Improvements in Apparatus for the Pneumatic Conveyance of Grain and other Matters, and for Separating Dust from Air laden therewith.
Year: 1893

page_text: Date of Application, 22nd Feb., 1893
Complete Specification Left, 22nd Nov., 1893-Accepted, 13th Jan., 1894
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for the Pneumatic Conveyance of Grain
and other Matters, and for Separating Dust from Air laden
therewith.
I, FREDERIC ELIOT DUCKHAM of Millwall Docks, London, E., Civil Engineer
do hereby declare the nature of this invention to be as follows:-
:-
My invention relates to further improvements in the apparatus employed in the
pneumatic conveyance of grain or other granular or pulverulent matters in bulk
such as seeds, sand, small coal, and gravel, for example in and between warehouses,
granaries, and vessels, for which former Letters Patent were granted to me
respectively dated July 29th 1890, No. 11,884; February 24th 1891, No. 3376;
and April 17th 1891, No. 6665.
be
My first improvement relates to the pendent inlet nozzle which is inmersed in the
mass of the grain, etc., to be conveyed and it has for its object to enable the sleeve
which surrounds the nozzle (and through which the air necessary for the pneumatic
conveyance of the grain, etc., is supplied) to be adjusted in height with regard to the
nozzle. The proper relative position of the lower end of the sleeve with regard to
the mouth of the nozzle is dependent on the amount of vacuum employed and the
angle of repose of the grain or other matters to be conveyed, and as the angle of
repose varies according to the particular kind and condition of the grain or the
nature of the material it is necessary (in order that the proper proportions may
maintained between the volume of the carrying current of air and the grain or
other matters carried thereby) that provision should be made for adjusting the
height of the lower end of the air supplying sleeve relatively to the mouth of the
nozzle. For this purpose the sleeve instead of being fixed at a constant height with
regard to the nozzle as heretofore is capable of being adjusted with regard thereto,
this adjustment being conveniently effected through the medium of screws attached
to the upper end of the sleeve and connected by nuts to brackets on the nozzle or to
the flanged joint by which the nozzle is connected to the suction pipe. Any other
equivalent means of adjustment may be employed, the sleeve being in any case
maintained concentric with the nozzle by distance pins or brackets in the annular
space between them.
My second improvement relates to the cap which is applied to the mouth of the
inlet nozzle when it is brought into proximity to mats used to separate different
kinds or consignments of grain, and the improvement consists in the substitution for
the cage described in my former Specifications of a cap formed of a solid disc
connected by legs to a short tube fitting in the end of the nozzle with regard to
which the cap plate occupies the same relative position as the cage before described.
The object of using a solid cap as above described is to prevent the mats being
influenced by the air current and impeding the freedom of motion of the nozzle by
clinging thereto..
My third improvement relates to the provision of an extra nozzle with air sleeve
for attachment to the main nozzle when the matters are to be removed from between
decks or in situations where there is insufficient head room for using the main nozzle
in ordinary pendent position. This extra nozzle is similar in operation to the main
nozzle but differs in construction inasmuch as the inner tube instead of being straight
and passing concentrically through the whole length of the sleeve is bent so as to
pass out through the side of the sleeve and fits into the mouth of the main nozzle so
that the latter, which then acts merely as part of the conveying tube may assume a

page_text: more or less horizontal position whilst the sleeve of the extra nozzle is vertical, it's
lower end and that of the inner tube being plunged into the grain, etc.; and acting as
before described in respect of the main nozzle.
My fourth improvement relates to the oscillating twin receiver whose chambers
are alternately filled with grain, etc., from a conical hopper into which it is delivered
by the conveying pipe. It has been found in practice that when the empty
compartment is brought by the oscillation of the receiver into loading position, the
áir under atmospheric conditions with which said compartment is then filled must
first expand into the hopper which is then under partial vacuum, the air in forcing
itself through the discharge port of the hopper disturbing the grain there collected
and for the time being preventing its exit. In order to avoid this interruption and
interference with the proper action of the apparatus, I provide means whereby just
before the empty compartment assumes the position for loading, its atmosphere is
placed under the same conditions as regards pressure as that of the hopper above.
For this purpose I provide exhaust chambers which are in connection by pipes with
the upper part of the hopper, or with the suction pipe or otherwise, so that they are
always under the same air conditions as the hopper. These chambers communicate
with ports opening through the valve seat and the valve face on the oscillating twin
receiver works past these ports, the operation being such that when the full com-
partment is being discharged and its inlet port is necessarily open to the atmosphere
the port of the corresponding exhaust chamber is closed by the valve face of the
-oscillating receiver, but when the other compartment is partly loaded the empty
compartment is put into communication with the corresponding exhaust chamber
and its atmosphere exhausted to the same extent as that in the hopper. To effect
this, the twin receiver is so mounted and the counterweighted latch mechanism by
which it is controlled is so arranged that the oscillation of the receiver in each
direction is divided into two stages, the first and shortest movement being performed
freely by the weight of a partial load in the compartment being filled, overcoming
the previous preponderance of the other compartment whereupon the latch
mechanism comes into action and delays the completion of the oscillation until the
loading compartment is fully charged whereupon the load overcomes the latch
mechanism and the fully-loaded compartment is discharged as described in my said
previous Patents. It is when the empty compartment is in intermediate position
that it is put in communication with the corresponding exhaust chamber in order
that it may be partly exhausted in readiness to be charged with grain, etc. Instead
of using two such exhaust chambers, one may serve for both compartments of the
receiver which would be alternately put in communication therewith by suitably-
arranged ports, the operation being the same as above described, and such ports
may either be in the valve governing the flow of grain to the one or other compart-
ment, or a special valve might be used in which case the exhaust chambers may be
mounted upon or beneath the oscillating receiver instead of being above it.
In order to permit the valve to work over its seat with so little friction as to admit
of the receiver being easily oscillated by light grain and yet prevent leakage of air
between the valve and its seat, covering strips of thin metal are provided which are
attached to the one part, overlap the joint, and are pressed against the other part,
so as to prevent the influx of the air.
My next improvement consists in improved means for enabling the current of
air after doing its duty as a conveyor for the grain, to disentangle itself more
readily therefrom so as to carry off less of the solid particles along with it than
heretofore, this part of the invention being applicable to the apparatus forming
the subject of my former Patent No. 6665 dated the 17th day of April 1891 for
separating "stive" or dust from air laden therewith (otherwise than in the
pneumatic conveyance of grain, etc.,) for instance in flour mills. According to this
improvement, the conveying pipe terminates in a downwardly-directed end
surrounded at a distance by a converging cone contained within or formed by the
hopper above referred to, or other casing, the pipe extending downwards through

page_text: the cone from the larger towards the smaller end and its mouth being situated
co-axially within and at a short distance above its lower and smaller end so that
between the pipe and the adjacent sides of the cone an annular space is left at
which the air can escape from the stream of solid particles which by virtue of
their own momentum are projected through the orifice of the cone and received in
the chamber below. The sectional area of the annular space between the pipe
and the cone is just sufficient at the part immediately surrounding the lower end of
the pipe, to permit the escape of the air with a velocity rather less than that at
which it emerges from the conveying pipe but the sectional area of said space
gradually increases in the upward direction until it equals that of the hopper
itself, so that the velocity of the air gradually diminishes as it ascends through
the hopper which is continued upwards of the full diameter to such a height as to
permit of most of the light particles that may have been carried along with the
air, settling down and being caught by the sides of the cone down which (being
there protected from the full force of the current) they will creep until they pass
through the lower end of the cone into the receiver below. The cone may either
be pendent within the hopper or it may be continued downwards in the form of a
reverse or diverging cone connected by its smaller end to the smaller end of the
first mentioned cone and at its larger end with the chamber leading to the valve
port. The suction pipe connected to the upper end of the hopper or casing is
itself led (in the same way as the grain conveying pipe) into a second and similar
separator by which the remaining traces of dust are removed from the air and
received in a closed stationary hopper-shaped chamber provided with a valve to
sbut off communication with the separator whilst the chamber is being emptied, a
discharge door at bottom closed by external air pressure, an air inlet controlled by
a stop-cock at top, and a bye-pass air pipe also controlled by a stop-cock and
connecting the top of the chamber with the separator above so that the chamber
may be put under the same conditions of vacuum as the separator before the
valve therein is operated. The same construction of the separator and receiver
would be adopted in applying the dust separator to the purpose of separating the
"stive" or dust from the air which has been used to ventilate mills for grinding
corn, or in lieu thereof I may employ for the purpose of drawing off the dust
from the separator the same arrangement of oscillating twin receiver as previously
described.
