IMPROVEMENTS IN GRINDING WHEAT AND OTHER SUBSTANCES, AND IN THE TREATMENT AND PREPARATION OF SUCH SUBSTANCES AND THE PRODUCTS THEREOF
Year: 1852

page_text: LETTERS PATENT to John Currie, of Glasgow, in the County of
Lanark, North Britain, Miller, for the Invention of "IMPROVEMENTS
IN GRINDING WHEAT AND OTHER SUBSTANCES, AND IN THE TREATMENT
AND PREPARATION OF SUCH SUBSTANCES AND THE PRODUCTS THEREOF."
Sealed the 15th December 1852, and dated the 21st October 1852.
PROVISIONAL SPECIFICATION left by the said John Currie at
the Office of the Commissioners of Patents, with his Petition, on
the 21st October 1852.
I, JOHN CURRIE, of Glasgow, in the County of Lanark, North
Britain, Miller, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN GRINDING WHEAT AND OTHER SUBSTANCES, AND IN THE
TREATMENT AND PREPARATION OF SUCH SUBSTANCES AND THE PRODUCTS
THEREOF," to be as follows:-
This Invention relates to the manufacture and production of flour
from the raw grain, in the grinding the same, and in the dressing the
flour. In the process of grinding the upper millstone is stationary,
and is supported in a metal hoop carried by suitable brackets, whilst
the lower one rotates beneath it. The grain is supplied to a suitable
hopper or receiver placed above the eyo of the upper stone, and

page_text: communicating therewith at its bottom by an expanding chamber
surrounding the eye of the stone. Into one side of this chamber cold
air is blown amongst the grain as it falls from the hopper, so as to
mingle with it, and pass along with it through or between the stones to
keep the grain and grinding surfaces cool, aiding the grinding action,
and improving the quality of the flour. A central plate of metal covers
the eye of the lower stone, having a small passage through it for the
exit of a current of air from the eye of the upper stone. This air
passes down through the lower eye, and envelopes the lower revolving
surface and the base plate of the casing. Hence the air passes into
the annular space between the periphery of the lower stone and the
interior of the fixed case surrounding it. It fills this annular space,
and rising upwards it meets the flour and heated air emerging from
the grinding surfaces above. The two currents then pass up together
inside a light wooden case surrounding the upper stone, rushing against
a ring of wire gauze, which allows the air to pass through, but stops
any partially crushed grain. The grain and air may be mingled
together in one, two, or more supply pipes, in such manner that both
the grain and cool air may enter between the stones at the very point
where the grinding action commences. By preference two feed pipes
are used, being made to diverge downwards after the manner of a forked
branch from the narrow bottom discharge of the hopper, the revolving
feed spindle being passed up from the main spindle through a joint hole
in the fork, and the main feed pipe receiving the grain from the hopper.
After diverging at an angle outwards until they reach the surface of
the upper fixed stone, the two feed pipes pass vertically through a pair
of holes made directly through the upper stone, and set diametrically
one on each side the eye of the stone. An annular portion of the
under surface of this stone, extending far enough to reach the feed
apertures opening through it, is bevilled slightly upwards from the
outer side of these holes towards the eye, so as to leave a narrow space
between the two stones at this part for the free entry of the grain and
air, precluding the chance of the commencement of the grinding action
before the air has fully reached the acting surfaces. The cyc of the
upper fixed stone between the two teed pipes is covered over with a

page_text: metal or other disc, passed over the feed spindle, and capable of adjust-
ment at any required height above the eye as a valve. The grinding
surface of the lower running stone is perfectly flat throughout, and its.
eye at the grinding level is covered over by a metal plate with a central
aperture round the feed spindle for the passage through of a portion of
the air. In this way part of the air may be discharged at the eye,
of the upper stone, and part drawn through the eye of the runner
beneath, whilst the main body of the air goes along with the grain, and
is discharged with the ground material at the periphery of the stones..
By this contrivance the entire surface of both stones is kept encircled.
by a constantly changing air bath or current; for the air escaping at
the eye of the upper stone is directed by the valve disc over its entire,
surface, whilst that from the bottom of the lower eye passes over the
whole bottom surface of the runner, between it and a bottom base plate..
This has a ventilating effect, for on the upper edge of the iron casing
which surrounds the lower running stone and supports the upper fixed
stone, is placed an annular disc of wire covering over the annular
space left between the periphery of the stones and the interior of of the
casing. This wire cloth stands a short distance above the level of the
grinding surfaces, and from its periphery a light wooden casing springs.
upwards, surrounding the upper stone, and bevilled inwards at some
distance above the stone's surface. Thus there is a current of cold air,
passing from the running eye up outside the stone, and inside the
casing. There it meets the heated current from the grinding surfaces
at right angles, and breaking this heated current, whatever ground
material is held in suspension falls back within the bottom casing,.
whilst the heated air passes off through the wire cloth, again meeting
at right angles with a cool current from the upper side of the top stone,
which, in conjunction with the bevilled top of the upper case, still further.
separates the suspended flour, and aids the ventilation.
The same
arrangement is also applicable when the upper stone is the runner.
Another modification of the stones consists of the combination of three
or more separate stones, instead of two as hitherto used. In this plan
the central stone is the runner, the upper and lower ones being fixed,
so that the grinding is performed both between the under surface of the

page_text: "'
upper stone, and the upper surface of the central runner, and between
the under surface of the latter and the upper surface of the bottom
fixed stone. The grain and air may, or may not, be supplied to these
stones in the manner detailed in reference to the first described plan of
a pair of stones, each grinding surface being separately supplied, and
the ventilation being carried on in a similar manner. This contrivance
is not confined to three stones, but may be extended by adding other
runners and fixed stones one above the other in a column. The royne
for connecting the spindle to the runner is formed on the "balance
principle; that is, the connection is by means of a spherical or ball
joint, to prevent derangement from the spindle and runner being out
of truth. In cases where the stones are on the floor, the spindle passes
down from above, and enters through the eye of the upper stone, the
attachment with the lower runner being by a universal balance joint.
Instead of blowing cold air into the eye, the warm air may be sucked
out of the outside casing, and instead of using the heated air of the
mill, external cold air may be brought in by a pipe. In dressing the
flour, the ordinary dressing machine is increased in efficiency by adding
to it a peculiar feeder, placed near the head or supply end of the
machine. This feeder is composed of an inclined cylinder of strong
wire-work, having within it a revolving spindle carrying a series of
blades, and inclosed in a fixed external cylinder, having an annular
space between the two. As the ground material is fed into the head.
of the feeder, the flour is forced through the wire-work into the
outer cylinder, and is thence passed into the ordinary dressing cylinder,
whilst the grains which have originally escaped grinding pass out at
the bottom inclined end of the wire cylinder where they are collected
for regrinding, instead of being mixed with the bran. In this way the
flour is sifted of all matters likely to injure the dressing cloth. Or the
secondary cylinder may be placed within the dressing cylinder which in
this case is conical, its widest end being at the feeding mouth. It
revolves on the main dressing shaft, and has stationary brushes within
it. The flour is fed in it between two of the brushes on the upper side,
and is forced through the wire into the dressing machine by the brush
action and the internal air current, whilst the rough matters fall out

page_text: at the bottom side. Flour may also be dressed by the reciprocating
motion of a silk diaphragm. The flour is fed into the upper or ridge
side of a species of triangular chamber, the bottom or base of the
triangle of which is formed of a reciprocating silk diaphragm, through
which the fine flour passes when in action. In this way the entire
surface of the silk is put to use at one time, and any pressure of air
may be obtained for forcing the fine flour through. The same feeding
apparatus is also adopted for the French dressing machine as fitted
with silk dressing cloth, the ends of the dresser being quite closed up.
The air and ground material are supplied together by the feeder, so
that the ground material enters in a well opened and loose state.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Currie in the Great Seal Patent Office on
the 20th April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN CURRIE, of Glasgow, in the County of Lanark, North Britain,
Miller, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of October, in the
year of our Lord One thousand eight hundred and fifty-two, in the
sixteenth year of Her reign, did, for Herself, Ier heirs and succes-
sors, give and grant unto me, the said John Currie, Her special
licence that I, the said John Currie, my executors, administrators, and
assigns, or such others as I, the said John Curric, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVENIENTS
IN GRINDING WHEAT AND OTHER SUBSTANCES, AND IN THE TREATMENT AND
PREPARATION OF SUCH SUBSTANCES AND THE PRODUCTS THEREOF," upon the
condition (amongst others) that I, the said John Curric, by an instru-
ment in writing under my hand and seal, should particularly describe

