IMPROVEMENTS IN TREATING AND PRESERVING WOOD OR TIMBER, AND IN APPARATUS THEREFOR
Year: 1878

page_text: LETTERS PATENT to Hugh Hardman, of Beaumont Street, Portland Place, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN TREATING
AND PRESERVING WOOD OR TIMBER, AND IN APPARATUS THEREFOR." A
communication from abroad by Thomas Alexander Dowling and John Hardman,
both of New York, in the United States of America.
PROVISIONAL SPECIFICATION left by the said Hugh Hardman at the Office
of the Commissioners of Patents on the 19th December 1878.
HUGH HARDMAN, of Beaumont Street, Portland Place, in the County of Middlesex.
"IMPROVEMENTS IN TREATING AND PRESERVING WOOD OR TIMBER, AND IN
APPARATUS THEREFOR." (A communication from abroad by Thomas Alexander
Dowling and John Hardman, both of New York, in the United States of America.)
The objects of this Invention, which relates to improvements in the method of
and apparatus for treating or seasoning wood or timber, are, to dry, preserve,
strengthen, and beautify all kinds of wood or timber, either in a green or more
mature state, and thoroughly to season it without cracking or warping it, and
render it incapable of decay from natural or other causes in a short time and by a
simple and inexpensive process.
These results are attained by effecting chemical changes in the fluids naturally
contained in the wood by treating it by the agency of heat and compressed air.
The apparatus in which the wood is treated by the above referred to seasoning
process is constructed preferably as a strong cylindrical chamber (of any appropriate
or desired strength and size), made of boiler iron of great tensile strength, and if of
any considerable length it may be made in two or more sections, suitably joined or
connected together. Its bottom is slightly lowered at one end to facilitate the
I Dia ᏩᏘ ]

page_text: running into and out of the chamber of loaded cars carrying the wood operated
upon, and to collect for easy drawing off any water of condensation that may come
from the wood and collect in the bottom of the chamber.
The seasoning or wood chamber is provided with dished end doors, which when
closed perform the same office as heads to an ordinary steam boiler. These doors
are constructed also of boiler iron, and are provided with flanges slotted at equal
spaces around the periphery, and are secured by nuts on bolts swung from flanges
rivetted to the seasoning chamber, and engaging with the slots of the door flange.
The bolts can be readily swung back upon the nuts being loosened to allow of the
doors being opened and closed as required. The closure of the doors may be
rendered air tight by a luting of pasteboard or leather packing. When loosened
the doors hang from hinges which are suspended from cross-head axles of overhead
trucks by screws which are operated or raised and lowered by hand wheels, but
prevented from twining by feathers, the wheels of the trucks running on tramways,
so that the doors can also be moved to the right or left and adjusted in position
with the chamber as desired.
The seasoning chamber is heated by radiators, which consist of a series of metal
pipes of good quality placed near together and to the inner periphery of the
chamber, to the form of which they are bent, the pipes being connected by right
and left couplings to main pipes placed lengthwise of the chamber, one on each side,
and placed directly above the rail track, which is rivetted to the chamber, and
upon which the said loaded cars rest whilst the wood is being operated upon. The
main pipes are supplied from the boiler by suitable connections. Each pipe is pro-
vided with a steam trap at the lower end of the chamber to permit of any water of
condensation escaping from the pipe.
The seasoning chamber is provided with a safety valve to relieve an over accumula-
tion of pressure should the operator neglect his duty; and with a thermometer by
which the temperature is determined with a view to regulation.
The chamber is also fitted with a pipe leading from a suitable air-pump or com-
presser, and the amount of pressure attained within the chamber is indicated by a
guage.
Three sets of cars are of advantage in using the apparatus, one set for the inside
carrying the wood being operated upon while another is being loaded to be operated
upon, and a third being unloaded, having been operated upon. They are provided
with movable half hoops bolted to cross pieces, and bent to clear the inner periphery
of the radiator-tubes.
The improved method of treatment by the use of the above described improved
apparatus is as follows:-
The loaded car of wood to be operated upon is run into the chamber, the end
doors of which are then tightly closed. The steam is then turned on to the
radiator-tubes, and the wood is heated to any desired degree, and for any desired
length of time, by the radiation of heat therefrom, the effect of which is to open the
pores of the wood and expel all the watery vapor therefrom, after which the steam
is turned off and cold air is forced by the compresser into the chamber until a
sufficient pressure is attained within it to close the pores of the wood and force
back thereinto all the resinous and other preserving agents naturally contained in
the wood, coagulating them, and pressing the wood into a more dense condition,
the watery particles being previously driven off allow of this and ensure the
preservation of the wood from future decay from any natural causes. The loaded
car of wood is then withdrawn from the chamber and the process or treatment
thereof is completed.
