Improvements in Incandescence Bodies for Gas Lighting.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Incandescence Bodies for Gas Lighting.
We, JOHN HENRY HILL DUNCAN, Chartered Accountant, of 39, Coleman Street,
THE NEW INCANDESCENT (SUNLIGHT PATENT) GAS LIGHTING COMPANY, LIMITED,
of 33 and 34, Shoe Lane, both in the City of London, and HARRY THEODORE BAR-
NETT, of 7, Teddington Park Road, Teddington, in the County of Surrey, Engi-
neer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to incandescence bodies for use as light giving
media in non-luminous flanies, and has for objects, inter alia to improve the
colour of the light obtained with such bodies, to produce incandescence bodies
having various light giving properties without departing from the more satis-
factory proportionate combinations of refractory substances to obtain incan-
descence bodies varying within wide limits as to the colour or tint of light result-
ing from their use, and in soñie cases to give additional strength and coherence
to the incandescence bodies.
Most incandescence bodies of high efficiency as now prepared emit light other
than white.e., a light possessing a preponderance of some one or more of the
primary colours, as for instance is the case with the green tinted light emitting
Welsbach mantles and the orange tinted light emitting mantles of the chrome
class.
According to this invention variously tinted light emitting bodies aro
united or combined mechanically in one composite body in such a manner that
the selectively emitted varying colours or tints of light combine to produce an
effect more pleasing to the eye, or better suited to the purpose in view. To this
end we spin, double, knit, plait, cable, interweave, overweave or otherwise
mechanically connect or associate separate filaments, threads, cords, rods or other
shaped bodies containing or consisting of two or more different proportionate
combinations of incandescence oxides which yield lights of differing colour or
tint.
By varying the number or size of filaments of each compound used to form one
thread, or the number of threads, cords or rods of each employed to
construct one composite body-it may be a mantle-or the positions of such
differently-constituted members of such a thread, cord, cable or other body
respectively in relation to the position most favourable for radiating light or for
becoming heated to a maximum temperature, we are enabled to produce incan-
descence bodies whose colour or tint of light varies within comparatively wide
limits as aforesaid without departing from the more satisfactory combinations of
incandescence substances.
For ordinary purposes we sometimes prefer to combine filaments, threads or
other shaped bodies of ceria excited compounds or.the like with filaments, threads
or other shaped bodies of chrome compounds, in order that the approximately com-
plementarily coloured lights given by these different substances may unite to
"

page_text: produce an illumination of more pleasant colour than would be obtainable from
either one of them alone.
The threads, filaments, cords or other shaped bodies of refractory oxide bearing
material or of refractory oxide to be united according to this invention may be
formed by the Welsbach or Knofler processes or otherwise.
One or other of the kinds of filaments, threads or other shaped refractory bodies
constituting a composite incandescence body according to our invention may be
stronger than the remainder and so render the whole mantle more durable, or by
reason of the said strength may allow a weaker substance-perhaps of higher
light emissivity or possessing some other advantage,-to be used in connection
with it.
In some cases we adopt this compound construction of an incandescence body
whereby it contains portions of different constitution, without particular reference
to the colour of light emitted, for the reasons last above stated.
We, JOHN HENRY HILL DUNCAN, Chartered Accountant, of 39, Coleman Street,
THE NEW INCANDESCENT (SUNLIGHT PATENT) GAS LIGHTING COMPANY, LIMITED,
of 33 and 34, Shoe Lane, both in the City of London, and HARRY THEODORE BAR-
NETT, of 7, Teddington Park Road, Teddington, in the County of Surrey, Engi-
neer, 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:―
This invention has reference to incandescence bodies for use as light giving
media in non-luminous flames, and has for objects, inter alia to improve the
colour of the light obtained with such bodies to produce incandescence bodies
having various light giving properties without departing from the more satis-
factory proportionate combinations of refractory substances ordinarily used in
producing incandescence bodies, to obtain incandescence bodies varying within
certain limits as to the colour or tint of light resulting from their use, and in
some cases to give additional strength durability, and coherence to the incan-
descence bodies.
Most incandescence bodies of high efficiency as now prepared emit light other
than white i.e., a light possessing a preponderance of some one or more of the
primary colours, as for instance the green tinted light emitting Welsbach man-
tles and the orange tinted light emitting mantles of the chrome class.
According to this invention such variously tinted light emitting bodies are
united or combined mechanically in one composite body in such a manner that
the selectively emitted varying colours or tints of light combine to produce an
effect more pleasing to the eye, or better suited to the purpose in view than here-
tofore. To this end we spin, double i.e., twist, knit, plait, cable, interweave,
overweave or otherwise mechanically connect or associate separate filaments,
threads, cords, rods or other shaped bodies containing or consisting of different
incandescence oxides which yield lights of differing colour or tint, into one com-
posite structure.

