IMPROVEMENTS IN APPARATUS FOR DRYING AND HEATING GRANULAR OR PULVERULENT MATERIALS
Year: 1884

page_text: I PIERRE ANATOLE FICHET of Paris in the Republic of France, Engineer,
do hereby declare the nature of my Invention for IMPROVEMENTS IN APPARATUS
FOR DRYING AND HEATING GRANULAR OR PULVERULENT 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 has for its object an improved apparatus or furnace which is
capable of being employed with advantage in all cases where it is required to
subject granular or pulverulent materials such for example as grain, berries plaster
chemicals or other substances to the action of an elevated temperature and it
consists in the peculiar construction and arrangement of the parts as hereinafter
described whereby a regular and equal distribution of the heat is obtained together
with facility for controlling or regulating the temperature. The materials treated
in the improved apparatus are also subjected to a graduated or progressive drying
and heating and the latent heat in the products issuing from the furnace is
utilized for heating air which is subsequently employed for drying the materials
entering the apparatus and for supporting combustion.
And in order that my said Invention may be fully understood. I shall now
proceed more particularly to describe the sanie and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings is a vertical section of an apparatus
constructed according to this Invention. The right hand portion of this Figure
represents a section taken along the line 1, 2 Figure 2 the left hand portion being
a section taken along the line 3, 4 Figure 2.
Figure 2 is a vertical section taken at right angles to the section in Figure 1,
the right hand part of the section in Figure 2 being taken along the line 5, 6
Figure 1 whilst the left hand part represents a section taken along the line 7, 8
Figure 1.
The apparatus is constructed with a series of vertical columns or chambers H
forming vertical passages in which the materials are dried and heated. These
chambers are ranged at the sides of a fireplace or combustion chamber E and are
enclosed in a suitable casing P provided with air passages and flues as hereinafter
described.
The granular or pulverulent materials are supplied at the upper part of the
apparatus and are discharged at the lower part after passing during their descent
through a grating R which arrests the large pieces and foreign bodies, a drying
zone D, where the materials are exposed to the action of hot air, a preparing
zone B, a baking zone A, and a cooling zone C.

page_text: I prefer to employ the fuel or heating agent in the form of a gas such as oxide
of carbon obtained from a gas producer but solid or liquid fuels may be employed
in the improved apparatus. The fire place E extends the entire length of the
apparatus and is constructed with a passage or chamber E¹ which receives the
heating or fuel gases and distributes them to a series of adjustable orifices or
burners F supplied with hot air through passages or flues G.
When solid fuel is employed the chamber E acts as a gas producer the bottom
being arranged in the form of a grate and the adjustable orifices F then serve to
regulate the production of flame and cause it to be uniformly distributed in the
apparatus.
In order to ensure a uniform distribution of the heat throughout the apparatus
the products of combustion from the burners F are first caused to rise vertically in
contact with the external walls of the lower part of the hollow columns H
constituting the baking zone A hereinbefore referred to and then being arrested in
their ascent by a horizontal partition Q are deflected and caused to descend as
indicated by the arrows and enter vertical passages or flues H₁ formed in the
centres of the said columns as hereinafter described. On issuing from these
vertical passages the heating gases escape through lateral orifices L above the
partition and after heating the columns externally in the preparing zone B
escape into a chimney O at the upper part of the apparatus.
The gases in the combustion chamber are not allowed to come in direct contact
with the materials which are enclosed in the columns or shafts H heated both
internally and externally the materials occupying an annular space I so arranged
as to facilitate the escape of any gases that may be evolved during the operation as
hereinafter described. The products of combustion are utilized under the most
favorable conditions being caused to circulate in the first place in the baking
zone A and being subsequently employed, after they have thus parted with a
certain amount of heat, to heat the preparing zone B.
The materials that are to be treated in this apparatus are placed on a grating R
which serves to prevent large lumps or foreign bodies from entering the columns H
The materials that pass through the grating R are received in the drying chamber
or drying zone D. Hollow spaces are formed in the mass of materials in this
drying chamber by means of perforated plates or tubes or inverted troughs d
whereby a number of hollows or passages are formned enabling the heated air to act
effectually upon the materials as they slide downwards in the interstices between
the said inverted troughs and at the same time a clear passage is provided for the
escape of the gases or vapours evolved by the materials undergoing the process of
desiccation. The drying process is accelerated by employing perforated sheet iron
för the construction of the plates or inverted troughs d and the hot air is also
enabled to permeate the mass more thoroughly.
The air issuing from the drying zone passes into a discharge flue or chimney o
preferably arranged near to the chimney O, through which the products of
combustion escape, thereby utilizing the heat of the latter chimney to promote the
draught of air used in the drying operation.
or
As hereinafter described the air is heated by passing between chambers J J at
the lower extremities of the columns H each of which columns as indicated in
the Drawing communicates at the lower part into two narrow chambers
compartments-This part of the apparatus is enclosed in a metal casing S at the
Jower edge of which cold air enters and after being heated by contact with the
sides of the chambers J J passes partly to passages M M Figure 1 leading to the
drying chamber and partly to the passages G which lead to the combustion
chamber E. The distribution of the air thus heated by the latent heat in the
materials leaving the apparatus is regulated as required by means of suitable
valves or dampers. This system of drying effects a great saving of fuel and also
presents the special advantage that the heat employed for the drying is obtained
from a source independent of the heat of the combustion chamber. It is well
known that in practice it is impossible to ensure that the materials to be treated

