IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR ASSORTING PULVERIZED MATERIALS
Year: 1881

page_text: LETTERS PATENT to Arthur William Lovell Reddie, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Patent Agent, for an
Invention of IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR
ASSORTING PULVERIZED MATERIALS." A communication from abroad by
Woldemar Kracht, of the Begitza Station of the Orel-Vitebsk Railway, in
the Empire of Russia.
PROVISIONAL SPECIFICATION left by the said Arthur William Lovell
Reddie at the Office of the Commissioners of Patents on the 17th March
1881.
ARTHUR WILLIAM LOVELL REDDIE, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Patent Agent. "IMPROVEMENTS IN THE METHOD OF
AND APPARATUS FOR ASSORTING PULVERIZED MATERIALS." [A communication
from abroad by Woldemar Kracht, of the Begitza Station of the Orel-Vitebsk
Railway, in the Empire of Russia.]
The ordinary process of elutriation or water washing serves to separate from a
mass of hard material the pulverized parts which are deposited in layers corre
sponding to their specific weight. This generally employed process is however
open to objection in certain cases in which it becomes desirable to employ other
means, especially when water is not to be had in sufficient quantity at the place
where this process is carried on, or in case the quality of the water is liable to
alter the nature of the pulverized material. Besides elutriation is altogether
inapplicable for soluble matters which must be separated by a very complicated
and costly process of sifting through-sieves of different gauge. Moreover elutriation
is inapplicable, wherever the physical and chemical nature of the pulverized
matter is altered by the action of water as in the case in the manufacture of
cement.
All these drawbacks are aggravated by the necessity of drying the material
after elutriation, causing not only a great loss of time, but also requiring con-
siderable space and expense for fuel.

page_text: By the present Invention the separation of pulverized hard materials, according
to their density, is effected, dispensing with water or any other liquid, as well as
with sifting. This method, which may be conveniently called a dust blowing
process, consists in the use of a current of air within a specially constructed
apparatus.
A drum made of cast or wrought iron or some other suitable material is fixed on
a hollow axle, and slowly rotates together with it. This rotation may be effected
by any convenient means. The hollow axle, perforated on its sides, is divided
midway of its length by a partition in such manner that the two halves can only
communicate by way of the inside of the drum. One end of the axle is connected 1
with the pipe leading from a fan or any other blast apparatus for driving a current
of air through the axle into the drum wherein the pulverized material is constantly
in motion and undergoing the process of dust blowing.
The air current upon entering into the drum by the perforations in one half of
the axle has a tendency towards the perforations in the opposite half of the axle, 1
carrying along with it the finest particles of the pulverized matter into a pipe, by
which they are conveyed to a depositing and sorting chamber, consisting of several
divisions separated by partitions which alternately reach to within a short distance
of the top or bottom of this chamber. In turning at the ends of the partitions the
air current on its way deposits the particles which it has carried along out of the
drum, and which are disposed according to their degree of density within funnel
shaped hoppers, whence they may from time to time be removed by opening the
slides or drawers with which these funnels are provided. If desired in certain
cases the partitions within this separating chamber may be dispensed with.
From the last division of the separating chamber the air, freed from the particles
it had carried along with it, passes into an outlet pipe, and thence is directed back
to the fan, which acts in this case as an exhaust and drives the air again by the
hollow axle into the rotating drum. Here the air current is charged anew with
the pulverized material, which it deposits likewise in the separating chamber.
This contrivance permits of the separation from a given quantity of pulverized
material particles of any degree of fineness desired by regulating the speed of the
air current produced by the fan.
In order to prevent the obstruction of the holes in the one half of the axle
these holes may be protected by guard plates or funnels, or by any other con-
venient means.
It will be obvious that in addition to this dust blowing process the actual
grinding or pulverizing of the material can be effected in the drum by placing in
the latter balls of more or less weight. The drum is provided with suitable con-
trivances for charging it with the material to be treated, and for discharging the
same when desired.
It is evident also that this system is applicable to grinding apparatus of various
construction, as, for instance, disintegrators and corn mills, which permit of the
establishment of the above described circulation of air by means of a fan or other
blast contrivance.
It must be observed that the closed circulation of air, as above described, is not
indispensable, since the air if desired can be let out of the separating chamber and
fresh air introduced into the fan or blower.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Arthur William Lovell Reddie in the Great Seal Patent Office on
the 22nd July 1881.
ARTHUR WILLIAM LOVELL REDDIE, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Patent Agent. "IMPROVEMENTS IN THE METHOD OF
AND APPARATUS FOR ASSORTING PULVERIZED MATERIALS." A communication
from abroad by Woldemar Kracht, of the Begitza Station of the Orel-Vitebsk
Railway, in the Empire of Russia.
The ordinary process of elutriation or water washing serves to separate from a
mass of hard material the pulverized parts which are deposited in layers corre-
sponding to their specific weight. This generally employed process is however open
to objection in certain cases, as, for instance, when water is not to be had in sufficient
quantity at the place where this process is carried on, or in case the quality of the
water is liable to alter the nature of the pulverized material. Besides, elutriation
is altogether inapplicable for soluble matters which must be separated by a very
complicated and costly process of sifting through sieves of different gauge.
Moreover, elutriation is inapplicable wherever the physical and chemical nature
of the pulverized matter is altered by the action of water, as is the case in the
manufacture of cement.
All these drawbacks are aggravated by the necessity for drying the material
after elutriation, causing not only a great loss of time, but also requiring considerable
space and expense for fuel.
By the present Invention the separation of pulverized hard materials is effected
according to their weight, dispensing with water or any other liquid, as well as
with sifting. This method, which may be conveniently called a dust-blowing
process, consists in the use of a current of air within a special apparatus, the
construction of which will be seen on reference to the accompanying Drawing.
A is a drum made of cast or wrought iron or some other suitable material fixed on
the hollow axle B, and slowly rotated together with it. This rotation may be effected
by any convenient means. The hollow axle B, perforated on its sides, is divided
midway of its length by a partition B¹ in such manner that the two halves can
only communicate by way of the inside of the drum A. One end of the axle B is
connected air tight with the pipe D leading from a fan C, or any other blast
apparatus for driving a current of air through the axle B into the drum A, wherein
the pulverized material is constantly in motion.
The air current upon entering the drum by the perforations in one half of the
axle B has a tendency towards the perforations in the other half of the axle,
carrying along with it the finest particles of the pulverized matter into the pipe D,
by which they are conveyed to a depositing and assorting chamber E, consisting
preferably of several compartments separated by partitions which alternately reach
to within a short distance of the top or bottom of this chamber, as shewn at e, e.
In passing round the ends of the partitions the air current on its way deposits
the particles of dust which it has carried out of the drum A according to their
gravity within the funnel shaped hoppers F, F, whence they may from time to
time be removed by opening the slides or drawers f with which these hoppers are
provided. If desired, in certain cases the partitions within this separating chamber
may be dispensed with.
From the last division of the separating chamber E the air freed from the
particles it had carried along with it passes into an outlet pipe D, and thence is
directed back to the fan or blower C, which acts in this case as an exhaust, and
drives the air again by the hollow axle B into the rotating drum A. Here the air

