Improvements in Compressing Wood, and Utilizing Certain Waste Products therefrom.
Year: 1896

page_text: Date of Application, 17th Mar., 1896
Complete Specification Left, 15th Dec., 1896-Accepted, 6th Mar., 1897
PROVISIONAL SPECIFICATION.
Improvements in Compressing Wood, and Utilizing Certain Waste
Products therefrom.
We, ALEXANDRE DE PONT of Hest Bank Lancaster in the County of
Lancaster Manufacturer and SILVIUS DE PONT of Bare Lancaster aforesaid,
Manufacturer, hereby declare the nature of this invention to be as follows:-
This invention relates to a process for compressing natural wood to any required
density which will render or leave the wood so treated incapable of again expanding
or of warping or twisting under different conditions of climate and by which
sawdust and similar waste products resulting from wood working can be recon-
structed into a material resembling hard wood which may be employed as a
substitute therefor in making mauy articles.
In compressing wood it has hitherto so far as we are aware been compressed in
a cold state or after it has been treated with steam we find however that when
compressed cold the resins and gums are not firmly set and when treated with
steam a certain amount of moisture is retained in the pores of the wood which
when drying out renders it liable to warp and by experiment we also find that if
compressed while heated to a high temperature by dry heat that the natural resins
or gums become softened and are evenly distributed throughout the mass and on
becoming cool again retain the fibres of the wood in the position into which they
have been pressed.
The wood to be compressed is placed in a hot mould so constructed that it is
capable of being heated up to a temperature of 250° to 300° F. At this heat the
wood becomes more plastic and the gums or resins naturally contained in the wood
are melted or reduced to a liquid or semiliquid condition. The wood is allowed
to remain in the mould with a very slight or low pressure exerted upon it until it
is heated throughout or until all the resins and gums therein are softened.
Pressure is then applied gradually until the maximum pressure say of from
8 to 10 tons per square inch has been applied according to the density of material
required.
The press is constructed with double rams so that the pressure can be equally
applied to both sides of the material.
While the maximum pressure is still maintained the mould is cooled by water or
otherwise until the temperature has been reduced to 60° or 70° and the pressure is
not relieved nor the wood removed until the gums and resins have had time to reset
hard again.
We can in a similar manner rebuild or reconstruct solid pieces of wood by
compressing sawdust or other waste material from wood working in conjunction
with an added proportion of gums resins or other suitable agglutinants with or
without solvents. The waste products are mixed with the gums or resins preferably
in a dry state and placed in the moulds and compressed while heated to a high
temperature and then cooled.
The products can be sawn cut turned or otherwise worked like hard wood and
can also be coloured or stained either previously to or after the compression as
desired.
The moulds may be made of any design or pattern or any special shape.

page_text: We are aware that wood has been compressed before to a great density and
such per se does not constitute our invention.
Dated this 16th day of March 1896.
W. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Compressing Wood, and Utilizing Certain Waste
Products therefrom.
We, ALEXANDRE DE PONT, of Hest Bank, Lancaster, in the County of
Lancaster, Manufacturer, and SILVIUS DE PONT, of Bare, Lancaster, aforesaid,
Manufacturer, 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 :-
This invention relates to a process for compressing natural wood to any required
density which will render or leave the wood so treated incapable of again expanding
or of warping or twisting under different conditions of climate and by which sawdust
and similar waste products resulting from wood working can be reconstructed into
a material resembling hard wood which may be employed as a substitute therefor
in making many articles.
In compressing wood it has hitherto so far as we are aware been compressed in
a cold state or after it has been treated with steam we find however that when
compressed cold the resins and gums are not firmly set and when treated with
steam a certain amount of moisture is retained in the pores of the wood which when
drying out renders it liable to warp and by experiment we also find that if com-
pressed while heated to a high temperature by dry heat that the natural resins or
gums become softened and are evenly distributed throughout the mass and on
becoming cool again retain the fibres of the wood in the position into which they
have been pressed, and in this our invention essentially consists.
In the annexed drawing we have illustrated as an example a suitable form of
hydraulic press in which to carry out our invention.
This press is constructed with a mould A capable of being heated to a
temperature of 250° to 300° F. and double rams B and pressing plungers C which
enter the mould A from opposite sides so that the pressure can be applied equally
to both sides of the material. Any other convenient form of press however may
be employed.
The wood to be compressed is placed in the mould A and heated to about 250°
or 330° F. without the application of steam or vapour. At this temperature the
wood becomes more plastic and the gums or resins naturally contained therein
are softened or reduced to a liquid or semi-liquid condition. The wood is allowed
to remain in the mould with a very slight or low pressure exerted upon it until
it is heated throughout or until all the resins and gums therein are softened.
Pressure is then applied gradually until the maximum pressure say of from
8 to 10 tons per square inch has been applied according to the density of material
required.
While the maximum pressure is still maintained the mould is cooled by water
or otherwise until the temperature has been reduced to 60° or 70° and the pressure
is not relieved nor the wood removed until the gums and resins have had time to
reset hard again. Instead of cooling by water the cooling may be allowed to take
place more gradually the pressure being maintained until the gums and resins
have set.

page_text: We can in a similar manner rebuild or reconstruct solid pieces of wood by
compressing sawdust or other waste material from wood working in conjunction
with an added proportion of gums resins or other suitable agglutinants with or
without solvents.
For this purpose we prefer to use resin, shellac, copal or other similar gums
either separately or mixed. At present we consider the best results may be
obtained by mixing these three bodies together in about equal proportions and
adding the same to the sawdust (or other wood refuse) in the proportion of from
20% to 30%. These materials may be ground or pulverised and mixed with the
sawdust or wood refuse in a dry state and then transferred to the mould in which
they are softened or liquified by the heat applied. Or they may first be dissolved
in methyl turpentine, benzine or other suitable solvent and then mixed with the
sawdust or wood refuse and when dry compressed. In either case the compound is
compressed in a mould when heated to a temperature of 250° to 300° F. or more
and subjected to a pressure of about 8 to 1 tous per square inch gradually applied.
The material is cooled before the pressure is relieved to allow the gums to set.
The products can be sawn cut turned or otherwise worked like hard wood and
can also be coloured or stained either previously to or after the compression as
desired.
The moulds may be made of any design or pattern or any special shape.
We are aware that wood has been compressed before to a great density and
such per se does not constitute our invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be applied we declare that what we
claim is :-
1. The process of compressing wood to increase its density which consists in
subjecting the wood to an equal pressure from both sides whilst it is maintained at
a high temperature sufficient to soften or liquify the gums therein and retaining
such pressure until it is cool and the gums have set substantially as described.
2. The process of constructing or manufacturing a product resembling wood
which consists in mixing with or adding to sawdust or wood refuse a quantity of
gums resins or other suitable agglutinants either in a dry state or dissolved and
subjecting the compound to a great pressure when subjected to a temperature
sufficiently high to soften or melt the gums or resins employed substantially as
described.
Dated this 8th day of Decembar 1906
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.