LMPROVEMENTS IN TANNING, AND IN APPARATUS CONNECTED THEREWITH
Year: 1876

page_text: LETTERS PATENT to Bristow Hunt, of Serle Street, Lincoln's Inn, in the
County of Middlesex, Gentleman, for the Invention of "LMPROVEMENTS IN
TANNING, AND IN APPARATUS CONNECTED THEREWITH.” A communication
from abroad by Philippo Joseph Dussaud, Jean Dussaud, Joseph Duchez, and
Jacques Bendinger, of Bordeaux, France.
Sealed the 30th Juno 1876, and dated the 2nd May 1876.
PROVISIONAL SPECIFICATION left by the said Bristow Hunt at the Office
of the Commissioners of Patents on the 2nd May 1876.
BRISTOW HUNT, of Serlo Street, Lincoln's Inn, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN TANNING, AND IN APPARATUS CONNECTED THERE-
WITH." (A communication from abroad by Philippe Joseph Dussaud, Jean
Dussaud, Joseph Duchez, and Jacques Bendinger, of Bordeaux, France.)
The object of this Invention is to abridge considerably the time occupied in the
tanning of hides and skins, as effected by the ordinary process of maceration in
pits by forcing the tanning material to penetrate through the entire thickness of
the hides in a rapid and complete manner.
This new method of tanning comprises a scries of operations which will now be
described in their order.
First Operation. The hides having been unhaired and washed are placed in vats
containing a weak tanning liquor; they are frequently agitated, and they remain
therein from 12 to 72 hours, according to their thickness and quality, care being
taken to increase the strength of the liquor every 24 hours for thick skins.
Second Operation. The hides being withdrawn from the vats are placed in a
closed vessel of suitable form capable of supporting a pressure of eight kilogrammes,
and rendered unattackable by tannic acid. They are arranged as in an ordinary
vat, that is to say, in layers, interposing between them an inactive material.
Spent bark which is deprived of its tannin answers this purpose best. The vat is
then filled with tanning liquor stronger than that used in the first operation.
Pressure is then applied, and the hides or skins are left under pressure from two to
five days, according to their quality.
Third Operation. After this delay the vessel is entirely emptied and cleansed,
the liquor, the inactive material, and the hides being withdrawn. The hides are
then placed back again into the vat, arranged as before, replacing the inactive
[Price 6d1

page_text: .
material by bark or tanning matter containing all its tannin. The vessel is filled
with the liquor used in the second operation, or with liquor of the same strength.
It is then again put under pressure at once for very thin hides, and at the end of
four days for thicker ones in cases where the tanning matter is liquid. In order
that the hides may remain always isolated from each other care must be taken at
the commencement of this third operation only to remove the liquor without
disturbing the hides or the matter which isolates them. According to the thick-
ness and quality of the hides remaining under pressure for from two to five days
will suffice for tanning thin hides or skins.
Fourth Operation. For hides of medium thickness, after remaining fifteen days
under pressure in the third operation, they should be removed from the vessel, and
the bark or tanning matter which has parted with its tannin should be replaced
with fresh material containing all its tannin, the hides being always arranged as
before. The vessel is filled with the liquor of the preceding operation or with
liquor of the same strength, and at the expiration of from four to six days,
according to the thickness and quality of the hides, the pressure is applied.
From 15 to 20 days under pressure suffices for the entire tanning of this class
of hides.
Fifth Operation.-For hides of great thickness, at the expiration of 20 days
under pressure in the fourth operation they should be removed from the vessel, and
the bark or tanning matter which has parted with its tannin, with fresh material
containing all its tannin, the hides being arranged always in layers, as before.
The vessel is filled with the liquor of the fourth operation, or with liquor of the
same strength and pressure is applied at the end of 12 days. 25 days under
pressure is sufficient to complete the tanning.
The pressure should be a few kilogrammes only in the second operation, and
should be gradually increased at each operation, until finally it reaches about
8 kilogrammes.
In cold weather, for tanning in the time above-named, it is necessary that the
place containing the closed vessel should be kept at a temperature not less than 10
degrees above zero (centigrade).
The series of operations above described may be carried on in a closed vessel of
any form, but the vessel or apparatus herein-after described has given good results,
although the Inventors do not wish to confine themselves exclusively to its use.
This vessel or apparatus is composed of a large cylinder closed at its two ends
by spherical caps. At the upper part is an opening for charging the same firmly
closed by a cover. Towards the lower part is fitted a screen on false bottom
intended to support the hides. This false bottom is in three pieces, and covered
with metallic wire cloth so that it can be easily raised and replaced.
Along the vertical walls of the cylinder are arranged metallic tubes pierced all
over with holes, and intended to facilitate the distribution of the liquor in the
apparatus, and its flowing away during the emptying.
The false bottom being put in its place, the workman who is in the cylinder
spreads out a layer of material, either inactive or having all its tannin, according to
the operation which he is carrying on; then he spreads the hides and arranges
them in horizontal layers, separating them from each other by the said material, as
above described. The tanning liquor is then admitted by a tube into the apparatus,
and when the latter is filled pressure is given by means of another tube, a tap
allowing the air to escape during the filling. A manometer indicates the pressure
at any period of the operation, and a weighted safety valve prevents the pressure
from exceeding a certain limit. At the lower part a tube terminated by a rose and
provided with a suitable tap allows the tanning liquor to be drawn off from the
vessel into a tube outside the apparatus.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Bristow Hunt in the Great Seal Patent Office on the 30th June
1876.
BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the County of Middlesex,
5 Gentleman. "IMPROVEMENTS IN TANNING, AND IN APPARATUS CONNECTED THERE-
WITH." A communication to me from abroad by Philippe Joseph Dussaud, Jean
Dussaud, Joseph Duchez, and Jacques Bendinger, of Bordeaux, France.
The object of this Invention is to abridge considerably the time occupied in the
tanning of hides and skins as effected by the ordinary process of maceration in pits
by forcing the tanning material to penetrate through the entire thickness of the
hides in a rapid and complete manner.
This new method of tanning comprises a series of operations which will be
described in their order.
First Operation.-The hides having been unhaired and washed are placed in vats
containing a weak tanning liquor. They are frequently agitated, and they remain
therein from 12 to 72 hours, according to their thickness and quality, care being
taken to increase the strength of the liquor every 24 hours for thick skins.
Second Operation.-The hides being withdrawn from the vats are placed in a
closed vessel of suitable form capable of supporting a pressure of 8 kilogrammes,
and rendered unattackable by tannic acid. They are arranged as in an ordinary
vat, that is to say, in layers, interposing between them an inactive material.
Spent bark which is deprived of its tannin answers this purpose best. The vat is
then filled with tanning liquor stronger than that used in the first operation.
Pressure is then applied, and the hides or skins are left under pressure from two to
five days, according to their quality.
Third Operation. After this delay the vessel is entirely emptied and cleansed,
the liquor, tho inactive material, and the hides being withdrawn. The hides are
then placed back again into the vat, arranged as before, replacing the inactive
material by bark or tanning matter containing all its tannin. The vessel is filled
with the liquor used in the second operation, or with liquor of the same strength.
It is then again put under pressure at once for very thin hides, and at the end of
four days for thicker ones in cases where the tanning matter is liquid. In order
that the hides may remain always isolated from each other care must be taken at
the commencement of this third operation only to remove the liquor without
disturbing the hides or the matter which isolates them. According to tho thickness
and quality of the hides remaining under pressure for from two to five days will
suffice for tanning thin hides or skins.
Fourth Operation.-For hides of medium thickness, after remaining fifteen days
under pressure in the third operation they should be removed from the vessel, and
the bark or tanning matter which has parted with its tannin should be replaced
with fresh material containing all its tannin, the hides being always arranged as
before. The vessel is filled with the liquor of the preceding operation or with
liquor of the same strength, and at the expiration of from four to six days,
according to the thickness and quality of the hides, the pressure is applied.
From 15 to 20 days under pressure suffices for the entire tanning of this class
of hides
Fifth Operation-For hides of great thickness, at the expiration of 20 days
under pressure in the fourth operation, they should be removed from the vessel,
and the bark or tanning matter which has parted with its tannin should be
replaced with fresh material containing all its tannin, the hides being arranged
always in layers, as before. The vessel is filled with the liquor of the fourth
operation, or with liquor of the same strength and pressure is applied at the end
of 12 days. 25 days under pressure is sufficient to complete the tanning.
The pressure should be a few kilogrammes only in the second operation, and

