Improvements in the Construction of Mills for Grinding Flint, Stone, Bone, Glaze, and other like Substances.
Year: 1890

page_text: Date of Application, 8th Dec., 1890
Complete Specification Left, 7th Sept., 1891-Accepted. 10th Oct., 1391
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Mills for Grinding Flint,
Stone, Bone, Glaze, and other like Substances.
I HENRY COTTON of Vine Street Hanley in the County of Stafford Manu-
facturer do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the construction of mills such as are
employed principally for grinding flint, stone, and other materials used in pottery,
one of the special objects of the invention being to cause the material or materials
under treatment to be brought with greater certainty and frequency between the
stones or runners and the bottom of the pan and consequently to be ground or
pulverized in a shorter time and with less expenditure of power than hitherto.
Another object is to diminish the cost of the runners or stones employed.
The class of grinding mills to which my improvements are particularly applicable
are constructed with a circular pan or bed of suitable diameter and material and
having the bottom lined or paved with hard stones. Through the centre of this
pan passes a vertical shaft which is caused to revolve by suitable gearing and is
provided with either curved or straight arms extending laterally therefrom by.
means of which large heavy stones or runners are carried or driven round in a
circular track over the paved bed before described so that the material to be
operated upon is ground or pulverized between the lower faces of the moving
stones and the paved bed.
66
"
The stones or runners are kept in position by a ring of wrought iron called the
slug iron
which is fastened to the arms and so placed within the pan as to leave
an annular space of about three or four inches between it and the inside of the
rim or wall of the pan, into which the centrifugal force evolved by the motion of
the stones causes the material to pass and as before stated it is one of the special
objects of my invention to provide means for causing the material being operated
upon to be removed from this space and repeatedly placed under the stones
or runners.
For the purposes of my invention I make the runners principally of cast iron
or other suitable material with recesses underneath so that they may be faced or
fitted with small stones or other suitable grinding surface suitable to the substances
to be operated upon.
By this means I obtain the necessary weight in the cast iron or other material
of which the runner is made and the grinding surface only is required to be of
stone or other suitable material whereby a considerable economy is effected.
Through each runner I form one or more conduits or pipes in a vertical or
nearly vertical position and as near as practicable to the inner edge of the same,
the said conduits being open at the top and bottom.
Above the pan at a suitable height I mount an annular trough connected by
arms to the vertical shaft so that it revolves therewith. A hole is made in the
bottom of this trough over the conduit of each runner and a pipe is fitted between
them to conduct the material from the trough into the conduit, the bottom of the
trough being made with inclines which cause the material to gravitate towards the
holes. Or if preferred the annular trough may be attached to and carried round
by the runners.
The material to be ground is introduced into the annular trough with a proper
proportion of water and passes by gravitation down the pipes or conduits in the
runners and as the latter are carried round or propelled over the bed of the pan
the material passes out at the bottom and becomes pulverized between the face
of the runners and the bottom of the pan as it passes from the inner edge of the

page_text: runners to the outer edge and thence into the annular space before named whence
it flows into a cistern, from whence it is pumped or otherwise conveyed up into the
before mentioned annular trough, and again passes through the conduits, and under
the runners and so on until it has been sufficiently ground.
I also
Or the material to be ground instead of being run off into a cistern outside the
pan may be allowed to accumulate to a suitable height in the pan in which I insert
a short pipe or conduit in the front of the runner leading into the upright
pipe or conduit that leads from the trough to the bottom of the runner.
provide a suitable inclined shoe or scoop so fixed to the front of the runner as to
compel the material under treatment to run up the incline and enter the conduit
or pipe and so pass under the runner again and again until it is sufficiently
ground.
By such means I can with advantage propel the runners at a greater speed and
can use sufficient runners to cover the whole area of the bottom of the pan, and
can use more arms than are at present used to propel the runners and with such
facilities I can grind the material in considerably less time, and with less
expenditure of power than is done by the method at present in use.
Dated this 6th day of December 1890.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Construction of Mills for Grinding Flint,
Stone, Bone, Glaze, and other like Substances.
I HENRY COTTON of Vine Street Hanley in the County of Stafford Manu
facturer do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to improvements in the construction of mills such as are
employed principally for grinding flint, stone and other materials used in the
manufacture of pottery, one of the special objects of the invention being to cause
the material or materials under treatment to be brought with greater certainty and
frequency between the stones or runners and the bottom of the pan, and con-
sequently to be ground or pulverized in a shorter time, and with less expenditure
of power than hitherto.
Another object is to diminish the cost of the runners or stones employed for
grinding.
The class of grinding mills to which my improvements are particularly applicable
are constructed with a circular pan or bed of suitable diameter and material, and
having the bottom lined or paved with hard stones. Through the centre of this
pan passes a vertical shaft which is caused to revolve by suitable gearing and is
provided with either curved or straight arms extending laterally or radially
therefrom by means of which large heavy stones or runners are carried or driven
round in a circular track over the paved bed before described so that the material
to be operated upon is ground or pulverized between the lower faces of the moving
stones and the upper surface of the paved bed.
$6
The stones or runners are kept in position by a ring of wrought iron called the
slug-iron" which is fastened to the arms, and is placed within the pan so as to
leave an annular space of about three or four inches between it and the inside of
the rim or wall of the pan into which the centrifugal force evolved by the circular
motion of the stones causes the material to pass, and as before stated it is one of the
special objects of my invention to provide means for causing the material being
operated upon to be removed from this space and repeatedly placed directly
between the stones or runners and the paved bed.

page_text: The nature of my said invention and the manner in which the same is to be
performed or carried into practical effect will be readily understood on reference
to the sheet of drawings hereunto annexed and the following explanation
thereof.
Fig. 1 on the drawings is a vertical section and Fig. 2 a plan view of a flint
grinding mill of the class above referred to with my improvements shown as
applied thereto, and Fig. 3 is a vertical section through one of the "runners."
Figs. 4 and 5 are similar views of a mill showing a modification of my invention
and Fig. 6 is a plan view of one of the runners.
a is the pan,
the paved bed, c the vertical shaft, d the curved radial arms fixed
thereto, and propelling the " runners e; fis the "slug-iron."
"
For the purposes my invention I make the runners e principally of cast iron or
other suitable material preferably with a mid-feather e as shown at Fig. 3, leaving
recesses underneath so that they may he faced or fitted with small stones e, or
other similar grinding surface suitable to the substances to be operated upon. By
this means I obtain the necessary weight in the cast iron or other material of
which the runner is made and the grinding surface only is required to be of
stone or other suitable grinding material, whereby a considerable economy is
effected.
Or if preferred, I sometimes make the runner in the form of an open box
(without the midfeather) as shown at Fig. 4; into which I drop the grinding
stones from above and back them up with rubble, pig iron, or other inexpensive
kind of ballast or weighting material.
Through each runner e I form one or more conduits or pipes g in a vertical or
nearly vertical position and as near as practicable to the inner edge thereof the
said conduits being open at the top and bottom.
About the top of the pan a or at a suitable height above the same I mount an
annular trough h connected to the arms d or to the vertical shaft e so that it revolves
therewith.
i
A hole is made in the bottom of this trough and a pipe (preferably made
of flexible material) is fitted between them (see Fig. 4) to conduct the material
from the trough into the conduit g the bottom of the trough being preferably
made with inclines ¹ (see Fig. 1) which cause the material to gravitate towards
the holes, or if preferred the annular trough may be attached to and carried round
with the runners e.
The material to be ground is introduced into the annular trough with a proper
proportion of water and passes by gravitation down the pipes or conduits y in the
runners and as the latter are carried round or propelled by the arms & over
the bed the material passes out at the bottom and becomes pulverized between
the face of the runners e and the bottom of the pan a as it passes from the inner
edge of the runners e to the outer edge and thence into the annular space outside
the slug-iron f whence it flows along the trough k (see Figs. 4 and 5) into a cistern
from whence it is pumped or raised by an elevator or otherwise conveyed by a
shoot m back again into the before mentioned annular trough and again passes
through the conduits g and through and under the runners e and so on until it has
been sufficiently ground.
Or the material to be ground, instead of being run off into a cistern outside the
pan a may be allowed to accumulate to a suitable height in the pan, in which case
I may introduce at such height a short pipe (horizontal or nearly so) in the front
of the runner leading into the upright pipe or conduit g and in front of this I may
provide a suitable inclined shoe or scoop so fixed to the front of the runners as to
compel the material under treatment to run up the incline and enter the conduit or
pipe and so pass through and under the runner again and again until it is
sufficiently ground.
By my improved means I can with advantage propel the runners at a greater
speed and can use sufficient runners to cover the whole area (or nearly so) of the
bottom of the pan and can use more arms than are at present employed to propel

page_text: the runners and with such facilities I can grind the material in considerably less
time and with less expenditure of power than by the apparatus at present
in use.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The improvements in the construction of mills of the class hereinbefore referred
to for grinding flint, stone, bone, glaze and other like substances substantially as
herein before described and illustrated by the drawings annexed.
Dated this 5th day of Sentember 1891.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.