page_text: current is charged anew with the pulverized material which it deposits likewise in
the assorting chamber E.
This contrivance permits of the separation from a given quantity of pulverized
material particles of any degree of fineness desired, by regulating the speed of the
air current produced by the fan or blower.
In order to prevent the obstruction of the holes in the second. or inner half of
the axle B, these holes may be protected by guard plates or funnels b, b, as shewn
in the Drawing, or by any other convenient means.
It will be obvious that in addition to this dust-blowing process, the actual
grinding or pulverizing of the material can be effected in the drum A by placing
in the latter balls of more or less weight. The drum A is provided with suitable
contrivances for charging it with the material to be treated, and for discharging
the same therefrom. It is evident also that this system is applicable to grinding
apparatus of various construction, as, for instance, disintegrators and corn mills,
which permit of the establishment of above described circulation of air by means
of a fan or other blast contrivance.
It must be observed that the closed circulation of air, as above described, is not
indispensable, since the air, if desired, can be allowed to escape freely from the
assorting chamber E, and fresh air be drawn in by the fan or blower.
Having now set forth the nature of the said Invention of "Improvements in
the Method of and Apparatus for Assorting Pulverized Materials," as communicated
to me by my foreign correspondent, and having explained in what manner the
same is to be carried into effect, I wish it to be understood that I claim,―
First. Assorting pulverized materials by agitating them in a chamber through
which a current of air is caused to pass, the dust-laden air being thence conducted
at a diminished speed through a second chamber wherein the pulverized particles
are deposited according to their specific gravity, all substantially as herein described
with reference to the Drawing.
Second. A drum or chamber rotating upon a hollow perforated and divided axle
in combination with a fan or blower and an assorting chamber, all arranged and
operating in the manner and for the purpose substantially as herein shewn and
described.
In witness whereof, I, the said Arthur William Lovell Reddie, have hereunto
set my hand and seal, the Twenty second day of July, in the year of our
Lord One thousand eight hundred and eighty one.