Apparatus for Drying Pulverulent, Granular, or Fibrous Materials.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Apparatus for Drying Pulverulent, Granular, or Fibrous Materials.
I, EDUARD THEISEN, of 15 Werder Strasse Baden-Baden, in the Empire of
Germany, Engineer, do hereby declare the nature of this invention to be as
follows:-
In many industries, as for example in chemical works, breweries, distilleries,
sugar manufactories &c., there exist a number of waste or by-products of com-
paratively low value when in wet condition, the drying of which to increase their
value and facilitate their transport has hitherto entailed considerable expense in
the erection of extensive drying apparatus taking up a large amount of valuable
space, and in the expenditure of a large amount of fuel.
My present invention has for its object the construction of improved apparatus
whereby the drying of such products can be effected in a comparatively
inexpensive manner, and which while giving a large output, is of a very compact
nature so as to occupy only a comparatively small space.
It consists mainly in the employment of a revolving drum the outer surface of
which is heated in any suitable manner, while the material to be treated is fed on
to its interior surface in such a manner as to be spread by centrifugal action in a
uniform thin layer over the same, a series of scrapers or stirrers being provided
within the drum by means of which such layer of material is detached from the
drum at certain points, so as to be stirred up and delivered on to another part of
the drum. By this means the material, while being subjected to the heat trans-
mitted through the drum, so as to be effectually dried thereby owing to the
thinness of the layer, is at the same time made to travel from the one end of the
drum to the other where it is discharged.
The said apparatus may be constructed in various ways for carrying out this
mode of operating. Thus according to one arrangement I arrange within the
externally heated drum a concentric cylinder, which may either revolve with the
drum or in the contrary direction thereto, and which contains pipes or hollow
surfaces through which the combustion gases from the fire that heats the outer
surface of the drum are made to pass. The material to be dried is introduced
through a hopper into this cylinder and in travelling along it, comes in contact
with the beated pipes so as to be partially dried thereby. Arriving at the other
end, the material falls through lateral openings in the cylinder into the drum,
where it is caused by centrifugal action to be spread in a thin layer over the
surface of the drum and to be carried round thereby. At one point of the internal
circumference of the drum are arranged a series of stationary scrapers or stirring
devices that remove the layer of material from the drum at that point and cause
it to fall back a little in advance of its previous position so that by this means the
material is made to travel gradually along the drum, while it is subjected to the heat
transmitted through the latter, so that it eventually arrives at the other end of the
drum in a dried condition and is there removed by scoops or other suitable
means.
The scrapers or stirrers are held in a yielding manner by being mounted loose
upon an axis and provided with balance weights so that should the material offer

page_text: undue resistance to the action of the scrapers, the latter will yield and be then
brought by the balance weights back into their original position again. The
aqueous vapour given off from the material is drawn off from the drum by an
exhaust fan.
According to another modification, more particularly suitable for drying fibrous
materials, such as hay &c., the central cylinder, with heated pipes is dispensed
with, and the drum is in some cases made of perforated metal or wire gauze, so
that the hot combustion gases of the fire come to a certain extent directly in
contact with the material in the drum. In place of the before mentioned scrapers
are provided revolving stirring prongs, that remove the fibrous material from the
drum at one point and open it out and at the same time feed it forward in the
drum, at the discharge end of which it is separated from the periphery of the drum
by a stationary fork, and is delivered thereby into a discharge shoot. As in the
previous case the axis of the revolving stirring prongs is carried by arms mounted
on pivots and provided with balance weights, so that the arms with the stirrers can
yield when they meet with excessive resistance.
When the drum is made of wire gauze or perforated metal the lower part thereof
is partially surrounded by curved troughs which catch any small particles of the
material that may fall through the perforations and which communicate by a pipe
with an exhaust by means of which such particles are drawn off.
Dated this 6th day of August 1895.
Apparatus for Drying Pulverulent, Granular, or Fibrous Materials.
