Note: Descriptions are shown in the official language in which they were submitted.
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
Fish farm with a closed submersible unit
Technical field
The present invention relates to a fish farm with a closed submersible fish
pen i.e.,
a fish farm for fish, in particular salmon, including a submersible closed
unit, which
is attached to a floating collar through an immersion adjustment system for
positioning the closed unit below the water surface and in the water column.
The
invention also relates to supply and discharge of water to/from the closed
unit.
Object of the invention
One of the aquaculture industry's goals is for the sea to be used in a way
that
promotes environmentally sustainable development. The industry therefore seeks
to develop solutions that are energy efficient, reduce consumption of fossil
fuels
and reduce a climate footprint.
Today, the industry's biggest problems include diseases and parasites and in
particular the spread of salmon lice. Escaping fish is also a major problem
especially for the wild salmon stock - and is often due to technical failure,
incorrect
use of equipment or vessels, or storms. In addition, discharge of waste from
the
aquaculture industry has increased, and the industry accounts for large
amounts
of pollution in the coastal areas. The waste largely includes of waste from
feed and
excrements/faeces from the fish, but also waste from medicaments in used
during
for example, delousing. The environmental impact as a concentration of
pollution
from fish farms will be greatest just below or in the immediate vicinity of
the fish
farms, and the discharges could potentially affect life on the seabed and
change
the environmental conditions near the sites.
The abovementioned problems suggest that the industry needs closed facilities
to
prevent and reduce the environmental impact, and to ensure growth and
sustainability in the future. New locations in more weather-exposed areas at
sea
are considered to increase production.
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
2
Both closed and semi-closed fish farms where the purpose is to remedy the
noted
problems are already in use. Land-based plants are also used, but such plants
have so far proved problematic as the plants require considerable land use,
increased energy consumption, water consumption, sludge production and
significant investments. The technical and biological risk of land-based
production
is also significant.
Several of today's semi-closed facilities for use at sea are not completely
closed,
because the closed unit is not completely sealed. Examples include solutions
shown NO 344466 and NO 334524. None of these solutions are completely closed
or can be adjusted deep in the water column. They include a physical barrier
(wall
or cloth / net) that confines the fish from the surroundings. The environment
from
which the fish is sought to be delimited is mainly the upper water masses to
avoid
lice and other pathogens, while the waste substances are released as in
traditional
farmed nets. The disadvantages of these structures include that they are
cumbersome to operate, they do not sufficiently limit pollution from the
facilities,
and there is a great risk of breakdown due to the material of the net bags.
Patent NO 344466 relates to a combination of a lice skirt and dense steel wall
as a
barrier between fish and the environment in the upper water masses. This is a
newly developed steel structure and is not based on current conventional
farming
solutions. The invention can withstand a significant wave height (Hs) of 2.4
meters
compared to today's traditional 160-meter plastic rings that can withstand 4-6
meters (Hs). There is no collection of sludge and is thus an unsuitable
structure for
farming in fjords with reduced water exchange.
Patent N0334524 disclose a more traditional design. A physical barrier located
between the fish and surrounding water masses is either a waterproof or a
plankton-repellent material. This type of semi-enclosed cage is not very
suitable
for locations exposed to high currents and bad weather and will only provide
partial protection against the surrounding water masses. In the case of a
turbulent
flow image, the water masses on the outside and inside of the cage will mix.
This
structure uses several elements from current farming equipment but has no
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
3
solution to the sludge problem or solve utilization of aquaculture in weather-
exposed areas.
Background art
NO 332341 disclose a cage structure for fish farming with a closed cage
attached
to a floating collar, which is partially submerged. The invention includes an
inlet
line for supply of fresh water supplied through one or more water spreaders
and
has an outlet in the lower part of a bottom part of the cage, supplying water
and
waste via a drain line. NO 344177 also describes a closed cage for storing
fish on
their way to be to be slaughtered, where the cage can be lifted or lowered.
The
cage comprises one or more buoyancy chambers extending vertically in the cage,
for filling and evacuating a buoyancy medium in the form of water.
