Improvements in Tanning, and Apparatus for that Purpose.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Tanning, and Apparatus for that Purpose.
1, EUGENE WORMS, Operative, of 51, Rue de Provence, Paris, France, do
hereby declare the nature of this invention to be as follows:-
This invention relates to means of tanning hides in a rapid and effective manner
by subjecting them while in agitation to the action of electricity and tanning
liquors under moderate heat. The apparatus for this purpose consists of a
revolving barrel, which may be of wood and has arranged over its internal
periphery a number of conducting wires connected with an external commutating
switch provided with brushes which are connected through an rheostat with a source
of electricity. The barrel is furnished with a side opening for introducing and
removing the hides, which can be tightly closed, with a thermometer and pressure
gauge, and with a safety valve. One of its trunnions is tubular and is connected
by a union to a pipe by which tanning liquor can be fed or withdrawn. The
barrel being charged with hides and enough tanning liquor to cover them, is caused
to revolve until the contents become heated to about 15° C. whereupon
an electric
current is switched in. This has the effect of promoting the tanning action, the
tanning liquor taking the place of the fluid in the pores of the hides. After about
half the time required for tanning, the electric current is switched off, additional
tanning liquor is introduced and the agitation movement continued until the hides
are completely tanned. The total time occupied is from 24 to 48 hours for light
hides and 60 to 105 hours for heavy hides.
. Dated this 16th day of October 1895.
ABEL & IMRAY,
Agents for the Applicant.
I, EUGENE WORMS, Operative, of 51 Rue de Provence, Paris, France, do
bereby 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 :-
In the ordinary process of tanning the hides are brought in contact with materials
such as bark, containing tannin, under which conditions the penetration of the
tannin is very slow, so that the process of tanning hides into leather occupies
months.
According to more recent processes it has been endeavoured to shorten the
duration of the process by forcing the tannin into the hides by means of
compressed air, or by using acids and other corrosive products, or by the use
of electric currents.
All these processes have however proved more or less imperfect, and present
numerous inconveniences in their application.
My invention relates to an improved process which is capable of being practically
carried out in a very economical manner, and is based on new and rational
principles.

page_text: I have observed that heat exercises a very great influence on the depilated
hides, and that under its action swelling is produced whereby the pores are
opened.
I have also found that the tannin liquors when raised to a certain temperature
are assimilated more readily by the gelatine of which the hides are mainly
constituted.
My improved process is therefore based on the employment of heat for
accelerating the tanning process, such heat being economically produced for the
purpose and a detrimental degree of heating being guarded against.
Another problem, required however to be solved; in order that the tannin might
penetrate more readily into the hides and fill out the cells of which the tissue is
composed, it was indispensably necessary to previously remove the water contained
in such cells.
The improved process therefore consists of three features: Firstly effecting in
a practical manner the simultaneurs heating both of the hides and of the tannin
liquor; secondly, regulating the extent of such heating by practical means;
thirdly, removing the water contained in the organic tissue of the hides.
For carrying out this triple operation 1 employ a closed vessel within which
is produced the requi-ite heat in a gradual manner by the regular agitation, un lor
exclusion of the air, of the hides and liquids introduced therein, the xidation of
the tannin liquors being at the same time prevented.
I construct the said vessel by preference of a cylindrical turm, and provide it with
the necessary appliances for regulating the internal temperature and the simultaneous
extraction of the water from the cells of the hides.
The cylindrical vessel is mounted with hollow trunnions upon supports, one
of which trunnions is provide with a safety valve, boudel to the maximum
pressure to which the interior of the vessel is to be subjected, so that any excess
of gases produced therein will escape through the valve. The vessel is provide
with a pressure gauge and a thermometer for bserving both the temperature and
the pressure.
For exhausting the cells of the hides of water, I employ an electric current, by
means of which the water is decompensed into oxygen and hydrogen, the space-
taken op by the water being at once occupied by the tannin liquor.
For this purpose provide on the inner surface of the cylindrical vessel
conducting wires the ends of which are connected to contact rings on the outer end
surfaces of the vessel, which rings are put in connection with the circuit of a current
generator by tacan of brushes.
The vessel has an opening closed by a door, through which the hides are
introduced and removed.
The necompanying drawing shews the construction of the apparatus which
employ by preference for carrying ont my invention.
Fig. 1 shows an end view.
Fig. 2 a side view partly in section.
A. is the cylindrical drum preferably made of wood, having an opening B for
the introduction and removal of the hides, closed by a door C. D is a pipe
through which the tanning liquor is introduced into the drum, this being effected
through one of the hollow trunnions, su as not to require to stop the rotation of
the drum. The other trunnion is provided with a safety valve a opening outwarls
under excessive pressure of the gases in the drum. E E are copper rings to which
are attached the ends of the conducting wires fixed on the inner surface of the
drum. F F are brushes hearing against the surfaces & b' of the rings E E' and
connected to the circuit of a current generator,-G is a pressure gauge, H is a
thermometer. To the end face of the drum is fixed a toothed ring M gearing with
a pinion N on the driving shaft O having fast and loose belt pullies P. Q.
The intensity of the electric current is regulated by means of resistances R which
are included in or excluded from the circuit by means of a switch.
In operating with this apparatus I introduce in the first instance into the drum

page_text: sufficient water for entirely submerging the hides therein. This water is converted
into tanning liquor by adding thereto tannin extract of 20° Bé. in the proportion
of 50 per cent. of the weight of the hides to be tanned and mixed with 5 per cent. of
such weight of a vegetable solvent. The hides having been couched in this liquor
the opening is closed and the drum is rotated. By the resulting agitation of the
hides and liquor under exclusion of the atmosphere, the temperature will gradually
rise: as soon as the thermometer indicates a temperature of 15° C., I close the
electric circuit so as to subject the hides to the action of the electric current, which
will operate most effectually when the pores of the hides have been opened by the
above temperature.
When the action of the current has been continued for a length of time equal
to one half the duration of the tanning process, the circuit is broken, and a
fresh quantity of tannin extract equal to that first introduced is fed in through the
pipe D.
The temperature in the drum is maintained between 25° and 30° C., being
regulated by opening the safety valve a more or less.
At the end of from 24 to 48 hours for all kinds of light hides, and from
60 to 105 hours for medium and heavy hides, the apparatus is stopped and the
gases are allowed to escape after which the door is opened and the tanned hides
which will be found to be in perfect condition are reinoved.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described process of tanning hides by gradually and moderately
heating them and the tanning liquor within a closed vessel excluding air and
at the same time expelling the water from the cells of the hides by electrically
decomposing it.
2. Apparatus for carrying out the process above referred to consisting of a closed
revolving drum with hollow trunnions, a safety valve upon one of the trunnions and.
appliances for subjecting the hides within the drum to the action of the electric
currents, substantially as described.
n.
J
1800
ABEL & IMRAY,
Agents for the Applicant.