IMPROVEMENTS IN GRINDING CORN AND OTHER SUBSTANCES
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HURWOOD, of Ipswich, in the County of Suffolk, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Seventh day of May
(One thousand eight hundred and fifty), in the thirteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George Hurwood, my exors, admors, and assigns, Her especial license, full
power, sole privilege and authority, that I, the said George Hurwood, my
exors, adñiors, and assigns, or such others as I, the said George Hurwood,
my exors, adñiors, or assigns, should at any time agree with, and no others,
from time to time and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, my Invention of
"IMPROVEMENTS IN GRINDING CORN AND OTHER SUBSTANCES;" in which said
Letters Patent is contained a proviso that I, the said George Hurwood,
should cause a particular description of the nature of my said Invention,
and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after
the date of the date in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.
.

page_text: the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked thereon,
that is to say :-
My Invention consists,-
Firstly, of making or constructing metal mills in such a manner that the
operation of grinding is facilitated, and also that the cutting parts may be,
when required, readily replaced.
Secondly, my Invention relates to the application of fans fixed upon the
grinding or revolving part of metal mills to facilitate and improve the operation
of grinding, by inducing a current of air to pass between the grinding surfaces.
Thirdly, my Invention consists of introducing air between the grinding
surfaces of mill stones to facilitate and improve the operation of grinding.
In order that my Invention may be fully understood, I will proceed to
describe the Drawings hereunto annexed, in the different Figures of which the
same letters are used to indicate the same parts wherever they occur.
Figure 1 is an elevation of a metal mill, fixed to the framing for carrying
the driving apparatus. Figure 2 is a plan, showing the cover of the same.
Figure 3 is a section of the mill. a, b, are cast-iron plates, the faces of which
are accurately turned to receive the rings or plates c, c, d, d, e, e; these are
shown more clearly in the plan Figure 4, and also by the single ring Figure 5.
These rings (which I shall subsequently fully describe) are secured to the cast-
iron plates a, b, by conical screws, sunk below the cutting parts. The plate b
is secured to the end of the spindle f, and made to revolve accurately with the
same. The spindle f works in a steel or brass bush, fitted in the centre of the
bottom plate of the case at i, which it accurately fits as it does also the brass
step. The step k is in two parts to embrace the onion end of the spindle,
and the outside is turned to fit the socket 7, and is prevented turning in the
same by a stay screw m; the socket is also prevented turning in the outer case
which it fits by a similar contrivance. A piu from the socket passes through
the regulating screw piece n, and is coupled to the same by the screw and
washer o, so that the screw piece may turn freely and independently of the
socket; and it is obvious that by turning the regulating screw n, the spindle
and plate b will be adjusted to the upper plate a, consequently the corn or
material ground will be regulated accordingly. The upper plate a is fitted to
the covering plate p, with a ball and socket joint, which is accurately turned
and prevents the passage of the air between these plates, but allows of their

page_text: being adjusted. The plate a is held up to the covering plate by the centre
bolt 2, that passes through a wrought-iron bridge piece r, fixed in the same
and hung up to a similar pieces in the covering plate. t, t, t, t, are four
adjusting screws to set the face of the upper plate, so that it corresponds
exactly with the plane of the face b, when it revolves; when set it is secured
in its place by the set nuts that cover them, the screws being sunk into the
plate a also prevent its turning. Figure 4, u, u, u, are three wrought-iron
fans fixed to the plate b, only one is seen in the section, Figure 3), which, as
they revolve, disperse and drive the air through the spout, and thereby induce
a current of air to pass down the eye-hole and between the grinding surfaces.
The feeding apparatus of the mill are of the ordinary description, and need
not be described. For metal mills of unusual size air may be employed with
advantage to facilitate the grinding, by forcing it through the eye-hole to the
grinding surfaces, in which case it will be necessary to close the top of the eye
to preserve the pressure of the air through the covering, of which an arrange-
ment is made for the air and feed pipes to pass; air may also be admitted to
the grinding surfaces of metal mills, by introducing the air between the plate a
and cover p. The grinding plates in this case are perforated to allow the air
to pass to the grinding surfaces, and the air must be prevented by a ring of
leather, and a rim or some other suitable contrivance from passing between the
cover and plate to the outlet. The grinding operation of metal mills may also
be facilitated by exhausting apparatus being applied to relieve the case of air.
The rings or cutting parts may be made in various ways and with different
materials, dependent in some measure upon the work to be performed, and
also the cost. These I will now describe. To make rings of wrought iron or
steel they are first forged to the shape or punched from plates, then made true
and of uniform thickness. This is best done by turning them; the screw holes
are also drilled to one uniform position (which it is necessary to attend to,
particularly as one object of my Invention is the providing the means that any
of the grinding parts may be readily removed when worn out and replaced by
others. The pitch or space of the teeth, and also the angle to which the teeth
are cut, depends upon the work to be performed, as do also the number of
rings employed in Figure 4. Three are shewn, which are sufficient for a mill
twelve inches diameter, for grinding corn or pulse for the feeding of cattle.
The drift or angle of the teeth of the rings is not uniform, but is encreased in
each ring from the centre; and my object in doing so is, that the teeth of each
ring shall so freely discharge their work as not to clog or impede the work of
those that precede it; and the same thing is observed and done, whether the
grinding surface be a plane, conical, or other shape. The teeth may be cut

