GB2241857A - Screen for fish tank outlet - Google Patents
Screen for fish tank outlet Download PDFInfo
- Publication number
- GB2241857A GB2241857A GB9003183A GB9003183A GB2241857A GB 2241857 A GB2241857 A GB 2241857A GB 9003183 A GB9003183 A GB 9003183A GB 9003183 A GB9003183 A GB 9003183A GB 2241857 A GB2241857 A GB 2241857A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tank
- screen
- cylindrical
- fish
- outlet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 241000251468 Actinopterygii Species 0.000 title claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 49
- 241001465754 Metazoa Species 0.000 claims abstract description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims abstract description 4
- 239000010935 stainless steel Substances 0.000 claims 1
- 239000002245 particle Substances 0.000 abstract description 19
- 235000019688 fish Nutrition 0.000 description 22
- 210000003608 fece Anatomy 0.000 description 10
- 235000013305 food Nutrition 0.000 description 8
- 238000000465 moulding Methods 0.000 description 8
- 239000008188 pellet Substances 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 3
- 241000972773 Aulopiformes Species 0.000 description 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000004567 concrete Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000011152 fibreglass Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 238000010926 purge Methods 0.000 description 2
- 235000019515 salmon Nutrition 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- QDHHCQZDFGDHMP-UHFFFAOYSA-N Chloramine Chemical compound ClN QDHHCQZDFGDHMP-UHFFFAOYSA-N 0.000 description 1
- 241000277331 Salmonidae Species 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000009313 farming Methods 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 210000002816 gill Anatomy 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000005802 health problem Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000010871 livestock manure Substances 0.000 description 1
- FDZZZRQASAIRJF-UHFFFAOYSA-M malachite green Chemical compound [Cl-].C1=CC(N(C)C)=CC=C1C(C=1C=CC=CC=1)=C1C=CC(=[N+](C)C)C=C1 FDZZZRQASAIRJF-UHFFFAOYSA-M 0.000 description 1
- 229940107698 malachite green Drugs 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000013521 mastic Substances 0.000 description 1
- 238000002483 medication Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000009372 pisciculture Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000028327 secretion Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000002485 urinary effect Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K63/00—Receptacles for live fish, e.g. aquaria; Terraria
- A01K63/04—Arrangements for treating water specially adapted to receptacles for live fish
- A01K63/042—Introducing gases into the water, e.g. aerators, air pumps
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K63/00—Receptacles for live fish, e.g. aquaria; Terraria
- A01K63/10—Cleaning bottoms or walls of ponds or receptacles
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K61/00—Culture of aquatic animals
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K63/00—Receptacles for live fish, e.g. aquaria; Terraria
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/80—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in fisheries management
- Y02A40/81—Aquaculture, e.g. of fish
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Environmental Sciences (AREA)
- Marine Sciences & Fisheries (AREA)
- Animal Husbandry (AREA)
- Biodiversity & Conservation Biology (AREA)
- Zoology (AREA)
- Farming Of Fish And Shellfish (AREA)
Abstract
A cylindrical screen prevents the escape of fish or other aquatic animals into an outlet (34) of a tank and comprises a sheet of welded stainless steel wire mesh (37) rolled into a tube with its longitudinal edges secured together. Lower and upper sections (38 and 39) of cylindrical piping are fitted into the ends of the wire mesh tube (37) and are held in position by contractile clips. The lower section (38) is a push fit into the tank outlet (34) whilst the upper section (30) stiffens the upper end of the wire mesh tube and extends to above the maximum water level (19) in the tank. The upper end of the lower section (38) is at a level (X-X) above the tank bottom (14) to provide a dead zone for the deposit of particles to be sucked through a separate drainage system. <IMAGE>
Description
FISH TANK
The present invention relates to a tank for raising fish or other animals. Various forms of tank are in use in the fish fanning industry and these include cylindrical tanks having a water inlet over the tank side and a control drain whereby water can pass through the tank at a rate adjusted by a central valve regulating the water inlet. The rate of water flow through the tank must, of course, be adequate to supply the oxygen requireents of the fish and to dilute the urinary secretions of the fish to a tolerable level. The depth of water in the tank i5 usually regulated by a depth control device, or launder, positioned outside the tank.The water inlet is usually arranged so that the kinetic energy of the inflowing water can be vectored to control the rotational speed of the water in the tank to a value suitable for the size of fish.
