Improvements in Incandescent Lighting by Means of Calefacient Gases and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 12th May, 1890
Complete Specification Left, 10th Nov., 1890-Accepted; 28th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Incandescent Lighting by Means of Calefacient
Gases and in Apparatus therefor.
1, GEORGE MACAULAY-CRUIKSHANK, C.E., of 62, Saint Vincent Street, in
the City of Glasgow, Registered Patent Agent and Fellow of the Institute of
Patent Agents, do hereby declare the nature of this invention (a communication to
me from abroad by José Carlos Reissig, La Plata, Argentine Republic, Gentleman,
Patrick Fraser Maccallum, Fairbank, Helensburgh, in the County of Dumbarton,
Scotland, presently of La Plata, Argentine Republic, Engineer, and John Laudin,
Regeringsgatan 58, Stockholm, Sweden, Engineer) to be as follows:
:-
This invention relates to improved methods of applying the calorific power of
calefacient gases, burnt by means of burners giving flat flames applied to refractory
substances manufactured into small bars, rods or needles and arranged in such a
way that the small bars, rods or needles may be effectively heated by the flames
issuing from the burners.
"
This invention is primarily applicable to what is known as the "Fahnehjelm
system of incandescent lighting; but it may also be applied to other systems in
which the illumination is produced by the incandescence of refractory substances,
metallic or otherwise, produced by the calorific power of calefacient gases burnt by
means of ordinary flat flame burners, such as are generally called "fish tail" or
batwing burners.
In the "Fahnehjelm " system, as practically applied, a number of small rods of a
specially refractory composition arranged generally in two straight and parallel
rows, are fixed by a suitable cement in a metallic socket; the aggregation of small
rods together with the socket being termed a "comb." These combs are suspended
at a suitable height above ordinary flat flame burners, such as Brays No. 3,
and rendered highly incandescent by the combustion of what is called "water
gas."
These combs have heretofore been used vertically, in which position they give
an excellent illuminative effect in directions at right angles to the planes of the
combs, but not equally in other directions, in proportion to the absolute photo-
metric power of the lights.
The first part of the invention consists, with a view to obtain a better down-
ward and more equal illumination,-in inclining the combs and burners to
any required angle and furthermore in ensuring sufficient contact of the calefacient
flame with the comb, by placing a plane of any sufficiently refractory material,
preferably with a reflecting surface, immediately above or behind the combs in such
a way as to guide the calefacient flame in the direction of the axes of the refractory
bars, rods, or needles, forming the comb, and to neutralise as far as possible any
tendency of the calefacient flame to leave the comb through the action of upward
currents of air.
We call the planes placed above the burners and combs "guide reflecting
surfaces," because they serve the two-fold purpose of guiding or directing the
flames and reflecting the light produced by the action of the flames on the
refractory bars rods or needles forming the combs. When the lights are used
without regeneration, the guide reflecting surfaces should preferably be of a non-
conducting material in order that as little heat as possible may be abstracted from
the comb; but when the lights are used regeneratively, in the ways to be hereafter
described, the guide reflecting surfaces may be of metal polished or coated with

page_text: any suitable reflecting substance. The guide reflecting surfaces should not be
placed so near the comb as to come into actual contact with the flames, and we
recommend that they should not be placed at a greater distance from the comb
than about one inch. "In practice 'we have obtained excellent results with a
space of three-eighths of an inch between the combs and the guide reflecting
surfaces.
Single combs may be treated as above described for use as wall or bracket lamps
or any number of combs inclined to any desired angle may be grouped together in
proximity with guide reflecting surfaces arranged so as to project the light in any
desired direction. When a number of flames are thus arranged in a circle so as to
give an equal illumination in all directions the guide reflecting surfaces form an
inclined polygonal vessel of some depth with a flat surface opposite each flame,
and when the number of flames is considerable the inclined reflecting vessel may be
made circular. These reflecting vessels may be of any diameter to suit the number
of flames required; but when lamps of very great power are required it is preferable
to keep the diameter within certain limits and to arrange the reflecting vessels and
flames in tiers or rows one above the other.
In the Fahnehjelm system as practically applied the combs are supported in the
proper position above the burners by means of small metallic wire supports resting
in sockets attached to the gas brackets. But in lamps of the construction described
the wire supports may be dispensed with and the combs attached directly to the
guide reflecting surfaces.
When an absolutely downward illumination is required the combs and burners
with the guide reflecting surfaces above them may be fixed horizontally or almost
horizontally.
