AN IMPROVED MILL FOR GRINDING AND PULVERIZING PAINTS AND VARIOUS VEGETABLE ANDAL
Year: 1854

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street,
in the City of London, Patent Agent, for the Invention of "AN IMPROVED
MILL FOR GRINDING AND PULVERIZING PAINTS AND VARIOUS VEGETABLE AND
PROVISIONAL SPECIFICATION left by the said Richard Archibald Brooman
at the Office of the Commissioners of Patents, with his Petition, on the
24th June 1854.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention
for AN IMPROVED MILL FOR GRINDING AND PULVERIZING PAINTS AND VARIOUS
VEGETABLE AND MINERAL SUBSTANCES," (communicated to me by a foreigner
residing abroad,) to be as follows:-
This Invention consists of an improved mill for grinding or pulverizing
various vegetable and mineral substances, as pain. crystals, &c. The
principle consists in the revolution of one or more mullers within an annular
shaped concave bed, the said mullers revolving also about an axis; and as the
surfaces in contact with the concave bed pass over unequal spaces in equal
times, viz., the time of a revolution about the central axis, the abrading or
disintegrating action is thence obtained, as will more fully appear from the
following description. of the construction and operation of the mill :-The

page_text: Drawing annexed represents a vertical section of the mill. At the bottom
of a proper curb is placed the lower bed stone A; this may be of metal or
stone, or other suitable materials. Through the centre there is a hole for the
main shaft to pass, and outside of this there is an annular concave a, cut or
cast, as may be. This concavity is shewn as formed on two radii, the centres
being upon the centres of the spindles of the mullers. The mullers are shewn
at B. Their diameters are about equal to the width of the annular concave a,
and they are cylindrical in shape at their sides, while their bottoms are
hemispherical, and such, that a section through the middle would coincide
with a section through A on the same line, as shewn at a¹. The mullers are
attached to spindles, revolving in sockets or boxes b; these latter are affixed
together, and to the centre shaft by arms c, which are at liberty to move up
and down on the centre shaft, while they are at the same time caused to
revolve by it, there being a feather and groove to match cut for that purpose.
This up and down motion is to allow the mullers to rise and fall, according as
there is more or less thickness of material on the bed stone. The articles to
be ground are fed through a hollow in the shaft, being delivered out through
a hole at its side, near the surface of the bed stone. There is here a means
of regulating the aperture of the hole, so that the amount fed through may be
governed. Around the shaft there is a tube D fitted, so as to be allowed to
move up and down; this is supported or kept up by the mullers, on which
it rests by the arms c.
In the side of D there is a hole i, standing opposite
to the hole in the shaft. When there is nothing under the mullers, so that
their bottoms rest upon the bed, these two holes are directly opposite to each
other; then the materials may pass through at a full feed as the mullers begin
to rise; in consequence, the tube D is also lifted, and its hole passes by the
other, and thus effects the contracting of the opening, or wholly cuts it off,
whereby the feed is regulated to any degree required.
The operation of the mill is as follows:-The main shaft being set in
motion, the mullers B will be carried round their lower ends, sliding along in
the annular groove a.
Now, it is evident that the space passed over by the
inner corner of the muller is less than that at the outer, this space gradually
increasing from the centre to the circumference. This causes the rotation of
the mullers, and thus the cross action or lines, crossing lines necessary to
produce the complete disintegration of certain materials, is effected. As the
hemispherically shaped end of the muller fits the groove only in the cross
section, the front and back parts are elevated above its surface, by which
means the materials to be ground are passed under. The paint or other
material is then let on through the hopper k, and is delivered out of the hole

page_text: o, upon the bed stone being governed in quantity by the relative positions of
the two holes, as before described. If the substance to be ground is in the
dry state, and it is desired to reduce it to the utmost degree of fineness, the
operation is continued until the particles become light enough to be affected
by the currents of air generated by the revolution of the mullers, when the
particles will rise and pass over the curb, and subside in the casing sur-
rounding the mill, as in the ordinary chasers. In grinding some substances
it may be found that the mullers will not rotate in the boxes b. as, for instance,
when grinding paints in oil, and the matter has been reduced to an extreme
fineness. The rotation of the mullers may in such cases be secured, by affixing
a toothed wheel to the upper end of their spindles, which shall gear into teeth
on the inside of a circular casting, affixed permanently to the bed on which
the stone rests. As now the mullers are driven around in the annular groove
by the arms c, they will be made to rotate on their spindles with a speed due
to the relative proportion of the wheels and the circular casting.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal Patent
Office on the 23rd December 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of June, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Richard Archibald Brooman, Iler special licence that I, the said
Richard Archibald Brooman, my executors, administrators, and assigns, or
such others as I, the said Richard Archibald Brooman, my executors, admi-
nistrators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "AN IMPROVED MILL FOR GRINDING AND PULVERIZING
PAINTS AND VARIOUS VEGETABLE AND MINERAL SUBSTANCES," Communicated to me
by a foreigner residing abroad, upon the condition (amongst others) that I,

