Electricity.
Year: 1888

page_text: Date of Application, 17th Jan., 1888
Complete Specification Left, 17th Oct., 1888
Complete Specification Accepted, 16th Mar., 1889
Electricity.
I, LORENTZ ALBERT GROTH, of 3 Tokenhouse Buildings, in the City of London,
Civil Engineer do hereby declare the nature of this invention to be as follows:-
It is well known that if a sufficiently powerful current of electricity be passed through
tanning liquor in which hides or skins are being tanned the process of tanning is
thereby hastened; but, so far as I am aware, all the means heretofore proposed for
applying electricity practically to this purpose have been more or less unsuccessful.
According to one arrangement that has been proposed the hides or skins are placed,
along with a suitable tanning solution, in a revolving drum provided with suitable
means for passing a current of electricity through its liquid contents. In order to
prevent the escape of liquid from this drum the latter has to be hermetically closed
during the operation; and as certain gases are evolved by the decomposition of the
water in the liquid by the electric current or otherwise, the accumulation of such
gases in the said drum is liable to engender sufficient pressure to burst the same,
whereby not only is material lost but serious danger is occasioned to operatives and
other persons employed in the manipulation of such apparatus. The object of my
invention is to obviate these defects and for this purpose I employ an open tank or
other suitable vessel containing the tanning solution. In this tank, and more or less
immersed in the liquor contained therein, I place a rotating drum or cage composed
of bars secured to suitable framework, or otherwise constructed in such manner that
as the said drum or cage rotates in the liquid contained in the tank the said liquid is
free to pass in and out of the said drum or cage, and any gas generated is free to
escape therefrom, and from the tank without producing undue pressure in either. The
drum or cage may be arranged to rotate horizontally or vertically, and is adapted to
receive within it the hides or skins to be tanned, and which are kept in motion in the
liquid by the rotation of the said drum or cage. When the drum or cage is arranged
to rotate on a horizontal axis its interior is preferably provided with wooden pegs
projecting radially inwards from 2 to 4 inches in length, and placed about 3 inches

page_text: apart. These pegs are intended to keep the hides or skins away from the internal
surface of the drum or cage, and to assist in preventing the hides or skins from
rolling up into a ball shape as they are carried round by the drum or cage. When
the drum or cage is arranged to rotate on a vertical axis its horizontal ribs or bars
may be provided with pegs on which the hides or skins are hung, and by which they
are carried round and round through the liquid, so as to offer continually, fresh
surfaces to the action thereof. Instead of a drum or cage simple frame work may be
employed connected to a central revolving shaft, and provided with pegs or pins for
carrying or supporting the hides or skins as in the case of the drum or cage. Or the
framework may have imparted thereto a reciprocating or other motion as may be
preferred.
Suitable electrodes are provided in the tank or in or on the drum, cage, or framing
and connected with a dynamo or other source of electricity, for the purpose of passing
a current of electricity through the liquid in the tank while the drum, cage or framing
is in motion.
The tank is by preference provided with a tap for drawing off the liquid when the
tanning operation is complete; and the drum or cage with means for obtaining access
to the interior thereof for the introduction to and removal therefrom of the hides or
skins when required. The tank may also be provided with a lid or cover, which may
be furnished with a safety valve especially when it is required that the evolved gases
shall act upon the hides or skins under treatment..
Instead of a special tank as above described an ordinary tan pit may be used to
receive the revolving drum, cage or framing and it will be understood that any suitable
means may be employed for imparting the necessary rotary or other motion to such
drum, cage, or framing.
Dated this Seventeenth day of January 1888.
LORENTZ ALBERT GROTH,
3, Tokenhouse Buildings, London, E.C.

page_text: COMPLETE SPECIFICATION.
Improved Apparatus for Tanning Hides and Skins by the Aid of
Electricity.
I, LORENTZ ALBERT GROTH, of 3 Tokenhouse Buildings, in the City of London,
Civil Engineer, do hereby declare the nature of the said invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying two sheets of
Drawings and to the letters and figures marked thereon that is to say :-
It is well known that if a sufficiently powerful current of electricity be passed
through the tanning liquor in which hides or skins are being tanned the process of
tanning is thereby hastened but so far as I am aware all the means heretofore proposed
for applying electricity practically to this purpose have been more or less unsuccessful.
According to one arrangement that has been proposed the hides or skins are placed,
along with a suitable tanning solution, in a revolving drum provided with suitable
means for passing a current of electricity through its liquid contents. In order to
prevent the escape of liquid from this drum the latter has to be hermetically closed
during the operation; and as certain gases are evolved by the decomposition of the
water in the liquid by the electric current or otherwise, the accumulation of such
gases in the said drum is liable to engender sufficient pressure to burst the same,
whereby not only is material lost but serious danger is occasioned to operatives and
other persons employed in the manipulation of such apparatus.
The object of my invention is to obviate these defects, and for this purpose I
employ apparatus such as is illustrated in the Drawings hereto annexed, in which
Figures 1 and 2 are respectively longitudinal and transverse sectional elevations of one
form of the apparatus, and Figures 3 and 4 respectively a vertical sectional elevation
and a plan of another form of same.
Referring to Figures 1 and 2, A is a tank or other suitable vessel containing the
tanning solution. In this tank, and more or less immersed in the liquor contained
therein, I place a rotating skeleton or open case or cage composed of bars B secured to
suitable framework ends C, or otherwise so constructed that as the said cage rotates in
the liquid contained in the tank A the said liquid is free to pass in and out of the said
cage, and any gas generated is free to escape therefrom and from the tank A through
a hole in the cover D, or through a safety valve applied thereto, without producing
undue pressure in either. The cage may be arranged to rotate on horizontal axes E
as shown, or on a vertical axis if preferred, and is adapted to receive within it the
hides or skins to be tanned, and which are kept in motion in the liquid by the rotation
of the said cage.
When the said cage is arranged to rotate on a horizontal axis as in
the Figures, the bars B are preferably provided with wooden pegs F projecting radially
inwards from two to four inches in length, and placed about three inches apart.
These pegs are intended to keep the hides or skins away from the internal surface of
the bars of the cage, and to assist in preventing the hides or skins from rolling
up into a ball shape as they are carried round by the cage. When the cage is

page_text: arranged to rotate on a vertical axis horizontal ribs or bars are provided therein
furnished with pegs, pins or hookes on which the hides or skins are hung, and by
which they are carried round and round through the liquid, so as to present
continually fresh surfaces to the action thereof.
N and P are electrodes connected with a dynamo or other suitable source of
electricity for the purpose of passing a current of electricity through the liquid in
the tank A while the cage is in motion. These electrodes may be carried by the cage
so as to rotate therewith, suitable means being provided for maintaining their con-
nection with the source of electricity while the cage is revolving but I prefer to
employ the arrangement shown in the Figures.
The tank A is preferably provided with a tap G for drawing off the tanning liquid
when the tanning operation is complete; and the cage with removeable parts or
other means whereby access can be obtained to the interior thereof for the introduction
to, and. removal therefrom of the hides or skins when required. The tank may be
provided with a lid or cover D especially when it is required that the evolved gases
shall not escape too freely from the tank. The cover D may be provided with a safety
valve as above described to prevent the accumulation of too great pressure of gas in
the tank.
Instead of a skeleton case or cage as above described, and illustrated in Figures 1
and 2, the arrangement shown in Figures 3 and 4 may be employed if preferred. A
is a tank as before containing the tanning solution. B is a framework connected to
and revolving with a central shaft E and provided with bars B¹ furnished with pegs,
pins or hooks to which the hides or skins are suspended so as to hang down in the
tanning liquid. N and P are electrodes connected with a suitable source of electricity
as is the case of the cage shown in Figures 1 and 2.
Instead of a special tank A as above described an ordinary tan pit may be used
to receive the revolving cage, or framing, and it will be understood that the necessary
rotary or other motion may be imparted to such cage or framing by worm gearing
as shown in Figures 1 and 2, by toothed wheel work or other suitable gearing, or
direct by belting or otherwise as may be most convenient.
The cage or framing may be made to rotate continuously in one direction or
alternatively in opposite directions, and instead of rotary framing or bars as shown
in Figures 3 and 4, frames or bars on which the hides or skins are hung may be
caused to reciprocate in a rectilinear or other direction so as to move the hides or
skins to and fro in the tanning liquid while the electric current is acting thereon.
The apparatus is employed as follows:-
A number of hides or skins are placed loosely in the cage if the latter rotates on
a horizontal axis, or are hung on the pegs, pins or hooks of such cage if it rotates on
a vertical axis, or on the pegs, pins or hooks of the rotating or reciprocating frame
or bars. Tanning liquor is then admitted to the tank A until the hides or skins are
immersed in such liquor. The cage, framing or bars and consequently the bides or
skins therein, or hung thereon, are set in motion and the electrodes N P are connected
to the source of electricity so that a current of electricity is passed through the
liquid. The motion of the cage, framing or bars and of the hides or skins is con-
tinued for about four days, more or less according to circumstances, the current of
electricity being maintained during that time, or during a part thereof only,
according to circumstances and as may be necessary for the materials under treat-
ment; at the end of that period the tanning of the hides or skins will be completed;
the motion of the apparatus is then arrested, the current of electricity stopped, if
it has not been previously stopped, the tanning liquor drawn off from the tank A by
the tap G or otherwise and the tanned hides or skins removed. Fresh hides or skins
are then put in, and the cycle of operations repeated, and so on continuously.
With the apparatus above described I am enabled to effect the tanning of hides
or skins by the aid of electricity much more rapidly than can be effected by the
ordinary process of tanning, and without the danger of explosion to which closed
revolving drums are, as above mentioned, liable; whilst the apparatus, containing or
carrying the hides or skins, not requiring to be watertight as it revolves or otherwise

page_text: moves in the tanning liquid, is much easier and more cheaply constructed, does not
require to be so strong and heavy, requires less power to operate it, and is simpler
to manipulate than the aforesaid closed drum arrangement.
The cage, framing or bars are preferably made of timber but other suitable material,
which will not act injuriously on the tanning materials, may be employed.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I would have it
understood that I do not claim broadly the use of electricity in tanning or apparatus
for keeping the hides or skins in motion in the tanning liquid, but I declare that what
I do claim is :-
First Apparatus for tanning hides or skins wherein are employed skeleton cases
or frames for receiving and keeping the hides or skins in motion, also a tank or tan
pit containing the tanning liquid in which the hides or skins are immersed and kept
in motion, and also electric appliances for passing a current of electricity through
the tanning liquid substantially as hereinbefore described, and illustrated in the
Drawings hereto annexed.
Second-The combination of parts forming apparatus for tanning hides or skins
which consists of a rotating or reciprocating skeleton case or cage of open framework
containing the hides or skins to be tanned, and immersed and moving in the tanning
liquid contained in a tank or in a tan pit, in combination with electric appliances for
passing a current of electricity through the tanning liquid as hereinbefore described,
and illustrated in the Drawings hereto annexed.
Third The apparatus for tanning hides or skins which consists of a rotating or
reciprocating framing or series of bars on which the hides or skins to be tanned are
hung whilst immersed and moving in the tanning liquid contained in a tank, or in
a tan pit, in combination with electric appliances for passing a current of electricity
through the tanning liquid as hereinbefore described, and illustrated in the Drawings
hereto annexed.
Dated this Seventeenth day of October 1888.