US1118942A - Ignition device. - Google Patents

Description

IGNITVION DEVIGE. APPLIUATIOE FILED 00T. 7, 1910. 1,1 18,942. Patented Dec. 1, 1914 y. l w 7 H, ,y J M 5 Wiz f UNITED STATES PATENT A OFFICE.

HOWARI) LYON, 0F GLOUCESTER CITY, NEW JERSEYXASSIGNOR TO WE'LSBACH LIGHT COMPANY, A. CORPORATION 0F NEW JERSEY,

IGNITION DEVICE.

Specilloation o! Letters Patent.

Application led october 7, 1910. Serial No. 585,772.

To all Ywhom, t may concern Be it known that I, HOWARD LYON, a citizen of the United States, and a resident of Gloucester Cit in'the county of Camden and State of lNew Jersey, have invented certain new and useful Improvements in Ignition Devices, of which the following is a description.

My invention relates to electrical ignition devices for gas burners and has for its object the production of an igniting filament of improved form, capable of better withstanding the effects of the high temperatures to which such filaments are subjected.

. As is well known, such filaments are usually composed of platinum or an alloy of platinum, and in order to secure a hi h resistance and a concentrated heating e ect with a minimum of current, it is usual to make the filament of extremely minute cross section. Such material when warmed 'by an electric current in the presence of an explosive mixture of lgas and air is acted upon catalytically and eated to an extremely high temperature by chemical action. This high temperature tends to melt and destroy the llament.

It is hi hly desirable that the ignition device sha be capable of operation when subjected to the current from a single dry cell. In order that this may be accomlished it is necessary to concentrate the eating elect as much as possible b reducing the' cross section of the igniting filament. Such reduction of course increases its resistance and thereby determines the length of lilament that can be used, that is, the filament cannot exceed a certain length in order that its resistance may be kept down to allow the assage of a current of sulioient strength ireferabl7 from a sinle cell) to cause ignition. T ese extremely gine filaments are usuallysoldered at their ends to suitable conductors, such as leading in wires, for applyin the current thereto. Such conductors ein of comparatively great cross section an large heat capacity necessarily abstract heat from the filament and rapidly cool the ends thereof, so that in case the filament extends 1n a straight line from one lead to the other, the only ortion of the filament which is eil'ective or initiating the catal 'e action of the' gas is av very short lengt thereof situated midway between its ends which I term the effective portion. This effective ortion is at all times the hottest part of t e lilament and the most likely to be consumed or fused during ignition, so that such laments almost invariably give Way at this point. The ignition filament also parts with heat by radiation and by convection of the surrounding gas which take lace in all directions. The fact that the Elament, the mass of which is almost inappreciable, is necessarily in close proximity to the leading in w1res whose mass is comparatively very great and usuall also to the metal forming the body of the igniter, all of which is at a low temperature, means relatively great heat losses which are subtracted from the effectiveness of the `igniting current. These radiation and convection losses are proportionately less in a filament' formed as a s iral or helix than in one formed as a straig t line, for the reason that adjacent coils of the helix protect or blanket each other, and 1t has been proposed heretofore to form the filament as a helix. This form, however, is open to the objection that it either increases the length of the filament, thereby increasing its resistance and necessitating an increase in the battery voltage, or else it means that the distance between the leading in wires or conductors must be decreased which brings them closer to the central or e'ective portion of the filament which increases the heat losses thereof.

I have discovered that the most effective and ellicient form for the filament is that of a partial spiral or helix, that is a filament.

having straight ends and a loop or helix therebetween. It is an advantage for such helix to have more than one convolution in order to obtain the blanketing ell'ecft of one coil upon its neighbor, but the helix should not have too many convolutions as this necessitates bringing the leading in wires too close to the effective portionl of the lilam'ent. I prefer therefore to. form the helix with only two or three convolutions. I have obtained excellent results with a filament of this form. The effective portion of the lilament seems to be protected in some wa by the gas within the helix; perhaps the sudden expansion thereof when ignition occurs causes it to convectively remove-heat units from the effective or hot portion of the filament and further the gas within the helix by its expansion pushes away the hot products of "combustion after an ignition.

In order that the invention may be more clearly understood, reference is hereby made to the accompanying drawing, in which- Fi 1 is a side elevation `of an inverted gas urner provided with an ignter consti-noted in accordance with my invention; Fig. 2 is an enlaged detail section of lthe igniter shown in ig. 1 and Fi 3 is a section on line 3-3 of Fig. 2. ig. 4 is a greatl ma ed side view ofthe filament, andy ig. 5 is a similar view of amodifica1 tion.