page_text: by hand, but are more readily done by the usual machinery calculated for
After the
doing such work, which is well known and need not be described.
teeth are cut on the rings, if made of wrought iron, they are casehardened;
and if of steel, tempered in the usual manner and fixed to the plates by screws
(as before stated). Flat wrought-iron and steel rings or plates may also be
made by subjecting them when hot to a heavy blow or sudden pressure, as
may be done by the steam hammer or heavy fly press upon a steel die, cut to
give the proper form to the teeth. Whole plates may thus be formed, with
the different grades of teeth and drifts or angles on them. Rings or plates
thus made would of course require to be made true and hardened in a similar
manner as the plates before mentioned. I also make chilled cast-iron rings
and plates by running hot iron into iron moulds prepared to make them, of the
desired form and dimensions, and cut to give the requisite form and angle to
the teeth. These plates are applied and used in the same manner as those
made of wrought iron or steel. I also cast in iron, in suitable moulds, separate
blocks, with the teeth cast upon the edges. These are afterwards bored and
fitted together on a spindle to form cones or conical figures, as shewn,
Figure 5, x, y, z. Other figures may be formed in a similar manner if the
cutting parts are made in this way. The block or body which is necessary to
receive the rings or plates when made separate will not in such cases be
required. Plates (similar to that shewn in Figure 5) with the teeth cast upon
them are made in a similar manner, to be put together upon the body or
receiving plate of the mill, as the steel rings, whole plates, with the different
grades and angles of the teeth cast upon them, are also made in the same
manner. Figure 6 shows a section of a similar mill. Figure 7, plan of the
same. Figure 8, side view of the same. This mill is arranged to work
vertically.
I would remark, I do not confine myself to any particular position in fixing
these mills; (the same letters of reference, as far as they apply, are similar to
those described in Figure 3, and therefore need not be repeated. k is a steel
or brass ring, fitted to spindle. n is a collar enclosing the brass, which is
prevented turning as the spindle rotates by the screw s. This collar is screwed
internally and fitted to the case m, and it will be evident that if this collar is
turned, the grinding faces will be adjusted accordingly. o is a feeding roll
worked from the spindle f by the pullies v, w; the pullies a, a, are for
driving the mill. Figure 9 shows a plan of a conical mill upon the same
principle as that already described. Figure 10, an elevation of the same.
Figure 11, a section of the same. The cast-iron case a is truly bored out to
the proper angle to receive the rings forming the cutting parts b, c, d. These

page_text: are secured to the same by small screws from the outside of the case; one of
these screws is shewn at e. A cast-iron cone is fitted and secured to the
spindle f. 9 is the cone, which is accurately turned to receive the rings h, i, k.
A separate view of the cone, with the rings upon the same, is shewn at
Figure 12, and a single ring at Figure 13. The cones are adjusted to each
other for grinding by the arrangement shown at the delivering end of the mill.
The spindle has a collared end working against two steel washers, inclosed
by a screwed collar n, which is connected to the outside end plate of the cone
case m by an internal collar that is fixed to the cone case m, but screws freely
in the collar n, by which the surfaces of the cone are easily adjusted. u, one
of the fans. Figure 14 shows more clearly the three fans u, u, u, which are
made of wrought iron, and attached to the end of the revolving cone, and
work within the space between the cone and case. The use of the fans has
been already adverted to as applied to metal mills, and as the driving of the
mills may be by any of the means calculated and usually employed for such
purposes, it will be unnecessary to describe them.
I will now describe that part of my Invention that relates to the ventilating.
of millstones for grinding corn. Figure 1 shews a section of a pair of mill-
stones and case, as ordinarily used with my Invention attached. Figure 2
is a plan of the top cover. Figure 3 is a plan of the casting a fixed in the
eye of the stone. I am aware that several means have been applied to
ventilate millstones, all attended with more or less inconvenience and derange-
ment of the usual modes of working the stones.
My Invention consists of means of applying air to the grinding surfaces by
pumps or fans, or any of the usual method of producing a current of air
admitting of the usual mode of feeding and working the stones. Figure 1 is
a section of a pair of millstones; a is a casting fitted into and secured in the
eye of the running stone; 6 is a casting that drops into the place provided for
it in a; c is a bell-mouthed casting that is secured to b by eight screws
marked d (see Figure 2), and is secured to the wood covering of the stones
by screws, shewn at Figure 1; between the casting a, and the casting b, the
space is filled with hemp packing e, l, which is kept in its place by two rings
ff, secured to a by four screws g. 9, 9,9; the inside of the casting a, against
which the packing presses, is truly turned and fixed exactly concentric with
the motion of the stone, allowing the same to revolve without impediment, at
the same time stopping the passage of air. Figure 6 shews another arrange-
ment to effect the same object; in this case the packing is dispensed with,
and leather is used in its place, which is pressed against the surfaces of the
casting a; hoops or springs are used at r, v, to keep the leather close, and so
as to stop the passage of air. The air is to be introduced into the space

