Improvements in Incandescent Gas Burners.
Year: 1897

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c. Act, 1883) as required by
the decision of the Chief Examiner of the 28th day of November 1898.
Improvements in Incandescent Gas Burners.
I, OTTMAR KERN, of 9, Avenue de l'Opéra, Paris, France, Engineer, do hereby
declare the nature of this invention to be as follows:-
My invention has reference to improvements in incandescent gas burners of the
kind which criginally became known as the Clamond incandescent gas burners, and
which later have been variously improved by numerous inventors, and particularly by
Auer von Welsbach; and the object of the invention is to produce a burner that
shall raise the refractory mantle or hood to a higher degree of incandescence than
has heretofore been accomplished with the same amount of illuminating gas, and at
the ordinary pressures at which gas is ordinarily delivered; and this without the use
of an artificial draft, such as is ordinarily produced by glass chimneys, and sometimes
by mechanical blowers.
This object I realise by constructing a burner in which the admission of air to the
gas is so adjusted that, in the mixture obtained, the amounts of oxygen and hydro-
carbon gas are, practically, in the proportion of the chemical equivalents of these
two gases; thereby the mixture becomes self burning, that is to say, it will burn in a
closed chamber from which the external air is excluded. This self burning mixture
is, by my improved burner, caused to issue from the burner tip under greater pressure
than with an ordinary Bunsen burner of the gas distributing system, and with greater
speed than that with which the flame can propagate itself through the mixture;
whereby the flame is prevented from burning backwards, and is thus steadily main-
tained above the exit opening of the burner tip. Within the flame of such self
burning mixture, there is a zone of superior incandescence, which zone I call the
hyper-incandescent zone, and which is very much hotter than the rest of the flame.
My burner is so arranged that the refractory filament, or mantle of filaments, is
exceedingly close to or immersed in this hyperincandescent zone, whereby the fila-
ment, or mantle of filaments also becomes hyperincandescent, and thus furnishes,
with the same consumption of gas a more intense light, or the same amount of light,
with a less consumption of gas.
According to one construction the burner is of the Bunsen type, but modified in
accordance with any invention, in one particular respect. There is the ordinary gas
inlet with its nozzle, screwed into the Bunsen pipe, as usual. The pipe has the
customary air ports, and throttle ring, whereby the admission of air can be regulated
at will. The distinguishing feature of this pipe is that it is formed to present two
cone frusta, joined at their smaller bases, the lower cone frustumn being shorter than
the upper.
A pipe or tube of this general construction, but with its parts differently
proportioned, has become noted in hydraulics as Venturi's pipe; it is sometimes used

page_text: as a nozzle through which water or other fluids are discharged, and when so used
increases the amount of the discharge.
I have found that when this double-cone pipe is used in a Bunsen burner, it
operates to increase the quantity of air forced through the pipe; produces a more
thorough mixture of the air and gas, and at the same time delivers the mixture at a
much higher pressure than the ordinary Bunsen burner does. The lower cone frustum
I call the mixing cone, since within the same the air and gas are primarily mixed;
the upper cone I call the suction cone, since its function is to accelerate the issue of
the mixture at a narrow section.
I have found that the best results are obtained when the angle of divergence of
the suction cone is between 5° and 7°. When the angle of divergence is increased
beyond 70, the suction diminishes, and almost disappears when the angle becomes
greater than 10°.
The angle of divergence of the mixing cone may be varied between wider limits,
but I have found it best not to make this angle larger than 10°. The length of the
mixing cone must be such as to permit the air and gas to be well mixed before
the mixture reaches the narrow section, and this length of the mixing cone is deter
mined experimentally in the following manner :-
Over a jet of gas, issuing vertically upwards from a nozzle, I arrange a wire gauze
horizontally, and so that its distance from the nozzle opening can be adjusted. I
then light the mixture of air and gas above the gauze, and by the appearance of
the flame it is noticed that the quality of the mixture varies with the distance of
the gauze from the nozzle. This distance is then adjusted until the flame shows the
characteristic of a self burning mixture, as herein before explained, and which will be
dwelt upon more in detail further on. The proper distance, thus determined, is then,
used as the measure of the length of the mixing cone.