page_text: and ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
☐ NOW KNOW YE, that I, the said John Currie, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawings hereunto
attached, and to the letters and figures marked thereon (that is to say):
My said Invention relates,-
First, to various arrangements of machinery, apparatus, or means,
appertaining to mill stones and their gearing and connections, for
economising the cost of grinding, and for the production of a superior
article at a quick rate.
Second, to modifications of the dressing machine, whereby flour may
be dressed at a more speedy rate than hitherto.
Figure I. on my Sheet of Drawings is a transverse vertical section
of one modification of my improved mill stones as mounted for
grinding wheat. In this case the grain to be ground is supplied by
the valved feed pipe A, to the hopper D, standing above the eye of the
fixed upper stone C, and communicating therewith at its bottom by an
expanding chamber D, surrounding and fitting into the eye E, of the
stone. Into one side of this chamber D, cold air is blown down by the
pipe F, amongst the grain as it falls from the hopper, so that the grain
and air are well commingled, and pass down together to the grinding
surfaces as indicated by the arrows. This application of the air has the
effect of keeping the grain and grinding surfaces cool, aiding the
grinding action, and improving the quality of the flour. A central
plate of metal G, covers the eye H, of the lower stone or runner I, a
central space being left in it for the passage through of a current of air
from the eye of the upper stone. It is by this central annular space
that air passes down through the lower eye, and envelopes the lower
revolving surface of the stone, as well as the base plate J, of the
easing. From this point the air passes into the annular space K,
between the periphery of the lower stone and the interior of the

page_text: fixed annular case L, surrounding it. The air thus fills this annular
space, and rising upwards it nicets the flour and heated air emerging
from the grinding surfaces at M, above. The two currents then pass
up together inside a light wooden case N, surrounding the upper stone,
and they thus rush against a ring of wire gauze O, set in the top of the
casing, the air passing through this gauze, whilst any partially crushed
grain is detained, and falls back into the casing. The upper stone is
retained in position by the brackets P, having adjusting bolts at Q, upon
the lower casing; and a space is left at R, hetween the upper surface
of the upper stone and its cover, so that air may find its way therein to
assist in keeping the whole cool. The runner is driven by the spindle
S, which has a conical top entered into a cross, piece or ryne T, re-
cessed into the lower side of the stone. It is from the top of this
spindle that the feed spindle U, passes up to carry the feed cup or disc
V, by which the grain is fed in the ordinary manner, down the central
pipe W, the requisite adjustment being effected by the handle X.
Figure 2, is a vertical section of a second modification of my mill
stones and connections, arranged so that the cooling air may be
mingled with the grain by two or more supply pipes. in such a
manner that both the grain and air may enter between the stones
at the very point where the grinding action commences. For this
purpose I prefer to use two or more feed pipes A, diverging down-
wards like a forked branch of a tree from the narrow bottom dis-
charge opening of the hopper B, the revolving feed spindle C, being
passed up from the main spindle D, through a joint hole in the
fork into the main feed pipe E, receiving the grain from the hopper
after diverging downwards, until they reach the upper surface of the
fixed stone F. The two feed pipes pass vertically through a pair
of holes G, made directly through the upper stone, and set diametri-
cally one on each side of the eye of the stone. An annular portion
of the under surface of this stone, extending far enough to reach the
feed apertures opening through it, is bevilled slightly upwards front
the outer side of these holes towards the eye, as at H, so as to leave
a narrow space between the two stones at this part for the free entry of
the grain and air, and precluding the chance of the commencement

page_text: of the grinding action before the air has fully reached the acting sur-
faces. The eye of the upper feed stone, between the two feed pipes is
covered over with a metal or other disc I, passed over the feed spindle,
and capable of adjustment at any required height abovo the eye as a
valve. The grinding surface of the lower running stone J, is perfectly
flat throughout; and its eye K, at the grinding level is covered over by
a metal plate L, with a central aperture round the feed spindle C, for
the passage through of a portion of the air. In this way part of the
air may be discharged at the eye of the upper stone, and part down
through the eye of the runner beneath, whilst the main body of the air
goes along with the grain, and is discharged with the ground material
at the pripery of the stones. By this contrivance the entire surface
of both stones is kept encircled by a constantly changing air bath or
current; for the air escaping at the eye of the upper stone is directed
by the valve discover its entire surface, whilst that from the bottom of
the lower eye passes over the wholo bottom surface of the runner,
between it and the bottom case plate M. This has a ventilating
effect, for on the upper edge of the iron casing N, which surrounds
the lower running stone and supports the upper fixed stone, is placed
an annular disc of wire cloth O, covering over the annular space left
between the periphery of the stones and the interior of the casing. This
wire cloth stands a short distance above the level of the grinding sur-
faces, and from its periphery a light wooden casing P, springs upwards,
surrounding the upper stone, and bevilled inwards at Q. at some distance
above the stones surface. Thus there is a current of cold air passing
'from the running eye up outside the stone and inside the casing; there
it meets the heated current from the grinding surfaces at right angles,
and breaking this heated current, whatever ground material is held in
suspension falls back within the bottom casing, whilst the heated air
passes off through the wire cloth, again meeting at right angles with a
cool current from the upper side of the top stone, which, in con-
junction with the bevilled top of the upper case, still further separates
the suspended flour, and aids the ventilation. The same arrangement
is also applicable when the upper stone is the runner.
Another modification of my mill stones relates to the combination

