IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR ROASTING COFFEE OR OTHER VEGETABLE SUBSTANCES."
Year: 1881

page_text: LETTERS PATENT to Peter Pearson, of Manchester, in the County of Lancaster,
for an Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS
FOR ROASTING COFFEE OR OTHER VEGETABLE SUBSTANCES."
PROVISIONAL SPECIFICATION left by the said Peter Pearson at the Office
IMPROVEMENTS
of the Commissioners of Patents on the 25th February 1881.
PETER PEARSON, of Manchester, in the County of Lancaster.
IN THE CONSTRUCTION OF APPARATUS FOR ROASTING COFFEE OR OTHER VEGETABLE
SUBSTANCES."
The object of this Invention is to construct an apparatus for roasting coffee or
other vegetable substances which shall be both automatic and continuous, so that
the coffee is fed in the raw state into one end of the apparatus, and is discharged
roasted at the other; the aroma is also preserved and the weight only very slightly
diminished.
The apparatus consists principally of a long trough of a semi cylindrical section
in which revolves slowly a worm or screw, the upper part being enclosed by a
semi cylindrical cover of wire gauze, above which is a long metal plate which is
kept at a red heat.
A hopper for supplying the raw coffee is provided at one end, and an opening
and shoot at the other for discharging the roasted grain.
In order to keep the coffee well stirred during the roasting operation a series of
longitudinal wires are threaded through the coils of the screw in a direction parallel
to the axis so as to form a kind of cage, and these wires are constantly stirring
up and turning over the coffee as the coils of the screw carry it'slowly towards the
discharging end of the trough.
•
The top plate is kept red hot by means of a series of gas jets above the same,
the effect of the gas being increased by placing lumps or balls of fire-clay or
asbestos, or other suitable material above the iron plate, and allowing the gas jets
to impinge thereon, the whole being enclosed in a long box or chamber made of
iron, brickwork, or other suitable material.
Instead of the longitudinal wires above described I sometimes employ pins or
projections cast on or otherwise fixed to the face of the coils.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Pearson in the Great Seal Patent Office on the 25th August
1881.
PETER PEARSON, of Manchester, in the County of Lancaster.
"IMPROVEMENTS
IN THE CONSTRUCTION OF APPARATUS FOR ROASTING COFFEE OR OTHER VEGETABLE
SUBSTANCES."
The object of this Invention is to construct an apparatus for roasting coffee or
other vegetable substance which shall be both automatic and continuous, so that
the coffee is fed in the raw state into one end of the apparatus, and is discharged
roasted at the other; the aroma is also preserved and the weight only very slightly
diminished.
The apparatus consists principally of a long trough of a semicylindrical section
in which revolves slowly a worm or screw, the upper part being enclosed by a
semi-cylindrical cover of wire gauze, above which is a long curved metal plate
which is kept at a red heat.
A hopper for supplying the raw coffee is provided at one end, and an opening at
the other for discharging the roasted grain.
In order to keep the coffee well stirred during the roasting operation a series of
longitudinal wires are threaded through the coils of the screw in a direction
parallel to the axis so as to form a kind of cage, and these wires are constantly
stirring up and turning over the coffee as the coils of the screw carry it slowly
towards the discharging end of the trough.
The top plate is kept red hot by means of a series of gas jets above the same,
the effect of the gas being increased by placing lumps or balls of fire clay or
asbestos or other suitable material above the iron plate, and allowing the gas jets
to impinge thereon, the whole being enclosed in a long box or chamber-made of
iron, brickwork, or other suitable material.
Instead of the longitudinal wires above described I sometimes employ pins or
projections cast or otherwise fixed to the face of the coils.
In the annexed Drawing, Fig. 1 is a longitudinal section; Fig. 2, a transverse
section, and Fig. 3 an end view of one form of my improved apparatus. a, a, is
the trough supported on brickwork b, b, and having fitted in the interior a screw
or worm c, c, the shaft d, d, of which is mounted in suitable bearings e, e, and is
caused to revolve slowly by means of a band passing around one of the pulleys f, ƒ,
or by any other suitable means; g, g, is a semi-cylindrical cover of wire gauze
enclosing the upper half of the worm so as to prevent the coffee or other substance
to be roasted from coming into actual contact with the red hot plate h, h, which is
kept heated by the gas jets i, i; k, k, represent lumps of fire clay or other
refractory substance; 1, 1, is the hopper for supplying the coffee or other substance,
and m, m, the opening for discharging the same roasted..
n, n, are openings at one end for the admission of air to support combustion, and
o, o, is a pipe at the other end for the escape of the unconsumed products of
combustion.
.
Fig. 4 is a longitudinal section, and Fig. 5 a transverse section of a slightly
modified form of the apparatus.
In this case the screw c, c, is surrounded by a cage r, r, of wire gauze (see
detached section, Fig. 6), each end of which is attached to a rim wheel 8, 8, running
loosely upon the axle or shaft d, d, one of the wheels 8, 8, being cast with a long
boss or sleeve, on the outer end of which is keyed a driving pulley p, p.
The gas
jets i, i, are also placed inside the top curved plate h, h. The screw c, c, and the
cager, r, are both driven in the same direction, but the latter is driven much

page_text: faster than the former, the rapid revolution of the cage r, r, turning the coffee
over constantly, whilst the slow revolution of the screw c, c, moves it gradually
along towards the discharge opening m, m. In this arrangement the longitudinal
wires c', c¹, may be entirely dispensed with, or only partially so, as shown on the
Drawings. In order to prevent the accumulation of dust or other matter which
may fall through the gauze cage r, r, into the trough a, a, I make a long opening
therein which I close by a hinged or sliding door q, q, which may be opened in
order to clean out the trough; or an opening or slot may be formed along the
bottom of the said trough a, a, and any dust or other matter falling from the
cage r, r, would fall through this opening.
Having now described the nature and object of the said Invention, together
with the manner in which the same is to be or may be performed or carried into
practical effect, I wish it to be understood that I claim as my Invention in an
apparatus for roasting coffee or other vegetable substance.
First. The combination of a slowly revolving screw or worm in a semi-cylindrical
trough with a curved metal plate above heated by gas or other analogous
means.
Secondly. I claim the combination with a slowly revolving screw or worm (on a
semi-cylindrical trough) of a quickly revolving cage of wire gauze enclosing the
same; also with a curved metal plate above heated by gas or other analogous
means, all substantially as hereinbefore described and illustrated by the Drawings
annexed.
In witness whereof, I, the said Peter Pearson, have hereunto set my hand
and seal, this Seventeenth day of August, in the year of our Lord One
thousand eight hundred and eighty one.
PETER PEARSON. (L.S.)