The fish will be fed a carefully calculated weight of feed each day usually in the form of dried pellets, the daily ration being divided into a series of smaller feeds at intervals during the day. when farming fish, it is coWn practice to provide a slight surplus of feed to ensure that there will be sufficient for the smaller fish in the tank and this inevitably means that excess feed accumulates on the tank botcrr. Fish, such as salmon, can be put off their feod by diverse ambient factors such as falling water temperature, falling levels of oxygen saturation (typically during the early afternoon), windspeed and temperature, and randcun shadows such as a bird flying over the tank.For this reason some feeds are not taken and further excess food pellets gather on the tank bottom. Salmon and Trout prefer to eat their food as it floats past thfflm and any pellets reaching the tank bottom are usually ignored.
As the feed pellets rest on the tank bottcxm they slowly soften into much smaller particles which tend to rertain in the boundary layer at the bottom of the tank. The rotational speed of the water and the central drain tend to move these smaller particles towards the centre of the tank where they tend to lie in a rirg around the central drain. In addition to the surplus feed, sane of the fish faeces also sink to the bottam to join the excess food.As the fish faeces are less dense than the feed pellets, a proportion of than are swept into the central drain before they can fall into the tank bottom.
As a consequence of the above, the fish farmer finds himself between two conflicting problems as, on the one hand, he cannot tolerate an accumulation of faeces and excess food in the tank and, on the other hand, he would prefer not to discharge the accumulated faeces and excess food back into the water supply. At present the fish faliner has no choice but to keep his fish healthy and it is common practice for such tanks to be "purged" at least once (usually twice) each day. Such purging involves rapidly draining water from the tank, typically by opening the depth control device, and this causes a forced vortex at the centre of the tank which stirs up all of the accumulated excess food and faeces so that it will be flushed out of the tank.This process involves discharging typically 20% - 50% of the water in the tank and results in a large volute of filthy water being discharged, usually into the wateoourse or into a settlement tank. Additionally the fish are subjected to the shock of a sudden increase in the water speed which can pull smaller fish onto the screen over the centre drain, and the experience of swinnixlg through the suspended particles which can stick in their gills and cause health problems,
According to the invention a cylindrical tank is provided with two drainage systems, the first drainage system being positioned at the central axis of the tank and incorporating a depth control device for regulating the depth of water in the tank, the second drainage system being positioned in the bottom of the tank around the first drainage system to suck particles from the bottom of the tank.
The second drainage system may function all the time provided the flow of water used is less than the flow of water into the tank whereby the bottom of the tank is continuously cleaned. This feature is useful when the discharge of particles into a watercourse is not a potential problem, However the second drainage system is preferably connected through a control valve to a foul drain. In this manner the control valve may normally be kept closed, but can be opened at intervals to suck accumulated particles from the tank bottom into the foul drain.
Preferably the connection between the second drainage system and the foul drain inCorpOrates an anti-syphoning device, Preferably the connection betweeen the second drainage system and the foul drain is arranged so that it can only drain the tank to a predetermined safe level if the control valve is left open.
The second drainage system preferably defines a suction means pointing outwardly along the tank bottom. Preferably the suction nests is an annular orifice defined around a central opening in the tank bottom leading into the first drainage -system. Alternatively the suction means may be an annular array of orifices defined around the central opening.
Preferably a ring-shaped chamber may be provided in the tank bottom around the first drainage system alzd interconnecting U suction means to the remainder of the second drainage system. The latter preferably includes a drainage duct connected tangentially to the ring-shaped chamber whereby water and particles sucked through the suction means will swirl around the ring-shaped charriber into this drainage duct. Preferably the drainage duct is connected to the ring-shaped chamber so that the direction of the swirl will be the same as the direction of water rotation in the tank. Preferably the cross-sectional area of the drainage duct is similar to the cross-sectional area of the suction means.
The first drainage system preferably includes a tublular fishexclusion screen arranged vertically about the central axis of the tank and connected by a tubular section to the remainder of the first drainage system. The tubular section is preferably arranged to fit into a socket connection which is positioned in the centre of the rirg-shaped chamber
but is connected to Ule remainder of the first drainage system.
