A New Process for Tanning and Apparatus relating thereto.
Year: 1891

page_text: Date of Application, 12th Dec., 1891
Complete Specification Left, 12th Sept., 1892-Accepted, 15th Oct., 1892
PROVISIONAL SPECIFICATION.
A New Process for Tanning and Apparatus relating thereto.
We GUSTAVE VAN HAECHT, Engineer and CHARLES OBOZINSKI, Engineer
both of 52 Rue de Billard, Brussels in the Kingdom of Belgium do hereby declare
the nature of this invention to be as follows:-
Our invention has for itsobject the production of leather in a rapid manner, at
the same time preserving all those properties which are now produced by the best
known process.
It consists in the alternate and convenient applications of the actions both of
vacuum and pressure; and in the arrangement and combination of hides with
special materials interposed between them; and also in a new apparatus designed
for the purpose of carrying out our process.
The stretched skins to be tanned are disposed in a particular manner hereinafter
described, in a closed vessel or vat of suitable shape and sufficiently strong to resist
the forces of vacuum and of pressure; the vacuum has for its object to extract the
air contained in the skins and in the vessel in order that the solutions introduced
into the apparatus shall act completely, rapidly, and uniformly between the
different thicknesses of the skins; and the pressure, after the liquor has been
introduced, will increase and complete the said effect produced by the vacuum.
We place two pumps in communication with the said vessel one to produce the
vacuum, the other to exert the pressure; and in general we procced in the
following manner :-
In the vessel in which the skins are placed we dispose a perforated casing the
lower part of which forms a false bottom to facilitate einptying, and the extraction
of the air contained in the skins.
On the false bottom we place-
1st. A layer of wood-wool (thin shavings and long fibres) previously impregnated
with tannin.
2nd. On this layer of wood-wool a sheet of wool or other fabric also impregnated
with tannin.
3rd. On this sheet a skin to be tanned.
4th. On the skin another sheet.
5th. On this sheet another layer of wood-wool, and so on until the vat is
completely filled.
This new combination has for its objects :-
First with regard to the use under these conditions of wood-wool: to completely
separate the skins, this being important since wood-wool is a very soft inexpensive
material containing as few as possible projecting and hard particles or bodies
which might adhere to the skins, and so prevent the tannin from acting in such
parts of the skin.
:
Secondly with regard to the employment of the textile fabric to complete the
action of the wood-wool. If the wood-wool were to be used alone in direct contact
with the skin it might still leave some hard particles in contact therewith which would
protect the skin from the action of the tannin at these points; further the unequal
interstices which naturally exist amongst the fibres of the wood-wool would be liable
to cause unequal quantities of liquor to act upon the skin at different places—an ill
effect which is prevented by the interposition of the textile fabric as the suppleness
and porosity of the latter enables it to equalize the amount of tannin acting upon the
skins.
When the vat is full we produce the vacuum in it by extracting the ‘air

page_text: contained in the apparatus and in the skins, thus efficiently opening the pores of the
skins.
Next we allow the liquor to run into the vat until it is full and then we apply
the pressure apparatus.
When the required pressure is attained in the vat we leave it to operate thus on
all the interior points and on all the contents of the vat during a period of time
which will vary according to the nature of the skins to be tanned.
We then open a connection adapted to effect the complete emptying of the vessel,
and we may force back the liquor into a reservoir from whence it may be returned
into the first vessel for re-usc.
30
Obviously we do not confine ourselves to the precise particulars or details of the
process indicated as we may directly introduce the liquor under pressure by known
mechanical means, and also we may change the order or disposition of layers of
shavings and textile fabrics among the skins.
After a certain time we recommence the operation or operations by augmenting
in some degree the strength of the tannin, and increasing by pressure the penetration
of the liquid until the tanning is completed under the required conditions.
Dated this 19th day of December 1801
J. C. CHAPMAN,
Agent.
COMPLETE SPECIFICATION.
A New Process for Tanning and Apparatus relating thereto.
We, GUSTAVE VAN HAECHT, Engineer, and CHARLES OBOZINSKI, Engineer,
both of 52, Rue de Billard, Brussels, in the Kingdom of Belgium, 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 :-
Our invention has for its object the production of leather in a rapid manner, at
the same time preserving all those properties which are now produced by the best
known processes.
It consists in the alternate and convenient applications of the actions both of
vacuum and pressure, and in the arrangement and combination of hides with special
materials interposed between them, and also in a new apparatus designed for
carrying out our process.
The stretched skins to be tanned are disposed in a particular manner hereinafter
described, in a closed vessel or vat of suitable shape and sufficiently strong to
resist the forces of vacuum and of pressure; the vacuum has for its object to extract
the air contained in the skins and in the vessel in order that the solutions introduced
into the apparatus shall act completely, rapidly and uniformly between the different
thicknesses of the skins; and the pressure, after the liquor has been introduced, will
increase and complete the said effect produced by the vacuum.
We place two pumps in communication with the said vessel, one to produce the
vacuum, the other to exert the pressure; and in general, we proceed in the following
manner :-
In the vessel in which the skins are placed, we dispose a perforated casing, the
lower part of which forms a false bottom, to facilitate emptying and the extraction
of the air contained in the skins.
On the false bottom we place
1st. A layer of wood-wool (thin shavings and long fibres) previously impregnated
with tannin.
2nd. On this layer of wood-wool, a sheet of wool or other fabric, also impregnated
with tannin.
3rd. On this sheet a skin to be tanned.
4th. On the skin another sheet.