Dated this 22nd day of February 1802
F. E. DUCKHAM,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in Apparatus for the Pneumatic Conveyance of Grain
and other Matters, and for Separating Dust from Air laden
therewith.
I, FREDERIC ELIOT DUCKHAM, of Millwall Docks, London, E. Civil 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 further improvements in pneumatic apparatus for loading,
unloading, or transferring grain or other granular or pulverulent matters in bulk
(such as seeds, sand, small coal, and gravel, for example) for which former Letters
Patent were granted to me respectively dated the 29th day of July 1890, No. 11884
and the 24th day of February 1891 No. 3376, and to improvements in the apparatus

page_text: 1
.
for separating dust from air forming the subject of Letters Patent dated the
17th day of April 1891, No. 6665.
My present improvements relate, first, to the nozzle at which the grain, etc.,
enters the conveying pipe; secondly, to the apparatus into which the grain is
delivered by the conveying current; thirdly, to the apparatus by which the airat
after doing its duty as a conveyor for the grain, etc., is separated from the grain
and accompanying dust, this part of the invention being also applicable in the
separation of dust from air in flour mills and the like.
The invention is illustrated in the accompanying drawings, forming part of this
Specification, wherein
Figure 1 is a vertical section of the suction nozzle provided with means of
adjustment as hereafter referred to.
Figure 2 is a sectional elevation of the extra attachment nozzle for use in
certain cases.
Figure 3 represents at the upper part a vertical section of the hopper in which
the separation of the air from the grain, or dust of any kind with which it may
be laden, is effected and at the lower part a part sectional elevation of the
oscillating air-lock delivery box by which the grain or other matters after being
BO separated is received and delivered.
Figure 4 is a similar view shewing the delivery box in the position it assumes
during the operation of filling.
Figure 5 is a transverse vertical section on the line 6-6 Figure 4.
ion of another dust separating apparatus by
ausare separated from the air, this form of the apparatus
being particularly applicable where the quantity of dust present in the air is com-
paratively small not only in the pneumatic couveyance of grain but in other
industrial operations as for example in the separation of dust from air in flour
mills or in other places where the air is laden with dust of an injurious character.
The same letters of reference indicate the same parts in all the figures.
11
. Referring to Figure 1, the improvement in the nozzle, which is immersed in the
mass of the grain, etc., to be conveyed, has for its object to enable the proper
proportion of the conveying current of air relatively to the grain or other material
conveyed by it, to be maintained under the varying conditions of working and for
this purpose the lower end of the sleeve B (through which the air necessary for
the pneumatic conveyance of the grain, etc., is admitted to the nozzle A) is made
adjustable in height with regard to the lower end a of the said nozzle. The proper
relative position of the lower end b of the sleeve with regard to the mouth a of
the nozzle is dependent on the amount of vacuum employed, on the height or
distance to which the material is to be conveyed, and on the angle of repose of the
said material, which varies with the nature of the material and in the case of grain
with the particular kind and condition of the grain. This adjustment of the air-
supplying sleeve B relatively to the mouth a of the nozzle A is effected by fitting
the sleeve B to be slid on the nozzle preferably through the medium of screw-
rods attached to the upper end of the sleeve B and connected by nuts to brackets
on the nozzle A or to the flanged joint a¹ by which the nozzle is connected to the
conveying pipe. Any other equivalent means of adjustment may be employed,
the sleeve being in any case maintained concentric with the nozzle A by distance
pins or brackets in the annular space between them, the said brackets being
fixed to the sleeve and sliding on the nozzle, or vice versa. It will be obvious that,
instead of the whole sleeve being adjustable, the lower part might be a short
adjustable length fitted to slide telescopically upon the remainder of the sleeve, as
in Figure 2 for instance.
Figure 2 represents a bent nozzle A to be substituted for the nozzle A when the
grain, etc., is to be removed from between decks, or other situations where there is
insufficient head room for using the straight nozzle A in the pendent position. In
this case the inner tube A¹ is bent so as to pass out through the side of the sleeve B¹
:

page_text: and the lower end B' of the sleeve is made to slide telescopically on the main part
of the sleeve and is adjusted by screws and nuts, as before described. In either
case the upper end of the sleeve may be open or the admission of air may be
controlled by an apertured regulator R.
Figures 3, 4, 5, represent the oscillating two-chambered air-lock delivery box:
whose chambers D D¹ are alternately filled with grain, etc., from a conical hopper E.
in which the grain, etc., is deposited by the conveying current, and with which the
chambers DD' communicate alternately through a valve H under the control of
counterweighted latch mechanism. When the compartment D or D' dischargesia.
load it is filled with air under atmospheric conditions which must expand into the
exhausted hopper E before any grain, etc., can enter the said compartment. In
order to avoid the interruption and interference with the proper action of the
apparatus which would be caused by the air passing through the grain in the
hopper E, I provide means whereby equilibrium of air pressure is established
between the empty compartment D or D₁ and the hopper E just before the said.
compartment assumes the position for loading. For this purpose, I provide bye--
pass chambers 'G G' and pipes g g' in constant communication with the upper part.
of the hopper E, the chambers G G having ports 92 93 which open through the
seat of the valve H. When the one compartment (D' in Figure 3 for instance) is
being discharged and its inlet port ¹ is necessarily open to the atmosphere, the
port g of the corresponding bye pass G¹ is closed by part of the valve face H;-as
shewn in Figure 3. When, however, the other compartment is partly loaded, the
empty compartment is put into communication with the corresponding bye-pass...
and equilibrium of pressure is established between the empty compartment and the
hopper E. With this object the oscillation of the air-lock delivery box D D¹ in
each direction is divided into two stages. For instance, Figure 3 shews in full and
dotted lines respectively the two extreme positions and supposing the compartment D
is being filled as shewn by the full lines, Figure 4 shews the intermediate position
assumed after the said compartment has been loaded to a certain extent in which
position the delivery box is detained until the compartment D is fully loaded
whereupon the oscillation is completed to the position shewn in dotted lines. The-
first and shortest of these movements is performed freely, the counterweighted
lever I being prevented by a stop from raising latch i high enough to catch the
stud until the position shewn in Figure 4 is reached. When the compartment D-
is fully charged, the counterweight I is overcome, oscillation is completed, and the
radius link causes the latch i to be drawn out of engagement with the stud ..
On reaching the extreme position the loaded compartment is discharged by 'the-
port opening to the air and door d falling open. Instead of using two bye-
passes G Gone may serve for both compartiments DD' which would be alternately-
put in communication therewith as above described.
In order that the valve H may work with little friction and yet prevent influx of
air between the valve H and its seat, covering strips of thin metal jj are attached,.
say, to the valve seat so as to cover the joint, as shewn in Figure 5.
