Improvements in Tannic Extracts, and in Apparatus for the Manufacture thereof.
Year: 1898

page_text: MOTIONAL DIMITIVATION.
Improvements in Tannic Extracts, and in Apparatus for the
Manufacture thereof.
I, ADOLPHE RAINARD, of Près le Marché, Nantes, in the Republic of France,
Inventor, do hereby declare the nature of this invention to be as follows:-
The object of this invention is improvements in tannic extracts and in
apparatus for the manufacture thereof.
These extracts are generally obtained by putting bruised bark or wood into
tepid water by means of diffusion a liquid is obtained of 4° Baumé (density) this
liquid is then clarified by means of substances containing sulphuric acid or oxalic
acid and then concentrated in an evaporator of 20° Baumé.
The tannic extracts thus obtained are always acid and contain from 20 to
23% of serviceable matter.
Into
In the manufacture which forms the object of this application, the bruised bark
or wood is always treated in diffusing vessels: the liquid at 4° Baumé then
passes into a clarifying vat containing an agitator operated by any suitable motive
power and a worm in which the steam for heating the liquid circulates.
this vat a quantity. of nicotine is introduced, this quantity being determined by
experience according to the nature of the liquid. The mixture precipitates the
foreign or extraneous substances.
Almost immediately after the introduction of the nicotine, a decoction of
filtered and sifted pure linseed is poured into the vat in the proportion of about
4 kilogrammes of linseed to 100 litres of water and then boiled for fifteen
minutes.
The whole then is vigorously agitated by an agitator and allowed to stand. By
this means the organic matters are precipitated to the bottom of the vat under
the action of the nicotine whilst the tannic extract assumes the velvet like and
oily appearance appreciated by manufacturers.
The extract is then forced by means of any kind of pump up to a filter placed
at a certain height, and from this filter it is conducted to the concentrating
apparatus placed below the same. This evaporating apparatus is composed of
preferably three closed vessels, arranged one somewhat higher than the other
(step fashion) and on suitable supports. Each of the vessels contains a worm in
which the steam circulates; the same steam serving for the 3 vessels and then
escaping. Each of the vessels is connected with the adjoining one by means of
a tube which is furnished with a cock, the last vessel being provided with a
discharge cock for running off the concentrated extracts into the receivers or
transport casks.
The extract leaving the filter enters the first vessel, where the temperature is
highest and in which it acquires a density of 10° Baumé; it then passes into the
second vessel where it reaches 16° Baumé finally into the third vessel where it
attains a density of 20° Baumé.
The operation is carried on so as to be continuous that is to say, the three
vessels always contain extract at different degrees of concentration.

page_text: The vapours given off in the three vessels are drawn off by suction, through the
medium of tubes which connect the upper parts of the same, by means of an air
pump and are condensed in a surface condenser arranged on the suction tube
branching off from the upper part of the third vessel, which enables the particles
of tannin that may have been carried off, to be collected, this being to the
advantage of the extract under treatment.
The introduction of the nicotine may be effected either before or after the con-
centration; if done before this last operation, a further quantity can be added
after, if necessary.
Dated this 20th day of Santambor 1898
S. S. BROMHEAD,
Agent for Applicant,
171, Queen Victoria Street, London, E.C.
Improvements in Tannic Extracts, and in Apparatus for the
Manufacture thereof.
I, ADOLPHE RAINARD, of Près le Marché, Nantes, in the Republic of France,
Inventor, 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:
The object of this invention is improvements in tannic extracts employed in
tanning leather and in apparatus for the manufacture thereof.
These extracts are generally obtained by putting bruised bark or wood into
tepid water in order to extract the tannic or tannic properties which they contain.
By means of diffusion a liquid is obtained of 4° Baumé (density). This liquid is
then clarified by means of substances containing sulphuric acid or oxalic acid,
in order to precipitate the salts and organic matter which it contains, and is then
concentrated in an evaporator until it attains a density of 20° Baumé.
The tannic extracts thus obtained are always acid and contain from 20 to
23 per cent. of serviceable matter.
According to my invention the tannic extracts always obtained by diffusion, are
clarified without employing acids, and contain nearly 27 per cent. of useful
matter, after one concentration of 20° Baumé. They thus possess properties of
incontestable value for the tanning of leather and they also impart to leather a
soft velvety finish, much desired by tanners. Morcover by my invention the con-
centration of the clarified tannic extracts is obtained under such conditions that
the usual cost of this part of the manufacture is reduced to a minimum.
It is therefore easy to see that my invention relates to a method of treatment
which produces a tannic extract possessing special properties and also to apparatus
for concentrating the extract, and further to other details indicated in the follow-
ing description.
In the accompanying drawings Fig. 1 shows an elevation of the entire apparatus
employed for producing tannic extract according to my invention.
Fig. 2 shows an elevation in vertical section of the concentrating apparatus.
Fig. 3 shows a plan view of the same.
Referring to Fig. 1, A, represents one of the diffusing tanks, in which the
crushed wood, or bark, and tepid water, are placed together; B, is one of the
vats, into which the tannic extract at 4° Baumé, coming from the tanks A, is
poured, for the purpose of being clarified; C is a pump of any kind for forcing

