AN IMPROVED METHOD OF AND APPARATUS FOR DRYING COFFEE, GRAIN, FRUIT, AND OTHER MATERIALS
Year: 1880

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in tho
County of Middlesex, Patent Agent, for an Invention of "AN IMPROVED
METHOD OF AND APPARATUS FOR DRYING COFFEE, GRAIN, FRUIT, AND
OTHER MATERIALS." A communication from abroad by Sir Henry Scholfield,
Knight, of the City of Guatemala, in the Republic of Guatemala, Contral
America.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 24th September 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"AN IMPROVED METHOD OF AND APPARATUS FOR DRYING
Coffee, GRAIN, FRUIT, AND OTHER MATERIALS." A communication from abroad
by Sir Henry Scholfield, Knight, of the City of Guatemala, in the Republic of
Guatemala, Central America.
This Invention relates to apparatus for drying or evaporating the moisture from
various materials, such as green coffee, grain, &c., by heated air.
The object of the improvements is to obtain rapidity of action and efficiency of
operation, so that the material shall be properly dried at small expense and without
risk of damage by excessivo heat. Further, the object is to furnish an apparatus
that can be operated by unskilled workmen.
The apparatus consists of a drying chamber (preferably constructed of sheet
metal) fitted with a bottom of perforated material, and a closed top of conical form,
from which rises an escape flue or chimney. The top is fitted with inanholes,
through which the chamber is filled. Beneath the perforated bottom is a steam
coil connected with a suitable generator, and in the escape fluo is fixed an aspirator,
that is also connected with the steam generator. Steam being admitted to the
coil and to the aspirator the air is drawn upward through the coil, by which it is
heated, and passes through the material and out by the flue, thereby extracting and
carrying off the moisture from the material.
In the accompanying Drawing forming part of this Specification the drying
apparatus as arranged in a convenient form is shown by a sectional elevation. A is
the drying chamber fitted on a suitable stand B; C is the escape fluo or chimney
containing the aspirator D; E is a steam generator connecting by pipes a, b, with
coil F, and by pipe c with the aspirator D. The drying apparatus is shown as
elevated above the generator to obtain the aid of gravity to return the water of
condensation from the coil F to the generator, but it is evident that the same
result can be obtained by placing the chamber at the ground level and sinking the
generator. In some cases this may be preferable to give convenient access to the
chamber for filling and discharging. The chamber A is constructed of sheet metal

page_text: in rectangular form and of suitable size, according to the amount of material it is
desired to treat at once. The bottom & is made of wire cloth or other perforated
material, which bottom is fixed in place a short distance above the lower edge of
the chamber, so that there is an enclosed space beneath the bottom, in which the
coil F is placed. The top e of the chamber is rigidly secured, and is made in the
pyramidal form shown, or highest at the centre, from which the flue or chimney C
rises. In the cover e are openings fitted with plates or doors f that are arranged
for being closed air-tight. These openings are for use in filling the chamber with
the material to be dried. In the chamber, a short distance below the cover, is a
screen g, up to which the material will be filled, so that there is an air space, as
shown, left beneath the cover. This screen has openings fitted with removable
covers beneath the plates f. In one side of chamber A, just above the bottom d, is
an opening for the discharge of the material provided with a hinged door, as shown
át h in dotted lines. The base of chimney C is enlarged to receive the aspirator D,
which latter is made in any desired form on the principle of a steam injector. The
upper part of the aspirator connects with the chimney, while from the lower end
the steam pipe c passes to the generator, so that steam admitted to the aspirator
passes up and out at the chimney, and acts to draw the air in the upper part of
the chamber A through the sides of the aspirator to the chimney, thereby creating
a partial vacuum and a suction of air through the mass in the chamber. The
-effect.is to draw the air in vertical currents through the material to take the place
of the exhausted air in the air space above screen g, so that every portion of tho
material is subjected to the action of the heated air equally. The air drawn in at
the bottom is heated-by-coil-F,-through which the steam circulates. The action is
-automatic.as.regards the beat of the coil and the rapidity of air movement, for-the-
reason that excessive steam pressure and increase of heat-thereby-will-be.balanced_
by the increased draft created by the increased pressure of steam in the aspirator.
It will be seen that skilled labor is not required to operate the apparatus after it
is properly set up; it is only necessary to fill the chamber and turn on the steam.
The condition of the material will be indicated by the heat of the outer surface of
the chamber, which, as the material dries, becomes heated gradually, commencing
at the bottom and extending to the top, when the operation is complete.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as new and desire to secure by Letters
Patent is,-
1st. The drying apparatus consisting of closed chamber A provided with
perforated bottom, closed top e, and chimney C, and having combined with it a
steam coil beneath the bottom, steam aspirator placed in the chimney, and a
suitable steam generator, substantially as shown and described for operation, as sct
forth.
2nd. In drying apparatus the combination with chamber A having the pyramidal
top e, chimney C, and perforated bottom d of the screen g and steam aspirator D,
substantially as and for the purpose set forth.
3rd. The described method of drying coffee, grain, and other material in mass,
which consists in drawing previously licated air through a chamber containing the
material by exhaustion of the air in the chamber, substantially as set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty fourth day of September, in the year of
our Lord One thousand eight hundred and eighty.