The flue should be of such a size that it will carry off just as
GAS BURNERS. ' 113
much air as the lamp will remove no more and no less ; and to
do this the height of the flue, the diameter, the number of curves,
and the size and position of the room chimney in respect to the
lamp's position, and again the quantity of the fresh air which is
to be admitted into the room, should all be taken into considera-
tion. If sufficient fresh air is not admitted to supply both the
coal-fire chimney and the lamp, the probability is that the lamp-
flue will be called upon to supply the deficiency, a down-draught
will ensue, and then the lamp will prove an utter failure.
For the supply of fresh air to a ventilating regenerative lamp
there is nothing more simple nor more effective than the Tobin
tube, which can be fitted up in any room at little expense. This
consists of a rectangular tube, say 9 in. by Sin. or 4 in., fixed
against an inside wall, reaching to about 6ft. above the floor, with
a hinged lid on top, and through the wall at the floor level an
opening to the bottom of the tube. By this air is drawn in and
let out above the heads of the occupants of the room, and draughts
are avoided. The tube can be made to fit in the corner of a room,
and need then only consist of a flat board fixed in the angle.
It has been found that a vertical flue, 6 in. diameter, 12 ft.
long, when a gas burner consuming only 1 cub. ft. per hour is
burning inside it, will remove 2,460 cub. ft. of air per hour. Thus
it will be seen that a cubic foot of gas in a ventilating shaft can
be made to remove more than 2,400 times its own bulk of air, and
the gas which is consumed in rooms might thus become a most
valuable adjunct to the ordinary means of ventilation, and
improve sanitary conditions. If each room in which gas is used
were connected to a flue in which a gas-burner could be kept
alight, the products of combustion arising from the use of the gas
might be carried away as rapidly as made, and with them might
be taken the vitiated atmosphere exhaled from the lungs ; the
flue should be made of such a size as to allow of a complete
change in the air of the room every ten minutes. Thus, given ten
rooms, each 12 ft. by 12 ft. by 10 ft., of which it was desired that
the air should be changed entirely every ten minutes : this could
be done with the use of some 36 cub. ft. of gas per hour. But this
is far more than need be allowed in most cases, and it would
probably suffice to allow for only one third of the air to be
changed once every twenty minutes, which would require about
6 cub. ft. of gas. By the consumption of this quantity, absolutely
fresh air might be obtained in the rooms of a ten-roomed house.
/f*& OF THE
The atmospheric and the illuminating flame appear to have the
same effect in all cases where a large quantity of air has to be
heated to a low temperature. The maximum consumption of
gas in a ventilating flue should not exceed 5 cub. ft. per hour for
each circular foot area of section. The remarks previously made
with regard to the necessity of admitting fresh air to equal the
quantity taken out apply in like manner in this case, and the
object may be effected by the same means.
The gas consumption and illuminating power of Sugg's
regenerative lamps are stated by the makers to be as follows :
Hourly Consumption of
3 cubic feet
The following table gives the duty obtainable from burners
of different types when burning 16-candle coal gas :
Light Obtained per
Cubic Foot of W-candle
Flat -flame, No. 7 ...
Following these remarks on the ventilating regenerative
burners, it is appropriate that Strode & Co.'s " Sun Burner "
should receive consideration. This burner was introduced many
years ago, but the patented gas burner and ventilator now on the
Fig-. 9H. Slrode's Sun Burner.
market is a great improvement on the original invention. By
an arrangement of cones, heated air is introduced to support the
combustion of the gas, thus obtaining high illuminating power
and good ventilation of the apartment, the whole of the products
of combustion being carried off through the perforations which
surround the Sun burner cones ; a flue running through the
ceiling is connected to the Sun burner, and discharges the un-
desired gases. Thus the inside atmosphere is not vitiated by
the burning gas, but an efficient system of ventilation is provided.
Of course, the very utmost attention must be given to the ar-
rangement and putting in of the flue, as on the efficiency of
this rest the illuminating power obtained and the working of
the ventilating system. Fig. 96, p. 115, illustrates a pattern
of Strode's Sun burner fitted with an outer ventilating shaft and
an extract wind-guard. The sizes and principal dimensions of
the new patent Sun burners are given in the following short
table, compiled from particulars furnished by the makers :
The principle of the albo-carbon light depends upon the
carburetting of the gas with the vapour of a hydro-carbon
obtained from a solid substance, which may be naphthalene.
Naphthalene is obtained from coal-tar, and has the formula C 12 H 8 ;
it melts at 175 F., and boils at 410 F., but when it is raised
to a temperature of 212 F. a hydro-carbon vapour is given off
sufficient to saturate the gas with its full amount of carburetting
material. Fig. 97 is a sectional view of a common form of
albo-carbon fitting. In most of these fittings is an aperture
for charging the vessel with the small fluted cylinders ; the
aperture is closed by a screwed plug. The gas-supply pipe in
the interior of the vessel is carried sufficiently high to be above
the melted naphthalene, and is bent down, or a hole is made in the
under side of the pipe, so that the gas shall blow directly on the
surface of the carburetting material. The outlet pipe is usually
taken from near the top of the vessel, and is bent downwards 4 in.
or 5 in., and again bent so that a burner may be fixed in a vertical
position. From one side of the vessel, and immediately above
this burner, projects a blade of copper which, being heated by the
flame of the burner when alight, conducts an amount of heat to
the body of the vessel sufficient to vaporise the naphthalene ; so
Fig. 98. Fitted
Fig. 97. Section of Albo-carbon Gas Burner.
Albo-carbon Gas Burner.
that the flame of the burner performs the work of vaporising the
hydro-carbon for its own enrichment . When the gas is first
lighted, the material in the vessel is in the solid form, and it
requires several minutes before the effect of the carburation is
seen ; but gradually the light assumes a peculiar brilliancy,
and the illuminating power of the gas is raised from eighteen or
twenty to about thirty-seven candles. The albo-carbon gas-light
is adaptable to various ways of fitting ; for instance, in Fig. 98
the burners are arranged in a circle above the carburetting
chamber instead of being below it.
The shape of the gas globe has a great eftect upon the amount
118 PRACTICAL GAS-FITTING.
of light given by an ordinary burner, either union jet or batswing.
For many years Mr. Sugg has been showing the necessity of
having a large opening at the bottom of globes in place of the
restricted space which until recently was thought desirable. Now,
the old-fashioned pine moon and open-top globe is falling into
deserved disuse. The advantages of the more modern type are
many, among the foremost being the fact that the light from the
burner can pass unrestricted down upon that portion of the room
which requires the greatest amount of light, and the upper
portion of the globe forms an excellent reflector to aid in th-3
diffusion of light downwards. As in most cases the gasalier is
fixed in the centre of the room over a table, it is generally
required that the light shall be greater immediately underneath
the burner than in the remaining portion of the room. Another
advantage is that a sufficient amount of oxygen is permitted to
pass into the globe to allow of complete combustion of the gas
without unnecessary draught, which would cause the flame to
flicker and take a form in which the perfect combustion of the
gas would be impossible. This is one respect in which the
flat-name differs from the argand, the latter requiring a draught
to cause a perfect flame. Some time back an invention for im-
proving the light from a flat-flame burner when used with the
ordinary globe was brought out by a Mr. Spencer, who designed
and patented a modification of the old-fashioned corona, upon
which he placed a second cap, which was movable, and which
could be made to open or close the apertures in the corona proper,
through which the products of combustion passed. The cause
of the improved lighting effect was no doubt the wanning of the
air during its prolonged contact with the heated globe.
The respective amounts of light obscured by the different kinds
of globes ordinarily in use have been stated thus :
Clear glass globe obscures about 12 per cent.