NO 342403 discloses a sealed cage arrangement which has a closed cage bag
with impermeable walls. The design has two or more floating collars to limit
the
forces imposed by the environment on the closed cage bag. One or more inlet
pipelines supply fresh water and at least one outlet pipe for water and waste.
A
method for treating the water to be supplied to the breeding cage is also
described.
NO 175341 relates to a device and a method for supplying water to a closed
cage.
Water is pumped from a depth that is deeper than the cage itself, and to a
water
spreader located at the inlet. The water is then distributed mainly
tangentially into
the cage to ensure circulation of the water inside the cage.
NO 178811 relates to a fish cage with a device for removing feed residues and
dead fish from the bottom part of the cage. The invention applied for is based
on
today's well-functioning farming equipment where it is the new closed
submersible
production unit with associated functioning components which is an innovation
and
the invention itself.
NO 332341 and N0342403 fails to disclose a completely closed submersible
production unit where the unit is attached to an adjustment system which is
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
4
attached to a floating collar, and where the device can be lowered below sea
level.
NO 332341 and N0342403 also fails to disclose a production unit with pressure
valves in the walls of the unit, for volume adjustment and water intake in the
centre
for optimal water circulation.
It is particularly pointed out that today's solutions only solve some of the
known
challenges facing the industry today. The production unit of the present
invention
will have a complete physical barrier against surrounding water masses in the
form
of a cloth or alternatively other flexible sealing materials. A completely
closed
production unit provides a controlled environment to ensure fish health and
the
ability to lower the unit below a water surface during periods of storms and
provides the ability to use more exposed locations at sea.
In patent NO 178811 only one collection system and one transport hose are used
to transport sludge and dead fish. Eide's invention differs significantly from
this in
that there are two separate collectors and two separate transport hoses to the
surface.
Another difference is also that several of the known inventions depend on
geodetic
water level inside the bag to ensure good expansion of the closed bags to
which
the inventions relate. There is thus a need for a higher water level on the
inside of
the fabric than on the outside. This extra water level causes extra weight in
the
structure of the system so that the floating collar is dependent on extra
buoyancy.
The invention applied for will not need such a structure because overpressure
will
be created inside the unit.
Furthermore, the water intake in several of the known art solutions is located
on
the side of the cage and must be pumped up to the surface either through or
over
the physical barrier between fish and the environment. The water supply unit
is in
several of the known systems mounted at the water surface or on a floating
collar.
The result is that the required pump is locate on the suction side rather than
on the
pressure side and is therefore relying on a rigid water intake (pipe), as a
flexible
intake (e.g. canvas) will collapse when the pump reduces the pressure in the
pipe.
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
Some prior art solutions rely on several pump units to create the desired
water
current configuration in a closed unit, because the pumps / water distribution
ports
are located at the side of the cages.
5 Drawbacks with prior art solutions include high energy consumption,
several pump
units, long pipes etc., and the solutions are considered to be complicated,
not
particularly cost-effective and very cumbersome structures.
The present invention seeks to solve these problems, and the invention
therefore
claims only one mechanical water supply /water lifting unit, since the water
supply
unit is located at the centre of the cage. The water is supplied through a
flexible
water distributor which also extending at the centre of a closed unit. The
present
invention will reduce the required head when pumping water and thus the
required
energy consumption.
Summary of the invention
The present invention relates to a fish farm including a traditional floating
collar
through an immersion adjustment system for positioning the closed unit in the
water column, further including a water supply unit such as a pump unit
(preferably
mechanical) for water located at the centre of the bottom of the closed unit
that
supplies new water into the unit. The closed unit further includes pressure
valves
located in the walls of the unit for volume adjustment.
Accordingly, the present invention discloses a fish farm adapted to be located
in a
body of water. The fish farm includes a floating collar. A closed unit is
attached to
the floating collar via an immersion adjustment system. The closed unit
includes a
water supply system including a water supply unit at a bottom of the closed
unit.
