Improved Method of and Apparatus for Drying and Seasoning Wood and the like.
Year: 1894

page_text: Date of Application, 19th Mar., 1894-Accepted, 9th June, 1894
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Drying and Seasoning Wood
and the like.
I, HERMANN C. ZAPPERT, of 3124 Lemp Avenue, St. Louis, Mexico, in the
United States of America, Manufacturer, 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 method hereinafter described, as well as the device for carrying that method
into effect, is intended chiefly for drying wood and is characterized mainly by
leading a current of air of a tension or pressure lower than that of the atmosphere
over the wood, for the purpose of quickly drying the latter also in its inner parts.
This drying may be effected not only by means of the draught of the air, but also
with the aid of dry or noist heat, and two or all of these means may be combined,
just as necessary for the sort and condition of the wood to be dried."
The kiln employed by me has generally several divisions, and I may treat two or
more of them differently at a time, or one division may be treated differently at
consecutive times. I prefer to combine the kiln with a balance for enabling the
operator to constantly determine and control the degree of dryness of the wood by
the weight of the latter. This possibility as well as the other ones above mentioned,
are of highest importance for the practical execution of my method, as will be more
fully described hereinafter.
A kilo with but one division is shown in Fig. 1 in a horizontal section, this mode
of construction being best adapted to reveal the principle of my invention. The
kiln proper a, within which are piled the blocks b of wood is connected at one side
by pipe e with the air-heater d containing a steam-coil e, and at the other side by
pipe with the exhauster g. Pipe c aforementioned has a slide or an equivalent
device c'.
This kiln is employed in the following manner:
Slide c is completely opened, and air is sucked through the drying-chamber a,
or through and around the wood b respectively, which air is slightly warmed by
washing the coil-pipe e. The free section of channel c is narrowed then by pushing
the slide a short way inwards, so that a certain degree of rarefaction arises within
kiln a, as the velocity of rotation of exhauster g remains unaltered. I then let more
steam pass through coil e, so that the air flowing through chamber d and into
chamber a is heated to a correspondingly higher degree.
In consequence of the pressure of the air within the wood being higher than that
of the air surrounding the wood, that former air will escape, together with the
moistness contained within the said wood, this moistness being turned into steam or
vapour by the heat of the drying-air. That is to say, that moistness escapes partly
as such, partly as steam or vapour, to the outer surface of the hot blocks of wood,
and is evaporated then completely, and led away, by the stream of hot air constantly
flowing through the kiln..
There is thus effected an equal and simultaneous drying of the wood throughout
its whole section, which cannot be attained by the employment of air of atmospheric
pressure, especially if a strong draught is used. In this latter case it may easily
happen, that warping of the wood occurs, as the latter is drying far more quickly
at its outer portions than at its inner ones. The desired effect could also not be
attained, if the drying-air would be rarefied, but not caused to draw, as then the

