A NEW PROCESS FOR EXTRACTING TANNIC ACID AND DYE-WOOD PIGMENTS FROM WOOD OR BARK OF CHESTNUTS, OAKS, OR DEALS, AND DYE-WOODS
Year: 1880

page_text: LETTERS PATENT to Henry Palm, Civil Engineer, of the Firm Michalecki &
Co., 1, Burgring, Vienna, Austria, Civil Engineers and Patent Agents, for
an Invention of "A NEW PROCESS FOR EXTRACTING TANNIC ACID AND
DYE-WOOD PIGMENTS FROM WOOD OR BARK OF CHESTNUTS, OAKS, OR DEALS,
AND DYE-WOODS." A communication from Doctor Otto Kohlrausch, of Vienna,
Austria.
PROVISIONAL SPECIFICATION left by the said Henry Palm at the Office
of the Commissioners of Patents on the 13th February 1880.
HENRY PALM, Civil Engineer, of the Firm Michalecki & Co., 1, Burgring, Vienna,
Austria, Civil Engineers and Patent Agents. "A NEW PROCESS FOR EXTRACTING
TANNIC ACID AND DYE WOOD PIGMENTS FROM WOOD OR BARK OF CHESTNUTS,
OAKS, OR DEALS, AND DYE WOODS." A communication from Doctor Otto
Kohlrausch, of Vienna, Austria.
1
20
The Invention consists in reducing (cleaving, breaking, sawing, &c.) the wood or
bark destined for the extraction of tannic acid or pigments to small pieces (about
1/2 to 3 inches long, /. to 2 inches broad, and 1/2 to 1½ inch thick) placing the said
pieces in closed vessels of copper, wood, enamelled iron or other suitable material,
and treating them with water (of 20 to 75° Centrigrade) and under pressure so as
to extract the tannic acid or pigments, the differont vessels forming a continuously
working battery, and being connected with one another by pipes, which may be
heated if desired.
If, for instance, the battery consists of twelve vessels, pure water, arriving under
pressure, is caused to enter the first vessel, where the process begins, and is continued
until the densities of the liquids inside and outside the wood or bark cells are
equalized. Subsequently the liquid is caused to pass from the first into the second
vessel, where the tannic acid or pigment solution will become more concentrated.
From the second vessel the liquid passes into the third, and so on up to the eleventh
vessel, where the concentration of the liquid is almost equal to that in the cells of
the raw material. During that time pure water has been supplied to the first
vessel, so that the wood mass contained in it has become exhausted and may be

page_text: discharged. Pure water is now admitted to the second vessel, and the twelfth
vessel filled with raw material. Afterwards the extracted liquid is made to pass
into the twelfth vessel, the first vessel is filled with raw material, the second vessel
discharged, and pure water caused to flow into the third vessel, and so on in such
a manner that the contents of 10 vessels are continuously subjected to dialysis.
The necessary temperature of the water may be maintained by providing the
connecting pipes with heaters of any suitable construction.
The extract so obtained may be further concentrated in vacuum pans and filled
in barrels, or it may be employed directly for the manufacture of leather or for
dyeing.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Palm in the Great Seal Patent Office on the 13th August
1880.
HENRY PALM, Civil Engineer, of the Firm of Michalecki & Co., 1, Burgring,
Vienna, Austria, Civil Engineers and Patent Agents. "A NEW PROCESS FOR
EXTRACTING TANNIC ACID AND DYE WOOD PIGMENTS FROM WOOD OR BARK
OF CHESTNUTS, OAKS, OR DEALS, AND DYE WOODS." A communication from
Doctor Otto Kohlrausch, of Vienna, Austria.
The wood destined for the oxtraction of tannic acid or pigments is not rasped, as
has been the case heretofore, but is comminuted by cleaving and breaking, or
sawing or stamping into small pieces ('/, to 3 inches long, /, to 2 inches broad, and
/ to, inch thick). These pieces of wood are then filled into a battery of 5 to 15
closed vessels of suitable form and size, preferably made of copper, wood, enamelled
iron, or other convenient material not liable to be attacked by tannic acid. The
wood is subjected to dyalisis by causing water to flow, under a pressure of about
one and three fourth of an atmosphere, into the first vessel. The water before
entering the vessel may be heated up to a temperature of from 20° to 75° Celsius
(68 to 167° Fahrenheit).
Now, according to the law of dyalisis, the liquid tannic acid or pigment contained
in the juice of the cells will first pass through the permeable cell-pellicles into the
surrounding water, and afterwards, when the solid tannic acid or pigment deposited
in the cells has been dissolved by the water penetrated into the cells, this dissolved
tannic acid or pigment will likewise pass into the surrounding water. This dyalitic
process continues until the densities or concentrations of the contents of the cells
and of the surrounding water are equalized, after which the liquid passes through a
connecting pipe provided with a heating apparatus of any convenient form from
the first into a second vessel, and fresh water is let a second time into the first
vessel. The above described process is repeated, the dyalised liquids are caused to
pass from the 2nd into the 3rd, and from the first into the 2nd, while fresh water
enters the first vessel. A heating apparatus, consisting of a steam pipe discharging

page_text: into the connecting pipes between the vessels, allows of maintaining the liquids at
a constant temperature of 20° to 75° Celsius. The vessels are in their form not
essentially different from the "diffuseurs" employed in the manufacture of sugar;
they are hermetically closed so as to prevent the tannic acid from being converted
by its contact with air into gallic acid (C7 H O) and ellagacid (C" H O³).
The dyalitic process is repeated in each vessel up to the last but one, viz., to the
11th, supposing the battery to consist of 12 vessels. Whilst the contents of the
last vessel but one are subjected to dyalisis, the first vessel is stopped, and its
exhausted contents are discharged. Now fresh water is let into the second vessel,
and the 12th vessel filled with raw material. After this operation has been
completed, the extracted liquid is made to pass into the 12th vessel, vessel 1 is
filled, vessel 2 discharged, and fresh water caused to enter vessel 3, and so on, so
that the contents of 10 vessels (if the battery consists of 12 vessels) are at the
same time subjected to dyalisis, tannic acid or pigment being continuously drawn
off, whilst one vessel is being filled and another discharged. The oxtract is then
inspissated in vacuum pans and filled into barrels, or it may be directly employed
in the manufacture of leather..
CLAIM.
The application of the principle of dyalisis for extracting tannic acid or dye
O wood pigments from the wood or bark of trees rich in tannic acid or colouring
matter, substantially as set forth in the foregoing Specification.
In witness whereof, I, the said Henry Palm, have hereunto set my hand and
seal, this Second day of August, A.D. 1880.
ITRAT