Improvements in Acetylene Gas Burners for Use in Incandescent Lighting.
Year: 1899

page_text: Date of Application, 18th Nov., 1899-Accepted, 23rd Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Acetylene Gas Burners for Use in Incandescent
Lighting.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by the Compagnie Française de l'acetylène dissous,
of 28, Rue St. Lazare, Paris, in the Republic of France) and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement:-
The employment of acetylene gas for rendering mantles made of oxides of the
rare earths incandescent is attended with considerable difficulty. Where the
amount of air drawn in with the gas is sufficient to ensure complete combustion
the mixture becomes so highly explosive that the flame cannot be maintained at
the end of the tube, but fires back into the interior, produces a slight detonation,
and ignites the jet of gas as it issues from the injector nozzle. If, to obviate this
defect, the quantity of air drawn in be reduced an almost steady flame is obtained,
but the light is far from being so efficient as that of a flame from gas sufficiently
rich in air.
The object of this invention is to provide means by which the aforesaid difficul-
ties are overcome. In a burner made acording to this invention the mixture of
acetylene gas and air escapes through orifices; which are sufficiently narrow to
prevent back firing through them. But this alone is not sufficient, as if, through
a sufficiently narrow orifice, a completely combustible mixture of air and acety-
lene gas (say, one of 93 per cent. of air and 7 per cent. of acetylene), issues at a
speed of 4 metres per second, corresponding to about 1 millimetre of pressure.
the propagating, or spreading, velocity is upwards of 6 metres, and the flame will
tend to re-enter the orifice at a speed of 6 metres minus 4 metres. The flame
is checked by the cooling effect produced upon it by the walls of the orifice, but
these walls gradually become so heated that back firing takes place. This would
he prevented from occurring if the speed with which the mixture of air and acety-
lene escapes exceeds the propagating or spreading velocity (6 metres in the
example given). It is however very difficult in the case of injectors arranged for
the usual acetylene gas pressure (from 12 to 13 centimetres of water), to obtain
an adequate amount of energy to ensure the passage of the mixture through the
narrow orifice of the burner at so high a speed. To overcome this difficulty the
mixture of air and acetylene gas is so proportioned as to contain less air than
is theoretically necessary for complete combustion. In such a mixture the spread-
ing velocity of the flame is under 6 metres and it therefore becomes possible to
cause this mixture to issue at a rate of speed practically equal to that of the
spreading velocity. The heating of the material in which the orifices are formed

page_text: is then kept sufficiently low, the heat imparted thereto being abstracted at an
almost equal rate by the heat-conducting property of the said material.
But as the gas mixture is not sufficiently rich in air it would not be capable of
illuminating the mantle in a manner satisfactory on economical grounds.
The accompanying drawing represents in vertical section in Fig. 1 and in
plan in Fig. 2 a burner made in accordance with this invention. The orifices
are formed by tubes abe arranged at considerable intervals apart and surrounded
by a convergent outer tube & the wider end of which is downwards and admits
external air while its narrower upper end is within the lower part of the mantle.
The air issuing through this narrower end is distributed around the tubes abc
and the flames therefrom and effects complete combustion of the gas.
The aforesaid tubes in order to prevent an inward return of their flames, should
have very small diameters and, even then, it would be impossible to overcome by
the power of the injector alone the resistance which they would offer to the pass-
age of the gas mixture.
To reduce this resistance as much as possible while at the same time increasing
the efficiency of the injector, according to this invention, instead of employing
tubes which theoretically should be one millimetre in diameter at most, tubes are
employed which are of a diameter of several millimetres each, and which conse-
sequently offer far less resistance to the passage of the gas mixture. These tubes
are flattened at their outlet ends or orifices so that their sectional outline is
approximately rectangular and so narrow as to prevent back firing. The manner
in which they are flattened is clearly illustrated in the drawing.
The effect of this arrangement is not to flatten the gas jet to lamina shape
until it reaches the point of its outlet, and reduce the resistance to a minimum
and a very effective result is obtained.
The injector must be such that sufficient power is given to drive the gas
mixture through the tubes and flattened orifices and such power is not provided
by ordinary injectors.
According to this invention the passage into which the acetylene gas is in-
jected consists of a narrow cylindrical portion e, flaring at its lower part f, and
continued above by a conical portion the walls of which are inclined slightly.
Into the cylindrical part through its lower flaring end the air and gas pass from
the injector at a high speed but in the conical part, the speed of the mixture of
gas and air becomes gradually lessened and its pressure increased. By this
means there is obtained for example with acetylene gas from 13 centimetres of
water, a mixture of air and gas having a pressure of from 1 to 2 millimetres of
water, and this pressure is sufficient to cause the mixture to escape through the
tubes and orifices with the proper speed to prevent back firing.
The parts may be connected in any convenient manner for example the tube d
may be connected by arms to a tube 7 supported by a shoulder or head on the
injector, and the said tube d may be provided with a gallery j to support a chim-
ney or globe. Secured to the tube at k, may be a pinching screw device to
carry the rod for supporting the mantle. From a burner constructed as described
a light of a power of between 50 and 100 candles can be obtained with a consump-
tion of 2 litres of acetylene gas per candle power per hour.
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. In incandescent acetylene gas burners an injector wherein the suction and
mixing tube is formed of a flaring part f a cylindrical passage e and an elongated
conical passage substantially as hereinabove described and illustrated in the
accompanying drawings.
2. In incandescent acetylene gas burners a chamber from which tubes arranged
at intervals apart are led the said tubes being flattened at the exit orifice sub-
stantially as herein before described and illustrated by the acompanying drawings.

page_text: 3. In incandescent acetylene gas burners a tube such as d for admitting air into
the mantle substantially as hereinbefore described and illustrated in the accom-
panying drawings.
4. An incandescent acetylene gas burner constructed as hereinbefore described
and illustrated in the accompanying drawings.
Dated this 18th day of November 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.