Note: Descriptions are shown in the official language in which they were submitted.
871
.,
BACKGROUND OF THE INVENTION
Heretofore it has been the general practice to dry
woods and other fibrous materials in a kiln or oven whereby
the moisture in the material undergoing treatment is first
converted into steam and thereafter the steam is removed.
In those processes wherein the outer surfaces of the materials
are dried first, any steam subsequently formed must pass through
this dried outer zone with resultant cracking and splintering
of the material. Additionally, in many woods, gums and resins
- 10 are destroyed if the process is conducted at elevated temperatures
~ thereby degrading the product or decreasing the market value thereof.
... .
SUMMARY OF THE INVENTION
It is therefore the primary object of ~e invention to
provide apparatus and aprocess for drying fibrous materials under
,J controlled conditiong, further including ~taining, finishing,
firepSoofing, laminating, forming, shaping and increasing the
tensile strength thereof.
Another object is to provide apparatus and a process
for drying fibrous materials including means to apply
; 20 mechanical pressure to the materials and also permit a source
of heat, steam, atmospheric pressure, dry air, vacuum and other
.,
` fluids to be applied to or removed from the ibrous material.
A final object is to provide a process for drying
... .
- woods wherein cracking and splintering is minimized and there
i is no degradation of the gums and resins in the wood.
. . .
The present invention is defined as a process for
.,,
treating wood comprisinq the steps of introducing the wood
`! into a closed chamber, applying a continuous mechanical force
.
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to at least one surface of the wood, applying a temperature
in the range of 70-200 Centigrade to the chamber, increasing
the atmospheric pressure within the chamber to 2-45 atmospheres,
reducing the atmospheric pressure within the chamber and removing
the moisturized air from the chamber, applying a vacuum to the
wood when the pressure in the chamber is at approximate room
pressure, and cooling the wood, releasing the vacuum, releasing
the mechanical force, and removing the wood from the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical sectional view taken along the
medial, longitudinal axis of a portable chamber of the
subject invention.
` FIG. 2 is a fragmentary, greatly enlarged, top plan
view of a plate utilized in the practice of the invention.
FIG. 3 iB a fragmentary, greatly enlarged, top plan
view of another embodiment of plate.
FIG. 4 is a fragmentary, greatly enlarged, top plan
view of still another embodiment of plate.
FIG. 5 is a vertical sectional view taken on the line
... .
5-5 of FIG. 4, looking in the direction of the arrows.
FIG. 6 is a greatly enlarged, vertical sectional view
through another embodiment of vertically adjustable, pressure
plate of the subject invention.
FIG. 7 is an end view, partly broken away and partly
in section, of another em~odiment of the subject invention.
FIG. 8 is a fragmentary, greatly enlarged, top plan
~ -
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view of another embodiment of plate utilized in the practice
of the invention.
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FIG. 9 is a vertical sectional view taken on the line
9-9 of FIG. 8, looking in the direction of the arrows.
FIG. 10 is a fragmentary, greatly enlarged, vertical-
sectional view of still another embodiment of plate of the subject
invention.
FIG. 11 is a fragmentary, perspective view, partly
broken away and partly in section, of means utilized for shaping
fibrous materials.
FIG. 12 is a fragmentary, perspective view showing
means for forming a design in a laminatea product.
FIG. 13 is a fragmentary, enlarged end view of a
laminated product with a design impressed in at least one surface
of the product.
, ,,
FIG. 14 is a fragmentary, enlarged end view of a
~ laminated product of the subject invention.
`' FIG. 15 is an end view, partly broken away and partly
in section, of a chamber utilized in shaping fibrous materials.
FIG. 16 is an end view, partly broken away and partly
5'' in section, of a chamber utilized in shaping and laminating
,:
~ 20 fibrous materials.
.
-~ DESCRIPTION OF PREFERRED EMBODIMENTS
, j,. .
- - Referring now to the drawings, wherein like reference
` characters designate like or corresponding parts throughout
the several views, there is shown in FIGS. 1-6 of the drawings
a portable, hermetically sealed, heat insulated chamber 20
,
of desired compositio~ shape and sizei door 21 is secured in
one end of said chamber in a fluid-tight seal and a second
i,
door 21a may in like manner be provided in the opposite end
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1~)1871
thereof to aid in loading and unloading. Viewing ports 22 are
desirably provided in the side walls, ends or doors of said
chamber to allow the user to observe the contents therein;
insulation 23, such as is well known in the art, is normally
apE~lied exteriorly of the remainder of said chamber. Wheels
25 and/or eyes 25 are provided on said chamber whereby after
loading in a manner hereinafter to be described said chamber
may be rolled or lifted into position beneath a hydraulic press
P or other pressure applying means at a remote location.
