Improvements in the Manufacture of Incandescent Tissue for Lamps.
Year: 1895

page_text: Date of Application, 6th July. 1895-Accepted, 10th Aug., 1895
:
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Incandescent Tissue for
Lamps.
I, SAMUEL HENRY CROCKER of 31, Furnival Street, London, Engineer, do
hereby declare the nature of this invention, and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
My invention relates to improvements in the manufacture of incandescent mantles
for lamps, and is designed to provide a form of mantle which shall be easier to
manufacture and more durable and reliable than such mantles as heretofore
produced.
In the manufacture of incandescent mantles as usually practised, considerable
difficulty and waste is experienced in the burning operation owing to the shrinkage
and distortion which take place and which frequently render the mantles unfit for
use when finished.*
Now an important feature of my invention consists in overcoming this difficulty
by employing a wire support for the mantle before burning, formed of a metal
which during the burning operation will be converted into refractory oxide whilst
retaining its original shape. I find that iron wire is very suitable for this purpose
and that during the burning it forms, or becomes converted into a skeleton or frame
of refractory ferric oxide without suffering any appreciable change of shape, and
this ferric oxide frame is not affected by the flame of the lamp to which the mantle-
may be applied nor is it in any way detrimental to the luminous properties of the
said mantle, but rather enhances the same, whilst serving as mechanical support.
for the incandescent materials or compounds:
A further important feature of my invention consists in building up the mantle
by cementing the material thereof to the wire frame or support by means of a
suitable cement such as hereinafter described, whereby I am enabled to construct a
mantle of numerous small strips threads or pieces distinct and separate from each
other, and presenting a very large number of points and edges, which as is well
known are more efficient for illuminating purposes than are plain uniform
surfaces.
I may however, if desired, form the mantle of a single sheet of material,.
perforated or otherwise and having its edges cemented together, or the mantle may
be built up of a few comparatively large pieces instead of a large number of small
pieces.
In making an incandescent mantle according to my invention I prefer to proceed
as follows:
I first construct a truncated conical frame or support consisting of an upper and
a lower ring of thin iron wire connected together by straight wires or ribs disposed
at equal distances all round. To these wires or ribs I attach or apply by means of
cement or otherwise, short strips or pieces of the material from which the
illuminating portion of the mantle is to be formed, these strips being arranged one
above the other regularly from the bottom to the top of each rib and at right angles
or transversely thereto, the strips of one rib being so disposed that they come
opposite the spaces between those of the adjacent ribs, and the finished mantle
having a polygonal form the strips of each rib forming one side of the polygon.
The mantle thus built up is then subjected to the burning operation, the heat being

page_text: -applied somewhat gradually at first and free access of air being allowed in order
that the iron wires of the frame may become thoroughly converted into ferric oxide
before the full heat is applied and may thus retain their shape and serve to support
the refractory illuminating material left by the burning of the strips cemented
thereto.
Obviously the shape to be given to the frame and the mantle will depend upon
the kind of flame to which it is to be applied. The truncated conical form above
described being applicable more particularly to round flames of the kind to which
.mantles are usually applied.
The cement I employ for cementing the strips to the wire frame, or to each other
may consist of any adhesive substance which when burnt will leave a residue capable
of holding together the parts to be connected without injuriously affecting them or
impairing their refractory properties. This substance may be mixed with some or
other of the compounds used for the illuminating portion of the mantle. The
-cement I prefer to employ however, consists of a mixture of dextrin and nitrate of
zirconium brought to a suitable consistency by water to allow it to be conveniently
applied. to the parts to be joined together.
The material I employ for forming the illuminating or incandescent portion of
the mantle consists of a special paper, which during the process of manufacture has
been "loaded" with oxide of zirconium or other refractory "incandescent"
-compound such as employed in incandescent mantles, in place of the kaolin or other
substance generally used for "loading" paper. By this means the incandescent
compound becomes thoroughly incorporated with the substance of the paper, and
the latter can be readily cut into strips or pieces for the purpose of building up my
improved mantles.
I do not however, limit myself to the use of this material as threads or fabrics
saturated with incandescent compounds may be cemented to wire frames in the
manner described.
"
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is.-
(1.) In the manufacture of incandescent mantles for gas lamps the employment of
a frame or support composed of wire which during the burning operation will
become converted into a refractory oxide whilst retaining its original shape and
will serve as a support to the finished mantle substantially as described.
(2.) An incandescent mantle for gas lamps formed by cementing the material
containing the incandescent compounds to a frame composed of iron wire and then
burning the whole so as to convert the iron wire into ferric oxide substantially as
.set forth.
(3.) An incandescent mantle for gas lamps formed of pieces of paper loaded with
incandescent compounds and cemented to a support or frame convertible into a
refractory oxide without material change of shape substantially as described.
(4.) Cementing together materials composed of or containing refractory substances
for the manufacture of incandescent tissue.
.
(5.) A cement for use in the manufacture of incandescent tissue containing
refractory material.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.