Improvements in Suction Dredgers.
Year: 1897

page_text: Date of Application, 1st July, 1897
CL
ليم
1007
Oth lan
1000
PROVISIONAL SPECIFICATION.
Improvements in Suction Dredgers.
I, LOUIS COISEAU, of 120 Avenue des Champs Elysees, Paris, in the Republic of
France, Engineer, do hereby declare the nature of this invention to be
follows:
as
Suction dredgers as heretofore used for dredging purposes are operated by
causing the end of the suction pipe to penetrate the sand or like substance to be
dredged, thus forming conical holes which will be gradually levelled by the
agitated water; or by disaggregating the soil by the aid of blades while
simultaneously causing it to be sucked up.
All these dredging machines must be connected to chains which are operated
so as to move the dredgers in the desired directions; they consequently obstruct
the water courses in which they are used and impede the navigation, which in
much frequented harbours and canals, constitutes a serious objection and adds
to the cost.
Suction dredgers are not well suited for dredging mud, muddy sand or sand of
fine and light character.
The dredging machine forming the subject of this invention overcomes all
these inconveniences.
The dredging is effected while the dredger is in motion, and the dredging takes
place in regular layers, of a depth which can be adjusted at will.
Mud, miry or like sand and like spoil is drawn in practically without water,
owing to it continually entering the exhauster as the dredger advances, without
affording the water sufficient time to enter. Heavy sand is drawn in as in the
case of ordinary suction dredgers but is removed from the bottom of the water-
way in regular layers without forming holes.
The dredger constructed in accordance with this invention consists of a vessel
capable of being moved by any suitable means such as screw propellers paddle
wheels or towing by means of windlasses fitted on its deck or on land.
The vessel is divided into three main parts. At the forward part, the equipment
chamber is arranged; in the centre part the receiving tank or hopper is arranged
with the depository pits at each side. At the rear part, the steam boilers, pumps,
steam engines, and screw propeller or propellers are provided.
The suction pipe may be arranged in the centre part, or it may be divided into
two starting from each side of the vessel and uniting at the extremity where the
suction takes place.
A chief novelty of the apparatus consists in the suction pipe, and its method of
operation and consequently in the action of the dredger itself.
The suction pipe can act either by compression or by traction, and will be
constructed accordingly.
If the suction or exhaust pipe act by compression the mouth of the pipe may be
rectangular, its width and its height being proportional to the cube to be dredged
per unit of time; and it is divided by walls or partitions at suitable intervals apart

page_text: to prevent any obstructive matter entering the pipe. Above the mouth the pipe
is slightly curved and then passes in a straight line up to its point of connection
to the dredger and it forms a very rigid beam, capable of taking up the stresses
or vibrations from the engine.
The pipe may be round or oval and may be either joined to, or formed in one
part with the rectangular mouth.
Under the lower part of the suction pipe is arranged a roller or drum slightly
less in length than the width of the pipe, and the shaft of this roller is connected
at each extremity to a pair of rods or links one of which is pivotted to a fixed pin
or stud on the pipe the other being pivotted to a pin or stud connected to a screw
nut, which may be raised or lowered by rotating the screw on which it runs this
operation being effected from the deck by a hand wheel or the like secured on a
shaft carrying at its lower end a bevel wheel which drives a horizontal shaft, on
the extremities of which, bevel pinions are keyed, which, through the medium of
gear wheels actuate the screws and consequently impart motions to the nuts.
According as the roller is lowered or raised by the action of the screws the
thickness of the layer to he dredged is either increased or diminished. For very
soft and liquid mud it is preferable to completely immerse the mouth of the
suction pipe therein in order to draw in as little water as possible. For sand and
gravel, on the other hand, it is necessary to leave a small free space in order to
draw in a mixture thereof with water such that it will not obstruct the pump.
The roller thus controls the thickness of the layer to be dredged in a perfectly
reliable manner and permits of the bottom being levelled with great accuracy.
A chain or cable is fastened at its lower end to the pipe and at its upper end to
lifting tackle connected to a windlass to raise or lower the suction pipe as the
windlass is operated.
