Year: 1886

page_text: I DESMOND GERALD FITZ GERALD of 6 Akerman Road, Brixton in the County
of Surrey, Electrician do hereby declare the nature of this invention to be as
follows:-
This Invention relates to the manufacture of plates, slabs, and masses mainly
composed of peroxide of lead in a dense and coherent form and suitable for use
as negative elements in voltaic batteries without contact with any oxidisable
material. In lead secondary batteries of the ordinary form wherein contact with
the oxidisable metal lead obtains, the two substances mutually destroy each
other, the peroxide oxidising the lead support, and the latter converting the
valuable peroxide into the inert monoxide. The elements to be described have
the great advantage of being free from this cause of deterioration.
It has before been proposed to employ glycerine in admixture with oxide of lead
for the manufacture of negative elements for voltaic batteries, but I have experi-
mentally found that a mixture of glycerine with about twice its volume of water,
or of a half saturated solution of sulphate of ammonia, or of one of the other
solutions specified in my former application for Letters Patent (No. 4671 of 1885)
or again, of a solution of an acid, such as sulphuric or phosphoric acids, gives better
results than glycerine alone in admixture with oxide of lead. The advantage is to
be attributed to the fact that with the fluid mixtures employed by me, the
resulting compound of lead is hydrated, whereas when glycerine alone is used the
resulting compound is necessarily anhydrous.
In carrying out my Invention I mix oxide of lead with a fluid mixture of
glycerine and water, or with glycerine and the solution of a suitable salt, or with
glycerine in admixture with a suitable acid, and I form plates, slabs, or masses of
one of these compositions which speedily harden and are afterwards converted
into peroxide by either of the two processes described in the specification of my
former application above referred to, or preferably by the two processes conjointly,
i.e. "browning" by means of hypochlorite of magnesium or other suitable chlorine
compound, and completing the conversion by electrolysis.
My Invention also relates to the production of a compound element consisting
originally of a central core or support of the glycerine and oxide of lead above
referred to, and with external layers of one of the more porous and more readily
convertible oxide of lead compositions specified in my previous application.

page_text: In mounting the negative elements with a suitable contact piece of carbon, or of
an insulating material carrying strips of platinum, but more particularly in the
former case, I find it advantageous to prepare or coat that portion of the surface of
the plate where contact is to be established with plumbago or black lead, the
minute quantity of plumbago thus employed filling the pores in the plate and
rendering it easy to establish a more perfect contact with the plate than would
otherwise be possible.
D. G. FITZ GERALD.
By A. M. & Wm. Clark,
Patent Agents,
53, Chancery Lane, London,
I, DESMOND GERALD FITZ-GERALD of 6 Akerman Road Brixton in the County
of Surrey, Electrician, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This Invention relates to the manufacture of plates, slabs, and masses, mainly
composed of peroxide of lead in a dense and coherent form and suitable for use
as negative elements in voltaic batteries without contact with any oxidizable
material.
In the negative element of lead secondary batteries of the ordinary form
wherein contact with the oxidizable metal-lead-obtains, the two substances
mutually destroy each other, the peroxide oxidising the lead support and the latter
converting the valuable peroxide into the inert monoxide. The elements to be
described have the great advantage of being free from this cause of deterioration.
It has before been proposed to employ glycerine in admixture with oxide of
lead for the manufacture of negative elements for voltaic batteries but I have
experimentally found that a mixture of glycerine with about twice its volume
either of water, or of a half saturated solution of sulphate of ammonia, or of one
of the other solutions specified in my former Letters Patent (No. 4671 of 1885) or,
again, of a solution of an acid forming an insoluble or nearly insoluble salt of lead
(such as sulphuric or phosphoric acids) gives better results than glycerine alone
in admixture with oxide of lead. The advantage is to be attributed to the fact
that with the aqueous mixtures employed by me the resulting compound of lead