page_text: should be gradually increased at each operation, until finally it reaches about
8 kilogramines.
In cold weather, for tanning in the time above-named, it is necessary that the
place containing the closed vessel should be kept at a temperature not less than 10
degrees above zero (centigrade).
The series of operations above described may be carried on in a closed vessel of
any form, but the vessel or apparatus herein-after described has given good results,
although the Inventors do not wish to confine themselves exclusively to its use.
The accompanying Drawings show clearly the construction and operation
thereof.
Figure 1 is an external elevation of the apparatus, and Figure 2 is a corre-
spending plan view. Figure 3 is a vertical section through the line 1-2, and
Figure 4 is a horizontal section through the line 3-4.
This vessel or apparatus is composed of a large cylinder closed at its two ends
by spherical caps. At the upper part is an opening for charging the same. Firmly
closed by a cover towards the lower part is fitted a screen or false bottom S
intended to support the hides. This false bottom is in three pieces, and covered
with metallic wire cloth so that it can be easily raised and replaced.
Along the vertical walls of the cylinder are arranged metallic tubes R pierced all
over with holes, and intended to facilitate the distribution of the liquor in the
apparatus, and its flowing away during the emptying.
The false bottom being put in its place the workman who is in the cylinder
spreads out a layer of material T, either inactive or having all its tannin, according
to the operation which he is carrying on; then he spreads the hides and arranges
them in horizontal layers, separating them from each other by the said material T,
as above described. The tanning liquor is then admitted by the tube I into the
apparatus, and when the latter is filled pressure is given by means of the tube J, n
tap H allowing the air to escapo during the filling. A manometer G indicates the
pressure at any period of the operation and a weighted safety valve P prevents the
pressure from exceeding a certain limit. At the lower part a tube terminated by a
rose V and provided with a tap L allows the tanning liquor to be drawn off from
the vessel into a tubo M outside the apparatus.
Having thus particularly described the said Invention, and the manner in which
the same is to be or may be performed, I have to state in conclusion that what I
claim as the Invention communicated to me by the said Philippe Joseph Dussaud,
Jean Dussaud, Joseph Duchez, and Jacques Bendinger, is, the mode of tanning in a
closed vessel under pressure, as above described, together with the various operations
comprised, and also the apparatus employed to attain this result without limitation
to any special form, but reserving the right to employ closed vessels of any shape
capable of applying the principles on which this Invention is based.
In witness whereof, I, the said Bristow Hunt, have hereunto set my hand
and seal, this Thirtieth day of June, in the year of our Lord One thousand
eicht hundred and seventy-six.
BRISTOW HUNT. (L.S.)