Horizontally extending and vertically adjustable plate
26 is carried within said chamber, preferably in a tight fit
with respect to the opposing side walls and/or ends thereof;
piston 27, secured downwardly to said plate, is journaled in
- bushing 28 mounted in the upper portion of said chamber; the upper
end 29 of said piston extends at l~ast partially above said
chamber in all positions o~ plate 26. It is to be understood
, that the invention is not to be restricted solely to the use
of a single plate 26 but also includes a plurality of smaller
plates of desired plan view and size, each of which may be
activated by a separate piston, whereby only selected plates
and the corresponding portions of said chamber may be utilized
. . .
at any time. Furthermore, the undersurface of plate 26 or
the corresponding surfaces of said smaller plates may be
~; essentially flat or may be of any predetermined configuration
,~ whereby wood products may also be shaped during the treating
:.
process. Still further, vertically and transversely extending
.,~ closure m~s (not shown) may be provided interiorly of said
i~
; chamber to form a plurality of smaller chambers which accommodate
::,
said smaller plates and preferably are to be used when only a
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limited number of pieces of wood are to be treated at one time.
Plate 30 of metallic composition includes a flat surface
31 adapted to be supported upon the bottom of said chamber.
As best seen in FIG. 2 of the drawings, the opposite surface
of said plate includes a plurality of integrally formed,
truncated pyramidal projections 32 each of which terminates
upwardly in a flat 33 lying in the same horizontal plane.
It is understood that projections 32 may be provided in any
regular or irregular pattern on said plate and the space between
adjacent projections, indicated generally by reference numeral
34, permits free circulation of fluids to a piece of wood or the
like supported thereon. One or more heating elements 35 such as
electric coils, high frequency thermal elements, heated water
conduits or the like are conventionally applied to each plate
in such a manner as to provide a controlled, uniform distribution
of heat.
Still referring to FIG. 1 of the drawings, a pre-cut
; piece of wood W of any desired shape and size is placed upon
.: ,
flats 33 of plate 30. For purposes of convenience only, a single
piece of wood is illustrated; it is understood that any desired
number of pieces, or rows, may be placed on said plate in like
~ manner. An opposing plate 30a, similar in construction to plate
-- 30, is inverted with downwardly depending projections 32a
bearing against the upper surface of said wood. Plate 26
is then lowered and adjusted to bear firmly against the flat
upper surface of plate 30a.
ij A plurality of apertures 36 in at least one side of
said chamber slightly above the bottom thereof, or in the bottom,
permit a source of hot air, steam, vacuum, or various chemical
.,,
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10~1~371
solutions to be introduced into or evacuated from the chamber thus
formed.
There is shown in FIG. 3 another embodiment of plate
30b wherein a plurality of integrally formed, truncated conical
projections 32b are diagonally aligned. Heating element 35
is conventionally secured to the upper surface of plate 30b
intermediate projections 32b.
In the modification of FIGS. 4 and 5, plate 30c
comprises sub-plates 37a-37b of similar construction, each of
which includes a plurality of vertically aligned sockets 38a-
38b adapted to receive a sphere 39 wherein each sphere at least
partially extends outwardly of the surfaces of the opposing
sub-plates. -One or more heating elements 35 are carried between
'~ sub-plates 37a, 37b and said sub-plates secured together as
by rivets 40 passing therethrough and expanded, or ~y other
astening means. A piece of wood placed upon plate 30c is
su~ported by the upper portions of said spheres and fluids may
freely circulate therebelow.
It is understood that the lower:surface of plate
26a, substantially similar to plate 26 heretoore described,
includes a plurality of parallel channels 41a which extend in
one direction (see FIG. 6) and a plurality of interconnecting
- parallel channels 41b which are at approximate right angles
relative thereto with heating element 35 carried in said plate;
alternatively, said heating element may be carried on the upper
surface thereof, in a conventional manner. In~addition, the
upper surface of the bottom of said chamber may include a
plurality of interconnecting channels (not shown), in any
:;,
` regular or irregular pattern, with a heating element conventionally:
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10~1871
.
carried therein whereby a source of heat or fluids may be
applied to one or more pieces of wood supported thereon.