page_text: 5th. On this sheet another layer of wood-wool, and so on until the vat is
completely filled.
This new combination has for its objects :-
First, with regard to the use under these conditions of wood-wool: to completely.
separate the skins; this being important since wood-wool is a very soft inexpensive
material containing as few as possible projecting and hard particles or bodies which
might adhere to the skins, and so prevent the tannin from acting on such parts of
the skin.
Secondly with regard to the employment of the textile fabric: to complete the
action of the wood-wool. If the wood-wool were to be used alone in direct contact
with the skin, it might still leave, some hard particles in contact therewith which
would protect the skin from the action of the tannin at these points; further the
unequal interstices which naturally exist amongst the fibres of the wood-wool would
be liable to cause unequal quantities of liquor to act upon the skin at different
places, an ill effect which is prevented by the interposition of the textile fabric, as
the suppleness and porosity of the latter enable it to equalize the amount of tannin
acting upon the skins.
―:
When the vat is full we produce the vacuum in it by extracting the air contained
in the apparatus and in the skins, thus efficiently opening the pores of the
skins.
Next we allow the liquor to run into the vat until it is full and then we apply the
pressure apparatus.
When the required pressure is attained in the vat we leave it to operate thus on
all the interior points and on all the contents of the vat during a period of time
which will vary according to the nature of the skins to be tanned.
We then open a connection adapted to effect the complete emptying of the vessel,
and we force back the liquor into a reservoir from whence it may be returned into
the first vessel for re-use.
Obviously we do not confine ourselves to the precise particulars or details of the
process indicated, as we may directly introduce the liquor under pressure by known
mechanical means, and also we may change the order or disposition of layers of
shavings and textile fabric among the skins.,
After a certain time we recommence the operation or operations by augmenting
in some degree the strength of the tannin and increasing by pressure the penetration
of the liquid until the tanning is completed under the required conditions.
In further description of our new process we have annexed a drawing of an
apparatus designed for performing the same. The figure is a sectional elevation.
A is the vat and J the perforated casing, and false bottom for receiving the skins and
their intermediate layers as above described and which it is not necessary to illustrate.
B'is an airtight cover fixed by clamps as illustrated or in other suitable manner and
having a vacuum gauge b, a handle for raising it, an air cock 2, and a pressure
gauge b
E is a pump connected to A by pipe e with a suitable cock, for the
purpose of producing vacuum in A.; C is a pressure pump. D is the tank
containing the liquid which is forced through pipe d into A, a suitable cock
being provided upon the pipe as shown. F is a high level reservoir of liquor or
water for introduction into A by pipe f, and f' is a stop cock thereon. G is a
reservoir for final discharge through the pipe g and cock.g'. H is a pump for
returning the discharged liquor to the high level reservoir F.
Applying to this special apparatus the process as above set forth :-The
perforated case J being filled with alternate skins and layers of special materials,
as specified, the vat A is hermetically sealed by cover B. Vacuum is then made
by pump E and the contents in A are left under the action of vacuum during the
time necessary for the opening of the pores of the skins and the extraction from
them of all fatty matters.
The liquor having been previously forced from G by pump H into reservoir F,
the cock is opened and the liquor from F instantly fills A to the desired height
which is ascertained on the water gauge X, then the cock is shut and 6* is

page_text: immediately, opened to liberate the air cushion formed between the liquor, and the
cover B. The cock f¹ is then closed and the pressure pump C started which forces
into the vat A a certain quantity of liquor in order to establish a pressure upon all
the interior parts of the apparatus, which pressure will vary according to the
strength of the liquor. Care must be taken to shut the cock 62 as soon as the
liquor comes out, to prevent waste. The pores of the skin having been absolutely
opened previously by the vacuum action, this penetration of tannin under pressure
acts very effectually. The cock on pipe d of pump C is then shut and the contents
of the vat A are left to the action of the liquor under pressure, effected under the
prescribed conditions during a certain time. When this operation is finished, the
emptying cock g₁ and air cock 62 are opened and all the liquid contents of the vat A
are allowed to flow into the discharge reservoir G, from whence they may be
returned by the pump H to the reservoir F for continuation of the operation which
we have above specified.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1st. The hereinbefore described new process of tanning, consisting in placing in
a perforated casing enclosed in a vessel or vat adapted to be made airtight the
skins to be tanned having interposed between each of them a layer of wood-wool,
and of textile fabric, both substances being impregnated with tannin; then creating
a vacuum in said vat and maintaining same for a suitable period of time; then
admitting the tanning solutions, and applying pressure thereto, and allowing a suitable
period of time for action thereof upon the skins, and finally drawing off the liquor
and removing the skins, substantially as and for the purposes set forth.
2nd. In the new process of tanning hereinabove described and claimed, the use
of an apparatus constructed and arranged substantially in the manner shown on the
annexed drawing, whereby also when the process is completed, the same liquor
(with strengthening addition when required) may be re-used for the next operation,
substantially as described and illustrated.
3rd. In the process of tanning, the use of a layer or layers of wood-wool (being
thin shavings of wood with long fibres) combined with a sheet or sheets of wool or
other textile fabric, both impregnated with tannin, and interposed between the
skins for the purposes hereinabove set forth.
Dated this 12th day of September 1892.