MULTIPLE GAS LIGHTING.
[Illustration: FIG. 7.]
As we have already seen how a spark is exhibited at an interrupted
contact, the means of its application to gas lighting will be
considered. Fig. 7 represents the most generally used kind of electric
gas burner or “pendant burner.” Its application is shown in Fig. 8.
The wire _W_ from the coil _C_ is attached to the brass insulated
collar carrying the contact _S_. The other wire from coil _C_ and
battery _B_ is attached to the gas pipe _G_. As the burner is also
screwed into the gas pipe itself, the circuit would be closed were it
not for the gap at _A_ on the burner, caused by the collar carrying
the contact _C_ and wire _W_, being insulated from the burner pillar
_P_. When, however, a pull is given to the burner arm chain so as to
cause the end of the spring _R_ to strike contact _C_ in passing,
contact is made and broken, and a spark passes which ignites the gas
issuing from the burner tip, the gas having previously been turned on.
A piece of chain with a metal ball is attached to the burner arm in
order to pull it down. In this class of burner there are many
different makes differing only in minor details.
[Illustration: FIG. 8.]
Fig. 9 shows a form of pendant burner which has no platinum contact,
but has a broad lug on the insulated collar which is scraped against
by the spiral spring when the arm is pulled down. It will be seen that
the lug is not held by an insulated collar on the burner top, but is
on the extension of an arm attached to the burner pillar by a large
screw and insulating washers. The circuit wire goes under the smaller
screw seen on the lower part of the contact arm, this forming a
strong and neat form of attachment.
[Illustration: FIG. 9.]
Now it has heretofore been necessary to turn on the gas before pulling
the chain of a pendant burner, but as this is not always desirable the
ratchet burner is made. Fig. 10 shows burner carrying a toothed wheel,
which is partly rotated when the arm is pulled down. This wheel is
mounted on the stem of a valve which opens or shuts according to the
point of rotation, and thus shuts off or admits the gas to flow up to
the burner. One pull of the arm turns the gas on; at the same time the
wipe spring touches the contact on burner collar, and the gas lights.
A second pull and the wheel, rotating, turns off the gas. In all
burners of this class a spring is provided to carry the arm up and
back into its original position ready for another pull. Some burners
do not make contact when the arm flies back, thus saving battery
current.
[Illustration: FIG. 10.]
[Illustration: FIG. 11.]
Fig. 11 is an improved form of burner wherein the movable electrode
does not pass through the gas flame, neither do the electrodes come in
contact with each other when the gas is being turned off. Reference
to the cut will show a pin protruding from the base of the coiled
spring electrodes, which pin is so arranged as to come in contact with
the short end of the pull-arm. When this pull-arm is pulled down it
pushes up this pin, elongating the spiral spring electrode
sufficiently to make and break contact at the fixed electrode on the
burner collar. This burner can be fitted with a porcelain candle slip
if desired to match the imitation candle burners.
STEM BURNERS.
Objection is sometimes made to the ordinary chain pulls from the fact
that they jar the fixtures, and also are liable to bend the fixture
branches from the strain used in operating the arm. To overcome these
objections the stem style of burner is manufactured (see Fig. 12).
This stem, it will be seen, carries a convenient key at the end, which
is turned either right or left as in an ordinary gas-cock. The moving
contact only makes contact when the gas is being turned on and
lighted. When turning it off, the arm is retracted so as not to touch
the fixed electrode, thus saving battery current.
[Illustration: FIG. 12.]
Fig. 13 is a simple lighting attachment for an Argand burner. The
moving lever which carries the pull has a German silver spiral spring
on its top end. This strikes against the lug projecting from the
circuit-wire arm and makes a spark. The lower part of the circuit-wire
arm has a screw and washers for ready attachment, and is strongly and
substantially made.
[Illustration: FIG. 13.]
A means of igniting the gas from a Welsbach burner is shown in Fig.
14, and is so simple as to need no further explanation.
ACETYLENE BURNERS.
Owing to the deposits of carbon, it is necessary to construct burners
for acetylene gas in a different and more substantial manner than
those designed for coal gas.
[Illustration: FIG. 14.]