page_text: By varying the number or size of filaments of each compound used to form one
thread, or the number of threads, cords or rods of each compound employed to
construct one composite body-it may be a mantle or the positions of such
differently constituted members of such thread, cord, cable or other body
respectively in relation to the position most favourable for radiating light or for
becoming heated to a maximum temperature, we are enabled to produce incan-
descence bodies whose colour or tint of light varies within comparatively wide
limits as aforesaid without departing from the more satisfactory combinations of
incandescence substances.
For ordinary purposes we sometimes prefer to combine filaments, threads or
other shaped bodies of ceria excited compounds or the like with filaments, threads
or other shaped bodies of chrome compounds, in order that the approximately com-
plementarily coloured lights given by these different substances may unite to
produce an illumination of more pleasant colour than would be obtainable from
either one of them alone.
The threads, filaments, cords or other shaped bodies of refractory oxide bearing
material or of refractory oxide to be united according to this invention may be
formed by the Welsbach or Knofler processes or otherwise.
One or other of the kinds of filaments, threads or other shaped refractory bodies
constituting a composite incandescence body according to this invention may be
stronger than the remainder and so render the whole mantle more durable, or by
reason of the said strength may allow a weaker substance-perhaps of higher
light emissivity or possessing some other advantage, -to be used in connection
with it.
In some cases we adopt this compound construction of an incandescence body,
whereby it contains portions of different constitution, without particular reference
to the colour of light, emitted, for the reasons last above stated.
Incandescence mantles for use with gas flames can be made according to this
invention in various ways. The following are examples of mantles giving a
golden white light.
(1) Two lengths of cotton thread are soaked each in different solutions, one
solution being such as to yield an incandescence body giving a light of greenish
tint, for example the well known mixture or compound of about 99 per cent. thoria
and 1 per cent ceria, and the other solution being such as yields an incandescence
body containing 50 per cent. thoria, 40 per cent. alumina, and 10 per cent. chromic
oxide. The soaked threads are dried and knitted, woven, plaited or otherwise
intertwisted to form a mantle. The two threads may be knitted in such a manner
that the mantle is composed of alternate rows of thoria-ceria and thoria-alumina-
chrome threads, or two or more rows of either kind of thread may be used to one
of the other.
Another mode of making such mantles is to knit the fabric into a continuous
length, composed of alternately arranged short sections of the different kinds of
thread so that mantle lengths may be cut therefrom whose upper and lower por-
tions are of different constitution. Mantles made by a weaving process may have
the different kinds of threads equally distributed in the fabric, or one kind of
thread may be chiefly at the inner surface of the mantle while the other kind is
on the exterior surface of the mantle.
(2) Filaments containing two different mixtures of incandescence oxides are
separately produced by the well known Knofler or some similar process, and the
two kinds of filaments being doubled--i.e., twisted-together to form a com-
posite thread which is made into mantles in the usual way. One kind of filament
may contain thoria and ceria in or about the usual proportions, and the other
kind alumina chromic oxide and zirconia or thoria, a satisfactory prescription
for the latter being thoria 35%, chromic oxide 5% and alumina 60%, the
alumina and thoria being conveniently added to the Knofler collodion in the form
of nitrates of aluminium and thorium, and the chromic oxide as. chromic acid;

page_text: and the two kinds of filaments being used in the proportion of twelve thoria-ceria
filaments to three of the other kind.
J
Incandescence, mantles made according to the foregoing examples give a light
of golden white colour which does not become green in tint even when the mantles
are well worn.
'
It will be obvious that more than two kinds of threads or filaments may be used
and that different kinds of impregnated threads might be doubled together to
form one larger thread from which mantles can be made in the same way as from
the composite Knofler thread, and also that hnofler filaments of differing kind
or composition need not necessarily be united into one thread but might be made
into two or more different threads which can be made into mantles in the manner
herein before described for the impregnated threads.
The burnt off alumina containing threads or filaments being stronger than the
thoria-ceria threads.or filaments their use tends to strengthen the mantle, or that
part of the mantle where they exist.
If it is desired to secure this strengthening effect without appreciably modi-
fying the colour of the light furnished by the thoria-ceria threads or filaments,
the chromic oxide may be omitted from the prescription. If desired some other
strengthening oxide or oxides such as zirconia or silica may be used in place of
the alumina.
As herein before stated it is sometimes advantageous to cable (i.c., to twist an
external covering over a core) two or more kinds of filaments or threads together
to constitute one larger thread and in this case one kind of thread or filament may
constitute the core while another kind constitutes the lapping or covering. When
the core of the cabled thread is of material which contracts more than the lapping
or covering, the effect is to bow or buckle the turns of lapping or covering
material in such a manner that they are more readily permeated and heated by
the flame in which the mantle is placed than would otherwise be the case. Some-
times the core may contain a larger proportion of some constituent than it would
be advisable to employ in threads or filaments which were to be wholly exposed;
a durable thread of this kind may have a core of thoria-ceria in which the ceria
amounts to as much as or more than ten per cent. by weight of the thoria present;
and a lapping or covering in which the thoria contains little or no ceria.
It is to be understood that we are aware that it has heretofore been proposed
to strengthen mantles by the addition to the mantle body of supplementary
threads or metallic wires applied to certain portions thereof but such threads or
wires are local only in action and owing to the variable contraction that takes
place between the mantle bodies and the supplementary threads or wires, the
latter tend to disintegrate the mantle bodies rather than to strengthen them.
In incandescence bodies according to this invention the differently constituted
threads, filaments or the like are united together in the process of manufacturing
such bodies as herein before described, whereby a more equally distributed
strengthening effect can be obtained without tending to disruption by reason of
unequal contraction taking place between the different kinds of threads, filaments
or the like constituting the incandescence body.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is; —
1. An incandescence body for gas lighting made from two or more different
kinds of filaments, threads, cords, rods or other shaped bodies, spun, doubled,
knitted, plaited, cabled, interwoven, overwoven or otherwise mechanically con-
nected together substantially as herein before described for the purposes set forth.
2. An incandescence mantle made from two or more kinds of filaments or
threads containing different incandescing materials, substantially as herein
described for the purposes set forth.
3. An incandescence mantle for gas lighting made from two or more different

page_text: kinds of threads or filaments united together substantially as herein described
for the purposes set forth.
4. An incandescence mantle made of thread doubled or cabled from filaments
or threads containing different incandescence oxides, substantially as described.
5. Incandescence mantles of the composite character herein set forth mado
substantially as hereinbefore described with reference to the several examples
specified.
Dated this 1st day of January 1900.
For the Applicants,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.