WO2020233729A1

WO2020233729A1 - Aeration and oxygenation equipment intended in particular for fish farm tanks

Info

Publication number: WO2020233729A1
Application number: PCT/CZ2020/050027
Authority: WO
Inventors: Ján Regenda
Original assignee: Jihočeská Univerzita V Českých Budějovicích
Priority date: 2019-05-21
Filing date: 2020-04-29
Publication date: 2020-11-26
Also published as: EP3972408A1; CZ308381B6; CZ2019315A3

Abstract

The aeration and oxygenation equipment intended in particular for fish farm tanks (2) brings the possibility of aeration and oxygenation of water in a fish farm tank (2) without a need for a heavy weight and or any obstacles to fish harvesting. The fish farm tank (2) is fitted with a special thin-walled aeration adapter (1) with oxygenation which is not self-supporting but copies the walls (12) and bottom (11) of the fish farm tank (2). Under the bottom (13) of the aeration adapter (1) in the central part two distributing aeration rings (3, 3´) and one distributing oxygenation ring (4) are placed. The bottom (13) of the aeration adapter (1) is above the distributing aeration rings (3, 3´) and the distributing oxygenation ring (4) perforated by aeration openings (16) and oxygenation openings (17), through which air and oxygen bubbles are released into the fish farm tank (2).

Description

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Aeration and Oxygenation Equipment Intended in Particular for Fish Farm Tanks

Field of the Invention

The invention concerns the field of fish farming, specifically aeration and oxygenation equipment intended in particular for fish farm tanks.

Background of the Invention

Fish farm tanks are used for short-time storage of fish, most commonly during fish harvesting out of a pond or fish sorting at a fish farm. Fish farm tanks are also utilized when fish is sold, namely at Christmas time. Generally, conditions in the fish farm tanks are rather exhaustive for fish. They are characterized by a relatively high amount of biomass, which usually means stress and lack of oxygen. Lack of oxygen is dangerous for fish. It is related to an increasing level of carbon dioxide produced by fish breathing and organic matter decomposition as well as to changes in the pH value of water. From the point of view of the fish welfare, i.e. the preservation of basic conditions for life, well-being and health of the animals and their protection against negative agents potentially detrimental to their health, causing pain, suffering and mental damage, the most controversial is one-day fish harvesting out of smaller ponds. It is there where the quality of water in the fish farm tanks is deteriorated considerably, in particular due to an increase in turbidity and a decrease in oxygen content. In the morning on the fish-harvesting day, the fish farm tanks are filled by water from the fish collecting pool. In the course of the fish-harvesting day it is necessary to refill or replace water in the fish farm tank to compensate the amount of water lost by the fish biomass increasing volume, or ensure enough oxygen for the fish where applicable. The water found in the fish-collecting pool is usually rather contaminated by undissolved matter and low in oxygen. Ultimately, this may make the situation in the fish farm tank even worse. The main fish, i.e. carp, is a bit more resistant to such conditions. In addition, it is usually not kept in fish farm tanks for long as it is quickly loaded and taken away from the pond. The most endangered in this respect are the supplementary species of fish, such as smaller carp, tench, grass carp, silver carp, perch, catfish, white fish, etc. or where applicable the fish that is less frequently harvested during the fish-harvesting day and must wait in the fish farm tanks for a longer time before it is possible to take it away from the pond. Fish consume oxygen dissolved in water for breathing. Oxygen is absorbed into blood via the fish gills. If the value of dissolved oxygen is optimal, the fish thrive, grow and is in very good condition. The content of oxygen in water depends on the temperature of water and therefore so-called saturation with oxygen is monitored and quantified as a percentage. Saturation with oxygen should be higher than 50%. Oxygenation of water is preferably performed by aeration equipment producing bubbles that cover a distance of 30 cm in 1 second. If this condition is fulfilled, up to 50% of oxygen is dissolved in water.

In fish farming, blowers, air pumps, and compressors with required pressure and capacity of supplied air are used. To obtain effective aeration or airing treatment, the source of air must overcome the hydraulic pressure of water of corresponding to approximately 125 mm Hg caused by the pressure of water in the tank, friction in the air supply line, and the aeration equipment. In addition, aeration can be used at the water inlet to the tank through various spraying adapters or injectors based on the Venturi tube principle. To increase the content of oxygen in water, special equipment, so-called oxygenators, can be utilized, which produce air with a higher content of oxygen or oxygen of the purity of 80% to 90%. In professional fish farms, oxygenators are widely used although their purchase price is high. The reason is that their long-term operation is more economical than that of a pressure cylinder with oxygen or a tank containing liquid oxygen. Compressed oxygen in pressure cylinders is used for not regular consumption and as a stand-by source. When using oxygen, rules for safe storage and use must be adhered to. Liquid oxygen evaporates in time.

Fish farm workers try to maintain good conditions for fish in the tanks by water replacement, by water shovelling in the tanks or by aeration or oxygenation. In larger ponds, injection of fresh water that regularly refills and replaces water in the tanks is applied. Flowever, this approach is difficult in the case of smaller ponds where no source of fresh water is available during fish-harvesting. Sometimes an aeration or oxygenation hose is used in the tanks as well. To prevent the aeration hose from spontaneously floating to the surface, the hose must be sufficiently loaded by a weight. Flowever, this limits fish-harvesting by a scoop net and also mechanical damage to fish by the reinforcement and weight is imminent. Simply said, the hose and its weight also hinder in the tank.

Therefore, the task of the invention is the creation of such aeration and oxygenation equipment, intended in particular for fish farm tanks, that would remove the aforementioned drawbacks, provide an active supply of oxygen into water in the fish farm tanks and that would also stir water and that could be easily installed in any fish farm tank of any shape and size that is used today by fish farmers.

Summary of the Invention

The set task is fulfilled by the aeration and oxygenation equipment intended in particular for fish farm tanks of the present invention. The essence of the invention rests in the fact that the aeration and oxygenation equipment consist of a thin-walled aeration adapter with oxygenation, compressed air supply line, and compressed oxygen supply line connected to the aeration adapter with oxygenation. The aeration adapter with oxygenation is not self- supporting but its shape corresponds to the inner surface of the tank, i.e. copies the walls and bottom of the fish farm tank, is adapted to be put into the tank and is also fitted with fastening elements for attaching the equipment to the tank edges. The aeration adapter with oxygenation consists of the bottom that is perforated by aeration openings and oxygenation openings through which air and oxygen bubbles are released into the space of the fish farm tank, and of the shell connected to the bottom that is shaped to sit onto the inner surface of the tank. Arranged under the bottom of the aeration adapter with oxygenation, there is at least one distributing aeration ring with aeration pores connected to the compressed air supply line supplying air and at least one distributing oxygenation ring with oxygenation pores connected to the compressed oxygen supply line. In addition to the aeration and oxygenation equipment, the compressed air supply line is connected to the central air distribution system downstream the blower or compressor and the compressed oxygen supply line is connected to the oxygen pressure cylinder. After the blower and oxygen pressure cylinder are connected, water in the fish farm tank is agitated with air and water in the central part of the fish farm tank rises to the water surface and sinks along the perimeter of the fish farm tank at the wall thereof. Water sinking along the perimeter of the fish farm tank occurs against the flow of tiny bubbles of oxygen. Thanks to this, bubbles are decelerated on their rise towards water surface and oxygen is utilized better. Aeration in the fish farm tank serves primarily for the agitation of water in the fish farm tank and secondarily for the supply of oxygen from air thus enriching water in the fish farm tank with oxygen. On the other hand, released liquid oxygen saturates water with oxygen much more effectively. Thanks to the combination of aeration and oxygenation in the fish farm tank, the content of oxygen is higher and is distributed throughout the entire tank more evenly. In addition, the aeration and oxygenation equipment does not limit the movement of fish in the fish farm tank or harvesting thereof by a scoop net or any other fishing gear as it is placed under the second bottom, i.e. the bottom of the aeration adapter with oxygenation. The aeration adapter with oxygenation is prevented from rising to the surface by a weight and its fixation at the edge of the fish farm tank.