The water supply unit is adapted to supply and distribute water in the closed
unit
through a flexible water distributor. A waste system is adapted to remove of
waste
accumulated at the bottom part of the closed unit. A drain hose is adapted to
discharge waste from the waste system. A double barrier includes a net and a
sealing flexible barrier forming walls of the closed unit. Pressure valves are
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
6
adapted to control a pressure in the closed unit to a pressure exceeding an
ambient water pressure.
The net may be attached to at least one of an inside of the sealing flexible
barrier
and an outside of the sealing flexible barrier.
The closed unit may be kept unfolded and stable by a fastening device
extending
through the closed unit.
The water supply unit may be located at the centre of the closed unit.
The water supply unit may include a filter adapted to filter the water before
it is
supplied to the closed unit.
The flexible water distributor may include a vertical axis and a perimeter,
and
nozzles may be distributed along the perimeter and the vertical axis. The
nozzles
may be angled out from the water distributor to create circulation.
The closed unit may include a zipper, and at least a portion of the double
barrier of
the net and the sealing flexible barrier may be removable for physical access
to
the fish.
A jump fence may be releasable from the closed unit and may be adapted to be
hung along the upper part of the floating collar to prevent living organisms
from
escaping fish farm.
A waste system for dead fish may be located at the bottom of the net, while a
sludge and waste system may be located at the lower part of the sealing
flexible
barrier.
The fish farm may further include a dead fish hose adapted to transport
accumulated dead fish to the surface, and waste hose adapted to transport
sludge
and waste for further processing.
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
7
The waste system for collecting dead fish, sludge and other waste may be
located
in the lower part of the sealing flexible barrier.
The fish farm may further include a common waste hose adapted to transport
dead fish, sludge and waste to the surface for further processing.
The immersion adjustment system may be adapted to lower the closed unit below
the sea surface to a desired depth.
The immersion adjustment system may be adapted to control the depth of the
closed unit between a raised position and a lowered position at a desired
depth.
Furthermore, the invention relates to a method for supply and discharge of
water
to/from a fish farm as described above, comprising the steps of injecting
water into
the closed unit through the water supply unit located at the centre of the
closed
unit and further into the flexible water distributor and ensuring a pressure
inside
the closed unit, exceeding an ambient pressure with the pressure valves to
ensure
water exchange and volume control.
The method may further include injecting water through the water supply unit
and
through the flexible water distributor and distributing water homogeneously
throughout the closed unit through nozzles located in the water distributor,
where
the nozzles are angled to create circulation.
The method may further include releasing water and air through the pressure
valves to prevent an air pocket from occurring at the upper part of the closed
unit.
The production unit may have a complete physical barrier against surrounding
water masses. Suitable materials include flexible sealing materials such as
canvas. The completely closed unit separates fish and surrounding water masses
at all times, even when submerged.
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
8
The water supply unit is located at the centre of the production unit,
allowing a
single water supply unit will be sufficient. The mechanical water supply unit
may
alternatively be equipped with filtration means to filtrate the water before
it is
transported into the closed unit. The injected water will be homogeneously
distributed throughout the closed unit by a flexible water distributor with
nozzles,
for example by using a fabric tunnel, which will be able to provide
circulating flow
inside the unit. This gives the closed production unit a circulating flow from
the
centre and outwards, up and down the unit, which provides a supply of fresh
water
throughout the unit and welfare for the fish. This is enabled by the water
supply
unit and the water distribution from the centre. The water distributor will be
a
flexible sealed structure of cloth or tarpaulin, which can be folded. Oxygen
can be
added by, for example, mounting diffuser equipment on the flexible water
distributor for additional supply in the closed production unit.
The production unit is equipped with pressure valves in the walls of the unit,
which
will release the supplied water so that the bag at all times maintains the
best
possible shape by the overpressure. The pressure valves ensure good water
circulation and control the pressure inside the closed production unit, so
that there
is no danger of overfilling which could cause the bag to burst. Several
pressure
relief valves are installed in the top of the closed unit. A safety device
with valves
for compressed air inside the closed unit (eg Lift-up dead fish system), will
ensure
that if an air leak occurs, the valve will prevent a build-up of an air pocket
in the
closed unit which provides extra buoyancy so that the closed unit can lift.
