Improveu гrocess for Fanning fies anu sams.
Year: 1899

page_text: Improveu гrocess for Fanning fies anu sams.
We, JESSE HANDCOCK CURLING, of Trowle, Trowbridge, in the County of Wilts,
Scientific Tanner, and CURLING'S TANNERY, LIMITED, of 53, Parliament Street, in
the County of London, do hereby declare the nature of this invention to be as
follows:
This invention relates to an improved process for tanning hides and skins, and
is designed to enable such tanning to be performed in much less time than here-
tofore, and to allow of a superior quality of leather to be obtained.
According to the invention, and after the usual preparatory treatment, we
subject the hides or skins to a special swelling bath before submitting them to
the tanning operation proper which forms the final stage of our improved process.
We also substitute for the bark baths usually employed, certain baths con-
taining special vegetable extracts which give to the leather superior suppleness
and durability and increase the yield. In addition to this, we mix with such
baths a suitable antiseptic, hereinafter mentioned, to prevent any alteration in
their composition, by fermentation during the tanning process.
We furthermore dispense with the ordinary tan pits, and substitute therefor
special circulating tanks or pits as hereinafter fully described.
In carrying out the invention we first subject the hides or skins to a prelimi-
nary washing, cleansing, and depilatory treatment, this last being effected by
lime substantially in the ordinary way, and the hides are afterwards carefully
washed in circulating water, preferably at a temperature of 18 to 20° C., to remove
any traces of lime as its presence would form carbonate of lime and so deprive
the leather of suppleness and colour, and by interfering with the diffusion of the
tanning material, would reduce the ultimate yield.
The water used for the preliminary treatment, and also in the later stages,
should be as free from iron as possible, and it is well that its analysis should
precede every installation.
The skins are then ready for the soaking or swelling process, and to this end
we proceed as follows:
We employ baths composed of the following extracts, either separately or
combined.
Extract Angelica Sylvestris,
Berberis dumit,
Folium Vaccinium Myrtillus,
Erica vulgaris.
We dilute these extracts and acidify them by agents (such as Broom, Gambier
or Mimosa) that give a uniformly known swelling during the different phases of
the operations, and a beneficent action on the hides.
The combination of the above extracts depends upon the nature and the

page_text: different kind of hides to be treated to which they are to be applied, and also to
the climate in which the tanning is to be effected.
Finally, we use mechanical agitation in the baths which facilitates the pene-
tration.
The hides or skins are then placed in our circulating tanks in which the tan-
ning proper is effected, and into which the tanning liquor is introduced and
mixed with a suitable agent, as for instance Berberis dumit; to increase its
diffusibility.
We will now proceed to describe our improved tanks or pits for use in the
swelling and tanning stages, and for this purpose reference is to be made to the
accompanying drawing which shows such a tank in longitudinal section:
a is the tank, b are the hides of which several are suspended separately therein
side by side freely and without tension, c is a vertical partition arranged to one
side of said tank so that the water or liquor can flow freely past its upper and
lower edges d is a perforated false bottom extending horizontally from the lower
edge of the partition c, and e is a pump which is driven in any suitable manner,
for instance by a crank-disc f, and serves to keep the water or
liquor in circula-
tion, say in the direction of the arrows, and thus ensures uniformity in the com-
position of the liquor when such is being used, and a very satisfactory action
on the hides. g is a grid for preventing grit or extraneous matters from choking
the pump.
By means of the above described apparatus, the mechanical agitation constantly
changes the contact of the liquors with the hides and shortens the absorption.
The space left between the hides allows the direct contact of the liquors and
their free circulation. The pressure of the liquid which is directed against the
hides facilitates the penetration.
By our process we are enabled to avoid the defects now inherent in tanning
in pits, and which are:
1. Constant exhaustion of the liquor at the end of the laying away in the pits
where the leather becomes flat and distends itself.
2. The use of barks does not allow the utilization of products that are favour-
able to the leather. Hence the primordial principle: suppression of the putting
in pits, use of the extracts which, to the exclusion of the barks, contain extractive
matters which give the leather suppleness, durability, and a superior yield.
As regards the use of an antiseptic before referred to, we prefer to employ
folium Vaccinium Myrtillus, as besides its antiseptic properties it is in itself a
tanning agent, as was mentioned previously in connection with the swelling baths.
In the ordinary process of tanning, the fermentation which takes place in the
juices, and to which no beneficent action is yet assigned, is very injurious; it
disaggregates the hide which loses its weight and quality, the tannin decomposes
itself into gallic and lactic acids and into glucose, which products cannot be bene-
ficial to the hides, hence our addition of an antifermentiscible agent, that will
be favourable to the hides by preventing alteration of the juices, is extremely
important.
Furthermore, by means of our improved process, we can tan heavy hides in say
24 hours, and light skins in as little as 40 minutes.
As regards the use of acids, we discard the same altogether except what is
necessary in the action of "bateing." This we do for the following considera-
tions:
1. When the hides have undergone the action of liquors the acidity of which
increases with the amount of tannin, a soft spongy leather results.
2. When the acidity stops too short, the penetration of the tannin is imperfect,
the leather being hard and brittle. The method of bateing commonly in use in
tanneries is exposed to both these defects. The composition of the liquors we use
relies on this principle: descending progress in the acidity and ascending in the
proportions of the tanning liquors.
The final result obtained depends upon :-(1) the proportion of the tanning

