Process for the Preservation of Wood.
Year: 1899

page_text: Date of Application, 17th Aug., 1899
Complete Specification Left, 9th Apr., 1900-Accepted, 12th May, 1900
PROVISIONAL SPECIFICATION.
Process for the Preservation of Wood.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by the Firm of Berliner Holzcomptoir, of 29, Hardenburg Strasse, Char-
lottenburg, near Berlin, Germany,) to be as follows:-
One of the best known means for the preservation of wood against decay is tar-
oil. This substance is consequently employed in large quantities for this purpose,
in particular for the preservation of railway sleepers and the like.
For effectually carrying out the process of preservation, it is necessary to
saturate the wood to be protected thoroughly in all its parts, and this is effected
in practice by causing the wood to absorb a definite quantity of the tar-oil. Thus,
according to the regulations of the Prussian State Railway, sleepers of pine or
beech of 27 meters length and 0'16 by 026 meters thickness, should at least
absorb 36 kilogramms of tar oil. This comparatively large quantity is necessary
in order to ensure that the sleeper shall contain tar oil as much as possible in
every part.
In view, however, of the strong antiseptic properties of tar oil, a much smaller
quantity thereof would be sufficient to protect the sleeper sufficiently against
decay. It has, however, not been possible heretofore to effect the perfect satura-
tion of such a sleeper in all its parts by means of a smaller quantity of tar oil,
and on this account the above mentioned large excess of tar-oil is employed. By
this means very considerable and unnecessary expenses are incurred, which are
of importance on account of the very large quantity of wood that has to be
preserved.
My correspondents have invented a process which enables wood to be saturated
with much smaller quantities of tar-oil while effectually carrying out the object
of protecting the wood against decay in a most perfect manner and at a very
small cost.
For this purpose the known fact is utilised that tar-oil is readily and largely
dissolved in strong aqueous soap solution. If now such a soap-tar-oil solution
be poured into a large quantity of water, there is produced an exceedingly fine
emulsion (not solution) of tar-oil with water, or dilute soap solution, from which
the tar-oil separates, as a liquid, only very slowly.
By this means it is rendered possible to introduce the tar oil in an exceedingly
fine state of subdivision in larger or smaller quantities into the innermost parts
of the wood, and thus to effectually protect such parts against decay. The soap
solution which is at the same time introduced into the wood has no appreciable
effect on this protection; the water very soon evaporates in the open air and the
tar-oil remains in the wood.
The advantages of this process over that at present employed are as follows: -
1. The consumption of much smaller quantities of tar oil for effecting the
perfect saturation of wood and the resulting great economy in the cost of materials,

page_text: 2. The method of working is much cleaner and the workmen are conse-
quently better protected..
While on the one hand according to the present process, the wood, when
taken out of the saturating vessels, is covered with oil and consequently, in hand-
ling the same, the body and clothes of the workmen are smeared with the tar-
oil, and also, in particular in hot weather, the workmen also suffer in health
therefrom, on the other hand, the wood treated according to the present improved
process, comes clean out of the saturating vessel, and the above mentioned detri-
mental effect on the health of the workmen is obviated.
3. The possibility of saturating large quantities of wood with tar-oil.
In the Prussian State Railways from 4 to 5 million sleepers are annually
treated. If all these sleepers had to be saturated with tar-oil according to the
existing regulations, there would be required for this purpose about 150 million
kilogrammes of tar-oil, a quantity which cannot be obtained in trade at approxi-
mately low prices, while on the other hand, the quantities of tar-oil which are
requisite for the above improved process can be obtained very readily.
All kinds of soap solution can be employed more or less usefully; for example,
the following process may be recommended:
100 parts by weight of resin are saponified with the necessary quantity of soda
and an aqueous soap solution of about from 750 to 1000 parts by weight is pre-
pared. In this soap solution there are introduced under slight heating from 750
to 1000 parts of tar-oil, thereby producing a thick, not quite clear, solution. If
now this solution be poured slowly under continual stirring into 10000 parts by
weight of water, there is produced a milky emulsion of tar-oil with water suitable
for the saturation of wood in which the tar-oil is so finely divided, that on filter-
ing it through filtering paper, it cannot be separated from the water. This liquid
is forced by pressure into the wood in suitable apparatus of known construction.
With the proportions given the emulsion contains in 11000 litres 1000 kilogram-
mes of tar-oil. If of this emulsion 35 kilos. he forced into a sleeper of the above
stated dimensions and weighing from 60 to 100 kilos., then there will be intro-
duced about 3'2 kilos. of tar-oil, a quantity which, owing to its very strong anti-
septic action, will be fully sufficient to protect the wood against decay, as it will
be dispersed in a finely divided condition in all parts of the saturated wood.
It is to be understood, however, that the quantity of tar-oil can be varied at
will according to circumstances.
The tar-oil employed can either be free from carbolic acid, or it may contain
the same. The antiseptic properties of the tar-oil free from carbolic acid can, if
desired, be supplemented by the addition of naphthaline and pyridine. Also,
the durability of the emulsion with certain kinds of tar-oil can be increased by
an addition of ammonia.
Dated this 17th day of August 1899
ABEL & IMRAY
Agents for the Applicant.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by the Firm of Berliner Holzcomptoir, of 29, Hardenburg Strasse, Char-