page_text: the said Richard Archibald Brooman, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Richard Archibald Brooman, do hereby
. declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the Drawings hereunto
annexed, that is to say:-
This Invention consists in certain improvements in that class of mills for
reducing or pulverizing mineral or vegetable substances, in which the
abrading or disintegrating action is obtained by the revolution of one or
more nullers within an annular shaped concave bed, the said mullers
having also a revolution about their own axes; and the nature of these
improvements will be apparent from the following description of the con-
struction and operation of the improved mill, as shewn in Figures 1, 2, and 3
of the Drawings annexed. At the bottom of a proper curb is placed the
lower bed stone A, which niay be of metal, stone, or other suitable material.
Through the centre there is a hole for the main shaft to pass, and outside of
this there is an annular concave a, cut or cast, as may be. This concavity is
shewn in the sectional view, Figure 2,, as formed on two radii, the central
points of which are in the line of the axes of the mullers; but these radii
should be somewhat greater than the semidiameter of the muller, for a
purpose to be herein-after stated. The mullers are shewn at B. They are
cylindrical in shape at their sides, and their bottoms are in the form of a
segnient of a sphere, and such, that a vertical section on the plane of the axis
of the muller and of the central shaft would coincide with a section through
the bed A taken in the same plane, as shewn at a³, Figure 2. The mullers
are attached to spindles, revolving in sockets or boxes b, connected with each
other, and with the centre shaft by arms c,-which have vertical play on the
shaft, while they are at the same time caused to revolve with it by a feather
on the shaft, working in a groove for that purpose. The vertical play is to
allow the mullers to rise and fall, according as there is more or less thickness
of material on the bed stone. Some kinds of articles to be ground may be
fed through a hollow in the shaft, if desired, being delivered out through a
hole at its side, near the surface of the bed stone. There is here a means of
regulating the aperture of this hole, so that the amount fed may be governed.
Around the shaft there is a tube-D, fitted-so as to move up and down, and

page_text: supported by the mullers, on which it rests by the arms c. In the side of D
there is a hole (i), standing opposite to the hole in the shaft. When there
is nothing under the mullers, so that their bottoms rest upon the bed, those
two holes are directly in line with each other, and then the substances may
pass through at a full feed as the mullers begin to rise; in consequence, the
tube D is also lifted, thus partially or wholly closing the hole in the shaft, as
the case may be.
The operation of the mill is as follows:-The main shaft being set in
motion, the mullers B will be carried round in the annular concave, having
by this motion revolution about their own axes, from the fact that the space
passed over by the outer edge of a muller is greater than that by the inner
edge. The substance to be operated upon passes under the muller, for the
reason that the rounded end of the muller fits the bed stone only in the cros
section, and the front and back parts are thus elevated, as seen in Figure 3.
The concavity of the bed being made with a radius greater than the semi-
diameter of the muller, a space is thereby left at a", Figure 2, into which the
superabundant material may pass when the feed happens to be too abundant,
and thus choking or clogging is avoided. If the lower end of the muller
were truly hemispherical, and the annular concave made to coincide with that,
it is obvious that small pieces of the matter to be operated upon between the
surfaces would, when near a horizontal line passing through the central
point of the sphere, raise the bottom of the muller to a comparatively great
distance from the bed stone, thus destroying the useful effect, or clogging and
stopping the mill.
The matter may be fed through the hopper and hollow shaft, being
governed in quantity by the relative positions of the two holes, as described; or
if quartz, broken flint, &c., may be put in over the top, as usual. If vegetable
or other matter in a dry state is to be ground, and it is required to be reduced
to the utmost degree of fineness, the operation may be continued until the
particles become light enough to be affected by the currents of air generated
by the revolution of the mullers, when those particles will rise over the curb
and subside, as in ordinary chasers, in the casing surrounding the mill.
In grinding some substances it may be found that the mullers will not
rotate in the boxes b, as, for instance, when in grinding paints in oil, and the
matter has been reduced to an extreme fineness. The rotation of the mullers
may in such cases be secured, by affixing a toothed wheel to the upper end of
the spindle, which shall mesh into teeth on the inside of a circular casting
affixed permanently to the bed on which the stone rests, as clearly shewn in
Figure 1. As now the mullers are driven around in the annular groove by

page_text: the arms c, they will be made to rotate on their spindles with a speed due to
the relative proportion of the wheels and the circular casting.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that what I claim is,
forming the grinding surfaces of the muller and of the annular concave in
the bed stone with a radius of such greater extent, as compared with the
semidiameter of the muller, that an excess of material shall have space into
which to pass, thereby obviating the packing or clogging between the sides of
the muller and of the said groove, the whole being constructed and operating
substantially as hercin-before set forth.
In witness whereof, I, the said Richard Archibald Brooman, have here-
unto set my hand and seal, this Twenty-first day of December, One
thousand eight hundred and fifty-four.
K. A. BRUUMAN. (L.S.)