TREATING WOOD AND VEGETABLE FIBRE IN GENERAL BY ⚫ CARBURETTED STEAM' AND COMPRESSION TO STRENGTHEN AND PRESERVE SUCH MATTERS FROM DECAY
Year: 1873

page_text: LETTERS PATENT to Edward Thomas Hughes, of the Firm of Hughes
and Son, Patent Agents, 123, Chancery Lane, London, for the In-
vention of "TREATING WOOD AND VEGETABLE FIBRE IN GENERAL BY
⚫ CARBURETTED STEAM' AND COMPRESSION TO STRENGTHEN AND PRESERVE SUCH
MATTERS FROM DECAY."-A communication from abroad by John
D
PROVISIONAL SPECIFICATION left by the said Edward Thomas
Hughes at the Office of the Commissioners of Patents, with his
Petition, on the 22nd October 1873.
I, EDWARD THOMAS HUGHES, of the Firm of Hughes and Son,
3 Patent Agents, 123, Chancery Lane, London, do hereby declare the
nature of the said Invention for "TREATING WOOD AND VEGETABLE FIBRE
IN GENERAL BY CARBURETTED STEAM' AND COMPRESSION TO STRENGTHEN AND
PRESERVE SUCH MATTERS FROM DECAY," a communication to me from
i

page_text: abroad by John Bennington Blythe, of Bordeaux, France, to be as
follows:-
My Invention for improvements in means and apparatus employed
for seasoning, toughening, compressing, and preserving wood, and
obtaining therefrom acetic acid and other products, part of which
improvements are applicable to the treatment of vegetable fibre in
general, are as follows:- I construct a strong iron chamber capable
of supporting an internal pressure of (8) eight atmospheres, preferably
of a cylindrical form, like the ordinary creosoting cylinder. I surround
it with flues so as to heat it externally over the whole of its surface,
this I call in my description the oven; a long iron boiler extending
the whole length of the oven is set in the same brickwork below it, and
both the oven and the oven above it are heated by same furnace or
furnaces.
Pipes with stop-cocks connect the top of the boiler with the upper
part of the oven, and a return pipe, also provided with a stop-cock,
connects the bottom part of the oven with the bottom part of the boiler.
Condensing apparatus is attached to the oven, so as to permit the
discharge of the steam formed in it through safety valves in case of the
interior pressure becoming too great, and also to enable me to distil
off the steam and gases into collecting tanks when the wood has become
sufficiently treated.
I place the wood in the oven and charge the boiler with water
15 to 20% of the weight of the wood under treatment, according to
its state of dryness, I find to be sufficient. And to the water. I add
one-third to one-fifth of its weight of heavy hydrocarbon oil, such the
heavy coal-tar oil known as creosote, or other hydrocarbon matter
heavier than water.
The quantity of hydrocarbon oil or matter that I put into the boiler
is very important, and greatly effects the chemical decomposition that
takes place in the oven; too little hydrocarbon will not or will only
imperfectly decompose the incrustations of the cellulose, while if too
much is used it will only be deposited as oil upon the wood. The
economy of the hydrocarbon oil used is very great, and besides I have
the certainty that by using a small quantity of hydrocarbon oil with
a large quantity of water that I avoid all danger of explosion when the
oven is open to remove the wood, or from escaping gases during the
*operation.

page_text: I heat the water and oil together and make "carburetted steam,'
which passes into the oven by the upper pipes, while the liquids
condensed in the oven return to the boiler by the lower pipes which.
connect them together.
After the temperature in the oven has attained 212 degrees
Fahrnhoit the heating is continued till all the albumen and sap in the
wood is decomposed into resin, acetic acid, and oleaginous matter..
The time required for this decomposition depends upon the thickness.
of the wood, therefore wood of equal thickness or thereabouts should.
always be treated together (2) two hours per inch of thickness in an oven
at a temperature of 290 or 300 degrees will treat any wood however
recently felled and cut; but some woods require less heat than others;
wood that is to be simply preserved against dry rot and strengthened
does not require so long a treatment as wood that is to be rendered
non-absorbent of water. When the wood has been thus heated a
sufficient time the condensible products are distilled over into tanks
for after treatment, and when all has come off and no pressure remains
in the oven it is opened and the wood drawn out, which can now be
pressed, bent, or moulded into any shape.
If the wood is for railway sleepers I press the bearings of the rail
or chair down to a guage, leaving the other parts of the sleeper as they
came out of the oven; I press a paving block by pressing it into a
tapered mould, so as to densify and reduce the summit of the block,.
only, and for other purposes I bend or press the whole of the piece as :
I may require. Deck planks, flooring, and thin boarding, having"
been first treated as before described; I pass through rollers to effect:
the surfacing that is now done by planing; and by this means planks
and boards sawn from recently felled trees can be rendered fit for use.
in an incredibly short time.
Two days is sufficient to change a growing tree at any season of the
year into prepared flooring boards, seasoned and colored by my oven
treatment, and afterwards densified and rolled to surface by passing
through compressing rollers.
All woods will support compression of the whole or any part of the
same piece, and will retain the form given them under water. Air,
hardens fresh treated wood quickly, but generally speaking may be,
pressed within 24 hours after the oven treatment.
:
.

