Improvements in Apparatus for Drying Wood, Cloth, and other materials.
Year: 1893

page_text: Date of Application, 28th Mar., 1893-Accepted, 13th-May, 1893
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drying Wood, Cloth, and other
materials.
We, LARS MAGNUS LARSSON, Ironwork Manager, Dejefors, near Deje, and
CARL JOHAN BERGSTRÖM, Engineer, Finshyttan, both in Sweden, 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 :-
This drying apparatus principally intended for drying sawn wood, fire-wood and
wood in general but also serviceable for drying other objects, as for instance cloths,
is arranged for drying by means of hot air and therefore provided with several
compartments, into which the objects to be dried are distributed and through which
the hot air is caused to circulate so long as it can absorb any humidity. The
compartments are arranged around a central compartment, in which the air is
heated and any compartment, one or more can be caused to communicate with the
said central compartment, while the others communicate one with another. The
communication between the compartments is further so disposed that the air gets
into the compartment at the top and escapes at the bottom, whereby is effected,
that the hot air is uniformly distributed in the compartment, and that the humid
air is removed from the point where it, owing to its gravity is gathering. This
communication between the compartments is effected partly by means of canals
existing between the compartments, partly by means of a main canal leading to a
condenser with which main canal each compartment can be caused to communicate
by opening a door. The draught is obtained by means of a fan which re-conducts
the air from the condensing compartment to the heating apparatus, whereby the
same air is maintained in a constant circulation.
On the annexed drawing Figures 1 and 2 are vertical and horizontal sections of
a larger drying apparatus of this kind and 3, 4 and 5 the same sections of a
smaller one.
The same consists of the central compartment A where a heating apparatus of
some kind is mounted. The compartments arranged in a circle around the central
compartment and numbered 1-8 are the drying compartments excepting the last,
being the condensing room. Those compartments being sufficiently deep radially
as to contain boards etc. are at the circumference separated by triangular inter-
spaces B, serving as air canals. Near the roof the central compartment is provided
with doors leading to the store rooms, one for each compartment, those doors being
in Fig. 1 numbered in the same way as the compartments. Further each canal B
communicates at the bottom though an opening in the one side wall with the one
adjacent store room and through an opening at the top on the other side wall with
the other adjacent store-room. The former openings have doors a to be opened or
shut by heaving up or letting down, as shown Fig. 1, and to the latter openings
corresponds the triangle bed Fig. 1. The central compartment is at the bottom
surrounded with a canal k which always communicates with the condensing
compartment and to which a door 6' at the bottom in each store room can be
opened. From the condenser the air passes over the screen a¹ to the fan F, which
conducts the same to the central compartment. Of the two triangular compart-
ments between the compartments No. 1 and No. 7 only one is used as an air canal,
and the other can be used as store-room. Over the condensing compartment goes a
canal B', through which the said air canal communicates with the next store room.
The drying apparatus is used in this way. Supposing all compartments are
filled excepting for instance No. 7, where wood is laid in or taken out, and that

page_text: No. 1 is the compartment into which the hot air is first let in for achieving the
drying. The door No. 1 above the heating apparatus is then left open, so that the
hot air can get into the compartment No. 1. The hot air sinks through the mass
of wood and escapes through the opening a. The air gets now into the canal B
where it ascends in order to get into the compartment No. 2 through the upper
opening of the same canal. In this way the air passes through all the compart-
ments until it gets into the compartment No. 6. In this compartment the door a is
closed but the door open so that the air, now saturated with moisture can get
into the canal K and further into the condensing compartment. Arrived into the
condensing compartment the water absorbed by the air during its passage through
the wood is removed, the air passing further through the fan into the heating com-
partment and so through the apparatus once more in a constant circulation.
If the objects to be dried are so moist that the air will be saturated with water
during its passage through for instance 3 compartments, the doors a and in the
third room are adjusted as stated above with respect to the compartment No. 7,
so that the said compartments will form one division. In the same way other com-
partments can form another division, into which the air can get in through the
respective door above the heating apparatus. Likewise such a division can consist
of only two or one compartment, whereby it will be possible to have many
separate divisions at the time. The drying can thus be carried on at will in each
division, a greater or lesser part of the drying apparatus can be used as occasion
requires and by using the whole drying apparatus, great quantities can be dried at
a time within a comparatively small space. If the moist air is let out in the open,
it is evident that no compartment is wanted for the condensation.
If the drying compartments are arranged in a circle, as in Fig. 2, the radius of
the circle cannot be taken smaller, the central compartment deducted, than that
the compartment will radially have sufficient size to contain boards etc. The
number of the compartments can then however possibly be greater than wanted.
Figs. 3-5 represent therefore another mode of distributing the drying apparatus,
if wanted to have less numerous but nevertheless sufficiently large store-rooms
with appertaining canals. The same can therefore be rectangular and be divided
into four corner compartments and one central compartment, and canals can be
located partly outside between the drying compartments partly at the outer sides
of the central compartment. If at the same time a condensing compartment is
wanted, this may be located at the one long side, as shown in Fig. 4. Every
drying compartment is, as already described provided at the top with an opening to
be closed leading into the central compartment. Under the bottom of the latter
there is further a compartment K¹ communicating with the condensing compart-
ment and corresponding to the first mentioned canal K with which compartment
the drying compartments can be caused to communicate by opening the respective
doors situated most downward at those sides of the drying compartments, which
are next to the compartment K¹.
The air canals communicate at the top and at the bottom with different com-
partments as above explained. The hot air being supposed to arrive first into the
compartment No. 4, its passage will be as follows;-down through the compartment
No. 4 through a canal under the fan compartment F into the air caual d up
through the canal d out into and down through the compartment No. 1, into the
canal d and so on, until it arrives into the compartment No. 3, the door of
which 2, Fig. 3, is open, so that the air can get through the compartment K¹ into
the condensing compartment. Under the store room a³, a canal goes from the
compartment No. 2 to the air canal d². By the preceding description it results
clearly that also at the arrangement of the drying apparatus shown in Figs. 3—5
a greater or lesser part of the latter can be used and likewise that it may be used
in two different divisions.
It is evident that at all openings wanted to be closed, valves regulated from
without in lieu of the said doors may be used.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is,
A drying apparatus for wood and such like characterized thereby, that the drying
compartments arranged around a central compartment, from which the hot air is
taken, communicate with each other successively through canals, that each
drying compartment at the top has a door or valve opening into the central
compartment, that under the drying compartments there is a canal or com-
partment (K) going out into the open or into a condensing compartment
communicating with the central compartment through a fan, and with which canal
or compartment (K) every drying compartment can be caused to communicate
by opening a door at the bottom, and that the canals connecting the drying
compartments can be closed by means of doors or valves, so that one drying
compartment is separated from the other, all with the view that part of the
drying compartments, of which the first communicates with the central compart-
inent and the last with the canal (K) may be caused to communicate one with
another in order to form a division used for drying, which division is traversed by
one and the same air current, and that the compartments in this division may
successively be exchanged against others by shutting up the first compartment
from the central compartment, causing the next compartment to communicate with
the central compartment and causing the last compartment to communicate with
a new compartment which is made communicating with the canal (K).
Dated this 28th day of March 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicants.