Improvements in Dredging Apparatus."
Year: 1898

page_text: *Reprinted
as amended in accordance with the decision of the Comptroller General
dated the 30th day of July 1903.
66
PROVISIONAL SPECIFICATION.
Improvements in Dredging Apparatus."
1, Orto FRÜHLING, of No. 5, Monument Platz, Brunswick, Germany, Civil Engineer
to the Government, do hereby declare the nature of this invention to be as follows:-
Dredging apparatus operating by suction, as hitherto employed, that is to say, in
which the bottom is simply sucked up through a tube with or without cutting devices,
have the disadvantage that the quantity of water drawn in with the materials cannot
be regulated according to requirements, and that the water in flowing with great
violence from all sides towards the tube opening, thereby loosens the bottom and
carries this with it into the tube, thus producing large holes and unevenesses in the
surface of the bottom, and lastly, that the cutting appliances hitherto applied to the
opening of the dredging tube for the purpose of cutting into heavy soils, so as to
loosen them for enabling the water currents to carry them off, only operate in an
imperfect manner.
The chain bucket dredging machines, which scoop up the bottom in the usual
manner and supply the charges to pumping and mixing apparatus, for farther
transport, do not suffer from the two last named disadvantages, but they also cause
the first named defect, and are more complicated in construction and consequently
more expensive to work than the suction dredging apparatus.
The present invention has for its object to adapt the advantages of the chain
bucket dredging machine to the suction dredger, and to obviate the disadvantages of
the latter, while retaining the simplicity and cheapness of the old mode of working.
For this purpose the dredging apparatus is provided with a scoop shaped dredger
head the construction of which forms the subject of the present invention.
I will describe the apparatus with reference to the accompanying drawings in which
Figure 1 shews a front view, Figure 2 a longitudinal section, the left-hand side being
taken on line s Figure 3, and the right-hand side on line - Figure 4,, Figure 3
shews a cross section at no Figure 2, Figure 4 a cross section at p-q Figure 2, and
Figure 5 a plan view in the direction F Figures 3 and 4.
The action of the apparatus is as follows: The dredger head is lowered from the
dredger barge or vessel on to the bottom to be excavated, and is then drawn or forced
forward by the dredging engine. The front part A of the head is caused by its
weight and position to penetrate into the ground by means of a cutting edge formed
round the bucket. the edge being if necessary provided with points or coulters to
facilitate this. The cutting edge thus separates the part of the soil to be dredged
from its bed, and the pressure of the uncut soil in front of the scoop forces the cut
portion into the head as this is drawn forward. The soil is therefore no, longer sucked

page_text: roff the bottom as heretofore but is dug out as with chain bucket dredgers, so that
the production of holes and mounds is prevented.
The excavated soil within the head is here reduced to small fragments at the back
part B, and is there sufficiently mixed with water to enable it to be sucked out of the
head by a pump, and forced forward thereby.
In order to enable the quantity of water employed for such reduction and mixing
of the soil to be effectually regulated according to the nature of the bottom, and to be
limited to the minimum necessary quantity, the water is not drawn in in an uncontrolled
manner through the mouth of the scoop, this mouth being practically closed against
the surrounding water, and the mixing water is supplied through special tubular
conduits the supply through which can be regulated.
For this purpose the upper part of the front face of the dredger head is closed by a
plate a-b.
In the forward motion of the head against the bottom to be dredged, a portion of
the soil piles itself up against this plate in front of the head, as indicated at
Figures 3 and 4, the action being the greater, the quicker is the forward motion of
the head. By the inclination of the plate, this soil is at the same time forced
downwards towards the opening of the head, and it thus operates in combination
with the plate a-b to prevent the ingress of the surrounding water.
The soil thus passes into the inner space B without being materially mixed with
water, and there has the necessary quantity of water added to it for enabling it to be
worked up and drawn off by the pump, this supply being effected either by a
regulatable water pressure supply pipe C or by a suction supply pipe D.
This is put
in action by the pump that sucks off the dredger sludge by means of a tube E, thus
drawing in water through D, which is led up to near the surface of the water, where
its inlet opening is provided with slides flaps or valves so as to enable the operatives
on the dredger to regulate the water admitted through it into the dredger head,
according to the nature of the bottom and other circumstances.
