Improvements in Discharging Grain from Vessels.
Year: 1890

page_text: Date of Application, 29th July, 1890
Complete Specification Left, 29th Apr.. 1891-Accepted, 6th Jun',
1891
PROVISIONAL SPECIFICATION.
Improvements in Discharging Grain from Vessels.
I, FREDERIC ELIOT DUCKHAM of Millwall Docks, Engineer, do hereby
declare the nature of this invention to be as follows:-
My invention relates to an improved method of and apparatus for discharging
grain cargoes from ships or barges into bins or other receivers on the wharf,
and it has for its object to enable this operation to be accomplished more
expeditiously and with the assistance of less hand labour than is possible with
the means at present available for the purpose. The invention is specially
applicable for discharging cargoes composed of different sorts or qualities of grain
shipped in superposed layers separated only by a sheet of canvas as is commonly
practised, which the mechanical appliances now used cannot effectually deal with
so as to keep separate the different kinds or qualities of grain.
My invention comprises a mode of conveying the grain by the carrying power
of a current of air in which the individual grains may be said to be suspended
or floating so that all liability of choking the apparatus is avoided, together with
means or apparatus whereby the current of air is produced and controlled so
that the working of the apparatus is rendered as far as possible automatic.
The apparatus comprises one or more air tight receivers mounted upon a
carriage so as to be transportable on the wharf and connected with an air
pump or other exhauster whereby a partial vacuum is formed in the receiver under
the control of a valve or valves operated by counterbalance and tumbler mechanism
set in action by the weight of the charge in the receiver, so that when the
receiver is filled the connection with the air- exhauster is cut off and air admitted
and a valve at the lower part of the receiver opened to allow the charge of grain
to flow out by gravity into the bin or receptacle destined to receive it. Each
receiver is connected at top by a conveying pipe extending from the receiver over
the ship or barge with a pendant flexible pipe capable of passing through, a
hatchway and of being readily swung about in the hold of the vessel so as to take
the grain from any point therein thus avoiding the necessity of hand labour for
shovelling the grain towards the hatchway. This pendant pipe is open at the
lower end which is provided with means whereby when the end of the pipe is
buried in the grain, a constant admission of air to the pipe from above the cargo
is ensured to maintain a sufficient carrying current for the grain, and avoid choking
the pipe which would arise by the forcing into it of a compact mass of grain.
Two receivers would generally be employed, the valves controlling their various
connections being so arranged and combined with the valve operating apparatus
that the one receiver is emptying whilst the other is filling, and so on alternately.
Dated this 20th dow of July 1890
COMPLETE SPECIFICATION.
Improvements in Discharging Grain from Vessels.
I, FREDERIC ELIOT DUCKHAM, of Millwall Docks, London, Engineer, do
hereby declare the nature of this invention and in what manner the same is to be
5 performed, to be particularly described and ascertained in and by the following
statement :-
My invention relates to apparatus for use in conveying grain and other matters

page_text: (in or between warehouses, granaries, ships, barges, bins, or other receivers) by the
carrying power of a current of air, and particularly for discharging grain in bulk
from awkward and confined places on board ship or for discharging and keeping
separate different parcels of grain shipped in superposed layers separated only by
mats, canvas, or boards, as is commonly practised.
My invention relates, first, to the means whereby the admission of air in sufficient
quantity to the mouth of the suction pipe is ensured in order that the individual
grains may be suspended or caused to float in the current and avoid choking of
the suction pipe.
The invention also comprises the combination, with the suction pipe provided
with such air inlet and with the exhausted receiver, of discharging apparatus
whereby the grain transported and deposited by the carrying current is discharged
without the admission of air being permitted at this point in such quantity as to
destroy the partial vacuum created by the exhaust apparatus.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein Figure 1 is a general view of the apparatus, as applied to
work on board ship, and Figure 2 is a detail section of the suction nozzle.
Figure 3 is an elevation, partly broken away, of the delivery apparatus.
Figure 4 is a section of the hopper, and Figure 5 is a detail.
The same letters of reference indicate the same parts in all the figures.
A is the suction pipe connected to the chamber B and terminating in a suction
or inlet nozzle C, the part of the pipe which is to be led through the ship's
hatchway or side port being flexible and prevented from collapse under atmos-
pheric pressure by a wire coil in the thickness of the material of the tube. The
nozzle C is surrounded at a distance by an outer sleeve D terminating at its lower
end at such a distance above the level of the inlet mouth that a straight line 1-1
radial to the vertical axis of the nozzle and parallel to the angle of repose 2-2
of the grain and touching the edge of the sleeve D will intersect the side of the
nozzle at a given distance (say half or three quarters of an inch more or less)
above its edge, such that there will always be a constant depth of grain through
which the air passing from the sleeve to the nozzle must force itself in order that
the air shall carry along with it the particles of grain constantly flowing down and
intervening between the apertures of the sleeve and nozzle. The depth of the
constantly renewed grain so interposed cannot, however, be exceeded whatever
may be the depth of immersion of the nozzle and sleeve so that the air will
always be in sufficient quantity to provide for the efficient carriage of the grain.
The relative proportion of the sleeve D to the nozzle C should be such that from
twenty-two to twenty-four volumes of air at atmospheric pressure will be admitted
for each volume of grain so as to maintain a sufficient carrying current and prevent
choking of the pipe which would arise by forcing into it a more or less compact
mass of grain. The sleeve is carried up a sufficient height so that its upper open
end will never be immersed in, or obstructed by, the grain. The lower part of
the sleeve need only be of annular form and the upper part may be in the form of
a pipe or pipes. Any suitable arrangement of tackle may be employed for sup-
porting and counter-weighting the pendent nozzle; so that it may be swung about
or traversed where required, and be readily raised and lowered. E is a cage or
fender which may be applied to the lower end of the inlet nozzle C to keep
mats, etc., dividing the parcels of grain, beyond the influence of the suction whilst
allowing the grain to pass freely. In moving the inlet nozzle from place to place,
a flexible disc of india rubber may be temporarily applied over the mouth of the
nozzle to prevent loss of vacuum.
The part of the apparatus next about to be described may be mounted upon a
barge or other vessel or upon a wheeled or fixed structure upon the wharf or
elsewhere, according as the apparatus is to be used for transferring grain between
ships or other conveyers and warehouses or granaries. The chamber B into which
the suction pipe A leads tangentially (by a pipe section A' of gradually enlarged
diameter in order to reduce the velocity of the grain) may be in the form of a