The tubular section is preferably of such a length that its upper end
is spaced above the bottom of the tank to leave a shallow dead zone over the tank bottom to facilitate settling of the particles. Preferably the bottom of the tank is formed so that it slopes gently downwards towards the centre.
The first and second drainage systems may be defined by a unit having a flange compatible with existing tanks which may thereby be modified to provide the fedtures of the present invention.
The invention is now described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a vertical cross-sectional view of a known type of
cylindrical tank used for fish farming;
Figure 2 is a plan view of Figure 1;
Figure 3 is a vertical cross-section (to a larger scale) illustrating
how the tank of Figures 1 and 2 can be modified in accordance with
the present invention;
Figure 4 is a plain view of Figure 3 but with the plate and centre
screen omitted, and
Figure 5 is a vertical cross-section similar to Figure 1 but showing
part of a much larger tank constructed in accordance with the present Invention.
With refernce to Figures 1 and 2 a conventional glass-reinforced plastic cylindrical tank canprises two semicylindrical moulding 10, a screen plate 11 and a centre moulding 12. The semi-cylindrical rsuldings 10 have unshown flanges by which they are bolted together using an intervening sealing strip, and define a depending cylindrical flange 13 to the centre of the tank bottom 14. The centre moulding 12 is trapped, during assembly of the semi-cylindrical mouldings 10, inside the cylindrical flange i3 with intervening sealing stripes, and is bolted in the correct position whereby the screen plate 11 can be located above, as shown, and sealed in position using mastic.
The screen plate 11 is foxed with four accurate apertures over which perforated aluminirnutn screens 15 are rivetted as shown in Figure 2. At its centre, the screen plate 11 has a cylindrical flanged opening which receives a cylindrical centre screen 16 formed from a rolled perforated aluminimum sheet with a rolled flange 17 to limit its penetration into the centre moulding 12. In this manner the top of the centre screen 16 is positioned just above the water level 18 but below the tank rim.
The centre moulding 12 is formed integral with a length of polyvinylchloride piping 19 leading to a depth control device which is indicated generally by arrow 20.
The depth control device 20 comprises inner and outer concentric tubes 21 and 22 respectively, and an wring seal 23 engaged by the lc r end of the inner tube 21. In this manner water discharged through the pipe 19 is constrained by the seal 23 to flow upwards between the tubes 21 and 22 until if flows over the upper end of the inner tube 21 and falls, as indicated by arrow 24, into a tubular sump 25 set in concrete. From the sump 25, the discharge water flows into a drainage channel 26 which leads back to the river or lake serving as the water supply either directly or via a very large setttlement tank.
The size of the perforations in the screens 15 and the tubular centre screen 16 chosen to exclude the passage of fish into the central drain defined by the lToulditB 12,
The water supply is fran a distribution pipe 27 and a stand pipe 2s, through a control valve 29, to a water inlet 30 which extends over the tank rim. The angle of the water inlet 30 can be adjusted to alter the horizontal vector of the driving force exerted by the inlet water on the tank contents.
Excess food pellets sink to the tank bottom 14 where they slowly soften the much smaller particles which tend to remain in the boundary layer and the bottom of the tank. xe to the large flow area through the screens 15 and the centre screen 16, canpared with that of the piping 19, the velocity of flow through them is generally small and is insufficient to suck particles fran the bottom of the tank. Indeed particles tend to form a ring around the centre screen 16 and to block the perforations in the screens 15. If left for several ours, particles soon start to block the perforations in the lower part of the centre screen 16 as well, due to the very low pressure gradient across it.Indeed the pressure gradient is only the very tiny difference between the water level 18 and the level of the water flowing over the upper end of the tube 21.
To purge the tank of these accumulated particles, the inner tube 21 of the depth control device 20 is pulled upwards by its handle 31 until its lower end disengages the seal 23, thereby suddenly applying the full head between the water level 18 and the bottom of the depth control device 20 across the screens 15 and the centre screen 16. This generates a very strong vertical forced vortex which stirs up the whole contents of
the tank and, with a three metre diameter tank, about 50% of the water content must be discharged to evacuate the particles which are stirred up.