page_text: で
As my process closes the fibrous contexture of the allulose, giving
density and toughness, as well as inevitably preserving from decay and
dry rot any wood that has been treated by it, it will not always bo
necessary to employ mechanical pressure, as for many uses the wood
will be found to have been sufficiently hardened.
All kinds of vegetable fibre may be treated by "carburated steam,"
but as the minute division of the fibres facilitates greatly its action.
upon the incrusting matter a much shorter time and a lower temperature
must be employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Thomas Hughes in the Great Seal Patent
Office on the 22nd April 1874.
TO ALL TO WHOM-THESE PRESENTS SHALL COME, I, EDWARD
THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents, .
123, Chancery Lane, London, send greeting.
-
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of October, in the year,
of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Edward Thomas Hughes, 2
Her special licence that I, the said Edward Thomas Hughes, my
executors, administrators, and assigns, or such others as I, the said
Edward Thomas Hughes, my executors, administrators, and assigns,.
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "TREATING WOOD AND VEGETABLE FIBRE
IN GENERAL BY CARBURETTED STEAM AND COMPRESSION TO STRENGTHEN AND
PRESERVE SUCH MATTERS FROM DECAY," a communication to me from abroad a
by John Bennington Blythe, of Bordeaux, France, upon the condition
(amongst others) that I, the said Edward Thomas Hughes, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and.

page_text: ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edward Thomas Hughes, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Sheet of illustrative Drawings, and to the figures and letters marked
thereon, that is to say :—
This Invention for improvements in means and apparatus employed
for seasoning, toughening, coloring, compressing, and preserving wood,
and obtaining therefrom acetic acid and other products, part of which
improvements are applicable to the treatment of vegetable fibre in
general are as follows:-I construct a strong iron chamber capable of
supporting an internal pressure of eight atmospheres, preferably of a
cylindrical form like the ordinary creosoting cylinder; I surround it
with flues so as to heat it externally over the whole of its surface; this
I call in my description the oven. A long iron boiler extending the
whole length of the oven is set in the same brickwork below it, and both
the boiler and the oven above it are heated by the same furnace or
furnaces.
•
Pipes with or without stop-cocks connect the top of the boiler with
the upper part of the oven, and a return pipe connects the bottom
part of the oven with the bottom part of the boiler. Condensing
apparatus is attached to the oven so as to permit the discharge
of the steam and gases through safety valves, in case of the interior
pressure becoming too great, and also to enable me to distil off these
matters into collecting tanks when the wood has been sufficiently
) treated.
In the accompanying Drawings, Fig. 1 is a longitudinal section
at C, D; Fig. 2, a longitudinal section at A, B; Fig. 3, a transverse
section at E, F; and Fig. 4, a transverse section at G, H.
a, is the oven with its door b; c, bricked chambers or flues surround.
5-ing the oven a; d, boiler to heat water and hydrocarbon oil by the fire
on the grate e; f.f.f, pipes to admit steam from the boiler d'into the

page_text: t
oven a; h, return pipe between the bottom part of the oven a and the
bottom part of the boiler d, to allow the condensing liquids to return
from the oven a to be re-evaporated in the boiler d and so to establish a
circulation similar to that in hot water heating apparatus; j, discharge
flue into the chimney k; l, m, n, dampers to direct the furnace gases
round the oven a, or round the closed tank y as the heat may be
required; p, condenser to condense steam from the oven a, escaping by
the safety and discharge valve x into the tank q; r, closed vessel for
charging the boiler d'; the liquid matters are filled into this vessel by
the stop-cock 8, and this being closed, the stop-cock u connecting the
top of the vessel with the oven a, and the stop-cock t connecting the
bottom of the vessel with the boiler d are opened, and the boiler is
charged by the pressure of steam upon the liquid.
OC
I place the wood in the oven and charge the boiler with water (15 to
25 per cent. of the weight of the wood under treatment, according to
its state of dryness, I find to be sufficient), and to the water I add one-
fifth part (or less when the matter employed is rich in carbolic acid) of
its weight of heavy hydrocarbon oil, such as the heavy coal tar oil
known as 66
"
cressote or other hydrocarbon matter heavier than water.
The hydrocarbon oil used should contain at least 5 per cent. of
creosote or carbolic acid.
The quantity of hydrocarbon oil put into the boiler must be pro-
portioned to the carbolic acid it contains, most of the hydrocarbon oils
of commerce are refuse products and contain very variable quantities
of this acid, though most of them are known as "creosote oils,
therefore hydrocarbon oils poor in carbolic must have richer oils
mixed with them so as to proportion the quantity of carbolic acid in
the hydrocarbon oil with the quantity of wood to be treated. The
quantity is best found by a trial operation.
Different kinds of wood require different quantities of hydrocarbon oil
to treat them effectually for the various purposes for which wood is
used, and it is always much better to have in the boiler no more
hydrocarbon oil than the wood to be treated will take up in each
operation.

