Improved Process for Roasting Coffee, Cocoa, Chicory, and Drying Malt or other Materials.
Year: 1894

page_text: Date of Application, 9th Apr., 1894-Accepted, 23rd June, 1894
COMPLETE SPECIFICATION.
Improved Process for Roasting Coffee, Cocoa, Chicory, and Drying
Malt or other Materials.
I, DAVID GROVE, 24 Friedrich Strasse, Berlin, in the Empire of Germany,
Manufacturer, 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 :-
This invention relates to a process for roasting coffee, cocoa, chicory, and drying
malt or other materials, by means of hot-air.
According to this process, the material to be roasted or dried is placed into
closed chambers heated by hot-air circulating in the apparatus without being
renewed; after the air has given off its heat to these chambers, it returns to a
calorifere or heating tube to be re-heated in such manner, that a continuous and
uniform circulation of the same quantity or body of air is effected.
Such a
circulation of air prevents over heating as far as possible, and secures perfect
util zation of the heat.
In treating materials, which are preferably kept in continuous motion, so as to
effect a uniform roasting, or drying, it is essential that the roasting process can be
stopped immediately the materials are completely acted upon. This is effected
either by leading the roasted material from the roasting chambers directly into a
cooling device, or by taking the roasting-chamber out of the hot-air chamber.
In order that the process can be thoroughly understood, I will describe same with
reference to the apparatus shown in the accompanying drawings, in which,
Fig. 1 is an end elevation.
Fig. 2 a vertical section, and
Fig. 3 a longitudinal section of the apparatus.
Fig. 4 is a section of a modified form of the roasting-chamber, rotably mounted.
Fig. 5 is a sectional end elevation of this chamber with the conveyor fixed to
same.
The mantle or casing of the apparatus consists of an upper and lower part. The
lower part encloses the furnace with grater Fig. 3; on the opposite side of the
fire-bridge, the heating gases pass through a ribbed heating-tube or calorifere c,
and escape through an outlet-pipe e in the rear plate or wall d. The chamber
formed by the end-plates b & d, enclosing the fire-box and calorifere or heating
and underneath by the walls u, u', u³, Fig. 2 is in direct communication with
the upper chamber closed by the arching n, such chamber enclosing the chambers a
for receiving the material to be roasted, or dried.
tube C
These archings, like the walls u, u, u³, are preferably filled or covered with
suitable material known as non-conductor of heat.
In the example given in the drawings, these chambers for receiving the material
to he roasted are shown in the form of a pipe a, extending longitudinally across the
apparatus and secured to the walls b¹¹. These walls b₁d, are provided with
frame-like extensions or brackets carrying the bearings for the shaft of the
conveyor k in each chamber a; said extensions or brackets at the same time, forming
the feeding receptacle i and discharge chamber j. Worm-wheels mounted on the
front end of the shafts of each conveyor k, are driven by worms 9 of a single
transverse-shafts, provided with a pulley t. The material to be treated is fed to
each chamber a through pipe leading to receptacle i or all the chambers a may
be fed from one pipe.
Between the central chambers a and the calorifere c, a slightly arched or flat
plate o is inserted, which prevents the hot-air ascending directly from the calorifere,

page_text: and distributes same by causing it to pass to the side. By means of this
arrangement, the hot-air surrounding the chambers a is maintained at a uniform
temperature, and after having given off its warmth to the chambers a, descends to
the calorifere to be re-heated.
When the material has been sufficiently roasted, it should be cooled as rapidly as
possible. For this purpose-with the apparatus shown in the drawings-the roasted
material is discharged from the chambers a through hollow-walled pipes w, which
are kept cool by a stream of water continuously running through same; these pipes
are preferably provided internally with ribs or ridges for increasing the cooling
surface Fig. 3.
For carrying off the gases generated during the process of roasting etc., branch
pipes are connected with each chamber a, and lead to one outlet forming the
passage to the exhaustor. A receptacle or collector connected with this
exhaustor passage, prevents the husks of the coffee, cocoa, etc. being carried off with
the gases.
According to Figs. 4 & 5, the chambers a¹ are so constructed that they rotate
with the conveyor k¹, which, in this instance, is secured to the walls of the
chambers a¹. The roasting gases are passed through the central free passage of
the conveyor k, to the end chamber j', from which they are drawn off through the
:suction pipe v¹.
It will be understood that this process is not restricted to the apparatus shown
and described, which has simply been given as an example. It will be quite evident
that the apparatus may be modified according to the nature of the material to be
treated; for instance, instead of the conveyor and cooling device, the apparatus may
be so constructed that the chamber containing the material can be removed from
the hot-air chamber, after the material is roasted or acted upon.
It is, however, essential to the process that the apparatus be arranged in such
manner, that the chamber containing the material is situated in a closed receptacle
or space provided with a calorifere or heating tube for re-heating the air after same
has given off its heat to the chambers containing the material to be roasted,
or dried, and thus effecting a continuous circulation of the same quantity or body
⚫of air.
Instead of the solid walls as shown in the drawings, slits, holes or the like may
be made in the chambers containing the material to be roasted, thus allowing the
hot-air to circulate through the chambers too.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I.
claim is :-
Improved process for roasting coffee, cocoa, chicory, or drying malt or other
materials by means of hot-air, according to which the chambers receiving the
material to be treated are arranged in a closed hot-air casing and brought to, and
maintained at the proper temperature, by hot-air surrounding said chambers, said
air, after having given off its heat to the latter, returning or circulating to the
calorifere or heating tube to be re-heated, substantially as described.
Dated the 7th day of i11002
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents.