IMPROVEMENTS IN GLASS REFLECTORS FOR GAS AND OTHER LIGHTS
Year: 1882

page_text: LETTERS PATENT to Friedrich Hermann Felix Engel, Civil Engineer and
"
Patent Agent, in the City of Hamburg, Germany, for an Invention of
"IMPROVEMENTS IN GLASS REFLECTORS FOR GAS AND OTHER LIGHTS,"
A communication from Gerson Franke, of Hamburg, in the German Empire.
PROVISIONAL SPECIFICATION left by the said Friedrich Hermann Felix
Engel at the Office of the Commissioners of Patents on the 21st February
1882.
FRIEDRICH HERMANN FELIX ENGEL Civil Engineer and Patent Agent in the
City of Hamburg Germany "IMPROVEMENTS IN GLASS REFLECTORS FOR GAS
AND OTHER LIGHTS." A communication from Gerson Franke of Hamburg in the
German Empire.
This Invention relates to the construction of single walled glass reflectors for gas
and other lights and to the mode of protecting the silver covering against outer
influences and damage. Glass reflectors for lamps have hitherto for that reason
been made double walled with the mirror covering applied to the inner side of one
or both walls enclosing the hollow free space between both walls as no means have
been known to cover and protect the argentation safely against wear and tear or
damage from outer influences. By means of this Invention one walled glass
reflectors of perfect durability and which are not liable to damage of the covering
caused by the heat of the flame or flames may be constructed by applying a coating
of silver to the outer surface of the glass and after drying up of the silver coating
by giving a covering of varnish composed of Shellac, Sandarac, Mastic, Venetian
turpentine and Alcohol. After this coating has sufficiently been dried up a mineral
coating of amber varnish is applied to the article which coating hardens when dry
and gives the reflector a surface of great durability. The amber coating may be
repeated and by using different colours, designs and ornaments can be produced on
the outer side of the glass

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Friedrich Hermann Felix Engel in the Great Seal Patent Office
on the 21st August 1882.
FRIEDRICH HERMANN FELIX ENGEL Civil Engineer and Patent Agent in the
City of Hamburg Germany "IMPROVEMENTS IN GLASS REFLECTORS, FOR CAS
AND OTHER LIGHTS A communication from Gersen Franke of Hamburg in the
German Empire.
12
This invention relates to the construction of single walled glass reflectors for gas
and other lights and to the means for protecting the silver covering against outer
influences and damage. Glass reflectors for lamps have hitherto for that reason
been made double walled with the mirror covering applied to the inner side of one
or both walls enclosing the hollow free space between both walls, as no means have
been known to cover and protect the argentation safely against wear and tear or
damage from outer influences. By means of this Invention one walled glass
reflectors of perfect durability and which are not liable to damage of the covering
caused by the heat of the flame or flames may be constructed by applying a
coating of silver to the outer surface of the glass and after drying up of the silver
coating by giving a covering of varnish composed of Shellac Sandarac Mastic
Venetian turpentine and Alcohol. After this coating has been sufficiently dried a
mineral coating of amber varnish is applied to the article which coating hardens
when dry and gives the reflector a surface of great durability. The amber coating
may be repeated and by using different colours, designs and ornaments can be
produced on the outer side of the glass.
For producing the argentation on the outer side of the glass shade one end of the
_latter is closed by a suitable cover and the shade is then placed into a reservoir or
vat of porcelaine, glass, enamelled iron or other suitable material. The solution of
silver is then poured into the vat and is allowed to act on the glass surface long
enough to form an argentation of sufficient thickness.
The shade is then removed from the silver bath and the coating of varnish is
then applied either by means of a brush or by plunging the shade into a bath of
varnish after having closed the wide end of the shade by a sheet metal box and an
india-rubber cover.
In the accompanying sheet of drawings is represented the mode of manufacturing
the improved reflectors.
Figs 1 2 3 4 5 and 6 illustrate the mode of forming the silver coating and
Figs 7 and 8 the mode of producing the varnish coating.
G is a shade of glass that may be formed in any required size or shape. For
producing the argentation onto the outer surface the top end R is closed by a sheet
metal box m carrying at its bottom a disc b of felt or other suitable soft material
for tightening over the open end by means of a cover c of vulcanized india rubber.
The box m and disc bare pressed against the opening of the shade by screws &
and cross piece D which latter part serves at same time as a handle for placing
the shade into the reservoir or vat A or for removing it from the bath.
Fig. 2 shows the before described parts used for closing the open end of the
shade before being applied thereto, i is a strong rim formed to the india rubber
cover which rim is placed on an india rubber ring v applied to the top part of the
shade for the purpose of securing sharp outlines to the end of the silver coating.
To the wide end of the shade a similar ring z may be applied for the same purpose
which rim prevents precipitation of silver to that part of the shade.
The shade prepared as shown by Fig 1 of the drawings is placed into a vat A

page_text: (Fig. 4) of porcelain or other suitable material and is loaded by a weight s' to keep
it at the bottom of the vat when the liquid is poured into A.
The solution is fed into A through a groove o formed to the vessel. For
applying the varnish coating the cover cm is removed whilst the india rubber
bands or rings v, z remain in position and the wide opening of the shade is then
closed by box H furnished with an inward projecting rim p. is an india rubber
ring for fastening H to shade D.
The shade G is now plunged into the varnish bath and directly removed again
by which operation a coating of varnish is applied to the argentation which will
protect the latter aganst outer influences such as wear and tear and so forth.
Having now described the nature and particulars of the Invention I claim :-
Firstly. The mode of producing single-walled glass reflectors by applying an
argentation to the outer side of the glass-shade and by covering the argentation by
a mineral varnish substantially as heroin described.
Secondly. The combination of apparatus, vats and means for producing the silver
coating as well as the varnish coating to the outer surface of glass-reflectors as
herein described in reference to the accompanying sheet of drawings.
In witness whereof I the said Friedrich Hermann Felix Engel have hereunto
set my hand and seal this sixteenth day of August in the year of our
Lord one thousand eight hundred and eighty-two.