Improvements in or connected with Tanning Hides and Skins.
Year: 1893

page_text: Complete Specification Left, 31st May, 1894-Accepted, 6th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements in or connected with Tanning Hides and Skins.
I, JACQUES DURIO (son of Joseph Durio) of Madonna di Campagna, Turin in
the Kingdom of Italy, Tanner do hereby declare the nature of my invention to be
as follows:-
This invention relates to a process for rapidly tanning hides and skins, without
employing water in the operation in which the tanning is actually performed. The
process consists in preparing the hides and skins in such a manner as to enable
them to resist the action of pure tannic extract and in the successive application of
the said extract in the liquid condition as sold in the trade without diluting it with
water or with weak tannic solutions.
In carrying out the said process in practice the hides or skins are prepared as
next hereinafter described.
The hides or skins are treated with lime in the usual manner.
They are unhaired and fleshed.
They are then cleaned to remove the lime.
They are subjected to the action of a bath of granular hydrate of soda or other
equivalent chemical agent in solution.
They are freed from the absorbed hydrate by placing them in a centrifugal
machine or by other suitable means.
They are subjected to a fresh bath of cold water.
They are again cleaned and a portion of the water which they have absorbed is
afterwards removed by pressure or otherwise.
They are subjected in a centrifugal apparatus or otherwise to the action of a
solvent of grease.
The hides or skins thus prepared are placed in a travelling or movable closed
vessel into which liquid tannic extract in the condition in which it is sold in the
trade and without diluting it either with water or with weak tannic solutions is
introduced in proportions increasing at first and afterwards diminishing. The
vessel must be mounted on wheels or must be movable or be so arranged that the
hides or skins which it contains can be continually rotated or agitated.
It is immaterial whether the extract be hot or cold and there is no necessity for
transferring the hides or skins from one apparatus to another or for drawing off the
extract contained in the apparatus during the operation and introducing another
supply of extract in the place of that which has been removed.
The quantity of extract to be employed is not greater than that which would be
employed in tanning the same quantity of hides or skins in the ordinary way and
which is usually diluted with water or with weak tannic solutions. The rotary
motion or agitation of the hides or skins is regulated according to the quality and
thickness the minimum time occupied being about two hours and the maximum
about 24 hours. The operation being completed as herein before described the
hides or skins are effectually tanned.

page_text: The system of rapid tanning by rolling or agitation of the hides and skins
without diluting the tanning extract with water or weak tannic solutions and the
elimination as far as possible of all the water, in addition to greatly reducing the
time occupied in the tanning process also presents the following advantages
namely.
It is capable of being used in any locality because the disadvantages are obviated
which exist in certain places where the water by reason of certain substances which
it contains is liable by combining with the tannin to prevent delay or prejudice the
tanning.
It produces a useful commercial result greatly superior to that which is obtained
by the processes heretofore employed.
Dated the 6th day of September 1893.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.
COMPLETE SPECIFICATION.
· Improvements in or connected with Tanning Hides and Skins.
I JACQUES DURIO (son of Joseph Durio) of Madonna di Campagna Turin in
the Kingdom of Italy Tanner do hereby declare the nature of my 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 relates to a process for rapidly tanning hides and skins without
employing water in the operation in which the tanning is actually performed. The
process consists in preparing the hides and skins in such a manner as to enable
them to resist the action of pure tannic extract and in the successive application of
the said extract in the liquid condition as sold in the trade without diluting it with
water or with weak tannic solutions.
In carrying out the said process in practice the hides or skins are prepared as
next hereinafter described.
The hides or skins are treated with lime in the usual manner.
They are unhaired and fleshed.
They are then cleaned to remove the lime.
They are subjected to the action of a bath of granular hydrate of soda or other
equivalent chemical agent in solution. The strength.of the solution may vary say
from 3 to 12 kilogrammes of hydrate to 100 kilogrammes of hides according to the
method of treating the hides with lime and the nature of the water employed
whether it be more or less calcareous. The hydrate should be diluted with water
amounting to four times the weight of the hides.
They are freed from the absorbed hydrate by placing them in a centrifugal
machine or by other suitable means.
They are then subjected to a fresh bath of cold water and again cleaned and a
portion of the water which they have absorbed is afterwards removed by pressure
or otherwise.
They are subjected in a centrifugal apparatus or otherwise to the action of a
solvent of grease.
The hides or skins thus prepared are placed or suspended in a closed drum or
vessel into which liquid tannic extract (in the condition in which it is sold in the
trade and without diluting it either with water or with weak tannic solutions) is
introduced in small quantity at first the quantities introduced at intervals being
gradually increased until the tanning process (which is very rapid at first) gets slow
whereupon the quantities of tannic extract introduced are gradually reduced until
the tanning process is completed. The object of introducing the tannic extract in
small and increasing quantities at first is to prevent too sudden contact thereof with
the hides and the pores of the hides from being obstructed by too great a volume

page_text: of the extract at the commencement which would retard the tanning process and as
the said tanning process is more rapid at the commencement than it is later on the
quantity of tannic extract introduced is gradually reduced towards the completion
of the process. The vessel may be mounted on wheels and receive a continuous
rotary motion or a reciprocating or other motion so that the hides or skins which
it contains will be continually rotated or agitated in the tannic extract.
It is immaterial whether the extract introduced be hot or cold and there is no
necessity for transferring the hides or skins from one apparatus to another or for
drawing off the extract contained in the apparatus during the operation and intro-
ducing another supply of extract in the place of that which has been removed as is
the case in the usual process of tanning.
The quantity of extract to be employed is not greater than that which would be
employed in tanning the same quantity of hides or skins in the ordinary way and
which is usually diluted with water or with weak tannic solutions. The continuous
or reciprocating rotary motions may be given to the drum or vessel containing the
hides or skins by any suitable means to effect the agitation of the said hides or
skins in the tannic extract. The speed and duration of the motions given to the
drun or vessel is regulated according to the quality and thickness of the hides or
skins under treatment the minimum time occupied being about two hours and the
maximum time about twenty four hours. The operation being completed as
hereinbefore described the hides or skins are effectually tanned.
The system of agitating the hides or skins in a vessel containing the tanning
extract undiluted with water or weak tannic solutions and the elimination so far as
possible of the water from the hides before they are placed in the tauning vessel in
addition to greatly reducing the time occupied in the tanning process also presents
the following advantages namely:-
It is capable of being used in any locality because the disadvantages are obviated
which exist in certain places where the water by reason of certain substances which
it contains is liable, by combining with the tannin, to prevent delay, or prejudice,
the tanning.
It produces a useful commercial result greatly superior to that which is obtained
by the processes heretofore employed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. Tanning hides and skins by means of undiluted liquid tannic extract
substantially as herein before described.
2. The process consisting in first preparing hides or skins as hereinbefore set
forth and afterwards subjecting them to the action of liquid tannic extract
employed without water, or diluting liquid, the said tannic extract being gradually
introduced into the vessel containing the hides or skins in quantities increasing
from the commencement of the operation until the rapidity of the tanning process
decreases and then diminishing the supply as the operation approaches completion
substantially as hereinbefore described.
Dated the 30th day of May 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, Agents.