IMPROVEMENTS IN MILLS FOR GRINDING OR CRUSHING
Year: 1868

page_text: LETTERS PATENT to Walkden Thompson and Thomas Stather, of
the Borough of Kingston-upon-Hull, Engineers, for the Invention
of "IMPROVEMENTS IN MILLS FOR GRINDING OR CRUSHING."
Sealed the 14th July 1868, and dated the 22nd January 1868.
PROVISIONAL SPECIFICATION left by the said Walkden Thompson
and Thomas Stather at the Office of the Commissioners of Patents,
with their Petition, on the 22nd January 1868.
We, WALKDEN THOMPSON and THOMAS STATHER, of the Borough of
Kingston-upon-Hull, Engineers, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MILLS FOR GRINDING OR CRUSHING,"
to be as follows:-
Our Invention relates to mills in which the material to be operated
upon is, supplied to a circular casing or drum in which beaters are fitted,
the beaters having a rapid rotary motion imparted to them so as to grind
or crush the material against the inside of the drum or against a re-
volving ring in the drum, the drum or the ring being serrated or plain
internally.
We make the discharge aperture at the lower part of the drum instead
of at the upper, and we cover the aperture with wire screens or per-
forated plates, so that by having screens or plates with different sized
meshes or perforations the grinding or crushing may be regulated to any
required degree of fineness or roughness; for grinding bark, for instance,

page_text: we employ plates with perforations of, say, 14 inches and less, as
required, while for grinding a material very fine wire screens with, say,
40 meshes or more to the inchi may be employed.
For grinding grain the spindle or shaft of the beaters in the drum
passes through the lower part of the feed hopper, and is made with a
screw to feed the grain into the drum or with pins to agitate the grain
and make it enter the drum in a regular manner. At the side of the
drum opposite the hopper is a spout' to admit a current of air to keep the
mill cool; and this spout may be used when required to feed larger
substances, such as bones, into the drum. For very light substances,
such as myrobalans, coal dust, charcoal, and glass, we make the delivery
aperture at the upper part of the drum as formerly, and we employ an
inclined screen fitted in a box or case; all the crushed or ground
material ejected from the drum falls on this screen; all the fine parts
pass through the screen, while those not sufficiently ground run down
the incline of the screen back into the drum to be submitted again to the
action of the beaters.
SPECIFICATION in pursuance of the conditions of the Letters Patents,
filed by the said Walkden Thompson and Thomas Stather in the
Great Seal Patent Office on the 20th July 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WALKDEN
THOMPSON and THOMAS STATHER, of the Borough of Kingston-upon-
Hull, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of January, in the
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs, and successors,
give and grant unto us, the said Walkden Thompson and Thomas
Stather, Her special licence that we, the said Walkden Thompson and
Thomas Stather, our executors, administrators, and assigns, or such
others as we, the said Walkden Thompson and Thomas Stather,, our
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,

page_text: the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN MILLS FOR GRINDING OR CRUSHING," upon the condition (amongst others)
that we, the said Walkden Thompson and Thomas Stather, or one of us,
our executors, or administrators, by an instrument in writing under our,
or one of our or their, or one of their hands and seals, should particularly
describe 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 we, the said Walkden Thompson and Thomas
Stather, do hereby declare the nature of our said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement thereof, reference.
being had to the accompanying Drawings, and to the figures and letters
marked thereon, that is to say:-
Our Invention relates to mills in which the material to be operated
upon is supplied to a circular casing or drum in which beaters are fitted,
the beaters having a rapid rotary motion imparted to them, so as to
grind or crush the material against the inside of the drum or against a
revolving ring in the drum, the drum or the ring being serrated or plain
internally.
We make the discharge aperture at the lower part of the drum instead
of at the upper, and we cover the aperture with wire screens or per-
forated plates, so that by having screens or plates with different sized
meshes or perforations the grinding or crushing may be regulated to any
required degree of fineness or roughness; for grinding bark, for instance,
we employ plates with perforations of, say, 1½ inches and less, as
required, while for grinding a material very fine wire screens with, say,
40 meshes or more to the inch may be employed.
For grinding grain the spindle or shaft of the beaters in the drum
passes through the lower part of the feed hopper, and is made with a
screw to feed the grain into the drum, or with pins to agitate the grain
and make it enter the drum in a regular manner. At the side of the
drum opposite the hopper is a spout to admit a current of air to keep the
mill cool, and this spout may be used when required to feed larger
substances, such as bones, into the drum.
Figures 1 and 2 of the accompanying Drawings are vertical sections.
taken at right angles to each other of a mill constructed according to