page_text: matter fixed on the hide, or, in other words, in the same conditions of tempera-
ture and of acidity, and in an equally diluted solution of tannin, the same hide
always absorbs the same quantity of tannin; (2) the species of the tannin and its
relation with the extractive matters alter the quality and the yield of the hides.
Hence it is a principle of our process always to work under the same conditions
and to adopt a judicious selection of the extracts to obtain an invariable quality
and yield.
Improved Process for Tanning Hides and Skins.
We, JESSE HANDCOCK CURLING, of Trowle, Trowbridge, in the County of Wilts,
Scientific Tanner, and CURLING'S TANNERY, LIMITED, of 53, Parliament Street, in
the County of London, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, that is to say:-
This invention relates to an improved process for tanning hides and skins, and
is designed to enable such tanning to be performed in much less time than here-
tofore, and to allow of a superior quality of leather to be obtained.
According to this invention and after the usual preparatory treatment, we
subject the hides or skins to a special swelling bath before submitting them to
the tanning operation proper which forms the final stage of our improved process.
We also substitute for the bark baths usually employed, certain baths con-
taining special vegetable extracts which give to the leather superior suppleness
and durability and increase the yield. In addition to this, we mix with such
baths a suitable antiseptic, hereinafter mentioned, to prevent any alteration in
their composition by fermentation during the tanning process.
In carrying out our invention we first subject the hides or skins to a prelimi-
nary washing, cleansing, and depilatory treatment, this last being effected by lime
substantially in the ordinary way, and the hides are afterwards carefully washed
in circulating water, preferably at a temperature of 18° to 20° C., to remove any
traces of lime, as its presence would form carbonate of lime and so deprive the
leather of suppleness and colour, and by interfering with the diffusion of the
tanning material would reduce the ultimate yield.
The water used for the preliminary treatment, and also in the later stages,
should be as free from iron as possible, and it is as well that its analysis should
precede every installation.
The skins are then ready for the soaking or swelling process, and to this end
we proceed as follows:
We employ baths composed of the following extracts, either separately or
combined.
Extractum Angelica Sylvestris (Angelica tree).
Berberis dumus (Common Barberry).
Folium Vaccinium Myrtillis (Extract of myrtle leaves).
Erica vulgaris (Common heath).
These may be employed in equal proportions and mixed with about 20 times
their volume of water.