The reduction and mixing of the soil within the part B can be effected by any
known devices suitable for the purpose, namely, either by means of water under
pressure entering through openings e from the supply tube C in the form of strong
jets that break up the soil, or by means of screw blades g, or stirring arms & mounted
on a revolving shaft, the action of which can be increased by providing fixed cutters
or projections i. The reduction can also be effected by the supply indicated by
arrows produced by the suction through D, the water being caused by guide
blades k, Figures 1 and 5, to flow through the greater part of B and consequently to
stir up the soil therein, before passing off through the suction at E. The screw 'or
stirrer shaft is driven either by means of chain wheels m situated, either open or
enclosed, on the dredger head, or by means of pressure water acting on a turbine
wheel, or by electricity in any suitable known manner.
The screw shafts also serve to assist the motion of the sludge towards the suction
discharge E.
A preliminary reduction of the soil and a separation of stones &c. therefrom can
also be effected by the provision of knives, coulters, and gratings, applied in the
opening of the bucket or scoop.
It will be seen that by applying the above dredger heads either singly or two or
more in combination, the apparatus can be adapted to operate on beds of very
variable kinds, while at the same time the expenditure power required for the
dredging operations is limited to that which is exactly necessary.
The guiding of the dredger head from the dredger barge can be effected in various
ways.
If the dredging is to be effected with a to and fro forward motion of the dredger
vessel, the head is guided by rigid framed bars pivoted to the barge, the 'motion of
which is effected in the usual manner. The head may be made rotatable, so as to be
reversed when the direction of motion of the barge is changed. In this case two
fixed dredger heads may be provided at the end of the guide rods, one of which is
put in action when dredging to the right hand, while the other is put in action when

page_text: dredging to the left hand.
The suction tube E, the supply tubes C and D and the
actuating mechanism are carried by the guide frame.
If a simple bank has to be removed by dredging, the dredger head is attached by
a fixed or moveable guide frame to the barge and is drawn to and fro by the latter.
The dredging vessel is either hauled along by chains, or is propelled by screw
propellers, the bank being dredged away in strips.
If the dredging is to be effected at sea during flood and ebb tide, the dredger head
is hung in chains, and is drawn along thereby, by the vessel.
The suction and supply tubes are carried between the chains.
The connection of the suction tubes with the pumps is effected by means of
articulated or ball and socket union joints. The pumps which suck off the dredged
sludge from the head either force it in the known manner through floating conduit
tubes directly to the deposit ground, or they discharge into hoppers or receptacles in
barges or the like.
The latter is rendered practicable with the use of the described dredger head even
with very loose soil or silt because the addition of water can be regulated and limited
to the minimum quantity necessary.
The guide bars or frames and conduit pipes can be attached to the dredging vessel
in any suitable known manner, and the apparatus can be combined with any existing
construction of dredging vessels.
Dotad this 0th day of nation 1000
ABEL & IMRAY,
Agents for the Applicant.
.
1, OTTO FRÜHLING, of No. 5 Monument Platz, Brunswick, Germany, Civil Engineer
to the Government, 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:--
in
Dredging apparatus operating by suction, as hitherto employed, that is to say,
which the bottom is simply sucked up through a tube with or without cutting devices
have the disadvantage that the quantity of water drawn in with the materials cannot
be regulated according to requirements, and that the water, flowing with great violence
from all sides towards the tube opening, loosens the bottom and carries this with it
into the tube, thus producing large holes and unevenesses in the surface of the bottom,
and lastly, that the cutting appliances hitherto applied to the opening of the dredging
tube for the purpose of cutting into heavy soils so as to loosen them for enabling the
water currents to carry them off only operate in an imperfect manner.
The chain bucket dredging machines, which scoop up the bottom in the usual
manner and supply the charges to pumping and mixing apparatus, for farther trans-
port, do not suffer from the two last named disadvantages, but they also cause the
first named defect and are more complicated in construction and consequently more
expensive to work than the suction dredging apparatus.
The present invention has for its object to adapt the advantages of the chain bucket
dredging machine to the suction dredger, and to obviate the disadvantages of the
latter, while retaining the simplicity and cheapness of the old mode of working.