Thel comprises a tubular body 1, prefera y of brass, secured by a set screw 2 upon a mpple 3 riveted to the canopy 4 of the burner. A baille plate 5 extends-across the bore of the tube `1 and oppositely dissel posed windows 6 are 'formed in the walls of said tube above the baille plate. 'Iohe filament 7 consisting 4of a wire of platinum or platinum alloy is formed as shown in Fig. 4 with a central spiral or helix 8 consisting of as two convolutions and straight ends 9 extendoutwardly therefrom. The ends of the ent are soldered to the leading in wires 1Q and 11 and the axis of the helix is at right angles to a straillit line drawn from one extret'nity ofthe ament to the other. The wire 10 is electrically connected to a metallic sleeve-12. held by a set screw 13 and the -wire 11 is similarly connected to a metallic bolt 1.@ carried vby the insulator 15 which is set i6 in the sleeve ,12, A metal block 16 is threaded on the bolt 14 and has a bore 1J? and binding screw I8 for holding the hne wire 19 which leads to one side of the battery, the electrical circuit being com leted through the fixture and gas pipe 20. e ilamentis protected against excessive tem rature duriliggnition by reason of the act thatthe plate 5 ermits only a small rcentagc of the ascen 'gasto approach thelament, and at the same time atmospheric air ispermittedtoenterfreel througtheinlets or windows 6. The e ectof 's structure is to produce in the immediate vicinity of the filament an iitible mixture of minimum richness, so at the heat due to combustion will be a In operating the apparatus' with one cell the temperature produced in the fila.-A ment will be such as to initiate'catalytic acle tion of the gas,.which.rapid1 increases its temperature to that requi for ignition. The temperature produced by the electric current of itself is preferably insuiicient to canse ignition. The amount of current regq t o initiate catalytic action viii-a wire ormed mtoatwo or three turn spiral at-the center is appreciabl less than for: the same wire na to? of 11:: hea;

co e o e a )neemt i ps o u the slim i i The advantages of'my invention may be obtained in a somewhat imperfect manner by replacing the Vspiral" or helix ofthe iila ment y a zigzag' arrangement as shown in Fi 5, 91 by any other arran ment by which different parts of the effective portion of the filament extend side by side so as to blanket each other.

While `I haveshqwn the improved filament mounted in a tube and protected against excessive temperature duri ignition by abailie plate and windows, t e said filament may be mounted and-protected in other ways which will be obvious to anyone skilled in theart. i l f i Having now described my invention,- what Iclaimis: W y

1f In an electrical ignition device, .fila- 'ment supporting conductors and a platinum containing filament of minute cross section the central portion `of which is so formed that different arts extend side by side so as to blanket eac other, and its ends extend therefrom to said supporting conductors to which they are secur whereby the length of the filament and its resistance are mini-- mized and excessive losses of heat are avoided, and means for protecting said filament a inst excessive temperatures during ignition, said means comprisinga bae between said central portion of said filament and.

the source of gasto be ignited and an air inlet adjacent said iilament, substantially asset forth.

2. In an electrical ignition device, a conductive filament having its central portion formed asl a helix and ends of. substantial len "h extending therefrom, the axis of said helix extending transversely to a strai ht line drawn from one extremity yof the nient to the other, and a balile between saidI helix and the source of gas to be 3. In an electrical igmtion device,;a conductive filament of minute cross section hayingits effective portion'formed of arts extending side by side so as to bla et each other, and ends extending therefrom for a substantial distance, whereby heatlosses in said effective rtion are minimized, and means comprising a baille between said lilament and the supply and an air inlet adjacent the ament for protecting 'said filament against excessive temperatures duringi ition, substantially as'set forth;

'- 4. an electrical ignition device, a conductive Afilament having an effective portionA formed `with one or more convolution's and ends of substantial .len Ah extending therefrom in substantially irect lines to their points of support, and a baie Asituated beA tween said e ective portion and the source of gas to be ignited. T

5. In an electrical ignition device, a conductive filament having ran efectivo portion formed with encor-more controlutions and ends of substantial length extending therefrom in substantially direct lines to their points of support, a baie situated between said effectixe portion and the source of gas to be ignited. and one or more apertures adjacent said filament for admitting atmospheric air into proximity thereto.

6. In an electrical ignition device, `la ment supporting conductors, and a conductive lilament of minute cross section the central portion of which is so formed that dif Vferent parts extend side by side so as to blanket each other, and its ends extend therefrom in substantially direct lines to said supporting conductors to which they are secured, the length of said ends being suicient to revent the central portion from being chilled by the proximity of said supporting conductors, and means for protecting said filament against excessive temperatures during ignition, said means comprising a baille between the central portion of the filament and the source of gas to be ignited and an air inlet adjacent said central portion, substantially as described.

This specification signed and witnessed this 5 day of October 1910.

HOWARD LYON.

Witnesses:

JOSEPH H. JOHNSON, A. G. HENsEL. Jr.

Correction in Letters Patent No.1,1418,942.

ends of substantial length extending therefrom in substantially direct lines to their points of support, a baille situated between said eilectiif'e portion and the source of gas to be ignited, and one vor more apertures adjacent said filament for admitting atmospheric air into proximity thereto. n

6. In an electrical ignition device, 'lilament supporting conductors, and a conductive filament of minute cross section the central portion of which is so formed that different parts extend side by side so as to blanket each other, and its ends extend therefrom in substantially direct lines to said supporting conductors to which they are secured, the length of said ends being` J an improvement in- HOWARD LYON.

Witnesses JOSEPH H. JOHNSON, y A. G. HENSEL. Jr.

'It is hereby certified that in Letters' Patent No. l,ll`8,9l2, grantedI December 1. Inl-l, upon the application o1 Howard-Lyon, of Gloucester City, New Jersey, forl Ignition [1)evices," an error appears in the printed sp'eciticationI requiring correction as follows: `Page il, line t3, for the, word line" read time; and that the said Letters Patent should be read with thscorrection therein that the sinne may conform to the record of the case in the Patent Olice. I

Signed and sealed this 12th day oi' January, A. D., 1915.

R. F. WHITEHEAD,

Acting Commissioner f Patents.

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