IMPROVEMENTS IN THE GRINDING OF PIGMENTS AND OTHER SUBSTANCES REQUIRING TO BE MECHANICALLY SUSPENDED AS A FINE POWDER IN OIL, WATER, OR OTHER LIQUID, AND IN MILLS OR APPARATUS APPLICABLE THEREFOR."
Year: 1879

page_text: LETTERS PATENT to Theodore Holmes, of Newcastle upon Tyne, in the County
of Northumberland, for the Invention of "IMPROVEMENTS IN THE GRINDING
OF PIGMENTS AND OTHER SUBSTANCES REQUIRING TO BE MECHANICALLY
SUSPENDED AS A FINE POWDER IN OIL, WATER, OR OTHER LIQUID, AND IN
MILLS OR APPARATUS APPLICABLE THEREFOR."
Sealed the 24th February 1880, and dated the 1st September 1879.
PROVISIONAL SPECIFICATION left by the said Theodore Holmes at the Office
of the Commissioners of Patents on the 1st September 1879. ·
THEODORE HOLMES, of Newcastle upon Tyne, in the County of Northumberland.
"IMPROVEMENTS IN THE GRINDING OF PIGMENTS AND OTHER SUBSTANCES
REQUIRING TO BE MECHANICALLY SUSPENDED AS A FINE POWDER IN OIL, WATER,
OR OTHER LIQUID, AND IN MILLS OR APPARATUS APPLICABLE THEREFOR."
This Invention has for its object the grinding of pigment and other substances
usually in a liquid menstruum such as oil, so as to give as much and as uniform
trituration as possible while once passing through the mill.
In bearings in a suitable framing I arrange a granite roller, rotating at a speed
suitable for the material to be ground. Against this I place a feed roller running
in an opposite direction but at a slower speed of surface, so that the large roller
may feed itself from the lesser. Against the periphery of the large roller, beyond
or after the feeding roller, I place a concave granite block, whose concave surface is
approximately the same curve as the roller, but with its receiving edge preferably
a little retreating from the surface of the roller, so that it may not act as a scraper but
may allow the pigment to enter beneath it. This block has a reciprocating motion
in the direction parallel with the axis of the roller, so as to allow of equal wear of
the block and roller, and also to assist the grinding. Care should be taken that
the reciprocations of the block are not in any way synchronous with the revolutions
of the roller, as in that case part of the value of the reciprocating motion will be
lost, as the same surface of block will at every revolution pass over the same surface

page_text: of the roller. Beyond the block I place a scraper, which scrapes from the granite
roller the pigment as it is ground.
I have previously spoken only of granite, but both rollers and block may be of
porcelain, chilled iron or steel, or of other material than granite, and in the grinding
of some chemicals this may be necessary.
Although, too, this mill is designed chiefly as a paint mill, it may also be used in
chemical or metallurgical works to obtain an intimate mixture of materials in the
manufacture of chloride of aluminium and other processes. It might also probably
be of use in grinding cocoa and other edibles where an intimate mixture of materials
is required.

page_text: SPECIFICATION'in pursuance of the conditions of the Letters Patent filed by
the said Theodore Holmes in the Great. Seal Patent Office on the 1st March
1880*
4
THEODORE HOLMES, of Newcastle-upon-Tyne,. in the County of Northumber-.
land. "IMPROVEMENTS IN THE GRINDING OF PIGMENTS AND OTHER SUBSTANCES
REQUIRING TO BE MECHANICALLY SUSPENDED AS A FINE POWDER IN-OIL, WATER,
OR, OTHER LIQUID, AND IN MILLS OR APPARATUS APPLICABLE. THEREFOR.".
This Invention has for its object the grinding of pigment and other" substances
usually in a liquid menstruum such as oil, so as to give as much and as uniform
trituration as possible while once passing through the mill. It is best described by
aid of the accompanying Drawings, in which Figure-1 is front elevation,, and Fig. 2
side.elevation of my apparatus as now in use.
of
On the main driving shaft A in bearings Al in a suitable framing C.I arrange a
granite roller A² rotating at a speed suitable for the material to be ground. Against
this I place a feed roller B² running on shaft B in an opposite direction, but at a speed
of surface slower than that of A, so that the roller A² may feed itself from the lesser
roller B. This feed roller is held to the face of the main roller by spring B₁ and
adjusting screw B* bearing against its bearings, and is driven from shaft A by means
spur gearing A³, B³. Against the periphery of the roller A², beyond or after the
feeding roller B2, I place a concave block D; preferably granite, whose concave
surface is approximately the same curve as the roller A, but with its receiving
edge preferably a little retreating from the surface of the roller, so that it may not
act as a scraper but may allow the pigment to enter beneath it. This block D is
supported in bearings or slides D¹, and has a projecting piece D2 at the end. In
slots in this works an arm E pivoted on bracket F, and armed at the other end
with a pin or thimble working in a groove cam G, which works loose on the main
shaft, but is rigidly attached to spur wheel G', which is driven from the main shaft
at a speed much reduced by means of intermediate gear wheels G2, G3, and G.
This groove cam G and lever E¹ give the block D a slow reciprocating motion in
the direction parallel with the axis of the roller, so as to allow of equal wear of the
block and roller, and also to assist the grinding. Care should be taken that the
reciprocations of the block are not in any way synchronous with the revolutions of
the roller, as in that case part of the value of the reciprocating motion will be lost;
as the same surface of block will at every revolution pass over the same surface of
the roller. Beyond the block I place a scraper H which scrapes from the granite
roller A² the pigment as it is ground. This scraper is accurately adjusted by the
set screws I in one of the arms J, J, which arms are pivoted on axes K. Attached
to said arms and scraper I place spout L for delivering the ground paint.
In working the machine the unground pigment is delivered in advance of the
feed roller B, being kept from running off the ends of the rolier A² by means of
the hopper plates M regulated by screws M¹. The feed roller feeds it in a uniform
layer over roller A2; it then passes between block D and roller A², and escaping
from block D on the other side is scraped off by the scraper.
I have previously spoken only of granite, but both rollers and block may be of
porcelain, chilled iron or steel, or of other material than granite, and in the grinding
of some chemicals this may be necessary. Although, too, this mill is designed
chiefly as a paint mill, it may also be used in chemical or metallurgical works to
obtain an intimate mixture of materials. It might also probably be of use in
grinding cocoa and other edibles where an intimate mixture of materials is
required.
Having now described my Invention, and the best mode known to me of carrying
it into effect, I wish it to be understood that I do not claim the principle broadly
of using feed rollers, concave blocks, or scrapers separately in conjunction with

page_text: rollers, but that what I believe to be new and desire to protect, under the herein-
before in part recited Letters Patent is,
First. The grinding of pigments and other solid substances requiring to be finely
suspended in a liquid or semi-solid menstruum by feeding the materials between a
feed roller and main roller driven at differential surface speeds, and thence between
the main roller and a concave block, one or other of the two latter having a recipro-
cating motion parallel with their touching surfaces..
Second. The manufacture of mills for grinding pigments, cocoa, or other like
substances with main and feed roller travelling at different surface speeds, the
main roller working in combination with a concave grinding block having a reciprocal
motion relatively to the said roller.
Third. The general arrangement of machinery for the wet grinding of pigments,
cocoa, and other like materials, substantially as described.
In witness whereof,
the said Theodore Holmes, have hereunto set my hand
and seal, this Twenty fourth day of February, in the year of our Lord One
thousand eight hundred and eightv.
Witnessed by
THOMAS DAVID ALLEN,
19, Hamilton St.,
Newcastle-on-Tyne.
THEODORE HOLMES. (L.S.)