AN IMPROVED METHOD OF AND APPARATUS FOR DRYING OR ROASTING COCOA, COFFEE, GRAIN AND SIMILAR MATERIALS
Year: 1884

page_text: COMPLETE SPECIFICATION.
I WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co, Patent
Agents, Southampton Buildings, in the County of Middlesex do hereby declare
the nature of my invention for "AN IMPROVED METHOD OF AND APPARATUS FOR
DRYING OR ROASTING COCOA, COFFEE, GRAIN AND SIMILAR MATERIALS
" and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to an improved method of drying or roasting cocoa, coffee,
grain and similar substances, and to apparatus therefor.
The said invention consists essentially in providing, particularly, in connection
with the roasting apparatus described in the specification of former Letters Patent
dated January 12th AD 1884 N° 1364, or with equivalent steam roasting apparatus,
for tempering, or reducing the temperature prevailing in the apparatus to such an
extent, and at such times, as the character of the substances to be roasted or dried
may require, the said tempering or reduction of the temperature being effected by
bringing into action some fluid or liquid, such as air, or water. The method
referred to is particularly well adapted for drying and roasting malt, rye, and other
cereals, succory and coffee, cocoa and similar fruits.
The accompanying drawing shows the apparatus for carrying into effect the
improved method.
Figure 1 is a vertical longitudinal section of the said apparatus, the latter bere
consisting of two heating drums.
Figure 2 is a vertical transverse section of the apparatus shown in Figure 1.
Figure 3 is a view of a drum showing a modified arrangement of the serpentine
pipe referred to in the said former specification and, also showing a modification in
the air-pipes used in combination with the tempering devices.
Figure 4 is a vertical transverse section of the drying and roasting apparatus in
combination with a device for tempering by means of hot water, and an air-cooling
device.
Figure 5 is a side elevation of the same.
The heating drum shown in Figures 1 and 2 consists of an outer closed steam
casing A surrounded with some suitable material to prevent the radiation of heat.

page_text: and an inner steam casing B having a longitudinal opening as shown in Figure 2.
Both steam casings, which are hollow as hereinafter described, are rigidly mounted
on the hollow shaft C so as to rotate therewith. The heating drum may be provided
with a heating serpentine pipe or coil as in Figure 3, or as described in the said
former specification, or it may be constructed with but one steam casing.
The
The shaft C is journalled in the standards D.D¹, and is rotated by means of the
belt pulley E and gear wheels F and F, or in some other suitable manner.
said shaft C is hollow and is entered by the steam inlet pipe a having the stop
valve b. A continuation of the said steam inlet pipe leaves the said hollow shaft
in a lateral direction and branches off into two arms a¹ and a³, these communicating
with the hollow spaces of the steam casings A and B respectively.
Each of the two steam casings is formed of two sheet-metal cylinders, those
of each pair forming one steam casing, being placed one within the other, or
telescoped.
The cylinders forming the casing B, are cut away for about one quarter of their
circumference in the direction of their axis, so as to cause the material roasted in
the casing or drum to be thoroughly mixed during the rotation of the drum. The
space between each two cylinders forming a steam casing, contains a number of
partitions arranged either spirally like the threads of a screw as in the casing A, or
arranged rectangularly to the axis of the casings or drums, as in the drum B. In
the latter arrangement the partitions are provided with openings so as to establish
communication between the several spaces between the rings or partitions. These
openings are made so that those of one partition alternate with, and are as far as
possible from, those of the next partition, the object of this arrangement being to
cause the steam in passing between the walls of each casing to pass over the entire
surface thereof and thereby communicate to the latter its heat.
The material to be dried or roasted is introduced into the drums through an
opening provided with a sliding lid d. The steam which may be superheated if
required after having passed through the casings which it enters through the
cock 6 and branches a¹ a², re-enters the hollow shaft, at the opposite end thereof,
through the pipe f, and thence passes through a stuffing box into the condenser G
where it is condensed.
In order to obtain the exact degree of heat required, according to the kind of
fruit or material which is being dried or roasted, and to maintain this temperod
temperature (as indicated by a thermometer arranged in combination with the
drum,) the hollow shaft C communicates, by means of the conduit g, with a blower
or ventilator not shown in the drawing, the said blower causing a current of cold
air to enter the drum either at intervals or continuously as may be required,
whereby the temperature may be regulated. The pipe g enters a cylindrical
chamber H through which the hollow shaft C passes, all joints or connections
fitting closely. The said shaft is provided within the chambers H with a number
of openings or perforations through which the blast of air enters into the drum.
In the said hollow shaft are inserted a number of open pipes h provided with
perforations and extending radially in such a manner that the air issuing from the
said perforations is well distributed on entering the drums B and A, the head-plates
of the latter being provided with small perforations to permit the exit of some of
the air.
The pipes h rotating with the said drum or drums do not interfere with the
material to be dried or roasted, which only strikes the said pipes h by its own
weight in passing, without being crushed or injured in any way.
It being possible by simply adjusting the stop valve b to regulate the inflow of
steam into the interior of the casings A B, and, by means of a throttle valve
arranged in the air conduit, to control in a similar manner the quantity of air
forced into the drums from the ventilator or blower, it results that any temperature
required for any material whatsoever to be dried or roasted, say for instance a
temperature of from 65° to 100° Celsius for malt or succory, may be obtained and
maintained in an empirical manner.