page_text: formed between the casting a and the eye of the stone by one or more pipes
(the number and size of which depends upon circumstances, each of which
pipes, or the main pipe leading to them is furnished with a cock or valve to
regulate the supply. These pipes may be fixed under the top cover of the
case or cover it, as shown in Figures 1 and 6. The Drawing shows two
pipes h h; i, i, are the regulating valves. The pipes are so fitted as to be easily
removed to allow of the stone being turned over when required to be dressed.
From the casting a I make a number of holes or appertures marked k, to the
face of the stone at an angle of about 45°, which gives an easy passage for
the air to the grinding surfaces of the stones in the right direction to cool the
meal and discharge the same as soon as ground. Figure 7 shows the face of
the runner stone with the holes or apertures marked k, which, as will be
perceived are led into the second furrow, and one opens into every bed (as the
division of the dress of the stones are technically termed). But I wish here
to remark, that I do not confine myself to the number of openings, or their
exact position, for these must depend upon circumstances; I am, however,
always careful the apertures shall not be so close to the eye as to risk the
chance of the air passing up the same instead of between the grinding surfaces
to the circumference of the stones. The case that encloses the stones is
ventilated by one or more pipes or openings, one is shown at b, Figure 7.
My methods of introducing air to the grinding surface from the bedstones
are shown by the following Figures:-Figure 8, section of bedstone, neck box,
pipes, &c. Figure 9, plan of under side of neck box. Figure 10, section of
neck box. Figure 11, plan of face of stone neck box and pipes. Figure 12,
section of bed stone, showing holes made at an angle from the eye into the
neck box. The neck box marked a is made hollow to receive the air, which
is supplied by any of the ordinary means through the main pipes b, b, which
(as in the former case) are supplied with cocks and valves to regulate the
quantity; at the top of the box a number of small pipes or tubes are fixed,
marked c, c, &c. which are let into the stone and fixed below the grinding
surfaces; these pipes, as will be perceived, are led into the second furrow in
every bed of the stone. I may here, however, remark, that I do not confine
myself to the number of pipes employed, or the exact position to which the
air is led before it is discharged, as both these must be dependent upon
circumstances: the ends of the pipes are cut in a sloping direction, and the
ends slightly compressed to spread the current of air which is forced through
them. Figure 12 shows a section of a bedstone, with another method of
introducing air to the grinding surface; a is a similar neck box, as before
described ; from the eye or chamber of the box a number of holes or aper-

page_text: tures are made at an angle to lead to the face of the stone k, k, through which
the air is supplied to the grinding surfaces.
Having described in the best manner I am able the nature and operation
of my Invention, I would have it understood that I do not confine myself to
the arrangements or the precise details shewn so long as the peculiar features
of my Invention are retained. What I claim is,―
Firstly, the mode of preparing the parts or bodies of metal mills to fit them
to receive the cutting or grinding parts, that when required, such parts may
be readily removed and replaced.
Secondly, the making the cutting parts in a series of plates or rings to be
put together when used either for planes, cones, or other figures.
Thirdly, the forming of the teeth of the cutting parts by stamping or
pressing the metal when hot upon dies.
Fourthly, the making the plates or rings forming the cutting parts by casting
iron upon chills.
Fifthly, the making the cutting parts in one piece with a series of teeth,
each so radiated and divided as to present a similar face to that presented
by putting together a series of separato rings (as shewn, Figure 4), either by
casting iron upon chills, or stamping iron upon dies.
Sixthly, the making of the case and plates with a ball and socket joint, and
adjusting screws for metal mills.
Seventhly, the application of fans to be fixed upon the revolving part within
the case of metal mills.
Eighthly, the causing of currents of air to pass the grinding surfaces of
metal mills, either by exhaustion or pressure.
Ninthly, the introduction of air between the grinding surfaces of millstones
by apertures made at an angle to the face of the stone from within the eye
bole of the runner stone.
Tenthly, the introduction of air between the grinding surfaces of millstones
from the bedstone, by making the neck box hollow to admit of the air being
forced through it, and fixing conducting pipes to the same, to convey the air to
the place required.
Eleventhly, the introduction of air between the grinding surfaces of mill-
stones, by apertures made at an angle to the face of the stone from within
the eye-hole of the bedstone.
In witness whereof, the said George Hurwood, have hereunto set my
hand and seal, this Sixth day of November, in the year of our Lord
One thousand eight hundred and fifty.
GEORGE (L.S.) HURWOOD.

page_text: AND BE IT REMEMBERED, that on the Sixth day of November, in the
year of our Lord 1850, the aforesaid George Hurwood came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that
purpose.
Enrolled the Sixth day of November, in the year of our Lord One
thousand eight hundred and fifty.