I have found that the suction cone, in order to obtain the best results, should be
about twice as long as the mixing cone; in practice, however, it is not necessary to
make it quite so long, since it may be considerably shorter and still produce sufficient
suction for the purposes of my improved burner. But while the length of the suction
cone may be varied considerably, without appreciably affecting the suction effect, the
same thing is not true of the angle of divergence of that cone, since, as above stated,
this angle should be in order to obtain the best effect, between the limits of 5° and 7º,
and should never exceed 10°.
As an illustration of the dimensions of a burner, constructed upon these principles;
let us assume that the burner is to consume 80 litres of gas per hour. In that case
the narrow section of the pipe, should be 7 millimetres; the length of the mixing
cone, 3 centimetres, and the length of the suction cone 6 centimetres. Now, the.
length of the suction cone might be reduced to 5 centimetres, and might be made
even shorter, and still have sufficient suction effect. The angle of divergence of the
suction pipe, however, should always be within the limits of 5° and 7°, since any
reduction of this angle below 5° or any increase of the same above 7°, reduces the
suction effect very considerably. It is, therefore, not sufficient that the Bunsen tube
be shaped so that its bore defines two truncated cones, joined at their small bases,
since this general construction would be altogether useless for the purposes of my
invention, unless the proportion of dimensions above indicated be carefully
observed.
If a Bunsen tube is constructed as thus far described, and without the nozzle at
the upper end of the suction cone and the gas mixture, issuing from the flaring
opening of the suction pipe, is ignited, it will not maintain a flame at and above the
opening, since the velocity of the gas under ordinary pressure is not sufficient to
prevent it from burning back, downwardly into the tube. In order to prevent this,
the nozzle by which the exit opening is reduced, is applied, and with a burner thus
constituted the flame will be maintained at and above the nozzle.
Owing to the fact that the air and gas are forced together through the narrow
section of the pipe from the mixing cone into the suction cone, a tolerable intimate
mixture is obtained; but in order to still more intimately mix the air and gas, 'a
'

page_text: construction is employed, in which the upper end of the suction cone is formed with
a flange having two concentric grooves. Into the inner groove is fitted the lower
edge of a hollow perforated cylinder, the upper end of which is solid. The
perforations of the cylinder are preferably conical, flaring inwardly, and while these
perforations are very small, the aggregate of their cross sections must be large
enough to offer no appreciable resistance to the passage of the gas mixture.
Into the outer groove in the said flange, is fitted a hollow cylinder, which together
with the perforated cylinder constitutes a mixing chamber. The outer cylinder is
surmounted by a cap which terminates in a nozzle. The gas mixture, issuing from
the suction cone passes through the perforations of the perforated cylinder, whereby
the mixture is made more perfect, and then issues by the nozzle.
An investigation of the flame, under various adjustments of the throttle-ring,
shows the following results :-
When the throttle-ring is turned so as to close the air admission ports at the¯
bottom of the double cone tube completely, the flame produced has the shape and
characteristic of the flame of an ordinary Bunsen burner when the air ports of the
same are closed; but when now the air ports are gradually opened, more and more,
in three successive steps, the appearances of the flame become modified as
follows:-
1st. With a slight admission of air, the flame is long, blue in colour, with a
central cone of a darker blue.
2. By increasing the admission of air, the size of the flame is diminished; the
central cone assumes a greenish hue, and is surrounded by a blue envelope.
3rd. When the port holes are entirely opened, the flame becomes much
reduced in size; the central cone becomes quite small, loses its greenish colour,
and appears to be enveloped by a violently agitated zone of a whitish hue.
The peculiar properties of the flames, thus produced may be investigated in a
variety of ways. Assuming a chamber to be closely fitted over the burner tip
with an opening at top for the escape of the gas mixture; then if only a small
or a moderate quantity of air is mixed with the gas, the mixture will not burn
at the opening of the chamber until after air from the surrounding atmosphere
has been added to the mixture. But, when the gas mixture is such as was last
above mentioned and is ignited at the opening, the flame will immediately jump
back, and burn at the nozzle within the chainber, although a small flame may still
remain at the mouth of the opening of the latter. This proves that the mixture
produced, when the ports of my improved burner are wide open, or properly
adjusted, is a self burning mixture, and this is the kind of mixture of air and gas,
which must be produced in my improved burner, in order to accomplish the results
aimed at.
