flow through the water inlet, through the conduit, to the outlet of the conduit.

The flow rate of the water in the conduit may be approximately 0.015 to 5 0.020 m3/s. The flow rate of water in the conduit may be approximately 0.017 m3/s.

The filter apparatus may further comprise a source of compressed air. The source of compressed air may be configured to provide pressurised air to the apparatus.

The conduit may comprise at least two or more horizontal portions. The two or more horizontal portions may be branched. Each horizontal portion may be connected to the top of the vertical portion of the conduit. Each horizontal portion may be connected to a filter. The end of each horizontal portion of the conduit may be an outlet of the conduit.

The conduit may comprise two horizontal portions. In such an arrangement, the conduit is in a substantially T-shaped arrangement The conduit may comprise three horizontal portions. The conduit may comprise four horizontal portions. In such an arrangement, the horizontal portions are in the shape of a cross. That is, the horizontal portions may cross at an intersection located at the top of the vertical portion.

The housing may comprise two or more filters. The housing may comprise two filters. The housing may comprise a filter at the end of each horizontal portion of the conduit. The housing may comprise a filter at each outlet of the conduit.

The conduit may comprise two or more pressurised air exit ports. The conduit may comprise four pressurised air exit ports. The conduit may comprise six air exit ports. The conduit may comprise eight pressurised air exit ports. Each horizontal portion may comprise at least one pressurised air exit port. Each horizontal portion may comprise two pressurised air exit ports.

According to a second aspect of the present invention there is provided a method of filtering parasites from water, the method comprising the steps 10 of: providing a filter apparatus for filtering parasites from water comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected the conduit; wherein the conduit comprises a pressurised air injection port and at least one pressurised air exit port; connecting the pressurised air injection port to a source of compressed air; and injecting compressed air into the pressurised air injection port, such that a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.

The method may comprise the further step of releasing the filtered water into the housing. The filtered water may be parasite-free water. It should be appreciated that the filtered water is released into the inside of the housing. That is, the filtered water is released back to the original water source that flows through the water inlet. In such an arrangement, the filter apparatus is provided to reduce the breeding population of parasites in fish farms.

Embodiments of the second aspect of the present invention may include one or more features of the first aspect of the present invention or its embodiments. Similarly, embodiments of the first aspect of the present invention may include one or more features of the second aspect of the present invention or its embodiments.

According to a third aspect of the present invention there is provided a filter system for filtering parasites from water, the system comprising two or more filter apparatus, each filter apparatus comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected to the conduit; wherein the conduit comprises a pressurised air injection port and at least one pressurised air exit port, and wherein the pressurised air injection port, conduit and at least one pressurised air exit port are arranged such that, in use, when pressurised air is injected into the pressurised air injection port, a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.

The filter system may further comprise a source of compressed air. The source of compressed air may be configured to provide pressurised air to each apparatus.

Embodiments of the third aspect of the present invention may include one or more features of the first or second aspects of the present invention or their embodiments. Similarly, embodiments of the first or second aspects of the present invention may include one or more features of the third aspect of the present invention or its embodiments.

According to a fourth aspect of the present invention there is provided a method of operating a filter system for filtering parasites from water, the method comprising the steps of: providing two or more filter apparatus, each filter apparatus comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected to the conduit; wherein the conduit comprises a pressurised air injection port and at least one pressurised air exit port, and connecting the pressurised air injection port of each apparatus to a source of compressed air; and injecting compressed air into the pressurised air injection port of each apparatus, such that a pressure differential is created in the conduit 20 of each apparatus, which causes water to flow through the water inlet, conduit, and the filter.

Embodiments of the fourth aspect of the present invention may include one or more features of the first, second or third aspects of the present invention or their embodiments. Similarly, embodiments of the first, second or third aspects of the present invention may include one or more features of the fourth aspect of the present invention or its embodiments.

According to a fifth aspect of the present invention there is provided a filter apparatus for filtering parasites from water comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected to the conduit; wherein the conduit is configured to be attachable to suction means such that, in use, when suction means are attached to the conduit, a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.

The suction means may be located distal to the water inlet. The suction means may be located at the second end of the conduit. The suction means may be located at the top of the vertical portion of the conduit. The suction means may be located on the at least one horizontal portion of the conduit. The suction means may be located on the opposite side of the horizontal portion of the conduit to the side of the horizontal portion that connects to the top of the vertical portion of the conduit.

The suction means may be configured to draw, or pull, water through the water inlet and the conduit.

The suction means may be any suction device or machine.

