IMPROVEMENTS IN ENAMELLING METAL CASTINGS
Year: 1879

page_text: LETTERS PATENT to Carl Kesseler, of 63, Mohrenstrasse, Berlin, W., in the
Empire of Germany, Civil Engineer and Patent Solicitor, for the Invention of
"IMPROVEMENTS IN ENAMELLING METAL CASTINGS." A communication from
Nicolaus Henzel, Engineer, of Prag, and Ladislaus Broz, Chemist, of Rokycan,
both in the Austro-Hungarian Empire.
Sealed the 23rd January 1880, and dated the 28th July 1879.
PROVISIONAL SPECIFICATION left by the said Carl Kesseler at the Office of
the Commissioners of Patents on the 28th July 1879.
CARL KESSELER, of 63, Mohrenstrasse, Berlin, W., in the Empire of Germany,
Civil Engineer and Patent Solicitor. "IMPROVEMENTS IN ENAMELLING METAL
CASTINGS." A communication from Nicolaus Henzel, Engineer, of Prag, and
Ladislaus Broz, Chemist, of Rokycan, both in the Austro-Hungarian Empire.
The Invention has for its object the cheap enamelling of metal castings, especially
iron pipes, and consists in producing an enamelled surface during the process of
casting in the following manner :-For producing internally enamelled cast-iron
pipes the mould and core are first made in the ordinary manner, after which
the [core is coated with black lead and carefully smoothed. Subsequently the
core is provided with an uniform layer of any suitable enamelling substance,
either as a paste which must then be dried, or as a powder on the moist clay-core.
If the enamelled surface need not be very smooth the black-lead coating may
be omitted for sand-cores. The cores so treated are dried at a slowly increasing
temperature and laid in the dry moulds, after which the iron is cast in the
mould and left to cool. In this way various metal castings may be internally
or externally enamelled, and if desired, at the same time coloured by the application
of enamelling substances which possess the required colour. As enamelling substances
all ingredients which develop gases when coming into contact with the molten iron
must be avoided, potash, soda, lime, and silica, also alumina and boracic acid, being
found most suitable for this purpose. The enamelling substance may for instance
be obtained by melting together 28 parts of silica (quartz), 11 parts of carbonate of
soda, and 6 parts of carbonate of lime, all these ingredients being assumed as free
from water, powdered and treated in the usual way. In order to increase the
adhesion on the core or mould the enamelling substances may be mixed with pipe-
clay or other suitable additions.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Carl Kesseler in the Great Seal Patent Office on the 23rd January
1880.
CARL KESSELER, of 63, Mohrenstrasse, Berlin, W., in the Empire of Germany,
Civil Engineer and Patent Solicitor. "IMPROVEMENTS IN ENAMELLING METAL
CASTINGS." A communication from Nicolaus Henzel, Engineer, of Prag, and
Ladislaus Broz, Chemist, of Rokycan, both in Austro-Hungarian Empire.
The Invention has for its object the cheap enamelling of metal castings, especially
iron pipes, and consists in producing an enamelled surface during the process of
casting in the following manner :—
For producing internally enamelled cast iron pipes the mould and core are first
made in the ordinary manner, after which the core is coated with black-lead and
carefully smoothed.
, Subsequently the core is provided with a very uniform layer of any suitable
enamelling substance, either as a paste (prepared with water) which must then be
dried, or as a powder (thrown and burnished) on the moist clay-core. If the enamelled
surface need not be very smooth, and sand cores are used, the black-lead coating
may be omitted. The cores so treated are dried at a slowly increasing temperature
and laid in the dry moulds so as to prevent the reabsorption of moisture.
The process of casting must be very smooth and even, which precludes the
application (as enamelling substances) of ingredients which emit gases or vapours
when coming into contact with the molten iron.
The molten iron causes the enamelling or glazing substances to melt, whereby the
connection between the iron and the enamel taking place at a higher temperature
becomes much more intimate than that obtained by the ordinary method of
enamelling. The articles thus enamelled remain in the mould until the ordinary
temperature of the atmosphere ceases to have an injurious effect on the enamel.
In this way various metal castings may be internally or externally enamelled, and
if desired colored at the same time by the application of enamelling substances
which possess the required color.
The enamelling substances consist chiefly of potash, soda, lime, and silicic acid;
alumina, and boracic acid may sometimes also be used. Suitable compositions may
for instance be obtained :-
1. By melting together 28 parts (in weight) of silicic acid (quartz), 11 parts of
carbonate of soda (calcined soda), and 6 parts of carbonate of lime.
2. By melting together 34 parts (in weight) of silicic acid, 11 parts of carbonate
of soda, and 12 parts of carbonate of lime.
3. By melting together 34 parts of silicic acid, 11 parts of carbonate of soda, and
12 parts of carbonate of lime, and 5 parts of air dried pipe clay free of lime.
4. By melting together 34 parts of silicic acid, 6 parts of carbonate of soda, and
12 parts of carbonate of lime.
In all these instances the silicic acid, carbonate of soda, and lime are supposed to
be free of water.
The treatment of these substances is the same as that hitherto applied for
enamelling substances (and which consists in pulverizing, mixing, grinding, etc.),
According to the nature of the castings to be enamelled the materials described
are mixed with substances which increase the adhesion between the enamel and the
core or mould. Pipe clay, burnt or unburnt, but preferably unburnt, is in most
cases suitable for this purpose.
For producing highly finished enamel castings, and also for cooking vessels, the
enamel cast on as described may be used as a first coating, which is subsequently
covered in the ordinary manner by a second coating. In this case the surface of

page_text: CLAIM.
The production of enamelled or glazed surfaces on iron (or other metal) castings
by coating the respective surfaces of the mould or core with any suitable enamelling
or glazing substance so that the molten iron (or other metal) causes the said
substance to melt and to adhere to the surface of the metal casting, for the purpose
of manufacturing cheap enamelled castings in the manner substantially as described.
In witness whereof, I, the said Carl Kesseler, have hereunto set my hand
and seal, this Eighteenth day of January, A.D. 1880.