Year: 1886

page_text: Date of Application, 12th Nov., 1886.
Specification Accepted, 13th May, 1887,
We, JOHAN WILHELM ABOM and JOHN LANDIN, both of Stockholm, in the
Kingdom of Sweden, Engineers, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly describod and
ascertained in and by the following statement :-
The object of this invention is to facilitate and to hasten the tanning of hides and
skins by the employment of alternate currents of electricity. It is well known that
when tanning with any tanning material the said tanning material is forced into the
pores of the hide by capillary action and endosmose. By causing an electric current
to pass through a solution in which the hide is placed, the capillary action as well as
the diffusion is increased. The constant of capillary action varies with the difference
of the electric tension between two points in the solution, so that the greater this
difference is, the greater becomes the constant, at least within certain limits. The
diffusion is also promoted by the electric current which for example is proved by
its power of increasing the exchange of solutions through the porous partition
(diaphragm) in the galvanic elements. The power possessed by the positive current
of bringing matter along in its passage is also of great importance.
The arising of gases and the oxidation and loss of tannin (tanning materials)
resulting therefrom (which is the case with currents running only in one direction)
is obviated by the use of alternate currents whereby we cause an increase of the
capillary action and endosmose which effect the tanning while the loss of tannin
(tanning materials,) that would be caused by the arising of gases is avoided.
The tanning is effected by placing the hide in the solution of tanning materials
whether organic or inorganic, between two electric poles, for example two copper
plates, which are submerged in the solution connected with the circuit in which the
alternate currents run.
It will be obvious that in carrying out our invention one or more hides can be
placed between the poles and that the poles may be arranged in different ways,
for example, the vessel in which the tanning is to be effected can be made of metal,
which may serve the purpose of one pole. Also one or more. portions of the vessel
can be made of metal and the said portion or portions can serve as one or both poles.

page_text: Or the poles can be placed either side by side or one above the other, or in any other
suitable position.
For the generation of the alternate currents galvano-electric or thermo-electric
elements or dynamo-electric or magneto-electric machines can be employed either
separately or in combination with induction coils; or other suitable means for
generating electric currents may be employed.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to he performed we declare that what we claim is :—
The herein described method of tanning hides and skins consisting in placing them
between electric poles in a solution of tanning materials between which poles alternate
electric currents are caused to pass.
1
1000
G. F. REDFERN,
4, South Street, Finsbury, London,
Agent for the Applicants.