Embodiments of the fifth aspect of the present invention may include one or more features of the first, second, third or fourth aspects of the present invention or their embodiments. Similarly, embodiments of the first, second, third or fourth aspects of the present invention may include one or more features of the fifth aspect of the present invention or its embodiments.

According to a sixth aspect of the present invention there is provided a method of filtering parasites from water, the method comprising the steps of: providing a filter apparatus for filtering parasites from water comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; and a filter connected to the conduit; and connecting the conduit to suction means, such that a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.

The method may comprise the further step of releasing the filtered water into the housing. The filtered water may be parasite-free water. It should be appreciated that the filtered water is released into the inside of the housing. That is, the filtered water is released back to the original water source that flows through the water inlet. In such an arrangement, the filter apparatus is provided to reduce the breeding population of parasites zo in fish farms.

Embodiments of the sixth aspect of the present invention may include one or more features of the first, second, third, fourth or fifth aspects of the present invention or their embodiments. Similarly, embodiments of the first, second, third, fourth or fifth aspects of the present invention may include one or more features of the sixth aspect of the present invention or its embodiments.

According to a seventh aspect of the present invention there is provided a filter system for filtering parasites from water, the system comprising two or more filter apparatus, each filter apparatus comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; and a filter connected to the conduit; wherein the conduit is configured to be attachable to suction means such that, in use, when suction means are attached to the conduit, a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.

The system may further comprise suction means. The suction means may be configured to create a pressure differential in the conduit of each 15 apparatus.

Embodiments of the seventh aspect of the present invention may include one or more features of the first, second, third, fourth, fifth, or sixth aspects of the present invention or their embodiments. Similarly, embodiments of the first, second, third, fourth, fifth or sixth aspects of the present invention may include one or more features of the seventh aspect of the present invention or its embodiments.

According to an eighth aspect of the present invention there is provided a method of operating a system for filtering parasites from water, the method comprising the steps of: providing two or more filter apparatus, each filter apparatus comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; and a filter connected to the conduit; wherein the conduit is configured to be attachable to suction means; and attaching suction means to the conduit of each apparatus, such that a pressure differential is created in the conduit of each apparatus, which causes water to flow through the water inlet, conduit, and the filter.

Embodiments of the eighth aspect of the present invention may include one or more features of the first, second, third, fourth, fifth, sixth or seventh aspects of the present invention or their embodiments. Similarly, embodiments of the first, second, third, fourth, fifth, sixth or seventh aspects of the present invention may include one or more features of the seventh aspect of the present invention or its embodiments.

Brief description of the drawings

Embodiments of the invention will now be described, by way of example only, with reference to the drawings, in which: Fig. la is an isometric view of a filter apparatus according to an aspect of the present invention; Fig lb is a top view the filter apparatus of Fig. la; Fig. lc is a bottom view the filter apparatus of Fig. la; Fig ld is a front view the filter apparatus of Fig. la; Fig 1e is a side view the filter apparatus of Fig. 1 a; Fig if is a back view the filter apparatus of Fig. I a; Fig 2 is an isolated, outline, front view of the conduit of a filter apparatus of Figs. la to if; Fig. 3a is an isolated, exploded view of the pressurised air injection port on the conduit of the filter apparatus of Figs. la to 1f; and Fig. 3b is a partial cut away view of the coupling member on the pressurised air injection port of Fig. 3a.

Description of preferred embodiments

Figs. la to if illustrate a filter apparatus 1 for filtering parasites from water. In the embodiment illustrated and described here, the filter apparatus 1 is suitable for filtering juvenile sea lice from water. However, it should be appreciated that the filter apparatus 1 may be suitable for filtering other parasites that are not already attached to fish, such as sea lice nematodes, plankton, or micro jellyfish from water. Targeting the removal of parasites, such as free-swimming juvenile sea lice, from water before they attach to fish is advantageous because it prevents damage to the fish caused by the sea lice, or other parasites, and avoids the need for parasite removal methods that require interaction with the fish. This increases the market value of the resulting products, which increases revenues for fish farms. Furthermore, targeting the removal of juvenile sea lice from the fish farm cages reduces the breeding population of sea lice within the cages, which can prevent sea lice infestations by reducing the number of sea lice that are able to attach to fish.

The filter apparatus 1 is locatable in a fish cage on a fish farm. Generally, the filter apparatus 1 is locatable in a fish cage on salmon farms.

However, it should be appreciated that the filter apparatus 1 may be used on any type of fish farms where parasites are a problem.

