IMPROVEMENTS IN »> TANNING HIDES, AND IN APPARATUS THEREFOR A
Year: 1882

page_text: LETTERS PATENT to Arthur Charles Henderson of 6 Southampton Buildings
.
.
Holborn in the county of Middlesex for an invention of IMPROVEMENTS IN
»>
TANNING HIDES, AND IN APPARATUS THEREFOR A communication from
abroad by the firm of Casimir Bez and Sons, Tanners of Léran in the Republic
of France
PROVISIONAL SPECIFICATION left by the said Arthur Charles Henderson
at the Office of the Commissioners of Patents on the 27th March 1882.
ARTHUR CHARLES HENDERSON of 6 Southampton Buildings Holborn in the
county of Middlesex "IMPROVEMENTS IN TANNING HIDES, AND IN APPARATUS
THEREFOR A communication from abroad by the Firm of Casimir Bez and Sons
Tanners of Léran in the Republic of France
"
This invention relates to the tanning of hides by aid of a continuous flow or
current of tannic liquor. The method is as follows: the raw hides are suspended
vertically on poles arranged horizontally, and resting across the tanning vats or
pits, these pits are on a gentle incline to encourage the flow of the liquid, and
this latter is made and is contained in vats at a lower level than the tan pits.
The tanning substances are deposited on a grating above the bottom of the pit
in which the tannic liquid is made, so that this pit (or pits as the case may be)
has a double bottom; in the lowest portion is a suction and force pump for raising
the tanning liquor (made in this pit by admitting water above the tanning matters)
to a reservoir above this pit, and a little above the tanning pits, which are a
succession of vats arranged in pairs. This reservoir is provided with a grating
near the top to prevent the passage of solid matters held in suspension, and being
filled as described the liquid overflows through an aperture at the top of the first
pair of pits, and fills the next pair passing through an aperture. at the bottom of
these pits, it again fills the next pair, and passes through an aperture at the top,
and so on passing through openings alternately top and bottom, till it reaches the
last pit; in this latter a pipe cnters, and by a gentle slope leads the liquid back

page_text: again to its source of origin, namely the vat in which it is made, to go through
the same course again, so establishing a constant flow of liquid of uniform
strength.
The skins being arranged vertically in each tanning pit on the poles running
longitudinally so that the tanning liquor thoroughly washes the skins on all sides
in its passage and so impregnates them with the tannic matter.
The reservoir containing the prepared liquid is provided with an internal agitator
to prevent any deposit that might arise from being in a state of rest.
When a double set of tan pits, and two pits for composition of the tannic liquor
are employed the same arrangement is adhered to and then a double branched
pipe leads the liquor from each of the last rows of vats back to their respective
liquor manufacturing vats.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Arthur Charles Henderson in the Great Seal Patent Office on the
23rd September 1882.
ARTHUR CHARLES HENDERSON of 6 Southampton Buildings Holborn in the
County of Middlesex IMPROVEMENTS IN TANNING HIDES AND IN APPARATUS
THEREFOR A communication from abroad by the firm of Casimir Bez and Sons,
Tanners of Leran in the Republic of France
Many systems and processes for tanning have been employed for replacing pit
tanning which up to the present time has been the most successful, both in an
industrial and economical point of view. For some years past it has been the
custom to place the hides in the pits not only horizontally, alternated by vegetable
astringent matters, but also vertically, suspended across poles, so that the skins
hang in a tanning liquid; but this arrangement whilst submitting all parts of the
skin to the immediate action of the tannin, has nevertheless failed to produce the
results expected. The inventors attribute this to the decomposition of the tannic
liquor from remaining stagnant, the essential parts of the liquor precipitating, so
that in a short time the skins are found in a mere neutral mass.
The inventors however have conceived (which is the characteristic feature of
their invention) the idea of submitting the skins whilst suspended in the pits in a
position parallel one with the other to the action of a tanning liquid, which con-
tinually forms a double current across the skins and passes naturally from one pit
to another, reaching the upper part of one to penetrate to the bottom of the next
pit, and so on in succession, so that the constituent elements of this tanning liquid
are constantly stirred or agitated so as to form a homogeneous whole, diminishing
only in its action as it becomes more distant from its source of production.
In the accompanying drawings Fig 1 is a section following the longitudinal axis
of the pits as arranged and as embodying this invention. Fig 2 is a plan of
the same showing a twin or double arrangement. Fig 3 is a detail on a larger
scale.
The tannic liquor is made in the pits a. a. at the head of the construction and
below the tanning pits, the reason of which will be hereafter explained.
The pits a. a have double bottoms perforated with holes b, on which the
vegetable astringent substances are placed. The water passing through these
substances becomes impregnated with the tannin and passes under the bottom b,
having acquired all the requisite qualities. A suction and force pump c, whose
suction tube c¹ debouches between the bottoms of the pits, transfers the tannic
liquid to the lower part of the juice or liquid pit d; the top level of which comes
above a grating d', intended to stop the solid matters held in suspension in the
liquid. This liquor pit is furnished with an agitator gifted with two movements
an up and down penetrating motion and a simultaneous rotary one.
In this manner the liquor which would become hard from rest, is attacked not
through the whole mass which would require considerable force, but progressively
as fast as the agitator descends.
Following the line with the pit d, are a succession of pits more or less in number
and dimensions f. f. f. f¹ all alike, and two and two, all having a fixed incline, to
produce a natural flow of the liquid at a gentle speed regulated as experience may
prove requisite.
The pits f, f, have their sides pierced at the top with holes g, through which the
liquid from the pit d reaches the first pit, and the liquor from the pit f³, enters
the second and so on in succession till the last is reached. The pits f' whose sides