page_text: is hydrated, whereas when glycerine alone is used the resulting compound is
necessarily anhydrous.
In carrying out my Invention, I mix oxide of lead with a mixture of glycerine
and water, or with glycerine and the solution of a suitable salt, namely, any one of
the salts specified in my former Patent aforesaid, or with glycerine in admixture
with a suitable acid as aforesaid, and I form plates slabs or masses of one of these
compositions which speedily harden and may be afterwards converted into peroxide
by either of the two processes described in the specification of my former Patent
above referred to, or preferably by the two processes conjointly; i: e: "browning
by means of hypochlorite of magnesium or other suitable chlorine compound, and
completing the conversion by electrolysis.
"
My Invention also relates to the production of a compound peroxide of lead
element consisting of a central core or support of either of the glycerine and oxide
of lead compounds above referred to, with an external layer or layers of one of the
more porous and more readily convertible oxide of lead compositions specified in
the Specification of my previous Patent.
The method of construction I preferably adopt is as follows; reference_being
had to the accompanying drawings forming part of this specification-First, I form
in a suitable mould a plate a with apertures or perforations (as shewn in face view.
in figure 1) composed of oxide of lead made into a paste with any of the glycerine
mixtures above referred to. Secondly when this plate has hardened sufficiently
I convert the plate, at least superficially, into peroxide of lead by either or both of
the two processes above referred to. Thirdly I attach to the peroxidized plate by
means of ebonite screws passing through the apertures bb and 61 6¹ and secured
by ebonite nuts, the contact piece of which an inside face view is shewn in
figure 2. This consists of a thin strip of ebonite c (or other suitable material not
acted upon by dilute sulphuric acid and not readily oxidized) to which may be
attached, by cementing or otherwise, a piece of metal (which may be copper
protected from corrosion by an insulating material) to which one or more strips ce
of platinum is or are metalically connected, the strip or strips extending along the
inner face of the ebonite strip so as to be thereby pressed into direct contact with
the peroxidized plate. The strip or strips lie across notches f (or it may be
apertures as shown on an enlarged scale in figure 3) in the ebonite strip so as to
expose a portion of the outer surface of the platinum strips for contact with the
external layer g of lead composition next referred to. Fourthly I coat to any
required thickness one or both of the sides of the superficially peroxidized plate
with a layer g of any of the porous and readily peroxidized oxide of lead
compositions specified in my previous Patent above referred to. This composition,
which also covers the contact piece, is pressed through the holes or notches f to
make contact with the platinum strips, as shewn on an enlarged scale in figure 4,
which is a cross section of part of the compound structure. It may be applied
either in the form of a paste or as a powder which, after being subjected to a slight
compression, is moistened by suitable means-as by water spray, water condensed
from steam, or by imbibition through porous plates by which the mixture may be
contined. Lastly, the porous composition is converted into peroxide of lead by
being made the anode in a suitable electrolyte, as is well understood. By making
contact directly with the superficially peroxidized core as above described I obtain
a conductive surface of large area from which the subsequent conversion of the
external layer may be rapidly initiated.
I would have it understood that although I, for this reason, find it advantageous
to embed the contact piece so as to make contact both with the core and with the
external layer, I do not limit myself thereto, but may make contact with the
exterior of the compound plate in the ordinary way.
I find it advantageous to prepare or coat that portion of the surface of a
peroxide of lead element where contact is to be established, with plumbago or
black-lead, the minute quantity of plumbago thus employed filling the pores in
the plate and rendering it easy to establish a more perfect contact with the plate

page_text: than would otherwise be possible, whether such contact be effected by platinum
strips as above described, or by means of a contact piece made of carbon.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, I declare that what
I claim is;-
.
1. In the manufacture of peroxide of lead elements for voltaic batteries, the
production of a hydrated compound of oxide of lead and glycerine by making the
lead oxide into a paste with a fluid composed of glycerine in admixture either
with water, or with a saline solution, or with a dilute acid, as and for the purpose
specified.
2. The manufacture of a compound structure to be converted into a peroxide of
lead element, consisting of a superficially peroxidized central core or support of
either of the oxide of lead and glycerine compounds specified, coated with an
external layer or layers of one of the more porous and readily convertible oxide of
lead compositions referred to, substantially as specified.
3. In the manufacture of a compound structure for a peroxide of lead element
as herein specified, the combination with a superficially peroxidized central core
composed of either of the lead oxide and glycerine compositions specified, and with
an external layer or layers composed of a different oxide of lead compound as
specified, of a contact strip or strips of platinum in contact both with the
peroxidized surface of the core and with the external layer as specified.
4. A peroxide of lead element having that part of its surface where contact is to
be made prepared or coated with plumbago or black lead as specified.
13
1
1
1000
D. GERALD FITZ GERALD.
By A. M. & Wm. Clark,
Patent Agents,
53, Chancery Lane, London.