The filter apparatus 1 includes a housing 2, the housing 2 being configured so that it floats in water during use. In use, the housing 2 is lowered into a fish cage on a fish farm and is partially submerged in the water. In this arrangement, water enters the inside of the housing 2.

In the embodiment illustrated and described here, the housing 2 has an inverted octagonal frustopyramidal shape. However, it should be appreciated that the housing 2 may have a generally frustoconical or frustopyramidal shape, or any other suitable shape.

The housing 2 has an upper end 2a and a lower end, or base portion 2b.

As shown in Fig. la, the upper end 2a is the base of the pyramid and the base portion 2b is the truncated tip of the pyramid. In the embodiment illustrated and described here, and as best shown in Fig. la, the upper end 2a is octagonal. However, it should be appreciated that the upper end 2a may be substantially circular, square, or another shape depending on the overall shape of the housing 2. When the housing 2 is partially submerged in water, the upper end 2a is open to the atmosphere.

The base portion 2b is a substantially planar member. In the embodiment illustrated and described here, and as best shown in Fig. 1 c, the base portion 2b is octagonal. However, it should be appreciated that the base portion 2b may be substantially circular, square, or another shape depending on the overall shape of the housing 2.

In the embodiment illustrated and described here, the housing 2 has eight wall portions 3. However, it should be appreciated that the housing 2 may have one wall portion 3 Cif conical), or four or more wall portions 3 (if pyramidal).

The wall portions 3 are substantially planar members. As shown in Figs. la to if, the wall portions 3 are arranged in a tapered arrangement. That is, the wall portions 3 converge downwards, such that the housing 2 is narrower at the lower end 2b than at the upper end 2a.

As shown best in Fig. 10, the wall portions 3 are substantially identical planar trapezoids. As shown in Fig. la, each wall portion 3 has an upper portion 3a and a lower portion 3b. The width of the upper portion 3a is greater than the width of the lower portion 3b. In this embodiment, the width of the upper portion 3a is 930 mm and the width of the lower portion 3b is 330 mm. Additionally, in this embodiment the length of each wall portion 3 from the centre of the lower portion 3b to the centre of the upper portion 3a is 1570 mm, and the length of the lateral side (from the edge of the lower portion 3b to the edge of the upper portion 3a) of each wall portion 3 is 1480 mm. However, it should be understood that alternative dimensions may be used.

As shown in Figs. la to if, each wall portion 3 comprises an aperture 4. However, it should be appreciated that there may not be an aperture 4 in each wall portion 3. The aperture 4 is located approximately in the middle of the upper portion 3a and the lower portion 3b of each wall portion 3. In this embodiment, the apertures 4 have a diameter of 330 mm. However, it should be understood that alternative dimensions may be used. In use, when the apparatus 1 is partially submerged in water, the apertures 4 allow water to enter and exit the housing 2. This allows the housing 2 to be at least partially filled with water, which aids in keeping the housing 2 upright. The apertures 4 also aid stabilisation of the housing 2 by allowing water to pass through the housing 2, thereby reducing the impact of waves or other disturbances in the water on the outside of the housing 2. Furthermore, the apertures 4 allow both parasites and fish to enter and exit the housing 2.

As shown best in Fig. lc, the base portion 2b is connected to the lower portions 3b of the wall portions 3 of the housing 2. The base portion has a top surface 2c and a bottom surface 2d.

As shown in Figs. lb and 1 c, the base portion 2b comprises a plurality of apertures 5. The apertures 5 are arranged in a circular arrangement around the centre of the base portion 2b. In this embodiment, the apertures have a diameter of 100 mm. However, it should be understood that alternative dimensions may be used. In use, when the apparatus 1 is partially submerged in water, the apertures 5 allow water to enter and exit the housing 2. This allows the housing 2 to be at least partially filled with water, which aids in keeping the housing 2 upright. The apertures 5 also aid stabilisation of the housing 2 by allowing water to enter and exit the housing 2. Furthermore, the apertures 5 allow both parasites and fish to enter and exit the housing 2. When the apparatus 1 is partially submerged in water, the base portion 2b and the apertures Swill be fully submerged in the water.

As shown best in Fig. lc, the base portion 2b comprises a water inlet 6.

The water inlet 6 is located in the centre of the base portion 2b. However, it should be appreciated that the water inlet 6 may be located anywhere on the base portion 2b, or elsewhere on the housing provided it is submerged in the water containing the parasites to be filtered. In the embodiment described and illustrated here, the water inlet 6 is an aperture.

