METHOD AND AN APPARATUS FOR CLEANING THE NET BAGS OF BREEDING ENCLOSURES

METHODE POUR NETTOYER LES FILETS DES BASSINS DE PISCICULTURE

English Abstract

A method and an apparatus for cleaning the net bag of
breeding enclosures.
Abstract of the disclosure
An apparatus for cleaning the net bag for breeding enclosures
seines, and the like comprising a rotatable driven drum,
known per se, with an insert opening for the net bag and
radial inward projecting ridges, as well as feeding and
outlet means for washing and rinsing water. Said inlet means
for water are designed for continuous supply of water during
the entire period of operation, and outlet means are con-
tinuously open during the entire period of operation. Said
inlet means for water consist of axially directed openings or
nozzles which may be arranged in a cross-shaped pattern with
their point of intersection in the center of said drum. Said
outlet means consist of a number of axial open slots in the
drum shell. The water pressure in and the area of said inlet
openings are adapted to the area of outlets in such a manner
that the drum is approximately free for water during oper-
ation. The height of each ridge constitutes at least 10% of
the drum diameter.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed, are defined as
follows:
1. The method of cleaning accumulations of algae,
seaweed, mussels and other growth from the mesh threads of
a large, wet and heavy net bag that has been used as a
breeding enclosure moored in an immersed state in a body of
water forming a portion of a fish breeding plant,
comprising the steps of releasing the net bag from the net
bag mooring, removing the net bag with the accumulated
growth thereon from said body of water and placing the
entire bag within a rotatable drum, the drum being mounted
for rotation about a horizontal axis and having a plurality
of spaced outlet openings therein for the egress of said
accumulations from the interior of said drum, and the
interior of the drum also being provided with a plurality
of spaced ridges that extend substantially radially toward
the center of said drum with each such ridge having a
radial length that is at least 10% of the internal diameter
of the drum, continually rotating said drum in a single
direction to cause said ridges to regularly lift said net
bag from the bottom to the top of the drum whereafter said
net bag drops under the influence of gravity back to the
bottom of the drum, continually spraying wash water under
pressure, through water inlet openings in the drum, into
the interior of said drum as the drum is rotated and as
said net bag is lifted and dropped therein to cause
portions of said accumulated growth to be knocked off of
the mesh threads of the net bag by the combined action of
the wash water spray and the impact of said net bag against
the spaced ridges and interior walls of the drum, said wash
water being sprayed under pressure into the interior of
said drum from a side wall of the drum in a plurality of
spaced water jets each of which is directed generally
parallel to the axis of rotation of the drum, continually
draining the wash water and said portions of said
accumulated growth for the interior of said drum via said

openings during the continued spraying of said wash water
and the continued rotation of said drum until said net bag
is substantially free of all said accumulated growth, and
so correlating the pressure of said sprayed water and the
size of said water inlet openings to the area of said
outlet openings that the interior of said drum remains
substantially free of water build-up during the cleaning of
said net bag.
2. The method of claim 1 wherein said plurality of water
jets are arranged in a cross-shaped patterm.

Description

~ 2~756'~
_ A method and an apparatus for cleaning the net bagæ of
The present lnventlon relates to a method and a devlce for
cleanln~ ~he net bags of ~reedlng enclosures, or the llke.
Most fish breed~ng plants for fi6h for consumptlon, today use
breedlng enclo6ures wlth a net b~g lmmeraed ln the water in a
fJord or a ~hielded area where there l~ sufflclent current to
ens~re replacement of water. The net ba~s are steadlly
l~mersed in water, and pelaglc blue mussel fry adhere to the
mesh threads, and then clusters of mussel~ develop rapldly on
the bag. E6peclally due to the large supply of nutrimen~s
fed to the watcr when the flsh ln said enelosures 1B fed,
there ~ill be ~trong growkh of algae, ~reen seQweed, ~nd the
llke ln said net ba~. Thls will clog the net bag so that
free supply of water throu~h the meshes is reduced, ~nd the
result is ~hat 8~id ~et bags must often be taken ashore for
cleaning. Today, thls ls c~rried out by liftlng the bag step
by step by the aid o~ a crane and washing lt down by the ~id
of hlgh pressure Jets, one area at a tlme. Th~s 18 a ~lme
consuming as well as labour consumlng operatlon, usually
taklng from 5 ~o 8 hours with ~everal persons participating
ln the task. Such clean~ng of the net bags i~or breedlng
enclo~ures alone constltutes between 40 ~nd 50% of the work
at ~ fish breeding plant. Obviously, this i6 of ~reat
lmportance ~o the economy ~f ~ plant. Untll no~ the
fin~ncial situatlon ln this lndustry was good enough not to
make improvement of efficiency a must, but ln the fu~ure more
keen competition ls to be expected from other countr~es, and
lt will then be necsssary to reduce the need for ~anpower,
especially in a high cost country like Norway.
First an~ foremo~t, it ls ~n obJect of the inventlon to
provide a method for less e~pensive ~nd more rapld cleanlng
3~ of the net bag of ~reedlng enclosures.
,......

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No app~ratus for cleaning ~et ba~ for breedlng enclo~ure~
were previously propo~ed, and lt 1~ thus, another subJect of
the lnven~ion to provlde suCh an ~pparatus which can auto-
matlcally clean a net bag ln the cour~e of a i`ractlon of the
r. tlme it takes with the method previously used.
According to the inventlon this is achiev~d by a me~hod that
ls characterl~ed by the fact t;~at the net bag, released from
buoyancy bodles and moorln~, ls lntroduoed into a rotatable
;) driven drum provlded with a~ially extendlng ridges facing
lnward, that sa1 d net bag 18 washed by the ald of pressurlzed
water continuously sprayed through nozzles in the internal
drum wall, and that water ~nd washed off matter is during the
entlre washing oper~tlon dralned of~ through openlng in said
drum,
The apparatus accordlng to the lnvention i~ characterlzed by
the ~act that lt comprlses a rotatable driven drum, known per
se, and having an inlst opening ~or the net bag and radlally
proJectlng rldges, QS well as ~upply and outlet mPans for
washing water, sald water ~upply means being deslgned ~or
continuous supply of water durin~ the entlre operatlng
period, and that said outlet means are continuousl~r open
during the entlre operating perlod, that sald water supply
means consist oi~ axially directed openln~s or nozzles lnside
sald drum provided ln a cross æhaped pattern with the point
of inters~ction at the ce~ter of said drum.
The apparatus according to ~he ~nvention carrle~ out a
3(, combined washlng and rlnslng operation during the entire
operation wlth removal of mussel~ and other growth from the
net bag and out of said drum through ~aid contlnuously open
o~tlet openings~ Surprlsing].y, very strong and rapld removal
o~ growth from ~he net bag i~ ~chieved by contlnuous ~upply
Or water w~lch ls sprayed or 6purted onto the net bag ln6i~e
~ld druln, and by contlnuouc removal of water from ~aid drum,
prevel~tlng an~i volume of water to build up ln~ide the drum.

1 ~561 d
Tile reason for ~uch rapld and efficient cle~ning 1E probably
that the wet and heavy net bag 1 B very vlgorously worked
lnside said drum by t~e aid o~ the in~ard proJecting rldges.
Sald ridge~ have a considerable helght or radlal proJectlon,
in a preferred embodlment of the invention at least 10~ of
the lnternal diameter of said ~rum and will, t~u6, be ~ble to
llft the net bag to a high level ln~lde the drum, and they
will hat~e a strong impact on the net bag when lt falls do~n
ln the drum. There being very llttle w~ter ln said drum the
1~ effect of the lmpact of sald rldge~ on the net wlll not be
~ubdued. Such lmpact on the wet net b~g ~111 cause muæsel~
and other growth to be knocked off the me~h thread~, and the
released material will be continuou~ly wa~hed through the
outlet openings to be removed from the drum. Tests ~howed
1~ that a net bag with a diameter of approximately 40 m and a
depth of approximatel~ ~ m, i.e. a net bag of approximately
100 m2, is cleaned in the appar~tus ~ccording to the
lnvention 12~ le~s than half an hour.
The invention i~ disclosed in more deta~l below with refer-
ence to the drawings showin~ an embodlment of the apparatu~
according to the lnventlon.
Figure 1 shows the drum-sh~ped appar~tus ~o~ cleanlng net
bags for breedlng enclosures ln a side elevation.
Figure 2 shows an end view of sald apparatus.
Flgure 3 is ~ section~l view along llne A-A ln Flgure 2, ~nd
~igure 4 i~ a sectional view along llne B-B in Figure 1~
The apparatus acc~rding to the invention ec6entially comp-
rices a thin shee~ drum 1 which i~ provided to be rot~ed on
3~ a ~upport 2 Qnd ha~ ~n ln~ert opening 3. In~ide ~aid drum
four ~turd~T rldges 4 are provided evenly ~p~c~d on the drum
perlphery, ~;~id rldgeg hQve ~ height or radlal proJectlon
~ ~1

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_ that 1s at least 10~ of the internal diameter of ~ald drum.
In the shown embodlment the drum diameter ls ~pproxim~tely
2,4 m and the length ls ~pproxlmately 1,2 m. The height of
sald rldges ls 40 cm.
Four water cbannels 6, 7, 8, and 9 are provlded in~ide said
drum in one o~ the end walls of the drum. Sald channels
extend radlally from the centre of the drum, thus, fortnlng a
cross-shaped pattern. Water i3 supplled to æald channels
from a plpe 10 through the hollow drum ~ha~t 11 via a swivel
12. Channels ~, 7, 8, and 9 have a n~ber of openings or
nozzles 13 for water. In the shell 14 of the drum a num~er
of outlet slots 15 for water are provided. Drum 1 is rotated
by t~le aid of a diagrammatlcally indlcated motor 16. In
Flgure 3 the apparatus is shown in operation to clean a net
bag 16 which is lifted in the direction of arrow 17 by ridges
4, all the w~y to the top of ~rum 1, before it falls down
again onto the bottom of the drum. This operation ls carried
out contlnuously, w~ter being conti~uou61y supplied. Mussleæ
and other growths wlll be continuously carried awa~ with
effluent, especiall~ through outlet ~lot 15', when sald slot
ls faclng downwar~s t as shown in Flgure ~.

Representative Drawing