page_text: The drying or roasting of the material in question having been completed, the
steam is entirely shut off by closing the stop valve b and the full blast of cold air
admitted from the ventilator so as to thoroughly and completely cool the material
within the said drums.
As shown in the drawing a sliding lid d¹ provided with a number of perforations,
or apertures, the size of which varies according to the character of the material to
be roasted, is arranged below the sliding lid a so that the vapors forming within
the drum, as well as the cool air introduced therein, may be let off more or less
quickly. After sliding back the lid d it is possible to observe the coloring of the
material being roasted, while the drum rotates, and to judge from its appearance
how far the roasting process has advanced. For the same purpose holes filled with
glass may also be arranged on the periphery of the drum, such arrangement being
impossible in the former roasting methods where an open fire was employed.
The inner sides of the drum may be provided with a piece of sheet metal rivetted
thereon edgewise and set diagonally. When the drum is made to rotate, the
material to be roasted is shifted to and fro by the said sheet iron piece, thereby
increasing, in a great measure, the regularity and uniformity of the roasting.
The drum shown in Figure 3, and intended for drying or roasting in the same
manner as above described, differs from the first described construction only in so
far as regards the serpentine pipe or coil described in the said former specification.
According to the present invention it is employed in a somewhat different and
more simplified manner; the arrangement of the air inlet pipes is also somewhat
modified.
The serpentine pipe in this instance is a single one, but is of a correspondingly
enlarged diameter, resting on the supporting bars q*, the latter being secured to
the head plates of the drum A and also by means of bolts p* to the peripheral walls
of the drum.
The steam, which according to the character of the material to be dried or
roasted is either in a superheated condition or at its normal pressure, passes at the
end a into the hollow shaft C, and thence through the pipe a² into the serpentine
pipe B. After having passed through the latter, it again enters the hollow shaft C
through the pipe f¹ and is discharged from the hollow end f of the said shaft. On
the ends of the drum A air chambers H H are here provided which are supplied
with cold air from the ventilator or blower through the pipes g g'. The shaft C
has two hubs II', the flanges of which have perforations or openings and which
rotate at the heads of the air chambers H H. In the said openings are inserted
the perforated pipes h h¹ respectively, the said pipes projecting into the drum at
both ends thereof and being arranged in radiating clusters. The air blast from the
ventilator passes to the material in the drum from these pipes, permeates the said
material and, as the case may be, tempers or reduces its temperature in the same
manner as already described with reference to Figures 1 and 2 after the process of
drying or roasting has been completed and the steam supply cut off.
In Figures 4 and 5 another device is shown, in connection with the device for
supplying a cold air blast, the object of this device being to produce the proper
temperature required for drying or roasting by means of hot water.
With certain materials which require but slow drying or roasting, such as
malt etc, at a temperature of from 60° to 80° Celsius, the contact of such materials
with the serpentine pipe or steam casing, containing steam of from 4 to 6
atmospheres, and hence having a temperature of from 140° to 160° Celsius, and
always above 100° Celsius, may, in some cases, prove injurious to the material.
It is therefore, deemed advantageous in such cases to be able to heat the serpentine
or its equivalent i.e. the steam casing or casings, with water having a maximum
temperature of from 80° to 100° Celsius, instead of using steam for the purpose.
To this end, therefore, a water reservoir K having an inlet pipe i and a discharge
pipe is mounted above the drum A. Now, supposing that it be desired to
suspend the heating with steam and to begin heating with water, all that will be
necessary is to close the stop valve b and to open the valve k¹, whereupon the hot