The water inlet 6 is configured to be releasably attachable to a conduit 7. In the embodiment described and illustrated here, the water inlet 6 is an aperture comprising a union fitting configured to attach to the conduit 7. However, it should be appreciated that the union fitting may be any threaded fitting that can connect the conduit 7 to the water inlet 6. In use, the conduit 7 may have a threaded connector that can be screwed into the water inlet 6 in the base portion 2b. This allows the conduit 7 to be detached from the water inlet 6 for cleaning or removal of any debris in the inlet 6.

In this embodiment, the water inlet 6 has a diameter of approximately 100 mm. This diameter is suitable to prevent entry of fish into the conduit 7. As such, the water inlet 6 is configured to mitigate entry of fish into the filter apparatus 1. Alternatively, or additionally, an entry barrier member may be used to prevent fish entering the water inlet 6. The entry barrier member may be any physical barrier, such as a bar, mesh, grid, or the like.

As shown in Fig. la, the housing 2 houses the conduit 7 and at least one filter 8. The internal portion of the housing 2 is open to the atmosphere.

In the embodiment illustrated and described here, the housing 2 is made from acrylonitrile butadiene styrene. However, it should be appreciated that the housing 2 may be made from other suitable materials, such as other plastics materials.

The base portion 2b comprises a parasite attractant 10. As shown best in Figs. lb and lc, the parasite attractant 10 is attachable to the top surface 2c of the base portion 2b and extends to the bottom surface 2d of the base portion 2b through an aperture 11. However, it should be appreciated that the parasite attractant 10 may be located anywhere on the base portion proximal to the water inlet 6. In this embodiment, the parasite attractant 10 is a light source 10 that is attached by a 326 stainless steel bracket to the base portion 2b. However, it should be appreciated that the light source 10 may be attached to the base portion 2b by other suitable means In this embodiment, the light source 10 is blue light source with a power of 133 Watts and a brightness of 800 lumens. However, it should be appreciated that other light sources suitable for attracting parasites to the water inlet 6 may be used. In use, when the light source 10 is switched on by the user, the parasites are attracted towards the light. This allows a greater number of parasites to be drawn into the water inlet 6 when the filter apparatus 1 is in use. In this embodiment, the light source 10 is controlled by a separate Grp electrical box located within the fish farm cage. The electrical control box is connected to the light source 10 by a water-resistant cable 12. In this embodiment, the water-resistant cable 12 is a marine grade arctic flex cable. However, it should be understood that any water-resistant cable 12 may be used.

As shown in Figs. la to 1f, the housing 2 comprises a buoyancy member 13. In use, the buoyancy member 13 aids the housing 2 to float in the water. That is, the housing 2 will be submerged in water up to the level of zo the buoyancy member 13. The buoyancy member 13 is located on the outer perimeter of the upper portion 3a of the wall portion 3 of the housing 2. In this embodiment, the buoyancy member 13 is a buoyancy ring 13 made from pipework, such as Fusion pipework, and is fixed to the housing 2 with brackets 9. In this embodiment, the brackets 9 are 316 grade stainless steel brackets. However, it should be understood that any brackets, or fittings 9 may be used to attach the buoyancy member 13 to the housing 2. It should also be appreciated that the buoyancy ring 13 may be made from any pipe, pipework, tube, or the like. In this arrangement, the pipe 13 is closed to the atmosphere and is configured to float on water.

In the embodiment illustrated and described here, the buoyancy member 13 is made from medium or high density polyethlyene. However, it should be appreciated that the buoyancy member 13 may be made from other suitable materials, such as other plastics materials.

As shown best in Figs. la and 1 b, the housing 2 comprises four attachment points 14. However, it should be appreciated that a different number of attachment points 14 may be used. In this embodiment, the housing 2 comprises one attachment point 14 on alternate wall portions 3 of the housing 2. In use, the attachment points 14 can be attached to a tether, rope, anchor, or the like. This allows the filter apparatus 1 to be secured in a specific location within the fish cage.

As shown in Fig. 1 a, the conduit 7 is located in the housing. The conduit 7 connects the water inlet 6 to the filter 8. That is, the conduit 7 is arranged to transport water from the water inlet 6 to the filter 8. The water transported to the filter will comprise parasites, but the fish are prevented from entering the conduit 7. The fish are prevented from entering the conduit 7 due to the diameter of the conduit 7 and/or the provision of an entry barrier member as described below.

The conduit 7 is substantially cylindrical. The conduit 7 has an outer wall portion 7a. In this embodiment, the conduit 7 is a pipe, pipework, or the like.

