Improvements in the Production of Incandescent Materials suitable for use in Electric Lighting.
Year: 1898

page_text: Date of Application, 10th Oct., 1898
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PROVISIONAL SPECIFICATION.
Improvements in the Production of Incandescent Materials suitable
for use in Electric Lighting.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby
declare the nature of this invention (which has been communicated to me from
abroad by The Pharmaceutisches Institut Ludwig Wilhelm Gans, of Frankfort-
on-Main, in the Empire of Germany, Manufacturing Chemists,) to be as follows:-
In my Application of the 19th of August 1898 No. 17896 I described a method
for the production of incandescent materials for use in electric lighting which
solves a problem--long attacked in different ways in quite a new manner, viz.
by using the so-called lustrous noble metal preparations for the production of
the foundation of the incandescent body and using for the production of the
lighting-cover the so-called "lustres" that is, organic compounds soluble in
ether, particularly resinous acid compounds of the metallic oxides.
In the course of my experiments I have discovered a far simpler process for
making the foundation of lustrous noble metal than the somewhat complicated
process which consisted in laying the lustrous noble metal preparation upon
glass or porcelain, burning it in and then etching away the glass or porcelain
ground by acids.
According to this new process I obtain sheets of the noble metals by first
forming a lustre-coating on glass, porcelain or metal, by laying the preparation
of metallic oxide lustre upon the sheet of glass or the like and burning it in;
on this coating a second coating of lustrous noble metal is laid and fixed by
burning in after this the skin of the noble metal is covered by painting it with
collodion solution which forms a thin collodion skin and finally the lustre coating
is removed by being dipped into acid; consequently one obtains the noble-metal
coating in the form of a thin sheet coherent with the collodion cover.
In order to produce the foundation of the electric incandescent body by this
process the highly infusible metals of the platinum group, viz.: osmium, iridium,
rhodium, etc., or suitable alloys of the same are employed. The lustrous prepara-
tions of these metals can be produced in an analogous way to lustrous platinum.
After having first created the lustre cover on glass, porcelain, or metal, the
preparation of lustrous metal is laid on it. The solution of the preparation
may for example be painted with a brush in the shape of a narrow strip or
ribbon, so that after burning in and etching the lustre ground away, the founda-
tion of the incandescent body is obtained directly in the shape desired for use.
If the strip be reinforced by repeated covering and burning in or by the
galvanic process, no collodion skin is required before etching the ground away
as the reinforced strip can easily be removed if carefully treated, without being
torn to pieces.
It is however always desirable for safety's sake, to apply the collodion or
gutta percha cover.
A more convenient way than this of making the foundation direct as a strip

page_text: or ribbon is to produce as a broad sheet and then form it into a wire or thread
by rolling it up.
It is evident that to obtain the thread in the desired shape, length and gauge,
it is only necessary to produce the corresponding design with the solution of
lustrous metal preparation; thus, it is desirable to gradually thicken the thread
at both ends, where it will be connected with the terminals by being pinched
or soldered to them.
The foundation may also be formed into a thin tube instead of a thread by
rolling the skin of lustrous metal up over a cord of cotton, wool or hemp or
over a wooden rod and afterwards removing this centre by burning it away
together with the collodion.
Another method is to make the layer of lustrous metal preparation like net
or lattice-work and burn it in.
By rolling up the detached reticular sheet over a wooden centre a tube of
net-work is obtained to the meshes of which the illuminating earth to be
impasted later on adheres particularly well.
In all these cases one does well to leave the collodion or gutta percha skin
in connection with the sheet metal, until the foundation of the incandescent
body has been formed to the desired shape.
After this it is removed, either by mechanical or chemical dissolving or by
burning.
The coating of the foundation with luminous earth is done in the manner
described in my former application.
The temperature to which the electric incandescent bodies are heated by the
current, being far higher than that reached by Auer's gas-incandescent light,
even those kinds of carths such as chalk, or magnesia of which the power of
light-emission is still trifling at the temperature of Auer-light, but increases
considerably at a higher temperature, can be employed.
Dated this 10th day of October 1898.
Improvements in the Production of Incandescent Materials suitable
for use in Electric Lighting.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby
declare the nature of this invention (which has been communicated to me from
abroad by The Pharmaceutisches Institut Ludwig Wilhelm Gans, of Frankfort-
on-Main, in the Empire of Germany, Manufacturing Chemists,) and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:―
In the Application of the 19th of August 1898 No. 17896 is described a
method for the production of incandescent materials for use in electric lighting,
which solves a problem-long attacked in different ways—in quite a new manner,
viz. in using the so-called lustrous preparations of the noble metals for the
production of the core (centre or inside) of the incandescent body and in using
for the production of the coating, consisting of oxides of the luminous earthy
metals, the lustrous preparations of the baser (non-precious) metals.
The lustres or lustrous preparations of the metals, hitherto sold and used for
the decoration of porcelain, glass etc., are organic compounds of metals (resin
acid compounds, or sulphuretted, resin compounds, or products of the decom-
position of metallic chlorides, produced by heating them with lavender oil),

page_text: mixed in their application with an ethereal oil, such as lavender oil. Such
lustrous preparations of many metals are known, but there is a very remarkable
difference between those, which have for basis the so-called noble metals, i.c.
gold, silver and all the metals of the platinum group, and those which have for
basis the baser ("non precious") metals. The first ones, when applied upon
porcelain, glass or metal and then heated to a high temperature, leave behind
a thin skin of metal, whilst the lustres of the baser metals, when treated in
the same manner, form a skin of metallic oxide.
The process described in the above mentioned Application No. 17896/98 consists
in covering a plate or matrix of porcelain, glass etc. with a lustrous preparation
of one or more of the highly infusible metals of the platinum group, burning
the same in, detaching the resultant metallic film from the plate or matrix (the
bed," as it is called,) by the action of solvents, which will attack the bed and
not the film, forming the said metallic film into the desired shape and coating
the said so-formed metallic film with the lustrous preparation of one or more
of the luminous earthy metals and burning the same in.
This way of making the core or interior of my incandescent materials not
being very agreeable in working for several reasons, a second way which is
much more suitable has been discovered by my correspondents.
This new
process is not only adapted for producing the core of the incandescents, but
serves also for the manufacture of metal foil or leaf which hitherto could only
be obtained by hammering. In the Application No. 21306/8 I have explicitly
described this method of producing metal foil or leaf and here I will repeat the
principal points of the process.
A solution of a ceramic lustre of baser ("non precious") metals-for example
the resin oxid compound of it mixed with an ethereal oil-is spread upon the
surface of a plate or matrix of porcelain, glass, metal or other material, which
is not or not much attacked by diluted acids and capable of enduring unimpaired
the temperature necessary to burn in the lustre employed; the lustre may be
replaced by fluxes easily soluble in acids, such as borosilicates or phosphates of
soda or the like; then the lustre or its substitute is burned in. Upon this bed,
as it may be called, a lustrous preparation of the desired noble metal is laid
and burned in the usual manner; this may be repeated again until the desired
thickness is attained, or it may be thickened by electrolytic deposition of the
metal. Then the skin of the noble metal is detached by immersing the plate
in a solvent of the bed (principally inorganic and strong organic acids), which is
thus dissolved away, leaving the skin of the noble metal free. But these skins
of the noble metal, particularly if very thin, are easily torn. To avoid such
accidents it is advisable to brush over the skin of noble metal with some form
of tough varnish, such as collodion or a guttapercha solution after firing and
before endeavouring to detach the skin from the plate. This protecting coating
can be dissolved away by any suitable solvent as soon as the metal skin is removed
from the plate or it may be allowed to remain indefinitely to protect the metal
skin until its removal becomes desirable.
The application of this new process for the production of electric incandescent
bodies is easily to be comprehended:
One employs the highly infusible metals of the platinum group, viz.: osmium,
iridium, rhodium and rhuthenium or suitable alloys of same. The lustrous
preparations of these metals can be produced by analogy with lustrous platinum.
After having first created the cover of oxide of a baser metal upon the bed,
as described above, the lustrous preparation of the highly infusible metal of the
platinum group, for example osmium, is laid upon this couch in a suitable
manner. The solution of the preparation may, for instance, he painted with a
brush in the shape of a narrow strip or ribbon, so that after burning in and
etching the "bed" away, the core of the incandescent body is obtained directly
in the shape desired for use.
If one reinforces the strip by repeated covering and burning in or by the