The best arrangement is depicted in Fig. 15, which has a pilot-tube
burner as well as the two main tips. On turning the key, gas is
admitted to both main and pilot burners, but the electrode in
breaking contact only ignites the gas at pilot burner, which, in its
turn, acts as a lighter for the main burner. Turning the main burner
out, the pilot light can be left burning if desired, giving a small
light, it being not feasible to turn _down_ the main burner owing to
the before-mentioned carbonization.
[Illustration: FIG. 15.]
The orifice of an acetylene burner is much smaller than that of a coal
gas burner, the former burning about one-half foot per hour, against
six or seven feet of the latter.
BURNERS FOR GASOLENE.
The flame from this gas is hotter than that of coal gas, and deposits
so much more carbon that a slight modification is necessary in the
construction of burners for it. The details can be readily seen on
observation of a burner, being simply in the adjustment of the
contacts and their operation. It is better, however, to use a larger
coil and a stronger battery for gasolene gas lighting than would be
needed for coal gas--say, 6 cells of Samson, or large-size New
Standard dry battery and a 10-inch coil having about 4 pounds or more
of wire on it.
AUTOMATIC BURNERS.
[Illustration: FIG. 16.]
There are several forms of these burners, but the principle of all is
the same. A gas burner protrudes from the top of a brass case which
encloses the actuating mechanism. This mechanism consists generally of
two electro-magnets, the armature of one opening the valve and
allowing the gas to flow, at the same time vibrating a platinum-tipped
rod against an electrode upon the burner collar. This produces a
series of sparks at the burner tip which ignites the gas. A second
magnet is provided which shuts the valve and extinguishes the gas.
Some devices use one electro-magnet to both open and close the valve,
but the majority have double electro-magnets. The circuit is worked
from a push button, Fig. 16, situated wherever desired; pressure on a
white button lights the gas and on a black one shuts it off.
BARTHOLDI AUTOMATIC BURNER.
Instead of a rotating stop-cock, as in other automatics, a gravity
valve is employed in the Bartholdi, which is held to its seat by the
weight of the armature and connecting stem, as shown in figure 17.
When the gas is turned off the valve rests upon its seat, as indicated
in the cut. By a closure of the electric circuit at the turn-on
button, two of the helices _M P_ are energized, causing the armature
_J_ to be lifted, thus, by means of the stem _H_, raising the valve
_G_ from its seat into the dotted position, and opening the gas way so
that the gas may issue to the tip, as shown by the arrows. At the same
time, the top of the valve strikes against the end of the lever _W_,
causing the circuit to be broken at the spark points _T U_,
resulting in a continuous sparking as long as the finger presses the
button. The magnet when raising the armature has also twisted or
partially revolved it, so as to bring the notch _d_ in the armature
over the end of the hook _e_, as shown in the dotted lines. When the
circuit is broken by lifting the finger from the button, the notch
falls into the hook and the valve is locked open.
[Illustration: FIG. 17.]
To extinguish the flame, the turn-off button is pressed, when a second
magnet (not shown in cut) lifts the armature and twists it in the
opposite direction, so that when the circuit is broken the armature
falls free to its normal position, closing the valve.
[Illustration: FIG. 18.]
THE ADVANCE AUTOMATIC.
This automatic burner, Fig. 18, is typical of the class having two
magnets, one to open valve and light gas, and another to close valve
and extinguish the light. It embodies an improvement over the older
types of burners in that the binding posts are mounted on a rubber
strip held by two screws, thus preventing the twisting and loosening
so common heretofore. It also allows of the valve being opened and gas
lighted by means of a match should the battery fail.
VIBRATOR BURNER.
This is an automatic burner which has no valve mechanism, but ignites
the gas only. It is generally placed in a cluster or ring where the
burners are close enough to light by contagion. It is much smaller in
diameter than the regular automatic burners, being but one and
three-quarter inches in diameter.
ARGAND AUTOMATIC BURNERS.
Automatic burners are also made for Argand, but present no radical
difference in construction over the regular type.
THE CONCEALED AUTOMATIC BURNER.
[Illustration: FIG. 19.]
This automatic, Fig. 19, consists of two iron-clad magnets, placed one
above the other, between which is located a gas valve. Through an
extension of the latter a pin is driven, one end acted upon by the
upper armature to open the valve and ignite the gas, the other by the
lower armature which serves to close the valve and extinguish the
flame. Around the burner is placed a porcelain candle slip of 3/4-inch
diameter and from 4-3/4 inches in length upwards.