In the embodiment illustrated and described here, the conduit 7 is made from acrylonitrile butadiene styrene. However, it should be appreciated that the conduit 7 may be made from other suitable materials, such as other plastics materials.

As shown best in Fig. 2, the conduit 7 has a first end 7b and a second end 7c. The first end 7b is located proximal to the water inlet 6 and distal to the filter 8. The second end 7c is located distal to the water inlet 6 and proximal to the filter 8.

In this embodiment, the first end of the conduit 7b has a diameter of approximately 100 mm, which prevents fish from entering the conduit 7. That is, the conduit 7 is configured to mitigate entry of fish into the filter apparatus 1. Alternatively, or additionally, an entry barrier member (not shown) may be used to prevent fish entering the conduit 7. The entry barrier member may be any physical barrier, such as a bar, mesh, grid, or the like.

The diameter of first end of the conduit 7b is greater than the diameter of the second end of the conduit 7c. In this embodiment, the second end of the conduit 7c has a diameter of approximately 75 mm. However, it should be appreciated that other dimensions may be used.

As shown in Fig. 2, the conduit 7 comprises a vertical portion 15 and at least one horizontal portion 16. In this embodiment, the conduit 7 has two horizontal portions 16. Each horizontal portion 16 includes a filter 8 located at the end thereof In this arrangement, the conduit 7 is substantially T-shaped. However, it should be appreciated that one or more than two horizontal portions 16 may be used.

The vertical portion 15 is located at the first end 7b of the conduit 7. The vertical portion 15 is removably attachable to the base portion 2b of the housing 2. Therefore, the conduit 7 can be removed for cleaning or replacement if it is damaged. The vertical portion 15 comprises the pressurised air injection port 17.

The horizontal portions 16 are located at the second end 7c of the conduit 7. In this embodiment, each horizontal portion 16 is connected from the top of the vertical portion 15 to a filter 8. One filter 8 is located at the end of each horizontal portion 16 of the conduit 7.

The end of each horizontal portion 16 is an outlet 18 of the conduit 7. The outlet 18 of the conduit 7 is a first water outlet 18. As described further below, the first water outlet 18 releases parasite-containing water into the filter 8.

As shown in Fig. la, the filter 8 is connected to the outlet 18 of the conduit 7. In this embodiment, the housing 2 comprises two filters 8. However, it should be appreciated that more than two filters 8 may be used.

As shown best in Fig. la, each filter 8 comprises a filter mount 8a. The filter mount 8a is configured to secure the filter 8 to the housing 2. That is, it is used to fix the filter 8 to the side of the housing 2. In use, the filter mount 8a directs the flow of water from the conduit 7 through the filter 8. That is, the water that exits the conduit 7 must flow through the filter 8 before it is returned to the surrounding water in the fish cage.

The filter mount 8a is substantially semi-cylindrical. The filter mount 8a has a first end 8b and a second end 8c. The first end 8b is connected to the outlet 18 of the conduit 7. This allows the parasite containing water to enter the filter 8. The first end 8b has an open part, or filter inlet that is located at the outlet 18 of the conduit 7. The first end 8b also has a closed part, or lid 19. The second end 8c of the filter mount 8b is a filter outlet 8c.

In this embodiment, the filter outlet 8c is the aperture 4 in the wall portion 3. This allows parasite-free water to exit the housing 2 through the apertures 4 in the wall portions 3. That is, the parasite-free water is released back into the water that the parasites were initially removed from.

This is beneficial as over time the overall population of parasites in the water will be reduced. However, it should be understood that the filter outlet Sc may also be at the bottom of the filter mount 8a. In such an arrangement, the parasite-free water is released into the inside of the housing and can exit the housing through the apertures 4, 5 in the wall portions 3 and the base portion 2b.

The filter outlet 8c is a second water outlet 8c, or parasite-free water outlet.

The filter mount 8a comprises one or more filter cartridges 20 (partially shown in Fig. la). In this embodiment, the filter 8 comprises two filter cartridges 20 located inside the filter mount 8a. However, it should be appreciated that a different number of filter cartridges 20 may be used. The filter cartridges 20 are removable. This is advantageous as they can be removed for cleaning if they become blocked and they can also be easily replaced or repaired if they become damaged.

In this embodiment, the filter 8 is a two-stage filter. That is, the filter 8 comprises two filter cartridges 20. However, it should be appreciated that a different number of filter cartridges 20 may be used.

The filter cartridges 20 are substantially cylindrical mesh filter cartridges. In this embodiment, the filter cartridges 20 are made from stainless steel metal mesh. However, it should be appreciated that the filter cartridges 20 30 may be made from other suitable materials, such as nylon mesh.