page_text: conical hopper and is provided with a dome B' connected by a pipe F provided
with a stop valve, with exhausting apparatus of any suitable kind by which a
partial vacuum is maintained. Beneath the chamber B is mounted to rock upon a
horizontal axis a twin receiver H H the upper face I of which is curved to an
arc struck from centre h so as to make a comparatively air-tight joint, in the
manner of a slide valve, with the correspondingly curved mouth of the conical
hopper B. In this valve face are two apertures leading to the respective
receivers H H which apertures are, by the oscillating motion of the twin receiver,
made to alternately coincide with the discharge aperture of the hopper B so that
the one receiver will be filling whilst the other is discharging, and so on alternately.
The part of the valve face intervening between the apertures i should have
sufficient lap to close the discharge orifice of the hopper and prevent direct com-
munication between the apertures i i¹ during the oscillating motion. Each receiver
has a sloping bottom, to facilitate discharge and provided with outlet flaps k
opening outwards and held closed by external air pressure against the admission of
air during the filling of the receiver. The oscillating motion of the twin receiver is
controlled by weighing apparatus, whereby a regulated quantity of grain is delivered
at the discharge of each receiver. Said mechanism consists of a pair of steel-
yards K K (one for each direction of motion) centred on axes k² and provided
with jockey weights ³, for regulating the resistance of the steelyards to the
average weight of the box-load of grain. To the short arms of the steelyards
are pivoted pendent catches and upon one or other pair of these catches rest lugs m
fixed to the tumbling box, in order to support it in position during the filling of
the corresponding chamber. These catches are connected by slotted links n to a
pin n' on the frame whereby when the load of the one chamber (H' for example)
overcomes the corresponding steelyard K' the catch will be drawn out of
engagement with the lug m and the twin receiver will be caused by the pre-
ponderating weight of the load to fall over to the other side, as shewn in dotted
lines, thus bringing the other chamber into position to be filled, and by discon-
necting the full receiver from the exhaust allowing its discharge flap to be pressed
open by and discharge the grain. To prevent shock by the too sudden oscillation
of the twin receiver its motion is checked by a dash-pot or cataract cylinder N,
whose piston is connected to the receiver, as shewn.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a pneumatic grain-conveying apparatus, the combination, with the grain
inlet nozzle of the suction pipe, of a circumferential air passage opening above the
level of immersion of said nozzle and terminating just above the level of the inlet
orifice so as to admit to the grain inlet orifice a carrying current of air along with
the grain drawn therein by the vacuum, as specified.
2. In a pneumatic grain-conveying apparatus, the combination, with the grain
inlet nozzle of the suction pipe, of a circumferential air passage formed by a sleeve
surrounding the nozzle, opening above the level of immersion of said nozzle and
terminating at such a height with regard to the inlet orifice of the nozzle that a
radial line touching the ends of the nozzle and sleeve will make a lesser angle
with the axis of the nozzle than the angle of repose of the grain, substantially as
specified.
3. In a pneumatic grain conveying apparatus, the combination, with a pendent
inlet nozzle provided with a circumferential air passage, as described, the suction
or conveying pipe and the exhausted hopper receiver, of the discharging receiver
divided into two compartments having inclined floors and self-closing discharge
flaps and adapted to rock on a horizontal axis and thereby to automatically make
connection alternately between the one and the other of its chambers and the said
hopper for the purpose of discharging the grain in measured quantities, without
admitting air, as specified.

page_text: 4. In a pneumatic grain conveying apparatus, the combination, with the twin
receiver adapted to rock on a horizontal axis and thereby to make connection
alternately between the one and the other of its chambers and the hopper above,
of automatic releasing mechanism consisting of counter-weighted levers, latches
connected to said levers and adapted to automatically engage with and support
the rocking receiver, and of connections between the latches and the weighted
arms whereby the motion of the latter under the preponderating weight of the
load in the corresponding chamber of the receiver will cause the latches to be
disengaged and allow the receiver to fall over to the other side so as to put the
empty chamber in communication with the hopper and allow the full chamber to
discharge its load, substantially as specified.
F. E. DUCKHAM.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.