page_text: our Invention: a, a, is the circular casing or drum to which the
material (say grain) to be ground or crushed is supplied; the inner
periphery of this casing is serrated. b, b, are beaters (not shown in
Figure 1) mounted on a shaft c, to which rapid rotary motion is imparted
by a belt passed round the drum d or otherwise; e is the supply or feed
hopper, through the lower part of which the shaft c passes; the shaft c
is provided with pins as shown for the purpose of agitating the grain
and thereby cause it to enter the drum a in a regular manner; the outlet
of the hopper e can be regulated as shown by a slide.f moved by a
threaded rod g. h is a spout or second hopper, which admits a current
of air to the drum a; this spout h may be used as the feed hopper in
place of the hopper e, when it is required to feed larger substances, such
as bones, to the drum. i, i, are discharge apertures, which are placed at
the lower part of the drum a (one at each side) instead of at the upper
part, as has been usual with this description of mill; we consider it
important to have the discharge at the lower part as shown; we cover
these apertures i, i, with wire screens or perforated plates, and by having
screens or plates with different sized meshes or perforations, we can
regulate the grinding to any degree of fineness. The screens or plates
are carried in frames k, which are held in place by screws .
Figures 3 and 4 represent a mill similar to that shown in Figures 1
and 2, but with only one discharge aperture and one hopper. Some-
times we make the drum a in two parts, as represented in Figures 5 and
6, and bolt them together as shown. We find this mode of construction
convenient when it is required to take the mill or drum to pieces. For
very light substances, such as myrobalans, coal dust, charcoal, and glass
we make the delivery aperture at the upper part of the drum as formerly,
and we employ an inclined screen fitted in a box or case; all the
crushed or ground material ejected from the drum falls on this screen;
all the fine parts pass through the screen, while those not sufficiently
ground run down the incline of the screen back into the drum to be
submitted again to the action of the beaters. This construction of mill
a is the
is represented in section in Figure 7, and in plan in Figure 8.
drum; b, the shaft carrying the beaters; c, the feed hopper; d, the feed
or inlet aperture; and e, the delivery aperture; fis an inclined screen,
fitted in a box or case g. The material ejected by the delivery aperture e
falls upon the screen f; that which is sufficiently reduced passes through
while the remainder runs down the screen and re-enters the
drum a by the inlet aperture d.
the screen,

page_text: When the mills are intended to grind materials which are liable to
get warm we form a number of small holes, as shown at x, x, in
Figures 4 and 7, round the shaft which carries the beaters. In operating
upon substances which are too large to be fed into the circular casing
they may be previously partly reduced or broken by causing them to
pass between a pair of rotating crackers or grooved rollers before they
enter the circular casing; these crackers would be placed above the
hopper for feeding the circular casing, and would be driven by any
convenient gearing or power.
And having now described the nature of our said Invention, and in
what manner the same is to be performed, we declare that we claim as
our "Improvements in Mills for Grinding or Crushing,"
First. In combination with a circular casing or drum and rotating
beaters we claim the construction of one or more discharge apertures at
the lower part of the drum, such apertures being covered with wire
screens or perforated plates, substantially as herein-before described and
represented in Figures 1 to 6 of the annexed Drawings.
Second. In combination with a circular casing or drum, rotating
beaters, and a feed hopper wo claim carrying the shaft of the beaters
through the lower part of the hopper, and providing such shaft with a
screw or pins, substantially as herein-before described and represented
in Figure 1 of the annexed Drawings.
Third. In combination with a circular casing or drum and rotating
beaters we claim the employment of an inclined screen so placed as to
return to the drums the material which has not been sufficiently reduced,
substantially as herein-before described and represented in Figures 7
and 8 of the annexed Drawings.
In witness whereof, we, the said Walkden Thompson & Thomas
Stather, Engineers, have hereunto set our hands and seals, this
the 16th day of July, in the year of our Lord One thousand
eight hundred and sixty-eight.