IMPROVEMENTS IN COATING SHEETS OF IRON AND COPPER WITH LEAD
Year: 1878

page_text: LETTERS PATENT to Gerard Wenzeslaus von Nawrocki, of the 'irm of Brandt
and v. Nawrocki, of 124, Leipzigerstrasse, Berlin, Germany, Patent Agents,
for the Invention of "IMPROVEMENTS IN COATING SHEETS OF IRON AND
COPPER WITH LEAD." A communication from abroad by William Thorn, of
Montpellier, France.
Sealed the 29th April 1879, and dated the 2nd November 1878.
PROVISIONAL SPECIFICATION left by the said Gerard Wenzeslaus von
Nawrocki at the Office of the Commissioners of Patents on the 2nd November
1878.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of Brandt and v. Nawrocki,
"IMPROVEMENTS IN
of 124, Leipzigerstrasse, Berlin, Germany, Patent Agents.
COATING SHEETS OF IRON AND COPPER WITH LEAD." A communication from
abroad by William Thorn, of Montpellier, France.
In the manufacture of a great many chemical substances, such as sulphuric, nitric,
muriatic, citric, vinous, oxalic, or stearic acids, alum, iodine, and bromine, various
apparatus made of lead are used; the softness and weakness of this metal are
objectionable, and it is unsuitable where any considerable pressure is applied, and
for vacuum or distilling apparatus.
The object of this Invention is to overcome these difficulties, and to construct
boiling backs, crystallizing pans, acid tanks, "Montejus," vacuum apparatus, distil-
ling apparatus, and other similar apparatus, and parts used for acid fluids, or gases
of lead, coated iron, or copper plates instead of lead, whereby a much more durable
material is obtained, and one suitable for considerable pressure.
The coating with lead for the above purposes is eflected as follows:-The sheets
to be coated are first cleaned in any suitable acid bath to remove scales or other
oxide or other impurities; for iron a thin muriatic acid solution, with a little zinc
dissolved in it, is suitable. The plates are theu well tinned in the ordinary manner,
but only on one side of the sheet. The so tinned sheets, in a perfectly clean dry

page_text: state, are then placed perfectly horizontal, and surrounded with an edge or wall of
and, and in this position heated by any suitable heating appliance; an adjustable
gas heating appliance is very suitable for the purpose. This heating is continued
until the tin coating-melts, and then_molten lead is poured on in the thickness or
quantity which is required, according to the purpose for which the plate is intended;
the lead should be as free from oxide as possible. The metal is allowed to flow all
over the tinned surface, and amalgamates with the thin tin coating. It is a necessary
condition that the sheet, until the tin coating begins to melt, should be heated to
about 430 to 450° Fahrenheit. Small irregularities, which arise in the pouring, are
removed by hammering, which gives the lead a greater density than rolled lead, and.
by rolling by means of ordinary sheet iron rolls, whereby at the same time the lead
coating-can be reduced to a minimuni.
Lead coated sheets so made may be worked in any way, such as bent, rivetted,
hammered, without any separation of the lead from the other metal, and they are
extremely lasting for the above named purposes because of the purity and density
of the lead. As required, in some constructions of the apparatus, the sheets may
be provided with overlapping lead edge.
Apparatus which are to sustain a very high pressure, and which, because of the
great iron or copper thickness, could not without damage to the strength of the
metal be bent cold, may be coated with lead by the use of a mould or core placed
in the manufactured apparatus, and by pouring the lead in between a space left
between the plate and the mould or core.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
'by the said Gerard Wenzeslaus von Nawrocki in the Great Seal Patent Office
on the 2nd May 1879.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of Brandt and v. Nawrocki,
of 124, Leipzigerstrasse, Berlin, Germany, Patent Agents. "IMPROVEMENTS IN
COATING SHEETS OF IRON AND COPPER WITH LEAD." (A communication from
abroad by William Thorn, of Montpellier, France.)
In the manufacture of a great many chemical substances, such as sulphuric, nitric,
muriatic, citric, vinous, oxalic, or stearic acids, alum, iodine, and bromine, various
apparatus made of lead are used; the softness and weakness of this metal are
objectionable, and it is unsuitable where any considerable pressure is applied, and
for vacuum or distilling apparatus.
The object of this Invention is to overcome these difficulties, and to construct
boiling backs, chrystalizing pans, acid tanks, Montajus, vacuum apparatus, distilling
apparatus, and other similar apparatus, and parts used for acid, fluids, or gases of
lead, coated iron, or copper plates instead of lead, whereby a much more. durable
material is obtained, and one suitable for considerable pressure.
The coating with lead for the above purposes is effected as follows:-
The sheets to be coated are first cleaned in any suitable acid bath to remove scales
or other oxide or other impurities; for iron, a thin muriatic acid solution, with a
little zinc dissolved in it, is suitable. The plates are then well tinned in the ordinary
manner, but only on one side of the sheet.
The so tinned sheets, in a perfectly clean dry state, are then placed perfectly.
horizontal, and surrounded with an edge or wall of sand, and in this position heated
by any suitable heating appliance; an adjustable gas heating appliance is very
suitable for the purpose. This heating is continued until the tin coating melts, and
then molten lead is poured on in the thickness or quantity which is required, accord-
ing to the purpose for which the plate is intended; the lead should be as free from
oxide as possible. The metal is allowed to flow all over the tinned surface, and
amalgamates with the thin tin coating. It is a necessary condition that the sheet,
until the tin coating begins to melt, should be heated to about 430 to 450° F.
Small irregularities, which arise in the pouring, are removed by hammering, which
gives the lead a greater density than rolled lead, and by rolling by means of ordi-
nary sheet iron rolls, whereby at the same time the lead coating can be reduced to
a minimum.
Lead coated sheets so made may be worked in any way, such as bent, rivetted,
hammered, without any separation of the lead from the other metal, and they are
extremely lasting for the above named purposes because of the purity and density
of the lead. As required in some constructions of the apparatus, the sheets may be
provided with overlapping lead edge.
Apparatus which are to sustain a very high pressure, and which, because of the
great iron or copper thickness, could not without damage to the strength of the
inetal be bent cold, may be coated with lead by the use of a mould or core placed in
the manufactured apparatus, and by pouring the lead in between a space left between
the plate and the mould or core.
And having thus described and ascertained the nature of this Invention, and the
best mode of carrying the same into effect, I declare that I claim,-
Coating sheet iron and sheet copper according to the following combined process,
that is, first tinning the one side of the metal, then while heated to a temperature
of about 430 to 450° F. so as to keep the tin coating in a molten state, pouring
upon it liquid lead, and subsequently making the coating dense and sinooth, and of
a required thickness, by haminering and rolling, whereby a material is obtained

page_text: which shall be able to withstand the influence of various chemical substances, while
strong enough to withstand considerable pressure, all substantially as described.
In witness whereof, I,the said Gerard Wenzeslaus von Nawrocki, have hereunto
set-my-hand-and-seal, this Twentyninth_day_of_April, in the year of our
Lord One thousand eight hundred and seventy nine.
GERARD WENZESLAUS VON NAWROCKI. (L.S.)