Improvements in Centrifugal Machines for Expelling Water from Coffee Beans and analogous Granular Materials.
Year: 1896

page_text: Date of Application, 7th Apr., 1896-Accepted, 9th May, 1896
COMPLETE SPECIFICATION.
Improvements in Centrifugal Machines for Expelling Water from
Coffee Beans and analogous Granular Materials.
1, MANUEL SILVESTRE AYAU, residing at No. 6 South Ninth Avenue, in
Guatamala City, in the Republic of Guatamala, in Central America, 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 :-
The invention may be used to treat other loose material, but it is intended more
especially for expelling the surplus water from freshly washed coffee, and I will
describe it as thus applied. The drying of coffee by this machine is preparatory to
the treatment with warm air in drying, which latter operation, it will be understood,
is effected in a separate machine. The coffee beans come from the washing in a
very wet state. I whirl them rapidly in a perforated drum and drive out all the
water which can be detached by centrifugal force. I provide means for moving
the coffee grains gradually lengthwise of the perforated drum, and means for
feeding in the coffee beans with any quantity of water with which they may be
encumbered, continuously at one end of the drum, driving off the water by the
intense centrifugal force during their slow passage longitudinally of the drum, and
allowing the beans to escape from the other end.
I effect the movement of the coffee beans longitudinally along the interior of the
rapidly revolving drum by means of a screw wing or spiral blade carried on a shaft
which is revolved at a high rate nearly coinciding with that of the drum. The
difference in the rotation of the screw and the drum causes the screw to act on the
several coffee grains, moving them gradually and continuously along in the interior
of the drum, notwithstanding the energy with which they are held outward by the
strong centrifugal force.
I can feed the coffee into the machine at a variable rate according as its
condition or other circumstances shall require. I attain this by making the
feeding motion independent of the other motions, so that the feeding can be
hastened or retarded independently.
The accompanying drawing forms a part of this Specification and represents
what I consider the best means of carrying out the invention.
It is a central longitudinal section.
Referring to the letters of reference marked thereon, A is a rigid frame-work of
cast iron or other suitable material, adapted to support the several parts, and A' is
a hopper at one end, in which the coffee may be deposited either continuously or by
rapidly succeeding installments.
B is a drum baving small perforations along its length, and equipped with
trunnions B1, B2, by which it is supported in the framing A. It receives rapid
rotatory motion through a pulley B 3, which receives a belt not represented, driven
by a steam engine or other suitable power. One end receives the coffee through
a fixed tube A 2, which extends in a sufficient opening in the interior of the
trunnion B 2. This tube receives the coffee freely at the outer end, and delivers it
into the interior of the rapidly revolving drum at the inner end. The feeding-in is
effected and controlled by a helical wing or screw-thread C¹ formed on a shaft C,
which is mounted in the center of the tube A 2, and is turned at a proper rate by
means of a pulley C2 on the overhung outer end, which receives a belt not
represented.

page_text: D is a shaft extending longitudinally in the axial line of the drum B, and
rotated at a nearly but not exactly corresponding rate by means of a pulley D2
receiving a belt not represented. A continuous spiral blade D' having a diameter
only a little less than the interior of the perforated drum B, is supported and
revolved in such interior by being secured to arms fixed on the shaft D. The
spiral may be right-handed or left-handed. The difference in the rate of rotation
between the drum B and the spiral blade D¹, must be in the proper direction to
urge the contents of the drum towards the delivery end, the left-hand.
The shaft D is supported at one end by a fixed bearing A 3, which is outside of
or beyond the pulley B 3. The other end of the shaft D is a little within the
opposite end of the drum. It is held in a bearing B4 which is fixed to and
revolves with the drum in its interior. The bearing is carried by oblique arms B 5
arranged to allow the coffee to fall through the spaces between and accumulate as
a concentric layer in the interior of the drum. The disposition of the coffee to
adhere by centrifugal force to the interior of the drum, is overcome by the action
of the spiral blade D', which acts screw-wise to urge it constantly forward from the
receiving end towards the delivery end, thus allowing the material to be received
continuously and to be delivered continuously, treating a large quantity of coffee
thoroughly and effectively in a short time.
A lip A 5 may extend around in the interior of the casing A 4 in the position
indicated, to secure a more complete separation of the coffee from the water, as
both are delivered tangentially, within the casing.
A large proportion of the water will be driven out immediately on the material
being received and caused to rotate with the drum; I provide a scraper D 5 at that
end of the spiral blade which insures that the material shall be agitated and started
on its journey longitudinally of the machine. The successive spirals of the blade
continue the movement of the coffee, and on its reaching the delivery end of the
machine it is discharged through the apertures d.
The casing A 4 is of sheet metal or other suitable material adapted to receive
the drops of water which are discharged tangentially from the perforated body of
the drum and to allow such water to trickle down. It is discharged at the bottom
through a spout A 6. The several coffee beans as they are expelled from the
delivery end of the casing, may also fly out tangentially and being arrested by a
corresponding portion of the enclosing casing, lose their rotatory velocity and drop
down and are discharged through an inclined spout A 7, to be subsequently treated
by a Ribon drying machine or in any other desired manner to complete the
drying.
The bearing for the inner end of the feed shaft C is formed by boring a hole of
the proper size in the end of the shaft D, as shown by dotted lines.
The construction provides a liberal space between the oblique arms B for the
reception of the coffee into the interior of the drum, and causes it to move outward
immediately, so as to strike the inner surface of the drum at the entering end and
to be treated by the centrifugal force in traversing the whole length of the
interior.
The tube A2 extends quite through the bearing and prevents the coffee from
being rotated until it has passed completely within the drum. The screw thread C¹
on the shaft C may be extended still farther inward if desired.
Modifications may be made without departing from the principle or sacrificing
the advantages of the invention. I have shown the drum ends as cast iron and the
cylindrical portion as boiler iron perforated. I have shown the bearings for the
trunnions as babbited; but all these details may be varied.
I have shown the casing A as provided with liberal openings which allow the
circulation of air. The water discharge spout A may deliver a current of air
generated by the centrifugal force. I have shown tie-bolts outside of the drum
holding the beads very firmly at the proper distance apart. These bolts serve to
some extent as wings to promote the driving of air outward through the water
delivery spout.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a centrifugal drying machine, the horizontal perforated drum, and means
for revolving it rapidly, in combination with provisions for feeding in the material
at one end and delivering it continuously at the other end, and with a shaft in its
interior revolved relatively thereto, a spiral blade carried on such shaft for urging
the material longitudinally in such drum by such revolution, and also a scraper D5
carried by such shaft and extending horizontally beyond the end of such spiral
close to the inner surface of the drum, all arranged for joint operation substantially
as herein specified.
2. In a centrifugal drying machine, the perforated drum and means for revolving
it, in combination with the hopper A', tube A 2 and feeding screw C, C', with its
driving means C 2 for supplying the loose material to be dried, and the shaft D
with its spiral blade Di and means for turning it to urge the material longi-
tudinally in such drum, all arranged for joint operation substantially as herein
specified.
3. In a centrifugal drying machine, the perforated drum and means for revolving
it, in combination with provisions for feeding in the material at one end and
delivering it continuously at the other end, and with a shaft mounted concentrically
within the drum and revolved at a slightly different rate, a spiral blade carried on
such shaft for urging the material longitudinally in such drum, and a casing A 4
enclosing the drum and having two spouts A 6 and A 7, adapted the one to deliver
the relatively dried material through one channel and the other to deliver the
exuded water through the other channel, all arranged for joint operation substan-
tially as herein specified.
4. In a centrifugal drying machine, the perforated drum B, and means B 3 for
revolving it, and having the bearing support B4 carried by oblique arms B5
within the said drum, in combination with the shaft D with its spiral blade D' and
means D2 for turning it to urge the material longitudinally in such drum, and with
the hopper A', tube A 2, and feeding screw C, C, with its driving means C 2 for
supplying the loose material, all arranged for joint operation substantially as herein
specified.
Dated this 4th day of April 1896.
CRUIKSHANK & FAIRWEATHER,
Chartered Patent Agents,
62 St. Vincent Street, Glasgow, Agents for the Applicant.