Improvements in the Manufacture of Reflecting Opalescent Surfaces for Electric Lamps or Glass Reflectors.
Year: 1899

page_text: Date of Application, 18th Oct., 1899
Complete Specification Left, 6th July, 1900-Accepted, 6th Oct., 1900
Improvements in the Manufacture of Reflecting Opalescent Surfaces
for Electric Lamps or Glass Reflectors.
We, THE IMPROVED ELECTRIC GLOW LAMP COMPANY, LIMITED, Lamp Manu-
facturers, and ALBERT BARNES, Electrical Engineer, all of 103, Queen Victoria
Street, London, E.C., do hereby declare the nature of this invention to be as
follows:-
This invention relates to the production of an opalescent reflecting surface
(which may be either translucent or opaque) upon glass, such as upon electric
lamp bulbs, lamp globes, or other glass surfaces, and has for its object the
application of such a reflecting surface with ease, simplicity and cheapness upon
the glass article or surface after manufacture, and thus avoiding the joining
of diverse glasses or crystals in the course of manufacture and the flashing of
part of a clear glass bulb, globe, or surface to render the same opalescent, as
has heretofore been the practice.
To carry this invention into effect we grind together and carefully mix
cryolite, oxide of zinc, or sulphate of barium, opal glass, and silicic acid or
silica, and reduce these bodies when ground to fine powder to the consistency
of cream by a solution of potassium or sodium silicate, the former being pre-
ferred, as making the expansive ratio of the composition when dry as nearly as
possible equivalent to that of the glass used in the production of such glass
bulbs or globes.
By the use of the silicic acid in the composition we neutralize the hygroscopic
effect of the alkaline solution and impart great hardness to the composition
when dry.
The composition as above described which is white may be modified by pig-
ments or other coloured minerals to take any required tint.
The above composition may be applied cold to the glass surface which is to be
rendered opalescent.
This may be done in the case of an electric bulb by dipping the lamp into
the composition whilst the former is revolving; or the composition may be
applied by a brush, pads, or rollers fed with the composition, as in the case of
printers ink to printing machines, whilst the surface to receive the composition
is kept in motion to uniformly distribute the same.
The composition dries rapidly and leaves a hard opalescent surface which is
proof against moisture or acids, but as a further protection we may apply by
means of heat a thin coating of paraffin wax polishing off any excess.
We may also apply an external glaze of any sort to the composition when
dry such as gelatine treated with formalin.
Dated this 18th date of October 1900

page_text: globes of electric lamps with an opalescent or opaque reflecting surface without
the use of heat, consisting of finely ground cryolite, opal glass and silicic acid
or silica mixed with a solution of silicate of potassium or sodium, in the pro-
portions approximately as specified, to produce a hard, smooth, opaque, or trans-
lucent surface, upon the glass, capable of resisting, when dry, moisture, heat,
or acids, substantially as described.
2nd. In a composition for producing a hard opaque or translucent surface upon
glass, capable of resisting, when dry, heat acids and moisture, the admixture
with a finely ground silicate and a fluoride in an alkaline silicate solution, of
free silicic acid or silica, with any added colouring matter such as oxide of zinc
or sulphate of barium and pigment substantially as described.
Dated this 6th day of July 1900.
FELL & JAMES,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.