Note: Descriptions are shown in the official language in which they were submitted.
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~ his invention relates to the disposal of liquid
sludge by spraying it on the landO ~he invention particularly
relates to apparatus for use in a sludge dispersal
process of this t~pe
~ iquid sludge has been disposed of on the lana
for many years. In ~ne conventional method, sludge is
carried to the site in lorry-mounted or trac-tor-powered
sludge tanXers, from ~lhich it is pumped to the disposal
areaO ~he even distribution of sludge, especially during
wet weather, presents a problem with this system ho~ ver,
since the heavy equipment cannot be easily moved over the
ground. Pumps and portable pipe lines for spreading the
sludge has been proposed, but these systems are genera~ly
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labour intensive and are difficult to move from one site
to another.
uid sludge is gaining increasing acceptance as
a source of agricultural fertiliser and thus the disposal
of the sludge onto agricultural land is particularly
desirable, not only as a means of improving the land, but
~0 also as a means of dlsposing the unwanted sludgeO
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There is thus a real need for a simple portable sludge ¦ I
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disposal system which can be used under wet conditions and
hich does not in~olve the transport of hea~y equipment
over the ground.
We have now developed a simple
apparatus for spreadlng liquid slud_e over wide areas
in a unifor~ manner without the need to bring he~vy ta~kers
on~o the ground, which meets this needa
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According to the present inventlon we provide apparatus
for li~uid sludge disposal, comprising
0 a land sled~e having mounteG thereon a sludge spray
~, gun;
a mobile winching hose reel having a power cou~ling
for connection to a tractor po.~er ta'~e-off, and arranged
for connection to a pump suppl-~ of liquid sludge;
a flexible drag hose connec~ing the sledge and
gun to the winching ~ose reel;
; ~ a compressor coupled to anair~reservoir and arranged
to fill the reservoir ~rith compressed air automatically l.~hen
;~ the appara-tus is i~ use; and
'O ~ a release mechanism arranged to be actuated by
cessation of sludge flow in the hose, to release the compressed
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-air ~rom the reservolr through the ~ose and gun, thus emptying ~ :
substantially all~of the sludge therein.
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; The sludge spray gun is conveniently a sectoring
gun~ that is to sa~- one ~^rhich rotates in a reciprocal
fashion to spray the sludge in a wide sector, for example
a sector of abo~t 200C~ It is mounted on 2 sled~e, rather
than any kind of wheeled carrier, so that it can be
used over any terrain, whether rough or smooth~ ~he
apparatus is thus ideally suited to use on rough pasture
or on ploughed land.
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~he hose reel should be large enough to accommodate
the length of hose required, and for most agricultural
uses should preferably accommodate up to 700 feet (213 metres)
of hose. The hose reel is conveniently mounted with its
I axis horizo~tal and perpendicular to the line of travel
; of the sledge. ~he hose itself should be sufficiently
robust to enable the sledge and gun to be dragged in
under the winching action and is conveniently construc~ed
of a heavy duty thermoplastics material such as PVC or
a polyalkylene.
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; ~he air reservoir should be of a sufficiént size
2p and strength to contain the air required to blow the ;
sludge out of the entire hose When usinG a hose of ?oo feet
(213m) long and about 4 in(100mm~ diameter having~a~volume of ;
about 60 ft3 (1~7m3), the air reservoir~is~conven1ently
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about 20 ~t3 (0.565m3) in volume and able to stand a pressure
of up to 70 psi (5kg,'cm2). We have found that at this pressure,
a volume of 20 cubic feet is efficient in blowing out
residua.l sludge in a hose of this size. In other words,
it is convenient if the air reservoir volume is approximately
one third of the volume of the hose.
The relea.se mecha.nism which is activated by the
cessation o~ sludge flow in the hose, i5 conveniently a.
va.lvs which is opera.ted b~ a. drop in pressure in the sludge
supply. By suitable hydra.ulic a.ction, the pressure of' the
pumped sludge ~an be used to a.ctuate the compressor so tha.t
the air reservoir is filled an held full under pressure
while the sludge pressure is a.bo~e a. predetermined level.
