IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR TORREFYING GRAIN AND OTHER SEEDS, PART OF WHICH APPARATUS IS APPLICABLE FOR OTHER HEATING PURPOSES "
Year: 1883

page_text: LETTERS PATENT to John Fordred of Tottenham in the County of Middlesex
Technical Chemist for an Invention of "IMPROVEMENTS IN THE CONSTRUCTION
OF APPARATUS FOR TORREFYING GRAIN AND OTHER SEEDS, PART OF WHICH
APPARATUS IS APPLICABLE FOR OTHER HEATING PURPOSES
"
PROVISIONAL SPECIFICATION left by the said John Fordred at the Office
of the Commissioners of Patents on the 28th December 1883.
JOHN FORDRED of Tottenham in the County of Middlesex Technical Chemist,
"IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR TORREFYING GRAIN
AND OTHER SEEDS, PART OF WHICH APPARATUS IS APPLICABLE FOR OTHER
HEATING PURPOSES.
"
The chief object of my invention is to provide a simple and cheap means of
torrefying grain or seeds for various purposes, but more especially for use in
Breweries, Distilleries and Vinegar Works.
Previously to the passing of the new Beer Act, which came into operation on
the 1st October 1880, malted Barley was the chief material used in Breweries for
the production of Beer and paid a beavy Excise duty, popularly known as the
Malt Tax, which tax had existed in some form or other in the United Kingdom for
more than 200 years.
The new Beer Act 43 and 44 Vict. cap. 20, introduced and passed by the
Government of Mr W. E. Gladstono rendered it possible to use raw grain in
Breweries as a partial substitute for malt in the same manner as had heretofore
been permitted in Distilleries and Vinegar Works but it was soon found that raw
grain (that is, grain unprepared in any way) was unsuited for the production of a
pleasant Beer, and it became necessary to find some mode of treating the raw grain
in order to remove this objection.
Up to the present time the best devised method of preparation appears to be
that of torrefying or partially torrefying the grain or cereal intended to be
employed for such purposes in the manner described in the specification of a
Patent granted to me and bearing date the 8th day of November 1881, N° 4891.
In that specification I refer to a modification of the ordinary Coffee Roasting
apparatus, but I have since found by experiment that the form of apparatus which
constitutes the subject of the present invention is better adapted for the purpose of
torrefaction or partial torrefaction of any grain or seed, whether intended to be used
for Brewing, Distilling Vinegar making or other purposes.

page_text: The process of torrefaction being one of extreme delicacy it is absolutely
necessary that it should be under perfect control, for which purpose it is requisite
to provide what may be called "an instrument of precision" in which each
individual grain can be uniformly acted on by the heat employed which has
hitherto been difficult when operating upon grain in bulk.
The most perfect machine for this purpose would seem to require that the
individual grains or seeds should be kept in contact with a heated metallic surface
whilst at the same time they are kept in constant motion. This effect is best
produced by causing the grain to pass from end to end of a heated rotating helical
coil, which may be formed in various ways either by threading a series of cast
metal segments on a central hollow shaft or by coiling a tube round such a shaft,
or by preference constructing a helical coil of wrought iron discs with a copper
skin, as I am about to describe.
Several such kinds of apparatus have been proposed by other inventors for
somewhat similar purposes, but none of them have given practical directions for
their construction, and at the present time no machine of the kind is in use for
roasting or torrefying cocoa, coffee, chicory, or the like.
One of the great difficulties in constructing such a machine is to provide a means
of access to the interior of the helical coil, for the purpose of removing any
accumulation of grain caused by overheating or otherwise. This is impossible in
the case, for instance, of a coiled tube, and very difficult where cast metal segments
are threaded on a central shaft.
To meet all these difficulties, I now provide a rotary cylinder made preferably of
sheet copper, and closed at its ends by plates of cast iron. This cylinder I fit with
a helix formed of moulded circular plates of sheet metal set upon a hollow wrought
iron shaft helically grooved to receive the moulded plates. These plates are turned
up in a lathe before insertion in place (in the manner hereafter described) and they
are secured together to form a helix by means of fish plates set at their backs.
The shaft of the rotary cylinder is mounted in bearings in standards which also
serve to support air-gas burners for heating the cylinder. These burners extend
from end to end of the copper cylinder which is enclosed in a double casing
packed with filamentary asbestos or with silicated cotton, for the purpose of
retaining the heat generated by the burners.