In order to discharge the vapor and water of condensation expelled from the
wood by the above described treatment from within the chamber in or during the
treatment of the wood and without lowering the pressure within the chamber, so
that the wood shall be prevented from cracking or opening at any part, there is
placed a condenser composed of a coil of pipe in a vessel of cold water, in connection

page_text: with the cock used for the above referred to drawing off, and a similar connection
may be made with a similar cock at the other end of the chamber. The vapor
contained in the chamber is then let into the coil by the cock or cocks and
condensed into liquid, and at the outlet end of the condensing coil is placed a
receiving trap which will discharge the liquid without lowering the pressure in the
chamber.
The result is that upon the completion of the above described improved process,
and when the wood is removed from the chamber, it is perfectly dry without a
crack or check in any part. The amount of liquid to be taken away from the wood
can be regulated by the heat and pressure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Hugh Hardman in the Great Seal Patent Office on the 19th June
1879.
sex.
HUGH HARDMAN, of Beaumont Street, Portland Place, in the County of Middle-
"IMPROVEMENTS IN TREATING AND PRESERVING WOOD OR TIMBER, AND IN
APPARATUS THEREFOR." (A communication from abroad by Thomas Alexander,
Dowling and John Hardman, both of New York, in the United States of America.)
The objects of this Invention, which relates to improvements in the method of
and apparatus for treating or seasoning wood or timber, are to dry, preserve,
strengthen, and beautify all kinds of wood or timber either in a green or more
mature state, and thoroughly to season it without cracking or warping it, and render
it incapable of decay from natural causes in a short time and by a simple and
inexpensive process.
These results are attained by, and the principle of the Invention consists in,
effecting chemical changes in the fluids naturally contained in the wood by treating
it to a process of vulcanizing by the agency of heat and compressed air.
This principle may be carried into practice in apparatus of various descriptions,
as hereinafter referred to, but in order to cause the Invention to be more readily
and distinctly understood I have annexed hereunto one Sheet of Drawings illus-
trative of one arrangement of apparatus in or by means of which the said principle
can be very advantageously carried into effect.
This arrangement of apparatus is illustrated in longitudinal section in Figure 1 of
the accompanying Drawings, and in cross section in Figure 2, Figure 3 being a front
or rear view. It is constructed with or comprises a strong cylindrical chamber 1 (of
any appropriate or desired strength and size) made of boiler-iron of great tensile
strength, and if of any considerable length it may be made in two or more sections
suitably joined or connected together, as at 2, Figure 1.
The bottom of the chamber is or may be slightly lowered at one end to facilitate
the running into or out of the chamber of loaded cars (hereinafter described) carrying
the wood whilst being operated upon, and to collect for casy drawing off any water
of condensation which may come from the wood and collect at the low end of the
chamber, as also hereinafter described.
The seasoning chamber 1 is provided with dished end doors 3, which when closed
perform the same office as heads to an ordinary steam-boiler. These doors are con-
structed also of boiler-iron, and are provided with flanges 4 slotted as at 5, Figure 2,
at equal spaces around the periphery, and are secured by nuts or bolts 6 swung from
flanges 7 rivetted outside the chamber 1 and engaging with the slots of the door
flange. The bolts 6 can be readily swung back upon the nuts thereof, being simply
loosened to allow of the doors being opened and closed as required. The closure of
the doors may be rendered air-tight by a luting of pasteboard or leather packing.
When loosened the doors hang from hinges 8 which are suspended from cross-
head axles of overhead trucks 9 by screws 22 which are operated or raised and
lowered by hand-wheels 10, but they are prevented from turning by feathers thereon,
the wheels of the trucks running on tramways 39 so that the doors can also be
moved to the right or left and adjusted in position with the chamber as desired, as
shewn most clearly in Figure 3.
The chamber 1 is heated by radiators 11 which consist of a series of metal pipes
of good quality placed near together and to the inner periphery of the chamber 1, to
the form of which they are bent, as shewn most clearly in Figure 2, the pipes being
connected by right and left couplings to main pipes 12 placed lengthwise of the
chamber, one on each side (see also Figure 2), and placed directly above the rail
track 13 which is rivetted inside the chamber 1 and upon which the said loaded cars
rest whilst the wood is being operated upon.

page_text: The main pipes 12 are supplied from the boiler by suitable connections 14, and
each pipe is provided with a steam trap 15 (see Figure 2) at the lower end of the
chamber to permit of any water of condensation escaping from the pipes.
The chamber 1 is provided with a safety-valve 16 to relieve an over-accumulation
of pressure should the operator neglect his duty, and with a thermometer 17
by which the inside temperature is ascertained or determined with a view to
regulation.
The chamber is also fitted with a pipe 18 leading from a suitable air-pump or
compressor, and the amount of pressure attained within the chamber is indicated by
a gauge 23.
Three sets of cars 19, above referred to, are of advantage in using the apparatus,
one set for the inside carrying the wood being operated upon while another is being
loaded to be operated upon, and a third being unloaded, having been operated upon.
They are formed, as illustrated in Figure 2, with movable half-hoops 20 bolted to
cross-pieces 21, and are bent to clear the inner periphery of the radiator tubes 11.
The improved method of treatment by the use of the above described improved
apparatus is as follows :-
The loaded car of wood to be operated on is run into the chamber along the
rails 13, and the end doors 3 are then tightly closed; steam from the boiler is then
turned onto the radiator tubes 11 and the wood is heated to any desired degree and
for any desired length of time by the radiation of heat therefrom, the effect of which
is to open the pores of the wood and expel the aqueous vapours therefrom. If suffi-
ciently treated thus the steam may be then turned off, or it may be still admitted
to the radiator-tubes, and cold air is then forced by the pump or compressor into the
chamber until any desired high pressure is attained therein, when the action of the
pump may be for a while stopped. The heated air under this pressure quickly per-
imeates the wood and completes the vaporizing of its aqueous properties, the pressure
arising from which vapor or steam compensates for a consequent reduction of the
air pressure and the loss from the action of a condenser which automatically draws
away the vapors as hereinafter described, and which automatic action continues
until the vapor and water of condensation are all drawn away and the wood is
sufficiently dried, when a test or "pet" cock, hereinafter referred to, indicates dry
air in the chamber. The steam, if not previously turned off from the radiator tubes,
should now be turned off, and cold water should or may be turned on thereto to aid
in cooling the interior of the chamber and in condensing the aqueous vapor therein,
the air-pressure however being kept up by the pump, which is worked at intervals
during the entire process, if necessary for that purpose, and so as to close the pores
of the wood during the cooling thereof and force back thereinto all the resinous and
other preservative agents naturally contained in the wood, coagulating them and
pressing the wood into a more dense condition, the absence of watery particles pre-
viously driven off and condensed allowing of this and ensuring the preservation of
the wood from future decay from any natural causes. When the temperature has
been reduced say, to about 150° Fahrenheit, the air pressure is relieved, and is allowed
to escape by blowing off, and the chamber is opened and the loaded car of seasoned
wood is then withdrawn therefrom and the process or treatment thereof is com-
pleted.
By these means the wood is gradually, rapidly, and thoroughly dried, cooled, and
seasoned, so that neither cracking, nor checking, nor other alteration can occur
when exposed to the external air, as it is liable to do if not treated and cooled
under such pressure throughout; and moreover the wood seasoned by the above
described improved process has a very novel appearance, from its extreme
compactness of fibre and consequent improvement in colour.
In order to discharge the vapour and water of condensation expelled from the
wood by the above described treatment from within the chamber in or during the
treatment of the wood, and without lowering the pressure within the chamber as
the conditions consequent upon the principle of the said treatment necessitate for

page_text: the purpose specified, a condenser (above referred to) composed of a coil of pipe 24
in a vessel of cold water 25 is placed in connection with a stop-cock 26 used for
the above referred to drawing-off, and a similar connection may be made with a
cock at the other end of the chamber. The vapors expelled from the wood and
contained in the chamber collect mainly in the bottom thereof, and flow freely and
constantly to the condenser-coil into which they are automatically drawn chiefly by
a partial vacuum into a sealed receiver, one end of the coil being connected to the
stop-cock 26, while the lower end is attached to a sealing trap vessel 27, which is
provided with a combined float and valve 28, as shewn in the somewhat modified
arrangement illustrated in Figure 4. A vapor pipe 29 at its upper end is connected
to the chamber, and at its lower end is united with the coil 24 and is provided
with a stop-cock 30. The chamber is also provided with a testing or "pet"-cock
31 as above referred to. The outlet or waste pipe 32 of the sealing vessel 27 is
designed to dip into the fluid of the receiving vessel to excludo all air from it.
The condenser thus draws away the vapours by the pipes 26, 29, into the coil 24
in which there is a partial vacuum, the condensed fluid passing into the sealing
trap 27 until it lifts the float and valve 28 which liberates the fluid into the
receiving vessel, when the float and valve again drop to their normal position, and
without lowering the pressure in the chamber.