page_text: the clarified extract into a filter D; E is the evaporating apparatus, to which the
clarified, and filtered, tannic extract, is conveyed, in order to be concentrated to
20° Baumé; and F' is one of the casks into which the clarified, filtered and con-
centrated tannic acid is poured, for conveyance to the places where it is to be
used.
There is nothing peculiar in the diffusing tanks; they are constructed and act
in the ordinary manner.
The clarifying vats are made of wood, and are provided, in each case, with a
worm, and an agitator, of any kind. Steam is caused to circulate in the worm,
so as to raise the temperature of the tannin extract coming from the diffusion
tanks.
When this temperature is, for example, and preferentially, between 55° and 70°
Centigrade, the heating is suspended, nicotine is poured into the tannic extract
(1 litre of nicotine, for example, for 4000 litres of tannic extract) and the
mixture vigorously stirred. Under the action of the nicotine, all the organic
matters, or substances foreign to the tannin, are precipitated to the bottom
of the vat, but the extract is deprived of its syrupy or varnish like appearance.
esteemed by tanners.
It should be remarked that the figures given in the preceding paragraphs
are not absolutely fixed: nicotine as experience shows, precipitates extraneous
matters from a tannic extract at all temperatures and at any degree of density,
the quantity to be introduced being determined by the nature of the extract.
The nicotine may be introduced before, during, or after concentration of the
tannic extracts, and after being introduced before the concentration, it may, in
certain special cases, be introduced again afterwards.
Almost immediately after the first introduction of nicotine, a filtered or sifted
decoction of raw linseed is poured into the clarifying vat (for example, 4 kilo-
grammes of linseed, to 100 litres of water, and boiled, say, for fifteen minutes)
the whole being vigorously stirred and allowed to stand. Organic matters, or
extraneous substances are precipitated under the action of the nicotine, whilst
the tannic extract assumes the velvety or varnish like appearance which it should
possess.
The pump C conveys the clarified extract from the vat B into the filter D, the
active material in which consists of straw and sand arranged in alternate layers.
The extract is conveyed from this filter to the concentrating apparatus, which
I will now describe with reference to Figs. 2 and 3.
In these figs. G. H and I are three closed vessels, connected together at the
top, by means of the tubes g and h, and at the bottom by the tubes i and j
respectively furnished with the cocks and ¹. The case G communicates with
the filter D previously mentioned, by the tube k, whilst the concentrated extract
is run off from the vessel I through the tube furnished with a cock l¹. In the
three vessels are worms J, K and L, respectively connected by the opening or
closing tubes m, n which are furnished with taps. The steam enters at o and
passes out at p. Finally the vessel I is surmounted by a surface condenser
formed by the circulation of water in the annular space M surrounding the
tube g connected with an exhaust pump P.
The extract to be concentrated, is introduced at a strength of 4° Baumé in
the vessel G by means of the tube K. Under the action of the heat generated
by the worm J, it is rapidly carried to 10° Baumé. From the vessel G, it is
conveyed, by opening the cock ¹, into the vessel H where it reaches a strength
of 160 Baumé. From the vessel H, it is conveyed, through the opening of the
cock into the vessel I where it reaches a strength of 20° Baumé.
The operation is carried on so as to be continuous, that is to say, the three
vessels always contain extract at different degrees of concentration. It will be
observed that the same steam circulates in the three vessels; this steam is hottest
in the vessel G and coolest in the vessel I; it acts as is seen, more powerfully in
the first vessel than in the last. In the last the extract only simmers.