There is shown in FIGS. 7-10 of the drawings
another embodiment of the invention wherein hermetically sealed
chamber 42 of desired shape and size comprises base 43,
laterally spaced side walls 44a, and top wall 44b with
insulation 45 such as is well known in the art applied exteriorly
of such members; the insulated chamber thus formed is then -
inserted into or otherwise provided with an outer metallic
~i 10 casing 46 of conforming configuration. Door 47 is hingedly
.
secured to selected portions of casing 46 in a fluid-tight seal.
Viewing ports 48 are normally provided in-at least door 47 and
` a television camera may be placed in a selected portion of
said chamber whereby the materials undergoing treatment may
be viewed.
,
' Horizontally extending and vertically adjustable plate
49 of metallic composition is carried in said chamber. Hydraulic
s cylinder 50, se~ured to casing 46 or a supporting surface vertically
,~ ,
thereabove, includes a downwardly depending piston 51 which is
: . 20 journaled in bushing 52 conventionally mounted in at least top
wall 44b of said chamber; said piston is secured downwardly
~`; to plate 49.
As illustrated in FIG. 7, laterally spaced and
longitudinally extending parallel channels 53 in base 43
, . -
accommodate horizontally disposed, rectangular plates 54 co-
extensive in length therewith. One or more hydraulic cylinders
. ~ ,
`~ 55, carried in the lower portion of channels 53, are inter-
connected by means of hydraulic lines 56; piston 57 of each
~ cylinder 55 connects to the lower surface of plates 54 whereby
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.
said plates are vertically adjustable.
A car 58 upon which pre-cut pieces of wood are to
be loaded includes flat bed 5g of metallic composition with
laterally spaced bracket means 60 secured in recesses 61 in the
undersurface thereof; wheels 62, adapted to ride on plates
54 heretofore mentioned, are mounted on said brackets. When
plates 54 are in elevated condition, car 58 may be rolled
into the chamber; upon lowering said plates, the lower surface
of bed 59 is uniformly supported on base 43.
As will hereinafter be more fully described, any
desired number of rows of pre-cut wood W may be placed upon
bed 59 with the pieces in each row in side-by-side relationship
and slightly spaced while each row is placed at right angles
relative to an adjacent row. Furthermore, one or moxe plates
63 of substantially similar construction and preferably smaller
in length and width, respectively, than the corresponding
' dimensions of plate 49 and bed 59 are placed intermediate sel
,, .
selected rows of wood. More specifically, each plate 63 is of
, "
metallic composition and the upper surface includes a plurality
of parallel channels 64a ~see FIGS. 8-9) with a plurality of
interconnected parallel channels 64b approximately at right
; angles thereto. Channels 64c-64d, respectively, are in like
.:
manner provided in the lower surface of each plate. A heating
coil 65 or high frequency thermal element is conventionally
applied to each plate with conductor 66 or the like detachably
;,
connected thereto externally of said plate.
~ In the modification of FIG. 10, the upper surface
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of plate 63a includes a plurality of parallel channels 67a
extending in one direction and interconnecting parallel channels
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~91871
67b extending at approxLmate right angles thereto; the lower
surface of said plate includes corresponding and vertically
aligned channels 67c-67d; channels 67a-67d are substantially
greater in width than channels 64a-64d heretofore described
in connection with FIGS. 8-9 of the drawings. An essentially
horizontally extending conduit 67e in plate 63a communicates
with lateral conduits 67f which surface in selected channels
67a-67d. One end of flexible tube 68 or the like connects
to the end of conduit 67e whereby a fluid may be applied to or
removed from pieces of wood supported on or adjacent said
plates 63a. A still further modified plate (not shown)
includes a plurality of vertically extending borss of any -
desired diameter and arranged in any regular or irregular pattern,
said bores passing completely through said plate and communicating
with a larger conduit throNghwh~,fiuids may pass.