The small flaine which still remains at the opening, is due to a small portion of
gas which is not burned at the inner nozzle and this indicates that the mixture is
not absolutely self-burning, that is to say, that there is not, yet sufficient air mixed
with the gas. Now, by the admixture of additional quantities of air, the small flame
at the opening, may be reduced to a minimum; thus showing that the mixture is
more and more approaching that condition in which it is absolutely self burning.
It will now be understood that for different qualities of lighting gas, and for
different pressures, the air ports must be adjusted differently, in order to produce a
self burning mixture; and the above described burner with the addition of the top
chamber is a convenient means for determining, in each case, the required adjust-
ment of the throttle ring.
The heating capacities of the different portions of the flames produced by the
above described different adjustments of the throttle ring can be examined by the
introduction into the flames of refractory filaments.
In the case of the first described flame, having a small admission of air, it is found
that the filament reaches the highest degree of incandescence when it is placed
within the outer part and near the outer surface of the flame, and not when it is
immersed into the interior of the flame. This shows that the most perfect combus-

page_text: tion occurs where the gas mixture comes in contact with the surrounding atmosphere,
from which it receives additional oxygen, while the combustion within the flame is
comparatively very imperfect.
"
With the second above described flame, having an increased admission of air, it
is found that the filament is raised to the same degree of incandescence in all parts
of the flame from which it must be concluded that the degree of combustion is the
same all throughout.
;
If now the flame produced by the self burning mixture, i.e. with the full supply of
air, is explored with a refractory thread, it is found that it is raised to an exceedingly
high degree of incandescence in the hyperincandescent zone while in all other parts
of the flame the incandescence of the thread is comparatively low.
These observations conclusively show that the highest degree of incandescence of
a refractory mantle, would he obtained by exposing it to the heating effect of the
hyperincandescent zone of a self burning mixture of air and gas, and it will presently
be shown how this is accomplished.
Suppose a burner, such as described, with an ignited self burning mixture issuing
from the same, be inclined, so as to make the side of the hyperincandescent zone
along one line (the generatrix), vertical; and suppose that a refractory thread also
extending vertically, be adjusted either near to or actually touching or immersed in
the vertical portion of the hyperincandescent zone; then the whole flame will take
such a shape as to cause a considerable portion of the refractory thread to be raised
to hyperincandescence. Supposing now that this whole hypothetical structure be
rotated about a vertical axis, it is evident that the hyperincandescent thread will
trace in space the surface of a cylinder, and if rotated fast enough, the eye of the
observer will be impressed as by a hyperincandescent cylinder.
These considerations led to the following construction of my improved incan-
descent gas burner.
.There is fixed upon the top of the before described perforated cylinder a conical
upward flaring cup,. while upon the cap of the outer cylinder is fitted a short
cylindrical tube; and the dimensions of these two parts are such as to form between
their upper edges an annular nozzle, from which the gas mixture issues in such
direction that, when ignited, the outer surface of the hyperincandescent zone will
be vertical, or nearly so, while the inner surface of that zone will be inclined
outwardly. A mantle of refractory threads, is fitted over the said short cylinder,
and is suspended at its upper end from a copper hook fitted to a looped support,
also of copper, or other good conductor of heat, and which is secured to the exterior
cylinder of the mixing chamber.
A burner thus constructed does not require a draft of air along the surface of the
mantle of refractory threads, since the combustion of the self burning gas mixture is
perfect without resort to such artificial draft. No glass chimney, therefore, need
be employed. The hyperincandescent zone of the flame of the self burning gas
mixture does extend upwardly, but not throughout the whole length of the
mantle; a portion of the length of the mantle therefore only will be raised to
hyperincandescence, while the upper portion of it will be heated less, but still to a
high degree of incandescence, and the effect of the whole will be that of an
extremely highly incandescent body, inuch higher than is obtained by the ordinary
incandescent gas burners.
It is evident that the upper portion of the looped support will be heated
considerably by the ascending jet, and being connected with the external cylinder of
the mixing chamber, it will heat the mixture within the same by conduction, which is
an additional advantage.