In a preferred embodiment the compressed air supply line and/or compressed oxygen supply line are arranged on the outer side of the shell, i.e. in the space between the outer side of the shell of the aeration adapter with oxygenation and the inner surface of the fish farm tank. In another preferred embodiment, the compressed air supply line and/or compressed oxygen supply line are integrated in the shell, e.g. in the joint or weld of the shell.

In a preferred embodiment, the design of the shell of the aeration adapter with oxygenation may be arranged in minimalist style and reduced to three belts that are in the lower section connected by the bottom of the aeration adapter with oxygenation and are arranged along 20 to 50% of the perimeter of the bottom of the aeration adapter. In another preferred embodiment, the design of the shell of the aeration adapter with oxygenation is comprised of one solid belt forming a cylinder or cone arranged along the entire perimeter of the bottom of the aeration adapter. The bottom and shell of the aeration adapter with oxygenation thus cover the entire inner surface of the fish farm tank.

In a preferred embodiment, the bottom of the aeration adapter with oxygenation is created in the shape of a circle. The distributing aeration ring is preferably created in the shape of a circle with aeration pores with the diameter of 0.8 and 0.9 mm for the penetration of air into the aeration openings of the aeration adapter with oxygenation or into the inner space of the fish farm tank where applicable, and is positioned at the bottom of the fish farm tank. The distributing aeration ring may be porous and therefore air-permeable in its entire profile. The distributing oxygenation ring is also in the shape of a ring with oxygenation pores with the diameter ranging from 0.05 to 0.2 mm in the number of 10 pieces per 1 cm for the penetration of oxygen into the oxygenation openings. The distributing aeration ring and distributing oxygenation ring are deployed under the bottom of the aeration adapter with oxygenation. In a preferred embodiment, under the circular bottom in the central part are arranged in a circle two distributing aeration rings and one distributing oxygenation ring with a different diameter where the first distributing ring has the diameter n and the second distributing ring has the diameter r₂ and the distributing oxygenation ring has the diameter r₃, where n £ r₂ £ r₃. The bottom of the aeration adapter with oxygenation may also be angular to be placed in an angular fish farm tank, i.e. the distributing aeration rings as well as the distributing oxygenation ring may also be in the shape of a square or rectangle. The compressed air supply line and compressed oxygen supply line are fitted with valves to control the volume of air and oxygen supplied into the inner space of the fish farm tank.

The fastening elements are preferably created as a rim of the shell to be folded over the edge of the fish farm tank along its perimeter or at least in three points using rubber fabric or a rubber tape or rubber tension rope to fasten the aeration adapter to the means of fixation created on the fish farm tank. The fixation of the shell into the fish farm tank using pins or lugs or dowels through small openings with the diameter ranging from 5 to 25 mm in the shell and the fish farm tank immediately under their upper edge is possible as well.

The aeration adapter with oxygenation is made of a light-weight material that keeps a given shape, preferably polypropylene, laminate, carbon fibre reinforced polymers and/or a different lightweight and corrosion-resistant material.

The bottom of the aeration adapter with oxygenation is reinforced by a system of supports in the shape of radial or circular ribs with the height of the ribs ranging from 2 to 6 cm, where the ribs are fitted with through openings for the passage of the distributing aeration ring and the distributing oxygenation ring, and/or the distributing aeration ring and the distributing oxygenation ring is fixed to the circularly arranged ribs. This arrangement prevents the lifting of the distributing aeration ring or the distributing oxygenation ring or where applicable the bottom of the aeration adapter.

When the aeration adapter with oxygenation is operated, the air stream will rise water in the centre of the fish farm tank to the water surface from where the water will flow towards the tank perimeter where it will sink back to the bottom of the aeration adapter with oxygenation. On the other hand, tiny bubbles of oxygen will rise along the perimeter of the fish farm tank wall against the water flow. Thanks to this arrangement, water in the fish farm tank will be actively oxygenated and also stirred. If the use of aeration adapter with aeration as well as oxygenation is not necessary, the fish farm tank may be operated in a standard way without the adapter and any limitation. A great advantage of the aeration adapter is the fact that it can be installed without much difficulty onto the most widely used types of fish farm tanks. Therefore, it is not necessary to purchase any new fish farm tanks for its operation.