page_text: lottenburg, near Berlin, Germany) and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following,
statement:
-
One of the best known means for the preservation of wood against decay is tar-
oil. This substance is consequently employed in large quantities for this purpose,
in particular for the preservation of railway sleepers and the like.
For effectually carrying out the process of preservation, it is necessary to
saturate the wood to be protected thoroughly in all its parts, and this is effected
in practice by causing the wood to absorb a definite quantity of the tar-oil. Thus,
according to the regulations of the Prussian State Railway, sleepers of pine or
beech of 27 meters length and 0'16 by 0'36 meters thickness, should at least.
absorb 36 kilogramms of tar oil. This comparatively large quantity is necessary
in order to ensure that the sleeper shall contain tar-oil as much as possible in
every part.
In view, however, of the strong antiseptic properties of tar-oil, a much smaller
quantity thereof would be sufficient to protect the sleeper sufficiently against
decay. It has, however, not been possible heretofore to effect the perfect satura-
tion of such a sleeper in all its parts by means of a smaller quantity of tar-oil,
and on this account the above mentioned large excess of tar oil is employed. By
this means very considerable and unnecessary expenses are incurred, which are
of importance on account of the very large quantity of wood that has to be
preserved.
My correspondents have invented a process which enables wood to be saturated
with much smaller quantities of tar oil while effectually carrying out the object
of protecting the wood against decay in a most perfect manner and at a very
small cost.
For this purpose the known fact is utilised that tar oil is readily and largely
dissolved in strong aqueous soap solution. If now such a soap-tar-oil solution
be poured into a large quantity of water, there is produced an exceedingly fine
emulsion (not solution) of tar-oil with water, or dilute soap solution, from which
the tar-oil separates, as a liquid, only very slowly.
By this means it is rendered possible to introduce the tar oil in an exceedingly
fine state of subdivision in larger or smallér quantities into the innermost parts
of the wood, and thus to effectually protect such parts against decay. The soap
solution which is at the same time introduced into the wood has no appreciable
effect on this protection; the water very soon evaporates in the open air and the
tar-oil remains in the wood.
The advantages of this process over that at present employed are as follows:-
1. The consumption of much smaller quantities of tar-oil for effecting the
perfect saturation of wood and the resulting great economy in the cost of materials.
2. The method of working is much cleaner and the workmen are conse-
quently better protected.
While on the one hand according to the present process, the wood, when
taken out of the saturating vessels, is covered with oil and consequently, in hand-
ling the same, the body and clothes of the workmen are smeared with the tar-
oil, and also, in particular in hot weather, the workmen also suffer in health
therefrom, on the other hand, the wood treated according to the present improved
process, comes clean out of the saturating vessel, and the above mentioned detri-
mental effect on the health of the workmen is obviated.
3. The possibility of saturating large quantities of wood with tar-oil.
In the Prussian State Railways from 4 to 5 million sleepers are annually
treated. If all these sleepers had to be saturated with tar-oil according to the
existing regulations, there would be required for this purpose about 150 million
kilogrammes of tar-oil, a quantity which cannot be obtained in trade at approxi-
mately low prices, while on the other hand, the quantities of tar oil which are
requisite for the above improved process can be obtained very readily.

page_text: All kinds of soap solution can be employed more or less usefully; for example,
the following process may be recommended:
100 parts by weight of resin are saponified with the necessary quantity of soda
and an aqueous soap solution of about from 750 to 1000 parts by weight is pre-
pared. In this soap solution there are introduced under slight heating from 750
to 1000 parts of tar-oil, thereby producing a thick, not quite clear, solution. If
now this solution be poured slowly under continual stirring into 10000 parts by
weight of water, there is produced a milky emulsion of tar-oil with water suitable
for the saturation of wood in which the tar oil is so finely divided, that on filter-
ing it through filtering paper, it cannot be separated from the water. This liquid
is forced by pressure into the wood in suitable apparatus of known construction.
With the proportions given the emulsion contains in 11000 litres 1000 kilogrammes
of tar oil. If of this emulsion 35 kilos. be forced into a sleeper of the above
stated dimensions and weighing from 60 to 100 kilos. then there will be intro-
duced about 3'2 kilos. of tar oil, a quantity which, owing to its very strong anti-
septic action, will be fully sufficient to protect the wood against decay, as it will
be dispersed in a finely divided condition in all parts of the saturated wood.
It is to be understood, however, that the quantity of tar-oil can be varied at
will according to circumstances.
The tar-oil employed can either be free from carbolic acid, or it may contain
the same. The antiseptic properties of the tar oil free from carbolic acid can, if
desired, be supplemented by the addition of naphthaline or pyridine.
Also,
the durability of the emulsion with certain kinds of tar-oil can be increased by
an addition of ammonia.
If it be desired to impregnate the wood with smaller quantities of tar-oil, tar-
oil free from carbolic acid is employed, while when impregnating with larger
quantities of tar-oil (such as, for example from 10 kilos. upwards per one tenth of
a cubic meter) any tar-oil, no matter whence it may be derived and whether con-
taining carbolic acid or not, may be used.
When only small quantities of tar-oil are to be introduced comparatively dilute
emulsions are of course used, while in other cases more or less concentrated emul-
sions are employed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
-
Process for impregnating wood with any desired quantity of tar-oil, which
consists in treating the wood with a tar-oil emulsion produced by stirring together
a tar-oil-soap solution with water, substantially as described.
ABEL & IMRAY
Agents for the Applicant.