A NEW OR IMPROVED PNEUMATIC STEAM DREDGING MACHINE
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by William Edward Gedge at the
Office of the Commissioners of Patents, with his Petition, on the 19th
September 1866.-A communication from abroad by Emilio Musciacco,
of Brindisi, Italy.
I, WILLIAM EDWARD GEDGE, of the Firm of John Gedge and Son, of No. 23,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Patent
Agent, do hereby declare the nature of the said Invention for "A NEW OR
IMPROVED PNEUMATIC STEAM DREDGING MACHINE," (a communication to me from
abroad by Emilio Musciacco, of Brindisi, Italy), to be as follows:-
The improved dredging machine, the subject of this Invention, is composed
of a covered hopper closed hermetically and air-tight, with a sluice or trap at
the bottom inside a boat, hereafter termed the hopper boat. The hopper is
furnished with a cock, by which a jet of steam compressed by several atmo-
spheres, and coming through tubes from a steam generator carried on a second
boat is admitted into it. As the steam enters the air escapes through a pipe,
the lower end of which should reach the lowest point or that nearest the bottom
of the hopper, so that when it is seen that steam is fairly issuing from the
summit it may be concluded that the hopper is perfectly full of steam, and
consequently sufficiently free from air for the work; this pipe is also provided
with a tap. Pump tubes for drawing and picking or dredging up by suction
from the bottom of the water are fitted in boxes to openings in the hopper,
and are removeable at pleasure; they are furnished with gutta percha tubing,
which comes over the joint after the tube is set in the box, and carry a small

page_text: chain or cord which is fixed by one end to the side of the hopper, and serves
to keep them in the coupling boxes without however hindering their move-
ments. A semisphere at the lower end of a tube is enclosed in each pump
tube, but so that it cannot escape by the orifice, which is of a dimension such
as will permit the tube to move in an oblique and vertical direction. The
base of the pump tube is in form of a square truncated pyramid furnished with
a covering or coupling joint of canvas, which serves to partly intercept the
passage of water to its upper orifice. Two beams project from the poop of
the steamboat, and to these the upper part of the pump or suction tubes is
tied by a chain or cord, so that they are held suspended to their corresponding
or respective beams when removed from the box of the hopper. A fastening
in shape of an inverted wedge, covered so as to close hermetically, and working
by means of a turnscrew or wing nut at the top of the screw rod which upholds
it, serves to open or close the sluice or trap at the bottom of the hopper. An
opening is left in the hopper sufficiently large to permit a person to descend
into the interior in case of necessity; its fastening is also cuneiform, and is
sufficiently lined and covered with gutta percha to prevent the passage of air.
The generating boiler on the steamboat furnishes steam to the hopper boat by
means of elbow pipes or tubes bending in every direction to accommodate
themselves to the position of the hopper, and fixed to the cock by which the
steam is admitted to the hopper. The hopper boat might, if desired, carry its
own steam boiler, and thus work without depending upon another steam-
boat.
The working of the apparatus is as follows:-The steamboat is anchored
at the spot which is to be dredged, and very near and astern of this boat is
placed the hopper boat. The steam from the first passes into the interior of
the latter by the transmission pipes, and when the filling of the hopper with
steam is made manifest by the tube through which the air escapes its tap is
closed. In a few instants the condensation of the steam takes place, and a
vacuum is formed in the hopper; then by the excess of the weight of the
column of outer atmospheric air which naturally presses on the surface of the
water it happens that the moveable molecules which are in front of the mouths
or suckers of the suction tubes moved by this pressure advance in the direction
in which there is no resistance, rise in the tubes, and pour into the hopper
until concurrence of forces, and consequently until the hopper is filled; but
as the mouths or suckers completely touch the surface of the muddy or slimy
bottom the small fetid particles or molecules are the first to rise and ascend
the tubes, and consequently the first to be removed, then the heavier sands
which are in a deeper layer rise, and, lastly, part of the mixed gravel rises,

page_text: and thus the cleansing and deepening of the bottom is effected. The hopper
boat being thus loaded, the chains or cords are detached, the flexible coverings
of the joints are folded on each other, and the tubes are drawn out of the
openings and left suspended to the beams of the steamboat, to which they
are attached. The loaded hopper then leaves for the spot where it is to
discharge its load, and another approaches and is loaded in a similar manner
to the first. From on board the steamboat, and by means of ropes attached
to a capstern the suckers are lifted from one place and carried to another,
which is to be cleansed or deepened. The hopper then approaches, the tubes
are let in, the joints are covered with the flexible tubing, the chains and ropes
are attached, the steam conducting tubes are fitted to the taps, and this being
done another operation like the preceding is commenced always by causing
compressed steam to enter the hopper, and so on.