In this embodiment, the filter mount 8a comprises a first filter cartridge 20a and a second filter cartridge 20b (not shown). The first filter cartridge 20a is located inside the second filter cartridge 20b. The first filter cartridge 20a has a mesh size greater than the second filter cartridge 20b. That is, the first filter cartridge 20a is course and the second filter cartridge 20b is fine. In this embodiment, the first filter cartridge 20a has a mesh size of approximately 800 pm. However, it should be understood that other filter sizes may be used. This is used to remove larger parasites or debris before they reach the second filter cartridge 20b. This prevents the second filter cartridge 20b from getting blocked too quickly, which reduces the frequency of filter cartridge 20 cleaning and/or replacement and improves the efficiency of the filter 8. The second filter cartridge 20b is located between the first filter cartridge 20a and the filter mount 8a. The second filter cartridge 20b is configured to filter parasites smaller in size than the first filter cartridge 20a. In this embodiment, the second filter cartridge 20b has a mesh size of approximately 150 pm. However, it should be appreciated that other filter sizes may be used. By using a second filter cartridge 20b with a smaller mesh size, other smaller parasites, such as plankton, can be removed from the fish cages in addition to the sea lice. This is of great benefit to fish farms as it can remove more than one type of parasite from the fish cages using a single method.

The lid 19 is detachably removable from the filter. As shown in Fig. la, the lid 19 includes a seal 19a, such that the lid 19 is in a sealed engagement with the filter mount 8a. The lid 19 comprises locking means 21, such that, in use, when the lid 19 is closed over the filter mount 8a, the lid 19 is locked, or secured, in place. In this embodiment, the locking means 21 are adjustable locking brackets. However, any suitable locking means may be used. This prevents any water from the outlet 18 of the conduit 7 being released out of the top of the filter 8, but still allows access to the inside of the filter chamber 20 when the lid 19 is removed. The lid 19 is attached to the housing 2 by a hinge 22, which allows the lid 19 to be opened and closed. In this embodiment, the lid 19 is attached to the housing 2 by 316 stainless steel hinges 22. However, it should be understood than any suitable hinge may be used.

As shown best in Fig. 2, the conduit 7 comprises a pressurised air injection port 17 and a plurality of pressurised air exit pods 23. As shown in Fig. 2, the pressurised air injection port 17 is located in the lower part of the vertical portion 15 of the conduit 7. However, it should be appreciated that the pressurised air injection port 17 may be located anywhere on the conduit 7 before the pressurised air exit pods 23.

The pressurised air injection port 17 is connectable to a source of compressed air (not shown). However, it should be appreciated that other compressed gases or fluids may be attached to the pressurised air injection port 17. In use, a source of compressed air is attached by the zo user to a first air inlet 24. The first air inlet 24 has a threaded connection that is compatible with the outlet for the source of compressed air. In this embodiment, the connection on the first air inlet 24 is a spigot connector. However, it should be appreciated that other suitable connection members may be used. There is normally a source of compressed air located on fish farms, which means that the apparatus 1 can easily be integrated into existing fish farms without the need for additional machinery or equipment. However, it should be understood that the apparatus 1 may also comprise a source of compressed air.

As shown in Figs. 2 and 3a, the pressurised air injection port 17 comprises a coupling member 25. The coupling member 25 is located on the lower part of the vertical portion 15 of the conduit 7. In this embodiment, the coupling member 25 is located 260 mm from the base portion 2b.

However, it should be appreciated that the coupling member 25 may be located anywhere on the conduit 7 before the pressurised air exit ports 23.

In the embodiment described and illustrated here, the coupling member 25 is an annular cuff, which surrounds at least a portion of the vertical portion 15 of the conduit 7. As shown in Fig. 3b, the coupling member 25 has an inner wall 26. The coupling member 25 is configured to provide a gap 27 between the inner wall 26 of the coupling member 25 and the outer wall 7a of the conduit 7. The gap 27 defines a volume that receives the pressurised air before it enters the conduit 7. In this embodiment, the gap 27 is between approximately 5 and approximately 7 mm. However, it should be appreciated that other dimensions may be used. In this embodiment, the gap 27 is an at least partial toroidal gap.

