Hard Substances and Materials.
Year: 1887

page_text: Hard Substances and Materials.
I HENRY HOBSON of Ford Green House, Smallthorne, Stoke-on-Trent in the
County of Stafford Engineer do hereby declare the nature of this Invention to be as
follows:-
My said Invention relates to apparatus for pulverising or reducing minerals and
other hard substances and materials to fine powder and can be used either for the dry
or wet process of reduction. The apparatus constituting my invention consists of a
revolving drum having hollow axes communicating with the interior of the drum. To
lessen friction the said hollow axes are preferably supported upon antifriction rollers
which are carried by side frames or standards secured to the foundation, but I do not
confine myself to this mode of supporting the axes. A convenient mode of forming
the revolving drum is to cast the ends separately and fit an intervening ring or
periphery between the ends which may be flat but is preferably curvilinear in section.
The drum ends are formed with grooves or suitable fitting surfaces and the edges of the
ring are correspondingly formed so that when the ring is placed in position and the
ends of the drum firmly braced together with stays, bolts or other suitable means or
otherwise attached to the ring, a strong and secure joint is made between the ring and
the ends. The revolving drum thus constructed can be easily taken apart for inspection,
repairs or renewal. Within the drum I place a heavy crushing roller, bowl or ball,
the diameter of which may be approximately from one third to one half that of the
drum the periphery of the roller or bowl when such is used approximately corresponding
in shape or curve to the internal circumference of the drum. The periphery of the
crushing roller, bowl or ball and also the internal circumference of the ring are or
may be case hardened or chilled or composed of or lined or covered with a suitably
hard metal or alloy to resist wear. To give greater crushing weight to the roller, bowl
or ball I may form its periphery of a ring or sphere of chilled cast iron or hard metal
or alloy and fill in the interior of the roller, bowl or ball with lead or material of
greater specific gravity than cast iron, or instead of a solid roller, bowl or ball of the

page_text: indicated nature I might employ an annular ring running loosely in the revolving
drum. Any suitable means such as toothed or frictional gearing or a belt and pulley
may be used to rotate the drum. One of the hollow axles is connected by a conduit
or pipe with a settling chamber or with settling chambers and a current of air produced
by a fan or blower or other suitable air exhausting or forcing apparatus or arrange-
ment is caused to flow through the hollow axles and revolving drum carrying with it
the fine dust and powder produced by the pulverising operation the said powder being
deposited in the settling chamber. In operating with my invention the minerals or
other hard substances to be treated are first broken up to a suitable size if such
reduction should be necessary and are then thrown into the revolving drum through
the hollow axle or through a hopper which will deliver the material to the interior of
the drum. As the drum revolves the heavy crushing roller, bowl or ball contained
therein, rolls over and pulverises the materials. The finer particles rise in the form
of dust or fall from the upper part of the drum as it revolves and are carried
forward through the hollow axle toward the settling chamber or chambers by the
current of air produced in the manner herein set forth. The coarser portions are
carried round by the centrifugal action of the revolving drum and are again subjected
to the action of the crushing roller. This continuous carrying round of the
insufficiently reduced portions of the material under treatment prevents undue
accumulation behind the crushing roller, bowl or ball and to obtain this result it is
necessary to rotate the drum at such a speed as will carry the substance round by
centrifugal agency or so as to throw it in front of the roller or ball, while by varying
the speed, more or less of the material can be thus carried round as desired. By
regulating the force of the air current, which may be done by well known means,
powder of a greater or less degree of fineness can be drawn or forced from the
revolving drum. My apparatus is also applicable in the reduction of materials treated
with water in which case the outlet hollow axle would be of somewhat greater diameter
than the inlet so that the liquid carrying the finely reduced particles would overflow
into the outlet axle and pipe by which it would be conveyed to a suitable receptacle.
The drum would also be driven at a less speed and the crushing roller, bowl or ball
made somewhat less in bulk so as to allow the partially reduced inaterial to be again
washed or carried in front of the roller, bowl or ball. In treating materials by
the wet process it will be evident that no air exhausting or forcing apparatus is
required.
Dated this 11th day of November 1887.