Instead of making the burner tip in two separate concentric parts as described
the tip may be stamped out of one sheet of metal, in which case, however, the
flame will not be completely annular, since the gas mixture will issue only by ring
openings divided by the necessary connection of the inner and outer part or by a
number of holes, which may be circularly arranged. In each case, however, whatever
be the shape of the burner tip opening, or openings, the hyperincandescent zone or

page_text: zones of the flame or flames, will have the above described shape, that is to say,
the outer side will be vertical and the inner side inclined outwardly.
For a greater amount of light, a duplex structure of incandescent burner, may be
employed. In this case there are a number of Bunsen pipes, receiving the gas from
a gas chamber, common to all, upon which they are mounted. The upper ends of
these Bunsen pipes are fitted into a metal ring, which thus forms a common flange
for the upper ends of the suction cones of the modified Bunsen pipes. Into four
concentric grooves, formed in the upper surface of the said ring, and enclosing the
orifices of all the Bunsen pipes, is fitted the annular mixing chamber, composed of
two concentric, cyclindrical, perforated diaphragms, and two concentric inner and
outer cylinders, both being capped as shown. In this case the burner tip is
composed of two concentric cylinders, fitted upon the cap of the inner and outer
cylinders, and an annular upward flaring trough, fitted upon the cap of the diaphragm.
In this manner there are, in reality, produced two concentric annular-burner-tip
openings, which would-furnish-two concentric annular flames, each having a
hyperincandescent zone. Upon the short outside cylindrical part of the annular
nozzle, is fitted an upwardly converging mantle and within the inner short cylindrical
part of the nozzle, is fitted the upwardly diverging mantle, of refractory threads;
these two mantles being so arranged as to enclose between them an annular space,
both the outer and inner walls of which are exposed to the heating effect of the
hyperincandescent zone of the concentric flames of the self burning gas mixture.
The mantles inay be mounted upon rings at top suitably suspended by hooks from
horizontal arms, radiating from a central vertical rod which rises from a cross
piece on the annular base of the burner.
.
A number of short radial arms, extending from the vertical rod, are connected
with the inner solid wall of the mixing chamber of the burner. All these connections
are made of good conductors of heat so that the gas in the mixing chamber is
heated, preparatory to its ignition.
It will be understood that the details of construction of my above described
improved incandescent gas burner may be varied in a great number of ways, without
departing from the fundamental principles of my invention.
t
1001
ABEL & IMRAY,
Agents for the Applicant.
I, OTTMAR KERN, of 9, Avenue de l'Opéra, Paris, France, 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 has reference to improvements in incandescent gas burners of the
kind which originally became known as the Clamond incandescent gas burners, and
which later have been variously improved by numerous inventors, and particularly
by Auer von Welsbach; and the object of the invention is to produce a burner that
shall raise the refractory mantle or hood to a higher degree of incandescence than
has heretofore been accomplished with the same amount of illuminating gas, and at
the ordinary pressures at which gas is usually supplied, and this without the use of
an artificial draught, such as is ordinarily produced by glass chimneys, and sometimes
by mechanical blowers.
This object I realize by constructing a burner in which the admission of air to the
gas is so adjusted that, in the mixture obtained, the amounts of oxygen and

page_text: hydrocarbon gas are, practically, in the proportion of the chemical equivalents of
these two gases; thereby the mixture becomes self burning; that is to say, it will
burn in a closed chamber from which the external air is excluded. This self burning
mixture is, by my improved burner, caused to issue from the burner tip under
greater pressure than with an ordinary Bunsen burner of the gas distributing system;
and with greater speed than that with which the flame can propogate itself through
the mixture; whereby the flame is prevented from burning backwards, and is thus
steadily maintained above the exit opening of the burner tip. Within the flame of
such self burning mixture, there is a zone of superior incandescence, which zone I
call the hyperincandescent zone, and which is very much hotter than the rest of the
flame.
My burner is so arranged that the refractory filament, or mantle of filaments, is
exceedingly close to or immersed in this hyperincandescent zone, whereby the
filament, or mantle of filaments also becomes hyperincandescent, and thus furnishes,
with the same consumption of gas, a more intense light, or the same amount of
light, with a less consumption of gas.