This casing is made in two parts, the lower part being fixed, and the upper part
(which is slotted from end to end) removable to facilitate access to the cylinder.
The casing has a longitudinal opening at bottom to allow the gas flames to play
upon and around the copper cylinder and the upper slot is fitted with a damper
valve extending from end to end of the casing for the purpose of regulating the
temperature within.
The cylinder is fed with grain through the periphery of one of its end plates,
which plate underlies a saddle fixed to the casing or to the adjacent standard and
on which the hopper is mounted.
The supply of the grain is regulated by a slide in the delivery neck of the
hopper and the discharge of the grain is through an opening in the periphery at
the opposite end of the cylinder, below which opening is a shute for guiding the
grain into a suitable receiver.
In constructing the helix I have said that I use moulded plates of sheet metal:
I will now proceed to describe more in detail the mode of constructing the helix.
I first cut out from sheet metal, preferably wrought iron, a sufficient number of
discs say 18 inches in diameter with a central opening of say about nine inches in
diameter, and these discs I slit radially. Having thus prepared them I heat them to
a red heat and subject them singly to pressure in a pair of cast iron dies to bring
them into the proper helical form. When thus shaped I pile a given number of
these plates together gripping them between the dies, one of which has previously
been secured to the face plate of the lathe. I then bore out the centre of the helical
plates to fit the helical groove of the hollow shaft and I afterwards turn and true
up the outer edges of the helical plates. When these are inserted in the helical

page_text: groove of the shaft an connected by fish plates as above explained, they form
with the outer skin of copper a steam tight helical passage.
This skin is composed of two or more breadths of thin sheet copper to form its
length the pieces being lapped with the joints so arranged as to avoid any
obstruction to the travelling grain. The periphery of the cylinder may be formed
by one or more pieces of sheet copper their edges standing longitudinally, lapping
to secure a close joint that will present no obstruction to the grain. Upon these
pieces near their lapping edges I rivet longitudinal L-shaped metal strips in which
I drill holes to receive connecting and tightening bolts; by tightening these bolts
by means of nuts, the sheets composing the copper cylinder are drawn tightly
around the helix and form therewith a helical passage for the travel of the grain.
The shaft of the cylinder is fitted with suitable riggers for driving the same
and the hopper being charged and properly regulated a determined supply of
grain will be delivered into the first compartment of the cylinder at each
revolution.
The burning of the gas below the cylinder in regulated quantity will roughly
determine the degree of heat that is imparted to the cylinder the closer regulation
being effected by the position of the damper valve on the outer casing, and by
adjusting the distance between the burners and the cylinder.
As the cylinder is rotated the grain will pass along the internal heated surface
of the copper skin, its degree of torrefaction being determined by the operator
who can increase or diminish at pleasure the supply of gas to the burners and the
rate of travel of the grain through the apparatus. As the torrefied grain reaches
the end of its course, it falls through the opening at the end of the cylinder into
the shute below, and thence into the receiver.
The construction of burner which I prefer to employ may be thus described.
An iron tube is provided with a parallel slot through its upper side of a length
equal to half the length of the cylinder to be heated; both ends of this tube are
closed, and its outer end which constitutes a mixing chamber is fitted with a gas
jet set concentrically in the tube. Immediately below this jet an opening is made
in the tube for the admission of air thereto and this opening is protected by a
wind guard. Thus the air and gas commingle and fill the mixing chamber
preparatory to entering the slotted portion of the tube.
The longitudinal slot is covered by a strip of wire gauze and the gas pipe is
furnished with a cock which carries a dial or pointer for indicating as the cock is
turned the rate of supply of gas admitted to the burner.
This construction of burner ensures an equable and regular supply of the mixed
gases throughout the whole length of the slot and the consequent maintenance of
any determined degree of heat.
I propose to fit the machine with two burners of this description set end to end,
each receiving its own supply of the mixed gases, which issuing through the
narrow longitudinal slot, give when ignited a flame three to four feet in length,
thus constituting an entirely novel kind of gas burner which is also applicable
wherever a limited and uniform temperature for heating an extended surface is
required.
Besides regulating the heat through the gas supply cocks, I propose also to give
the burners a vertical adjustment by their supports and thus to cause the flame to
advance to or recede from the under surface of the rotating cylinder.