The invention further consists, with a view to obtain improved illuminative
effect and economy in consumption of gas, in applying the principle of regenera-
tion or recuperation to lamps of the types already described. We accomplish this
by utilizing the sensible heat of the products of combustion or waste gases for
heating the air or a portion of the air required for combustion or for heating both
the gas and 'the air or for heating the combustible gas alone according to the
methods about to be explained.
We may first describe our mode of making a lamp partially regenerative and in
order that our explanation may be better understood, we may take the case of a
suspended eight flame lamp giving with water gas an illuminative effect of from
250 to 300 candles. The upper and lower ends of the inclined guide reflecting
vessel surface which in such a lamp forms an inclined ring of octagonal or circular
section are closed in such a way as to convert the interior of the guide reflecting
surface into an enclosed and practically air tight chamber, somewhat resembling an
inverted cone with the gas pipe or pipes passing downwards through its axis to the
lower end, where the pipe or pipes are branched in any convenient way for
connection with the burners, which are so arranged as to bring the flames into the
required proximity with the guide reflecting surfaces. A hood somewhat larger
than the upper part of the reflecting surface, with a chimney of sufficient length is
placed above the lamp so as to cause a large proportion of the hot products of
combustion to pass under the hood and up the chimney, through which descend
the gas supply pipe or pipes for the supply of the burners. The combustible gas
is thus considerably heated before it arrives at the burners, with a correspondingly
beneficial effect on the illumination. Some of the air for combustion may also be
heated by allowing it to enter the lower part of the reflecting vessel, and causing it
to pass either through small pipes, or between flat surfaces or through perforated
plates to suitably arranged orifices in the guide reflecting surfaces in proximity to
the points of combustion of the several flames. As the air chamber becomes
highly heated after the lamp has been in operation for a short time a considerable
degree of heat is imparted to the air passing through, it, with a correspondingly
beneficial effect on the illumination.

page_text: A still more simple form of lamp may be constructed by merely connecting the
closed reflecting vessel with the gas supply pipe. The reflecting vessel then
becomes a gas chamber or reservoir from which the gas may be led directly to the
burners.
To render the lamp fully regenerative with a view to obtain the highest
illuminative effect with the greatest economy in the consumption of gas the flames
must be enclosed in a glass globe or lantern and the whole volume of hot waste
gases caused to pass into the chimney. The air for combustion may be either
introduced above the globe or lantern by means of suitably arranged pipes or
canals, and led into the interior of the highly heated reflecting vessel, or
may be
introduced through a pipe or pipes passing from the bottom of the reflecting vessel
downwards through the bottom of the globe or lantern, and so communicating with
the external atmosphere. In either case the air after being subjected to sufficient
contact with heated surfaces issues through orifices in the sides of the reflecting
vessel, placed in proximity with the points of combustion of the several flames.
This form of lamp may be provided with a regulating valve placed at the bottom
of the globe or lantern, for the admission of an auxiliary air supply which may be
used when the lamp is newly lighted, or at any time to prevent an inconveniently
high temperature in the lamp.
Though the foregoing methods of rendering lamps partially or wholly
regenerative have been explained with reference to circular or polysided lamps,
they are equally applicable to square lamps, or to lamps which project the light
only on one side.
When the lamps are used with an ascending gas supply, as in the case of street
lamps, the supply pipe may either be passed directly upwards through the globe
or lantern and air vessel to the chimney, and then returned downwards to the
burners; or it may be bent or branched below the lamp and led into the upper
part of the chimney from the outside.
The following matter describes a method by which the illuminating power of the
ordinary Fahnehjelm light, with the combs suspended vertically above the burners,
either singly or in groups of two or more, may be considerably improved. The
burners and attachments are enclosed in a metallic shield or case of some depth,
arranged in such a way as not to interfere appreciably with the downward
illumination. The upper sides of the shield approach closely to the points of the
incandescent needles, thus enclosing the calefacient flame and protecting the same
from transverse air currents without interfering with its proper combustion. The
shield or case becomes highly heated and in turn imparts heat to the air ascending
through it to the burner, with a correspondingly beneficial effect on the illumination.
A further improvement may be effected by spreading out the upper part of the
shield, or by attaching thereto a glass plate or saucer, so as to form a rest for a
glass globe or for a glass chimney, such as are used for some kinds of petroleum
lamps. The combs then become completely enclosed and all the air for combus-
tion must pass through the heated metallic case to the burners.
As an improvement on the usual methods of producing the flat flames required
to render the combs incandescent we propose to modify the above described metal
shield or case in such a way as to convert it into a flat burner of the Bunsen type,
producing a flat flame of the required dimensions so that the use of ordinary
burners may be dispensed with.
