Improvements in Cell-cylinders for Drying Apparatus.
Year: 1898

page_text: Date of Application, 18th June, 1898-Accepted, 6th Aug., 1898
[Communicated from abroad by Messrs. MOLLER & PFEIFER, of 19, Friedrich
Wilhelmstrasse, Berlin, in the Empire of Germany.]
Improvements in Cell-cylinders for Drying Apparatus.
I, SAMUEL SIDNEY BROMHEAD, of 171, Queen Victoria Street, in the City and
County of London, Patent Agent (communication from abroad), 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:-
The present invention relates to the inner construction of rotary drying chambers
or drums through which the gases of combustion of a furnace are led, thus directly
effecting the dessication of the materials to be dried.
The drying chambers of this kind hitherto used were provided internally with
scoops or bent ledges, which lift the materials in the cylinder so as to make them
fall as often as possible through the gases of combustion. The chambers to which
the present invention refers are fitted with a number of cells of any preferred
section, said cells lining the whole length of the cylinder, and being so formed
that the materials to be dried are hindered from falling beyond their particular
cell.
I will now describe the invention with reference to the accompanying drawings
in which:
Fig. 1 shows a cylinder of this kind. The gases of combustion of a fire place p
are led longitudinally through the revolving cylinder o where they become laden
with moisture through contact with the materials to be dried, and are drawn off
through the flue q.
The damp materials are poured into the funnel d and fall on the mouths of
the cells, at the end of the cylinder, they distribute themselves into the cells and
then slowly progress through the same towards the outlet hopper r.
Figs. 2 and 3 show the cells disposed evenly across the section of the cylinder.
In Fig. 2 the cells are approximately rectangular, whereas in Fig. 3 they are
shown hexagonal in one part and in another part as oval.
The ring shows the means of isolating the heat in the cylinder.
C
Let it now be understood that by the above means the material to be dried has
been introduced equally into all the cells and the cylinder revolved in the direction
indicated by the arrows. The materials will distribute themselves in the cells,
in much the same way as shown in Figs.
and 3.
The particles of material will lie one above the other and will expose a very
extended surface to the hot gases. This extended surface and dispersion of
materials among all the cells is very important for quick drying.
In all former drying cylinders or drums, the hottest gases follow the upper
side of the cylinder.
In drums fitted with cells, as shown in Figs. 1, 2 and 3, the material to be
dried is lifted up to the upper side of the cylinder and remains there, exposed to

page_text: the action of the hottest gases, thus ensuring rapid drying. Other cylinders have
this disadvantage that the hot gases hardly touch the moist materials.
The metal sides of the cells further serve as heating surfaces upon which the
metal is warmed, and this is particularly advantageous as said heated metal walls
or sides warm those portions of the material which are not exposed to the direct
influence of the gases. The metal sides of the cells also serve to store heat, as
they absorb same when no moist material rests upon them, and lose same again
directly their surface is covered with said material. Besides this the walls of the
cells are only covered on one side with material and the heat circulates through
their entire area.
The disposition of the cells also causes the cylinder to be more evenly loaded
and this serves to greatly reduce the strength necessary for revolving same. The
cylinder requires to be much less often revolved than those constructed hitherto
as the object is only to turn the material within the cells and to expose new sur-
faces to the gases and again to heat the dried surfaces which have become cooled
through evaporation.
Another advantage of the division into cells, is that the material undergoes
very slight circular movement.
Fig. shows the path followed by a particle of material at each revolution
of a cylinder not fitted with cells, same path being indicated by the dotted line f.
This circular movement depends upon the angle at which the cylinder is inclined
and also upon the distance which the particle of material traverses.
In the same
figure the dotted line g shows the path followed by a particle of material confined
in a cell, at each revolution of the cylinder. It is thus possible to expose the
materials much longer to the action of the gases.
This division into cells and the principle upon which the drying operations are
conducted is adapted for all suitable materials but more especially for those which
have a tendency to clog or cake, such as very moist clay and similar materials.
The various portions of these materials will always remain separate when in the
cylinder and each will dry by itself.
Besides the above objects attained by the new mode of construction, the very
important improvement is made that the present invention allows of the drying in
cylinders, under the direct influence of the gases of combustion, of materials which
it was previously impossible or difficult to dry in cylinders. The size of the
particles being often very different in the same material and the large pieces being
always more difficult to dry than the small ones, it is advisable to provide the cells
with a series of openings b shown in Fig. 2, through which the smaller pieces
of material fall into the outer cells and move along the sides of the cylinder towards
the exit quicker than the larger pieces which are detained in the cells. The
important result is thereby attained that the fragments which are more quickly
dried leave the cylinder sooner than those which require more time.
It is also feasible to construct the cells of perforated, woven or expanded metal.
In order to obtain good results from the before explained principle, the cylinders
should be provided with suitable arrangements for equally distributing the
materials among the cells.
The new invention is therefore also characterised by special arrangements for
distributing the material among the cells in the whole of the cylinder. As above
mentioned the even filling of all the cells is obtained by the inside cells not coming
forward by rotation as quick as the exterior ones.
The ingress funnel d leads the material to the middle cells. These being able
to receive only a portion of said material, the surplus of same falls along the slope
of the cylinder into the outer cells.
Figs. 4 and 5 show a distributing apparatus so disposed that the outlet of the
funnel which is fixed sidewards on to the axle of the cylinder, passes in front of
the openings of the cells as same revolve.
Each cell being provided with a small scoop or shelf m or e, the material falls