page_text: "
moisture escaping from the inner to the outer portions would entirely leave the
wood only in the course of a long, time; this rendering the process tedious, expensive
and practically nearly useless.
The principal mode of construction of my improved drying-apparatus is
represented in Figs. 2-9 of the accompanying drawings; Fig. 2 being a horizontal
section in line 10-11 of Fig. 6; Fig. 3 a vertical section in line 12-13 of Fig. 6
(seen from the right to the left); Fig. 4 a vertical section in line 14-15 of Fig. 2;
Fig. 5 a vertical section in line 16-17 of Fig. 6; Fig. 6 a vertical section in
line 18-19 of Fig. 2 (seen from the left to the right); Fig. 7 a detail later on to be
described; Fig 8 a horizontal section in line 20-21 of Fig. 4; & Fig. 9 a
horizontal section in line 22-23 of Fig. 4.
The air employed for drying the wood b, Figs. 2, 3 & 6,.that is piled up within
the chambers a', is heated in the oven d', Fig. 2, of any desired, construction, and is
led then through channel into the two parallel channels (Figs. 2 & 6);
channel is longer, and is conuected at and near its end with two channels of c
(Figs. 2 & 4), running parallel to channel *. The channels c-care put into
communication with their respective chambers by means of openings h, Fig. 5, all
or some of which may be partially or wholly closed by small slides h¹.
Similar channels (Figs. 2, 4 & 6) are arranged parallel to the
channels and c; said channels receive air through pipe k with slide k¹
(Fig. 2) and lead the same through suitable openings in their ceilings into the
chambers above them. Those openings may also be partially or wholly closed
by small slides, similar to the manner shown in Fig. 5 with regard to the parts /
and h¹.
Steam-coils are arranged within the channels i-3, for the purpose of heating
the air flowing through said channels, and also for moistening the same, as part of
the steam is allowed to escape into said channels. The steam is led to the coils
through pipe m, Fig. 7, and is led away by pipe m'. The inlet may be closed by
cock n,, so that any desired number of the several coils may be connected with,
or disconnected from respectively, the steam-pipe m. The outlet of the coils may
be, connected with the waste-pipe m', as well as directly with the channels con-
taining said steam-coils; that is to say, the steam may be (wholly or partly) led into
the air flowing through said channels, so that moist heat is conveyed by that air,
whilst dry heat is conveyed by the air coming from stove d'. The chambers con-
taining the wood may thus be provided with dry heat or with moist beat by the
mediation of the air flowing through them, just as required for the respective kind
and state of the wood. The air is also in this kiln sucked through the drying-
chambers proper by an exhauster g', Fig. 2, and is also kept on a tension lower
than that of the atmosphere, which is effected by means of the slides k¹ and k³,
Fig. 2.
Lengthwise below each of the drying chambers is arranged a channel o,
Figs. 2 & 6,.and o!, Fig. 4. These channels are reduced in the direction to their
onds, at which latter they are closed. Both the channels o and o¹ (the latter being
indicated by dotted lines in the right-hand part of Fig. 2) are brought into com-
munication with the exhauster g' by the pipes 92, Figs. 2, 8 & 9; these pipes
terminating into the widest part of said channels. The channels o and o' terminate
upwards into the drying chambers, that is to say, not in their whole breadth, but
by means of slits ppl which.contrary to said channels are reduced from their ends
to their middle portion, so that the narrowest part of the slits p and pl is above the
widest part of the channels o and o'. The air sucked into the drying chambers
through the chanuels cand cor i and i¹, thus, leaves the drying chamber through
said slides p, and p', by the peculiar configuration of which latter the air is sucked
off in a perfectly equal degree throughout the whole length of the drying chambers,
80 that the action of the air in said chambers is the like in all divisions of the
latter.
As has previously been mentioned, the blocks of wood to be dried are piled up
in several heaps, which are separated by interstices. In order now to prevent

page_text: that the air does not flow through said interstices, but directly through the blocks
of wood, there are arranged within the chambers a suitable number of partition-
walls r, Fig. 2, consisting each of a number of parts connected by hinges, so that,
if necessary, the several portions of such a wall may be laid side by side or may
be extended across the chamber, as represented in either case in the left-hand
part in Fig. 2. There are, further, arranged within the chambers side-flaps s,
Fig. 3, and end-flaps s', Figs. 3 & 6, the size of which is so chosen, that their
edges lie close to the blocks of wood. The interstices existing between the several
piles of the broad channels formed by said interstices are thus closed by said flaps,
so that air cannot flow through said interstices, but is compelled to flow directly
through the piles, thus acting very intensely on each part of the latter.
The piles of wood are placed on truck-cars t, Figs. 2 & 6, which are running on
rails v.
The number of these pair of rails may be as desired, and is, as a matter
of course, dependent on the size of the kiln. The kiln shown in Fig. 2, contains
three pair of rails, two of them being short and extending cross-wise the left-hand
part of the kiln, whilst the third pair is long and extends lengthwise within the
right-hand part of the kiln. The short rails are arranged on the platform w (Fig. 6)
of a balance, which is held by the scale-beams a. The wood whilst being dried, is
constantly weighed, so that the degree of dryness may be determined by means of
the weight of the piles. The position of the scale-beam or beams may be
transferred to the hands of the scale in any desired manuer. The dial with the
hands are not shown in the drawing as these parts are well known everywhere.
Also the left-hand portion of the kiln is provided with rails. These are not. to
be seen, however, in Fig. 2, as the bottom of said portion is broken up to more
clearly show the channel o.
The slits p and p₁ aforementioned, through which the air laden with the
moisture removed from the wood is drawn by the exhauster g', may be closed.at
any desired place and in any desired extension by means of bricks that are simply
laid upon the floor containing the said slit or slits.
The intensity of action of the drying air may, thus be altered and regulated just
as necessary for the state of the wood in the several portions of the kiln,; that is
to say, one portion of the kiln, or of the drying chambers of the same respectively,
may be treated otherwise than another portion, according to the size and extension
of that part or parts of the slits p or p', which has or have remained uncovered.
I may thus direct the air through and around the piled wood not only by aid of
the partition-walls r and the flaps s and s', but also by means of the slots.p and p',
in that I cover one or more portions of the slot, as has previously been explained.
By covering or closing one or more portions of the slots, the air is hindered from
entering the same at these parts, and is compelled to flow to those parts of the
slots which have remained uncovered, so that by this means drafts of any desired
direction and intensity may be produced. I am thus enabled to treat several
chambers differently at a time or the several portions of one chamber differently
at a time, as well as at consecutive times, which in either case is performed by air,
the tension of which is lower than that of the atmosphere and which may convey
dry heat as well as moist heat, as has all been explained above.
Having now particularly described and ascertained the nature of this inven-
tion, and in what.manner the same is to be performed, I. declare that what I
claim is
1. The method of drying, consisting in exposing the material to be dried to a
draught of air, the tension of which is lower than that of the atmosphere, for the
purpose as described.
2. The method of drying, consisting in exposing the material to be dried.
simultaneously or consecutively to draughts of common or hot dry or moist air,
the tension of which is lower than that of the atmosphere, for the purpose as
described.
3. A drying-kiln combined with an exhauster, aspirator or the like adapted to.

