IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS EMPLOYED FOR ROASTING COFFEE AND OTHER ARTICLES."
Year: 1880

page_text: LETTERS PATENT to Peter Pearson, of Manchester, in the County of Lancaster,
for an Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS
EMPLOYED FOR ROASTING COFFEE AND OTHER ARTICLES."
PROVISIONAL SPECIFICATION left by the said Peter Pearson at the Office
of the Commissioners of Patents on the 11th June 1880.
PETER PEARSON, of Manchester, in the County of Lancaster.
"IMPROVEMENTS
IN THE CONSTRUCTION OF APPARATUS EMPLOYED FOR ROASTING COFFEE AND
OTHER ARTICLES."
This Invention relates to the construction of apparatus used for roasting coffee,
chicory, cereals, or other like articles required to be roasted, and applies more
particularly to that class of apparatus which has hitherto been used only for
roasting chicory, and which consists principally of a shallow revolving pan which is
placed in a chamber beneath a fire; the object of the present Invention being to
improve the construction and operation of such apparatus, and more especially to
render it suitable for roasting coffee and other grains.
Hitherto it has not been found practicable to roast coffee or other grain by
means of this apparatus in consequence of the action of the centrifugal force
throwing the grain outwards towards the edge of the pan, and thus causing the
inner layer (or that nearest the centre) to become very thin, whilst the outer layer
(or that near the edge of the pan) became proportionately thick, and hence the
inner portion became over roasted or burned before the outer portion was
sufficiently roasted, and hence it was impossible to roast the coffee equally.
My improvements are designed to remedy these defects by, firstly, so counteracting
the effects of centrifugal force as to cause the layer of coffee or other grain to be
always equally and evenly distributed over the whole surface of the pan; and,
secondly, by preventing the burning or over roasting of the inner layer (or that
nearest the centre) which would otherwise still occur, notwithstanding the evenness
of the layer, in consequence of the centre part of the pan moving at a less velocity
than the part nearer to the circumference.

page_text: In the first place I employ in the interior of the revolving pan a series of fixed
scrapers, which are placed at such an angle as will have a constant tendency, whilst
the pan is revolving, to throw the coffee or other grain towards the centre, and
thus the effects of the centrifugal force will be counteracted, the coffee or grain will
be well stirred, and the layer kept always level and even.
And, secondly, in order to prevent the burning or over roasting of that portion
of the coffee or grain which, being nearer to the centre, moves at a lower velocity,
I employ a ring of metal which keeps the centre of the pan quite clear, and a fixed
screen or cover of sheet metal placed over the centre part of the pan which screens
off a portion of the heat of the fire from the coffee or grain, by which means the
whole contents of the pan are equally roasted. And it will be found in practise
that not only will the coffee or other grain be more equally roasted by the use of
this apparatus, but a greater proportion of the volatile parts, including the aroma,
will be retained, and the weight of the coffee or other grain will not be so much
reduced in roasting as by the use of the apparatus hitherto employed.