All this will more fully appear from the following detailed description, in which
reference is made to the accompanying drawings in which :-
Figure 1, is a longitudinal section of a Bunsen burner, modified in accordance with
my invention;
Figure 2, shows partly in elevation and partly diagrammatically, an experimental
apparatus used for determining one of the dimensions of the improved Bunsen burner;
Figure 3, is a longitudinal section of the improved Bunsen burner, provided with
a gas mixing chamber;
Figure 4, a cross-section of a portion of the same.
Figures 5, 6, 7, 8 and 9, show burner tips and the flames produced by various gas
mixtures.
Figure 10, is a diagram, illustrating, hypothetically, the utilization of the
principles of my invention;
Figure 11, a longitudinal section of a complete incandescent gas burner, constructed
in accordance with my invention.
Figure 12, a central section and plan, respectively, of the burner tip used in the
construction shown in Figure 11, and
Figure 13, is a central section of a duplex incandescent gas burner, constructed in
accordance with my invention.
Like numerals of reference indicate like parts all throughout the drawing.
Referring now particularly to Figure 1, there is shown a burner of the Bunsen
type, but modified in accordance with my invention, in one particular respect. There
is the ordinary gas inlet 1, with its nozzle 2, screwed into the Bunsen pipe 5, as
usual. The pipe has the customary air ports 3, and the throttle ring 4, whereby the
admission of air can be regulated at will. The distinguishing feature of this pipe 5,
is that it is formed to present two cone frusta 6, 7, joined at their smaller ends at 8,
the lower cone frustum being shorter than the upper. A pipe or tube of this general
construction, but with its parts differently proportioned, has become noted in
hydraulics as Venturi's pipe; it is sometimes used as a nozzle through which water
or other fluids are discharged, and when so used increases the amount of the
discharge.
I have found that when this double-cone pipe is used in a Bunsen burner, it
operates to increase the quantity of air forced through the pipe; produces a more
thorough mixture of the air and gas, and at the same time delivers the mixture at a
much higher pressure than the ordinary Bunsen burner does.
The lower cone
frustum 6, I call the mixing cone, since within the same the air and gas are primarily
mixed; the upper cone 7, I call the suction cone, since its function is to accelerate
the issue of the mixture at a narrow section 8.
I have found that the best results are obtained when the angle of divergence of the
suction cone is between 5° and 7°. When the angle of divergence is increased

page_text: beyond 7°, the suction diminishes, and almost disappears when the angle becomes
greater than 10º.
The angle of convergence of the mixing cone may be varied between wider limits,
but I have found it best not to make this angle larger than 10°. The length of the
mixing cone must be such as to permit the air and gas to be well mixed before the
mixture reaches the narrow section 8, and this length of the mixing cone is deter-
mined experimentally in the following manner:
Over a jet of gas, issuing vertically upwards from a nozzle 2, (see Figure 2), I
arrange a horizontal wire gauze 10, so that its distance from the nozzle opening can
be adjusted. I then light the mixture of air and gas above the gauze, and by the
appearance of the flame it is noticed that the quality of the mixture varies with the
distance of the gauze from the nozzle. This distance is then adjusted until
the flame 11, shows the characteristic of a self burning mixture, as hereinbefore
explained, and which will be dwelt upon-more in detail further on.
The proper.
distance, thus determined, is then used as the measure of the length of the mixing
cone 6.
I have found that the suction cone, in order to obtain the best results, should be
about twice as long as the mixing cone; in practice, however, it is not necessary to
make it quite so long, since it may be considerably shorter and still produce sufficient
suction for the purposes of my improved burner. But while the length of the
suction cone may be varied considerably, without appreciably affecting the suction
effect, the same thing is not true of the angle of divergence of that cone, since, as
above stated, this angle should be, in order to obtain the best effect, between the
limits of 5 and 7°, and should never exceed 10°.
As an illustration of the dimensions of a burner, constructed upon these principles,
let us assume that the burner is to consume 80 litres of gas per hour.