The amount of liquid to be taken away from the wood can be regulated by the
heat and pressure applied thereto within the chamber. The heat should properly
be between 200° and 300° Fahrenheit of dry heat, and the air pressure between
60 lbs. and 100 lbs. to the square inch.
The application of the condenser or of some equivalent means for drawing off the
vapours without lowering the pressure within the chamber is an essential element
in the principle of the above described improved process, as by its use alone the
process is made suitable and advantageous to and in the treatment of all kinds of
woods, the wood being perfectly dried and without a crack or check in any part.
If the chamber were opened and the vapours were allowed to escape suddenly, the
sudden removal of the pressure and the cold atmospheric-air striking the wood at
the same time would cause the wood to crack, and if the vapor were let off by any
of the known methods for blowing-off steam, the pressure which it is so desirable
to keep to avoid the cracking of the wood would be lost, and the process rendered
useless for its intended purpose, and this has been the principal fault of previous
methods of seasoning wood by the use of heat.
For convenience and economy it is of advantage to have two or more chambers 1
placed alongside, and connected by proper pipes and stop-cocks, and coils of iron
pipes may be secured around or horizontally along the inside of the chambers with
their ends projecting outside for external connections, or an annular steam-chamber
may be used. Stop-cocks, blow off and safety valves, pressure and water gauges,
and thermometers, should be attached to the chambers.
As shewn in the modified arrangement illustrated in Figure 4, a single coil of
piping is used around the chamber, the ends 33, 34, of the pipe projecting through
one end thereof; 35 shows the forcing air-pump with the pipe 18 fitted with a
stop-cock and check-valve leading to the chamber 1; 36 shews the steam cylinder.
Branch pipes with proper stop-cocks lead from 33, 34, to a cold water hydrant or
supply for the above referred to cooling purposes; 37 represents the supply, and 38
the waste-pipe for the condenser-tank 25.
It will of course be understood that the present Invention consists more
especially in the above described improved process for treating and seasoning all
kinds of wood and timber, than in any special apparatus to be employed in the said
treatment, as it is obvious that the above described treatment can be practically
effected in apparatus of different construction to what I have above described, and
the inventors therefore wish it to be clearly understood that although they have
described certain apparatus as being the best of which they are at present aware for
carrying the principle of their Invention into effect, they do not limit themselves to

page_text: its use and reserve to themselves the right to use other contrivances for the
particular means herein before described, such as substituted means for the trap-
vessel; other means for heating the chamber, such as heated air or superheated
water, the superheating of the steam admitted to the coil or radiators by an
intermediate furnace, but the supply of dry air under high pressure and the free
liberation and sealed condensation of the fluids vaporized by the beated air under
pressure, are essential features of the process intended to be protected by the said
Letters Patent.
It will be seen also that the contents of the chamber are heated, and the pressure
is obtained by distinct means and operations, and that the heat and pressure are
confined without escape from first to last; when the pressure is once obtained very
little work from the pump is afterwards needed, and thus the fibres of the wood
are compressed and dried at the same time.
Having now described the nature and objects of the said Invention together
with the manner in which the same is to be or may be performed or carried into
practical effect, I would remark in conclusion that what I claim as the Invention
communicated to me by the above named Thomas Alexander Dowling and John
Hardman, is,
First. The treating, drying, or seasoning of all kinds of wood or timber by
heating the same in a steam tight chamber, and by subjecting it to high air-
pressure while being subjected to the treatment by heat, whereby the aqueous and
other fluids or vapors are evolved, and are automatically drawn off by condensing
apparatus, and by cooling it while still under high air-pressure so as to render it
not liable to crack or check upon exposure to the external air, substantially as
herein before described.
Second. The adaptation and employment of a sealed operating chamber provided
with an internal coil of pipe or other contrivance for heating in combination with
an air-pump for high pressure, a condensing apparatus for vaporized fluids, and a
sealed vessel for the condensed liquid, all arranged substantially in the manner and
for the purposes herein before described.
And, Third. The provision and use of an automatic condensing and sealing
apparatus in combination with an air forcing pump and a heating apparatus, when
used with a sealed operating chamber for treating and seasoning wood and timber
of all kinds, substantially in the manner described.
In witness whereof, I, the said Hugh Hardman, have hereunto set my hand
and seal, this Seventeenth day of June, in tho year of our Lord One
thousand eight hundred and seventy-nine.
ITTATT
HUGH HARDMAN, (14.8.)