Improved Method of and Apparatus for Drying and Seasoning Wood and Wooden Articles.
Year: 1896

page_text: Date of Application, 11th Apr., 1896-Accepted, 16th May, 1896
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Drying and Seasoning
Wood and Wooden Articles.
1, JOSEF POLKE, of 26 and 28 Kohlgasse, Vienna, in the Empire of Austria,
Manufacturer, do hereby declare the nature of my said invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
My invention relates to the art of drying or seasoning wood and has for its
object an improved method and apparatus for drying or seasoning wood and
wooden articles in a much shorter time than heretofore. According to the
methods now in practice, wood must be dried or seasoned very slowly, in order to
prevent its splitting or cracking. At present wood is dried and seasoned, as a rule,
in the open air, or in drying rooms by means of hot air, after having been seasoned
for a certain length of time in the open air. In the first case the drying and
seasoning process will require several years. By the latter-hot air treatment-
wood may be seasoned in several weeks, but the rapid shrinkage produced by all
known seasoning methods will in most cases cause a cracking of the wood thus
treated.
According to my improved method wood or wooden articles may be brought
to a state of perfect dryness and seasoning, even when still in a perfectly
green condition, in the comparatively short space of a few hours without any
cracking.
According to my improved method the wood is dried and seasoned by the
simultaneous influence of heat and pressure. The pressure applied to the wood is
so measured that it will just counteract the tensions produced in the wood by
the drying process, without, however, causing any compression of the wood.
In order to produce a compression of the wood and a deformation resulting
therefrom a much greater pressure would have to be applied than that which is
suited to my purpose.
The heat to which the wood is subjected may be supplied by steam, hot air or in
any other known manner, while the required pressure may be produced by weights
or by any other mechanical means.
The apparatus employed for carrying this improved method into practice must
necessarily vary according to the objects to be treated.
In the annexed drawings an apparatus is shown for drying and seasoning barrel
bcdies, and as a modification an apparatus for drying and seasoning lumber.
Fig. 1 shows the drying apparatus for barrel bodies in vertical section.
Fig. 2 is a side elevation of this apparatus.
Figs. 3 and 4 show in two vertical sections, on planes crossing each other at right
angles, the lumber drying apparatus.
In all figures similar letters of reference indicate like parts.
The apparatus shown in Figs. 1 and 2 consists of two metal forms, a bottom
one A', and a top one A, which latter inoves in guides D, D, while the former, A',
is stationary upon a platform P. These forms A, A', present on their inside the
shape of half a barrel body, and are provided with hollow walls, forming
chambers n, n to which steam, hot air or such like is supplied. This supply may
be effected in any desired or suitable manner; by way of example I have shown
a pipe d which conducts the steam to the bottom form A¹ through an inlet i, and
to the top form A through the inlet ; by means of a movable tube g which is

page_text: tightly guided in a stuffing box e, f, so as to permit the up and down movement of
the top form A. The lower form A' is enclosed in a sheet iron mantler and the
top form A in a similar mantle p which fits and slides over the mantle r. The
sheet iron mantles p and rare provided with apertures for the admission of air
which, entering below, becomes hented by the contact with the hot surface of the
form A¹, rises through the ducts & into the space between the two forins, where it
assists in drying the central part of the barrel body, and finally the air escapes
through the apertures of the upper mantle p. The top form A is weighted to the
suitable degree by the weights e and is suspended by a cross bar B and two vertical
bars D', D', so that it can be raised and lowered at will.
It a barrel body is to be dried, it is placed into the lower form A with one end
and the suitably weighted top form A is lowered down upon its other end, so that
it bears with its full weight upon the barrel body. Heat being applied at the
same time to the forms, a very rapid drying process takes place in the wood under
the simultaneous influence of pressure and heat. In the same measure as the wood
dries and consequently shrinks, the top form A slides over the barrel body and the
latter is thereby pressed into the lower form A'. In this manner the barrel body
is always tightly enclosed by the two forms, and a splitting or cracking of the
wood during this rapid drying process is thereby completely prevented. When
the top form A has quite or nearly, reached the lower form A', the seasoning and
shrinking process of the wood is completed. The harrel bodies thus treated will
now retain the form given to them and no subsequent cracking of the wood will
occur.
If temporary hoops are to be put on the barrel body during the described
seasoning process, this can be done in the well known manner by providing the
forms A, A on their inside with annular recesses , b, in which the hoops.
are placed and held in position while the forms close down upon the barrel
body.
The same apparatus may of course be employed for seasoning other suitable
finished or half finished wooden objects in the same manner, by substituting corre-
sponding forms for those shown in the drawing.
For drying and seasoning cut lumber, the apparatus must be somewhat modified,
as shown in Figures 3 and 4 of the drawing. This modified construction results
from the necessity of subjecting the lumber not only to a vertical, but also to a
lateral pressure to follow up the shrinkage, a circumferential pressure as in the
former case, being here impossible. In this apparatus, I 'employ a frame or
standard E, E for supporting the flat heaters F, which are provided with the
hollow spaces or chambers n, l. The pieces of lumber S which are to be seasoned
are placed on top of each other against the side of the flat heaters F, and against
their other side are placed the counter plates L. These counter plates L may also
be heatable, but by preference I provide them only with ribs m, m which rest
against the wood and thus form ducts or channels, through which hot air may be
passed, and which serve for permitting the water to run off which issues from the
wood during the drying and pressing process. By preference I construct the
apparatus, as shown in the drawing, for receiving two sets of lumber that is to say
with two uprights E, two heaters F and two counter plates L. The inner surfaces
of the counter plates L which are facing each other I form inclined, so that they
converge towards the bottom, forming a wedge shaped space. Into this space is
introduced a wedge K, which is pressed downward by a weight C, while a
weighted bar or follower C', which fits into the space between the heater F and
the counter plate L presses upon the lumber from the top. From this disposition
it results that the wood is under a constant pressure in those two directions in
which a cracking or splitting could occur during the drying process, and this
pressure follows up the reduction of the dimensions of the wood which is caused by
its shrinkage.
The lumber having been placed in the apparatus and the wedge and bars or
followers adjusted, steam or hot air is admitted into the heaters through the