Referring again to FIG. 7 of the drawings, conductors
66 heretofore mentioned connect remotely to each of said plates
63, said conductors may be passed through side walls 44a or
inserted into a socket (not shown) with a power supply ~'-
electrically connected thereto. Vacuum pump 69, at any remote
location, connects to said chamber by means of pipe 70 with
valve 71 fitted therein. Pipe 72, connecting remotely to a
source of hot air, steam, chemicals or the like, carries valve
73 and connects to said chamber. Desirably a vacuum gauge
74 and gauge 75 of a probe thermometer or the like a,re placed
at any desired location and communicate with said chamber;
probe 76 of said thermometer is adapted to be inserted into a
bore in a,selected piece of wood.
Referr~ng now to FIG. 11 of the drawings, there is
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871
shown coacting metallic plates 77-78 of desired size which are
used to form or shape fibrous material 79 therebetween in
accordance with the princip]es of the subject invention. More
specifically, inner surfaces 77a-78a of said plates may be of
any regular or irregular configuration; base 77b-78b of each
plate is flat and desirably includes a plurality of parallel
channels 77c-78c extending in one direction and interconnecting
parallel channels 77d-78d extending at approximate right
angles thereto. A plurality of vertically extending bores
10 77e-78e, in any pattern or arrangement, terminate in surfaces
77a-78a, respectively, and communicate with at least one
of said channels in the corresponding base.
Plates 77-78, with wood or other ibrous material 79
of desired dimensions therebetween, may be used in ch~mbers
20, 42 or the like for the process o the subject invention.
It is to be understood that although an elongated corrugated
pxoduct is illustrated in FIG. 11, the invention is not to
~r be restricted solely to such configured product but also covers
any other shaped fibrous product in accordance with the
prinGiples of the invention.
There is shown in FIGS. 12-14 of the drawings coacting
i~ plates 80-81 used to laminate sheets of wood or other fibrous
material 82 therebetween, and more particularly, to laminate
a plurality of sheets of fibrous material with a selected design
or pa~tern in at least one outer surface thereof. Plate 80,
. ~ .
of any desired si~e and of metallic composition, includes base
80a and a relatively flat upper surface 80b; a plurality of
parallel channels 80c extending in a desired direction are
provided in said base; a plurality of interconnecting parallel
,. ..
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871
channels 80d extend at approximate right angles thereto. A
plurality of bores 80e, in any pa~ern or arrangement, terminate
upwardly in surface 80b and communicate downwardly with
at least one of said channels 80c, 80d.
Plate 81 includes a relatively flat surface 81a with
a plurality of depressions 8 1 b of any desired configuration and
depth therein. The opposing surface 81c of said plate is
normally flat. It is understood that for laminating fibrous
materials in excess of approximately one centimeter in thickness
surface 81c may be provided with a plurality of channels (not
shown) extending in any desired direction with vertical bores
terminating, respectively, in surface 81c and at least one of
said channels.
As best seen in FIG. 13 of the drawings, fibrous material
82 comprises a plurality of sheets ~2a with adhesive 82b inter-
mediate each sheet. Plate 81, with surface 81a extending down-
wardly, is placed in a desired position on said fibrous material.
Ater completing the process of the subject invention, sheets
82a are laminated together with the selected design or pattern
,
formed in the outer surface; specificaily, flat surface 81a
of plate 81 partially compresses the fibers in the outer sheet
, ~
and forms corresponding recessed portions 82c while depressions
; 81b in plate 81 form raised areas 82d on said finished product.
~,:
The laminated product 83 of FIG. 14 comprises a
plurality of sheets 83a of wood or other fibrous material with
a & esive 83b intermediate said sheets. A product of uniform
- thickness and flat outer surfaces may be formed by using the flat
^ surfaces 80b of two plates 80 or the like.
There is shown in FIG. 15 of the drawings means to form
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or shape a heavy timber 84 or the like in accordance with the
process of the subject invention. In general, chamber 85
of desired dimensions and adapted to be hermetically sealed
and heat insulated includes base 85a with surface 85b spaced
thereabove. Form 86, including flat base 86a and upper surface
86b of predetermined curvature, is positioned upon base 86a
of said chamber. A plurality of parallel channels 86c extending
in one direction are provided in base 86a; a ~lurality of
- vertical bores 86d, in any pattern or arrangement, terminate
upwardly in upper surface 86b and communicate downwardly with
.: a selected channel 86c.
Coacting movable form 87, including lower surface
87a of predetermined curvature and relatively flat upper surface
87b, is prouided with a plurality of vertical bores 87c, in
any pattern.or arrangement, which terminate downwardly in surface
87a and upwardly in surface 87b, respectively.