page_text: We dilute these extracts and acidify them by agents such as Broom, Gambier,
or Mimosa, that give a uniform known swelling during the different phases of
the operations and a beneficient action on the hides.
The combination however of the above extracts depends upon the nature and
the different kinds of hides to be treated to which they are to be applied, and
also to the climate in which the tanning is to be effected.
Finally, we use mechanical agitation in the baths, which facilitates the pene-
tration.
The hides or skins are now placed in circulating tanks in which the tanning
proper is effected, and into which the tanning liquor is introduced and mixed
with a suitable agent, as for instance 2 per cent. of Berberis dumus to increase
its diffusibility.
As regards the use of an antiseptic before referred to, we prefer to employ
folium vaccinium myrtillus, as, besides its antiseptic properties, it is in itself a
tanning agent.
In the ordinary process of tanning, the fermentation which takes place in the
juices, and to which no beneficient action is yet assigned, is very injurious; it
disaggregates the hide which loses its weight and quality, the tannin decomposes
itself into gallic and lactic acids and into glucose, which products cannot be
beneficial to the hides, hence our addition of an antifermentiscible agent, that
will be favourable to the hides by preventing alteration of the juices, is extremely
important.
We will now describe a suitable tank or pit for use in the swelling and tanning
stages, and for this purpose reference will be made to the drawing accompanying
our Provisional Specification which shews such a tank in longitudinal section.
It should be understood however that we make no claim to this construction of
tank.
a is the tank, b are the hides of which several are suspended separately therein
side by side freely and without tension, c is a vertical partition arranged to one
side of said tank so that the water or liquor can flow freely past its upper and
lower edges, d is a perforated false bottom extending horizontally from the lower
edge of the partition c, and e is a pump which is driven in any suitable manner,
for instance by a crank-disc f, and serves to keep the water or liquor in circula-
tion, say in the direction of the arrows, and thus ensures uniformity in the com-
position of the liquor when such is being used, and a very satisfactory action
on the hides. g is a grid for preventing grit or extraneous matters from choking
the pump.
By means of such an apparatus the mechanical agitation constantly changes
the contact of the liquors with the hides and shortens the absorption. The space
left between the hides allows the direct contact of the liquors and their free cir-
culation. The pressure of the liquid which is directed against the hides facilitates
the penetration.
By our process we are enabled to avoid the defects now inherent in tanning
in ordinary pits, and which are:-
1. Constant exhaustion of the liquor at the end of the laying away in the pits
where the leather becomes flat and distends itself.
2. The use of barks does not allow the utilization of products that are favour-
able to the leather.
Hence the fundamental principles on which this invention is based are:-
The suppression of the putting in the ordinary pits, and the use of the extracts
which, to the exclusion of the barks, contain extractive matters which give the
leather suppleness, durability, and a superior yield.
By means of our improved process, we can tan heavy hides in say 24 hours,
and light skins in as little as 40 minutes.
As regards the use of acids, we discard the same altogether except what is
necessary in the action of "bating." This we do for the following considera-
tions:-

page_text: 1. When the hides have undergone the action of liquors, the acidity of which
increases with the amount of tannin, a soft spongy leather results.
2. When the acidity stops too short, the penetration of the tannin,
the leather being hard and brittle.
imperfect,
The method of bating commonly in use in tanneries is exposed to both these
defects.
The composition of the liquors we use relies on this principle: descending pro-
gress in the acidity, and ascending in the proportions of the tanning liquors.
The final result obtained depends upon : (1) the proportion of the tanning
matter fixed on the hide, bearing in mind that under the same conditions of
temperature and of acidity, and with an equally diluted solution of tannin, the
same hide always absorbs the same quantity of tannin; (2) the species of the
tannin and its relation with the extractive matters alter the quality and the yield
of the hides.
Hence it is a principle of our process always to work under the same conditions
and to adopt a judicious selection of the extracts to obtain an invariable quality
and yield.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. The process of tanning hides and skins which consists in depilating them,
swelling them in an anti-septic liquor and then treating them with a tanning
liquor rendered anti-septic and containing extract of Berberis dumus, substan-
tially as described.
2. For use in the process covered by the preceding claim, the employment,
as the anti-septic liquor, of a swelling bath containing any of the four extracts
mentioned, or containing them all in equal proportions, substantially as described.
3. Our improved process for tanning hides and skins substantially as described.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, E.C., and 5A Market Street, Nottingham,
Agent for the Applicants.