Desuverising Lead.
Year: 1885

page_text: Desuverising Lead.
I, JAMES CARTMELL RIDLEY of 3 St. Nicholas Buildings in the City and County
of Newcastle upon Tyne, Steel Manufacturer, do hereby declare the nature of Baid
invention for "IMPROVEMENTS IN THE MANUFACTURE OF POTS FOR MELTING AND
DESILVERISING LEAD," to be as follows:-
The object of my invention is to produce melting and desilverising pots used in
the manufacture of lead, hitherto and now usually made of cast iron, so as to secure
lightness, strength and durability. It is well known that the duration of these
pots principally depends upon the ability of the material to withstand the
expansion and contraction due to the variations of temperature.
The thickness in cast iron requires to be excessive and the regularity of quality
of cast iron pots, even of the most approved mixture, is most uncertain, as is the
duration of time before they ultimately fail.
According to my invention I make the pots of steel of suitable quality as to
tenacity and ductility (and if necessary anneal them) or of steel containing such a
small percentage of carbon as to be called homogeneous iron.
They will generally be cast in moulds but they may also be produced by forging
or by stamping.
In making these pots of cast steel, or homogeneous iron, I propose to make them
considerably thinner than they are now made of cast-iron of, however sufficient
strength to sustain the charges of lead under the required temperature.
'I propose to vary the proportions of carbon, manganese or other constituents so
as to produce steel of varying qualities according to the requirements of the
particular process for which they are to be employed and to other conditions.
Dated this 3rd day of March 1885.
W. LLOYD WISE,
Applicant's Agent,

page_text: I JAMES CARTMELL RIDLEY of 3 St Nicholas Buildings, in the City and County
of Newcastle upon Tyne, Steel Manufacturer, do hereby declare the nature of this
invention to be particularly described and ascertained in and by the following
statement.
The object of my invention is to produce pots, used in the processes of melting
and desilverising lead; of greater and more uniform durability and much stronger
in proportion to weight than those now used of cast iron.
It is well known that the duration of these pots principally depends upon their
ability to withstand the expansion and contraction of the material, caused by the
variations of temperature to which they are subject.
Their thickness in cast iron, to give the necessary strength, involves great weight
and the regularity of quality of cast iron pots, even of the most approved mixtures,
is most uncertain as is also the duration of time before they fail.
Being fully aware of these defects I came to the conclusion that they might be
obviated by the use of pots made of cast steel of suitable quality as to tenacity and
ductility, or of cast steel containing so small a per centage of carbon as to be called.
homogeneous iron, in either case annealed if necessary.
I have since found by practical trials my conclusion fully borne out with a pot
I have had at work for several months under the most trying conditions This pot
is also considerably lighter being, as compared with those ordinarily used, only
about one half the weight.
The reduced thickness is an advantage in facilitating the transmission of heat
through the pot to the contained lead but I attribute its durability to the tenacity
of the steel enabling it to resist the expansion and contraction without fracture.
Such steel pots will be generally made by casting in moulds or they may
be produced by forging or by stamping from "blanks" previously cast of
approximately the required form.
The proportions of carbon, silicon, manganese or other constituents may be
varied so as to produce steel of varying qualities according to the requirements of
the particular process for which they are to be employed and to other conditions.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I desire it to be
understood that I make no general claim for making pots or similar vessels, used
for other processes, of steel but what I do claim is
In the processes of melting and desilverising lead the use of pots of cast steel (or
of steel in the mild form known as homogeneous iron) for the purpose of securing
lightness and capability of resisting destruction. by expansion and contraction
substantially as described.
T