page_text: of three or more separate stones instead of two as hitherto used. In
this plan, which is represented in Figure 3, the central stone A, is
the runner; the upper and lower ones B, C, being fixed so that the
grinding is performed both between the under surface of the upper
stone at D, and the upper surface of the central runner, and between
the under surface of the latter, and the upper surface of the bottom
fixed stone at E. The grain and air may or may not be supplied
to these stones in the manner I have previously detailed. In the
present instance, as I have arranged the parts in my Drawing;
the grain is fed through the pipe F, into the hopper G, through the
adjustable feed passage into the pipe H; hence the supply for the
upper grinding surfaces passes out by the inclined lateral opening I,
into the hollow space J, in the upper stone, forming the lower part of
the eye thereof. Here it falls on to the disc K, and is directed to the
grinding surfaces as pointed out by the arrows. The supply of grain
for the lower or secondary grinding action passes out at the bottom of
the pipe H, into the eye of the runner A, and thence proceeds to the
grinding surface as indicated by the arrows. The upper stone is
supported by side brackets as I have already described, these brackets
being carried on the lower annular casing L, bolted down to the floor
M. The bottom stone is sunk in a casing N, recessed into the floor or
platform, being steadied laterally by an annular piece of metal level
with the floor, whilst it rests on adjusting bolts O beneath. The spindle
P, driven by gearing from below, rests in an adjustable balance foot
step Q; it is fitted to the runner by a ryne made on what I term the
"balance" principle. The top of the spindle is spherically shaped as at
R, being passed through the collar disc S, and fitted into a spherical
recess in the under side of the ryne T, connected to the stone A. In
this way, as the connection between the spindle and the stone is entirely
formed by this ball and socket, no derangement can arise from the
spindle and runner getting out of truth. By this triple stone arrango-
ment I am enabled to obtain a large extent of grinding surface in a
small compass, and with a limited extent of gearing. This contrivance
is not confined to three stones, but may be extended by adding other
runcers and fixed stones one above the other in a column.

page_text: Figure 4, on my Sheet of Drawings is a transverse vertical section
of another form and arrangement of my improved millstones. In this
arrangement the lower stone A, is the runner or revolver; it is
surrounded by a cast-iron casing composed of the base plate D, and
the annular piece C, bolted down to the base. The upper stone D, is
the fixed stone; it is sustained by the bracket pieces E, supported on the
lower casing, and having adjusting bolts at F. The upper stone has a
wood casing G, combined with the bottom case, to form a complete
box to cover up the annular space outside the stones. In this case the
runner A, is driven from above by the main spindle H, which passes
down through the centre of the adjustable tubes I, of the feed hopper J,
and terminates in a convex foot K. This foot rests in a concavity in the
top of the disc piece L, which has formed upon the centre of its lower
surface a spherical journal or step piece M, resting in a brass N, car-
ried in the top of the adjustable block O. The bottom of the spindle
'has a transverse piece P, forged upon it, and arranged to gear into
slots in a projection standing up from the upper face of the disc piece
E, so that the spindle cannot revolve without carrying this disc with it.
This disc L, is secured vertically to the upper disc Q, of the ryne, by
bolts passing up from below; and it is adjustable laterally by sot
screws R, passed through the vertical arms S, of the ryne, and bearing
against the disc's periphery. These vertical arms terminate in an
annular piece T, from which projections U, pass into corresponding
internal slots. In the lower end of the eye of the stone a large box
piece V, is firmly wedged into the eye of the runner from above,
covering up the whole of the ryne apparatus; and this box piece has
an upper collar upon it, through which side bolts W, pass. These bolts
pass as well through the feed cup piece X, and finally bear upon the
spindle which passes through the cup piece, and into the box. By this
arrangement the full benefit of the universal joint or "balance"
connection is obtained, as the bolts W, and R, admit of exact lateral
adjustment, and the stones will work accurately even if they should get
out of truth with the spindle. The bottom block O, rests on the top of
the screw bolt Y, which works in a brass nut Z, the latter carrying a
notched disc a, for turning by the adjusting lever b. The forked end of