In that case.
the narrow section 8, of the pipe 5, should be 7 millimetres; the length of the mixing
cone, 3 centimetres, and the length of the suction cone 6 centimetres. Now, the
length of the suction cone might be reduced to 5 centimetres, and might be made
even shorter, and still have sufficient suction effect. The angle of divergence of the
suction pipe, however, should always be within the limits of 5° and 7°, since any
reduction of this angle below 5° or any increase of the same above 7°, reduces the.
suction effect very considerably. It is, therefore, not sufficient that the Bunsen.tube.
be shaped so that its bore defines two truncated cones, joined at their small ends,
since this general construction would be altogether useless for the purposes of my
invention, unless the proportion of dimensions above indicated be carefully.
observed.
If a Bunsen tube is constructed as thus far described, and without the nozzle 9,
shown in Figure 1, and the gas mixture, issuing from the flaring opening of the
suction pipe, is ignited, it will not maintain a flame at and above the opening, since
the velocity of the gas under ordinary pressure is not sufficient to prevent it from
burning back, downwardly into the tube. In order to prevent this, the nozzle 9, by
which the exit opening is reduced, is applied, and with a burner; thus constituted the
flame will be maintained at and above the nozzle.
Owing to the fact that the air and gas are forced together through the narrow
section 8, of the pipe 5, from the mixing cone into the suction cone, a tolerably
intimate mixture is obtained; but in order to still more intimately mix the air and
gas, the construction shown in Figure 3, is employed. In this case the upper end
of the suction cone 7 is formed with a flange 12, having two concentric grooves, as
shown. Into the inner groove is fitted the lower edge of a hollow perforated.
cylinder 13, the upper end 14 of which is closed. The perforations of the cylinder
are preferably conical, flaring inwardly, as indicated in Figure 4, and while these
perforations are very small, the aggregate of their cross sections must be large
enough to offer no appreciable resistance to the passage of the gas mixture..
Into the outer groove in, the flange 12, is fitted a hollow cylinder 15, which
together with the perforated cylinder 13, constitutes a mixing chamber.
cylinder 15, is surmounted by a cap 16, which terminates in the nozzle 9. The gas:
The

page_text: 1
mixture, issuing from the suction cone 7, passes through the perforations of the
perforated cylinder 13 whereby the mixture is made more perfect, and then issues
by the nozzle 9.
An investigation of the flame, under various adjustments of the throttle-ring, shows
the following results:-
When the throttle-ring is turned so as to close the air admissión ports 3, completely,
the flame produced has the shape and characteristic of the flame of an ordinary
Bunsen burner when the air ports of the same are closed; but when now the air ports
are gradully opened, more and more, in three successive steps, the appearances of the
flame become as indicated in Figures 5, 6 and 7.
First With a slight admission of air, the flame is long, as shown in Figure 5; blue
in colour, with a central cone of a darker blue.
Second By increasing the admission of air, the size of the flame is diminished; the
central cone assumes a greenish hue, and is surrounded by a blue envelope.
Third When the port holes are entirely opened, the flame becomes much reduced
in size; the central cone becomes quite small, loses its greenish colour, and appears
to be enveloped by a violently agitated zone of a whitish hue. This is indicated in
Figure 7, where the white cone is marked by the reference numeral 17.
The peculiar properties of the flames, thus produced, may be investigated in a
variety of ways. In Figures 8 and 9, there is shown a chamber 18, closely fitted over
the burner tip 9, with an opening 19, for the escape of the gas mixture. If the gas
mixture is such as has been discussed with reference to Figures 5 and 6, that is to
say, when only a small or a moderate quantity of air is mixed with the gas, the
mixture will burn at the opening 19, of the chamber 18, as shown in Figure 8; that
is to say, it will not burn until after air from the surrounding atmosphere has been
added to the mixture. But, when the gas mixture is such as has been discussed with
reference to Figure 7, and when the mixture is ignited at the opening 19, the flame
will immediately jump back, and burn at the nozzle 9,. although a sinall flame may
still remain at the mouth of the opening 19. This proves that the mixture produced,
when the ports of my improved burner are wide open, or properly adjusted, is a self
burning mixture, and this is the kind of mixture of air and gas, which
must be produced in my improved burner, in order to accomplish the results
aimed at.
The small flame which still remains at the opening 19, is due to a small portion
of gas which is not burned at the burner tip 9, and this indicates that the
mixture is not absolutely self burning, that is to say, that there is not yet
sufficient air mixed with the gas. Now by the admixture of additional quantities
of air, the small flame at the opening 19, may be reduced to a minimum; thus
showing that the mixture is more and more approaching that condition in which it
is absolutely self burning.
It will now be understood that for different qualities of lighting gas, and for
different pressures, the air ports must be adjusted differently, in order to produce a
self burning mixture; and the burner shown in Figure 3, with the addition of the top
chamber 15, is a convenient means for determining, in each case, the required
adjustment of the throttle-ring.
The heating capacities of the different portions of the flames produced by the
three different adjustments of the throttle-ring, contemplated with reference to
Figures 5, 6 and 7, can be examined by the introduction into the flames of refractory
filaments, as indicated in Figures 5, 6 and 7, where such filaments are shown
at 20.
In the case of the flame indicated in Figure 5, it is found that the filament
reaches the highest degree of incandescence when it is placed within the outer part
and near the outer surface of the flame, as indicated in the drawing, and not when
it is immersed into the interior of the flame. This shows that the most perfect
combustion occurs where the gas mixture comes in contact with the surrounding
atmosphere, from which it receives additional oxygen, while the combustion within
the flame is comparatively very imperfect.

page_text: With such flame as is indicated in Figure 6, it is found that the filament is raised
to the same degree of incandescence in all parts of the flame; from which it must
be concluded that the degree of combustion is the same all throughout. When
comparing the degree of incandescence of the filament 20, which just touches the
outer surface of the flame, shown in Figure 5, with the degree of incandescence of
the filament immersed in the flame, shown in Figure 6; it is found that these
incandescences are about the same; that is to say, the combustion in the case of
Figure 6, all throughout the flame, is of the same degree as the combustion on the
outer surface of the flame shown in Figure 5.
If now the flame produced by the self burning mixture, as represented in Figure 7
is explored with a refractory thread, it is found that it is raised to an exceedingly
high degree of incandescence in the hyperincandescent zone 17 while in all other
parts of the flaine the incandescence of the thread is comparatively low.
These observations conclusively show that the highest degree of incandescence of
a refractory mantle, would-be- obtained by exposing it to the heating effect of the
hyperincandescent zone of a self burning mixture of air and gas, and it will
presently be shown how this is accomplished.
Suppose a burner, such as described, with an ignited self burning mixture issuing
from the same, be inclined, as shown in Figure 10, so as to make the side of the
hyperiucandescent zone along one line (the generatrix), vertical; and suppose that
a refractory thread 20, also extending vertically, be adjusted either near to or
actually touching or immersed in the vertical portion of the hyperincandescent
zone; then the whole flame will take the shape indicated in Figure 10 and a
considerable portion of the refractory thread will be raised to hyperincandescence.
Supposing now that this whole hypothetical structure be rotated about a vertical
axis, as diagrammatically indicated; it is evident that the hyperincandescent thread
will trace in space the surface of a cylinder, and if rotated fast enough, the eye of
the observer will be impressed as by a hyperincandescent cylinder.
These considerations led to the following construction of my improved incandescent
gas burner, the simplest form of which is shown in Figure 11. In this case, there
is fixed upon the top of the cylinder 13, a conically flaring cup 21, while upon the
cap 16, of the cylinder 15, is fitted a short cylindrical tube 22; and the dimensions
of these two parts are such as to form between their upper edges an annular nozzle,
from which the gas mixture issues in such direction that, when ignited, the outer
surface of the hyperincandescent zone will be vertical, or nearly so, while the inner
surface of that zone will be inclined outwardly. A mantle 23, of refractory threads,
is fitted over the short cylinder 22, and is suspended at its upper end from a copper
book 24 fitted to a looped support 25 also of copper, or other good conductor of heat,
and which is secured to the exterior cylinder of the mixing chamber.
A burner thus constructed does not require a draught of air along the surface of
the mantle of refractory threads, since the combustion of the self burning gas mixture
is perfect without resort to such artificial draught. No glass chimney, therefore,
need be employed. The hyperincandescent zone of the flame of the self burning gas
mixture does extend upwardly, but not throughout the whole length of the mantle;
a portion of the length of the mantle therefore only will be raised to hyperincan-
descence, while the upper portion of it will be heated less, but still to a high degree
of incandescence, and the effect of the whole will be that of an extremely highly
incandescent body, much higher than is obtained by the ordinary incandescent gas
burners.
