IMPROVEMENTS IN PRESERVING WOOD
Year: 1866

page_text: PROVISIONAL SPECIFICATION -left by John Nicholls Browne at the
Office of the Commissioners of. Patents, with his Petition, on the 7th.
August 1866. A communication from abroad by Louis Robbins, residing
at the City of New York, United States of America.
I, JOHN NICHOLLS BROWNE, of 31, Elgin Crescent, Notting Hill, in the
County of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRESERVING WOOD," to be as follows:->
It is a well known fact that wood when cut down and separated from the
roots which supply it with its antiseptics immediately becomes affected by.
exposure to the heat and the moisture of the atmosphere, the former of which
rapidly dissipates the 'fluid or sap of the wood, while the latter impregnates
the woody fibres with substances which the wood while growing by its
antiseptics entirely excluded. These alternate actions upon the wood gradually
and finally cause it to decay; to prevent this decay of wood is therefore the
object of the present Invention.
The method consists in subjecting the wood to a preservative process, by
which nearly all of its antiseptics are retained within the same, and for those
lost supplying such substances as will prevent their further waste, at the same
time closing the pores and forming such a combination with the fibres of the
wood as will effectually prevent the deteriorating effects of either heat or
moisture at ordinary temperatures, or of both, upon the same, as herein-before
alluded to.

page_text: The wood to be preserved is placed in a close chamber and subjected to the
action of the vapour of coal tar, resin, or oleaginous substances or compounds.
For this purpose a retort is employed, into which the coal tar or other sub-
stance is placed, and is vaporized by heat applied externally; the vapors thus
generated are conducted into the chamber containing the wood. The heat
thus applied first causes the surface moisture of the wood to be removed
therefrom, taking the form of steam, and condensing on the sides of said
chamber, from which it is drawn off through pipes, which may be placed in
or near the bottom. Having thus removed the surface moisture from the
wood it is then thoroughly impregnated and saturated through all its pores
and fibres by the oleaginous vapors and heavier products of the distillation
until it is made impervious to moisture, and so as to entirely resist the action
of the atmosphere, when it may be removed from the chambers through the
doors; the chambers are then again to be charged with wood, and so on as
long as may be desired.
In the operation of the process a temperature of from 212 degrees to 250
degrees Fahrenheit is sufficient to remove the surface moisture from the
wood, but to saturate the same with oleaginous vapors and other products it
is best that the temperature should be raised to 300 degrees Fahrenheit, or
higher if necessary. Any number of chambers may be employed, each
chamber being connected by a pipe with the retort, and each chamber is
provided with a door through which a wagon on which the wood to be pre-
served is loaded may be run into the chamber.
From the above description it is apparent that the wood is more completely
saturated with the préservative compound than has been or can be done by
any of the processes heretofore in use, for the reason that the preservative
compound is caused to permeate the pores and fibres of the wood in a
vaporized state, while in the others it is made to enter in a liquid state, and
it is also evident that it is accomplished in an economical, expeditious,
effective, and practical manner.