Improvements in or connected with Apparatus for Drying Tea, Coffee, and other Substances, and in Furnaces or Heat-generating Apparatus for use in connection therewith.
Year: 1893

page_text: Date of Application, 15th May, 1893
Complete Specification Left, 14th Feb., 1894-Accepted, 12th May,
1894
PROVISIONAL SPECIFICATION.
Improvements in or connected with Apparatus for Drying Tea,
Coffee, and other Substances, and in Furnaces or Heat-generating
Apparatus for use in connection therewith.
I, WILLIAM ALFRED GIBBS, of Gilwell Park, Chingford, in the County of
Essex, Gentleman, do hereby declare the nature of this invention to be as
follows:-
My invention partly relates to drying apparatus of the kind described in the
Specification of former Letters Patent granted to me No. 8796 of 1889, that is to
say, a drying apparatus having an inclined rotating cylinder provided internally
with shelves for raising the material to be dried and allowing it to drop on to
an air duct within the cylinder through which the air for drying the material is
passed.
According to this part of my invention the shelves herein before referred to
are made deeper, and provided with lips or flanges at the edges so that the said
shelves will lift more material than hitherto and allow it to drop more slowly
than is the case when plain shelves are employed. In some cases I make the
shelves with duplicate lips which tend to retard the fall of the material off the
shelves or I fix to the said shelves what 1 term "intercepting boards" against
which the material falling from the shelves strikes whereby it is more or less
distributed.
The air-duct is arranged to project beyond the drying cylinder at one end and
provided with a door for removing therefrom any dust which may accumulate.
The said air-duct, for a short portion of its length contained within the cylinder,
is unperforated, whilst the other portions are perforated with holes which vary in
size, the largest holes being adjacent to the unperforated portion of the air-duct
(which is at the end at which the materials to be dried enter the cylinder) and
gradually decreasing in size towards the other end.
In using the apparatus for drying materials such as tea, I advantageously
provide in the walls of the drying cylinder near the discharge end, panels of
wire-netting or other suitable material through which the smaller or broken
portions of the dried leaves will fall and be thereby separated from the other
parts being dried; doors or shutters being provided for covering such panels
when required.
When the apparatus is to be used for materials, such as coffee, which require
to be retained in the cylinder for a considerable length of time, I provide in the
air-duct a spiral conveyor which, as the materials being dried gravitate towards
the lower end of the cylinder, will return them to the upper end.
When the apparatus is to be used for drying hay, corn in the straw, tares,
irrigation grasses, clover or other fibrous substances, tines instead of shelves may
be used for lifting and distributing the material, which tines serve to carry
shelves, when the apparatus is afterwards to be used for drying wheat or granular
materials.
The apparatus which is intended for drying hay is by preference made of a
diameter of, say, from eight to twelve feet, and the air-duct is dispensed with,
the hot air for drying the materials passing directly through the cylinder from
the feed end thereof. Air-ducts of any desired section can be adjusted when the
cylinder is used (after harvest) for drying wheat or other grain.

page_text: When the apparatus is to be used for drying cocoa and other substances which
would be injured by the direct action thereon of the products of combustion from a
furnace, I construct a cylinder or drum of hexagonal or octagonal form provided
with a series of longitudinal and segmental chambers separated by spaces, through
which hot air or steam flows, to heat the sides of the said chambers, the said
cylinder or drum being also enclosed by a jacket so that the peripheral surfaces of
the said chambers shall be heated by the waste heat after it has passed between
the said chambers.
The furnaces for generating heat for use with the drying apparatus hereinbefore
described is constructed as follows:-
:-
Upon two walls is carried a chamber communicating with a fan for drawing the
air through the said chamber and delivering it to the drying apparatus. The
bottom of the said chamber is formed of netting or of perforated material which
divides this upper chamber from the lower one formed by the walls and parallel
with the outer sides of the said walls are built other walls so as to form two
troughs; the upper brickwork courses of which are inclined inwards at the top so
as to narrow the openings. In this apparatus the draught produced by the fan
causes the air to enter through the open troughs and to pass down through the fuel
and through arches, holes or passages in the inner walls of the troughs into the
space beneath the perforated bottom of the said air chamber, and thence through
the said perforated bottom into the said upper air-chamber and through the fan
whence it is delivered to the point at which it is to be used. On the ground space
enclosed by the two inner walls of the furnace I carry up a bank of fire-brick so
that as the flames and products of combustion are drawn through the holes or
passages they impinge on this bank which soon becomes red-hot so as in a great
measure to consume any smoke. I sometimes fill the whole chamber with chalk
for the still better consumption of smoke and for arresting sulphur fumes.
In order to prevent the waste of heat by radiation from the surfaces of the said
upper air-chamber, the said surfaces are jacketted and the jacket-space connected
with the fan so that a current of air will be drawn through the jacket space.
the said air chamber is constructed of brick, this jacket is not needed.
If
Instead of using the drying cylinders as hereinbefore described or in conjunction
with the said cylinders, I sometimes erect two vertical chambers, the adjacent
faces of which are provided with louvres, the louvres on one face alternating those
on the other face in such a manner that grain introduced between the said chambers
will fall from one louvre to the other in a zig-zag direction between the louvres.
Holes or perforations are formed beneath the louvres through which the hot air can
be driven or drawn through the material being dried. I prefer to drive this hot air
into one of these two chambers by a fan from a furnace or by a fan blowing over
heated pipes in the said chamber; and to draw the moistened air off from the other
chamber by a suction fan steam jet or chimney draft. Any of the well known
feed-hoppers and delivery regulators can be adjusted to the space between these
chambers for the supply and discharge of the wheat or the like. The apparatus
thus described can be usefully applied as a preliminary dryer from which the grain
can be passed into any of my present rotating dryers.
Dated this 15th day of May 1893.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant..

page_text: COMPLETE SPECIFICATION.
Improvements in or connected with Apparatus for Drying Tea,
Coffee, and other Substances, and in Furnaces or Heat-generating
Apparatus for use in connection therewith.
I, WILLIAM ALFRED GIBBS, of Gilwell Park, Chingford, in the County of
Essex, Gentleman, 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 apparatus for drying fibrous materials, tea, coffee, grain
and other substances and it comprises the improvements hereinafter described.
The accompanying drawings illustrate apparatus constructed according to my
invention, in the several figures of which similar reference letters indicate
corresponding parts.
For drying hay, wheat in the straw, flax and other fibrous products I construct
and actuate cylinders in the same manner as those of my well-known corn and tea
drying cylinders described in the Specification of Letters Patent No. 2464 of 1886,
but of diameters sufficiently large (say eight to twelve feet) to allow the fibrous
products to be lifted up by tines fixed within the cylinders, the said products falling
again as the cylinders rotate, without being entangled or twisted by the rotation.
Figures 1 and 2 represent respectively an end view and a longitudinal section
of one of these cylinders, a, a indicating the tines.
In the said cylinders I prefer to dispense with the central air-ducts and to send
in the hot air from my fans and furnaces at the feed end, instead of the discharge
end, as indicated by the arrows in Figure 2. I also prefer to contract the diameter
at the feed end to, about, half that of the main cylinder also as shewn in Figure 2
for two reasons, videlicet :-
1stly. To reduce the cost of the driving gear-wheel carried thereby.
2ndly. To allow the fibre at each rotation to fall out of range of the column of
hot air so as to avoid the risk of scorching.
In order to render my dryers easily portable I sometimes mount them on trollies
and for lessening cost of freight for export I construct them in panels or sections
which can be easily taken apart and fitted together. I advantageously shape the
internal tines a, a hereinbefore referred to as tenter-hooks and vary the lengths of
these tines to suit different lengths of fibres to be dried.