Hydraulic cylinders 88, conventionally secured to
selected portions of surface 85b of said chamber, include
p.ist~.ons 88a which connect downwardly to surface 87b of said
movable form. A vacuum pump (not shown) connects to said chamber
by means of pipe 89 with control valve 90 therein; a source of
: hot air, steam, chemicals or the like may be introduced into
chamber 85 by means of pipe 91 with valve 92 carried therein.
.~ Upon activating movable form 87, timber 84 is forced
. ~
downwardly against form 86; a mechanical force in the range of
..,
~ 5000 kilograms/square cPntimeter applied to said timber,
i, .
.~ in.co~ination.with the remaining steps of the-process, dries
~ said timber to such predetermined curvature.
. There is shown in FIG. 16 of the drawings means to form
. .
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1(~91871
laminated beams or the like wherein each selected portion may
be formed or shaped to a predetermined curvature. Chamber 93,
of desired size and adapted to be heat insulated and hermeti-
cally sealed, includes flat base 93a and surface 93b spaced there-
above. A laminated beam 94 is to be formed between lower and
upper flexible metallic plates 95-96. In general, a plurality
of hydraulic cylinders 97 are conventionally mounted in spaced
relation on base 93a; piston 97a of each cylinder pivotally
connects upwardly to a selected portion of lower plate 95. In
like manner, hydraulic cylinders 98 are mounted on surface 93b,
desirably intermediate cylinders 97 on said base, with pistons
98a pivotally connecting to selected portions of upper plate 96.
A plurality of vertically extending bores 95a-96a~ in any
pattern or arrangement, pass completely through plates 95-96,
respectively.
A vacuum pump ~not shown2 connects to chamber 93 by
means of pipe 99 with valve 100 carried therein; a source of hot
air, steam, chemicals or the like may be introduced into said
chamber by means of pipe 101 with valve 102 fitted therein.
~. 20 Prior to use, any desired number of sheets or boards
'~ of wood or other fibrous material, of any dimensions, are
~; placed between plates 95-96 with an epoxy or phenol resin inter-
mediate all abutting sides and ends of each such sheet or board,
- after which selected cylinders q7-q8 are activated to apply a
,
; predetermined force in the range of l-SQ00 kilograms/square
:.
centimeter to the corresponding portions of plates 95-96 and
shpae the fibrous materials therebetween, in accordance with
:,.
the principles of the invention.
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1~)91E~71
It is understood that beam 94 thus formed may be of
uniform thickness or a beam 103 having a flat base 104 may be
produced therefrom by cutting or trimming.
Selected portions of plates 77-78, 80-81, 86-87, and
95-96 may be provided with heating means similar to heating
elements 35 heretofore described or a plurality of interconnected
pipes or conduits (not shown) in any regular or irregular pattern,
whereby a source of heat or fluids may be applied thereto or
circulated therethrough. Still further, selected portions of
chambers 20, 42, 85 and 93 may be provided with heating means
such as electric coils, heated water conduits or high frequency
thermal elements or the like whereby said chambers may be uni-
formly heated to any desired temperature, either for preheating
said chambers or for primary or auxiliary use at any time during
the process. Additionally, rotatable plates (not shown) may be
provided whereby trapped particles of water or the like are
removed by centrifugal force. Each of the plates heretofore
descri~ed may also he vertically disposed or coacting and
;-~
vertically disposed pressure plates (not shown) may be used in
combination with such essentially horizontally extending plates
to provide mechanical pressures to all four sides of a timber
or the like.
~,
r The wood treating process of the subject invention
will now be discussed in detail; it is understood that hence-
.....
forth throughout the specification and claims the word
:; ,;
"treating", as applied to woods or other porous and fibrous
materials, is used in a generic sense and includes not only
drying but also staining, finishing, fireproofing, laminating,
forming, shaping and increasing the density or tensile strength
thereof. For purposes of convenience only, the wood treating
, ~, .
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.
1~91871
process of the subject invention will be described in connec-
tion with chamber 42 of FIG. 7; it is understood that similar
steps are utilized in connection with chambers 20, 85 and 93.
