An Improved Process for the Production of Accumulator Plates.
Year: 1899

page_text: Date of Application, 3rd May, 1899
Complete Specification Left, 3rd Feb., 1900-Accepted, 7th Apr., 1900.
PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Accumulator Plates.
I, ARTHUR LEIMANN, of 32, Andreasstrasse, Berlin; O., in the Empire of
Germany, Chemist, do hereby declare the nature of this invention to be as
follows:-
In order to shorten the time necessary for the production of accumulator
plates and to secure a good layer of lead oxide many experiments have been made
for the transformation of the surface of the electrodes; for example, into chloride
of lead and subsequently to effect oxidation. This process has, however, like
others, the disadvantage that it does not permit of the chloride of lead, or such
like, being entirely converted and consequently difficulties ensue which affect
the durability of the plate, more especially as oxidation subsequently ensues
which should be entirely avoided.
The essential feature of the process according to the present invention consists
in the transformation of the surface of the plates into salts which are easily
soluble, and which leave behind no residuum admixed with the lead oxide.
The process is carried into effect by placing plates of cast or rolled lead into
an electrolyte which is an organic acid of the fatty series. By the application
of an electric current the anode is transformed so that a layer of lead salts is pro-
duced. The plates are thereupon taken out of the electrolyte in order to be
cleaned, rinsed with water and brushed, and are then finally subjected to an
oxidation of the surface layer in an electrolyte of the usual kind. Acids which
may be used for the first transformation may, for example, be formic acid, lactic
acid, butyric acid, acetic acid and oxalic, acid.
MARKS & CLERK,
18. Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents.

page_text: plates and to secure a good layer of lead oxide many experiments have been made
for the transformation of the surface of the electrodes, for example into chloride
of lead and subsequently to effect oxidation. This process has, however, like
others, the disadvantage that it does not permit of the chloride of lead, or such
like, being entirely converted, and consequently difficulties ensue which affect
the durability of the plate, more especially as oxidation subsequently ensues
which should be entirely avoided.
The essential feature of the process according to the present invention consists
in the transformation of the surface of the plate into salts which are easily
soluble, and which leave behind no residuum admixed with the lead oxide.
The process is carried into effect by placing plates of cast or rolled lead into
an electrolyte which is an organic acid of the fatty series. By the application
of an electric current the anode is transformed so that a layer of lead salts is pro-
duced. The plates are thereupon taken out of the electrolyte in order to be
.cleaned, rinsed with water and brushed, and are then finally subjected to an
oxidation of the surface layer in an electrolyte of the usual kind. Acids which
may be used for the first transformation say, for example, be formic acid, lactic
acid, butyric acid, acetic acid and oxalic acid.
The strength of the acid bath I prefer to be such that its specific weight at
45° Centigrade is 1; 12. The lead plates are kept in this bath for about 36 hours.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1.) Forming accumulator plates by treating the surfaces of the plates first in
a bath of an organic acid of the fatty series, thus forming readily soluble lead
salts, then with water, and finally oxidising the plates in an electrolyte of the
usual kind for the production of peroxide of lead, substantially as hereinbefore
described.
Dated this 3rd day of February 1900.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents.