Field of the invention

[0001] The present invention relates to a pump assembly for the supply of oxygen rich water in a fish farming cage, more specifically an assembly for pumping water from a desired depth into a fish farming cage, together with a method for improving the aquatic environment in a fish farming cage.

Introduction

[0002] The invention applies to an assembly for improving the aquatic environment in a fish farming cage at sub-optimal environmental conditions. The device is a pump arrangment comprising an electric driven propeller where the propellers axis is oriented vertically and installed inn an upper part of a vertically oriented plastic pipe that conducts water from a larger depth and guides the flow of water to the surface and distributes the flow of water outwardly in such a manner that a vertical flow in the fish farming cage is set up outside the arrangment due to temperature and density differences in the water that arrives at the surface. The arrangement increases the efficiency of such a flow and reduces the power consumption by isolating the upward rising water flow in the bulk of the water column from intake to discharge. At the same time, the arrangement will have an aditional effect when utilized in combination with conventional delousing skirts. The surroundings will be protected by installing a strainer/grating at the intake and the discharge, to prevent that fish in the fish farming cage are injured. The device is mounted to a standardized buoy with a strap at the discharge side, and a weight is mounted at the intake side in order for it to keep in a stable position vertically and at an equilibrium position with regard to a desired water depth. The device is also fastened in the fish farming cage with ropes to the fish cage floating collar.

Background art

[0003] The aquaculture industry faces challenges to avoid parasite attachment (sea lice) and damaging micro-organisms such as amoebic gill disease (AGD) . Full or near utilization on an annual basis of the use of de-lousing skirts is today widespread to hinder the attachment of lice present and lice arriving via horizontal currents in the upper part of the water column. The use of such skirts can incur reduced oxygen levels and stagnent water columns that have a negative impact to the fishes welfare, growth and possible attachment of micro-organisms. For some sites there are situations where stagnant water occurs during certain periods, or there are other working operations where there is a need to increase the circulation by retrieving oxygen rich water from deeper water depths or to remove waste products during a period of time.

[0004] NO20150705A1 describes a device for pumping water with the purpose of replacing or removing an upper layer in fish farming cages where a de-lousing skirt is utilized to prevent lice infected water from penetrating into the cage. The device according to the patent application comprises of a vertical pipe with mounted weights, a grating at the end of the pipe to ensure that fish can not swim up and into the inlet hose, a pump and an electrically operated propeller with a vertical oriented axis in the upper part of the pipe, where the pipe is hooked up to an intake ring for water that has slit apertures and a bouyancy element. According to the patent application, the device sucks in water through the intake ring at the surface and pumps this down via the discharge hose that extends far down to the deep portions of the fish farming cage.

[0005] Other patent publications are WO2014/000102A1, NO19832490A and

WO2007/066388A1, all of which describe the background art.

Short summary of the invention

[0006] The invention is a pump device for the supply of oxygen rich water in a fish farming cage with a flotation collar (M) and net (x), where the pump device comprises:

- a vertically oriented plastic pipe (d),

- an electrically driven propeller (a) with a vertical axis and arranged in the upper portion of the plastic pipe (d),

- where the propeller is arranged below two distribution pipes (b) and where the distribution pipes (b) have a grating located on top,

- where the plastic pipe is arranged with a suspension (g) for a buoy (f) that is floating at sea level,

- where the plastic pipe (d) is arranged with a strainer (c) at its deepest end,

- where the plastic pipe (d) is arranged with a weight (3) close to the deepest end, and

- where the pump device is arranged to pump oxygen rich water (1) from a desired depth in the fish farming cage and distribute this.

The invention is, in another aspect, a method for improving the aquatic environment in a fish farming cage to prevent or reduce the attachment of parasites or microorganisms on fish, characterized in the following steps:

- installing a pump assembly in a fish farming cage with a floatation ring (M) and net (x), where the pump assembly comprises of the following :

- a vertical oriented plastic pipe (d),

- an electric driven propeller (a) with a vertical axis and arranged in the upper portion of the plastic pipe (d),

- where the propeller (a) is arranged below two distribution pipes (b) and where the distribution pipes (b) have a grating located on top,

- where the plastic pipe (d) is arranged with a support (g) for a buoy (f) that is floating at sea level,

- where the plastic pipe (d) is arranged with a strainer (c) at its deepest end;

running the pump assembly and thus pumping oxygen rich water (1) from a desired depth and distributing the oxygen rich water (2) from the distribution pipes (b) close to the surface, and where the distributed oxygen rich water (2) due to its higher density intiates and starts a vertical return flow (3) towards the bottom of the fish farming cage.

[0007] The purpose of the invention is to be a specific technical assembly that can be mass produced, sold and installed in any fish farming cages whereby deriving so in this manner to a method in the industry for improving the fishes well-being by creating a circulation and vertical flow in such an effective way when needed.

Figure captions and reference to embodiments of the invention

[0008] The attached figures illustrate some embodiments of the claimed invention.

[0009] By the term operative unit is ment that a unit is arranged to perform the active actions that are involved in the process. In addition, acording to the invention, the assembly may contain passive units and components such as a bouy for bouyancy, weights, standardized steel components and ropes for fixation of the device in a desired position.

[0010] Fig. 1 depicts schematically a vertical cross section of a fish farming cage under water with units that constitute a part of one embodiment of a device according to the following invention.

[0011] Fig. 2 shows a vertical cross sectional view of an embodiment of the invention the present invention with a de-lousing skirt.

[0012] Fig. 3 shows the water flow seen from below viewed at a slant angle as one embodiment of the invention.

[0013] Fig. 4 shows as one embodiment of the invention and the water flow seen from above viewed at a slant angle in a fish cage with a de-lousing skirt.

[0014] Fig. 5 shows the device according to the invention. [0015] Fig. 6 shows the same as figure 5 but viewed from a different angle.

[0016] Fig. 7 shows the upper part of the device according to the invention.

[0017] Fig. 8 shows as one embodiment of the invention with the fixation by a rope to a floatation collar.

Description of embodiments of the invention

Fig. 1 depicts schematically a vertical cross section of a fish farming cage under water with components (a-g) of the device according to the present invention. The electrical propeller (a) is arranged in the plastic pipe (d) which displaces water from the intake with a strainer (c) to the outlets with grating (b). The oxygen rich water masses (1) from deeper water layers are displaced up through the pipe of the device and spread out at the surface (2) for subsequentially to gradually sink and set up a vertical flow (3) due to temperature and density diferences. In this way one prevents stagnant water masses which is disadvantageous with regard to attachment of microorganisms and general fish welfare. The device used with a de-lousing skirts or louse tarpaulin (LS) which shields horizontal flow (H) with louse in the upper water layers from reaching fish inside the net (x), will obtain the effect well for the fish inside the fish cage. De-lousing skirt (LS) and net (x) arranged from a floating collar (M) is not the characterizing part of the invention but constitutes part of its context. Floating buoy (f) with support (g) to the device, see Figs. 5 and 6, and weight (e) shall contribute to keeping the device in a vertical position and keep its balance with regard to desired depth. This is controlled by adjusting the length of the connection (g), see Fig. 6, between the device and the buoy (f) .

[0018] Thedevice according to the invention may comprise so called units and components such as bouy (f) for bouyancy, weight (e), standardized steel components and ropes (i) for keeping of the device in a required position. Figure 8 depicts an embodiment of the invention with fixation with three ropes (i) that extend to three points on a floatation collar (M).

[0019] The device according to the invention is a simple embodiment and is assembled, whenever possible, from available standardized components so as to adhere to regulations that fish farms are subject to, for example the NYTEK regulations and the Norwegian Standard NS9415. That may be related to certified bouys, lines, ropes, shackles, chains, weights, plastic pipes and plastic details that are welded to the pipe to form fastening details for anchoring. It is therefor important that such a device is shaped so it can be certified or be defined as additional equipment and form part of the facilities certificate according to the NYTEK regulations. The requirement in this regard relates to that such an device shall be assumed as auxiliary equipment and assume for not having properties that may represent increased risk of escape. The device according to the invention is therefor made so simple and streamlined as possible in order to avoid contact with or cause abrasion against other components.

[0020] A lot of effort has been put in place in order for the device to be mass produced in a simple manner based upon known and durable materials that are used within the aquaculture industry. It shall be possible to place one or several devices in or around each fish farming cage as needed and in this manner typically have several devices in operation at one fish farming facility.