It is evident that the upper portion of the looped support 25 will be heated con-
siderably by the ascending jet, and being connected with the external cylinder of the
mixing chamber, it will heat the mixture within the same by conduction, which is
an additional advantage.
Instead of making the burner tip in two separate concentric parts 21, 22, the
tip may be stamped out of one sheet of metal, and have the form indicated in
Figure 12, in which case, however the flame will not be completely annular, since
the gas inixture will issue only by the sectoral ring openings 26, or by a number of

page_text: holes, which may be circularly arranged. In each case, however, whatever be the
shape of the burner tip opening or openings, the hyperincandescent zone or zones 17,
of the flame or flames, will have the shape which is indicated in Figure 12, that is to
say, one side will be vertical and the other inclined outwardly.
For a greater amount of light, the duplex structure of incandescent burner, shewn
in Figure 13, may be employed. In this case there are a number of Bunsen pipes,
receiving the gas from a gas chamber 27, upon which they are mounted.. The upper
ends of these Bunsen pipes are fitted into a metal ring 121, which thus forms a common
flange for the upper ends of the suction cones of the modified Bunsen pipes. Into
four concentric grooves, formed in the upper surface of the ring 121, is fitted the
annular mixing chamber 28, composed of two concentric, cylindrical, perforated
diaphragms 131, 1311, and two concentric cylinders 151, 151, both being capped as
shewn. In this case the burner tip is composed of two concentric cylinders 221, 22¹¹,
fitted upon the cap of the cylinders 15¹ 1511, and an annular flaring
trough 21 fitted upon the cap of the diaphragm. In this manner there are, in
reality, produced two concentric annular burner tip openings, which would furnish two
concentric annular flames, each having a hyper-incandescent zone. Upon the short
outside cylinder 22", is fitted the upwardly converging mantle 2311, and within the
inner short cylinder 22¹, is fitted the upwardly diverging mantle 23¹ of refractory
threads. These two mantles being so arranged as to enclose between them an annular
space, both the outer and inner walls of which are exposed to the heating effect of the
hyperincandescent zone of the concentric flames of the self burning gas mixture.
The mantles may be mounted upon rings 30, suitably suspended by hooks 24 from
horizontal arms 32, radiating from a central vertical rod 33, which rises from a cross
piece on the annular base of the burner. A number of short radial arms 35 extending
from the vertical rod 33 are connected with the inner solid wall of the mixing
chamber.
All these connections are made of good conductors of heat so that the gas in the
mixing chamber is heated preparatory to its ignition.
It will be understood that the details of construction of my improved incandescent
gas burner may be varied in a great number of ways, without departing from the
fundamental principles of my invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, "I am aware of the
Specification of Letters Patent, No. 10497, A.D. 1894, granted to De Mare and I
make no claim to anything described or claimed therein, but" I declare that what I
claim is :-
1. The method of raising a refractory body to a high degree of incandescence,
which consists in subjecting the refractory body to the heating effect of the flame
of a self-burning mixture of air and gas in a burner constructed substantially as
described.
2. An annular gas burner tip, for the consumption of a self-burning mixture of air
and gas, consisting of an exterior cylindrical tube and a concentric interior, upwardly
and outwardly widening conical tube whereby the outer surface of the flame forms,
approximately, as a vertical cylinder, substantially as described.
3. In an incandescent gas burner, the combination of a burner tip, such as is
referred to in the preceding claim, with a mantle or hood of refractory threads, as
nearly as practicable, in superficial contact with the cylindrical flame, substantially as
described.
4. An incandescent gas burner, consisting of two concentric mantles or hoods of
threads of refractory material and two concentric annular burner tips, each directing
an annular flame into heating proximity to one of the mantles, substantially as
described.
5. A Bunsen burner for producing a self-burning mixture of air and gas, consisting
of an upwardly converging mixing tube into which the air and gas are admitted, and

page_text: an upwardly diverging suction tube having an angle of divergence of not more than 10°
substantially as described.
6. A Bunsen burner for producing a self burning mixture of air and gas, con-
structed and operating substantially as described with reference to the accompanying
drawings.
ABEL & IMRAY,
Agents for the Applicant.