In this improved machine it will be seen that the operator has three means of
regulating the torrefaction viz:-
First, by adjusting the speed of the machine,
Secondly, by controlling the supply of grain passing through the machine by
means of a slide below the hopper,
T
be the use of an index affixed to each stop cock of the gas burners.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Fordred in the Patent Office on the 28th June 1884.
JOHN FORDRED of Tottenham in the County of Middlesex Technical Chemist
"IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR TORREFYING GRAIN
AND OTHER SEEDS, PART OF WHICH APPARATUS IS APPLICABLE FOR OTHER
HEATING PURPOSES
»
The chief object of my Invention is to provide a simple and cheap means of
torrefying grain or seeds for various purposes, but more especially for use in
Breweries, Distilleries, and Vinegar Works.
Previously to the passing of the new Beer Act which came into operation on the
1st October 1880, malted barley was the chief material used in Breweries for the
production of Beer, and paid a heavy Excise duty, popularly known as the
Malt Tax, which tax had existed in some form or other in the United Kingdom
for more than 200 years.
The new Beer Act, 43 and 44 Vict: Cap. 20, introduced and passed by the
Government of Mr W. E. Gladstone, rendered it possible to use raw grain in
Breweries as a partial substitute for Malt, in the same manner as had heretofore
been permitted in Distilleries and Vinegar Works, but it was soon found that raw
grain (that is, grain unprepared in any way) was unsuited for the production of a
pleasant beer, and it became necessary to find some mode of treating the raw grain
in order to remove this objection.
Up to the present time, the best devised method of preparation appears to be
that of torrefying, or partially torrefying, the grain or cereal in the manner
described in the Specification of a Patent granted to me and bearing date the
8th day of November 1881 N° 4891.
In that Specification I refer to a modification of the ordinary Coffee Roasting
Apparatus, but I have since found by experiment that the form of apparatus to be
presently described is better adapted for the purpose of torrefaction, or partial
torrefaction, of any grain or seed, whether intended to be used for brewing, distilling,
vinegar making or other purpose.
The process of torrefaction being one of extreme delicacy, it is absolutely
necessary that it should be under perfect control, for which purpose it is requisite
to provide what may be called "an instrument of precision," in which each
individual grain can be uniformly acted on by the heat employed.-This has
hitherto been difficult when operating upon grain in bulk.
The best form of machine for this purpose appears to be one in which the
individual grains or seeds can be submitted for a short time to a high temperature
by contact with a heated metallic surface, or immersed in a highly heated
atmosphere, whilst at the same time they are kept in constant motion. This effect
I find is best produced by causing the grain to pass from end to end of a rotating
metal cylinder heated preferably by gas.
One necessary feature of such a cylinder is a means of easy access to its interior
for the purpose of removing any accumulation of grain caused by overheating or
otherwise.
In the accompanying Drawing, I have shewn in several views the newest and
most satisfactory form of my torrefying apparatus, a serious difficulty which I
encountered in my early experiments, viz, an intermittent or irregular delivery of
the grain from the rotating cylinder, having been removed.
In the accompanying Drawing; Fig: 1 is a longitudinal section of my improved
torrefying apparatus, consisting of a horizontal rotary cylinder enclosed in a jacketed
casing, and furnished with a gas heating apparatus.

page_text: Fig: 2 is an elevation of the left hand or feeding end, and Fig: 3 an elevation
of the right hand or delivery end of the apparatus.
Fig 4 is a sectional plan of the same taken in the line 1, 2 of Fig: 1, and
Fig: 5 is a cross section taken in the line 3. 4 of Fig: 1.
A A is a pair of standards connected together by longitudinal tie rods, and
carrying the fittings for the rotary torrefying cylinder B.
This cylinder which, as designed, has a heating surface 8 feet in length and
16 inches in diameter, is composed of sheets of thin metal b laid around a series of
rings or blades 61 61* projecting radially from a horizontal axle B', which blades
not only serve to carry the metal sheets forming the periphery of the cylinder, but
act as propellers of the grain submitted to the torrefying process.-The feeding end
of the cylinder is closed by a circular plate B2, which is cast with a boss at its
centre to receive the axle of the cylinder, and is dish-shaped on its inner faced,
and cored out on its periphery to form a passage into the cylinder for the grain to
be treated.
