Improved Composite Millstone.
Year: 1892

page_text: Date of Application, 22nd Mar., 1892
Complete Specification Left, 20th Dec., 1892-Accepted, 28th Jan., 1893
PROVISIONAL SPECIFICATION.
Improved Composite Millstone.
I, WILLIAM SAMUEL SNEADE, of Charters Street Liverpool in the County
of Lancaster, Millstone Manufacturer do hereby declare the nature of this invention
to be as follows:-
My invention relates to certain improvements in the construction of composite
millstones for grinding cement, minerals and other granular substances or materials,
also to the use and employment of basic and other slag, i.e. the dross derived from
the smelting of iron, copper and other metallic substances, as the principal material
composing my said improved millstone, either in large solid pieces fitted and
cemented together or broken up and made into a concrete with a suitable cement
and moulded into blocks, or re-melted and cast into blocks or sections for the con-
struction of millstones of various diameters and "dress." Also, to the formation
of the "swallow" and leads or "furrows" of a material different to and softer than
the material composing the "lands or grinding faces.
"
In one form of my improved millstone the leads or furrows, which extend to the
periphery, are composed of soft stone, cement or other suitable material or com-
pound and the intervening spaces or grinding faces are composed of large pieces of
the aforesaid slag fitted and cemented together, or of a concrete consisting of
pieces of slag as aforesaid mixed with a proper proportion of portland or other
cement.
In another form of my improved millstone the outer portion or "skirt" is com-
posed of a complete ring of blocks of slag fitted and cemented together, or, of the
aforesaid concrete. The swallow and furrows, composed, as in the other form, of a
softer material, extend only to the said ring and the intervening spaces are filled in
either with blocks of slag or with a concrete of somewhat coarser grade than that
composing the outer ring or skirt.
I do not confine myself absolutely to the forms of millstones as herein described,
I may slightly modify the disposition of the materials composing my improved
composite millstone, my said invention consists chiefly in the application and
employment of the slag or dross derived from the smelting of metallic substances
for the purpose stated and the formation of the swallow and leads or furrows of a
material different to and softer than the material composing the lands or grinding
faces.
Dated this 21st day of March 1892.
COMPLETE SPECIFICATION.
Improved Composite Millstone.
I, WILLIAM SAMUEL SNEADE of Charters Street Liverpool in the County of
Lancaster, Millstone 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 :-
My invention relates to improvements in the construction of composite millstones
for grinding cement, minerals and other granular substances or materials; also to
the use and employment of basic or other slag, i.e. the dross derived from the
smelting of iron, copper or other metallic substances, as the principal material
composing my said improved millstone, either in large solid pieces in its natural
or crude state fitted and cemented together; broken up and made into a concrete
Prine R71

page_text: with a suitable cement and moulded into blocks; or remelted and cast into blocks,
sections or other forms for the construction of millstones of various diameters and
"dress." Also to the "blowing" of the slag while in a molten state for the
purpose of rendering it porous or spongy so that it shall possess better cutting and
grinding properties. Also to the mixing with the slag, while in a molten state,
materials such as granulated emery, corundum or other similar hard substances
or materials for the purpose of imparting to it a keener "grit" or grinding
property.
66
In my improved millstone I construct the swallow, i.e., that portion immediately
surrounding the centre aperture or 'eye," also the furrows or leads radiating
therefrom, of French buhr or other suitable stone or cement and the intervening
spaces or grinding faces are composed of slag as aforesaid used in any of the forms
or conditions already described.
Upon the sheet of drawings hereunto appended I shew two forms of my improved
millstone.
In Fig. 1, A is the swallow composed of stone, cement or other suitable material
or compound. B. B. are the grinding faces composed of slag either in solid blocks
or in small pieces made into a concrete with a suitable cement or binding material.
C. C. are the furrows or leads composed of stone, cement or other suitable material
softer than the aforesaid slag.
In Fig. 2 the swallow grinding faces and furrows are constructed similarly to
Fig. 1, but instead of carrying the ordinary grinding faces and furrows out to the
periphery I form an outer ring or "skirt" of slag, either crude, mixed with a
gritty substance or porous, and it may be made in one piece cast to shape or
formed of concrete or of pieces fitted and cemented together.
The "blowing" of the slag for the purpose of rendering it porous is accomplished
as follows: The molten slag as it issues from the furnace or after being re-melted
is run into moulds of the shape required, having finely perforated bottoms up
through which air is forced causing the slag to bubble as it cools, it may thus be
made of any desired degree of porosity.
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. In the construction of composite millstones the employment of metallic slag
for the formation of the grinding faces, either in its natural or crude state; mixed,
while in the molten state, with hard gritty substances such as emery or corundum;
or rendered porous by "blowing'
in the manner and for the purpose herein
described.
"
2. The combination with slag as aforesaid of French buhr or other stone or
cement for the formation of the swallow and furrows of composite millstones as
herein described.
3. The method of rendering the slag porous by forcing air through it while in a
molten state, for the construction of composite millstones as herein de scribed.
Dated this 19th day of December 1892.
WILLIAM SAMUEL SNEADE.