page_text: this lever embraces and is jointed to a loose ring c, by a pin on each
side, so that the lever may be engaged and disengaged from the notches
in the disc a, at pleasure. In this way, as the disc a, is fast to the
brass Z, the attendant, by urging round the lever when engaged in one
of the notches, can screw up the spindle Y, and thus raise the block O,
as may be required. This movement resembles that of a ratchet drill!
wherein a few short strokes and a succession of engagements with the
disc notches gives a considerable power of traverse. The block O, is
capable of being fixed by a set screw d, passed through the projecting
bottom collar e, of the base plate. The grain is fed into the hopper J,
by the pipe f; the communication from the bottom of the hopper into
the wide eye g, of the upper stone being through the lateral openings h,
whence the grain falls upon the cup piece X. The feed is adjustable
at i, in the usual manner, by raising or lowering the hopper and' its
discharge pipe. The lower edge of the wide eye of the upper stone is
well rounded off at j, and the grinding surface is slightly bevilled off
towards the periphery of the stone, to leave a space for the entry of the
grain and air, if an air current is used. In the present instance, a
current is supposed to be obtained by exhaustion from the casing
through the pipe k. When necessary the grain feed may be entirely
shut off by lowering the external pipel, over the holes h.
Figure 5, represents my improved arrangement of dressing machine
for dressing the ground wheat. Under this head, my Invention
consists in adding to the ordinary dressing machine, of which a' portion
is shown at A, a peculiar arrangement of feeder B. This feeder,
which is placed at or near the head or supply end of the machine,
is composed of an inclined cylinder C, of strong wire work, having
within it a revolving spindle D, carrying a series of blades or vanes E,
the whole being inclosed in a fixed external cylinder F, an annular
space being left between the two cylinders. As the ground material
is feed into the head of the feeder, the flour is forced through the
wire work into the outer cylinder, and is thence passed into the
ordinary dressing cylinder, whilst the grains which have originally
escaped grinding pass out at the bottom inclined end of the wire
cylinder at G, where they are collected for re-grinding, instead of

page_text: being mixed with the bran. In this way the flour is sifted of all
matters likely to injure the dressing cloth. Or the secondary cylinder
may be placed within the dressing cylinder, which in this case is
conical, its widest end being at the feeding mouth. It revolves on the
main dressing shaft, and has stationary brushes within it. The flour is
fed into it between two of the brushes on the upper side, and is forced
through the wire into the dressing machine by the brush action and the
internal air current, whilst the rough matters fall out at the bottom
side.
Having now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be used or
carried into effect, I may observe in conclusion that I do not confine or
restrict myself to the precise details or arrangements which I have had
occasion to describe or refer to, as many variations may be made there-
from, without deviating from the principles or main features of my
Invention. But what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part
recited Letters Patent, is-
First, the general arrangements of machinery, apparatus, or means
for grinding wheat and dressing flour, as herein-before described.
Second, the system or mode of working millstones wherein the grain
and cool air are supplied together to the grinding surfaces.
Third, the arrangement and construction of grinding apparatus,
wherein separate currents of air are passed through the eye of the
runner, and between the grinding surfaces.
Fourth, the system or mode of arranging millstones, wherein the
whole of the external and internal surfaces are surrounded by an air
stratum or bath.
Fifth, the application and use of wire cloth or other permeable
diaphragm on the top of the stone casing, for the separation from
the air of the matter held in suspension therein.
Sixth, the system or mode of supplying cool air to the grinding sur-
faces through apertures in the body of the fixed stone, as described in
reference to Figure 2, on my Sheet of Drawings.
Seventh, the application and use of an adjustable cover or valve on

page_text: the eye of the fixed stone, as delineated in Figure 2, on my Sheet of
Drawings, for the adjustment of the air pressure.
Eighth, the system or mode of working millstones, wherein the
heated current issuing from the grinding surfaces at the peripheries of
the stones is acted upon by a separate current of cold air.
Ninth, the system or mode of arranging millstones, wherein both
sides of the runner are employed in grinding.
Tenth, the arrangement and construction of millstones and their
gearing, wherein a central runner has a fixed stone above and below.
Eleventh, the system or mode of connecting the spindle to the
runner, wherein the runner is supported on a detached central ball
pivot.
Twelfth, the system or mode of arranging millstones, wherein the
balance ball pivot forms the supporting bearing for the stone.
Thirteenth, the system or mode of working millstones by a spindle
disconnected from the bearing balance pivot of the runner.
Fourteenth, the system or mode of separating the unground matters
from the flour, prior to the entry of the latter into the dressing machine
by means of a primary clearing apparatus.
Fifteenth, the application and use of a permeable cylinder with
revolving vanes or brushes therein, for giving a primary cleaning action
to the ground material before entering the dressing machine.
In witness whereof, I, the said John Currie, have hereunto set my
hand and seal, this Nineteenth day of April, in the year of our
Lord Oue thousand eight hundred and fifty-three..