The
safety device and the valves are designed such that that sludge, waste and
dead
fish do not escape, but are collected in the bottom part of the closed unit,
so that it
can be transported to the surface through a hose. This ensures favourable
environmental conditions for the fish.
Attaching the closed unit to an existing plant structure (floating ring with
bottom
ring) or another type of cage with alternative weights, it will be possible to
lower
the closed unit below the sea surface. This will be done by means of, for
example,
a winch, or any equipment for adjusting the closed production unit below the
water
surface and in the water column. The invention reduces the risk of escaping
fish
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
9
and the risk of getting in conflict with floating elements, storms and waves
present
at the water surface. The closed production unit in the submerged state will
have
less load and wear on the structure and have an extended service life in
contrast
to other closed concepts which must withstand forces from waves, current and
movements present at the sea surface. The closed unit will also have a keeper
net
/ seine, to provide a double barrier against escape.
There will be a distance between the inner net and the outer sealing flexible
structure (in the form of canvas or other sealing flexible barrier) in the
bottom part
of the cage. This allows sludge and other waste to fall through the net and
down
into the bottom part of the outer sealing flexible structure where it is
transported to
the surface for further processing. Dead fish are collected at the bottom of
the net
and are transported to the surface through a hose, separate from the sludge.
Alternatively, the sealing flexible structure can also be located on the
inside of the
net. In this embodiment, dead fish, sludge and other waste will be collected
at the
bottom of the flexible material, and then collectively transported to the
surface for
processing.
Brief description of drawings
Figure 1 is a schematic representation of a submersible closed unit, where a
double barrier includes nets attached to the inside of a sealing flexible
barrier,
including the structure installed in an adjustment system;
Figure 2 shows an embodiment of the water intake and waste management
elements;
Figure 3 shows a design of the valves;
Figure 4 shows a design of the submersible closed unit installed in an
adjustment
system;
Figure 5 is a schematic representation of a flexible water distributor;
Figure 6 is a schematic representation of the submersible closed unit
according an
embodiment of the invention, seen from above;
Figure 7 shows an embodiment of a submersible closed unit in its entirety,
where
the double barrier includes of a flexible sealing material attached to the
inside of a
CA 03212807 2023-09-07
WO 2022/191716 PC T/N02022/050063
net, with indicated figures on the individual parts included in the structure
installed
in an adjustment system; and
Figure 8 shows the closed unit in three stages, including the surfaced state
in the
first drawing, the closed unit immersed to 10 meters in the second drawing and
the
5 closed unit immersed to 35 meters in the last drawing.
Detailed description of the invention
Figure 1 shows a traditional submersible farming aquaculture cage, with a
submersible closed unit 1 for use in the aquaculture industry. Fresh or
seawater
10 will enclose the cage and the walls of the closed unit will form a
physical barrier /
barrier to the aquatic environment outside the closed unit 1. The structure
outside
the closed unit 1 will be open and water may enter this area.
The submersible closed unit 1 will be equipped with a double barrier including
of
net 11 and a sealing flexible barrier 12 in the form of, for example,
fabric/canvas/tarpaulin. As shown in figure 1, this can be done by fastening
the net
11 on the inside of the sealing flexible barrier 12, by fastening device 29
which is
continuous throughout the unit 1. The fastening device 29 will keep the net 11
stable and unfolded inside the closed unit 1.
The closed unit 1 is supplied with water through a water supply unit 2 located
in
the centre of the closed unit 1. Injected water is then distributed by a
flexible water
distributor 3 in the closed unit 1. Nozzles 23 around and along the vertical
axis of
the flexible water distributor 3 distributes the water homogeneously
throughout the
closed unit 1 and provides a circulating flow. To ensure further circulation
in the
closed unit 1, the flexible water distributor 3 can be equipped with nozzles
23
which are angled out from the water distributor 3. This will help control the
water
flow and create circulation of the water masses inside the closed unit 1.