As shown in Fig. 3b, the outer wall 7a of the conduit 7 includes a plurality of pressurised air inlets 28. The plurality of pressurised air inlets 28 are apertures 28 located on the part of the vertical portion 15 of the conduit 7 surrounded by the coupling member 25. That is, the apertures 28 are only present on the conduit 7 behind the coupling member 25. The apertures 28 are arranged around the conduit. However, it should be appreciated that the aperture 28 may be arranged in any configuration around the conduit 7. In this embodiment, the apertures 28 have a diameter of approximately 1 mm. However, it should be appreciated that other dimensions may be used.

As shown best in Figs. 3a and 3b, the pressurised air injection port 17 comprises a sealed connection between the outer edge 25a of the coupling member 25 and the conduit 7. Therefore, when pressurised air is injected into the first air inlet 24, it cannot escape out from behind the coupling member 25. This allows pressurised air from the compressed air source to fill the gap 27 and enter the conduit 7 through the plurality of apertures 28.

In use, when pressurised air is injected into the first air inlet 24, pressurised air fills the gap 27 and enters the conduit 7 through the plurality of apertures 28. In such an arrangement, the pressurised air disperses, or fragments, before it enters the conduit 7, which results in a consistent, even stream of air entering the conduit 7. This allows the flow rate of water through the conduit 7 to remain consistent and controlled. If the flow of air is not controlled, this can lead to blockages in the filters 8 and reduces the efficiency of the filter apparatus 1.

The injection of air into the pressurised air injection port 17 creates a pressure differential in the conduit 7 between the water inlet 6 and the outlet 18 of the conduit 7. That is, the pressure at the pressurised air injection port 17 is greater than the pressure at the outlet 18 of the conduit 7 because the pressurised air exit ports 23 expel the pressurised air as it passes through the conduit 7. This pressure differential causes water to be drawn, or sucked, into the water inlet 6 and flow through the conduit 7 to reach the filter 8.

In this embodiment, the flow rate of the water in the conduit 7 is approximately 0.017 m3/s. However, it should be appreciated that the flow rate can be changed to provide a flow of water suitable for the user and/or depending on the parasites to be filtered.

The use of compressed air to create a pressure differential in the conduit 7 is preferred because the energy required to operate a compressed air source is much lower than the energy required to operate suction means to pull the water through the conduit, which reduces running costs of the apparatus 1.

As shown in Figs. la and 2, the pressurised air exit pods 23 are located in the horizontal portions 16 of the conduit 7. In this embodiment, the conduit 7 has four pressurised air exit ports 23. However, it should be appreciated that two or more pressurised air exit ports 23 may be used.

The pressurised air exit ports, or air outlets, 23 are directed substantially upwards and are open to the atmosphere, which allows air from the conduit 7 to escape upwards therefrom. As shown in Fig. 1 a, the pressurised air exit pods 23 are substantially perpendicular to the horizontal portions 16 of the conduit 7. In this embodiment, the pressurised air exit ports 23 located closer to the filters 8 have a diameter of approximately 75 mm and the pressurised air exit ports 23 located closer to the top of the vertical portion 15 of the conduit 7 have a diameter of approximately 100 mm. However, it should be appreciated that other dimensions may be used.

It should be appreciated that more than one filter apparatus 1 may be used in each fish cage and/or fish farm. That is, the fish farm can comprise two or more filter apparatus 1, which are each connected to a source of compressed air. This provides a faster, more efficient removal of parasites from the water in the fish cages.

Providing a filter apparatus 1 as described above, and a method of operating the same, reduces the number of parasites attaching themselves to fish within the fish cages in fish farms. This is because the filter apparatus 1 reduces number of parasites located in the water from which the fish are harvested. This, in turn, reduces the time taken to process the fish for sale, and also increases the value of the fish, as they have less parasitic damage.

Modifications may be made to the foregoing embodiment without departing from the scope of the present invention.

For example, although the filter apparatus 1 has been illustrated and described above as including a pressurised air injection port 17 and at least one pressurised air exit port 23 to create the pressure differential in the conduit, it should be appreciated that the pressure differential may be created by a suction device, pump, or the like. In such an arrangement, the suction device, or pump is connected to the conduit 7 to create the pressure differential, which transports the water through the conduit 7 to the filter 8.

Furthermore, although the conduit 7 has been illustrated and described above has having two horizontal portions 16, it should be appreciated that the conduit 7 may include only one horizontal portion 16 with one filter 8. Similarly, it should also be appreciated that the conduit 7 may include two or more horizontal portions 16, with each horizontal portion 16 including a filter 8.