Dated th
1 - 1000
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents

page_text: COMPLETE SPECIFICATION.
Improvements in Incandescent Lighting by Means of Calefacient
Gases and in Apparatus therefor.
I, GEORGE MACAULAY-CRUIKSHANK, C.E., of 62, Saint Vincent Street, in the
City of Glasgow, Registered Patent Agent and Fellow of the Institute of Patent
Agents, do hereby declare the nature of this invention, and in what manner the
same to be performed (as communicated to me), to be particularly described and
ascertained in and by the following statement :-
This invention relates to improved methods of applying the calorific power of
calefacient gases burnt by means of burners giving flat flames applied to refractory
substances manufactured into small bars, rods or needles, and arranged in such a
way that the small bars, rods or needles may be effectively heated by the flames
issuing from the burners.
"
The invention is primarily applicable to what is known as the " Fahnehjelm
system of incandescent lighting but it may also be applied to other systems in
which the illumination is due to the incandescence of refractory substances (metallic
or otherwise) produced by the calorific power of calefacient gases burnt by means
of ordinary flat flame burners such as are generally called "fish tail or bat wing
burners or by combinations of burners producing flat flames.
"
In the "Fahnehjelm " system, as practically applied, a number of small rods of
a specially refractory composition, arranged generally in two straight and parallel
rows, are fixed by a suitable cement in a metallic socket, the aggregation of small
rods together with the socket being termed a "comb." These combs are suspended
at a suitable height above ordinary flat flame burners, such as Bray's No. 3 union
jet or slit burners and rendered highly incandescent by the combustion of what is
called "water gas." The combs have heretofore been used vertically, or nearly
so, in which position they give an excellent illuminative effect in directions at
right angles to their planes, but not equally in other directions, in proportion to
the absolute photometric power of the lights.
"
The first part of the invention consists (with a view to obtain a better downward
and more equal illumination) in inclining the combs and burners y to any required
angle as seen by Figures 2, 3, 4, 5, 6 and 9 of the accompanying drawings, and
furthermore in ensuring sufficient contact of the calefacient flame with the comb by
.placing a plane a of any sufficiently refractory material metallic or otherwise pre-
ferably with a reflecting surface, immediately above or behind the combs in such a
way as to guide the calefacient flame in the direction of the axes of the refractory
bars, rods or needles forming the comb, and to neutralise as far as possible any
tendency of the calefacient flame to leave the comb through the action of upward
currents of air.
وو
The planes a placed above the burners and behind the combs are called "guide
reflecting surfaces because they serve the twofold purpose of guiding or directing
the flames and reflecting the light produced by the action of the flames on the
refractory bars, rods or needles forming the combs. The guide reflecting surfaces a
should not be placed so near the comb as to come into actual contact with the
flames, and it is recommended that they should not be placed at a greater distance
from the comb than about one inch. In practice excellent results have been
obtained with a space of three-eighths of an inch between the combs x and the guide
reflecting surfaces.
Single combs may be treated as above described for use as wall or bracket lamps
or any number of combs inclined either from or to each other to any desired angle
may be grouped together in proximity with guide reflecting surfaces arranged so
as to project the light in any desired direction. When a number of flames with
the burners inclined outwards are thus arranged in a circle so as to give an equal
illumination in all directions the guide reflecting surfaces a form an inclined polygonal
yessel of some depth with a flat surface opposite each flame or when the number of

page_text: flames is considerable the inclined reflecting vessel may be made circular. These
reflecting vessels may be of any diameter to suit the number of flames required;
but when lamps of very great power are required it is preferable to keep the
diameter within certain limits and to arrange the reflecting vessels and flames in
tiers or rows one above the other.
In the Fahnehjelm system as practically applied the combs are supported in the
proper position above the burners by means of small metallic wire supports
resting in sockets attached to the gas brackets as seen at Figure 1 of the
drawings, but in lamps of the construction herein described the wire supports may
be dispensed with and the combs attached directly to the guide reflecting surfaces
by brackets as at Figure 2.
When an absolutely downward illumination is required the combs and burners
with the guide reflecting surfaces above them may be fixed horizontally or almost
horizontally.
The invention further consists with a view to obtain improved illuminative effect
and economy in consumption of gas, in applying the principle of regeneration a
recuperation to lamps of the types already described. This is accomplished by
utilizing the sensible heat of the products of combustion or waste gases for heating
the air or a portion of the air required for combustion or for heating both the gas
and the air or for heating the combustible gas alone according to the methods about
to be explained.
Figure 3 of the drawings illustrates in vertical section a suspension four flame
lamp constructed in accordance with the invention and which is partially regenerative
the gas inlet pipe d passing downwards through the chimney c and through the
reflecting vessel a the upper and lower part of which are closed in such a way as
to convert the interior into a practically air tight chamber somewhat resembling an
inverted pyramid and the gas is thus considerably heated before it reaches the
burners y, some of the air for supporting combustion may also be heated by con-
ducting it through tubes e which pass through the interior of the reflecting vessel a.
A hood w somewhat larger than the upper part of the reflecting vessel a is placed
above the lamp the chimney being connected to the said hood to conduct away
the hot products of combustion.
As the interior of the vessel a becomes highly heated after the lamp has been in
operation for a short time a considerable degree of heat is imparted to the air
passing through the tubes e with a correspondingly beneficial effect on the
illumination.
A glass tray is provided below the burners y to arrest any falling particles
of magnesia.
A still more simple form of lamp may, as seen in vertical section at Figure 4, be
constructed by merely connecting the closed reflecting vessel a with the gas supply
pipe d. The reflecting vessel then becomes a gas chamber or reservoir from which
the gas is led directly to the burners.
Figure 5 illustrates in vertical section a fully regenerative lamp constructed with
à view to obtain the highest illuminative effect with the greatest economy in the
consumption of gas the flames being enclosed in a glass globe or lantern and the
whole volume of hot waste gases caused to pass into the chimney c. The whole of
the air to support combustion may be introduced above the globe or lantern through
tubes e and led into the interior of the highly heated reflecting vessel a and an
auxiliary supply may also be introduced through a valve g in the bottom of the
lantern or as seen at Figure 6 the air may be introduced through the lantern into
tubes e passing to the interior of the vessel a, and thence through tubes e² to the
burners in which case a valve g for the admission of an auxiliary supply of air when
necessary is also provided. In either case the air after being subjected to sufficient
contact with heated surfaces issues in proximity to the points of combustion of the
several flames.
When the lamps are used with an ascending gas supply, as in the case of street
lamps, the supply pipe ; may either be passed directly upwards through the globe

page_text: or lantern and air vessel to the chimney, and then returned downwards to the
burners; or as seen at Figure 6 it may be bent or branched below the lamp and led
into the upper part of the chimney from the outside.
Figures 7 and 8 of the drawings illustrate in side elevation and in transverse
vertical section a simple method of increasing the illuminating power of the
Fahnehjelm comb. As shewn by these figures a metallic shield k encloses the
burner and a part of the calefacient flame. In the drawings the comb a is shewn
supported in the usual way but it may be attached directly to the regenerative
shield. When a funnel m is employed a rest plate or gallery n of glass or metal is
attached to the shield to support it in proper position. The shield k is so arranged
as not to interfere appreciably with the downward illumination and its upper sides
approach closely to the points of the incandescent needles, thus enclosing the
calefacient flame and protecting the same from transverse air currents without
interfering with its proper combustion. The shield or case k becomes highly heated
and in turn imparts heat to the air ascending through it to the burner, with a
correspondingly beneficial effect on the illumination. The rests or galleries
be perforated to ensure the supply of sufficient air to promote complete combustion
of the gas.
n may
Figure 9 is a vertical section of an arrangement of four flame lamp with combs
inclined inwards or towards each other and in which the gas descends through
pipes o placed in the chimney and communicating at their lower ends with an
annular chamber a' made in the reflecting vessel a and from whence the gas passes
to the burners y the air to support combustion being admitted through the pipes p
or through orifices p' above the glass door or globe or part of the air may be
admitted through both sets of openings p, pl.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to me,
I declare that what I claim is :-
1. The method of increasing the effective illuminating power of flat flame
incandescent lights consisting in inclining the burners and combs to any desired
angle from the perpendicular and in placing above or behind them suitable reflecting
surfaces as described with reference to Figs. 2, 3, 4, 5, 6 and 9 of the accompanying
drawings.
2. The application of the regenerative principle fully or partially to the class of
flat flame incandescent lights, hereinbefore referred to substantially as described
with reference to Figs. 3, 4, 5, 6 and 9 of the drawings annexed.
3. The application of the air heating and flame protecting shield k to flat flame
incandescent lights, either singly or in groups of two or more, and either in vertical
or inclined positions substantially as described with reference to Figs. 7 and 8 of
the appended drawings.
4. The combination of the air heating and flame protecting shield k with a glass
funnel, as described with reference to Figs. 7 and 8 of the accompanying drawings.
Dated this Eighth day of November 1890.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.