Improvements in or connected with Mills for Fine Grinding Mineral or other Substances, especially applicable for the Production of Cement.
Year: 1895

page_text: Date of Application, 2nd Apr., 1845
Complete Specification Left, 3rd Feb., 18:6-Accepted, 7th Mar., 1896
T
PROVISIONAL SPECIFICATION.
Improvements in or connected with Mills for Fine Grinding Mineral
or other Substances, especially applicable for the Production of
Cement.
We, WILLIAM GARNER of 1 Locksley Street, Limehouse, in the County of
Middlesex, Manager, and, EDWARD ARTHUR GLOVER of 88 Longbridge Road,
Barking in the County of Essex, Engineer, do hereby declare the nature of this
invention to be as follows:-
The invention relates to improvements in or connected with mills for fine
grinding mineral substances especially applicable for the production of cement.
The production of cement of good quality is largely dependent upon the degree
of fineness to which the constituents thereof are reduced and more especially the
hard particles or "clinker" and in order to obtain the best results it is the practice
to pass the cement materials to be ground, after being acted upon by the roughing
mill, several times through the finishing mill but this process is expensive inasmuch
as it occupies a great length of time and is destructive to the millstones and, as a
natural consequence, it is not generally adopted with the result that the cement
commonly produced is of inferior quality.
Now the object of the present invention is to obtain a mill which will, after the
material has been passed through the roughing mill, at one operation reduce the
material under treatment to the required degree of fineness to produce a cement
of the best quality.
In carrying the invention into effect the material which may be calcined flint,
phosphates, emery or the like is first crushed in any well known crushing machine
and it is then fed into an ordinary roughing mill by which it is broken down
sufficiently for subsequent fine grinding in the finishing mill.
Both the roughing and finishing mills are cased in to confine the dust arising
from the grinding operation and the latter is drawn off from the casing by means
of a fan or the like or the dust might be separated from the granular material by
means of an ordinary separator.
The roughing mill is connected by an inclined spout or pipe with the upper part
f the casing of the finishing mill or with a hopper leading thereinto.
Within the finishing mill are arranged two millstones one of which is fixed whilst
the other receives rotary motion through a driven shaft in the usual manner.
The faces of these stones instead of being dressed in the manner heretofore
adopted that is to say with about six or eight furrows in the central part or heart
of the stone and with a plain or undressed skirt; according to the present invention
the central part or heart of the stone is divided into a number of, for example
eight, sections, more or less, separated by lines arranged tangentially to a circle
drawn around the axis of the stone and the furrows are formed around the entire
circle of the heart of the stone whilst those of each section lie parallel with one of
its tangential sides but the angle or disposition of the furrows may be modified so
as either to accelerate or retard the delivery of the material according to the
purpose for which the mill is intended.
.
The skirt of the stone instead of being formed as heretofore is composed of
several segments of fine emery composition which are fixed in concentric segmental
iron frames or boxes of trough shape cemented and fixed to the stone proper by

page_text: means of strong iron hoops or bands and forming a skirt thereto and the emery
segments are formed upon their entire surface with suitably spaced radially
disposed furrows meeting the tangential furrows of the heart of the stone.
The segmental iron frames or boxes containing the emery composition are in
transverse section formed slightly dovetailed or undercut so that the emery
composition which, is introduced therein in a plastic state will upon setting be
firmly held in position.
In order to economise the emery composition each segmental frame, box or
trough is formed with a web or floor at a suitable distance from the surface in
order to support the emery composition and to limit the depth thereof.
According to this arrangement of parts the skirt may be readily renewed when
requisite whilst at the same time the iron faces of the frames, boxes or troughs
form a wearing surface which more or less protect the emery composition.
The back or upper part of the segments surrounding the rotary stone form boxes
to receive weighting or ballasting material such as lead for the purpose of
balancing the stone thus avoiding the necessity for cutting away the stone to
receive the ordinary lead weights.