page_text: galvanic process, no collodion skin is required at all before etching the ground
away, as the reinforced strip can easily be removed, if carefully treated, without
being torn to pieces, but it is preferable, for safety's sake, to apply in all cases
the collodion or guttapercha cover.
.
Instead of laying the lustrous preparation of the highly infusible metal upon
the bed directly in the shape, which is desired for the core of the incandescent
body, it may also be worked in other manners, for instance, the foil or leaf of
any shape, still covered with the protecting varnish, if such varnish is used,
is formed into a thin rod or thread by rolling it upon itself, or into a tube by
rolling it around a thread or strong, or in any other suitable manner. The said
rod or thread or tube is then formed into the desired shape, and the collodion
or varnish and the thread or string core, if any, is burned or dissolved away.
As shown in the Application No. 21306/8 metal foil or leaf may by its method
be produced in the form of a leaf or in the form of any pattern. So the core
of my incandescent body can, in accordance with that invention, be given any
desired form; for example, that of a net work by laying the lustre upon its
"bed" in a reticulated pattern, burning it in, and then forming it into a mantle
like those used in gas incandescent lighting; or such a reticulated mantle, or
indeed almost any form, can be produced by giving the desired form to the
porcelain or its substitute, to which the lustres are applied before the first firing.
In all these cases one does well to leave the collodion or guttapercha skin in
connection with the metal foil, until the core of the incandescent body has been
formed to the desired shape.
After this it is removed, either by dissolving or by glowing.
The coating of the core with luminous carth is done in the manner described
in the repeatedly mentioned Application No. 17896 of August 19th 1898.
As will be easily perceived from the above description, the new process repre-
sents an important advance upon the former method described in the Application
No. 17896 consisting in two essential improvements.
upon a
1) In making use of the oxide-lustres of the baser metals, applying them
bed" as basis for the lustres of the metals of the platinum group.
2) In applying a collodion cover in order to protect the skins of noble metals,
before dissolving the same.
The second improvement (collodion-skin) applied to the process described in
the Application No. 17896 represents in itself a great advantage.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed I declare that what
I claim is
1. The herein described process of manufacturing bodies suitable for incan-
descent electric lighting, which consists: first, in wholly or partially covering
a plate or matrix of glass, porcelain, earthenware or the like with a lustrous
preparation of one or more of the highly infusible metals of the platinum group
and burning the same in; second, covering the metallic film so produced with
a tough protective varnish; third, detaching the resultant metallic film from
the bed by the action of solvents which will attack the bed and not the film; and
fourth, forming the said metallic film into the desired shape.
2. The herein described process of manufacturing bodies suitable for incan-
descent electric lighting, which consists: first, in wholly or partially covering
a plate or matrix of glass, porcelain, earthenware or the like with a lustrous
preparation of one or more of the highly infusible metals of the platinum group
and burning the same in second, covering the metallic film so produced with
a tough protective varnish; third, detaching the resultant film from the bed
by the action of solvents which will attack the bed and not the film: fourth,
forming the said metallic film into the desired shape: fifth, removing the tough
protective varnish from the metallic film by means of a solvent or by burning,
using either fire or the electric current, and sixth, coating the metallic film with

page_text: ceramic resin lustre of one or more of the luminous earthy metals and burning
the same in.
3. The herein described process of manufacturing bodies suitable for incan-
descent electric lighting, which consists: first, in wholly or partially covering
a plate or matrix of glass, porcelain, earthenware, or metal, which is not or not
much attacked by diluted acids with a ceramic lustrous preparation of one or
more of the non precious metals and burning the same in; second, laying upon
this coating of non precious metallic oxide a lustrous preparation of one or more
of the highly infusible metals of the platinum group and burning it in; third,
detaching the resultant film of the said highly infusible metal by the action of
a solvent which will attack the non precious metallic oxide but not the highly
metal into the desired shape.
4. The herein described process of manufacturing bodies suitable for incan-
descent electric lighting which consists: first, in wholly or partially covering
a plate or matrix of glass, porcelain, earthenware or metal, which is not or not
much attacked by diluted acids with a ceramic lustrous preparation of one or
more of the non precious metals and burning the same in; second, laying upon
this coating of non-precious metallic oxide a lustrous preparation of one or more
of the highly infusible metals of the platinum group and burning it in; third,
covering the metallic film so produced with a tough protective varnish; fourth,
detaching the resultant film of the said highly infusible metal by the action of
a solvent which will attack the non precious metallic oxide but not the highly
infusible metal film, and lastly, forming the detached film of the highly infusible
metal into the desired shape.
5. The herein described process of manufacturing bodies suitable for incan-
descent electric lighting, which consists; first, in wholly or partially covering
a plate or matrix of glass, porcelain, earthenware or metal, which is not or not
much attacked by diluted acids, with a ceramic lustrous preparation of one or
more of the precious metals and burning the same in; second, laying upon
this coating of non precious metallic oxide a lustrous preparation of one or
more of the highly infusible metals of the platinum group and burning it in;
third, detaching the resultant film of the said highly infusible metal by the
action of a solvent which will attack the non precious metallic oxide, but not
the highly infusible metal film; fourth, forming the detached film of the highly
infusible metal into the desired shape; and lastly, coating said so formed
metallic film with ceramic resin lustre of one or more of the luminous earthy
metals and burning the same in.
6. The herein described process of manufacturing bodies suitable for incan-
descent electric lighting, which consists; first, in wholly or partially covering
a plate or matrix of glass, porcelain, earthenware or metal, which is not or
not much attacked by diluted acids with a ceramic lustrous preparation of one
or more of the non-precious metals and burning the same in; second, laying
upon this coating of non precious metallic oxide a lustrous preparation of one
or more of the highly infusible metals of the platinum group and burning it in ;
third, covering the metallic film so produced with a tough protective varnish:
fourth, detaching the resultant film of the said highly infusible metal by the
action of a solvent, which will attack the non precious metallic oxide, but not
the highly infusible metal film; fifth, forming the said metallic film into the
desired shape sixth, removing the tough protective varnish from the metallic
film by means of a solvent or by burning, using either fire or the electric current;
and seventh, coating the metallic film with ceramic resin lustre of one or more
of the luminous earthy metals and burning the same in.