Note: Descriptions are shown in the official language in which they were submitted.
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"SUCTION HARVESTER FOR A~UATIC PLANTS AND ANIMALS"
T HNICAL FIELD
This invention relate6 to a 6uction harvezter for
aquatic plants and animal~ and ha6 been devi~ed
particularly ~hough not solely for the control of nui~ance
aquatic plant or animal zpecie~.
BACKGROUND ART
In the past various types of aquatic harve6ters or
weed cutter~ have been provided, operating on a princi~le
whereby aquatic plants are mechanically cu~ at the end o~
a moving conveyor belt which then carries the plants on
board the harvester. Such harvesters have the
disadvantage that ~he harvesting i~ not selective in that
all material above the height of the cutting blades iz
~5 removed. Such machinery is also of considerable weight,
requiring a comparatively deep draught ves~el in order to
accommodate the machinery in a ve~sel of manoeuvrable
proportion~. This is a dizadvantage with an aquatic
harve~er which iB frequently reguired to operate in
sh~llow water aa aqu~tic plant~ ar~ mozt prevelant in
shallow water due to light penetration.
Some known aquatic harvQ~terz are ~upported by wheel~
or trac~ which run on the sea bed (or lake bedO etc.) to
support the harvester, rather than being supported by a
float veszel. Such land bas~d machinery has the
di~advantage tha~ i~ can often GaUse ecological damage to
the zea bed due to the di~turbance caused by the wheelz or
tracks.
It ifi a further feature of known type~ of floa~ing
harve~ters that they are norm~lly powered by devices ~uch
a~ paddle wheels which are inefficient in their u~e of
energy, and more importantly, provide no refarence to the
bottom Or the water body. Drif~ due to wind and current6
ma~e~ pre~ize harvefiting of an area difficul~. if no~
impo~sibl~, ~hQeled or track~d harve6ti~g machinery
provide~ good ground r~ferenca but cau6ez con~iderable
di~turbance to ~he subztra~e and da~ag~ ~o t~e ecology of
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the aquatic environment.
It is therefore an object of the present invention to
provide a ~uction harve~ter for aquatic plants and
harve6ter6 which will obviate or minimise the foregoing
disadvantage~ in a ~imple yet effective manner, or which
will at least provide the public with a useful choice.
DISC~OSU~E OF INVENTION
~ ccordingly, in one a~peot the invention consis~s in
a method o~ harvesting aquatic plants and animals
comprising the steps of:
(1~ providing a vessel incorporating a manoeuvrable
nozzle protruding therefrom connected to a pump arranged
to ~uck water through the nozzle;
(2) manoeuvring the ve~sel and~or ~he nozzle to
locate the nozzle in a po~ition adjacent aquatic plant6 or
animals desired to be harvested;
(3) operating the pump to ~uck water and entrained
aquatic plants or animal~ ~hrough the nozzle; and
(4) di~charying the water and entrained aquatic
plant~ or animals from ~he pump to a desired di~charge
location.
Preferably the pump compri~es a variable rate pump
and the method includes selecting the ~low rate of water
through the pump to control the degree Oe ~uction applied
to the nozzle.
P~eferably the nozzle i6 manoeuvred through a
controlled ~weep pa~tern relati~e to the ves~el during
operation of the pum~.
Preferably the ve6~1 i8 manoeuvred in shallow water
by controlled rotatlon of a plural~ty of wheels with
radially extending spike~, the wheelfi having substantially
horizontal axe~ and being mounted to the ve~sel ~uch ~at
the wheels may be rai6ed or lowered to engage the ends of
the lowermost 6pikes with the bed of the body of w~ter in
which the vessel is floating.
In a further as~ct ~he invent~on con~st~ in a
harvester ~or aqu~tic plant~ and animal~ compri~ing a
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suport vessel. a manoeuvrable nozzle protruding from the
ve~sel, and a pump arranged to ~uck water and entrained
aquatic plants or animal~ through the nozzle and discharge
them to a de~ired discharge location.
Preferably the nozzle ~orms the outer end of a nozzle
ar~ extending radially outwardly from a substantially
vertical pivot mounted on the vessel, and wherein
actuation means are provided arranged to rotationally
oscillate the nozzle arm about the pivot causing the
no7,zle to sweep back and forth through a predetermined arc.
Preferably the height o~ the nozzle arm is adjustable
relative to the vessel.
Preferably the pump has a variable flow rate
controlled by an operator of the harvester.
Preferably the pump is provided with an auxiliary
priming pump arranged to ~upply water under pressure into
the suction chamber of the main pump, the priming pump
being operable on demand by an operator to back flu6h the
nozzle and clear any blockage therein,
Preferably the vessel i~ provided with a plurality of
wheels controllably rotatable by drive means about
~ub~tan~ially horizontal axes, each wheel having a
plurality of radially extending spikes and being mounted
to the vessel such that the wheel~ may be raised~or
lowered to engage the end6 of the lowermost spikes with
the bed of the body of water in wbich the vessel i~
floating,
Preferably each whsel is mounted on the end of an arm
attached to the ves~el by way of a ~ubstantially
horizontal pivo~ each ~heel being able to be rai6ed or
lowered by pivoting the arm r21ative to the ~essel.
BRI~F DESCRIPTION OF DRAWINGS
Notwithstdnding any othsr ~orms that may fall within
it~ ~cope~ one pre~erred form of the invention will ~ow be
de~cribed. by way of exa~ple only, wi~h referenc~ to ~he
accompanying drawing~, in which:~
Fig. 1 is ~ diagra~matic ~ide view of a ~uction
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~arvester according to the invention:
Fig. 2 i~ a diagrammatic plan view of the harvester
~hown in Fig. l;
Fig. 3 is a diagrammatic frontal view of the
harvester shown in Fig. l;
Fig. 4 i~ a side view to an enlarged scale of the
nozzle actuation and control mechanism of the harve6ter
~hown in Fig. l; and
Fig. ~ is a plan view of the nozzle o~cillation
actuation mechanism shown in Fig. 4.
MOD~S POR CARRYING OUT TH~ INVENTI~N
In the preerred ~orm of the invention a suction
harvester for aqua~ic plant~ and/or animals i~ con~tructed
a~ follows.
~5 The harvester co1npri~e~ a ves~el of any conveniant
configuration bu~ pre~erably in the form of a barge formed
~rom t~o ~ealed pontoons ~1) located either side of and
secured to a central open-top barge t2) which is
preferably of shorter length than the pontoons (1),
leaving a~ area o~ open wat~r between the pontoons at ~he
f~ont of the ves~el. The central barge (2) is used ~o
~upport and locate an engine (3) (preferably a di~sel
engine) coupled to hydraulic pumps (4) and (5). Also
within the central barge (2) there is loca~ed a '
cerltrifugal pump (6) driven by way of a coupling (7) fro~
a hydraulic motor (8) connected to and driven by the
hydraulic pump (4) by way of hydraulic lines (9).
The hydraulic motor (8~ i~ pref~rably a v~riable
~peed hydraulic motor con~rolled by ~uitable hydraulic
valvinq (not ~hown) under the control of an op~rator from
hi~ po~ition in a control cabi~ ~10). The control cabin
i6 preferably located at the front end o~ the vessQl ~o
that the operator has a good view of the ~uction nozzle
(as described below~.
The centri~ugal pump (6) i~ pre~erably a high volumQ
c~ntri~ugal pu~p capable of han~ling ~olid m~t~rials and
ifi ~ypi~ally o~ the inducsd vortex type. Whe~ operati~g
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with certain aquatic material~ it may b~ necessary to
employ a ma~cerating impeller in the pump to cut entrained
material to a ~ize which will not bind th~ pump.
The inlet (ll) to the pump (6) i~ connected by way of
a flexible hose (12) to a hollow nozzle arm (13) which
terminates at it~ forward end in a nozzle (14) protruding
~orwardly ~rom ~he ves~el. The outlet (15j from the pump
(6) is also coupled to a flexible hose (~6) for discharge
o~ material $ro~ ~he pump to a de~ired di~charge location.
A gland pump (17) is provided, driven by the motor
~3), and arranged to pump water from an inlet immersed in
a ~trainer (not ~hown) at the rear of the vessel to ~he
bearing of the ~ain pump (6).
The main pump (6) is primed by an auxiliary
centrifugal priming pump (18~ driven by a hydraulic motor
(19) ~upplied with hydraulic ~luid under pres~ure ~rom the
hydraulic pump (5) which i~ driven by the motor (~) and
also u~ed to provide hydrualic fluid under pre~sure to
various hydraulic ram~ on the harve~ter a~ will be
described further below. The auxiliary priming pump (18)
draw~ water ~rom an i~let immer~ed beneath ~he ~e~sel and
~upplie~ that wa~er under pre~ure through a conduit (20)
by way o~ a non-return val~e (21) into the inlet chamber
of the main pump (6). In this way the auxiliary priming
pump may be u~ed to fill the inlet to the main pump (6)
with water to prime the main pump prior to operation.
Reservoi~6 o~ hydraulic Eluid and oP fuel for the
motor (3) may be conveniently located in tank6 t22) and
(23) located in the pontoons (1). The nozzle arm (13~ i~
located and manoeuvred by an a~paratu~ which w;ll now ~e
de~ribed with particular r~ference to FigE. 4 and 5.
The nozzle arm (13) i~ supported by a ver~ical 6ha~t
(29) which is typically welded to the nozzle arm at point
(25). A6 an optional faature the nozzle arm which i~
~hown horizon~ally mounted in the attached drawi~gg, ~ay
be ~ecured ~o ~he vertical ~ha~t ~24~ by way of a
horizontal ~i~ot, enabling the nozzle arm to be tiltQd
~ 9~s
downwardly ~o a predetermined inclination.
The vertical ~haft (24~ i~ located within a tube (25)
and axially ~upported within the tube by way of a collar
(26) 50 that the shaft protrude~ from the top and bottom
of the tube (25). The tube (25) is in turn located by a
platform (27) and ~upport bracing (28).
The platform ~27) i~ in turn located by rollers (28)
engaged with ver~ical columns (29) extending upwardly from
a platform (30) located on the pontoon~ (1). The height
of the platfor~ (27) may be adjusted relative to the
~upport platform (30) by moving the rollers (28) up and
down within channels in the column~ (29) under the control
of a double acting hydraulic ram (31) secured at its lower
end (32) to the platform (30) and havin~ it~ upper end
(33) connected to support struts (34) which in turn engage
with and support the platform (27) and the vertical tube
(25). In thi6 manner the en~ire platform (27), the tube
(25), ~haft (2~) and nozzl~ arm (13) may be moved
vert;cally by op~ration of the hydraulic ram (31) supplied
with hydraulic pre~sur~ from the pump (5) controlled by a
valve opsrated by an operator in the cabin ~10).
The nozzle arm (13) i~ caused to rotationally
o~cillate about the pivot formed by the ~er~ical ~haft
(24) by way of an actu~ting mechanism comprising'radial
arm~ (35) (Fig. S~ extending outwardly from the ~haft (2~)
and connected at their outer end~ to yoke6 (36) corlnected
in turn o~ the actuating rods (37) of hydraulic rams (38~,
anchored at their oppo~ite end6 to a 6upport bracket (39)
on the plat~orm (27~. The hydraulic rams (38) are
operated by hydraulic fluid 6upplied ~rom the pump ~5)
through a pre~ure opQr~tsd hydraulic pllot Va1V~D
activated au~omat~cally at the end of each ~weep of She
nozzl~ arm (13), reversing the ~low of hydraulic oil
through the rams (38) and consequently She dirsction of
06cillation of ~he nozzle arm ~13). The ~weep 6peed i~
controllabl~ by a valve in the operator'~ ca~;n ~10~ and
the length o~ the 6~ee~ i~ aajustable by altering the
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di~tance along the radial arm~ ~34) and (35~ at which the
yoke~ (36) are located.
In this manner the nozzle arm (13~ may be cau~ed to
oscillate about the pivot of the shaft (24) through a
predetermined arc at a speed controlled by the operator,
while the height of the nozzle ~rm and hence of the nozzle
(14) may al60 be cont~olled by the operator by way of
hydraulic ram t31).
The vessel may be propelled in deep water by any
~uitable propulsion means such as an outboard motor or a
drive leg powered directed or indirectly by the motor (3),
or al~ernatively may be towed to a de~ired 6hallow water
location for o~eration. Once in the ~hallow water
location the vessel is po~itioned and manoeuvred by way of
wheels (90) having horizontal axe~ and mounted on the snds
of arm~ (41) pivo~ally mounted to the ~ide~ of the
pontoons (1) by way of horizontal pivot pin~ (g2) and
rotatable thereabout by hydraulic rams ~43) operable
be~ween trunions (44) on the arms (~1) and support lug~
(45) attached to the pontoon. Opera~ion of th~ hydraulic
rams (43) cause~ the arm~ (41~ to rotate and hence rai6e
or lower the wheel~ (40) relative to the ve~sel, In the
preferred for~. o~ the invention two ~uch se~ of wheels
and arm~ are provided located on eith0r side of ~he ve~6el
and protruding ~orwa~dly therefrom a6 ~hown in Pig~, 1 and
.
Each wheel (40) i~ provided with radially extending
6pikes (46) which can engage with the 6ea bed ~or th~ bed
of any other water body in ~hich the water i~ floating)
upon lo~ering of the arm to a de~ired depth. Each wheel
i6 provided with a hydraul~c drive motor (47~ able to
rotate the whe~l when powered by hydraulic fluid fiupplied
under pres6ure from the pum~ 55) by way of ~ontrol valve~
in the operator'~ cabin ~10), By operating tho~e control
valva~ the operator can indep~ndently rotate each of ~he
drive ~o~or~ (47) at a d~ir~d ~peed and hence cause each
~piked wheel to ~ove forwardly or backw~rdly propelling or
manoeuvring the ve~sel to a de~ired location. The two
drive moto~6 (47) May of course be operated independently,
e.g. one forward and one in rever~e, ~o cau~e the ve~sel
to turn in a de~ired manner.
~here required for further location of the vessel a
further pair o~ arm6 (48) may also be provided at the rear
of the ves~el pivotally mounted to ~he pontoons by way of
pivot~ (4~A) controlled by hydraulic ram6 (50) in a
similar manner to the arms (41), pivot~ (42) and hydraulic
rams (43), re~pectively. The arms (48) are al~o provided
with ~p;ked wheel~ (49) which are free to free-wbeel on
the ends of the arms (48~ and are not provided with
hydraulic drive motor~.
In u~e the harvester i~ po~i~ioned in a location
where it i~ de~ired to harve~t aquatic plan~ or animals
whereupon the vessel may be manoeuvred into a de~ired
location and held in that location by engaging the 6piked
wheel~ (4V) and (49) with the ~ea bed and manipulating the
hydraulic motor~ (47) accordingly. The pump (6) may then
be driven at a desired speed by ~he hydraulic motor (8)
causing water to be ~ucked into the pump ~rom the nozzle
(14) and di~charged through the outlet ho~e (16). The
nozzle (14) is vertically po~itioned by the operator by
way of the hydraulic ram (31) ~o as ~o 1ocate th~ nozzle
at the de~ired depth and the nozzle i~ then o~cillated
over a predetermined swee~ path by operation o~ the
hydraulic rams (38). The oeerator in ~he cabin ~lO) may
control the ~weep rate of the nozzle, and the deyree of
suction applied by the pump (6) ~o a~ to achieve the
de~ired harvesting e~fect which may vary depending on the
loca~ion an~ th~ plant or anim~l which it is desired ~o
harvest. The dire~t 6uctivn principle allow~ the force
applied to the m~teri~l ~o be harv~ted to be altered by
adju~ting pu~p ~peed and the operat;ng depth of the nozzle
in the wat~r column. In thi~ way a r~ng~ of harva6ting
~unction~ i~ made pos~ible. ~or ~xample, management plans
m~y require t~e total cleari~g of an are~ ~or recreational
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purpo~e6, or the removal o~ floating algal mat6 ~
~i~ually enhance an area, or the removal of entangled algi
and dead plant material fro~ a ~eagrass bed to improve
light penetration. The ab;lity of thi~ harve~ter to
re~ove material ~electively ha~ important implication~,
particularly in ecologically sen~itive area6,
Becau~e the machinery u~ed in ehe harvester according
to the invention i~ comparatively light in weigh~, it i6
po~ible to mount the harve6ter in a shallow draught barge
formed from the pontoon~ (1) and (2) so as to be operable
in ~hallow water. As light penetra~ion is a major factor
in limitin~ the depth of water in which aquatic plant6
will grow, the ability of the harvester to opera~e in very
shallow waters is important. With the bouyancy provided
by the two pontoon~ and the smaller central barge (2),
the ~uction harve6ter of the type shown in the drawings
draw~ approxima~ely 175 mm fully laden and it~ moving
nozzle (14) i~ capable of harvesting in les~ than 300 mm
of water without entraining ~ignificant amount~ of air
from ~he fiurfacs. The operatin~ depth could be further
reduced by providing a ~heild over the nozzle (14~ ~o
inhibit vortex action. The 6hallow draught capability of
the harve~ter according to the invention ~ignificantly
increase~ ~he area of a shallow water bod~ over ~hich the
harve~ter can operate and ~o reduce~ the need ~or, and the
ecological damage cau6ed by, land based machinery u~ed in
an aquatic environment.
It iz a further feature of the harvester accerding ~o
the invention that the water and aquatic material i~
pa6~ed through the main pump (6) and discharged ~hrough
the flexible ho~e ~16~ which can deliver to any desir~d
location. Such locationE could typically be:
(a) to a ~e6h separator basket ~ituated on the
harva~ter;
tb) tc a me~h 6eparator ba5ket on a transporter
pontoon:
(c) dire~tly o~r ~he ~ide of the vessel should
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di~ruption of al~al beds be the prime objecti~e; or
(d) to a buoyed delivery hose to pump material~ to
the shore.
It i~ a further ~eature of the harvester according to
the invention that the propulsion and ~anoeuvring sy~tem
provided by the spiked wheel~ t40~ and (99) provides good
ground re~erence and so make~ accurate harve~ting
po~sible. Little energy is required to propel the vessel
by this method and disturbance to the substrate and
ecology i~ kept to a minimum. It is also po~ible to
control the location of the vezsel accura~ely against
drift due to wind and currents.
It is a further feature of the invention tha~ the
auxiliary priming pump (18) may be u~ed during operation
to clear any blockage that may occur in the nozzle (14).
Should ~uch a blockæge occur the operator can si~ply stop
the pump (6) by operating the control ~alve ~o the
hydraulic motor (8~, and then activate the priming pump
(18) by way of hydraulic motor (l9) cau~ing exce~ priming
water to back flow ~hrough the nozzle (14) and force any
blockage from the nozzle end.