page_text: Improvements in Apparatus for Pulverising Minerals and other
Hard Substances and Materials.
1 HENRY HOBSON of Ford Green House, Smallthorne, Stoke-on-Trent in the
County of Stafford, Engineer, 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 and accompanying drawings:
My said Invention relates to apparatus for pulverising or reducing minerals and
other hard substances and materials to fine powder and can be used either for the dry
or wet process of reduction. The apparatus constituting my invention consists of a
revolving drum having hollow axles communicating with the interior of the drum.
Within the drum I place a heavy crushing roller, bowl or ball, the diameter of which
may be approximately from one third to two thirds that of the internal diameter of
the drum. The periphery of the crushing roller, bowl or ball and also the internal
circumference of the drum are or may be case hardened or chilled or composed of or
lined or covered with a suitably hard metal or alloy to resist wear. Any suitable
means such as toothed or frictional gearing or a belt and pulley may be used to rotate
the drum. One of the hollow axles is connected by a conduit or pipe with a settling
chamber or with settling chambers and a current of air produced by a fan or blower
or other suitable air exhausting or forcing apparatus or arrangement is caused to flow
through the hollow axles and revolving drum carrying with it the fine dust and powder
produced by the pulverising operation the said powder being deposited in the settling
chamber. The minerals or substances are fed into the revolving drum through the
hollow axle or through a hopper which will deliver the material to the interior of the
drum. As the drum revolves the heavy crushing roller, bowl or ball contained therein,
rolls over and pulverises the materials. The finer particles rise in the form of dust or
fall from the upper part of the drum as it revolves and are carried forward through
the hollow axle toward the settling chamber or chambers by the current of air produced
in the manner herein set forth. The coarser portions are carried round by the
centrifugal action of the revolving drum and are again subjected to the action of the
crushing roller. My apparatus is also applicable in the reduction of materials treated
with water.
In order that my said invention may be properly understood I will now proceed
more particularly to describe the same with reference to the annexed three sheets of
drawings which are illustrative of my invention.
Fig. 1 on sheet 1 is a plan view of the general arrangement of my apparatus.
Fig. 2 sheet 2 is a vertical section of the apparatus. Fig. 3 shows the roller bearings.
Fig. 4 sheet 3 is a sectional view of a modification of the material and air inlet.
Referring to Fig. 2 of the drawings, the apparatus is shown to consist of a hollow
drum a having hollow axles a¹ a² mounted to revolve in bearings 6 which are preferably
fitted with anti-friction rollers c as shown by the separate view Fig. 3. The roller

page_text: b
g
bearings are supported on standards e which are firmly bolted to a sole plate f.
I might use bearings not provided with rollers. For the purpose of introducing the
grinding ball g I make one of the hollow axles a² removable and secure it to the
drum a by means of bolts as indicated in Fig. 2. The grinding roller or ball g is
made of a suitable size proportionate to the size of the drum say from one third to
two thirds of the internal diameter of the drum. The surface of the roller or ball
and the internal circumference of the drum are preferably case hardened, or chilled
or covered with a hard metal or substance which will resist too rapid wear. To increase
the weight and crushing effect of the grinding ball or roller g I might make it hollow
and fill it with lead or other material heavier than iron. I may rotate the drum by
any suitable means but as shown in the drawings a convenient mode is to turn or
prepare a portion i of the periphery of the drum g and drive the drum directly by
means of a belt passing partly around the prepared surface. Instead of a belt I
might form teeth on any part of the drum periphery or axles and drive it by means of
a toothed wheel or I might drive it by means of frictional contact with a revolving
disc. At the inlet side of the drum that is to say at the side marked A I connect a
conduit or pipe j and at the same side I attach the feed hopper k from which the
material is fed to the drum. At the outlet side of the drum that is to say at the side
marked B I attach another pipe or conduit ? which as shown at Fig. 1 forms a double
or breeched connection with a fan or blower m. The said fan is also connected by a
branch n with a settling chamber o which as shown in the drawings is divided into
two compartments. The delivery mouth of the branch n is fitted with a diverting
valve which can be set either to one side or to the other so that the powder drawn
from the drum a can be directed into either of the compartments of the settling
chamber at pleasure. Thus when one compartment has been filled the delivery can
be diverted into the other compartment while the filled compartment is being emptied.
The feed or inlet side of the drum a is also connected by the conduit ; to the settling
chamber. The fan or blower m is driven by belts passing over the pullies p from the
same shaft that drives the revolving drum or I might drive the fan directly from the
drum by frictional or toothed gearing or by belts or bands. The operation of my
improved apparatus is as follows. The mineral or other hard substances to be treated
are first broken up to a suitable size if such reduction should be necessary and are
then thrown into the hopper k from which the material is fed to the revolving drum a
in the manner shown at Fig. 2 of the drawings. The hopper is or may be fitted at
the foot with a delivery shaker or clack (see Fig. 4) for assisting the regular feeding
of the material to the drum. The fan being started simultaneously with the drum a
a current of air is set up through the drum a and through the conduits 1, n, and j
and into and from the settling chamber. As the drum revolves the heavy crushing
roller or ball g rolls over and pulverises the materials. The fine particles rise in the
form of dust or fall from the upper part of the drum as it revolves and are carried
forward through the hollow axle and through the fan towards the settling chamber o.
The coarser portions are carried round by the centrifugal action of the revolving drum
and are again subjected to the action of the crushing roller. This continuous centri-
fugal carrying round of the insufficiently reduced portions of the material under
treatment prevents undue accumulation behind the crushing roller bowl or ball and to
obtain this result it is necessary to rotate the drum at such a speed as will carry the
substance round by centrifugal agency or so as to throw it in front of the roller or
ball while by varying the speed more or less of the material can be thus carried round
as desired. By regulating the force of the air current, powder of a greater or less
degree of fineness can be drawn or forced from the revolving drum. The powder is
deposited in the settling chamber o on one side or the other of the partition o¹ and the
air which has carried it forward returns to the revolving drum through the conduit j
and thus circulates unceasingly. The settling chamber might consist of several
compartments suitable for grading the powder deposited therein, the coarser particles
being thrown down in the chamber nearest to the fan and the finer dust being carried
forward to the more remote chambers. Instead of having the delivery hopper and
the air inlet arranged as shown at Fig. 2 I might arrange them as shown at Fig. 4.

page_text: It is to be understood that although I consider the disposition of parts shown in the
annexed drawings to be a useful arrangement, I do not confine myself to this but
may vary the design according to circumstances, so long as the main feature of my
invention (namely the combination of means for feeding material to the drum, the
revolving drum and crushing roller, the air drawing or forcing apparatus and the
conduits and settling chamber) are preserved. I might also vary the shape and
construction of the hollow drum and of the crushing roller, bowl or ball. My
apparatus or a portion thereof is also applicable to the reduction of materials with
water, in which case the outlet hollow axle would be of somewhat greater diameter
than the inlet so that the liquid carrying the finely reduced particles would overflow
into the outlet axle and pipe by which it would be conveyed to suitable receptacles
for precipitation. In such a case the drum would be driven at a reduced speed and
the crushing roller, bowl or ball made somewhat less in bulk so as to allow the
partially reduced material to be again washed or carried in front of the roller bowl or
ball. In treating materials by the wet process it will be evident that no air exhausting
or forcing apparatus is required.
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) The general arrangement, construction and combination of apparatus for
pulverising minerals and other hard substances and materials substantially as herein-
before described and shown.
(2) In apparatus for pulverising minerals and other hard substances and materials
the revolving hollow cylinder containing a crushing roller, bowl or ball and having
hollow axles through one of which the material to be treated is fed from a hopper or
other receptacle while through the other the powder or dust is withdrawn by a current
of air set in motion by suitable air forcing or drawing apparatus and directed to a
settling chamber wherein the powder or dust is deposited the inlet axle of the drum
being also connected to the said settling chamber, all arranged and acting substantially
as herein before described and shown.
(3) The hereinbefore described revolving drum and contained crushing roller
applied to the reduction of minerals or hard substances in conjunction with water
substantially as described and indicated.
Dated this 10th day of August 1888.
DUTTON & FULTON,
1, St. James Square, Manchester,
Agents.