Where grain or seed as well as fibres have to be dried I adjust shelves either.
upon or between the tines at such curves or angles as to lift up and pour out
such seeds or the like so that they fall in showers through the central column of the
hot air. This arrangement is illustrated in Figure 3 which is a similar view to
Figure 1, b, b indicating the shelves. Where such seeds or the like require to be
subjected to the action of warmed air at moderate temperatures for several hours,
as, for example, pease, beans, and coffee berries which are not dried in combination
with fibre, I deepen and curve these shelves or make them trough-shaped so as to
lift up and pour out very large quantities of these seeds or berries and I dispense
with the tines and revert to one of my well-known forms of air-ducts preferably
that having the A section as described in the Specification of my former Patent
No. 8796 of 1889. This arrangement is illustrated in Figures 4 and 5 which
represent respectively a transverse section and a longitudinal section of the same,
c indicating the air-duct. I also adjust intercepting or baffle-plates d, d (or curved
troughs) in the cylinder so that as the seeds or berries are poured off the shelves b, b
they are received on these plates and again poured out over the apex of the air-
duct c.
I also provide, preferably in the lower part of the air-duct, a conveyor e
to carry back the seeds or berries to the higher end of the cylinder and thus create
a continuous circulation of the said seeds or berries for so long a time as may be

page_text: found needful to subject them to the action of the warmed air, openings e¹ and
being provided in the air-duct for the ingress and egress respectively of the seeds
or berries. I construct the two ends of the cylinder and sometimes the cylinder
itself of wire-net, so as to allow free exit of the steam.
For discharging the seeds or berries when dried, I provide sliding doors ff at
one end so that, by opening the said doors and then elevating the cylinder at the
other end and continuing the rotation, the said seeds or berries are emptied out.
The other end is provided with a suitable feed-hopper g.
I sometimes prefer to feed the seeds or berries into the hopper g from a vertical
dryer shewn in Figures 6 and 7 which represent respectively a vertical section and
a horizontal section of the same, it being constructed in the form of a hollow square
having a central chamber with sides perforated with lines of holes, over which
holes I adjust louvres i, i which admit the outward passage of hot air from the
centre, but prevent the passage inward of the seeds, berries or the like.
I adjust an outer casej parallel to these louvred sides and at a distance of from
3 to 6 inches therefrom. This outer case is provided with holes and louvres i, i¹
similarly to the inner case / but so adjusted that the seeds or berries slide down in
a zig-zag manner from the louvres on the inner case h to the louvres on the outer
case j and thus pass down from the top to the bottom of the vertical apparatus.
Warmed air being delivered into the central chamber h of the inner case of this
apparatus passes through the holes and under the louvres i, i of the said inner case
and thence through the seeds or berries, finally passing out through the holes of
the outer case j. Where the percentage of water to be dried off is small (as in
wheat from the whizzer) this vertical dryer is used alone as indicated in the
drawings as it can be extended in size and length so as to deal with a large bulk of
wheat.
When drying materials such as starch, flour, sugar or the like upon which hot
air direct from a furnace would act detrimentally, I construct a casing of hexagonal
(or other polygonal) shape as shewn in Figures 8 and 9 which represent respec-
tively a longitudinal section and a transverse section on the line 9-9, Figure 8, of
the same, the said casing having a series of longitudinal compartments k, k and a
central air-duct or passage c and I drive hot air into this duct so as to heat the
walls of the compartments, which walls are hollow and so impart transmitted
heat only to the product. The product being fed into these compartments is, owing
to the rotation of the casing or drum and the angle at which it is set, carried down
from the upper to the lower end and there discharged.
I adjust an outer jacket m over this hexagonal casing or drum and permit the hot
air after it has passed up the centre air-duct c to emerge at the fan-end (the
walls, at this point communicating with the jacket m) and pass out between
the said jacket and the outer surface of the drum so as to give external heat to
the said drum.
When starch or other like products to be treated are in the semi-fluid condition
I adjust to the feed-end of this hexagonal drum a short length of a plain cylinder n,
as shewn in Figures 10 and 11 which represent respectively a longitudinal section
of this arrangement and a transverse section on the line 11-11, Figure 10, the said
cylinder being provided with a scraper o and crushers p, p (like miniature clod-
crushers) and a portion of the air from the air-duct ĉ being delivered through a
casing conto the semi-fluid material.
The furnace for generating heat for use with the drying apparatus hereinbefore
described is illustrated in Figures 12, 13 and 14 which represent respectively a
longitudinal section, a transverse section and a plan with the upper part removed and
is constructed as follows :-
Upon two walls 9, 9 is carried a chamber r communicating with a fan s for
drawing the air through the said chamber and delivering it to the drying apparatus.
The bottom t of the said chamber is formed of wire-netting or of perforated
material which divides this upper chamber from the lower one u formed by the
walls 9, 9 and parallel with the outer sides of the said walls are built other walls e, v

page_text: so as to form two troughs w, w, the upper brickwork courses of which are inclined
inwards at the top so as to narrow the openings. In this apparatus the draught
produced by the fans causes the air to enter through the open troughs w, w and to
pass down through the fuel contained therein and through arches, holes or
passages x, x in the inner walls of the said troughs into the space u beneath the
perforated bottom t of the said air-chamber and thence through the said.
perforated bottom into the said upper air-chamber and through the fans whence it.
is delivered to the point at which it is to be used. On the ground space enclosed
by the two inner walls q, q of the furnace I carry up a bank y of fire-brick so that
as the flames and products of combustion are drawn through the holes or
passages, they impinge on this bank which soon becomes red-hot so as in a great
measure to consume any smoke. I sometimes fill the whole chamber u with chalk.
for the still better consumption of smoke and for arresting sulphur fumes. In some
cases an additional opening a' is provided for admitting air to the chamber u.
In order to prevent the waste of heat by radiation from the surfaces of the said
upper-air-chamber r, the said surfaces are jacketted and the jacket-space z connected
with the fans so that a current of air will be drawn through the said jacket
space. If the said air-chamber is constructed of brick, this jacket is not needed.
Or instead of the hereinbefore described furnace I may use the smokeless.
furnace described in the Specification of my Patent No. 5980 of 1888 or any other
suitable form of furnace.
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 an apparatus for drying hay and other fibrous materials, the combination
with a rotating cylinder of relatively large diameter of tines or hooks arranged.
within the said cylinder, substantially as described.
2. In drying apparatus having a cylinder provided with internal hooks or tines
as described in the preceding claiming clause, arranging at the feed end a cylinder
of smaller diameter than the drying cylinder, the said smaller cylinder which
serves as the feed-hopper also serving for the introduction of the hot air and
for carrying a gear-wheel by means of which the drum is rotated, substantially as.
described.
3. In a drying apparatus having internal hooks or tines as referred to in the
first claiming clause, the combination with the said tines of shelves for lifting.
grain or seed, substantially as described.
4. In an apparatus for drying grain or seed the combination with a rotating
cylinder provided with trough-shaped shelves and an air-duct, of a conveyor
arranged in the lower part of the cylinder and advantageously within the said
air-duct, the said conveyor serving to return the partially dried materials from the
lower to the upper end of the drying cylinder, substantially as, and for the purpose,.
described.
5. In an apparatus for drying grain, seeds and the like in which two sets of
louvres are opposed to one another in such a manner that the grain passing between
the said louvres will flow in a zig-zag direction, forming one set of louvres on the
outer walls of a rectangular chamber and the other set on the inner walls of a.
similarly shaped but larger chamber or casing, holes being formed beneath the
different louvres so that hot air introduced into the central chamber will escape
therefrom through one set of holes, thence pass through the grain or material flowing
between the louvres and then escape through the holes beneath the louvres on the
outer casing, substantially as described.
6. A drying apparatus wherein a drum of polygonal shape in transverse section.
is employed, the said drum having within it a series of longitudinal compartments
for containing the substance to be dried and an air-duct or passage so arranged that
as hot air is passed through the said passage it will heat the inner walls of the
longitudinal compartments, a casing being arranged over the drum and receiving the

page_text: hot air discharged from the central air-passage so as to cause the heating of the outer
walls of the compartments, substantially as described.
7. The combination with the drying apparatus referred to in the preceding
claiming clause of a cylindrical extension provided with scrapers and crushers,
substantially as described.
8. The combination with drying apparatus of a furnace comprising two fire
troughs and a central chamber common to both of such troughs and communicating
with a fan in such a manner that when the fan is in operation the products of
combustion are drawn from the troughs into the central chamber and thence delivered
into the drying apparatus, substantially as described.
Dated this 14th day of February 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.