The advantages of the aeration and oxygenation equipment intended in particular for fish farm tanks of the present invention rest in the fact that they provide active oxygenation of water in fish farm tanks and stirring of water in the tanks and that they can be installed without much difficulty in any fish farm tank of any shape and size. The inner space of the fish farm tank with the aeration adapter with oxygenation according to the present invention is smooth and free, is not limited by hoses and weight. All important components are deployed under the bottom of the aeration adapter with oxygenation, or behind the shell of the aeration adapter where applicable.

Explanation of Drawinqs

The present invention will be explained in detail by means of the following figures where:

Fig. 1 shows a plan view of the aeration and oxygenation equipment,

Fig. 2 shows a plan view of the aeration adapter with oxygenation,

Fig. 3 shows the A-A section of the aeration and oxygenation equipment,

Fig. 4 shows the B-B section of the aeration and oxygenation equipment,

Fig. 5 shows a view of the aeration and oxygenation equipment with three belts of the shell.

An Example of the Invention Embodiment

The principle of the aeration and oxygenation equipment intended in particular for fish farm tanks 2 is that the fish farm tank 2 is fitted with the aeration adapter 1 with oxygenation made of a thin material, in this case polypropylene or PP with the width of 5 mm, which copies the inner walls 12 of the fish farm tank 2 as closely as possible. In a different example of embodiment, the aeration adapter with oxygenation can be made of laminated plastic or carbon fibre reinforced polymer. The design of the aeration adapter with oxygenation is not self-supporting in water and fully rests on the bottom ϋ of the fish farm tank 2 and the wall 2 of the fish farm tank 2 and due to this fact its design is economical and cost- efficient. The circular bottom 13 of the aeration adapter 1 with oxygenation is approximately 5 cm above the bottom H of the fish farm tank 2. In another example of embodiment, the bottom of the aeration adapter 1_ with oxygenation can be angular, provided that the bottom 1_1_ of the fish farm tank 2 is angular. The space between the bottom 1_1_ of the fish farm tank 2 and the bottom 13 of the aeration adapter 1_ with oxygenation is filled with a system 9 of supports arranged in the shape of radial ribs placed under the bottom 13 of the aeration adapter 1_ with oxygenation as shown in Fig. 2. In the space under the bottom 13 of the aeration adapter 1_ with oxygenation in its central part, through the through openings in the ribs, making a circle, aeration hoses representing the distributing aeration rings 3, 3^' and the distributing oxygenation ring 4 will be arranged. In this example of embodiment, two distributing aeration rings 3, 3^' and one distributing oxygenation ring 4 are used as shown in Fig. 1 . The distributing aeration rings 3, 3^' and the distributing oxygenation ring 4_have different diameters; the smaller first distributing aeration ring 3 has the diameter n = 30 cm, the larger second distributing aeration ring 3^' has the diameter r₂ = 70 cm and the distributing oxygenation ring 4 has the diameter r₃ = 90 cm. In another, not shown example of embodiment, multiple distributing aeration rings 3, 3^' can be used, namely three, and/or only one and similarly, the number of the distributing oxygenation rings 4 can be higher, depending on the size of the fish farm tank 2. Each distributing aeration ring 3, 3^' has aeration pores with the diameter ranging from 0.8 to 0.9 mm for the penetration of air into the aeration openings 16 and the distributing oxygenation ring 4 has the oxygenation micropores with the diameter of 0.12 mm in the quantity of 10 pieces per 1 cm for the penetration of oxygen into the oxygenation openings 17.