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 10th December
1880.
PETER PEARSON, of Manchester, in the County of Lancaster.
"IMPROVEMENTS
IN THE CONSTRUCTION OF APPARATUS EMPLOYED FOR ROASTING COFFEE AND
OTHER ARTICLES."
This Invention relates to the construction of apparatus used for roasting
chicory, cereals, or other like articles requiring to be roasted, and applies more
particularly to that class of apparatus which has hitherto been used only for
roasting chicory, and which consists principally of a shallow revolving pan which is
placed in a chamber beneath the fire; the object of the present Invention being to
improve the construction and operation of such apparatus, and more especially to
render it suitable for roasting coffee and other grains.
Hitherto it has not been found practicable to roast coffee or other grain by
means of this apparatus in consequence of the action of the centrifugal force
throwing the grain outwards towards the edge of the pan, and thus causing the
inner layer (or that nearer the centre) to become very thin, whilst the outer layer
(or that near the edge of the pan) become proportionately thick, and hence the
inner portion became over-roasted or burned before the outer portion was
sufficiently roasted, and hence it was impossible to roast the coffee equally.
My improvements are designed to remedy the above mentioned defects by, firstly,
so counteracting the effects of centrifugal force so as to cause the layer of coffee or
other grain to be always equally and evenly distributed over the surface of the
pan; and, secondly, by preventing the burning or over roasting of the inner layer
(or that nearest the centre) which would otherwise still occur, notwithstanding the
evenness of the layer, in consequence of the centre part of the pan moving at a less
velocity than the part nearer to the circumference.
Such being the nature and object of my said Invention, I will now proceed to
describe more in detail the manner in which the same is to be or may be performed
or carried into practical effect, and in order that the same may be clearly understood,
I have annexed hereunto a Sheet of Drawings illustrative thereof, and have marked
the same with figures and letters of reference corresponding with those in the
following explanation thereof:-
Fig. 1 in the annexed Drawings is a front elevation of my improved apparatus
with the doors of the roasting chamber shown as open; Fig. 2 is a vertical section
through, about, the line A, B, in Fig. 1.
Fig. 3 is a plan view of the same, with the top flue partly removed, and Fig. 4 is
a plan view of the pan lid or cover detached; a, a, is the furnace, and b, b, the
flue, passing above the roasting chamber c, c, which is provided with doors d, d.
The revolving pan e, e, is supported on a carriage f, f, running upon rails g, g, and
is caused to revolve when in the roasting chamber by the bevel wheel h, h, falling
into gear with the pinion i, i, which is constantly revolving.
So far the apparatus is (as previously mentioned) similar to that sometimes used
for roasting chicory, but in order to adapt the same to the purposes of my Invention,
I make the following modifications:-
In the first place I employ in the interior of the revolving pan e, e, a series of
scrapers j,j, which are fixed to the pan cover l, l, and which are placed at such
an angle (see Fig. 4) as will have a constant tendency, whilst the pan e, e, is
revolving, to throw the coffee or other grain towards the centre, and thus the effects
of the centrifugal force will be counteracted, the coffee or grain will be well stirred,
and the layer kept always level and even; and, secondly, in order to prevent the
burning or over-roasting of that portion of the coffee or grain which, being nearer

page_text: to the centre, moves at a lower velocity, I employ a ring of metal m, m, which
keeps the centre of the pan quite clear, and a fixed screen or cover l, l, of sheet
metal placed over the centre part of the pan, which screens off a portion of the
heat of the fire from the coffee or grain, by which means the whole contents of
the pan are equally roasted. And it will be found in practise that not only will
the coffee or other grain be more equally roasted by the use of this apparatus, but
a greater proportion of the volatile parts, including the aroma, will be retained,
and the weight of the coffee or other grain will not be so much reduced in roasting
as by the use of the apparatus hitherto employed.
The outer portions of the screen or cover at n, n, may either be left open, as
shown at Fig. 4, or filled in with wire gauze, as shown at Fig. 3, in which case a
feed opening must be provided, as at k. It will be understood that the screen or
cover l, l, does not revolve, but is fixed to the pan carriage f, f, by the uprights o, o,
and that the scrapers j, j, being fixed to the cover, are also stationary.
In order to prevent the coffee from burning by being kept continually against
the ring m, m, one or more of the scrapers j', immediately next to the said ring,
are turned in the reverse direction, and the scrapers j' being close against it will
throw the coffee outwards again, and thus all the coffee will be constantly turned
over and over.
Having now described the nature and object of my 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 the novel and
peculiar construction of apparatus for roasting coffee and other grain, as herein-
before described and illustrated by the Drawings annexed, and more especially I
claim the construction and application of the central ring of metal m, m, or its
equivalent, to keep the centre of the pan clear; the screen or cover l, l, to prevent
the burning or over-roasting of the coffee or other grain, and the fixed scrapers j,
for throwing the coffee or grain towards the centre of the pan, and the scrapers j¹
for throwing it outwards from the ring.
In witness whereof, I, the said Peter Pearson, have hereunto set my hand
and seal, this Thirtieth day of November, in the year of our Lord One
thousand eight hundred and eighty.