Glass with slightly ground flowers 24
G lobes of about usual pattern ,, 35
Globes ground all over ... 43
Opal globes 60
Opal globes painted... ,,. ., 04
INCANDESCENT GAS BURNERS.
ALL gas burners that emit light have as much claim to the term
"incandescent" as have those combinations of Bunsen burner
and mantle which now alone are known by that name. The
" incandescent " gas burner differs from any burner described in
the previous chapter in this respect that in the ordinary burner
the light emitted is due to the raising to incandescence of the
carbon particles of the gas itself, whilst in what is known as
the " incandescent " burner the gas is used merely as a heating
agent to raise certain oxides of the rare earths to incandescence.
The incandescent burner consists of two portions, the burner
itself and a cotton hood or mantle which, in the case of the
Welsbach mantle, has been dipped in a solution of the oxides of
rare earths 98 per cent, of thoria to 2 per cent, of ceria. On
burning away the cotton, the oxides remain, and retain the shape
of the original mantle. This is then supported over a Bunsen
burner which, when the gas is lit, fills the body of the mantle
with flame, producing incandescence on its surface, and causing
it to give out a brilliant bluish-white light. The mantles are
about 3 in. long, 1 in. in diameter at the bottom, and are some-
what conical in shape. Across the upper end of the mantle a
thick loop of the material stretches ; this is for the purpose of
supporting the mantle when in use on the fork of a thin fireclay
prop, which passes up the long axis of the mantle and fits into
a cavity in the central conical-headed rod of the burner. A
chimney, 2 in. in diameter externally, and about 8 in. long, fits
over the mouth of the upper end of the burner, which is provided
with a contrivance for diminishing the risk of lighting back.
The ordinary form of incandescent burner is arranged for
a gas consumption of about 3| cub. ft. per hour at a pressure
of 1 in. ; the pressure at which the gas is burnt is a most
120 PRACTICAL GAS-FITTING.
important factor in the results obtainable from this type of burner.
The pressure should never be less than 1 in.
In manufacturing the mantles, ordinary cotton is knitted in
a machine into a cylindrical form, and, to free it from impurities,
it is washed in a solution of hydrochloric acid and ammonia.
It is then placed in a 14-per-cent. solution of the metallic oxides
of some rare earths ; thoria is usually the basis of the light-giving
properties. The mantles are squeezed until only sufficient liquid
is left upon them to soak into all the pores, and are then left to dry.
The upper ends are then sewn so that the mantle may be hung up.
On considerable heat being applied, the cotton fabric is burnt
away. The mantles are very fragile, and so, in order to ensure,
their safety in transport, they are dipped in a solution of collodion,
which has the effect of giving them the necessary stiffness and
toughness to enable them to withstand ordinary handling.
Before the gas is lit, but whilst the new mantle is in position,
this stiffening solution is burnt off by means of a spirit torch ;
tapers or matches deposit soot on the mantle and chimney.
In the 1885 and 1886 patents granted to Welsbach, pre-
scriptions for the mantles are given as in the table on the next
page. The other particulars there tabulated are the results of
In the table given on p. 122, Professor Lewes has brought
together the oxides which have been used in the manufacture of
incandescent mantles, and his results show the amount of light
emitted by each under the conditions existing in the mantles.
The Welsbach incandescent burner is illustrated by Fig. 99, p. 123.
As before explained, it consists of a Bunsen burner in which air
and gas are admixed before the flame-point is reached, forming a
flame of very little illuminating power but of great heat. This
burner should be tightly screwed upon the gas fitting, either
bracket or pendant, the small cardboard washer being put on
first to make the joint tight. The Bunsen burner, when fixed,
must be absolutely plumb, otherwise the flame will not be of the
proper shape, and the mantle, being unequally heated, will in
a short time break up. The lowest pressure at which the in-
candescent gas burners work well is ^ in. of water, but as a
general rule 1-in. pressure is about the best, and this of course
should be measured at night when the lights are likely to be
most in use. If the screw upon the Buusen burner tube is too
small for that on the fitting, a double screw-piece called an
INCANDESCENT GAS BURNERS.
adapter which is supplied with each burner, should be fixed
with the cone-shaped end into the fitting. A disc is also sup-
plied ; this is intended to prevent lighting back in the Buusen
tube. " Lighting back " is the term used for the lighting of the
WELSBACH 1885 PATENT.
