IMPROVEMENTS IN DREDGING, AND IN THE MACHINERY, APPARATUS, OR MEANS EMPLOYED THEREIN.
Year: 1876

page_text: LETTERS PATENT to Edwin Powley Alexander, of 14, Southampton Buildings,
in the County of Middlesex, Consulting Engineer and Patent Agent, for
the Invention of "IMPROVEMENTS IN DREDGING, AND IN THE MACHINERY,
APPARATUS, OR MEANS EMPLOYED THEREIN.' A communication from abroad by
Emil Kaselowsky, of the City of Berlin, in the Kingdom of Prussia, Engineer,
"
PROVISIONAL SPECIFICATION left by the said Edwin Powley Alexander at
the Office of the Commissioners of Patents on the 15th February 1876.
EDWIN POWLEY ALEXANDER, of 14, Southampton Buildings, in the County of
Middlesex, Consulting Engineer and Patent Agent. "IMPROVEMENTS IN DREDGING,
AND IN THE MACHINERY, APPARATUS, OR MEANS EMPLOYED THEREIN." A communi-
cation from abroad by Emil Kaselowsky, of the City of Berlin, in the Kingdom of
Prussia, Engineer.
This Invention relates to an improved mode of and apparatus for dredging or
deepening harbours, rivers, canals, and lakes, and comprises the use of a vacuum,
a set of ploughs, rakes, spades, or other tools for loosening the soil, and a powerful
jet of water.
The operation of dredging is effected by loosening the soil and then sucking up
the same by the action of a vacuum into a suitable receiver, from which it is
periodically discharged into barges moored alongside the dredger. The dredger barge
itself carries a steam engine and boiler, by preference of the portable engine type,
also a large air-tight receiver for the reception of the dredged material. This
receiver is connected by a valve and steam pipe with the boiler of the engine, and
is also connected by another valve with a suction pipe working on a joint so as to
be free to rise and fall. The lower end of this suction pipe has a large mouth-piece
formed thereon, open on its under side, which rests upon the bed or surface to be
dredged, but closed at the top, sides, and ends.
Plough shaped or other tools may if desired be fitted to the interior of the said
mouth-piece for the purpose of loosening or breaking up the soil to be operated
upon; the slow travelling motion of the dredger, produced in any known manner,
causing the said tools to act upon the bed as they move along. A vacuum is
produced inside the receiver; by filling the same with steam from the boiler, and
then introducing one or more jets of cold water therein through pipes and valves

page_text: provided for that purpose so
as to condense the steam. So soon as a vacuum
commences to form the valve leading to the suction pipe is opened, and the soil is
at once sucked up into the receiver. In some cases, one or more powerful jets of
water supplied by a jet pipe and nozzle in connection with the air vessel of a pump
worked by the engine myy be employed inside the mouth-piece of the suction pipe
so as to operate in combination with the vacuum, thereby effectually stirring up
the soil and facilitating its suction into the receiver.
When the receiver is full its contents are discharged through a lateral opening
provided with a tight fitting door into a barge or other convenient receptacle
alongside. This discharge of the contents may in some cases be assisted or
expedited by steam pressure from the boiler, the said steam being condensed so as
to form a fresh vacuum as soon as it has expelled the contents of the receiver.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Edwin Powley Alexander in the Great Seal Patent Office on the 11th
August 1876.
"
EDWIN POWLEY ALEXANDER, of 14, Southampton Buildings, in the County of
Middlesex, Consulting Engineer and Patent Agent. "IMPROVEMENTS IN DREDGING,
AND IN THE MACHINERY, APPARATUS, OR MEANS EMPLOYED THEREIN. A communi-
cation from abroad by Emil Kaselowsky, of the City of Berlin, in the Kingdom
of Prussia, Engineer.
The said Invention relates to an improved mode of and apparatus for dredging or
deepening harbours, rivers, canals, and lakes, and comprises the use of a vacuum
chamber and suction pipe, also of a set of ploughs, rakes, or other tools attached to
the mouth-piece of the said suction pipe for the purpose of loosening the soil,
assisted or not by a powerful jet of water directed on to the soil within the said
mouth-piece.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the corresponding Figures.
Figure 1 of the Drawings represents a side elevation of the improved dredging
machine; Figure 2 is a transverse section of the same, corresponding to Figure 1,
and showing a mud barge connected therewith; Figure 3 is a plan of the dredger
corresponding to Figure 1; and Figure 4 is a section of a slightly modified
arrangement of vacuum apparatus.
A is a steam generator carrying a steam engine as in an ordinary portable
engine; B is an iron cylinder or vacuum chamber of suitable size; C is the suction
pipe with its mouth D, which is provided with ploughs, rakes, or other imple-
ments for loosening the soil. This pipe is moveable on the axis E, and has a T
projection or head working within a stuffing box which leads through the curved
pipe F into the cylinder B, with which it communicates through the large cut-off
valve G. A vacuum is produced in the cylinder B by first introducing, by means
of a valve, steam from the boiler A through the pipe J, thereby expelling the air
contained in the cylinder B through the cock K, and after closing the cock and
steam valve injecting a jet of water from the pump L and air vessel M so as to
condense the steam inside the vacuum chamber. After the vacuum guage has
indicated the existence of a vacuum the cut-off valve G may be opened, and the
slime or mud is then sucked in through the mouth-piece D and pipe C, the former
of which will be pressed down closely to the mud or slime by the action of the
hydrostatic pressure, and of the pressure of the atmosphere. During the action of
this pressure the dredger is slowly moved along at the rate of about 3 feet per second
in the direction of the arrow by means of the portable engine and winding appa-