The bottom 13 of the aeration adapter 1_ with oxygenation above the distributing aeration rings 3, 3^' will be open in the shape of narrow pores of the aeration openings 16, through which air will be released from the micropores in the distributing aeration rings 3, 3^' towards the water surface, and in the shape of oxygenation openings 17, through which oxygen will be released from micropores in the distributing oxygenation rings 4. The supply line 5 of compressed air to the distributing aeration rings 3, 3^' and the supply line 6 of compressed oxygen to the distributing oxygenation ring 4 under the bottom 13 of the aeration adapter 1 with oxygenation will be specifically adjusted and routed under the shell 14 and bottom 13 of the aeration adapter 1. with oxygenation into the distributing aeration rings 3, 3^' and the distributing oxygenation ring 4, as shown in Fig. 3. The supply line 5 of compressed air and the supply line 6 of compressed oxygen are routed to the fish farm tank 2 separately. In a another example of embodiment, the supply line 5 of compressed air is integrated in the shell 14 of the aeration adapter 1_ with oxygenation so that the side walls of the aeration adapter 1_ with oxygenation forming the shell 14 of the aeration adapter 1_ with oxygenation are connected and/or welded together via a thin tube, in which or using which air from the central distributing hose outside the fish farm tank 2 is supplied into the space at the bottom U of the fish farm tank 2. The supply line 5 of compressed air is therefore specifically led out via the tube connecting the walls, i.e. the shell 14 of the aeration adapter with oxygenation. The purpose is to ensure that in the space of the fish farm tank 2 no obstacles are created by the hoses or elements of the supply line 5 of compressed air or the supply line 6 of compressed oxygen. The shell 14 of the aeration adapter 1_ with oxygenation, or where applicable the wall 12 of the fish farm tank 2, as well as the bottom 13 of the aeration adapter 1_ with oxygenation, or where applicable the bottom U of the fish farm tank 2 must be smooth, must not damage fish and must allow its trouble-free harvesting into a scoop net or a landing net. The height of the side wall of the shell 14 of the aeration adapter 1_ with oxygenation will be at the level of the edge of the fish farm tank 2.

Spontaneous floating of the aeration adapter 1 with oxygenation to the water surface will be prevented by fastening elements 7, specifically using at least three flat rubber tension ropes 10, (so-called “gumicuk” in Czech), as shown in Fig. 4. One end of the fastening element 7 will be attached on the aeration adapter 1 with oxygenation while the other end of the fastening element s will be attached over the rim of the fish farm tank 2 under its outer edge to the means of fixation 8 on the fish farm tank 2, ideally onto a rubber block used for the separation of fish farm tanks 2 during storage and transport. This will prevent spontaneous floating of the aeration adapter 1_ to the water surface. There are of course alternative methods of fixing the aeration adapter 1 with oxygenation to the fish farm tank 2, such as using pins put through an opening in the uppermost part of the fish farm tank 2 and the aeration adapter 1 with oxygenation, as in the case of cuff-links, or using dowels. The shape of the aeration adapter 1 with oxygenation copies the shape of the fish farm tank 2, which means that also an angular shape is possible.

The design of the aeration adapter 1 with oxygenation may be reduced in minimalist style to three straps or belts 15, which will be connected in the lower part by the bottom 13 of the aeration adapter 1 with oxygenation and along one side of one of the belts 15 in a protecting tube, the supply line 5 of compressed air will be routed into the distributing aeration ring 3, 3^' under the bottom 13 of the aeration adapter and along one side the other belt 15 in the protecting tube, the supply line 6 of compressed oxygen will be routed into the distributing oxygenation ring 4 under the bottom 13 of the aeration adapter with oxygenation. In their upper parts, the belts 15 will be fixed to the fish farm tank 2, as shown in Fig. 5. The belts 5 are arranged along 30% of the perimeter of the circular bottom 13 of the aeration adapter 1 with oxygenation.

Industrial Applicability

The aeration and oxygenation equipment intended in particular for fish farm tanks can be used with any known and used fish farm tank. It is especially suitable for the most widely used standard laminate and polypropylene fish farm tanks with a single plane of the side wall slope, i.e. in particular in fish farming during fish-harvesting, fish sorting or sale. Where there is a need for short-time storage of a larger quantity of fish or other animals related to fish farming and provision of relevant conditions for life, in particular a sufficient amount of oxygen. It will find application in the Czech Republic as well as in other countries of Central and Eastern Europe where fish farming on ponds is widely pursued. Nevertheless, this equipment may also be found interesting in the environment of developed fish farming in Northern America, or where applicable in a much less sophisticated fish farming pursued in Asia and Africa where oxygen deficit when handling fish or shellfish, considering the higher temperature and water quality, is problematic as well.