page_text: water from the reservoir K will, in the same manner as described with regard to
the steam, enter the hollow shaft C, will pass thence through the serpentine
pipe B, and ultimately through the pipe m, the hollow shaft, and the pipe n into a
receptacle L.
A back pressure valve n³ is provided within the pipe n in order to prevent the 5
discharged water from re-entering the latter, and the receptacle L is provided
inside with a float O which slides on a tube surrounding a rod g. The said rod g
has two projections or pegs q¹ q which project from the surrounding tube p, and it
carries an air valve 7 and a pivot 8, the latter being connected with the lever or
handle of the cock t arranged within the receptacle L. A regulating cock u is 1
also provided on the outside by means of which steam may be admitted into the
receptacle L, the said steam entering a finely perforated serpentine pipe v, whence
it is discharged into the water contained in the said receptacle so as to heat the
water. The latter gradually rises in the receptacle L thereby lifting the float O,
the air cock remaining open all the while and the cock t being held closed. On 1
rising to a certain height the float O strikes the upper projection q¹ thereby closing
the air-valve and turning the lever of the cock t until the said cock is opened.
The steam thereupon suddenly entering through the cock t, acts on the water like
a pulsometer, causing the same to rise in the pipe i whence it is again discharged
into the reservoir K until the float strikes the lower projection g', thereby closing :
the cock t again and opening the air-valve r so that the water passing through the
serpentine pipe B and pipe n may again collect in the receptacle L, until the
operation above described is repeated.
When it is desired to heat the water to a very high degree, the regulating
cock u is opened as wide as possible in order to let the steam pass through the
entire length of the serpentine pipe vand to heat the water, in rising, up to boiling
point, it being evident that the smaller the passage through the cock the less of the
length of the perforated serpentine u will be passed by the steam, as the latter will
issue more from the perforations of the upper part of the said serpentine pipe and
will thus have a tendency rather of forcing the water into the reservoir K, than of
heating the same.
The roasting process being completed, the valves ¹ and u are closed, the
ventilator conduits are opened, and a cool blast is introduced by means of the
pipes gg and the hollow shaft C into the drum so as to cool the material therein
quickly.
In such cases where it is desired only to effect a rapid cooling of the roasted
material or to obtain only a slight roasting of the same, the air pipes / communi-
cating with the conduit g and the drum A, and participating in the rotary
movement of the latter, may be arranged in the same manner as described within
a secondary drum constructed of wire cloth or perforated sheet metal and of any
desired sectional shape, the said secondary drum being arranged apart from, and
independently of, the drum A. The material to be dried or roasted, is put into
such perforated or sieve-like secondary drum.
In case raw materials requiring only slight drying are put in the said perforated
or sieve-like secondary drum, it will be found sufficient to connect the ventilator
ducts with a heating chamber and then to blow in hot air first. The drying
process having been completed in this manner, the ventilator and the heating
chainber are disconnected again and a cold air chamber is connected with the
ventilator, so as to cause the hot material to cool quickly.
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
First. The method of drying or roasting cocoa-beans, coffee, malt, succory, or
similar materials which method consists in subjecting, either intermittently or
continuously, the material to be dried or roasted to the action of a temperature
produced by a moving current of steam, and to the action of a moving current of
cooling air or other cooling fluid, or liquid, which allows of tempering and

page_text: regulating the temperature prevailing within the roasting drum, so as to obtain
and maintain therein, the exact temperature required according to the nature of
the material under treatment, substantially as herein set forth, and for the purpose,
specified.
Second. In steam-roasting apparatus for drying or roasting cocoa-beans, malt,
succory, coffee beans or similar materials, the combination with the roasting drum A
of a coil of pipes, or a double steam casing provided with partitions for causing
a circulation of the steam, so connected with steam-conduits that the said coil of
pipes or the steam casing will partake of the rotatory motion of the said drum
when the latter is revolved, substantially as, and for the purpose, specified.
Third. The combination, with the drum A, of the air-pipes for introducing cool
or hot air into the interior of the said drum, and so connected with the latter and
with the air-conduits of a ventilator or blower that they will partake of the
rotatory motion of the said drum when the latter is revolved, substantially as, and
for the purpose, specified.
Fourth. The combination, with the steam-casing or the equivalent system of
steam-pipes arranged within the roasting drum, of the reservoir K arranged above
the latter, and the receptacle L, both being so connected with the said steam-
casing, or its equivalent, by means of the inlet pipe a and the outlet-pipe n that
the said steam-casing or its equivalent can partake of the rotatory motion of the
said drum when the latter is revolved, substantially as, and for the purpose,
specified.
Fifth. The combination, with the revolving drum A, of the receptacle L having
the perforated serpentine pipe connected with a steam inlet pipe, the latter
being controlled by the regulating cock u, and of the stop-cock t and air valve r
controlled by the float O, substantially as, and for the purpose, specified.
Dated this 11th day of December 1884.