page_text: draw air of a tension lower than that of the atmosphere through the kiln, for the
purpose as described.
4. A drying-kiln, combined with sources of common or hot dry or cold air, and
with an exhauster, aspirator or the like adapted to draw one or the other sort or
several sorts of said air through the kiln at a tension lower than that of the
atmosphere, for the purpose as described.
5. A drying kiln having several chambers combined with sources of common and
hot dry and moist air, and with an exhauster, aspirator or the like adapted to draw
one or the other sort or several sorts of said air simultaneously or consecutively
through one or more of said chambers at a tension lower than that of the
atmosphere, for the purpose as described.
6. A. drying-kiln having one or more chambers combined by channels with
sources of common and hot dry and moist air, and with an exhauster, aspirator or
the like adapted to draw one or the other sort or several sorts of said air
simultaneously or consecutively through said chamber or chambers, the inlets or
outlets, or inlets and outlets, of said channels being adapted to be partly or wholly
closed, for the purpose as described.
7. In a drying-kiln, the combination with the chamber or chambers of the same,
of a balance or balances connected with the floor or floors of said chamber or
chambers, for the purpose as described.
8. In a drying-kiln, the combination with the chamber or chambers of the same,
of a balance or balances, the scale or scales of which form the floor or floors of
said chamber or chambers, for the purpose as described.
9. In a drying-kiln, the combination with the chamber or chambers of the same,
of a balance or balances the scale or scales of which are adapted to receive cars
carrying the material to be dried, and to weigh the latter during the process of
drying, for the purpose as described.
10. In a drying-kiln, the combination with the chamber or chambers of the
same, of a steam-coil adapted to heat the drying-air, said coil being adapted to
let escape a part or the whole of the steam into said air, for the purpose as
described.
.
11. In a drying-kiln, the combination with the chamber or chambers of the
same, of a channel or channels connected with an exhauster, aspirator or the like,
said channel or channels terminating by slots into said chamber or chambers,
the several parts of said slot or slots having different diameter, for the purpose as
described.
12. In a drying-kiln, the combination with the chamber or chambers of the
same, of a channel or channels having different diameter at different parts, said
channel or channels terminating by slots into said chamber or chambers the
several parts of said slots having different diameter, the smaller diameter of said
slots being at the wider diameter of said channels, and vice versa, for the purpose as
described.
13. In a drying-kiln, the combination with one or more chambers a', of parallel
channels adapted to lead hot dry air into said chambers, and of channels i
adapted to lead hot moist air into said chambers, the outlets of said channels
having slides adapted to close said outlets wholly or partly, substantially as
described.
14. In a drying-kiln, the combination with channels cc adapted to lead dry
hot air into the chamber or chambers of the kiln, and with channels i adapted to
lead moist hot air into the chamber or chambers of the kiln, of flaps & s' adapted
to close the intermediate spaces between the piles of wood or the like to be dried;
said flaps being adapted to compel the air to flow through said piles, substantially
as described.
adapted to lead dry
15. In a drying-kiln, the combination with channels
hot air into the chamber or chambers of the kiln, and with channels i adapted to
lead moist hot air into the chamber or chambers of the kiln, of partition-walls r
adapted to divide the inner space of the kiln into two or more compartments, said

page_text: walls consisting of several parts connected by hinges, said parts being adapted to.
be laid side by side at the sides of the kiln, substantially as described.
16. In a drying-kiln, the combination and arrangement of parts, substantially as.
shown in Figs. 2-6.
D
."
201 1
1100
HERMANN C. ZAPPERT,
By Robert Deissler,
38, Alexander Strasse, Berlin, C., Germany, Agent for the Applicant..