I, EDUARD THEISEN, of 15 Werder Strasse, Baden-Baden, in the Empire of
Germany, 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 :-
In many industries, as for example, in chemical works, breweries, distilleries,
sugar manufactories, &c. there exits a number of waste or by-products of com-
paratively low value when in wet condition, the drying of which to increase their
value and facilitate their transport has hitherto entailed considerable expense in
the erection of extensive drying apparatus taking up a large amount of valuable
space, and in the expenditure of a large amount of fuel.
My present invention has for its object the construction of improved apparatus
whereby the drying of such products can be effected in a comparatively inexpensive
manner, and which while giving a large output, is of a very compact nature so as
to occupy only a comparatively small space.
It consists mainly in the employment of a revolving drum the outer surface of
which is heated in any suitable manner, while the material to be treated is fed on
to its interior surface in such a manner as to be spread by centrifugal action in a
uniform thin layer over the same, a series of scrapers or stirrers being provided
within the drum by means of which such layer of material is detached from the
drum at certain points, so as to be stirred up and delivered on to another part of
the drum. By this means the material, while being subjected to the heat trans-
mitted through the drum so as to be effectually dried thereby owing to the thinness
of the layer, is at the same time made to travel from the one end of the drum to
the other, where it is discharged.
The said apparatus may be constructed in various ways for carrying out this
mode of operating. On the accompanying drawings are shewn two such
constructions.
. 1 .

page_text: Figure 1 shews a longitudinal section and Figure 2 a cross section of one
construction,
Figure 3 shews a part sectional plan of a modification,
Figures 4 and 5 show respectively a longitudinal section and cross section of the
second construction.
In the arrangement at Figures 1 and 2 a is a revolving cylinder containing
centrally a second cylinder b, which is extended beyond a at each end, the
extension c being closed while d is open, which extensions serve as the means of
support and rotation for the combined cylinders, being provided with a toothed
ring or other means for receiving motion from a motor. Through the central
drum passes a group of pipes e, the ends of which are enclosed by caps el e², of
which e communicates with a flue pipe f¹ leading from the flues of the heating
chamber surrounding the drum a so that the hot combustion gases from the
furnace h are made to pass through the pipe f, cap el and pipes e and escape
through cape and flue pipe g to the chimney. The material to be dried is introduced
into the extension e through a hopper i and passes thence through openings k into
the cylinder, where it is seized by projecting blades or scoops of such a form
as to be thrown thereby on to the group of tubes e and at the same time to be
propelled forward in falling through the interstices between the tubes; arrived at
the other end of the cylinder b, the material falls through lateral openings m into
the drun a, the speed of which is preferably such as to carry the material right
round with it by centrifugal action. As it travels round it is brought in contact
with a series of slightly inclined scrapers n which detach the material from the
surface of the drum and cause it in falling to advance in the direction from the
openings m towards the other end of the drum, while at the same time it is
effectually stirred up so that all particles of the material are repeatedly brought in
contact with the heated drum surface, and the disengagement of the vapour
generated by the evaporation of the moisture is greatly facilitated. The scrapers n
are held in a yielding manner against the drum surface, so as to avoid concussions
and unnecessary wear, by the following arrangement. They are attached to arms
loosely pivotted on a shaft o, and provided with a weighted tail p, which keeps the
scraper against the drum.
The shaft o is carried by a series of rings q surrounding the cylinder band
having rollers resting thereon so that the ring can turn round the cylinder, but
the rings and scrapers are maintained in the position shewn by a weighted arm s,
so that if the scrapers should be subject to undue frictional resistance by the layer
of material they will be depressed thereby and will regain their original position
on such resistance passing away, so that no jamming or crushing of the material
can occur.
When the dried material arrives at the left hand end of the drum, it is taken up
by scoops t which in revolving discharge it through openings u into an annular
collecting channel from one point of which it is discharged into a shoot.
The aqueous vapour disengaged from the material in the drum is drawn off by
an exhaust fan communicating with the exhaust passage w.
If desired, the tube group e, instead of revolving with the drum, can be made to
revolve independently in the contrary direction, in order to increase the movement
of the material entering the drum.