page_text: are pierced below with holes h, consequently receive the liquor of the pits f (which
precede them) at the bottom, and the same pits f receive it at the top, the result
being that the liquor from the reservoirs d, has a double flow of transfer from pit
to pit, and of ascent, and descent in leaving the level of one to reach the bottom of
the next successively until the last is reached, in this a pipe is placed reaching
to the level of the liquid, and being gently sloped the weakened liquid is returned
to its source of origin, viz: the pit a. and being renewed and strengthened, it is
thence forced by the pump to form a continuous current.
In the pits f, f¹, ff, the skins to be tanned are suspended on wooden poles m,
.resting across the partitions of the pits, all the poles being arranged parallel with
the direction of the flow of the liquid, the skins consequently receive the action of
the tannic liquor all over them, which however becomes weaker as the pits are
furthest separated from the source of origin of the liquor which is then returned
as described to acquire renewed strength.
As the strongest liquors are the most dense, deposits are left at the bottoms
of the pits which are occasioned by the liquid resting all night; no ill effects
however result from this the skins being hung in the pits with the thickest parts
downwards.
Where double sets of pits are used, the liquor is returned to the manufacturing
pit a by a bifurcating pipe k.
The inventors claim as their invention the exclusive right to the above described
method of tanning skins or hides, which consists in hanging the skins vertically
in the pits on poles placed horizontally across the pits, and in submitting them to
the action of a continuous current of tannic liquor, which flows from one pit to
the other in a double current, the first being a natural and continuous course from
pit to pit, and the second from top to bottom of the pits, and vice versa, to the
last one whence the liquor is returned to the manufacturing pit, to be strengthened
and again flow on in the same manner through the several pits.
After the skins have remained long enough they are removed from the first pit
and replaced by those from the second, and then by the third, and so on till the
last skins are reached, these are then put into the first pit, and fresh skins placed
where the last were removed from; by this arrangement the skins throughout the
pits that had received, the action of the tannic liquor from the top to the bottom,
then receive it from bottom to top.
In witness whereof I the said Arthur Charles Henderson have hereunto set
my hand and seal this twenty second day of September in the Year of Our
Lord One thousand eight hundred and eighty two.