Also, due to the very low velocities through the centre screen, water tends to be drawn frcm all levels of the tank and a proportion of the fish faeces are drawn out of the tank before they can reach the bottom - this helps to keep the tank cleaner than otherwise but makes subsequent separation of these faeces dificult.
With reference to Figures 3 and 4, the centre moulding 12 shown in
Figure 1 is replaced by a unit 32 having a flange 33 which is carpatible with the flange 13 so that existing tanks of the type shown in Figures 1 and 2 can be modified by the simple insertion of the unit 32.
Unit 32 is forired from a standard polyvinylchloride pipe bend 34 incorporated into a glass reinforced plastics moulding which defines the flange 33, a ring-shaped chamber 35 and a tangential drainage duct 36.
The centre screen 16 shown in Figure 1 and 2 is replaced by a new design of fish-excluding screen comprising a roll of welded stainless steel wire mesh 37 of which the longitudinal edges are over-lapped and clipped together. The ends of this tube of stainless steel wire resh are fitted over lower and upper sections of piping 38 and 39 (the upper section can be seen in Figure 5) and are held in position using contractile clips 40, The centre screen 16 is thus a simple push fit into the pipe bend 34 of which the associated sealing ring secures the centre screen 16 in position. Houwever, from trials I have carried out, the sealing ring can be omitted to leave the centre screen 16 merely sitting in the pipe bend.
An annular plate 41 fits around the lower pipe 38 ot the centre screen 16 and xests on the tank bottom 14. An annular series of narrow ridges 42 hold the lower surface of the plate 41 clean of the tank bottcm and define an annular array of orifices constituting a suction means pointing outwardly along the tank bottom. The plate 41 is preferably made of steel with the ridges 42 formed of welded steel strip, the whole construction being either galvanised or powder coated. The crosssectional flow area Of the annular array of orifices is approximately the same as the cross-sectional flow area of the tangential drainage duct 36.
If desired, the annular plate 41 may be fixed to the tank bottom using adhesive or screws through the ridges 42. The cross-sections of each of the orifices is chosen so that none of the fish to be placed in the tank can escape through them.
In operation the unit 32 provides two separate drainage systems frcm the tank. The first drainage system takes water through the centre screen 37, 38 39 and the pipe bend 34 into a conventional depth control device such as that described with reference to Figures 1 and 2. The second drainage system sucks primarily along the tank bottom 14 as indicated by arrow 43, the water and suspended particles passing into the ring-shaped chamber 35 and then swirling through the tangential duct 36 into a foul drain as will be shortly described with reference to Figure S It should be noted that water is also sucked through the slight clearance between the annular plate 41 and the lower pipe 38, as indicated by arrows 44, and this keeps the top of the annular plate 41 clear of paxticles.
Also it should be noted from Figure 3 that the upper end o the pipe 38 is spaced above the tank bottom 14 to leave a dead zone below the line XXo In this manner the water leaving the tank through the first drainage system 37, 34 is drawn primarily frcgn above the dead zore ?(X so that all
particles falling below the line XX tend to gather on the tank bottom 14,
Figure 5 illustrates a much larger tank which has been built to test
the principles of the present invention.The tank is of about eight
metres diameter and is constructed =rcm glass-coated steel sheets 45 with
upper and lower reinforcing rings all tied to a reinforced concrete base
48 defining the tank floor 14 so that it slopes gently towards the centre
screen 37.
The tank of Figure 5 operates in the same manner as the arrangement
shown in Figures 3 and 4 but the unit 32 is replaced by a galvanised steel
fabrication 49 which is cast into the concrete floor to define the ring
shaped chamber 35 and a true top surface for the annular plate 41 to bear
against.
The tangential drainage duct 36 leads through a oontrol valve 50 to
a foul drain 51, the pipework downstream of the control valve 50 having an opening 52 cut in its upper surface to constitute an anti-syphoning
device. In operation, the control valve 50 is normally kept closed but
is opened twice a day to suck the particles that have accumulated on the
tank floor 14 into the foul drain 51. When the control valve 50 is
opened, the head between the water level and the line YY is applied across
the array of orifices under the annular plate 41 to scour particles from
the tank bottom 14. With the tank shown in Figure 5, I have found that
the floor is completely purged by opening the control valve 50 for less
than one minute, twice a day.Indeed, when the valve 50 is opened, the
nature of the discharge can be viesred through the openers 52 and c npriseS the clean water lying in the pipe 36 and the ring-shaped chamber 35,
followed by a short but very concentrated slug of ìlt}zy water, and then by clean water showing that the tank has been fully purged.
Thus, the tank construction taught by the present invention enables tanks to be thoroughly purged with only a tiny percentage of the tank contents (less than 1%), collects a larger proportion of the faeces by utilising a dead zone at the tank bottom, and discharges the faeces and excess food into a separate drainage system. Hereby facilitating its subsequent treatment. This of course means that the water discharged through the
level control is much cleaner than hitherto and obviates any need for
large settlement tanks.Due to the small volumes discharged for very small periods into the foul drain 51, the processing of the effluent is facilitated as it can be collected in a smaller settling tank, similar to a septic tank, the sludge being recovered from time to time by conventional farm manure - spreading equipment for use as fertiliser.
Fish farms use various medications to treat their fish, for instance malachite green, formalin and chloramine -T, and these are usually discharged into the water course. With the equipment described, the valve 50 can be left open during treatment hereby diverting the medicated water into the foul drain 51.
If provision is made for diverting water from the valve 50 to the normal drainage channel 26, or other water course than the foul drain 51, the second drainage system can be used to hold the tank water level at YY whilst the fish are being caught.
Claims (10)
1. h cylindrical screen, for use in preventing tl.e escape of
fish or other aquatic animals into an outlet from a tannic, comprising a sheet of welded stainless steel ire mesh
rolled into a tube with the longitudinal edges of the sheet
being secured together.
2. A cylindrical screen, according to Claim 1, in Which the
longitudinal edges of the sheet are over-lapped before being
secured together.
3. A cylindrical screen, according to Claim 2, in which the
over-lapped edges are secured together by clips.
4. A cylindrical screen, according to any preceding claim, in .rllich one end of the wire mesh tube is secured to a section
of cylindrical piping of substantially similar diameter for
connection to the outlet.
5. A cylindrical screen, according to Claim L, in which the end
of the section of cylindrical piping adjacent the loire mesh
tube is arranged to be above the level of the tank bottom
when the screen is connected to the outlet.
o. A cylindrical Leen, according to any preceding claim, in
which the other end of the lsire mesh tube is secured to a
section of cylindrical piping of substantially similar diameter.
. A cylindrical screen, according to Claim 5, in which the length
of the screen is such that the upper end of the screen vill trill extend above the maximum water level when the screen is connected to the outlet.
8. A cylindrical screen, according to any of Claims 4 to 7, in
which the or each section of the cylindrical pipe is a close
fit within the respective end of the wire mesh tube.
9. A cylindrical screen, according to Claim 8, in which the
or each section of the cylindrical pipe is secured to its
respective end of the loire mesh tube by a respective
contractile clip.
10. A cylindrical screen, for use in preventing the escape of
fish or other aquatic animals into an outlet from a tank,
substantially as described herein with reference to Figures
3 and 5 of the accompanying drawings.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9003183A GB2241857A (en) | 1990-02-13 | 1990-02-13 | Screen for fish tank outlet |
| GB9103068A GB2242140B (en) | 1990-02-13 | 1991-02-13 | Tank for separating solids from water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9003183A GB2241857A (en) | 1990-02-13 | 1990-02-13 | Screen for fish tank outlet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9003183D0 GB9003183D0 (en) | 1990-04-11 |
| GB2241857A true GB2241857A (en) | 1991-09-18 |
Family
ID=10670877
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9003183A Withdrawn GB2241857A (en) | 1990-02-13 | 1990-02-13 | Screen for fish tank outlet |
