Improvements in and relating to the Preservation and Fire-proofing of Wood and the like.
Year: 1899

page_text: [Communicated from abroad by FRANZ KONRAD, of Münster, Westphalia, in the
Empire of Germany, Engineer.]
Improvements in and relating to the Preservation and Fire-proofing
of Wood and the like.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
The present invention relates to an improved method of and apparatus for
preserving as well as rendering incombustible wood, timber, and the like.
It is well known that preservation of wood may be effected by treating or
impregnating it with suitable solutions containing salts adapted to combine with
the albuminous matters of the wood in order to form innoxious and insoluble com-
pounds with the latter. It is also known that wood and the like may be rendered
fireproof by impregnating it with suitable substances such as alum, borax, vitrol of
iron, water-glass.
In accordance with the present invention wood, timber, and the like are not
only rendered durable but also incombustible and with this end in view the novel
feature of the present invention consists in preserving on the one hand and fire-
proofing on the other hand the said wood or the like by the employment of separate
means or solutions, which do not act independently of each other, one solution for
the preserving and the other for the fire-proofing only, but which being applied one
after the other act in combination and perform by such combined mutual action
both the said purposes aimed at. The combined effect is therefore greater than
the sum of the single actions of the said solutions.
The invention essentially consists in impregnating the wood or the like to be
treated first with a solution adapted to render the albuminous matters innoxious,
and then with a solution capable of combining with the former, in order to form
incombustible salts.
In carrying my invention into effect I prefer as being most suitable, to
impregnate the wood or the like first with linie-milk and then with a solution of
ammonia and boric acid. The treatment of the wood or the like with the said
solutions may be effected by means of any suitable apparatus.
The accompanying drawing illustrates in sectional elevation an arrangement
adapted to carry out my said invention.
The air-dried or seasoned timber, wood and the like to be treated is placed
in a suitable chamber a so that it rests with the root-end upon a grating a¹. The
chamber a is then hermetically closed and the air exhausted therefrom and the
wood by means of an air pump connected with the pipe b. By this operation the
air is not only withdrawn but a partial vacuum also formed in the said chamber.
After this the first impregnating liquid preferably a lukewarm weak lime-milk
is allowed to flow through the pipe c into the chamber a and a force-pump applied

page_text: by which the said lime-milk is forced into the pores of the wood. The completion
of this operation will be indicated as soon as lime-milk drops out through the
controlling outlet d (at the upper part of the chamber) which lime milk may be
collected in a suitable vessel g by means of a bell-mouthed tube h. The wood thus
thoroughly saturated is then slowly dried by blowing dry air through the said
chamber.
'
After drying, the wood is similarly treated with the second impregnating solution
which must be of such a nature that by its combination with the impregnating
matters of the first solution insoluble compounds are formed which remain within
the substances of the wood rendering it durable and fire-proof. A solution of
sulphate of ammonia and boric acid is most suitable for this purpose as by this
solution in combining with the first solution incombustible salts are formed.
The second impregnating solution may be applied in a heated state. For heating
the solution a separate boiling vessel e may be provided into which, a continuous
working, fresh solution may be supplied in any suitable manner from separate
supply tanks f.
In practice I employ a milk of lime containing about seven gr. pulverized
unslaked lime to every one thousand gr. of water; and a solution containing
about 14 gr. of boric acid and 115 gr. of sulphate of ammonia to every 1000 gr. of
water. The time of exposure to the action of the solution last referred to will of
course depend upon the dimensions of the lumber or timber to be treated generally
from about four to five hours. As is well known, the decomposition of the
albumen in wood under atmospheric influences is the primary agent of decay,
the lime acts as an antiseptic or preservative upon the albumen, and tends to
coagulate the same and prevents its decomposition, while the incombustible and
fire-proof salts (borate of lime and gypsum) formed render the wood fireproof, as
above stated.
Having now particularly described and ascertained the nature of this
invention, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is:-
-
1. The process which consists in first saturating the wood with milk of lime,
second drying the said wood, and then saturating-the-same_with_a solution of
boric acid and ammonia, substantially as and for the purpose set forth.
2. The process which consists in first saturating the wood with a warm milk of
lime, second drying the thus prepared wood, and third saturating the same with a
hot solution of boric acid-and ammonia, for the purpose set forth.
Dated this 24th day of February 1899
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.