Year: 1887

page_text: Date of Application, 2nd Nov., 1887
Complete Specification Left, 28th July, 1888
Complete Specification Accepted, 31st Aug., 1888
I, CHARLES JOHN POTTER of Heaton Hall, Newcastle, Cement Manufacturer, do
hereby declare the nature of this invention to be as follows:-
According to this invention in place of building up mill-stones with pieces of burr,
as is now usual, I make them of lumps of emery, cemented or otherwise held
together.
A convenient way of making the stones is to run concrete made of emery broken
into lumps and ceinent into an annular metal mould, the bottom of which gives a
smooth face to the stone; above a layer of this emery concrete, ordinary concrete
may be added, so as to give additional weight. The cylindrical sides of the annular
mould may be left attached to the block, so as to form the ordinary hooping.
When
such a stone is first used the cement between the lumps of emery quickly wears away,
leaving the emery thus giving the necessary roughness to the face to replace the
dressing of the burr.
Instead of ordinary cement any suitable fusible material may be used..

page_text: 1, CHARLES JOHN POTTER, of Heaton Hall, Newcastle, Cement Manufacturer, do
horoby declaro 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 :-
<<
"
According to this invention in place of building up mill stones with pieces of
burr as is now common I construct them of lumps of emery cemented together,
the emery being used in its native state, and the lumps being of considerable sizo say
an inch cube and upwards.
In making such stones I run concrete made of emery broken into lumps and
cement into an annular metal mould, the bottom of which gives a smooth face to the
stone, above a layer of this emery concrete ordinary concrete may be added so as to
give additional weight. The cylindrical sides of the annular mould may be left
attached to the block, so as to form the ordinary hooping. When such a stone is first
used the cement between the lumps of emery wears away more quickly than the
emery thus leaving shallow crevices between the lumps of the emery thereby giving
the necessary roughness to the face which replaces the dressing of the burr stones.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a full sized cross section of part of the grinding face of a mill stone
constructed according to my invention.
Figure 2 is a vertical section of a pair of stones to a smaller scale.
Figure 3 is a vertical section and Figure 4 is a plan of a modified stone.
Figure 5 is a vertical section and Figure 6 is an underside view of another modified
stone.
The drawings do not show the machinery whereby the stones are supported and
driven as this may be of any ordinary construction.
In Figure 1 a aro lumps of emery and 6 is the cement by which they are held
together.
I prefer to graduate the size of the lumps having the largest on the inside and the
smallest on the outside. c is the metal cylinder serving as a mould in the process of
manufacture and as a boop for the finished stone.
In Figures 2-6 c is the outer cylinder as before d is the inner cylinder e is the
emery concrete concreto of ordinary stone.
In Figures 3 and 4 g is an inner ring of "burr" or other suitable stone. This
arrangement is useful for rough grinding as the burr is more suitable than emery for
reducing any large pieces which may be put in to a size convenient for grinding by
the emery face.

page_text: In Figures 5 and 6 h is an inner ring of sandstone or ordinary cement concrete
which acts merely as a filling the grinding being performed by the emery surfaces.
This arrangement is suitable for fine grinding.
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 :-
1. A mill stone built up of lumps of emery cemented together substantially as
described.
2. A mill stone built up of lumps of emery cemented together the size of the lumps
decreasing from the centre outwards substantially as described.
3. A mill stone formed of a concrete of lumps of emery and Portland cement cast
into a cylinder substantially as described.
4. A mill stone having an inner ring of burr or other suitable stone and an outer
built up of lumps of emery substantially as described.
ring
Dated this 23rd day of July 1888.
CHARLES JOHN POTTER.