By the means hereinbefore described that is to say by the peculiar dress given
to the stones and by the employment of the skirt of fine emery composition the
action of the mill is so much improved that the material under treatment issues
from the mill in a regular and fine state of division and perfect condition for use
in the manufacture of cement.
Although the invention is more especially intended for the grinding of mineral
substances it will be evident that it may be usefully employed for grinding other
materials.
Dated this 2nd day of April 1895.
WHITE & WOODINGTON,
27 Southampton Buildings, London, Agents.
COMPLETE SPECIFICATION.
Improvements in or connected with Mills for Fine Grinding Mineral
or other Substances, especially applicable for the Production of
Cement.
We, WILLIAM GARNER of 1 Locksley Street, Limehouse, in the County of
Middlesex Manager, and EDWARD ARTHUR GLOVER of 88 Longbridge Road
Barking in the County of Essex, Engineer, 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 :-—
The invention relates to improvements in or connected with mills for fine
grinding mineral or other substances especially applicable for the production of
cement.
66
The production of cement of good quality is largely dependent upon the degree
of fineness to which the constituents thereof are reduced, and more especially the
hard particles or
cliuker," and in order to obtain the best results it is the practice
to pass the cement materials to be ground after being acted upon by the roughing
mill, several times through the finishing mill, but this process is expensive inasmuch
as it occupies a great length of time, and is destructive to the millstones, and as a
natural consequence, it is not generally adopted with the result that the cement
commonly produced is of inferior quality.
Now the primary object of the present invention is to obtain a mill which will,
after the material has been passed through the roughing mill, at one operation
reduce the material under treatment to the required degree of fineness to produce a
cement of the best quality.

page_text: In carrying the invention into effect, the material which may be calcined flint,
phosphates, quartz emery, or the like, is first crushed in any well known crushing
machine, and it is then fed into a roughing mill by which it is broken down
sufficiently for subsequent fine grinding in the finishing mill in which it then
passes.
Within the finishing mill are arranged two millstones, one of which is fixed
whilst the other receives rotary motion through a driven shaft in the usual
manner.
*
The faces of these stones instead of being dressed in the manner heretofore
adopted, that is to say with about six or eight furrowed sections or quarters"
extending from the eye to the skirt; according to the present invention the central
part or heart of the stone is divided into a number of, for example eight, sections
more or less, separated by lines arranged tangentially to a circle drawn around the
axis of the stone, and the furrows are formed around the entire circle of the heart
of the stone, whilst those of each section lie parallel with one of its tangential sides
but the angle or disposition of the furrows may be modified so as either to
accelerate or retard the delivery of the material according to the purpose for
which the mill is intended.
The skirt of the stone instead of being formed as heretofore, is composed of
several segments of fine emery or other suitable composition which are fixed in
concentric segmental iron or other metal frames or boxes of trough shape, cemented
and fixed to the stone proper by means of strong iron hoops or bands and forming
a skirt thereto, and the emery segments are dressed upon their entire surface with
suitably spaced radially disposed furrows meeting the tangential furrows of the
heart of the stone.
The segmental iron frames or boxes containing the emery composition are in
transverse section formed slightly dovetailed or undercut so that the emery com-
position which is introduced therein in a plastic state will upon setting be firmly
held in position.
In order to economise the emery composition each segmental frame, box, or
trough is formed with a web or floor at a suitable distance from the surface in
order to support the emery composition, and to limit the depth thereof.
According to this arrangement of parts the skirt may be readily renewed
when requisite, whilst at the same time the metal faces of the frames, boxes,
or troughs form a wearing surface which more or less protects the emery
composition.
The back or upper part of the segments surrounding the rotary stone form boxes
to receive weighting or ballasting material such as lead for the purpose of balancing
the stone, thus avoiding the necessity for cutting away the stone to receive the
ordinary lead weights.
