AN IMPROVED PROCESS OF AND APPARATUS FOR EXTRACTING TAN BARK AND OTHER VEGETABLE MATERIALS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by William Edward Newton at the
Office of the Commissioners of Patents, with his Petition, on the
28th February 1866.-A communication from abroad by Samuel White
Pingree, of Lawrence, in the State of Massachusetts, United States of
America.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature
of the said Invention for "AN IMPROVED PROCESS OF AND APPARATUS FOR
EXTRACTING TAN BARK AND OTHER VEGETABLE MATERIALS," to be as follows:-
This Invention is principally based on the use of steam in making extracts
from tan bark and other vegetable materials, and it consists in treating ground
tan bark or other material, first, with a weak extract or with water, whereby
the material is swelled, and after the first liquor has been drained off
treating it with steam, which penetrates the bark or other material and
prepares it for a second percolation with cold water or weak tan liquor or
other extract and a second treatment with steam, so that by the application of
the first washing the bark or other material is prepared for the action of
steam, whereby the soluble parts contained in the bark are softened and
brought in the best condition to give up their tannin or other substance to

page_text: be extracted to the second washing of cold water or weak tan liquor or other
The apparatus consists of a wooden or other vessel of sufficient
strength to sustain considerable pressure and provided with a tightly fitting
cover. This vessel may be divided by transverse partitions into a series of
compartments. A steam pipe connected with a boiler or the exhaust of a
steam engine extends over the entire length of the vessel, and branch pipes
lead therefrom down into the several compartments of the vessel. The bark
or other material to be extracted rests on slotted or perforated false bottoms,
and the branch pipes lead into boxes situated close to the perforated bottoms
of the several compartments of the vessel. These boxes are employed to
facilitate the introduction of exhaust steam, which in passing into them is free
to expand. The sides of the boxes are perforated with a large number of
holes, through which the steam passes out to the material to be extracted.
As the steam passes through the branch pipes into the boxes it expands, and
a partial condensation takes place both within the boxes and outside of the
same, and by this partial condensation combined with the rapid expansion of
the steam as it reaches the boxes all back pressure on the piston of the
engine is avoided. If the steam be taken directly from a steam generator,
the boxes can be dispensed with, although they serve in all cases to disseminate
the steam evenly through the material to be extracted. The tan bark or
other material to be extracted, which may first be ground, is placed in a tub
and steeped in water or weak liquor for three to six hours. By the action of
the liquid the bark or other material is softened and swelled, and a portion of
its strength is extracted. The liquor thus obtained is drained off, and steam
is admitted into one or more of the compartments. After the bark has been
thoroughly heated by the action of the steam the vessel is again filled with
cold water and the tan bark allowed to steep for 30 minutes, and then it is
heated a second time and again washed with cold water or weak liquor.
After draining off the last liquor the bark may be again heated and washed
until all the strength is taken out.