A Process for Clarifying or Decolorizing Tannic Extracts.
Year: 1892

page_text: Date of Application, 7th Dec., 1892
Complete Specification Loft, 5th Sept
1893 Accented 7th Dec.. 1893
PROVISIONAL SPECIFICATION.
A Process for Clarifying or Decolorizing Tannic Extracts.
We, ALCIME SINAN and HENRI SINAN, of Nantes, (Loire-Inférieure) in the
Republic of France, Merchants, do hereby declare the nature of this invention to
be as follows:-
This invention consists of à process for clarifying or decolorizing tannic
extracts.
Generally the manufacture of tannic extracts comprises the following operations,
namely
1. Extraction.
2. Evaporation or concentration.
3. Clarification or decolorization.
In carrying out our invention the two first operations do not differ from those
performed by other manufacturers and are only mentioned here because they form
an integral part of the manufacture and to give greater clearness to the description
which follows relative to the decolorization.
Tannic extracts are derived from bark, leaves, and wood shavings or chips.
The extraction is effected by maceration or infusion under heat or cold but
most advantageously under heat. The ooze obtained by maceration is then
introduced into heating apparatus where it is concentrated to a density of from
20° to 30° Baumé.
The products thus concentrated are suitable for commercial purposes but to
satisfy all the requirements of the tanning process they require to be clarified or
decoloured.
This last part of the manufacture which forms the essential feature of this
invention differs entirely from the clarifying or decolorizing processes hitherto
known.
The object of the clarifying or decolourizing operation is to free the tannic
extracts from colouring matters of a sirupy consistence which prevent them
penetrating the leathers. It greatly accelerates the tanning operation and further
allows of employing extracts for thin leathers without fear of colouring them. The
ooze being cooled on issuing from the heating apparatus is poured into a vat to
The decolourizing
undergo the treatment serving to clarify or decolour it.
materials employed for the tannic extracts are the same as those which serve for
other industrial products, namely, blood, glue, albumen or other suitable substance.
But the principal objection to the employment of these matters, notably blood, has
been the difficulty of causing them to intimately mix with the ooze owing to their
coagulation. To obviate this inconvenience some manufacturers introduce the blood
into the decoction first lowering the temperature to a degree below the point of
coagulation of the blood and afterwards raising it to the precise point of such
coagulation which on being produced causes the blood to be precipitated and carry'
with it the colouring matters.
According to our invention we operate as follows. To obviate the difficulty
resulting from the coagulation we previously dissolve the blood with bi-carbonate
of soda in a certain quantity of water heated to the desired degree after which it is
allowed to cool. We thus obtain a new product which does not act in the same
manner as the blood when acting alone. It may be poured into the ooze without it
being necessary to take any steps for varying the temperature for the purpose of
coagulating the blood. The ooze is almost completely cold, and even entirely cold,
This vat is covered with
if preferred, when it is poured into the decolourizing vat.
a sieve through the openings in which the solution containing the blood and the

page_text: bi-carbonate of soda is poured. Within the vat is a vertical shaft carrying several
hollow arms which shaft receives a slow rotary movement for effecting the mixture
of the solution with the ooze. The mixture being effected it is allowed to stand
and the blood carries to the bottom the colouring matters which are deposited
thereon. A little above this deposit is a cock which serves to draw off the clarified
liquid. The operation can be effected cold without the necessity of introducing
steam at any period throughout the operation.
Dated this 7th day of December 1892.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.
A Process for Clarifying or Decolorizing Tannic Extracts.
We, ALCIME SINAN and HENRI SINAN, of Nantes, (Loire Inférieure) in the
Republic of France, Merchants, 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 consists of a process for clarifying or decolorizing tannic
extracts.
Generally the manufacture of tannic extracts comprises the following operations,
namely:-
1. Extraction.
2. Evaporation or concentration.
3. Clarification or decolorization.
In carrying out our invention the two first operations do not differ from those
performed by other manufacturers and are only mentioned here because they form
an integral part of the manufacture and to give greater clearness to the description
which follows relative to the decolorization.
Tannic extracts are derived from bark, leaves, and wood shavings or chips.
The extraction is effected by maceration or infusion under heat or cold but most
advantageously under heat. The ooze obtained by maceration is then introduced
into heating apparatus where it is concentrated to a density of from 20° to
30° Baumé instead of to about 2° only as hitherto generally practised.
The products thus concentrated are suitable for commercial purposes but to
satisfy all the requirement of the tanning process they require to be clarified or
decolourized.
This last part of the manufacture which forms the essential feature of this
invention differs entirely from the clarifying or decolorizing processes hitherto
known.
The object of the clarifying or decolorizing operation is to free the tannic
extracts from colouring matters of a sirupy consistence which prevent them pene-
trating the leathers. It greatly accelerates the tanning operation and further
allows of employing extracts for thin leathers without fear of colouring them. The
ooze being cooled on issuing from the heating apparatus is poured into a vat to
undergo the treatment serving to clarify or decolourize it. The decolorizing
materials employed for the tannic extracts are the same as those which serve for
other industrial products, namely, blood, glue, albumeu or other suitable substance.
But the principal objection to the employment of these matters, notably blood, has
been the difficulty of causing them to intimately mix with the ooze owing to their
coagulation. To obviate this inconvenience some manufacturers introduce the
blood into the decoction, first lowering the temperature to a degree below the
point of coagulation of the blood and afterwards raising it to the precise point of
such coagulation which on being produced causes the blood to be precipitated and
carry with it the colouring matters.

page_text: According to, our invention we operate as follows. To obviate the difficulty
resulting from the coagulation we previously dissolve in nearly equal proportions.
the blood or other gelatinous or albuminous matter with bi-carbonate of soda in a
certain quantity of water heated to the degree necessary to obtain a complete
solution by injecting steam, the boiling lasting for about sixty minutes, after which
the solution is allowed to cool. The proportions which we have found to give good
results in practice are as follows, viz. -Blood or other gelatinous or albuminous-
matter, about one litre, bi-carbonate of soda about one kilogramme and water about
half a litre or sufficient to dissolve the bi-carbonate of soda. We thus obtain a
new product which does not act in the same manner as the blood when acting
alone. It may be poured into the ooze without it being necessary to take any
steps for varying the temperature for the purpose of coagulating the blood. The
ooze is almost completely cold, and even entirely cold, if preferred, when it is
poured into the decolorizing vat. This vat is covered with a sieve through the
openings in which the solution containing the blood and the bi-carbonate of soda is
poured. Within the vat is a vertical shaft carrying several hollow arms, which
shaft receives a slow rotary movement for effecting the mixture of the solution with
the ooze.
The mixture being effected it is allowed to stand and the blood carries.
the colouring matters to the bottom. A little above this deposit is a cock which.
serves to draw off the clarified liquid. The operation can be effected cold without.
the necessity of introducing steam at any period throughout the operation.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
In the process of clarifying or decolorizing tannic extracts―
1. Dissolving apart, in nearly equal proportions, blood or other gelatinous or
albuminous matter with bi-carbouate of soda in a certain quantity of water, the
temperature of which is raised by injecting steam to the point necessary for
obtaining a complete solution, the boiling lasting for about sixty minutes, after
which the solution is allowed to cool, substantially as set forth.
2. Pouring the solution into the ooze through a sieve on the decolorizing vat,;
the mixture taking place in a cold state without it being necessary to vary the
temperature during the mixing and decolorizing operations, substantially as set
forth.
3. Operating on ooze concentrated to a density of about twenty to thirty degrees.
Baumé substantially as set forth.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.