And in order that the said invention may be more clearly understood and readily
carried into effect, we will proceed aided by the accompanying drawings more fully
to describe the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a top view or plan of a pair of finishing stones constructed according
to the present invention, and in working position.
Figure 2 is a transverse section taken on the line 1-1 of Figure 1.
Figure 3 is a face view of the upper stone.
Figure 4 is a similar view to Figure 2, but showing the stones separated.
Figure 5 is a face view of one of the segmental metal frames or boxes
separately.
Figure 6 is a face view of a roughing stone dressed according to the present
invention.
Figure 7 is a vertical transverse section representing a pair of such stones in
working position.
In the several figures like parts are indicated by similar letters of reference.

page_text: Referring to Figures 1 to 5 a and a* represent respectively the upper and lower
stones a represents the skirt of the stone, and b represents the iron frame in which
the emery skirt is held.
The faces of these stones a a* when dressed in the manner heretofore adopted
have been formed with about six or eight furrowed sections or "quarters
extending from the eye to the skirt a¹.
According to the present invention however, the central part or heart of the
stone is divided into a number for example, six or eight sections, more or less a³
separated by lines a arranged tangentially to a circle or circles drawn around the
axis of the stone, and the furrows a are formed around the entire circle of the
heart of the stone, whilst those of each section a lie parallel with one of its
tangential sides a³, but the angle or disposition of the furrows a may be modified
so as either to accelerate or retard the delivery of the material according to the
purpose for which the mill is intended.
The skirt a' of the stone, instead of being formed as heretofore is composed of
several segments of fine emery composition which are fixed in concentric segmental
frames or boxes of trough shape formed of iron or other suitable metal, and which
iron boxes bare first cemented to the stone proper and then further fixed in position
by means of strong iron hoops or bands 2 which are shrunk thereon, the emery
segments a¹ forming a skirt to the stone.
The emery segments a¹ are formed upon their entire surface with suitably spaced
radially disposed furrows a meeting the tangential furrows at of the heart of the
stone.
The segmental iron frames or boxes b containing the emery composition a¹ are
in transverse section formed slightly dovetailed or undercut as shown more
particularly at Figures 2 and 4, so that the emery composition a¹ which is introduced
therein in a plastic state will upon setting be firmly held in position.
In order to economise the emery composition each segmental frame, box, or
trough b is formed with a web or floor 6' at a suitable distance from the surface or
face thereof in order to support the emery composition a¹, and to limit the depth
thereof, and thus economise the material.
According to this arrangement of parts the emery skirt a¹ may be readily
renewed when requisite by chipping out or otherwise partially or entirely removing
the emery composition from the segmental frames, boxes, or troughs b, and filling
up the same with new emery composition whilst at the same time the iron boxes
or segments serve another useful purpose, that is to say their faces form a wearing
surface which more or less protects the emery composition in the running of the
stones.
Furthermore the back or upper part of the segmental boxes b surrounding the
rotary stone a beyond the partition b¹ form boxes 6' which when necessary receive
weighting or ballasting material such as lead which may be cast therein for the
purpose of balancing the stone, thus avoiding the necessity for cutting away the
same to receive the ordinary lead weights.
Although it is generally preferable to dress the skirt in the manner herein before
described this dressing may if desired be omitted, leaving a skirt of emery
composition having a plain surface.
In the example given at Figures 6 and 7 the present invention so far as the
novel system of "dress" is concerned is shown applied to ordinary roughing
stones, that is to say the skirt a¹ in lieu of being formed of several segments of
emery composition consists of stone built up in segments and dressed with radial
furrows as herein before described, the stone being encircled by metal hoops b*
shrunk thereon in the manner hereinbefore described with respect to the previous
figures.
A convenient way of arranging a grinding mill of the character hereinbefore
described is to enclose both the roughing and finishing mills in suitable casings in
order to confine the dust arising from the grinding operation, the latter being
drawn off from the casing by means of a fan or the like, or the dust might be

page_text: separated from the granular material by means of an ordinary separator as is well
understood.
When so encased the roughing mill would preferably be connected by an inclined
spout with the upper part of the casing of the finishing mill, or with a hopper
leading thereinto.
Within the finishing mill would be arranged two millstones a a* of the character
represented at Figures 1 to 5, one of which a* would be fixed, whilst the other a
received rotary motion through a driven shaft in the usual manner, whilst within.
the roughing mill would be arranged a pair of stones of the character represented
at-Figures 6 and 7, or any other suitable form of roughing stones might be
employed for this purpose.
In practice the material which may be calcined flint, quartz, phosphates, emery,.
or the like is firet crushed in any well known crushing machine, and is then fed
into the roughing mill where it is ground down- sufficiently for subsequent fine-
grinding in the finishing mill; it is then passed into the finishing mili which by
reason of the peculiar construction of the stones, will at one operation reduce the
material under treatment to a sufficient degree of fineness to produce a cement
of the best quality.
By the means herein before described, that is to say by the peculiar dress at a
given to the stones, and by the employment of the skirt a' of fine emery composition,.
the action of the mill is so much improved that the material under treatment issues
therefrom in a regular and fine state of division and perfect condition for use in
the manufacture of cement.
In addition to the advantages hereinbefore pointed out it may also be stated that.
these stones when grinding "clinker" remain cool or approximately so, whereas.
the stones as hitherto constructed commonly become unduly heated or fired, causing
the stone to splinter and split off round the periphery thereof, thus more or less
destroying the stones and involving considerable expense for repairs, whilst another
advantage is that the roughing stones dressed in the manner hereinbefore shown
and described with respect to Figures 6 and 7 may with advantage be run farther
apart than ordinary roughing stones, thus considerably increasing the capacity
of the mill, reducing the wear and tear and consequently lessening the cost of
running.
We have not thought it necessary to illustrate by drawings the connected casings
of the roughing and finishing mills, as such arrangement is well known in other
mills, and forms no part of the present invention.
In lieu of the emery composition as a filling for the segmental boxes or cases bª.
any other suitable material may be employed for that purpose.
Although the invention is more especially intended for the grinding of mineral
substances it will be evident that it may be usefully employed for grinding other
materials, or for hulling grain or seed.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
"
1. In a mill stone the combination of a heart dressed or divided into a number of
" quarters
or sections formed with sides shaped as tangents to a circle or circles
drawn around the theoretical axis of the stone, and with a number of furrows.
arranged parallel to one of such sides and with a skirt formed with radially
arranged furrows in continuation of the tangential furrows of the quarters.
substantially as herein shown and described.
2. In combination with a mill tone a skirt formed of segmental metal boxes,.
troughs, or frames filled with emery composition or the like substantially as herein
shown and described.
3. In a mill stone the combination of a heart formed of stone and a skirt formed
of emery composition or the like substantially as herein shown and described.
L
4. In combination with a mill stone several segmental metal boxes, troughs, or

page_text: frames clamped around the periphery thereof by means of iron hoops or otherwise,
and formed in cross section of a more or less dovetailed shape in order to securely
hold a filling of emery composition or the like substantially as herein shown and
described.
5. In combination with a mill stone several segmental metal frames, boxes, or
troughs secured around the periphery thereof and divided by a partition or web
into two parts, one to receive emery composition or the like, and the other lead
or other ballast for balancing the stove substantially as herein shown and described.
6. In a mill stone the combination of a heart dressed or divided into a number
of " quarters or sections formed with tangential furrows and a skirt formed of
several segmental metal boxes, troughs, or frames clamped around the heart and
filled with emery composition or the like dressed with radially-arranged furrows
in continuation of the tangential furrows of the "quarters". substantially as herein
shown and described.
"
Dated this 1st day of February 1896.
WHITE & WOODINGTON,
27 Southampton Buildings, London, Agents.