The water is transported out through valves 4 to ensure good water exchange
and
water mass flow control. The valves will be open at elevated pressure 15 and
will
be closed 16 if the pressure falls below a certain value, as shown in figure
3. The
CA 03212807 2023-09-07
WO 2022/191716 PC T/N02022/050063
11
number and location of the valves 4 may vary and will depend on the size of
the
closed unit 1.
The net 11 is located on the inside of the sealing flexible barrier 12 of the
closed
unit 1. The net 11 provides for extra safety against escaping fish and ensures
a
gentle handling of the fish during handling, drying and various operations.
The collection system for dead fish 14 is located at the bottom of the net 11,
while
the sludge and waste system 13 is located in the lower part of the sealing
flexible
barrier 12. Dead fish are transported to the surface by means of dead fish
hose 7
and sludge and waste through waste hose 6, for further processing. The water
supply unit 2 is designed to prevent it from conflicting with dead fish hose 7
or
waste hose 6 and will constantly supply fresh water to the submersible closed
unit
1.
The submersible closed unit 1 will be attached to an adjustment system 28 for
immersion in the water column. Such systems are known from the prior art.
Figure 4 disclose an example of a method where the closed unit 1 is part of an
adjustment system 28 which is attached to a floating collar 5 with a bottom
ring 10
as a weight. The closed unit 1 will be attached to the adjustment system 28
through a fastening loop 9. The closed unit 1 will be kept unfolded by the
bottom
ring rope / weight rope 17 by a loop 19 and rope 20 arrangement. A raising and
lowering unit 22, preferably in the form of, for example, a winch, can adjust
the
winch rope 8 length and thus raise and lower the closed unit 1, allowing it to
be
lowered below the sea surface. A stop element 21 is also fitted to prevent
wear
between the closed unit 1 and the bottom ring 10 if the raising and lowering
unit 22
collapses. Sliding rings 18, allow the closed unit to slide along the bottom
ring rope
17 so that it maintains its shape below the water surface and in the water
column.
Figure 6 shows the submersible closed unit 1 seen from above, in the same
embodiment as the rest of the structure. Pressure relief valves 4 are
installed to
release water and air to prevent air pockets to form in the upper part of the
closed
CA 03212807 2023-09-07
WO 2022/191716 PCT/N02022/050063
12
unit 1. The pressure relief valves 4 are the same as those located in the wall
of the
closed unit 1 shown in Figures 1 and 3. The number and location of these
pressure relief valves 4 may vary according to the size of the unit. The roof
of the
structure can be removed in connection with the delivery of fish for slaughter
or
other operations that require physical access to the fish. When the
submersible
closed unit 1 has been lifted to the surface, it must be possible to release a
jumping prevention net 24 from the fabric and hang it up along the upper part
of
the floating collar 5 to prevent fish from jumping out of the cage.
Figure 7 shows an alternative embodiment where the double barrier is made by
fastening a sealing flexible barrier 31 on the inside of a net 30, with a
fastening
device 29 which is continuous throughout the closed unit 1. The fastening
device
29 will keep the sealing flexible barrier 31 stable and unfolded. Water is
supplied
as described in relation to Figures 1, 2 and 5.
The valves 4 will be attached to the sealing flexible barrier 31 in the same
way as
in Figures 3 and 6, and the waste management system 32 for collecting dead
fish,
sludge and other waste will be mounted in the bottom of the sealing flexible
barrier
31 after which dead fish, sludge and other waste are transported through a
common waste hose 33 out of the unit. Regarding immersion of the closed unit
1,
this can also be carried out in the same way as the procedure indicated in
Figure
4.
As shown in Figure 8, is it possible adjust the depth of the closed unit 1 in
the
water column. The unit can be raised to a maximum uplifted condition 25, be
immersed to a depth of 10 meters 26 and can be lowered further into the water
column to the desired depth 27. The adjustment system 28 will determine how
far
into the water column (how deep) the closed unit 1 can be lowered.
The term fish farm is not intended to restrict the invention to "fish"
farming. The
term "Fish farm" is intended to cover a farm used for rearing any type of
marine
organisms. The closed unit forms the fish habitat or residence chamber.