page_text: shall always contain a uniform amount of moisture and (in apparatus where the'
drying is effected by means of the products of combustion) whenever drier
materials than usual are introduced into the apparatus the action of the latter is
disturbed and the temperature immediately becomes excessively high.
By employing a drying chamber heated from an independent source of heat the
conditions are altered, the hot dry air from the cooling chambers J. J is always of
the same temperature and being supplied largely in excess imparts the same equal
temperature to the materials passing through the drier whether the latter be dry
or moistened to any degree. The effect of this is that the apparatus is supplied
with materials of uniform dryness whereby its efficient and regular action is
promoted.
The materials discharged from the drying chamber or zone D are received in
the preparing chamber or zone B and thence descend into the baking chamber or
zone A where they are exposed to a more intense heat than in the preparing
zone. The preparing and baking zones of the columns H are so constructed
and arranged as to enable the gases or vapours evolved from the materials
during the heating operation to escape with facility. With this object these.
columns are made with a solid or unperforated outer casing of circular or
other suitable form in section and are provided internally with a central
passage H formed by a series of sections in the form of inclined annular plates
or truncated cones h engaging to a certain extent one within the other but
maintained at a suitable distance apart by means of vertical distance pieces or
bars to or on which they are rivetted or supported in the proper position.
A free passage for the escape of the gases or vapours is thus provided at the
intervals between the adjacent cones or plates h and the inclination of the sides of
the said cones or plates prevents the smoke or products of combustion from mixing
with the materials which are enclosed in the annular space I formed between the
plates and the sides of the columns H.
The heated products are discharged from the annular passages I into the narrow
chambers or compartments J J hereinbefore referred to acting as coolers and
around or between which a current of air is caused to circulate so as to carry off
the excess of heat. The hot air thus produced is conducted to the drying zone D
at the upper part of the apparatus and is there utilized as herein before described
for effecting a preliminary drying of the fresh materials entering the apparatus.
The compartments or cooling chambers J are provided with valves j through
which the materials may be withdrawn as required preferably at regular
intervals.
These furnaces or apparatus may be constructed of any suitable dimensions
according to the nature and quantity of the materials to be treated in a given
time. The shape height section and number of the columns may be varied as
required and the columns may be arranged in two rows as indicated in the Drawing
or otherwise. The facility afforded by this construction of apparatus for regulating
or varying the duration and intensity of the heating enables the apparatus con-
structed according to this Invention to be applied to a large variety of purposes.
Amongst these may be mentioned the torrefication of grain, almonds and berries
such as coffee cocoa and other analogous substances, drying malt or mouldy or
damaged grain, baking plaster, calcining alunite, earths, ochres, and other mineral
substances carbonizing bones and revivifying animal charcoal treating fertilisers
and the like. In general terms it may be said that the improved apparatus may
be employed with advantage whenever it is necessary to subject to the action of
heat any granular or pulverulent matter capable of descending the annular passages
in the columns.
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 general construction and arrangement of the improved heating
apparatus or furnace for effecting the regular and progressive or graduated drying

page_text: and heating of granular or pulverulent materials substantially as hereinbefore
described and illustrated in the accompanying Drawings.
Second. In apparatus for drying and heating granular or pulverulent materials
causing the materials to pass successively through a series of compartments or
zones constructed and arranged as hereinbefore set forth and wherein the said
materials are subjected to a graduated and progressive drying heating and
cooling substantially as hereinbefore described with reference to the accompanying
Drawings.
Third. Constructing apparatus for drying and heating granular or pulverulent
materials in such a manner that the latent heat in the products leaving the
apparatus is utilised to heat the air employed for the preliminary drying of the
materials substantially as herein before described and illustrated in the accompanying
Drawings.
.
Fourth. In apparatus for drying and heating granular or pulverulent materials,
the employment of hollow columns provided with a central passage constituted by
a series of hollow truncated cones or inclined annular plates entering to a certain
extent one within the other and maintained at a suitable distance apart so as to
present a series of annular inclined openings for the escape of the gases and
vapours evolved by the said materials all substantially as hereinbefore described
and illustrated in the accompanying Drawings."
Fifth. In apparatus for drying and heating granular or pulverulent materials
the combination of the combustion chamber E extending the whole length of the
furnace with the gas supply passage or gás producer E' and air passages G whereby
an equal distribution of the heat in all parts of the apparatus is effected
substantially as hereinbefore described and illustrated in the accompanying
Drawings.
Sixth. In apparatus for drying and heating granular or pulverulent materials
the employment of drying chambers at the upper part of the apparatus covered
by a grating and provided with transverse tubes or plates forming inverted troughs
whereby the materials are effectually exposed to the action of the hot air and the.
escape of the vapours and gases evolved by the materials during the drying
operation is facilitated substantially as herein before described and illustrated in
the accompanying Drawings.
Seventh. In apparatus for drying and heating granular or pulverulent materials
the employment of hollow columns provided at the lower part with passages for
the admission of the heating medium to the central passages in the columns in
combination with chambers communicating with the annular spaces in the said
columns and so arranged as to heat the air employed in drying the materials
substantially as hereinbefore described and illustrated in the accompanying
Drawings.
Eighth. In apparatus for drying and heating granular or pulverulent materials,
causing the heated products leaving the apparatus to heat air employed for drying
the materials entering the apparatus and for supporting the combustion in the
fire-place or combustion chamber, substantially as hereinbefore described and
illustrated in the accompanying Drawings.