| GB9103068A Expired - Fee Related GB2242140B (en) | 1990-02-13 | 1991-02-13 | Tank for separating solids from water |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9103068A Expired - Fee Related GB2242140B (en) | 1990-02-13 | 1991-02-13 | Tank for separating solids from water |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB2241857A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993023994A1 (en) * | 1992-06-01 | 1993-12-09 | Sinvent As | Particle trap |
| US6524028B2 (en) * | 2001-03-07 | 2003-02-25 | Farmers Irrigation District | Fish safe screened water diversion apparatus |
| US6726404B2 (en) * | 2002-08-20 | 2004-04-27 | The United States Of America As Represented By The Secretary Of The Army | Device and method for simulating natural cues so that waterborne fauna avoid contacting manmade barriers |
| CN102893944A (en) * | 2012-10-25 | 2013-01-30 | 中国水产科学研究院黄海水产研究所 | Aquaculture system discharging sewage automatically |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3077069B2 (en) * | 1991-12-27 | 2000-08-14 | 恩納村漁業協同組合 | Method and apparatus for culturing aquatic products at sea |
| NO175341C (en) * | 1992-07-20 | 1994-10-05 | Geir L Kjersem | Method of supplying water to a closed cage, forming a closed cage and using the cage to practice the method |
| CN101642073B (en) * | 2009-06-16 | 2011-10-05 | 烟台泰华海珍品有限公司 | Solid-liquid separating device of recycled water aquiculture pond |
| CN102939930B (en) * | 2012-11-27 | 2015-06-24 | 广东海洋大学 | Adjustable thee-channel round circulating water culture pond |
| NO20171340A1 (en) * | 2017-08-11 | 2019-02-12 | Sterner As | FARMING DEVICE |
| CN109042404A (en) * | 2018-08-19 | 2018-12-21 | 覃建忠 | A kind of porous tube body anti-escape for fish and preparation method thereof |
| NO345849B1 (en) * | 2020-05-04 | 2021-09-06 | Nekkar As | Outlet system for an aquaculture cage |
| NO20221285A1 (en) * | 2022-11-30 | 2024-05-31 | Alfa Laval Corp Ab | Fish Farming Enclosure |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB570851A (en) * | 1943-07-16 | 1945-07-25 | Blackburn Aircraft Ltd | Improvements in and relating to ice-guards for air intake systems of aircraft |
| GB578829A (en) * | 1945-01-09 | 1946-07-12 | Westwood Rim & Patents Ltd | Improvements relating to filters |
| GB585486A (en) * | 1944-10-31 | 1947-02-07 | F W Brackett & Company Ltd | Water screening surfaces |
| US4141318A (en) * | 1977-01-05 | 1979-02-27 | Union Carbide Corporation | Fish culture tank |
| GB1594831A (en) * | 1978-02-23 | 1981-08-05 | Goodson M G | Aquaculture system |
-
1990
- 1990-02-13 GB GB9003183A patent/GB2241857A/en not_active Withdrawn
-
1991
- 1991-02-13 GB GB9103068A patent/GB2242140B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB570851A (en) * | 1943-07-16 | 1945-07-25 | Blackburn Aircraft Ltd | Improvements in and relating to ice-guards for air intake systems of aircraft |
| GB585486A (en) * | 1944-10-31 | 1947-02-07 | F W Brackett & Company Ltd | Water screening surfaces |
| GB578829A (en) * | 1945-01-09 | 1946-07-12 | Westwood Rim & Patents Ltd | Improvements relating to filters |
| US4141318A (en) * | 1977-01-05 | 1979-02-27 | Union Carbide Corporation | Fish culture tank |
| GB1594831A (en) * | 1978-02-23 | 1981-08-05 | Goodson M G | Aquaculture system |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993023994A1 (en) * | 1992-06-01 | 1993-12-09 | Sinvent As | Particle trap |
| US6964541B2 (en) * | 2000-03-07 | 2005-11-15 | Farmers Irrigation District | Fish safe screened water diversion apparatus |
| US6524028B2 (en) * | 2001-03-07 | 2003-02-25 | Farmers Irrigation District | Fish safe screened water diversion apparatus |
| US6726404B2 (en) * | 2002-08-20 | 2004-04-27 | The United States Of America As Represented By The Secretary Of The Army | Device and method for simulating natural cues so that waterborne fauna avoid contacting manmade barriers |
| CN102893944A (en) * | 2012-10-25 | 2013-01-30 | 中国水产科学研究院黄海水产研究所 | Aquaculture system discharging sewage automatically |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9103068D0 (en) | 1991-03-27 |
| GB2242140A (en) | 1991-09-25 |
| GB2242140B (en) | 1994-01-26 |
| GB9003183D0 (en) | 1990-04-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |