IMPROVEMENTS IN TANNING, AND IN APPARATUS EMPLOYED FOR THAT PURPOSE
Year: 1881

page_text: LETTERS PATENT to Charles Michel, jr., Charles Kollen, and Gustave Hertzog,
all of Reims, in the Republic of France, for an Invention of "IMPROVEMENTS
IN TANNING, AND IN APPARATUS EMPLOYED FOR THAT PURPOSE."
PROVISIONAL SPECIFICATION left by the said Charles Michel, jr., Charles
Kollen, and Gustave Hertzog at the Office of the Commissioners of Patents
on the 12th April 1881.
CHARLES MICHEL, jr., CHARLES Kollen, and Gustave HERTZOG, all of Reims,
in the Republic of France. "IMPROVEMENTS IN TANNING, AND IN APPARATUS
EMPLOYED FOR THAT PURPOSE."
All the improvements in the methods and apparatus heretofore employed. in
tanning have not enabled the problem of rapid tanning to be solved, it being still
necessary to subject the hides for months to this process.
Some special apparatus for accelerating the process have from time to time been
patented, but they have not been practically successful, either because the processes
were too expensive, or because the tanned hides had not the desired qualities.
The apparatus to which the present Invention relates obviates these difficulties by
permitting calf skins to be tanned in a few hours, and cow or ox hides in about
forty-eight hours, while at the same time affording the leather produced all the
flexibility and firmness indispensable to a perfect product.
The essential objects of these apparatus are, first, to regulate at will, during the
operation of tanning, the temperature of the liquors in the operating tank and in
the receptacle containing the hides to be tanned; second, to regulate the density of
the liquors in the said receptacle and also to change their nature as required for
consecutive processes without interrupting the operation of the apparatus; third,
the clarifying of the liquors used in former processes in order to enable them to serve
for future processes, and it is by the combination of these means that according to
the present Invention rapid tanning may be effected.
For these purposes the skins or hides are introduced into a drum revolving on
horizontal trunnions, one of which is hollow to admit of the passage of a suction

page_text: pipe leading from a pump, and a delivery pipe leading from a raised liquor tank,
both of which pipes descend in the drum within a partition thereof so as to draw
the liquor therefrom and discharge it into the same at or near its lowest point.
From the pump a delivery pipe passes up into the said tank, so that by the pump
the liquor can be withdrawn from the drum while. this continues to revolve, and
can be discharged into the tank, it being made to pass through a refrigerating
apparatus on its way, while from the tank the same liquor may either be discharged
back into the drum after having been raised to any desired temperature by means
of a worm heated by steam or hot water, or the liquor may be passed from the
tank through pipes into one or more filters in order to be clarified, the discharged
clarified liquor being collected in other tanks, whence it can be drawn by the said
pump and discharged into the first named tank again. By these means it will be
seen that while the skins or hides are being continuously subjected to the action
of the rotating drum, the liquor may at the same time be continuously made to
circulate from the drum through the pump, refrigerator, and main tank back to the
drum, whereby a constant definite temperature of the liquor may be maintained
during the tanning operation, the action of the refrigerator and of the heating
worm in the tank being regulated to any required degree. Or during such
operation the liquor may be continuously or periodically clarified by causing it to
pass from the main tank to the filters and thence back to the pump as described.
Or again, where the hides have to be subjected consecutively to a series of different
operations requiring different descriptions of liquors or extracts, these may also be
all effected in one and the same drum by withdrawing the liquors therefrom by
the pump at the end of each particular operation and supplying the liquor required
for the next operation from other tanks, which also communicate with the pump
by pipes. The delivery pipe of the pump also has a branch provided with a stop
cock leading to a discharge drain, so that any particular liquor that has been
employed in the drum and that is of no further use can be withdrawn by
the pump and discharged to waste instead of being conveyed into the main tank
again.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Michel, jr., Charles Kollen, and Gustav Hertzog in the Great
Seal Patent Office on the 12th October 1881.
CHARLES MICHEL, jr., CHARLES KOLLEN, and GUSTAVE HERTZOG, all of Reims,
in the Republic of France. "IMPROVEMENTS IN TANNING, AND IN APPARATUS
EMPLOYED FOR THAT PURPOSE."
Our Invention relates to the tanning of hides or skins, and consists in a novel
method of operating with the aid of a new combination of apparatus whereby we
are enabled to tan effectively the thinner hides, such as calf skins, in a few hours,
and the thicker, such as cow or ox hides, in about forty-eight hours, producing
leather having the flexibility and firmness indispensable to a sound and serviceable
product.
We will first describe the apparatus which we employ, referring to the
accompanying Drawings. Fig. 1 is a longitudinal section partly in elevation, and
Fig. 2 is a plan. A is a wooden drum mounted to revolve on a horizontal axis,
having at each side trunnions that work in suitable bearings. On the one trunnion
is fixed a worm wheel A' gearing with a worm driven by any suitable motor
causing the drum A to revolve slowly, that is to say, to make from 10 to 15
revolutions per minute according to the nature of the hides operated on. The other
trunnion is tubular, and through it pass freely two pipes a and b, which are
supported by an external bracket. The one pipe a bends downwards within the
drum nearly to its inner periphery. A partition p having perforations through it
separates the body of the drum from the end space which the pipes a and b enter.
A manhole D which can be tightly closed by a cover serves to admit into the drum
the hides to be operated on and to remove them. The drum has inwardly projecting
ribs or studs A² which assist in agitating the hides as the drum revolves.
B is a
pump having its suction communicating with the pipe a, and its discharge
communicating by a pipe d with the top of a service tank E. In the course
of the pipe & there is interposed a refrigerator F consisting of a sheaf of
tubes within a casing supplied with cold water or brine that is cooled by a
refrigerating apparatus which is caused to circulate through it while the
liquid conducted by the pipe & flows through the tubes. The service tank E
is placed at a high level on a platform supported by columns, so that there is free
space under it. The top of the tank has an opening, in which is suspended a
wicker basket E', which serves to retain solid matters discharged along with the
liquid from the pipe d. At the bottom of the tank E is placed a serpentine pipe k,
through which steam or hot water can be passed when required to heat the contents
of the tank. From the bottom of the tank the pipe b, provided with a stopcock,
leads to the interior of the drum A. At the side of the tank is placed a
thermometer H to indicate the temperature of the liquid in the tank. I, I, are
filters, having within them perforated removeable trays made of copper, on which
are placed filtering materials, such as small pebbles o, or a mixture of charcoal and
Spanish white p¹, to purify and clarify liquid conducted from the tank E to the
filters by a pipe having stopcocks m, m. The filtered liquid is received in tanks
J, J, from which it is pumped back by the pump B communicating with the tanks
by a pipe n. Other tanks K and L are provided to contain a reserve of liquid and
to allow of subsidence, these reserve tanks being connected by supply pipes with
the service tank E, and having branch pipes r connected to the suction pipe n of
the pump B. The branch pipes to and from the several tanks are provided with
suitable stopcocks, so that they can be charged or emptied as required. By means
of the apparatus arranged as above described the drum A, while it revolves, can be

page_text: The process is similarly conducted, but extended over a longer period, according
to the thickness of the leather, and with liquor strengthened by addition of about
5 lbs. of dividivi to every 100 lbs. of hides treated, or equivalent addition of other
tanning material. For cowhide, for instance, the duration should be about 48 hours,
the final temperature being allowed to rise to nearly 100° Fahrenheit. At the
end of the tanning operation the drum is almost emptied of liquor, and the hides
are subjected for about 15 or 20 minutes to the beating action of the revolving
drum, after which fresh and very strong tanning liquor is gradually introduced into
tlie drum, which is then kept revolving for about two hours. This has the effect
of rendering the leather firm. The bides when tanned whether for hard or soft
leather when removed from the drum are soaked for several hours in weak liquor
at the temperature of the atmosphere. The liquors discharged from the drum are
filtered and clarified and restored to the required strength for a succeeding
operation.
Having thus described the nature of our Invention, and in what manner the
same is to be performed, we hereby declare that we make no general claim to
tanning hides by agitating them within a revolving drum through which tanning
liquids circulate, but we claim,--
First. The herein described process for tanning hides or skins by subjecting them
to agitation within a revolving drum in presence of tanning liquid, which is made
to circulate through the drum and through external apparatus, as described, so that

page_text: while the tanning proceeds the strength and quantity of the liquid can be main-
tained or varied to suit the different stages of the process, and its temperature can
be regulated and prevented from becoming excessive.
Second. The combination of circulating pump, pipes, vessels, and cooling and
heating appliances with a revolving drum having through its trunnion pipes by
which tanning liquids are caused to pass from and to the said vessels into and out
of the drum, so that while the drum revolves the temperature, strength, and
quantity of the tanning liquid within it can be varied, substantially as herein
described.
In witness whereof, we, the said Charles Michel, jr., and Gustave Hertzog, have
hereunto set our hands and seals, this Thirtieth day of June, in the year
of our Lord One thousand eight hundred and eighty one.
CHARLES MICHEL, JR. (L.S.)
GUSTAVE HERTZOG.
(L.S.).