page_text: directly from the funnel into the separate cells. The particles of material which
are not at once taken by the cells, fall to the bottom of the cylinder where they are
scooped up by the last row of cells m'.
Figs. 6 & 7 show another method of filling the cells. The material falls through
a funnel d into the cylinder and is at first only distributed among the outer cells
by whose scoops it is gathered up.
After a semi revolution however a portion of the material falls through suitable
openings in the inside cells k and from there to those indicated by b.
The reversed method of filling the cells is shown in Figs. 8 and 9; by this
method the material first reaches the inside cells b, then through the openings i, a
part of it passes on to the cells k and l.
Lastly Figs. 10 and 11 show a distributing arrangement which prevents the
scattering of the material. In this case the end of the cylinder is not cylindrical
but conical and is internally provided with slanting partitions or helical blades vv,
shown in Fig. 10.
In the case illustrated, the receiving ends of the cylinder is conical, and the
portion o of said cylinder is of tubular section. The sides of the parts of the
cylinder are fitted with helical blades. In portion of the cylinder radial
partitions divide same into 6 parts. The cells are filled by the material which
comes through d and is led by the blades 'e and distributed among said cells by
the partitions ¹l as shown in Fig. 11.
To avoid technical difficulties in the construction of the cells s¹ and sl, same
might be made of sheets of metal corrugated or rolled to any preferred section,
in the way shown in Fig. 3. The corrugated sheets should be soldered together
so that the top of the corrugations touch each other. These soldered sheets are
then pushed into the cylinder where they are secured.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1) A rotary drying cylinder through which the gases of combustion of a furnace
are passed, and in which cylinder a number of uniform cells of optional section are
fitted, said cells occupying the whole cylinder and being filled with the material
to be dried by suitable distributing arrangements, with the object of dispersing
said material throughout the cells of the cylinder and exposing a large surface
to the heated gases, and gradually causing same to progress towards the outlet,
as herein described and set forth.
2) In the drying cylinder specified in Claim 1, the arrangement of cells fitted
with holes for sifting the material, in order to retain the larger pieces thereof for
a longer period than the small ones, the latter being more quickly dried are allowed
to escape sooner than the former, as herein described and set forth.
3) In the drying cylinder specified in Claim 1, the method herein described
which allows the particles of material not taken up by the inner rows of cells to
fall to the bottom of the cylinder, and there be scooped up into the outer row of
cells, as herein described and set forth.
4) In the drying cylinder specified in Claim 1, the combination with cells of
scoops or shelves which pass in front of the outlet of the feeding funnel and thus
eventy receive and distribute the material to be dried, as shown in Figs. 4 and 5;
as herein described and set forth.
5) In the drying cylinder specified in Claim 1, the combination of distributing
holes or openings in the cells, to permit the material to pass from the cells into
which it is first fed on to other rows of cells, as shown in Figs. 6 to 9, as herein
described and set forth.
6) The application to the drying cylinder with conical end herein described,
of helical blades or conveyors and slanting partitions for leading the material to

page_text: be dried, into the cells, as shown in Figs. 10 and 11, as herein described and set
forth.
7) In a drying cylinder as specified, the construction of cells formed of corru-
gated metal sheets s which are fastened together in such a way that the convexities
of the folds in one sheet touch those of the adjoining sheet, thus forming cavities
which constitute cells, said corrugations to be of any preferred section
Said corrugated sheets to be placed inside the cylinder and secured.