page_text: ratus N acting upon a chain, which is fixed by anchors deposited some distance ahead
or astorn, the said chain running over the grooved wheels O, O. By this motion a
trench or furrow is made in the slime as broad as the mouth-piece, which as before
mentioned and shown in the Drawings is provided with plough-like tools for
loosoning the soil. In case the bottom of the port, canal, or other place to be
dredged should consist of a more resisting material, it is proposed to assist the
operation by stirring up the soil simultaneously by means of a powerful jet of
water, for which purpose a small pipe P is passed along the outside of the suction
pipe C, terminating at or near the centre of the mouth-piece D in a jet nozzle Q.
From the air vessel M, during the advance of the dredger, there is directed through
the jet nozzle a jet of water of about half an inch diameter, and with a pressure
of say from 4 to 5 atmospheres in order to break up, soften, and stir up the mass,
and thereby facilitate the lifting of the same. It will thus be seen that with this
dredger three different forces operate simultaneously and to the same purpose, viz.:
first, the vacuum in the cylinder B; secondly, the ploughs or other like implements
on the mouth-piece; and, thirdly, the jet of water of high pressure.
The cylinder B, having been filled or partially filled with mud in the manner
above described, the cut-off valve G is to be closed and the discharge aperture R at
the lower end of the cylinder (see Figures 2 and 3) to be opened. This aperture is
provided with a tight fitting strong lid lined with india-rubber or other suitable
material, and may be closed and opened at will by means of the hand wheel S. If
now the air be admitted by opening the upper cock K, the entire mass inside the
cylinder B will pass through the opening R into the mud barge, which for this
purpose is placed close to the dredger (see Figure 2). On the other hand, the
emptying of the cylinder B may be accelerated at will by introducing a steam jet
instead of air, which by its pressure will forcibly expel the mass. In the latter case,
as soon as the mass has been removed and the steam issues at R, the discharge lid or
lids may be closed, and the operation immediately repeated by condensing the steam
then contained within the cylinder B, as above described.
The apparatus herein-before described and illustrated at Figures 1, 2, and 3, of the
annexed Drawings, is designed more especially for raising slime and mud, and
consequently the inclination of the bottom of the cylinder B may be moderate.
Should the material however be of a firmer or harder nature then a greater inclina-
tion would be desirable. In this case a vessel of a form shown in vertical section
at Figure 4 would answer the purpose. Here the inclination of the bottom is about
1:2, the diameter of the vessel about 8 feet, and its height about 4 feet 8 inches.
a is the hand wheel for opening and closing the steam valve b, near which is a
similar valve for injecting the condensing water. c is a safety valve, which in
combination with the discharge opening R affords an outlet to the air. d is a
centre stay for supporting the inclined bottom. The cylinder or vacuum chamber
B may of course be constructed either of cast or of wrought iron, as preferred; C is
a portion of the suction pipe.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that I do not confine or restrict myself to the precise
details hercin shown and described, but what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First. The application and use to and in dredgers of a vacuum apparatus when-
arranged to operate substantially as herein-before described.
Secondly. The combination of the vacuum apparatus with a ploughing or soil
loosening apparatus attached to the lower end of the suction pipe, through which
the slime is raised when operating together substantially in the manner and for the
purpose herein-before described.
Thirdly. The application and use to and in dredgers of a stirring apparatus
consisting of a jet of water under high pressure applied at the lower end or

page_text: mouth-piece of the suction pipe, substantially as and-for-the -purpose herein-before-
described.
Fourthly. The combination of the said three contrivances in the construction of
dredgers, substantially as herein-before described and illustrated by the Drawings
hereunto annexed.
In witness whereof, I; the said Edwin Powley Alexander, have hereunto set
my hand and seal, this Ninth day of August, in the year of our Lord
One thousand eight hundred and seventy-six.
EDWIN P. ALEXANDER. (L.S.)