page_text: condensed in the oven return to the boiler by the lower pipes which
connect them together.
After the temperature in the oven has attained 212 degrees Fahrenheit
the heating is continued until all the albumen and sap in the wood
is decomposed into gummy and resinous matter that remains in the
pores, and which on hardening acts as a cement in holding them
together.
The time required for this decomposition depends upon the thickness
of the wood, therefor wood of equal thickness or thereabouts should
always be treated together; two hours per inch of thickness, in an oven
at a temperature of 290 to 300 degrees will treat any wood however
recently felled and cut; but some woods require less heat than others;
wood that is to be simply preserved against dry rot and strengthened
does not require so long a treatment as wood that is to be rendered non-
absorbent of water.
When the wood has been sufficiently treated the steam and gases in
the oven are distilled over into tanks. The tarry matter and water
remaining in the boiler is run out and fresh quantities of hydrocarbon
oil and water are charged into the boiler for the next operation; this
will not be necessary when the same kind and quantity of wood is being
treated; practice will soon show the proportion of each matter that has
been taken up during the operation, and these quantities only will have
to be run into the boiler. Some woods will produce more acids than
others, and in treating such woods a part of the water in the boiler will
have to be run off and renewed at the end of each operation. The
residual matters may all be treated to obtain acetic acid and other
products as they are now obtained from wood by destructive distillation.
Wood after this treatment can be pressed, rolled, or moulded into
shape; if for railway sleepers I press the bearings of the chair or rail
down to a guage, or I pass the sleepers through rollers, that carry moulds
for the seatings. I wish to form or projecting parts that groove the
sleepers in their entire length so as to imbed the flanges of rails in a
longitudinally supported road.
For tramways I use rolled longitudinal sleepers, grooved to imbed a
light iron rail when necessary, but always compressed sufficiently to bear
the wear and tear of the wheels. These longitudinal sleepers are carried
by a transverse planking treated by my process and compressed by

page_text: •
planks are dovetailed into the longitudinal sleepers to keep them in
guage. Paving blocks pressed in tapered moulds so as to densify and
reduce in size the top parts of the blocks and allow foothold for horses
are fitted in level between the two longitudinal sleepers, the whole
forming a cheap useful road entirely of compressed prepared wood very
durable and quite sufficient for light traffic.
Deck planking, flooring, thin boarding, and veneers having been first
treated as before mentioned I pass through rollers to effect the surfacing
that is now done by planing, and by this means planks, boards, and
veneers sawn from recently felled trees can be rendered fit for use in a
very short time.
Air quickly hardens the surface of freshly treated wood, but it can
always be compressed within twenty-four hours after the treatment in
the oven.
If the treatment has been sufficient to decompose the sap the
wood will retain the form given it under water, but as my process always
closes the fibrous contexture of the cellulose, giving density and
toughness as well as inevitably preserving from decay and dry rot any
wood that has been treated, it will not always be necessary to employ
mechanical pressure, as for many uses the wood will be found to have
been sufficiently hardened without.
I imitate the color and odour of foreign hard woods by passing wood
in coming out of the oven through tanks containing scented coloring
liquids. The liquid is immediately absorbed by the wood, which is then
passed as before described through compressing rollers or pressed into
moulds.
All kinds of vegetable fibre may be treated by "carburetted steam,"
but as the minute divisions of the fibres facilitates greatly its action
upon the incrusting matter a much shorter time and a lower temperature
must be employed.
I am aware that hydrocarbon vapour has been employed to inject
wood with hydrocarbon oils, and that it has been also proposed to
strengthen wood by compressing its fibres together; and I do not claim
the use of hydrocarbon vapour used by itself to inject or preserve wood
and vegetable fibre from decay, neither do I claim the use of steam from
water generated in a boiler by itself and, employed to carry or distribute
hydrocarbon vapour, from an evaporating boiler or retort into a cylinder