I. < Lanthania . . .
i Yttria ... 20
Ji ' I Lanthania ...
WELSBACH 1886 PATENT.
j 1 Thoria
I Magnesia ...
II. < Zirconia
III. -I Zirconia
I Lanthania ...
IV. < Magnesia ...
[ Lanthania ... 40
f Thoria ... 60
V. < Magnesia ... 20 1 J-
I Alumina ...
small inner gas-supplying tube before the admixture with the
air has taken place ; lighting back heats the fittings unnecessarily
and causes a disagreeable smell. When lighting back happens
the gas should be turned out, and in a few seconds it can be
re-lighted. The next portion to fix is the gallery, which carries
both the mantle and the chimney. It is as well now to light up
the gas and find out if the fitting is upright and the flame correct
in every particular a very important point. The correct flame
is of a clear reddish colour, about 4 in. high, and should crackle
and bubble. If the flame does not reach this height when the
gas is fully turned on, enlarge the gas holes at the top of the gas-
supplying tube with a broach or tine reamer ; make the enlarge-
ment from the same direction as that in which the gas enters.
If, on the other hand, the gas-flame be too large, the gas-supplying
holes should be burred over until only 3j cub. ft. of gas will pass
PROFESSOR LEWESS TABLE.
CANDLES PER CUBIC
FOOT OF GAS.
\ Zirconia 1 o
Pprifp "Fartliu f Ceri.i 0'4
3 iLartus < Lanthania
Ytterite Earths ||;J^ " ( ^
Common f Chromium ... j 0'4
Earths 1 Alumina ... ; 0'6
\lkaline (Baryta | 3*3
VaH-h AfpfnU 1 oironud
[ Magnesia 5'0
at 1-in. pressure. It should be mentioned that only a small
difference in size is necessary, and that all the gas-holes should be
equally enlarged or closed. The mantle should be gently shaken
out of the box or cardboard tube and held by the loop by which
it is then suspended over the fork on the porcelain rod, while the
bottom of the mantle hangs over the neck of the gallery. The
gas must not be turned on and lit until the flame of a spirit lamp
has been held to the bottom of the mantle, when the toughening
coating upon the mantle will be quickly burnt off and leave the
mantle ready for use. All that remains to be done is to fix the
chimney straight upon its gallery.
INCANDESCENT GAS BURNER 8.
The form of incandescent burner most to be preferred is one
with a bye-pass that is, a small pilot light, which Should only be
I in. high ; Figs. 99 and 100 show bye-pass burners, the former
an ordinary burner, and the latter the new type. In fixing an
Hi? 1 *
Fig. 100. Kern
ordinary bye-pass burner, take care that the bye-pass tube up
the centre of the Bunsen burner fits properly into the groove in
the gallery, or imperfect combustion, and an unpleasant smell,
will result The gas consumption of the bye-pass or pilot light
is insignificant, and is regulated to a nicety by a little screw at
the bottom of the burner. A small lever is fitted to these
burners for the purpose of lowering the light ; sometimes, as in
Fig. 99, the lever has chains. Where this form of burner is in
use no torch is required, as immediately the gas is turned on at
the tap the burner is alight. The bye-pass burner is more
economical as regards mantles, as the light is applied to the gas
at the best point, and no explosion occurs.