This end plate fits within a circular flange projecting from a casting A', which is
bolted to the standard A.
In the upper part of this casting is a neck c corresponding in cross section with
the cored out passage in the end plate B, and upon this neck is fitted a hopper C
for supplying the grain to the cylinder as the cylinder, in its rotation, brings the
supply passage of the plate B2 into coincidence with the neck c.
This neck is provided with a slide c¹ for regulating the supply of the grain from
the hopper C.
The delivery end of the cylinder B is open, and it projects through an annular
casting A2 bolted to the standard A* at the right hand end of the machine, and
overlies a delivery shoot D.-This open end of the cylinder I cover with a cap or
shield set up facing the end of the cylinder, and carried by the shute or other
convenient fixed portion of the apparatus.-This will ensure the delivery of the
torrefied grain into the shute.
The axle at the delivery end of the cylinder turns in a bearing carried by an
open bracket bolted to the standard A*.-At its other end this axle turns in a
bearing carried by a bracket bolted to the casting A¹.
At the feeding end of the cylinder, the radial blades are by preference set at an
angle, the pitch being some 12 or 14 inches, for the purpose of leading forward the
grain as it is delivered to the cylinder from the feeding end.
Each ring consists of six radial blades, which are so arranged that the blades of
each ring stand opposite the spaces of the next adjacent ring, as shewn in the cross
section, Fig: 5.
The blades are severally screwed into the axle B', and they are provided with
lock nuts for securing them in place when properly adjusted.
It will in general suffice to give to the first six or seven rings of blades an
inclination or pitch, the remainder being set with their flat sides in line with the
axle, a position which ensures a uniform rate of travel to the grain through the
cylinder.
I avail myself of a longitudinal row of these blades b* to secure in place the
sheets of metal b forming the periphery of the cylinder, and for this purpose, in
the line where the longitudinal lap of the metal sheets occurs, I provide the blades
with a broad end for the lapping sheet metal to bed upon, as shewn at Fig: 5*,
and I drill and tap the ends of this row of blades to receive screws 6², which pass
through holes in the lapped edges of the sheet metal, and entering the tapped holes,
secure the sheets firmly in place.
In this way I not only secure the longitudinal joining of the metal forming the
periphery of the cylinder, but provide a facile means of access to the interior of the
cylinder B for the purpose of clearing the same of any charred grains that may
adhere to the cylinder.
As the length of the cylinder will measure some 8 feet, several breadths of sheet
metal will be required to complete the cylinder; in applying these sheets, I ag

page_text: arrange the lap joints that they will present no obstruction to the travelling
grain.
The cylinder B is enclosed in a jacketed wrought iron cylindrical casing packed
with filamentary asbestos, or with silicate cotton, for the purpose of retaining the
heat generated by the burners to be presently described.
This casing is made in two parts D D¹, the part D being fixed to the castings A.¹
and A2, and the part D¹ being hinged to the standards A. A* for the purpose of
getting access to the cylinder, as indicated by dots at Fig: 2.
This casing, when closed, presents a longitudinal opening at bottom, to allow the
flame of the gas burners E E¹ to play upon and around the cylinder B.
The upper part of this casing is slotted longitudinally as at d, and it is fitted
with damper valves for the purpose of regulating the temperature within the
casing. When the casing is closed, the hinged portion D' is secured by hasps to
the fixed portion.
Underlying the bottom opening in the casing, and extending from end to end of
the machine, is a metal trough F, which is intended to receive the gas burners E E¹
and hold them to the required height below the rotary cylinder B, their distance
therefrom being made variable to suit the work in hand.
This metal trough slides in guides formed for it in a pair of forked plates F
bolted respectively to the standards A A*-Pivotted to lugs cast on the face of
these plates is a pair of bell crank levers f, the horizontal arms of which are
connected by metal straps f¹ to the underside of the trough.
The pendent arms of the bell crank levers are each cast with a forked extremity
to receive a nut f2, which is pivotted thereto to leave it free to rock in its
support.
Through these nuts passes a right and left handed screwed rod f³, which projects
through the plates F¹, and is fitted with collars near its ends to prevent it moving
endwise. One end of this rod projects through the standard A*, and is squared to
receive a hand wheel, by turning which the trough F may be adjusted vertically
to suit the requirements of the work in hand.