The operation of the dredger is as follows:--
The travel of the dredger is so regulated that only such a quantity of spoil is
forced into the suction pipe as can be raised by the pump. The end of the suction
pipe is lowered. Through the action of the propeller the matter to be dredged
then enters the mouth; the thickness of the layer to be dredged is then regulated
by the aid of the aforesaid roller and the pump raises the spoil which enters the
pipe the operation somewhat resembling planing parallel strips of spoil being
removed one by one in lieu of holes being formed or of applying an oscillating
action with a disaggregating tool as in suction dredgers hitherto used thus the
use of mooring chains is avoided and there is consequently no loss of time incurred
in fastening and disconnecting them and moreover navigation is not in any way
impeded.
The
When the suction pipe is to be worked by traction, the mouth instead of being
curved in an upward direction as previously described is curved toward the bottoni,
and the roller or drum in lieu of being placed beneath the suction pipe is
arranged at the back of the mouth thereof. The operation of this dredging
apparatus is similar to that previously described but instead of the pipe being in
compression it is in tension which is preferable for steering the boat.
rectangular mouth is connected to, or formed in one part with, the pipe. The
adjusting device is operated by a hand wheel the movement of which is trans-
mitted to two shafts fixed on the pipe through the medium of bevel wheels this
movement being transmitted by other bevel wheels to the screws carrying the
screw nuts which constitute the bearings for the shaft of the roller two brackets
fixed to the pipe serving to support the adjusting device.
As the dredger is moved along it may come into contact with a portion of
ground or other obstacle presenting such resistance as to cause the pipe to rise.
To avoid this a rigid rod may be fixed to the dredger, which rod bears against the
pipe through the medium of an anti-friction roller. This rod. carries a rack bar
which gears with a pinion rotated by a crank-handle. A roller serves as a guide
for the aforesaid rigid rod and a yoke or bracket ensures its vertical position. A

page_text: ratchet wheel with pawl mounted on the shaft of one of the pinions prevents the
rod from accidentally rising.
This apparatus may also serve for elevating the pipe, for this purpose all that
is necessary is to add to the bottom of the aforesaid yoke or bracket a second roller
which bears against the under side of the pipe.
To obtain a better distribution of the stress, two similar apparatus, placed
symmetrically, relatively to the axis of the boat, may be provided, with their
corresponding anti-friction rollers working on one and the same shaft.
The connection which permits of the suction pipe being lifted, may be of any
suitable construction, and the mechanical arrangements which allow of controlling
the movement of the connection or of the ascending and descending movements of
the drum or roller which rearwardly adjusts the working spout of the suction
pipe may be modified, and the suction pipe may vary in shape and section
according to the nature of the work.
I may place the drum which regulates the height of the inlet of the pipe from
the bottom before the said pipe if desired, or such adjustment may be obtained
by means of two drums, one in front and the other behind the suction pipe.
Dated this 1st day of July, 1897.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
I, LOUIS COISEAU, of 120 Avenue des Champs Elysees, Paris, in the Republic of
France, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:―
Suction dredgers as heretofore used for dredging purposes are operated by
causing the end of the suction pipe to penetrate the sand or like substance to be
dredged, thus forming conical holes which will be gradually levelled by the
agitated water; or by disaggregating the soil by the aid of blades while
simultaneously causing it to be sucked up.
All these dredging machines must be connected to chains which are operated
so as to move the dredgers in the desired directions; they consequently obstruct
the water courses in which they are used and impede the navigation, which in
much frequented harbours and canals, constitutes a serious objection and adds
to the cost.
Suction dredgers are not well suited for dredging mud, muddy sand or sand of
fine and light character.
The dredging machine forming the subject of this invention overcomes all
these inconveniences.
The dredging is effected while the dredger is in motion, and the dredging takes
place in regular layers, of a depth which can be adjusted at will.
Mud, miry or like sand and like spoil is drawn in practically without water,
owing to it continually entering the exhauster as the dredger advances, without
affording the water sufficient time to enter. Heavy sand is drawn in as in the
case of ordinary suction dredgers but is removed from the bottom of the water-
way in regular layers without forming holes.
