Improvements in Mills for Grinding Cement and other matters.
Year: 1892

page_text: Date of Application, 19th May, 1892
Complete Specification Left, 20th Feb., 1893-Accepted, 25th Mar., 1893
PROVIDIUNAL SIDUIFICATION.
Improvements in Mills for Grinding Cement and other matters.
1, THOMAS CASTLE, of Strood Esplanade, Rochester, Cement Manufacturer do
hereby declare the nature of this invention to be as follows:-
This invention has for its object improvements in mills for grinding cement and
other matters.
In the improved mill the base consists of an annular trough fixed on a suitable
foundation. The trough has a renewable inner bottom or lining which serves as a
grinding surface; it operates in conjunction with hard balls or spheres which are
made to roll around the trough. Upon the balls a disc or circular casting rests
and there is an annular groove or track on the underside of the disc to receive the
balls. The disc has also upon it drivers projecting down between the balls and
these when the disc is driven as hereinafter described push the balls onwards
around the trough. On the upper face of the disc a second grinding trough is
formed; it is like the lower trough and concentric with it but of smaller diameter;
this trough is also provided with a renewable inner bottom or grinding surface.
A second set of grinding balls operates in the upper grinding trough and on theso
balls an upper disc or cover rests. The cover is held down to the foundation by
adjustable screw bolts.
The driving shaft is vertical and its upper end is made to engage with the
intermediate or driving disc. The driving shaft is connected by a joint which
allows a sufficient amount of freedom.
The material to be ground is fed in through a central hole in the upper disc or
cover and it is first ground in the upper trough; it passes under the balls from
within outwards and then descends by holes in the driving disc to the lower
trough where a second grinding takes place. In the lower grinding trough the
material again passes under the balls to outlets on the exterior of the grinding
track. Pressure is exerted upon the upper surface of the driving disc by adjustable
rollers carried by the upper disc or cover. The upper set of grinding balls also
exert a downward pressure upon the driving disc. By this arrangement a double
grinding of a very effectual nature is obtained; and this by means of a compact and
comparatively inexpensive machine.
My invention also applies to mills in which edge runners are employed. The
pan is made to rotate as usual and outside the path of the runners the bottom of
the
pan is formed of gratings. Beneath the gratings an annular shelf or surface
is provided upon the pan to receive the material which passes through the gratings
in a doughy or pasty condition.
A receiving trough fixed outside the pan meets the shelf tangentially, it receives
the material, leads it away and delivers it where required.
When the material is to be ground in a dry state I provide a shelf to receive it
as it descends through the grating as above stated. I attach this shelf to the pan
by its outer edge and arrange for the removal of the material from within the
circumference of the shelf in place of from without as I do when working with a
moist material.
The mouth of the receiving trough takes the material from the shelf and directs
it inwards towards the centre where provision is made for the material to descend
and it is delivered beneath the mill.
Thus the delivery of the ground material when of a semi-solid nature is very
conveniently effected.
Dated thin 10th 1. M 1000
CARPMAEL & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Mills for Grinding Cement and other matters.
I, THOMAS CASTLE, of Strood Esplanade, Rochester, Cement Manufacturer,
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 has for its object improvements in mills for grinding cement and
other matters.
In the improved mill the base consists of an annular trough fixed on a suitable
foundation. The trough has a renewable inner bottom or lining which serves as a
grinding surface; it operates in conjunction with hard balls or spheres which are
made to roll around the trough. Upon the balls a disc or circular casting rests and
there is an annular groove or track on the under-side of the disc to receive the balls.
The disc has also upon it drivers projecting down between the balls and these when
the disc is driven as hereinafter described push the balls onwards around the trough.
On the upper face of the disc a second grinding trough is formed; it is like the
lower trough and concentric with it but of smaller diameter, this trough is also
provided with a renewable inner bottom or grinding surface. A second set of
grinding balls operates in the upper grinding trough and on these balls an upper
disc or cover rests. The cover is held down to the foundation by adjustable screw
bolts.
The driving shaft is vertical and its upper end is made to engage with the inter-
mediate or driving disc. The driving shaft is connected by a joint which allows a
sufficient amount of freedom.
The material to be ground is fed in through a central hole in the upper disc or
cover and it is first ground in the upper trough; it passes under the balls from
within outwards and then descends by holes in the driving disc to the lower
trough where a second grinding takes place. In the lower grinding trough the
material again passes under the balls to outlets on the exterior of the grinding
track. Pressure is exerted upon the upper surface of the driving disc by adjustable
rollers carried by the upper disc or cover. The upper set of grinding balls also
exert a downward pressure upon the driving disc. By this arrangement a double
grinding of a very effectual nature is obtained and this by means of a compact
and comparatively inexpensive machine.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawing hereunto annexed.
DESCRIPTION OF THE DRAWING.
. The annexed drawing shows a vertical section of a mill in accordance with
my invention.
a is an annular trough which forms the base of the mill; it is securely fixed
upon a suitable bed b and is provided with a renewable lining a'.
c c are hard
spheres preferably of chilled cast iron and the lining a¹ upon which the spheres
bear may be of the same material. d is a disc or circular casting made in one
or more parts and resting upon the balls cc; in it another annular trough is
formed which also receives a lining d' presenting a hard grinding face.
ee are other
hard spheres bearing against the grinding face of the lining . f is an annular
cover which rests upon the balls e; it is made in two parts and the upper part
is provided with four or other number of radial arms f₁f. Screws and nuts g g
connect the arms f¹ with the lower trough a; springs may if desired be provided
to give elasticity to the connection between the cover and the lower trough.
hh are adjustable pressure rollers carried by the arms ff and bearing upon
the top of the disc d. Springs may also be provided in connection with these

page_text: pressing rollers. i is the driving shaft, a fork at its upper end embraces the
bark which is held in lugs upon the disc d so that the disc revolves with the
shaft. The outer ring of the disc d is furnished with driving projections d'ď
which drive the spheres e c around the track as fast as the disc d itself rotates.
ff are projections on the cover f; they are analogous to the drivers d but
serve to prevent the balls e e travelling with the disc d. 1 is the eye or opening
by which the material to be ground is fed into the mill. d³ & are openings in the
disc d by which the partially ground material having been crushed beneath the
balls e passes to the under side of the disc d into the base trough a.
The material when it is completely ground is delivered at the outside around the
circumference of the base trough a and is removed in any convenient manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
A mill substantially as described with two tiers of grinding spheres or balls and
a rotating disc between; a cover above the upper tier of balls; projections
controlling the grinding balls and provision for the passage of the material from
tier to tier as herein set forth.
Dated this 17th
1000