Improvements in and relating to the Vulcanisation of Timber.
Year: 1894

page_text: Date of Application, 27th Oct., 1894-Accepted, 1st Dec., 1894
COMPLETE SPECIFICATION.
[Communicated from abroad by FRIEDRICH MAURICE GRUMBACHER, of
Linkstrasse 26, Berlin, in the Kingdom of Prussia and German Empire,
Merchant.]
Improvements in and relating to the Vulcanisation of Timber.
I, WILLIAM EDWIN HEYS of 70 Market Street, Manchester, in the County
of Lancaster, Patent Agent, 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:-
In the processes hitherto employed for vulcanising timber, a common fault has
been that the interior of the wood has remained in a damp condition. During the
drying process the water contained in the wood is converted into steam and the outer
portion of the timber is dried and compressed by the heat and the pressure to
such an extent as to prevent the escape of water from the centre.
Should a
temperature sufficiently high to effect the internal drying be employed, then a
timber results which in the course of a few months warps and splits. This fault
was apparent in timber treated by the known process in which the drying was
effected by pressure and a heat sufficient to dissipate the moisture in the interior.
of the wood. In another process the timber is treated with dry air at such a
pressure that the sap is neither boiled nor vaporised, whilst according to a modifi-
cation of this process the wood is first heated and is then cooled by compressed air.
The resisting properties imparted to the cellulose by vulcanisation is caused by
the combination of the oxyquinoline antiseptic substances contained within the
internal cellular substance. To effect this combination it is necessary to employ a
high temperature. But as damp cellulose is decomposed by great heat, it becomes
necessary to employ a perfectly dry process.
According to this invention the drying of the fresh wood is effected in a vessel in
which it is completely freed from all moisture by being subjected to a temperature
not exceeding 120 degrees. The vulcanising is then completed by the employment
of a greater pressure and a higher temperature.
The accompanying drawings to which reference is hereinafter made, illustrate the
apparatus employed in carrying this invention into effect.
Figure 1 represents a longitudinal section of the vessel within which the drying
is effected.
Figure 2 illustrates a cross section of the same vessel.
The vessel A within which the timber is placed is furnished with a steam coil b
the spirals of which are capable of movement backwards and forwards within the
vessel. The steam enters at m and passes through the coil into the condenser a or
is allowed to escape. The upper part of the vessel A carries a dome D provided
with a waste pipe c fitted with a valve d which permits the escape of the steam
formed from the moisture in the timber under treatment. In order to enable the
process to be watched, one end of the vessel A carries a vertical tube e the ends of
which communicate with the interior of the vessel. This tube is surrounded by a
second tube f and the space between them is supplied with cold water by a pipe g.
An outlet pipe / conducts the water away. The tube e is formed or has combined
with it a continuation i consisting of a glass tube preferably graduated and in which
accumulates any condensations from the tube e. A cock K allows this water to be
run off into a suitable drain or receptacle. The drying process may be considered
complete when no more condensation takes place within the tubes e or i.
The valve d of the steam outlet G is now closed; the valve O on the air supply
pipe is opened and air is pumped into the vessel A by the pump P at a pressure

page_text: of about 10 atmospheres and the temperature of the steam coil is raised to about
250 degrees C.
The vessel A is provided with rails's supon which runs a wagon or wagons W
carrying the timber to be treated. For the entrance and exit of the wagon one
end B of the vessel A is removable. This end makes an air tight joint with the
vessel and is held in place by means of a number of screws or clamps n or by other
suitable devices.
A pressure gauge p and a pyrometer q are combined with the vessel to indicate
the pressure and the temperature.
A safety valve is also preferably employed to prevent any undue rise in
pressure and any moisture from the wood is conducted into a reservoir under. the
vessel whence it may escape through the cock t.
In the hitherto employed methods of vulcanising the wet cellulose began to
decompose at a much lower temperature than 200 degrees C., but experiments
proved that cellulose will easily withstand over 200 degrees C., if its moisture has
first been removed.
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 :-
The hereinbefore described process for vulcanising wood, consisting in first
subjecting the wood to a preliminary drying at a comparatively low temperature
and then to complete vulcanisation under pressure and at a higher temperature
substantially as and by the means hereinbefore described.
Dated this 26th day of October A.D. 1894.