In order that my invention may be clearly understood I will describe the same
with reference to the accompanying drawings, in which-
.

page_text: ⋅
Fig. 1 represents in longitudinal section a dredger to which the apparatus
forming the subject of my invention, is applied.
44
Fig. 2 represents in detail the lower end of the suction pipe of the dredger and
the adjusting device by which the thickness of the layer to be acted upon and
removed is varied.
This
Fig. 3 shews in front elevation the opening of the suction pipe.
Figure 4 represents a second form of my invention in which the suction pipe,
instead of working by compression, as in the case of Fig. 1 is in tension.
Figure moreover represents a device by which the rigidity of the pipe is ensured,
this device can be further made use of for elevating the said pipe.
Fig. 5 is a detail view of the adjusting device shewn in Fig. 4.
Like reference numerals indicate like or corresponding parts throughout the
various Figures of the drawings.
The dredger constructed in accordance with this Invention, consists of a vessel
capable of being moved by any suitable means such as screw propellers padillé
wheels or towing by means of windlasses fitted on its deck or on land, a screw
propeller being used in the arrangements shewn in the drawings...
The vessel is divided into three main parts. At the forward part marked 1 and
2, the equipment chamber is arranged; in the centre part the receiving tank or
hopper 3, with the depository pits at each side. At the rear part, marked 4 and 5
the steam boilers, pumps, steam engines, and screw propeller or propellers are
provided.
The suction pipe 6 may be arranged in the centre part as shewn, or it may be
divided into two starting from each side of the vessel and uniting at the extremity
where the suction takes place.
A chief novelty of the apparatus consists in the suction pipe, and its method of
operation and consequently in the action of the dredger itself.
The suction pipe 6 may work either by compression or by traction, and will be
constructed accordingly.
If the suction or exhaust pipe act by compression (Figs. 1 and 2) the mouth of
the pipe may be rectangular, its width and its height being proportional to the
cube to be dredged per unit of time; and it is divided by walls or partitions '7,
(Fig. 3) at suitable intervals apart to prevent any obstructive matter entering the
pipe. Above the mouth the pipe is slightly curved and then passes in a straight
line, up to its point of connection to the dredger and it forms a very rigid beam,
capable of taking up the stresses or vibrations from the engine.
one
The pipe may be round or oval and may be either joined to, or formed in or
part with the rectangular mouth.
Under the lower part of the suction pipe 6 is arranged a roller or drum 8 slightly
less in length than the width of the pipe; the shaft 9 of this roller is connected at
each extremity to a pair of rods or links 10 and 11 one of which, 11, is pivotted to
a fixed pin or stud 13 on the pipe the other, 10, being pivotted to a pin or stud 12
connected to a screw nut 14, which may be raised or lowered by rotating the
screw 15 on which it runs, this operation being effected from the deck by a hand
wheel 16 (Fig. 1) or the like secured on a shaft carrying at its lower end a bevel
wheel 17 which drives a horizontal shaft, on the extremities of which, bevel
pinions 18 are keyed, which, through the medium of gear wheels 19 and 20
actuate the screws 15 and consequently impart motions to the nuts 14.
According as the drum or roller is lowered or raised by the action of the
screw 15 the thickness of the layer to be dredged is either increased or diminished.
For very soft and liquid mud it is peferable to completely immerse the mouth of
the suction pipe therein in order to draw in as little water as possible. For sand
and gravel, on the other hand, it is necessary to leave a small free space in order
to draw in a mixture thereof with water such that it will not obstruct the pump.
The roller 8 thus controls the thickness of the layer to be dredged in a perfectly
reliable manner and permits of the bottom being levelled with great accuracy.
"A chain or cable 21 is fastened at its lower end to the pipe 22 and at its upper

page_text: end to lifting tackle 23 connected to a windlass 24 to raise or lower the suction
pipe as the windlass is operated.
The operation of the dredger is as follows:-The travel of the dredger is so
regulated that only such a quantity of spoil is forced into the suction pipe 6 as
can be raised by the pump. The end of the suction pipe is lowered and through
the action of the propeller the matter to be dredged then enters the mouth; the
thickness of the layer to be dredged is regulated by the aid of the aforesaid roller 8
and the pump raises the spoil which enters the pipe; the operation somewhat
resembling planing, parallel. strips of spoil being removed one by one in lieu of
holes being formed or of applying an oscillating action with a disaggregating tool
as in suction dredgers hitherto used; thus the use of mooring chains is avoided
and, there is consequently. no loss of time incurred in fastening and disconnecting
them and moreover navigation is not in any way impeded.
When the suction pipe is to be worked by traction as shewn in Figures 4 and 5,
the mouth instead of being curved in an upward direction as already described is
curved toward the bottom, and the roller or drum 8 in lieu of being placed beneath
the suction pipe 6 is, arranged at the back of the mouth thereof. The operation of
this dredging apparatus is similar to that already described but instead of the
pipe 6 being in compression it is in tension which is preferable for steering the
boat. The rectangular mouth is connected to or formed in one part with, the
pipe 6 (Figures 4 and 5). The adjusting device is operated by a hand wheel 16
(Figure 4) the movement of which is transmitted to two shafts fixed on the pipe 6
through the medium of bevel wheels 17, 18 and 19, this movement being trans-
mitted by other bevel wheels 20 to the screws 15 carrying the screw nuts 14 which
constitute the bearings for the shaft 9 of the roller 8 (Figs. 4, 5) two brackets 11
(Fig. 5) fixed to the pipe 6 serving to support the adjusting device.
A
As the dredger is moved along it may come into contact with a portion of
ground or other obstacle presenting such resistance as to cause the pipe 6 to rise.
To avoid this, a rigid rod 25 (Fig. 4) may be fixed to the dredger, which rod bears
against the pipe 6 through the medium of an anti-friction roller 26. This rod
carries a rack bar which gears with a pinion 27 rotated by a crank-handle.
roller 28 serves as a guide for the aforesaid rod 25 and a yoke or bracket 29
ensures its vertical position. A ratchet wheel with pawl (not shown in the
drawing) mounted on the shaft of one of the pinions 27 prevents the rod 25 from
accidentally rising.
This apparatus may also serve for elevating the pipe 6, for this purpose all that
is necessary is to add to the bottom of the aforesaid yoke or bracket 29 a second
roller 30 which bears against the under side of the pipe 6.
To obtain a better distribution of the stress, two similar apparatus, placed
symmetrically, relatively to the axis of the boat, may be provided, with their
corresponding anti-friction rollers working on one and the same shaft.
The connection 22 which permits of the suction pipe being lifted, may be of
any suitable construction and the mechanical arrangements which allow of
controlling the movement of the connection 22 or of the ascending and descending
movements of the drum or roller 8 which rearwardly adjusts the working spout
of the suction pipe may be modified and the suction pipe may vary in shape and
section according to the nature of the work.
may place the drum which regulates the height of the inlet of the pipe from
the bottom before the said pipe if desired and this arrangement is shewn with its
mode of operation in dotted lines in Figs. 1, 4 and 5. Or such adjustment may
be obtained by means of two drums, one in front and the other behind the suction
pipe.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is

page_text: connected to the ground or soil comprising a suction-pipe so arranged as to act
upon a constant thickness of the material to be dredged, by the action of support-
ing devices formed by the combination of a connection and of a supporting roller
or drum the shaft of which can be raised and lowered while in motion,
substantially as hereinbefore described.
2. In a suction dredger, in which the height of the working part of the suction
pipe is adjusted, while in motion, the arrangement wherein the suction pipe is in
compression when the apparatus is at work, substantially as hereinbefore
described with reference to Figures 1 and 2 of the accompanying drawings.
3. In a suction dredger, in which the height of the working part of the suction
pipe is adjusted, while in motion, the arrangement wherein the suction pipe is in
tension when the apparatus is at work, substantially as hereinbefore described
with reference to Figures 4 and 5 of the accompanying drawings.
Dated this 8th day of November 1897.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.