Also, although the gap 27 between the inner wall 26 of the coupling member 25 and the outer wall 7a of the conduit 7 has been illustrated above as being a partial toroid, it should be appreciated that the gap 27 may be any suitable shape to allow the pressurised air to enter the coupling member 25, surround the outer wall 7a of the conduit 7 and enter the conduit 7 via the apertures 28. The gap 27 may, for example, be annular, or at least partially annular, in shape.

Claims

Claims 1. A filter apparatus for filtering parasites from water comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected to the conduit; wherein the conduit comprises a pressurised air injection port and at least one pressurised air exit port, and wherein the pressurised air injection port, conduit and at least one pressurised air exit port are arranged such that, in use, when pressurised air is injected into the pressurised air injection port, a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.
2. The filter apparatus of claim 1, wherein the housing is configured such that it may float in water.
3. The filter apparatus of claim 1 or claim 2, wherein the housing is at least partially submersible.
4. The filter apparatus of any preceding claim, wherein the housing is substantially conical, pyramidal, frustoconical, frustopyramidal, or has an inverted cone shape, an inverted pyramidal shape, an inverted frustoconical shape, or an inverted frustopyramidal shape.
5. The filter apparatus of any preceding claim, wherein the housing includes a plurality of wall portions, the wall portions being substantially identical planar trapezoids.
6. The filter apparatus of claim 5, wherein the housing comprises eight wall portions such that the housing has an inverted truncated octagonal pyramid shape.
7. The filter apparatus of any preceding claim, wherein the housing includes a plurality of apertures, the apertures being arranged to allow water to flow into the housing when the apparatus is in use to aid the stability thereof.
8. The filter apparatus of any preceding claim, wherein the housing includes a base portion and the water inlet is located therein.
9. The filter apparatus of any preceding claim, wherein the housing includes a parasite attractant, the parasite attractant being a light source.
10. The filter apparatus of any preceding claim, wherein the housing includes one or more buoyancy members, the buoyancy members being attached to an upper portion of the housing.
11. The filter apparatus of any preceding claim, wherein the conduit comprises a vertical portion and at least one horizontal portion, the vertical portion being connected to the water inlet and the at least one horizontal portion being connected between the end of the vertical portion and the filter.
12. The filter apparatus of any preceding claim, wherein the filter is coupled to the outlet of the conduit.
13. The filter apparatus of any preceding claim, wherein the filter is located inside the housing.
14. The filter apparatus of any preceding claim, wherein the filter is a cartridge filter and is removable from the apparatus.
15. The filter apparatus of any one of claims 11 to 14, wherein the pressurised air injection port is located in a lower portion of the vertical portion of the conduit proximal to the water inlet.
16. The filter apparatus of any one of claims 11 to 15, wherein the pressurised air injection port comprises a coupling member, the coupling member being arranged to at least partially surround the vertical portion of the conduit and to provide a gap between an inner wall of the coupling member and the outer wall of the conduit.
17. The filter apparatus of claim 16, wherein the outer wall of the conduit adjacent to the coupling member includes a plurality of apertures, the apertures being configured such that, in use, pressurised air may flow from the pressurised air injection port, through the coupling member, and into the conduit.
18. The filter apparatus of any preceding claim, wherein the at least one pressurised air exit port is open to the atmosphere.
19. The filter apparatus of any one of claims 11 to 18, wherein the at least one pressurised air exit port is located in the at least one horizontal portion of the conduit.
20. The filter apparatus of any one of claims 11 to 19, wherein the at least one pressurised air exit port is located on an upper surface of the at least one horizontal portion of the conduit, such that, in use, air escaping from the conduit is directed upwards therefrom.
21. The filter apparatus of any one of claims 11 to 20, wherein the at least one pressurised air exit port is located between the end of the vertical portion of the conduit and the filter.
22. The filter apparatus of any one of claims 11 to 21, wherein the apparatus comprises two or more filters and the conduit comprises two or more horizontal portions, each horizontal portion being located between the end of the vertical portion and a filter.
23. The filter apparatus of claim 22, wherein each horizontal portion includes at least one pressurised air exit port.
24. The filter apparatus of claim 22, wherein each horizontal portion of the conduit includes a plurality of pressurised air exit ports.
25. A method of filtering parasites from water, the method comprising the steps of: providing a filter apparatus for filtering parasites from water comprising: a housing comprising: a water inlet; a conduit connected to the water inlet; a filter connected the conduit; wherein the conduit comprises a pressurised air injection port and at least one pressurised air exit port; connecting the pressurised air injection port to a source of compressed air; and injecting compressed air into the pressurised air injection port, such that a pressure differential is created in the conduit, which causes water to flow through the water inlet, conduit, and the filter.