page_text: The vapours given off from the three vessels are drawn up by the pump; they
are condensed in the surface condenser M, whereby the tannin which may have
been carried along with them can be collected, to the benefit of the extract under
treatment.
The tannin when it leaves the third vessel, is thus concentrated to 20° Baumé,
and, being analysed, is found to contain 27% of serviceable matter, whilst the
extract obtained by existing processes contains but 20 to 22% and at the same
density.
The extract obtained presents special advantages: on the one hand, it is not
acid and, on the other, it is richer in serviceable matter. These two advantages
distinguish it in a marked degree from similar products now found in commerce.
So much having been explained, it must be understood: that I do not confine
myself entirely to the proportions mentioned above, which have been given only
by way of example and which consequently, are variable according to the nature
of the substances employed, and that I claim full latitude in regard to the precise
forms and dimensions to be given to the apparatus made use of.
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:
1. In the manufacture of tannin extracts, the process consisting in the use of
nicotine for clarifying the extracts obtained by diffusion; the said nicotine being
employed, for example, in the proportion of 1 litre of nicotine for 4000 litres
of extract, and introduced into the extract when the latter is at a temperature
between 55° and 70° Centigrade, for the purpose of precipitating, without the
assistance of any acid, the organic matters or extraneous substances, which may
be in the tannic extract. This nicotine, however, is capable of employment at
any temperature and any degree of density, and the quantity of the same to be
introduced is determined by the nature of the extract, and the introduction of
the nicotine can be effected before, during or after the concentration, in the
manner specified, and herein set forth.
2. In the manufacture of tannic extracts, the employment of nicotine in com-
bination with a decoction of linseed, for the purpose, on the one hand, of pre-
cipitating all the organic, or extraneous matter, which is in the said extracts, and
on the other, to impart to the extracts thus clarified, an oily, fatty or velvety
appearance, in the manner specified, and herein set forth.
3. In the manufacture of tannic extracts, the employment of an evaporator, by
means of which the said extracts can be concentrated, in a continuous manner
from 4° Baumé to 20° Baumé, the said evaporator being composed of three
vessels connected together on the one hand by means of a single heating pipe, or
worm, running from the one to the other, and proceeding from a steam generator,
and, on the other hand, by means of a suction tube, in communication with an
air pump, the whole acting in the manner and for the purpose indicated, as
herein described and set forth.
4. A process of manufacturing tannic extracts consisting in obtaining
extract of 4° Baumé by diffusion in the ordinary manner; clarifying the same
by means of nicotine; imparting to it the requisite velvet like characteristic, by
the addition, shortly after the clarifying operation, of a decoction of linseed;
filtering the extracts thus clarified, and concentrating the same in a continuous
and methodical manner, by introducing steam at a temperature which is
diminished in proportion as the concentration is more complete, the whole as
herein described, and set forth.
5. In the manufacture of tannic extracts, the employment of a filter, consisting
of a vessel containing alternate layers of straw and sand, as herein described, and
set forth.
6. The arrangement as a whole, and in detail, of the evaporating apparatus

page_text: for the tannic extract, with reference to the accompanying drawing, as herein
described and set forth.
7. The combination of such evaporating apparatus with a suction pump and
a surface condenser, the said condenser being intended to keep the products of
condensation separate from the cooling liquid and in consequence to enable the
said products to be collected in the manner described, and set forth.
8. As a new commercial product, a tannic extract presenting the following
advantages:-namely of being free from acid, and of possessing, for example, at
a density of 20° Baumé, 27% of serviceable matter, whilst having a fatty or
velvet like appearance, the said product enabling leather to be tanned under the
most favorable conditions, substantially as described above and illustrated in the
accompanying drawings.
Doted this 23rd dow of Mo 1900