U.S. patent application number 09/775731 was filed with the patent office on 2002-08-08 for debris separating system for fish pens.
This patent application is currently assigned to Future Sea Technologies Inc.. Invention is credited to Brenton, Clayton Mearle.
Application Number | 20020104487 09/775731 |
Document ID | / |
Family ID | 25105319 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020104487 |
Kind Code |
A1 |
Brenton, Clayton Mearle |
August 8, 2002 |
Debris separating system for fish pens
Abstract
A debris separating system for separating debris in a fish tank
is formed by a standpipe extending up through the bottom of tank at
the center of tank and terminating in an open end. A cover covers
the opening and is spaced therefrom to provide an inlet opening
positioned above the bottom of the tank. A transition zone is
formed at the bottom of the tank surrounding the standpipe and a
debris outlet is provided from this zone through the bottom of the
tank for removal of debris separated in the transition zone.
Cleaned water from the transition zone flows up around the
standpipe, through the inlet opening and into the standpipe for
removal from the tank.
Inventors: |
Brenton, Clayton Mearle;
(Nanaimo, CA) |
Correspondence
Address: |
C.A. Rowley
51 Riverside Parkway
P.O. Box 59
Frankford
ON
K0K 2C0
CA
|
Assignee: |
Future Sea Technologies
Inc.
|
Family ID: |
25105319 |
Appl. No.: |
09/775731 |
Filed: |
February 5, 2001 |
Current U.S.
Class: |
119/223 |
Current CPC
Class: |
Y02A 40/826 20180101;
A01K 61/60 20170101; Y02A 40/81 20180101 |
Class at
Publication: |
119/223 |
International
Class: |
A01K 061/00 |
Claims
We claim:
1. A debris separating system for separating debris in a fish tank
having a substantially circular cross section and wherein incoming
water is pumped into the tank with momentum substantially tangent
to the periphery of said tank to cause said water to flow with a
circular motion from the top toward the bottom of said tank, said
tank having a bottom, said debris separating system comprising a
standpipe concentric with said tank and extending through said
bottom of said tank to a position below a surface of water in said
tank, said stand pipe having an open upper end forming an upper
opening spaced from said bottom of said tank, an expanded section
of said standpipe surrounding said open end, a cover concentric
with said open end and spaced above said open end to define an
inlet passage into said open upper end between said cover and said
expanded section of said standpipe, said cover a diameter greater
than said open upper end to shelter said open upper end from debris
that may fall from water above said open end and to disrupt a
vortex formed in at the center of the tank by said incoming
water.
2. A debris separating system as defined in claim 1 wherein the
ratio of the depth D of said open upper end of said standpipe from
said surface of said water in said tank to the depth d to said
bottom of said tank is between 0.7 and 0.9.
3. A debris separating system as defined in claim 1 further
comprises a plurality of circumferentially spaced vanes arranged
symmetrically around said inlet passage in spaced relation to said
open end and to direct flow into said open end
4. A debris separating system as defined in claim 2 further
comprises a plurality of circumferentially spaced vanes arranged
symmetrically around said inlet passage to direct flow into said
open end
5. A debris separating system as defined in claim 3 wherein vanes
have a pair of opposite faces along which said water flows into
said open end and wherein said faces are oriented at an angle of
between 35 and 50.degree. to a radius of said standpipe
6. A debris separating system as defined in claim 4 wherein said
vanes have a pair of opposite faces along which said water flows
into said open end and wherein said faces are oriented at an angle
of between 35 and 50.degree. to a radius of said standpipe
7. A debris separating system as defined in claim 1 wherein said
cover has a convex dome shape with its convex surface facing away
from said open upper end.
8. A debris separating system as defined in claim 3 wherein said
cover has a convex dome shape with its convex surface facing away
from said open upper end.
9. A debris separating system as defined in claim 4 wherein said
cover has a convex dome shape with its convex surface facing away
from said open upper end.
10. A debris separating system as defined in claim 7 wherein said
dome is substantially conical.
11. A debris separating system as defined in claim 8 wherein said
dome is substantially conical.
12. A debris separating system as defined in claim 9 wherein said
dome is substantially conical.
13. A debris separating system as defined in claim 8 further
comprising an inverted cone concentric with said open upper end
with its conical surface facing said open end, said inverted cone
having a diameter less than said diameter of said dome.
14. A debris separating system as defined in claim 9 further
comprising an inverted cone concentric with said open upper end
with its conical surface facing said open end, said inverted cone
having a diameter less than said diameter of said dome.
15. A debris separating system as defined in claim 10 further
comprising an inverted cone concentric with said open upper end
with its conical surface facing said open end, said inverted cone
having a diameter less than said diameter of said dome.
16. A debris separating system as defined in claim 1 wherein said
outlet system is positioned above a bottom of said tank and
relative to said tank to combine with the adjacent portions of said
bottom of said tank to define a transition zone surrounding said
standpipe
17. A debris separating system as defined in claim 2 wherein said
outlet system is positioned relative to said tank to combine with
the adjacent portions of said bottom of said tank to define a
transition zone surrounding said standpipe
18. A debris separating system as defined in claim 3 wherein said
outlet system is positioned relative to said tank to combine with
the adjacent portions of said bottom of said tank to define a
transition zone surrounding said standpipe
19. A debris separating system as defined in claim 4 wherein said
outlet system is positioned relative to said tank to combine with
the adjacent portions of said bottom of said tank to define a
transition zone surrounding said standpipe
20. A debris separating system as defined in claim 5 wherein said
outlet system is positioned relative to said tank to combine with
the adjacent portions of said bottom of said tank to define a
transition zone surrounding said standpipe
Description
FIELD OF INVENTION
[0001] The present invention relates to an improved system for
removal of debris from a fish pen.
BACKGROUND OF THE INVENTION
[0002] It is common practice for the commercial purposes to grow
aquatic organisms such as fish and the like in tanks or bag like
structures hereinafter referred to as fish tanks or pens. One of
the main problems of growing these aquatic organisms is the
disposal of sediment such as excrement and other debris that would
otherwise build in the bottom of the tank or to be released into
the surrounding waters and cause contamination detrimental to the
process or the surrounding environment.
[0003] There have been numerous proposals and applied systems for
cleaning aquaculture tanks many of which take the debris off from
the bottom of the tank. See for example U.S. Pat. Nos. 4,655,169
issued Apr. 7, 1987 to Paliola; 4,798,168 issued Jan. 17, 1989 to
Vadseth et al.; 5,593,574 issued Jan. 14, 1997 to VanToever;
5,636,595 issued Jun. 10, 1997 to Lunde et al.; and 6,093,320
issued Jul. 25, 2000 to White.
[0004] All of the systems described in the patents use water
movement to help to deliver the sediment to a sediment outlet, for
example rotating flow in circular tanks to sweep the sediment
toward the centre of the tank. U.S. Pat. No. 4,655,169 referred to
above describes a system wherein conical grooves are provided in
the bottom end of the tank and a circular flow is imparted into the
water in the tank to cause the debris that settles to the bottom of
the tank to be swept along the conical grooves into a collecting
chamber or sump at the center of the tank. This system obviously
relies on gravity for separation of the sediment from the water
i.e. the sediment falls by gravity to the bottom of the tank and
the thus concentrated debris is swept along the helical bottom
passages to a sump.
[0005] U.S. Pat. No. 4,798,169 injects fresh water substantially
tangentially adjacent to the top of the tank and imparts a
significant velocity to the water to cause it to flow around the
tank with sufficient velocity to cause the fish in the tank to
orient themselves relative to the current created by the circular
flow in the tank. A simple outlet is provided at the apex of the
tapered bottom of the tank and the debris is brought to this outlet
for removal from the tank by the circulating water.
[0006] U.S. Pat. No. 5,593,574 discloses a water treatment system
for fish tanks that includes a biofilter system that uses a spray
bar to distribute water over a bed of pellets. The treated water is
removed adjacent to but spaced above the bottom of the biofilter
tank through an outlet pipe having an inlet sheltered under a cone.
Debris is removed through a sump at the bottom of the biofilter
tank surrounding the outlet pipe.
[0007] U.S. Pat. No. 5,639,595 employs an annular chamber or sump
surrounding a main tank outlet defined by an upper deck spaced from
the bottom of the tank to provide a flow inlet extending around the
full circumference of the sump. The sump is frusta-conical tapering
towards a bottom end that is provided with a debris outlet adjacent
to the central or axial main outlet passage from the tank. Outlet
holes connect the sump with the main outlet passage at a position
well above the debris outlet in the bottom of the sump. Water
carrying debris flows into the chamber substantially radial around
the full periphery of the chamber and towards the bottom and then
flows back up and out through the outlet passages leading to the
main passage. Debris falling from the water entering the sump is
removed via the debris outlet. This system does not significantly
concentrate the sediment for removal.
[0008] U.S. Pat. No. 6,093,320 belonging to the same company as the
present invention teaches a cleaning system that employs a baffle
system and injectors for imparting tangential velocity to the water
entering the sump to separate the debris below the baffle and
remove it through a sump and the cleaned water that carried the
debris into the sump flows over the baffle and is released.
BRIEF DESCRIPTION OF THE PRESENT INVENTION
[0009] It is an object of the present invention to provide a debris
separating system that is easy to operate and employs the water
currents in the fish tank to deliver the debris to an outlet.
Broadly the present invention relates to a debris separating system
for separating debris in a fish tank having a substantially
circular cross section and wherein incoming water is pumped into
the tank with momentum substantially tangent to the periphery of
said tank to cause said water to flow with a circular motion from
the top toward the bottom of said tank, said tank having a bottom,
said debris separating system comprising a standpipe concentric
with said tank and extending through said bottom of said tank to a
position below a surface of water in said tank, said stand pipe
having an open upper end spaced from said bottom of said tank, and
expanded section of said standpipe surrounding said open end, a
cover concentric with said open end and spaced above said open end
to define an inlet passage into said open end between said expanded
section of said standpipe, said cover having a diameter greater
than said open upper end to shelter said open end from debris that
may fall from water above said open end and to disrupt a vortex
formed in said tank by said incoming water.
[0010] Preferably the ratio of the depth D of said open upper end
of said standpipe from said surface of said water in said tank to
the depth d to said bottom of said tank is between 0.7 and 0.9.
[0011] Preferably said debris separating system further comprises a
plurality of circumferentially spaced vanes arranged symmetrically
around said inlet passage.
[0012] Preferably, said vanes have a pair of opposite faces along
which said water flows into said open end and wherein said faces
are oriented at an angle of between 35 and 50 to a radius of said
standpipe.
[0013] Preferably said cover is a convex dome shape with its convex
surface facing away from said open upper end.
[0014] Preferably said dome is substantially conical.
[0015] Preferably said debris separating system further comprises
an inverted cone concentric with said open upper end with its
conical surface facing said open end, said inverted cone having a
diameter less than said diameter of said dome.
[0016] Preferably said outlet system combines with the adjacent
portions of said bottom of said tank to define a transition zone
surrounding said standpipe
[0017] Preferably a debris outlet is provided through said bottom
wall adjacent to said standpipe.
BRIEF DESCRIPTION OF THE DRAWINGS(S)
[0018] Further features, objects and advantages will be evident
from the following detailed description of the preferred
embodiments of the present invention taken in conjunction with the
accompanying drawings in which;
[0019] FIG. 1 is a schematic side elevation of fish tank
incorporating the debris separating system of the present invention
and showing the vertical flow pattern of the water in the tank.
[0020] FIG. 2 is a schematic side elevation of fish tank
incorporating the debris separating system of the present invention
and showing the horizontal flow pattern of the water in the
tank.
[0021] FIG. 3 is a cross section through the debris separating
system of the present invention.
[0022] FIG. 4 is a partial section with parts removed for clarity
on the line 4-4 of FIG. 3 showing the orientation of the vanes
relative to the direction of flow of the water entering the
standpipe.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention relates to a system for separating
debris which may include particles of fish waste, uneaten food and
the like which must be removed from the tank and disposed of is a
suitable manner.
[0024] FIG. 1 shows a fish tank 10 positioned in a body of water
(fresh or salt) the surface of which is indicated at L. The pen or
tank 10 is preferably circular in cross section and has a
centerline 12 and a convex bottom portion 14 that converges from
the outer peripheral wall 16 toward the centerline 12. Adjacent to
the top of the tank is a substantially tangential inlet 18 that is
oriented to direct fresh water moved by a suitable pump (not shown)
into the tank 10 and provide the water with momentum to flow around
the tank 10 as indicated by the arrow 20 in FIG. 2. The flow of the
water also has a downward component as indicated by the arrows 22
in FIG. 1. This downward component is reversed as indicated by the
arrow 24 above the debris separator system or unit 100 positioned
on the centerline 12 at the bottom of the tank 10 as will be
discussed below. This reversal of flow to the upward direction is
again reversed above the separator 100 and adjacent to the surface
of the water in the pen 10 to tend to flow back down as indicated
by the arrow 26. It will be apparent that the flow of water in the
pen is substantially symmetrical about the axis 12.
[0025] This circulation of the water around and above the unit 100
as indicated by the arrows 20, 22, 24 and 26 creates a transition
or quiescent zone 30 in volume extending in the area surrounding
the unit 100 from the bottom 14 and up to about flange 108 as will
be described below
[0026] As shown in FIG. 3 the unit 100 is composed of a standpipe
102 that has its axis concentric with the axis 12 and extends
through the bottom portion 14 and into the tank 10 to a position
spaced well below a surface L of the water in the tank 10.
[0027] The standpipe 102 has an upper or top opening 104 into the
standpipe 102. In the illustrated arrangement, the ratio (see FIG.
1) of depth D from the surface L to the level of the opening 104 to
the depth d to the bottom of the tank 10 from the surface L (D/d)
will never--be less than 0.5 and preferably will be in the range of
between 0.7 and 0.9. In a particular system with a tank 10 meters
deep, a standpipe height of 1.5 meters has been found satisfactory,
i.e. d=10 meters, D=8.5 meters, D/d=0.85.)
[0028] In the arrangement illustrated the diameter of the pipe 102
flares outward in frusta conical fashion as indicated at 106 to
provide an upper opening larger than the diameter of the pipe 102.
A substantially radial flange 108 surrounds the opening 104. It can
be seen that the overhang created by the cone 106 and flange 108
results in a requirement that flow from the bottom of the zone 30
adjacent to the standpipe 102 must reverse and flow back outward
i.e. away from the axis 12 and upward as indicated by the arrow 110
to reach the top inlet end of the standpipe 102.
[0029] Positioned above and spaced from the opening 104 and the
flange 108 is a cover 112 that is concentric with the axis of the
pipe 102 and concentric with the axis 12 of the tank 10. The cover
112 in the illustrated arrangement has a convex surface facing away
from the opening 104. The cover 112 has a diameter greater than
that of the opening 104 and preferably greater than the outside
diameter of the flange 108 to protect the opening 104 from
receiving debris falling from water above the unit 100. The dome
112 is preferably a cone shape and aids in diverting debris from
the top of the cover and in directing the flow to make its first
reversal as indicated by the arrow 24, hence disrupting any strong
vortex action in the center of the tank 10.
[0030] A plurality of circumferentially spaced vanes 114 extend
between the flange 108 and the cover 112 and help to support the
cover in fixed spaced relationship to the opening 104. A tubular
support frame 119 is located between flange 108 and the cover 112
and provides the majority of the support for the cover 112. The
vanes 114 are uniformly spaced i.e. symmetrically positioned around
the periphery of the opening 104 with their side faces 115 oriented
to interfere slightly with the flow and divert it into the opening
104 i.e. the faces 115 are substantially parallel to the direction
of water flow (as represented by the arrows 117) as the water flows
past the vanes 114 and into the pipe 102 i.e. the vanes function to
direct the flow of water into the opening 104 as indicated in FIG.
4 without providing an major impedance to the flow. In a preferred
arrangement the angle .alpha.0 of sides 115 of the vanes 114 to a
radius r of the pipe 102 is preferably in the range of 35 to
50.degree. and will be in part determined by the velocity and flow
of the water into and out of the tank 10 which is also influenced
by the inside diameter of the standpipe 102 and the height H of the
spacing between the flange 108 and the dome 112 which in part
defines the size of the circumferentially extending inlet 116
opening leading to the pipe 102. The vanes 114 are preferably
widely circumferentially spaced for example with a flange 108
having an outside diameter of about 3 meters 4 vanes symmetrically
positioned around the pipe 102 have been found to be satisfactory
(I thought that on the Q-Trap that we built, 108 was 3 meters in
diameter).
[0031] In one particular realization of the invention in a tank of
about 12 meters in diameter in diameter and a volume of about 875
cubic meters and with an incoming water flow rate of between 20,000
to 60,000 liters/minute the standpipe 102 had an inside diameter of
about 1200 millimeters (mm), flared out to about 1950 mm in the
flared section 106 and the outside diameter of the flange 108 was
about 3000 mm. 4 symmetrically spaced vanes were used. Each of the
vanes 114 had a thickness of 6 mm, a length measured in the
direction of flow of about 400 mm and a height (i.e. height H) of
about 1000 mm. The end facing outward was filleted at its side
edges, but remained essentially blunt. The dimension may be changed
to accommodate different size pens and different flow rates.
[0032] As above described the circumferentially extending inlet 116
opening though which the water flows to reach the opening 104 is
formed between the adjacent surfaces of the cover 112 and the
flange 108 and extends from the outer edge of the flange 108 to the
inner edge of flange 108 where the flange 108 joins with the frusta
conical flare 106. Across this inlet opening 116 adjacent to the
inner periphery of the flange 108 i.e. inside (or outside if
desired) of the vanes 114 is a screen 118 that extends around the
inner periphery of the inlet opening 116 to screen any water
entering through the inlet opening 116. The screen 118 is attached
to the tubular support structure 119 and functions primarily to
stop fish from escaping and thus may have corresponding sized
holes.
[0033] It is preferred to provide a cone 120 inverted relative to
and concentric with the cover or dome 112 to direct flow entering
through the inlet 116 into the opening 104 and thus the standpipe
102.
[0034] Debris separated in the transition zone 30 is removed from
the tank or pen 10 via the debris outlet 122 (see FIG. 3).
[0035] In operation fresh water enters the tank 10 via inlet 18 and
flows in the tank as indicated by the arrows 20, 22, 24, 26 and
110. The unit 100 impedes the flow adjacent to the center of the
bottom of the pen 10 and creates the transition zone 30 surrounding
the unit 100. Debris moves down the tank generally adjacent to the
wall 16 and then along the wall 14 into the transition zone 30 and
the debris is dropped from the water in the zone 30. The cleaned
water then flows as indicated by the arrows 110 up along the
outside of the unit 100 until it reaches the inlet 116 where it
passes through the screen 118 and then through the opening 104 into
the standpipe 102 and back into the surrounding waters. The debris
separated in the zone 30 moves to the outlet 122 alas is ejected
from the tank and directed to a suitable disposal cite.
[0036] Having described the invention, modifications will be
evident to those skilled in the art without departing from the
scope of the invention as defined in the appended claims.
* * * * *