A drop in the sludge pressure below this critica.l level
can then be u~ed to a.ctuate the release va.lve~ thus connecting
the a.ir supply in the reservoir to the hose.
In a preferred embodiment of the a.ppa.ra.tus according
to the present invention, the winching mecha.nism is pro~ided
with a.n a.utoma.tic stop mecha.nism a.ctuated by the return of the
sledge. In,a pa.rticula,rly a.dvanta.geous a.rra.~ement, the
ho~e reel mount is provided with a. pres~ure ba.r extending .,
perpendicula.rly to the line of tra.vel o~ the sledge and
connected to a. sla.ve hydra.ulic cylinder arra.nged to opera.te .
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the winching mechanism. At the start of the spraying
operation the hose is extended and the sledge is at a
point distant from the hose reel. While the sludge is -
being pumped to the spray gun, the sledge in being
winched towards the hose reel and the hose is wound
in. As the sledge reaches the hose reel, the pressure
bar is depressed and the automatic stop mechanism is
actuated. The stop mechanism can be arranged to control
not~ythe winching operation, but also the pumping
of the sludge. In this case as soon as the pumping of the
sludge is interrupted, the air in the air reservoir is
released and the sludge remaining in the hose is forcibly
ejected through the gun.
It will be seen that the apparatus according to the
present invention is of relatively light weight, as
compared with sludge tankers, and can be easily transported
by a small agricultural tractor of, say, 35 to 40 hp.
Conveniently, the sledge is arranged to couple onto the
hose reel and ~inching mechanism, so that both can be k~wed
by the tractor to the desired site, Sludge is supplied
to the apparatus by a portable pipe work which can be
laid along one side of the field to be sprayed for connection
; to a road tanker at the field gate. The portable pipe work
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can be conventional aluminium or thermoplastics pipe-
work conventionally used in field irrigation.
Thus, to spray sludge over a fie:Ld of up to 700 feet (213m~
long, a portable main pipe is laid along one end of the
field, conveniently with hydrants or take-o~f points
at appropriate inter~als along its length. A tractor
then tows the apparatus to the far end of the field
and drops the sledge which is anchored in position.
The tractor then returns to the ot~h end of the ~ield
laying the hose as it moves. The main pipe line is
then connected to the apparatus. A supply of liquid sludge
can then be pumped from a tanker on a near by
road or track, along the main pipe work to the hose
reel.
When the pumping of the sludge commences, the
anchor on the sledge is released and the sledge is slowly
winched towards the hose reel at a speed determined by the
volume of sludge to be applied to the strip land being
treated. When the sledge reaches the hose reel, the
pressure bar is depressed and the drive mechanism is
stopped. The pumping o~ the sludge is also disco~n~e~,
whereupon the air in the air reservoir is released through
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the hose and gun thus emptying the sludge remaining in the
system.
In order to spray the next section of the field,
it is then simply necessary for the tractor to pull the
coupled sledge and hose reel to the far end of the next
strip of field~and repea-t the process.
It will be seen that the entire process can be
operated by one man drivlng the tractor~ together with the
tanker driver. In fact it is possible for one man to do
both jobs. Littlei~ma~ua~ labour is involved as the movement
of the equipment and the repositioning for ea.ch
traverse of' the field is accomplsihed with the aid of' the
tractor~
The application of the sludge is completely controllable
and the amo~nt supplied to the field can be controlled by the
rate at which the sludge is pumped to the apparàtus and the
rate at which the sledge is winched,
If the contents of several tankers is to be sprayed,
it is convenient to use a sui.table diesel engine driven pump
at the roadside connection point, to which the tankers can
be connected in turn,
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In another preferred embodiment of the apparatus
according to the present invention, the sledge anchor is
arranged to be actuated b~ the sludge flow itself In this
embodiment, the anchor convenientl~ takes the ~orm of
an arm pivoted on the top of the sledge so that in
an upright position, the bottom end of the arm presses
into the ground. ~he arm is preferably spring-loaded
so that it is urged towards the ho i~o~tal position
; but held i~ a vertical position by a catch arra~ged to be
) released b~ the sludOe flow.