The construction of the gas burner used, which is somewhat peculiar, is best
illustrated in the detached sectional view Fig: 6, which represents the burner as
consisting of an iron tube e of say 5 inches in diameter, and of about feet
6 inches in length, provided with a longitudinal slot e¹ through its upper side, some
3 feet 9 inches in length and 2 inches wide.-Both ends of this tube are closed,
and its outer end, which constitutes a mixing chamber, is fitted with a gas jet e¹,
set concentrically in the end of the tube, and having a bore of some 7 of an inch
in diameter. Immediately below this jet, an opening e³ is made in the tube for the
admission of air thereto, and this opening is protected by a shield or wind guard e-
Thus the air and gas commingle and fill the mixing chamber preparatory to entering
the slotted portion of the tube.
The longitudinal slot e¹ is covered by a strip of iron wire gauze of say 40 meshes
to the inch for producing a lambent flame.-The gas cock carries a graduated dial e
for indicating, by the aid of a fixed pointer e, as the cock is turned, the rate of
supply of gas admitted to the burner.
This construction of burner ensures an equable and regular supply of the mixed
gases throughout the whole length of the slot, and the consequent maintenance of
any determined degree of heat.
The machine, it will be seen at Fig: 1, is fitted with two burners such as that
just described, set end to end in the adjustable trough F, each receiving its own f
supply of the mixed gases, which issuing through the wire gauze covering the
narrow longitudinal slot, together give, when ignited, a flame nearly equal in
length to the length of the cylinder B.
In operating with the above described apparatus upon barley, I give the cylinder
by preference 60 rotations per minute, which is the speed that ensures the most
efficient distribution of the grain in the cylinder and the delivery of the torrefied
grain therefrom.-The cylinder I supply with the grain at the rate of from 8 to 12

page_text: bushels per hour. This will ensure the exposure of each grain to the action of the
heat from two to four minutes, after which it is discharged from the cylinder onto
the shute in a properly torrefied state.
The rate of consumption of the gas per burner for maintaining an efficient heat,
will range between five and six cubic feet per minute.
I may remark that this novel construction of gas burner is applicable wherever
an adjustable and uniform temperature for heating an extended surface is
required.
A modification of the manner of securing the sheets b in place is shown in the
detached views Figs: 7 and 8, the latter being drawn on an enlarged scale.-In
these Figures, it will be seen that instead of employing the screws 62. for securing
the longitudinal lap, I use a clamping device consisting of two strips of angle
iron 63. rivetted to the overlapping edges of the plates forming the longitudinal
joint. These angle irons I draw together by means of bolts and nuts 6+, which by
their easy removal provide a ready access to the interior of the cylinder.
From the foregoing description it will be understood that I am enabled to
control the action of my improved torrefying apparatus by three distinct means,
namely:
(1) By varying the rate of feed to the rotating cylinder.
(2) By adjusting the speed of rotation of the cylinder.
(3) By regulating the amount of gas consumed by the burner.
When these several means of control are properly adjusted to suit the grain
under treatment, the apparatus may be run steadily for a series of hours with
little or no attention from the attendant, his duty merely being to reduce the gas
flame so soon as the full temperature desired is reached.
It should be stated that the proportions given above, relating to the feed of
grain, the speed of rotation of the cylinder, and the consumption of gas, relate to
the treatment of barley only, but they will be a fair index of the adjustment
required from the attendant to suit grain of greater or less size.
Having now set forth the nature of my Invention of "Improvements in the
construction of apparatus for torrefying grain and other seeds," and explained the
manner of carrying the same into effect, I wish it to be understood that under the
above in part recited Letters Patent I claim :-
First The arrangement of self-feeding and discharging torrefying apparatus
above described with reference to the drawing, whereby I am enabled to torrefy
grain of whatever kind with precision by one continuous or long sustained
operation.
Second-The means above described for facilitating access to the interior of the
torrefying cylinder for the purpose above set forth.
Third: The construction of gas burner substantially as above described for
affording an adjustable amount of heat for torrefying and other heating
purposes.
In witness whereof I the said John Fordred have hereunto set my hand and
seal the twenty eighth day of June in the year of our Lord One thousand eight
hundred and eighty four.
TATTN
BORDDED