The upper part of Figure 3 illustrates improved means for enabling the current.
of air after doing its duty as a conveyor to disengage itself more readily from
the grain or other matters conveyed. The downwardly-directed nozzle of the
conveying pipe K is surrounded at a distance by a converging cone L contained.
within or formed by the lower part of the hopper E or other casing, the mouth k
of said pipe being situated co-axially within and at a short distance above the lower
and smaller end of the cone I so that between the pipe and the adjacent sides of
the cone there is an annular space at which the air (indicated by the full line
arrows) can escape from the stream of solid particles (indicated by the dotted
arrow) which by virtue, of their own momentum are projected through the orifice
of the cone and are received in the lower part. of the hopper E whence they pass
into the closed chamber below. The sectional area of the annular space between
the pipe K and the cone L' is just sufficient to permit the escape of the air with a.

page_text: velocity rather less than that at which it emerges from the conveying pipe K and
as the sectional area gradually increases in the upward direction the velocity of
the air gradually diminishes as it ascends through the hopper E. The diminished
velocity of the air and the height to which the hopper is carried permit most of
the light particles (carried along with the air) to settle down and be caught by the
sides of the cone L down which (being there protected from the full force of the
current) they will creep until they pass through the lower end of the cone into the
space below. The cone L may either be pendent within the hopper, as shewn, or it
be continued downwards in the form of a reverse or diverging cone, as indicated by
dotted lines L', connected by its smaller end to the smaller end of the cone L and
at its larger end with the chamber leading to the port in the valve seat.
may.
The exhaust pipe M is connected to the upper end of the casing E and led into
a second similar separator, represented in Figure 6 by which the remaining traces
of dust are removed from the air. This separator N has a cone n into which the
end m of the pipe M is led, as before described in respect of pipe K and cone L,
the exhaust pipe O going to the fan or other exhausting engine. The lower end
of the separator N communicates with a closed chamber P in which dust separated
from the air is received. As the weight of the dust may be insufficient to operate
an oscillating air-lock delivery box, such as above referred to, the chamber P may
be stationary and a hand-valve p be provided to shut off the communication whilst
the chamber P is being emptied through the discharge door p'. A bye-pass air
pipe Q controlled by a three-way cock serves to connect the upper part of the
chamber P with the hopper N at a point above the cone n so as to establish
equilibrium of pressure before the valve p is opened. The door p' is held closed
by the external atmospheric pressure whilst the chamber P is being filled and the
three-way cock g serves also to admit air to the chamber P, in order to allow the
door pl to be opened to discharge the dust collected.
In applying the dust-separator above described for separating dust from air
which has become laden therewith in industrial operations, the dust-laden
atmosphere would be exhausted through the separator as in the conveyance of
grain and if the quantity or weight of the dust separated from the air is sufficient
to operate an oscillating receiver such as shewn in Figure 3 I may use that instead
of the stationary receiver P.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, declare that what I
claim is
1. In apparatus for the pneumatic conveyance of grain and other matters,
making the air-supply sleeve or the lower end thereof adjustable with regard to
the nozzle, substantially as and for the purpose specified.
2. The combination, with the sleeve or the lower end thereof made adjustable
with regard to the nozzle, of screw-rods and nuts for effecting the said adjustment,
as specified.
3. The inlet nozzle with a surrounding air sleeve adjustable at it lower end, the
inner tube being bent so as to pass through the side of the sleeve, substantially as
specified.
4. The improved apparatus for separating solid particles from air laden therewith,
consisting of a downwardly-directed discharge nozzle surrounded at a distance by
a conveying cone, the nozzle terminating within and just above the lower and
smaller end of the cone, the nozzle and cone being contained within an exhausted
hopper leading to a closed receiver below and in connection at top with an
exbausting engine, substantially as specified.
5. In pneumatic conveying apparatus the combination, with the exhausted hopper
and with the two-chambered air-lock delivery box oscillating under the control of
counterweighted latch mechanism, of bye-pass passages in permanent. communication
with the upper part of the hopper and with ports controlled by the valve which

page_text: determines the flow of the particles to the one or other chamber of the delivery
box whereby equilibrium of pressure is automatically established between the
empty chamber and the hopper before the said chamber arrives at the loading
position, as specified.
Dated this 22nd day of November 1893.
F. E. DUCKHAM,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.