The
methods to operate with PNEUMA pump are the following:
The
HOLE DREDGING SYSTEM for loose bottom materials (sand-soft silt) and for deep
depth.
OPERATING METHODOLOGY
The pump body is suspended by shears and lifted by a
winch. To
start dredging operation the pump is lowered until the three inlet pipes are
in contact with the bottom.
By keeping the steel wire of the lifting winch slightly slack, the inlet pipes will be continuously immersed into the material to be dredged.
Due to the hydrostatic head, as soon as the distributor releases the pressure from each one of the cylinders in sequence, there will be an immediate "in-rush" of the material through the inlet pipes.
The greater the depth, the more intense will be the suction.
No induced turbidity is produced when dredging loose materials which enter
into the inlet pipes without the use of rotating cutters.
The here below picture clearly shows the hole just created during the first dredging phase.
The TRAILING SYSTEM for compacted bottom materials (clay -compacted silt) cohesive and polluted sediments in general.
OPERATING METHODOLOGY
To
obtain the maximum solid content, the problem consists in facilitating the
collection of the material by the pump. This is done by trailing the Pump
and forcing 
the material
to penetrate through the shovels into the cylinders as it is dredged forward.
To dredge by the trailing system, the Pneuma Plant, equipped with relative
shovels, is assembled on a pontoon fitted with four main winches, two to trail
it and the others to return it.
The winches will trail the pontoon at a speed which may vary from 1 to 5 m/min
depending on the compactness of the material to be dredged.
The return winch speed will be greater and is normally about 20-30 m/min.
The shovels and the pump are connected to a lifting winch placed on the stern
and to a positioning winch placed on the bow of the pontoon.
With this system the movement of the barge is directly transferred to the
shovels which will be forced into the material to be dredged.
Using the trailing system, it is possible to reach a very high solid content
in the mixture, i. e. 80-90 per cent. This is due to the fact that the shovels
are equipped with fixed blades which cut the material into strips allowing
it to be pushed inside the pump body by the hydrostatic head.
Because of the particular shape of the shovels, those are continually buried
in the material to be dredged so that there is little possibility of water
entering the pump body and mixing with the solid material. Similar efficiency
can also be obtained when dredging polluted materials. Furthermore,
the Pneuma system provides a distinct advantage over traditional dredges in
that it does not create secondary pollution by disturbing the material on
the bottom, as the fixed blades cut the material at a low advancement speed.
Trailing in shallow waters
In
shallow waters, up to 4/5 mt. depth, it is possible to apply the pump body,
completed of vacuum system, assembled in line, guided by a frontal sliding
device and suspended by shears.
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NO INDUCED TURBIDITY DURING OPERATION IN COMPACTED BOTTOM MATERIAL (SILT-MUD-CLAY)
The
PNEUMA SYSTEM does not create secondary pollution by disturbing the material
on the bottom, as the fixed blades cut the strata of material, allowing the
shovels to penetrate in it at a very low advancement speed and without any
kind of rotating cutters.
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• • •
Fishing
close to a Pneuma dredge in operation is the best demonstration of the absence
of induced turbidity
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