To expedite said treating process, an initial pre-
heat step of any desired duration may be utilized, either prior
to or after loading chamber 42. More specifically, "contact
heat", provided by heating means in plates 30-30c or plates
63-63a, may be applied to said wood. Either simultaneously
therewith, or alternatively, "atmospheric heat", such as hot
air, saturated hot air, steam or superheated steam, may be
~ applied to said wood, provided that no substantial air currents
; are created in the chamber which tend to dry out the external
wood fibers and hinder the subsequent removal or moisture.
During such pre-heat stage, if no mechanical pressure is applied
- to a selected piece of wood, the temperature within said wood
,''.~,
must not exceed 60 Centigrade or warping and cracking will
occur. If a pressure ranging from 1-5 kilograms/square centi-
meter is applied to said piece, the temperature ~ithin said
piece must not exceed 80 Centigrade.
After hermetically sealing chamber 42, valves 71,73
are closed. At this time, a vacuum in the order of .005-8~ mm,
Hg may be applied to said chamber for 3-120 minutes to remove
,. ..
excess moisturé from said wood.
A predetermined mechanical pressure within the range
of 1-150 kilograms/square centimeter is then applied to said
pieces of wood W by means of hydraulic cylinder 50. Mechanical
pressure in th~ range specified, in combination with the
remaining steps of the process hereinafter to be described,
prevents warping and minimizes the formation of cracks.
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1~)91871
Furthermore, after a predetermined pressure within the s~ecified range
is applied to said wood, plate 49 may then be secured in such position
whereby although the wood may initially shrink and pull away from said
plate any subsequent expansion of the wood is limited by said plate and a
finished product of desire and constant thickness is formed. Finally,
the application of a predetenmined higher pressure within said range advap-
tage~usly results in a substantial increase in the tensile strength of such
piece. In general, if a selected piece of wood is not to be fo~med or
shaped and no substantial increase in tensile strength is desired, a
pressure of approximately 5 kilograms/square centimeter is normally applied
to a piece of wood not exceeding 15 millimeters in thickness; a pressure of
ap~rcximately 15 kilograms/square centimeter is required to fonm or shape
pieces of wood ranging from 2-8 millimters in thickness~ When a pressure
of 15 kllogram~/s~uare centimeter is applied to a flat piece of wood having
an initial thickness of approximately 12 milli~eters, for example~ the
tensile strength is increased 30-40 per cent. Still further, pressures
from 120-150 kilograms/square centimeter are required for heavy timbers,
es~ecially to upgrade the quality of the w~od by increasing the tensile
strength thereof.
,,
- 2Q When the wcod or other fibrous material is of subst~ntial
; thickness or the structure is of such a nature as to resist the flow of
m3isture to the surface thereof, it is desirable to first convert the
moisture in said fibrous material into stean, It will ke appreciated that
if the outer surfaces of said material are permitted to dry first, said
, .,
;~ cuter surfaces will shrink thereby entrapping moisiNre in the inner
, ~.
'; portions of such material and the steam subsequently formed must pass
through said dry outer s~rfaces wqth resultant cracking, splintering and
other physical damage to the material.
''
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l~'g~871
In each of the embodiments of the process of the
subject invention, the wood or other material i9 dried from
the center outwardly; specifically, steam which is formed in
the center of said material is subsequently driven outwardly
under controlled conditions. To expedite the formation of
steam within the center of a selected piece of wood, a temper-
ature in the range of 70-200 Centigrade is applied to said
wood in said chamber; more specifically, a desired temperature,
in the range specified, is at least partially provided by
"contact heat", heretofore defined. In addition, "atmospheric
heat", heretofore defined, is admitted into chamber 42 by means
of valve 73 either prior to the application of said "contact
' heat", simultaneously therewith, or thereafter. The source of
"atmospheric heat" i& controlled and preferably regulated to
match the temperature of said "contact heat" whereby a uniform
temperatuxe is applied to all surfaces of said wood.
j Either simultaneously with such heating step or
.:
shortly thereafter, and before steam is formed in said wood,
the atmospheric pressure within the chamber is raised to 2-45
atmospheres; the "atmospheric pillow" thus formed, substantially
greater in pressure than the steam pressure within said piece,
~": .
not only prevents the entrapped steam from escaping but also
causes the pressure of the entrapped steam to equalize in each
such piece. - Furthermore, said "atmospheric pillow" preserves
the moisture in the outer surfaces of each piece whereby the
moist, warm and expanded surface wood fibers provide a path
through which the entrapped steam may pass~
Probe 76 or other instrumentation is utilized to
indicate the temperature within the central portion of a
, . .