page_text: pipes t, and the lumber, thus subjected to the simultaneous influence of heat and
constant pressure, will be dried and seasoned in the comparatively short time of a
few hours without any cracking or splitting occurring.
For obvious practical reasons I prefer to construct the apparatus for receiving
two sheets of lumber as shown, but the apparatus may, of course, be also made
single, for one set of lumber, in which case one side of the upright E is made
inclined, for the wedge K to bear against. The required pressure upon the wedge
and upon the followers may also be produced by any other known means instead of
by weights, as shown.
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. Improved method for quickly drying and seasoning wood and wooden articles
without their cracking or splitting, consisting in subjecting the wood to the
influence of heat and in simultaneously exerting a pressure upon the wood in such
directions and of just such force that without any compression of the wood being
caused, the tensions in the wood produced by the heating and subsequent shrinkage
are counteracted; substantially as set forth.
2. For carrying into practice the herein described method for quickly drying
and seasoning wood, an apparatus for treating conical articles, consisting of two
hollow heaters or forms A, A', adapted to be heated, the interior of which forms
presents the shape and size of the finished article, in combination with means for
approaching said forms A, A¹ to each other with a force sufficient to counteract
the tensions produced in the wood by its shrinking, but not so great as to cause a
compression of the wood, substantially as described and shown.
3. In apparatus for carrying into practice the herein described method for
quickly drying and seasoning wood, the combination with two forms A, A' adapted
to receive the article to be treated of the hollow spaces n, n arranged in the walls
of the said forms A, A' and adapted to receive the heating medium, and of means
for approaching said forms A, A¹ to each other with a force sufficient to counteract
the tensions produced in the wood by its shrinking, but not so great as to cause a
compression of the wood; substantially as set forth.
4. In apparatus for carrying into practice the herein described method for
quickly drying and seasoning wood, the combination with two forms (A, A')
provided with the ducts or passages h and adapted to receive the article to be
treated, of the hollow spaces n, n arranged in the walls of the said forms (A, A')
and adapted to receive the heating medium, of two hollow mantles p and r provided
with draft apertures and enclosing the said forms A, A¹ so as to permit their
moving towards each other, and of means for approaching said forms A, A' to
each other with a force sufficient to counteract the tensions produced in the wood
by its shrinking, but not so great as to cause a compression of the wood;
substantially as set forth.
5. For carrying into practice the herein described method for quickly drying
and seasoning wood, a modified apparatus for treating cut lumber, consisting of an
upright (E) a heater (F) adapted to be heated from the inside, a second heater or
counterplate L adapted to be pressed sideways against the lumber resting against
the heater F, and of means for exerting a pressure upon the lumber at right angles
to the pressure exerted by the part L, substantially as set forth.
6. In apparatus for treating cut lumber according to the hereindescribed method,
the combination with an upright E of a heater F, a counterplate or heater L
having an inclined surface adapted to form a converging space with another surface
in the apparatus, of a wedge K adapted to be forced into the space thus formed for
exerting a lateral pressure upon the lumber, and of a follower or bar C adapted to
exert a vertical pressure upon the lumber, substantially as set forth.
7. In apparatus for treating lumber according to the hereindescribed method,
the combination with an upright E of a heater F, a counter plate or heater L

page_text: provided on one side with ribs m adapted to form ducts or channels when resting
against the wood to be treated and having its other side inclined adapted to form a
converging space with another surface in the apparatus, of a wedge K adapted to
be forced into the space thus formed for exerting a lateral pressure upon the
lumber and of means for exerting a vertical pressure upon the lumber, substantially
as described and shown in the drawing.
Dated the 11th day of April 1896.
PHILIP M. JUSTICE,
Chartered Patent Agent, London,
For the Applicant.