CHAPTER II.

MULTIPLE GAS LIGHTING.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.