A new Welsbach burner known as the Kern is illustrated
by Fig. 100, and differs as is apparent from the older kind or
"C" burner, illustrated by Fig. 99. It is supplied with or
without the bye-pass, the one illustrated having this important
accessory, however. Though the Kern burner differs from the
" C " burner in general construction, yet in broad principle it is
the same, inasmuch as both, of course, are Bunsen burners. The
advantages of the new burner are : (1) An illuminating power
of from 25 to 30 candles per cubic foot of gas as compared
with the 16 to 18 candle-power of the "C" burner. (2) A
governor is not necessary ; increase of pressure involves increase
of light, whereas in the " C " burner, increase of pressure in the
absence of a governor causes the deposition of soot on the
mantle. (3) The new burner does not require a chimney.
The ordinary ("C") Welsbach burner is of three types.
First, the actual " C " burner, consuming about 3| cub. ft. of gas
per hour, and giving a 60-candle-power light ; second, the " S,"
consuming 2^ cub. ft. of gas, and giving a light of 35 candles ;
and third, the " Gem " burner, consuming If cub. ft. of gas, and
yielding a light of 35 candle-power. The l< New " Welsbach
burner is made in the following sizes :
at li?(. pressure.
INCANDESCENT CMS BURNERS. 125
In transferring a mantle from its box to the burner, take
the two ends of the string in one hand and lift the mantle out of
the paper tube. By holding the top part of the burner in the
other hand and below the mantle, the latter can safely be lowered
into position. Before fixing the chimney, examine the mantle, as
a faulty one will be exchanged by the dealer if returned before
being lit. A mantle is made up of a regular series of loops, each
row connected to the one above, and if at any point a'loop does
not join the row above, the mantle should be returned as faulty,
as it is almost certain to develop a break as soon as used. Other
faults, such as broken collars, broken suspending loops, fractured
sides, and torn bottoms, are noticeable at a glance.
When lighting incandescent burners, a spirit torch should be
applied from underneath the chimney, but above the disc which
prevents lighting back ; the spirit torch does not blacken the
chimneys as do tapers or matches. Some people prefer to light
from the top of the chimney, in which case the gas should be
turned on sufficient time before the light is applied to allow the
gas to expel all the air in the chimney, so that little or no
explosion shall take place, and the mantle may be free from
The breakage of mantles when in position may be avoided by
attention to a few rules. Fix incandescent burners only on good
sound and clear gas fittings. Where there is much vibration, use
one of the anti-vibration frames now on the market ; these
frames are specially suitable for hanging lights, such as the arc
lamps, etc. All pendants for the incandescent light should be
supplied with cup and ball joints, and they should never be
screwed stiff, or the mantle will break if it gets the slightest
knock. In draughty places, such as lobbies, passages, and
corridors, a mica chimney is desirable, so as to avoid breakage
of the chimney, and to preserve the mantle.
If a newly fixed burner gives an unsatisfactory light, either
there may be an insufficient gas supply, or the mantle may be
much too wide ; perhaps both conditions exist. In the first case the
mantle will be well lit all round the bottom with the light getting
worse towards the top. If two of the four air-holes in the Bunsen
tube are covered by the fingers, the light will at once improve.
Therefore, either reduce the amount of air admitted, or increase the
quantity of gas supplied. To reduce the amount of air, unscrew
the Bunsen tube and fix inside it a piece of card or tin to cover
126 PRACTICAL GAS-FITTING.
two opposite holes. To increase the gas supply, remove the
burner from the fittings, and unscrew the Bunsen tube, when the
gas regulator nipple will be seen to consist of a brass tube having
a soft white metal top with five small holes, which should be very
slightly enlarged. Very handy for this purpose is a hat-pin, ground
to a long taper and passed up from the under side. When a mantle
is too wide, one side only is incandescent, the other side hanging
away from the gas ring. This fault is, of course, easily seen
before the burner is used ; if, however, the mantle has been lit,
the light can be improved by slightly lowering the mantle and,
as this is tapered, presenting a smaller surface to the flame.
Take off the mantle, lifting it by a wire under the suspending loop.
Then place the wire across a glass tumbler with the mantle
suspended inside. Take out the support, nick it with a file about
-o in. from the plain end, and break it off. Finally replace the