For this purpose the dredging apparatus is provided with a scoop shaped dredger
head the construction of which forms the subject of the present invention.
I will describe the apparatus with reference to the drawings accompanying my
Provisional Specification in which Figure 1 shews a front view, Figure 2 a longitudinal
section, the left hand side being taken on line -s Figure 3, and the right hand side

page_text: on line tu Figure 4, Figure 3 shews a cross section at n o Figure 2. Figure 4 a
cross section at pq Figure 2, and Figure 5 a plan view in the direction F Figures 3
and 4.
The action of the apparatus is as follows. The dredger head is lowered from the
dredger barge or vessel on to the bottom to be excavated and is then drawn or forced
forward by the dredging engine. The front part A of the head is caused by its
weight and position to penetrate into the ground by means of a cutting edge formed
round the bucket, the edge being if necessary provided with points or coulters to
facilitate this. The cutting edge thus separates the part of the soil to be dredged
from its bed, and the pressure of the uncut soil in front of the scoop forces the cut
portion into the head as this is drawn forward. The soil is therefore no longer sucked
off the bottom as heretofore but is dug out as with chain bucket dredgers, so that the
production of holes and mounds is prevented.
The excavated soil within the head is here reduced to small fragments at the back
part B, which forms a mixing chamber in which by the devices provided for that purpose
the soil and is there sufficiently mixed with water to enable it to be sucked out of the
head by a pump and forced forward thereby.
In order to enable the quantity of water employed for such reduction and mixing
of the soil to be effectually regulated according to the nature of the bottom and to
be limited to the minimum necessary quantity, the water is not drawn in in an
uncontrolled manner through the mouth of the scoop, this mouth being practically
closed against the surrounding water, and the mixing water is supplied through
special tubular conduits the supply through which can be regulated.
For this purpose the upper part of the front face of the dredger head is closed by a
plate a b.
In the forward motion of the head against the bottom to be dredged a portion of
the soil piles itself up against this plate in front of the head, as indicated at Figures 3
and 4, the action being the greater, the quicker is the forward motion of the head.
By the inclination of the plate, this soil is at the same time forced downwards towards
the opening of the head, and it thus operates in combination with the plate ab to
prevent the ingress of the surrounding water.
This arrangement constitutes the essential feature of the invention by which it is
distinguished from similar constructions heretofore proposed. In the latter the aim
has always been while scooping up the soil with a dredger like action, to cause such
loosened material to be sucked into the head by the aid of a large body of water, for
which purpose the opening was made as large as possible and was provided in front
with a stirring or cutting device for mixing as much soil as possible with the large
body of water drawn in, such for example as described in the specifications to English
Patent No. 19165 of 1893 and U.S. Patent No. 598982.
It will be seen that with that method of operating the great disadvantage arises
that a comparatively large body of water is uselessly raised in order to effect the
raising of a comparatively small quantity of the loosened bottom. By the present
improved mode of operating on the other hand, the inrush of water through the
mouth of the dredger head is practically entirely prevented by causing the cutting
device to loosen such a quantity of soil in front of the dredger head that it accumu-
lates against the plate ab thereof, entirely closing the comparatively small opening,
through which consequently only the loosened soil mixed with a little water enters
the space B of the head in order there to be thoroughly reduced and mixed with only
such a regulated quantity of water, supplied separately as will form a sludge that can
be drawn up the conduit by the sucking action produced by a pump or exhaust fan,
the said water supply being effected either by a regulatable water pressure supply
pipe C or by a suction supply pipe D. This is put in action by the pump that sucks
off the dredger sludge by means of a tube E thus drawing in water through D, which
is led up to near the surface of the water, where its inlet opening is provided with
slides flaps or valves so as to enable the operatives on the dredger to regulate the
water admitted through it into the dredger head, according to the nature of the
bottom and other circumstances.

page_text: The reduction and mixing of the soil within the part B can be effected by any
known devices suitable for the purpose, namely, either by means of water under
pressure entering through openings from the supply tube C in the form of strong
jets that break up the soil, or by means of screw blades g or stirring arms h. mounted
on a revolving shaft, the action of which can be increased by providing fixed cutters
or projections i., The reduction can also be effected by the supply indicated by
arrows produced by the suction through D, the water being caused by guide
blades k, Figures 1 and 5, to flow through the greater part of B and consequently to
stir up the soil thereon, before passing off through the suction at E. The screw or.
stirrer shaft is driven either by means of chain wheels m situated, either open or
enclosed, on the dredger head, or by means of pressure water acting on a turbine
wheel, or by electricity in any suitable known manner.
The screw shafts also serve to assist the motion of the sludge towards the suction
discharge E.
A preliminary reduction of the soil and a separation of stones &c. therefrom can
also be effected by the provision of knives, coulters, and gratings, applied in the
opening of the bucket or scoop.
It will be seen that by applying the above dredger heads either singly or two or
more in combination, the apparatus can be adapted to operate on beds of very variable
kinds, while at the same time the expenditure of power required for the dredging
operations is limited to that which is exactly necessary.
The guiding of the dredger head from the dredger barge can be effected in various
ways.
If the dredging is to be effected with a to and fro motion of the dredger vessel, the
head is guided by rigid framed bars pivoted to the barge, the motion of which is
effected in the usual manner. The head may be made rotatable, so as to be reversed
when the direction of motion of the barge is changed. In this--euse Or two fixed
dredger heads may be provided at the end of the guide rods one of which is put in
action when dredging to the right hand, while the other is put in action when
dredging to the left hand. The suction tube E, the supply tubes C and D and the
actuating mechanism are carried by the guide frame.
If a simple bank has to be removed by dredging, the dredger head is attached by a
fixed or moveable guide frame to the barge and is drawn to and fro by the latter.
The dredging vessel is either hauled along by chains or is propelled by screw
propellers, the bank being dredged away in strips.
If the dredging is to be effected at sea during flood and ebb tide, the dredger head
is hung in chains and is drawn along thereby, by the vessel.
The suction and supply tubes are carried between the chains.
The connection of the suction tubes with the pumps is effected by means of
articulated or ball and socket union joints. The pumps which suck off the dredged
sludge from the head either force it in the known manner through floating conduit
tubes directly to the deposit ground or they discharge into hoppers or receptacles in
barges or the like.
The latter is rendered practicable with the use of the described dredger head even
with very loose soil or silt because the addition of water can be regulated and
limited to the minimum quantity if necessary.
The guide bars or frames and conduit pipes can be attached to the dredging vessel
in any suitable known manner, and the apparatus can be combined with any existing
construction of dredging vessels.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that I make no claim
to the separate features of the apparatus described, but what I claim is:-
1. Dredging The herein described dredging apparatus consisting of a dredging head or
scoop so combined and arranged that firstly by means of part A similar to a dredger
bucket the bottom is dug out and supplied to the head in such manner that the loosened
soil in accumulating against the plate a 6 closes the opening so as to prevent any

page_text: detrimental inrush of water so that only the loosened soil enters the space B which
acts as a miring chamber whereby means of special reducing devices and by a
separate supply of water through conduit C or D the charge is reduced and mixed
with water, the resulting sludge being sucked off from the space B through conduits E
and conveyed wherever required, substantially as described.
2.--In-dredging--apparatus--such--as--is--referred--to-in-the-first-claim,--arranging--the
water supply-to-the-charge-within--the-chamber-B--so-that--it--ean--be-regulated--at
will-on-the-one-hand-by-se-construeting-the--dredger-head-as-to-prevent--the--ingress
of--water--through--its--front--opening,--and--on--the--other--hand--by-the-provision-of
special-pressure-or-suetion-water-supplies,-substantially-as-described.
3.--In combination--with-a--dredger-head--or--scoop--sneh--as--is--referred--te--in--the
preceeding-elaims, the--use-of-means--for-redueing-the-charge of soil;--for--mixing--the
same--with--water,--and--for--convoying--the-same-to-the---suction--discharge--E--sub-
stantially-as-herein-deseribed.
4: 2. Dredging apparatus combined and operating as herein described with reference
to the accompanying drawing.
ABEL & IMRAY
Agents for the Applicant.