In this embodiment, there is no need for an independe~t
remote control mechanism to release the a~chor: the anchor
ig automatically released as soon as the sludge is pumped -to
the gun.
; I3he i~vention will now be further described with
reference to the acco~panying drawings in which: !:
Figure 1 is a side elevation of liquid sludge
disposal apparatus according to the present invention with
the hose extended;
3 Figure 2 is a perspective view of the apparatus showing~
the hose Iully reeled ln; and ~ -
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Figure 3 is a plan diagram of the field lay out
: and spraying pattern.
Referring to Figures 1 and 2 of the accompanying
drawings, it will be seen that the apparakus comprises
a land sledge 1 having mounted thereon a sludge gun 2
of the type which automatically sectors through a predetermined
arc. The sledge 1 is fitted with an anchor post 3 which
is pivoted on a top bar. The sledge 1 and gun 2 are connected
by a drag hose 4 to a winching hose reel 5 mounted on a
two-wheeled trailer 6. The hose reel is arranged for
power drive from a tractor PT0 via a chain drive 7.
A liquid sludge supply pipe and valve ~ connects
to the axis of the hose reel to supply sludge to the
inner end of the hose.
Also mounted on the trailer 6 is a compressor
i 9 and an air reservoir 10. The air reservoir 10 interconnects
via pressure-controlled valves 11 wi-th the sludge supply pipe
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Also mounted on the trailer 6 is a préssure bar 12
arranged to actuate a hydraulic cylinder 13 connected to the
drive control on the winching mechanism.
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On the sledge, the anchor post 3 is interconnected
with a flow sensing de~ice 14 arranged to release the
anchor post 3 when sludge flow to the gun 2.
Referring now to Figure 3 as well, a portable
alurninium main or flexible drag hose 15 is laid from the
field gate along one end of the field. At suitable inter~als
along the main or hose 15 are supplied hydrants 16.
In order to spray a first strip of the field,
the sludge disposal apparatus is towed by a tractor to
the starting position 17 and the sledge 1 is disconnected
an~th~ anchor post 3 actuated to hold the sledge 1 in place.
The tractor then tows the trailer 6 to the terminal hydrant
on the main 15, laying the hose 4. Sludge is brought to the
field gate in a tanker 1~ and is supplied to the main 15
by a flexible hose 19. The sludge is pumped to the
apparatus by the tanker, or by an independent diesel
powered power at the field gate.
When pumping commences, the liquid flows actuates
the control 14 and releases the anchor post 3~ The winching
mechanism is then started and -the air compressor 9 automatically
charges up the air reservoir 10, to 60 or 70 psi (4 or 5kg/cm2)
pressure.
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The sledge 1 is slowly drawn towards the trailer 6
as the hose 4 is reeled, thus spraying sludge over a
generally rectangular strip of the field~ A tanker
fitted with a pump unit capable of discharging 40 to 60 m3/H
(~00-13200 gallons per hour) with a pressure range of
4.2 to 7.0 kg/cm2 (60 to 100 psi3 can enable the sludge
to be spread over a strip 46 m (150 feet) in wldth.
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When the hose 4 is fully reeled in, ~he sledge
1 is pulled against the pressure bar 12, thus actuating
the hydraulic cylinder 13. The winching drive is then
cut off and valve 11 empties air reservoir 10 through the
hose 4 and gun 2, thus discharging the remaining sludge
therein.
To spray the next strip of the field9
the tractor then tows the trailer 6 and sledge 1 to the
next position 20 and the process is repeated.
It will be seen that the only equipment which enters
the field is the tractor and the sludge disposal apparatus
according to the invention. The heavy tanker remains
~n khe road, and the entire operation in the field is
operated by one man~
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