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1~)91~71
.
selected piece of wood. In general, when thermometer 75
indicates a temperature in the range of 70-180 Centigrade,
dependent primarily upon the variety of wood, a source of heat,
swch as hot air, either dry or at least partially moisturized,
or steam, at a temperature approximately equal to the tempera-
ture of the wood in said chamber, is applied to said chamber
and the atmospheric pressure within said chamber simultaneously
reduced to facilitate the removal of expanded steam from the
~ center of each piece. Alternatively, a dehumidifier or the
:.
like may be connected to chamber 42 whereby the moisturized
air or steam withdrawn from the wood is removed from said
chamber. The mechanical pressure applied to said wood may be
increased at this stage, within the specified range, to increase
the tensile strength; additionally, the temperature applied to
- said wood may also be increased, within the range specified, to
speed up the process provided that such increased temperature
doQs not melt the resins, gums or "Farbkernstoff" or cause the
same to erupt from and mar the surfaces of said wood.
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The atmospheric pressure within said chamber is
gradually reduced, while maintaining said chamber at elevated
, .
temperature, until room pressure is reached at ~hich time valve
71 is opened and a vacuum in the order of .005-80 mm.Hg applied
to said chamber. Alternatively, a centrifugal force may be
applied to said fibrous material, during said vacuum step, to
remove any remaining low pressure steam from said wood.
All sources of heat applied to said wood and/or
chamber are then cut of and the chamber cooled, while maintaining
mechanical pressure on said wood; desirabl~ water or a coolant
such as is well known in the art is circulated through the walls
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of said chamber and/or plates thereof for a period of 2-60
minutes to aid in cooling said chamber and the materials
therein. The vacuum is then released, the wood further cooled
while still under mechanical pressure, after which all mech-
anical pressure applied to said wood is released and the wood
removed from said chamber.
Test results indicate that green wood having a
moisture content in excess of 80% can be reduced to less than
8% in periods ranging from 20-40 minutes in accordance with
such teaching; furthermore, the moisture level can be reduced
substantially below 8% if longer periods are employed.
It is understood that additional steps may also be
included in such treating process whereby staining, finishing,
preserving, fireproofing, laminating, forming or shaping, and
t incréa~ing the tensile strength of fibrous materials may con-
venièntly be accomplished An alcohol, oil or water base stain
may be applied to a piece of wood or other fibrous material either
prior to or after loading chamber 42. The moisture in an untreated
~ piece of wood aids the initial penetration of stain into said;~ 20 wood; after treating in the manner hereinafter described, such
stain is evenly distributed throughout the entire piece. For
example, a ~acuum in the order of .005-80 mm. Hg is applied to
said chamber to remove gases and air from said wood, and a
selected stain, in either li~uid or gaseous state, is introduced
into said chamber. Alternatively, said wood may be immersed in
~ a selected stain, either in chamber 42 or in an auxiliary
- chamber, and a vacuum in the order of .005-80 mm. Hg applied to
said chamber until all hubbling within said stain ceases, The
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1091871
2-45 atmospheres, said atmospheric pressure subsequently
reduced to room pressure, and the wood treated in accordance
with the remaining steps of the process
Still further, said staining step may take place
a~ter said wood is at least partially dried and after the
atmospheric pressure in said chamber is at approximate room
pressure. At such time a selected stain is applied to said
wood in chamber 42, either by flooding said chamber or inject-
ing said stain under pressure into said chamber, The atmos-
` lO pheric pressure is then increased to 2-45 atmospheres after
which any excess stain is removed from said chamber and a
vacuum in the order of .005-~0 mm. Hg applied to said chamber.
The stained wood is subsequently dried and removed from said
chamber.
In like manner, other chemical compositions in either
a solid, liquid or gaseous state, may be applied to a selected
fibrous material a$ter a vacuum step More particularly, a
., i
polyurethane, phenol, polyester, polyethylene, or epoxy, as
well as copper chrome arsenate and ammonium chloride may be
utilized. A$ter all air and trapped gases are removed by a
i vacuum step in the order of .005-80 mm. Hg, the selected
`; chemical composition is introduced into said chamber, or said
chamber may at least partially be flooded therewith and then
i drained after a prescribed period o$ time. The pressure
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within said chamber is then increased to 2-45 atmospheres
whereby said composition is evenly dispersed throughout the
'~ porous material; heat, at the curing temperature o$ said
? chemical composition, is then applied to said chamber.
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1091871
The staining step and one or more additional treating
steps heretofore described may take place simultaneously. For
example, a selected water base stain ranging from 1%-30~ by
weight, dependent upon the shade of color desired, with a phenol
resin ranging from 10%-50% by weight, may be added to water.
Chamber 42 may be flooded with said solution or said solution
may be injected therein, followed by the remaining steps of the
process heretofore described in detail.
Certain woods, although structurally sound, contain
acids or salts which depreciate the market value thereof. The
process of the su~ject invention permits washing of the wood
fibers of such woods to remove said acids or salts. More speci- -
~ fically, said woods are placed in sealed chamber 42 after which
,~ a vacuum in the order of .005-80 mm. Hg is applied to said
~;:
't chamber. Water or a liquid adapted to neutralize said acids
; or salts is then introduced into said chamber and the atmos-
pheric pressure in said chamber increased to 2-45 atmospheres;
the atmospheric pressure is then reduced to room pressure and
the water containing said acids or salts in solution, or said
other liquid, is removed from said chamber. These steps are
repeated for 1-60 minutes, dependent upon the fiber structure
and the chemical concentration, until all acids or salts are
removed or reduced to an acceptable level; said wood may then
'~ ~e dried or other~ise treated in accordance with the principles
of the subject invention.
As is well known in the art, the melting point of
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certain gums and resins, especially those found in exotic woods,
is in the order of 80-90 Centigrade. In treating these woods
. .~,
a mechanical pressure in the range heretofore specified is
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10~1~71
first applied to said wood in said chamber, followed by a
vacuum step ranging from .005-80 mm. Hg, dependent upon the
species of wood, the thickness and moisture content thereof,
for 3-150 minutes. A source of heat substantially below the
melting point of said gums and resins is then applied to said
wood by means of plates 30-30c or plates 63-63a whereby the
moisture in said wood is converted into steam at reduced
temperature with no degradation of the material.
During forming or shaping operations, after placing
the wood or other fibrous-material between the configured plates,
said chamber may be flooded with a chemical composition such as
ammonia or the like which advantageously softens the wood fibers
and makes the piece more flexible and adaptable for forming and
shaping. It is further understood that if the moisture content
within a selected piece of wood excees 3Q%-35%, said piece
cannot effectively be formed or shaped and the moisture content
~, must first be reduced to such upper limit, desirably by means
of a vacuum step in the ordsr of .005-80 mm. Hg. The applica-.~
tion of a mechanical forc~ in the order of 1-5000 kilogramc/
square centimeter in combination with decreasing the moisture
' content in accordance with the principles of the invention not
.... .
only forms said wood into the desired shape but also~ when
. dried, said product maintains such desired shape. Staining
' and impregnating steps, heretofore described in detail, may.
, simultaneously be conducted during such forming or shaping
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steps.
Laminated product 83 of FIG. 14 is formed using a
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`~i,, plurality of moistened sheets 83a with adhesive 83b, applied
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~V91871
as by spraying or brushing, intermediate said sheets; typical
adhesives include epoxy and phenol resins and commerci~lly
available concentrated resins such as LEIMHARZ-LMB-1107. In
one typical example of such laminated product 83, 125 grams of
a phenol resin per square meter is conventionally applied to
at least one surface of adjacent sheets. A mechanical pressure
of 18 kilograms/square centimeter is applied to two plates
similar to plate 80, with said unfinished product therebetween.
An atmospheric pressure of 3 atmospheres and a temperature of
138 Centigrade is applied to chamber 42 for 50 minutes, thereby
drying and simultaneously laminating sheets 83a together.
In preparing laminated beam 94 of FIG. 16, the
moisture content of each sheet or board desirably should not
exceed 30%-35%; below such limit the moistened wood fibers are
flexible and readily formed to a predetermined curvature.
~ter drying, in accordance with the principles of the invention,
beam 94 maintains such predetermined curYature
It should ~e understood, of course, that the fore-
. ,~
going disclosure relates to only preferred embodiments of the
invention and that it is intended to cover all changes and
modifications of the apparatus and process herein chosen for
r; the purposes of the disclosure which do not constitute
departures from the spirit and scope of the invention.
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