Year: 1887

page_text: Date of Application, 16th Feb., 1887
Complete Left, 21st Sept., 1887.
Complete Accepted, 21st Oct., 1887.
I, DAVID THOMAS FENDER of No. Delahay Street, Westminster in the County
of Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to hydraulic dredging apparatus wherein the current of water
and consequent scour produced by the suction tube of a pump situated close to the
bottom to be excavated causes the soil to be drawn together with the water up the
suction tube. My present improvements consist in jointing to the end of the suction
tube an attachment of an inverted trough shape lying with its open side upon the soil
to be excavated, and having its free end also open, so that the scouring action produced
by the suction of the pump will be confined to that part of the soil enclosed by the
attachment and situated in front of its open end, and thus the effectiveness of such
action will be greatly increased.
Fig. 1 of the accompanying drawing shews by way of example a side view of one
form of such attachment, Figure 2 shews a plan of the underside and Fig. 3 a cross
section at xx.
A is the suction pipe, to which the attachment C is connected by a universal joint B
or by other suitable means. The attachment C is open on its underside from a to b
and it is also open at the end a so that the water drawn in through such open end and
passing along the enclosed surface of the soil will produce a very effective scour that
will more or less rapidly remove the soil at the end of and underneath the attachment,
which will consequently gradually sink down into the dotted position, turning on its
joint B. The undersurface of C may be curved either at each'end only as shewn, or along
its whole length, and if the ground is of a soft nature, it may be provided with flanges,
as shewn in dotted lines at c Fig. 3 to afford it sufficient support. A ring or hook D
is provided for raising the attachment C when required.
DL: 10th 1
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ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Hydraulic Apparatus for Dredging Operations.
I DAVID THOMAS FENDER of No. 1 Delahay Street, Westminster in the County
of Middlesex, 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 :-
My invention relates to hydraulic dredging apparatus wherein the current of water
and consequent scour produced by the suction pipe of a pump situated close to the
bottom to be excavated causes the soil to be drawn together with the water up the
suction pipe. My present improvements consist in jointing to the end of the suction
pipe an attachment of an inverted trough shape lying with its open side upon the soil
to be excavated and having its free end also open, so that the scouring action produced
by the suction of the pump will be confined to that part of the soil enclosed by the
attachment and situated in front of its open end and thus the effectiveness of such
action will be greatly increased.
Figs. 1 to 8 on sheet I of the accompanying drawing shews one form of the
hydraulic dredging apparatus constructed according to my invention. Fig. 1 is a
longitudinal section, Fig. 2 a half plan of the upper side, Fig. 3 a half plan of the
underside. Fig. 4 an end view, Figs. 5, 6 and 7 cross sections respectively on
lines, y y, and z z, and Fig. 8 the end view of the flanged connection with the ball
and socket joint of the suction pipe; in the case of a flexible connection being used,
this would merely be a spigot end. A is the suction pipe, which is connected by a
ball and socket or other flexible joint B to the trough shaped attachment C which is
open at the under side, and at the free end, a grating D being secured over these
surfaces in cases where the soil to be excavated contains hard masses of a size which
it is desirable to keep out of the suction pipe. The sectional area at the end a is made
less than that at the end b, so that there is a greater scour produced at a than at b,
by the suction up the pipe A. In consequence hereof the soil will be excavated more
rapidly at the free end of the apparatus than at the other end, causing it to sink more
or less rapidly from the position shewn in full lines at Fig. 1, which it occupies on
commencing operations, into an inclined position such as that shewn in dotted lines,
the degree of inclination being dependent on the speed at which the suction pipe A is
drawn along the surface to be dredged, such speed being regulated in the usual way
by the action of winches on board the dredger or by other suitable means.
a limited depth is required to be maintained both the apparatus and the suction
pipe may be suspended by ropes or chains attached, in the case of the apparatus
at C Figs. 1 and 4 and in the case of the suction pipe at any convenient point of its
length.
Where
Figs. 1, 2 and 3 on sheet II shew respectively a side view, a plan and a section on
line xx, of another construction, in which the apparatus C, instead of having parallel

page_text: sides as in the first arrangement, has curved sides the opening at a being of smaller
width and consequently of less area than the sectional area of the other part of the
apparatus so as to obtain the increased scour.
The apparatus is here shewn without the grating and the underside is curved at the
end; if the ground is of a soft nature it may be provided with external flanges as
indicated in dotted lines at E Fig. 3 to afford it sufficient support. The parts
are otherwise the same as before described and are indicated by the same letters of
reference.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed, I declare that what I claim is :—
The use in combination with the suction pipe of hydraulic dredging apparatus of
an attachment of an inverted trough shape open at one end connected by a flexible or
articulated joint at the other end to the suction pipe, and adapted to lie with its open
under surface upon the soil to be excavated, substantially as and for the purposes
herein described.
ABEL & IMRAY,
Agents for the Applicant.