For this purpose the arrangement shewn at Figure 3 may be employed, in which
the drum a is rotated by a toothed ring and the cylinder b with the tube group e
is rotated in the contrary direction by means of a toothed ring 1³, the cylinder b
being in this case separate from the drum. The shaft o carrying the scrapers n is
in this case extended through the end of the drum a and carried by an external
support o' the annular plate a' which closes the end of a being of course separate
from the latter and held stationary.
When the nature of the material to be treated is such that it will not be
damaged by coming to a certain extent in direct contact with the combustion gases
from the fire, such as for drying grass, hay, &c., the above described arrangement

page_text: may be somewhat simplified by making the drum a of perforated metal or wire
gauze, and dispensing with the heating tube c and cylinder b. This arrangement
is shewn at Figures 4 and 5. The hay or other fibrous material is introduced
through the hopper i directly into the drum a which is of perforated metal and
which is mounted on an axis a carried by external supports and driven by a pulley
or chain wheels and pitch chain.
Upon the axis is mounted loose a hollow stationary shaft
from which
project arms = carrying a shaft 1, to which rotary motion is imparted in any
suitable manner such as by pitch wheels and chain 2 from the revolving shaft 2.
On the shaft 1 are fixed a series of radially projecting prongs 3 which in revolving
therewith pass in close contiguity to the inner surface of the drum a.
y
The hollow shaft also carries one or more weighted arms s, which tend to keep
the shaft 1 with its prongs 3 in the position shewn, but allow of these being more
or less depressed when they meet with undue resistance from the material on the
drum. By the above described means the material revolving with the drum will
be continually stirred up and loosened, and as the shaft I is arranged with a
certain inclination, as shewn at Figure 4, the action of the prongs 3 will also cause
the material to travel gradually from the inlet end of the drum to the discharge
At the latter end is arranged a stationary discharge shoot 4 suitably held by
a fixed plate 5, fiom which projects a bent arm 6 to the end of which is fixed a
fork 7 situated at the periphery of the drum in such a position, that as the material
is carried ound by the latter, the fork detaches it and causes it to drop into the
shoot 4.
end.
Trough-like receptacles 8 are provided round the lower part of the drum, into
which fall any small particles of the material that may fall through the perforations
of the drum. These troughs communicate with a pipe 9 the outer end of
which is connected to an exhaust by means of which all the said particles are
drawn off.
In either of the above arrangements the drum a may be either cylindrical with
horizontal or inclined axis or it may be conical and its surface may either be plain
or corrugated.
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. Apparatus for drying granular pulverulent or fibrous material, consisting of a
revolving drum the outer surface of which is subjected to heat, and into one end
of which the material to be treated is introduced so as to be spread by centrifugal
action in a thin layer over the inner surface thereof in order to have the moisture
evaporated therefrom, while at the same time the material is subject to the action
of stirring or scraping devices so arranged as to detach and stir up the material
and cause it to travel from the inlet to the outlet of the drun, where means are
provided for removing the dried material from the drum, substantially as
described.
2. In apparatus for drying granular pulverulent or fibrous material such as is
referred to in the first claim, the use of scrapers or stirring devices which are held
in a yielding manner by means of balance weights or equivalent means so as to
yield to undue resistance offered by the material, substantially as described.
3. In apparatus for drying granular pulverulent or fibrous substances such as is
referred to in the first claim, the use of a cylinder arranged centrally within the
drum, through which the material to be treated is made to travel before entering
the drum, and where it is subjected to a preliminary drying by means of pipes
supplied with steam or hot gases, substantially as described.
4., Apparatus for drying granular, pulverulent or fibrous substances, constructed
and operating as herein described with reference to Figures 1, 2 and 3 of the
accompanying drawings.

page_text: 5. Apparatus for drying granular, pulverulent or fibrous substances, constructed
and operating as herein described with reference to Figures 4 and 5 of the
accompanying drawings.
ABEL & IMRAY,
Agents for the Applicant.