Overview of the Positions

1 aeration adapter with oxygenation

2 fish farm tank

3 first distributing aeration ring

3 second distributing aeration ring

4 distributing oxygenation ring

5 compressed air supply line

6 compressed oxygen supply line

7 fastening element of the aeration adapter with oxygenation

8 means for attaching onto the fish farm tank

9 system of supports

10 rubber tension rope

1 1 fish farm tank bottom

12 fish farm tank wall

13 bottom of the aeration adapter with oxygenation

14 shell of the aeration adapter with oxygenation

15 belt

16 aeration opening

17 oxygenation opening

Claims

1 . The aeration and oxygenation equipment intended in particular for fish farm tanks (2), characterized in that it consists of the aeration adapter (1 ) with oxygenation, the supply line (5) of compressed air and the supply line (6) of compressed oxygen connected to the aeration adapter (1 ) with oxygenation; the aeration adapter (1 ) with oxygenation has a shape corresponding to the inner surface of the fish farm tank (2) and is adapted to be put into the tank (2) and fitted with fastening elements (7) for attachment to the edge of the tank (2), and that the aeration adapter (1 ) with oxygenation consists of the bottom (13) with aeration openings (16) and with oxygenation openings (17) and of the shell (14) connected to the bottom (13) the shape of which is adjusted to sit on the inner surface of the tank (2), wherein under the bottom (13) at least one distributing aeration ring (3) with aeration pores is arranged and connected to the supply line (5) of compressed air and at least one distributing oxygenation ring (4) with oxygenation pores connected to the supply line (6) of compressed oxygen.

2. The aeration equipment according to claim 1 , characterized in that the supply line (5) of compressed air and/or the supply line (6) of compressed oxygen are arranged on the outer side of the shell (14).

3. The aeration equipment according to claim 1 , characterized in that the supply line (5) of compressed air and/or the supply line (6) of compressed oxygen are integrated in the shell (14).

4. The aeration equipment according to any of claims 1 through 3, characterized in that the shell (14) comprises three belts (15) arranged along 20 to 50% of the perimeter of the bottom (13) of the aeration adapter (1 ).

5. The aeration equipment according to any of claims 1 through 3, characterized in that the shell (14) is comprised of one solid belt (15) forming a cylinder or truncated cone arranged along the entire perimeter of the bottom (13) of the aeration adapter (1 ).

6. The aeration equipment according to any of claims 1 through 5, characterized in that the bottom (13) of the aeration adapter (1 ) with oxygenation is in the shape of a circle.

7. The aeration equipment according to any of claims 1 through 6, characterized in that the distributing aeration ring (3) is in the shape of a circle with aeration pores with the diameter ranging from 0.8 to 0.9 mm for the penetration of air into the aeration openings (16), the distributing oxygenation ring (4) is in the shape of a circle with oxygenation pores with the diameter of 0.05 up to 0.2 mm in the quantity of 10 pcs per 1 cm for the penetration of oxygen into the oxygenation openings (17) and are deployed above the bottom (1 1 ) of the fish farm tank (2).

8. The aeration equipment according to any of claims 1 through 7, characterized in that arranged under the circular bottom (13) are two distributing aeration rings (3, 3^') and one distributing oxygenation ring (4) with different diameters where the first distributing ring (3) has the diameter n, the second distributing ring (3^') has the diameter r₂ and the distributing oxygenation ring (4) has the diameter r₃, where n £ r₂ < r₃.

9. The aeration equipment according to any of claims 1 through 8, characterized in that the fastening elements (7) are created as a rim of the shell (14) to be bent over the edge of the fish farm tank (2) along its perimeter or at least in three points using rubber fabric or a rubber tape or rubber tension rope (10) to attach the aeration adapter (1 ) with oxygenation to the fish farm tank (2).

10. The aeration equipment according to any of claims 1 through 9, characterized in that the aeration adapter (1 ) with oxygenation is made of polypropylene or laminate or carbon fibre reinforced polymer.

1 1. The aeration equipment according to any of claims 1 through 10, characterized in that the bottom (13) of the aeration adapter (1 ) with oxygenation is reinforced by the system (9) of supports in the shape of radial ribs with the height of the ribs ranging from 2 to 6 cm, where the ribs are fitted with through openings for the passage of the distributing aeration ring (3, 3^') and the distributing oxygenation ring (4).