US2517782A - Flash tube for ignition of gas burners - Google Patents

Description

Aug, 8, 1950 F. A. GAUGER 2,517,782

FLASH TUBE FOR IGNITION OF GAS BURNERS Filed Feb. 5, 1944 INVENTOR. fP/r/v/r A 6/41/66? BY w my Patented Aug. g, 1950 2,517,782 FLASH TUBE FOR IGNITION OF GAS RN ERS Frank A. Qauger, Milwaukee, Wis. Application February 5, 1944, Serial No. 521,201

2 Claims. (Cl. 158-115) This invention relates to automatic lighting means for gas burners, particularly ior oven burners.

In gas stoves of the type generally known as the table top type the oven burner is located below and laterally of the constantly burning pilot light. In these constructions considerable difllculty has been experienced in causing an igniting flame to travel downwardly, or laterally and downwardly from the constantly burning pilot light to the oven burner. There is a tendency for a cloud of water vapor to form in the downwardly extending flashback tube and effectively block the subsequent propagation of the flame after an initial operation. In addition to the above, great dimculty is occasioned due to the fact that as the flashback tube heats up during operation of the oven, the stack velocity in the downwardly extending flame conducting pipe increases materially and frequently attains such a value that downward propagation of the flame is impossible. In addition to these defects, it has been found that there is considerable condensation resulting in dripping from the flashback tubes in the heretofore known devices.

This invention is designed to provide means for igniting an oven burner which is located below and usually laterally Of a constantly burning pilot light, such ignition means being so arranged that thereis no interference with ignition although the downwardly extending flashback tube is heated during the operation of the burner, in which there is no possibility of a cloudof water vapor forming in the flashback tube and preventing downward propagation of the name, and in which there is no condensation or dripping of moisture from the flashback tube.

Further objects are to provide a novel construction of a downwardly extending flashback or flame conducting tube, which is so arranged that although the tube becomes heated during the operation of the burner the stack velocity for the combustible mixture does not attain such speed as to prevent downward propagation of the flame. in which means are provided for maintaining communication between the inside of the tube and the outside air, such means extending longitudinally of the tube and being so designed as to maintain a continuous and unbroken column of combustible mixture within the tube from the lower to the upper end thereof prior to ignition, and being so arranged as to prevent a violent explosive action when ignition takes place.

Embodiments of the invention are shown-in the accompanying drawings, in which:

Figure 1 is an elevation partly broken away and partly in section, of the ignition means.

Figure 2 is a side elevation, partly in section and partly broken away, looking at the left upper portion of Figure 1.

Figure 3 is a. sectional view on the line 33 of Figure 2.

Figure 4 is a sectional view on the line 4-4 01' Figure 1.

Figure 5 is a sectional Figure 1.

Figure 6 is a sectional Figure 1.

Figure 7 is a sectional view corresponding to Figure 6 showing a modified form of construction.

In describing this'invention it is to be understood that an oven regulator, not shown, is so arranged that a manually opened valve, which is not automatically controlled, turns on a supply of gas to the pipe i3, see Figures 1 and 4, which pipe supplies a subburner and an extension burner hereinafter described. A part of the oven burner is indicated at 3 in Figure 1 and an extension of the oven Figures 1, 4, and 5. p

The pipe l3 leads to a sub-burner indicated generally by the reference character It, see Figure 1, and supplies such sub-burner through an adjustable Bunsen mixer indicated at IS. The

view on the line 5-5 of view on the line 8-6 of sub-burner is located at the bottom. of a downwardly extending flame conducting tube indicated generally by the reference character It. This downwardly extending tube terminates at its lower end in an upwardly converging conical hollow member II which is adapted to collect the combustible mixture from the sub-burner l4 and to lead such mixture into the tube It. The upper end of the tube extends into a fitting l8 which has a laterally extending outlet portion l9, such portion being preferably slightly turned downwardlypn its upper side as shown most clearly in Figure 3. The fitting I8 is rigid with an extension burner 20 which is supplied with a combustible. mixture through the pipe 2| communicating with the interior of the sub-burner M, as shown'in Figure 3. a The extension burner 20 projects the combustible mixture into a laterally extending flame conducting pipe 22 which is seated within a portion of the fitting l8 and also seated within the housing surrounding a constantly burning pilot light, not shown. a i

It is to be noted particularly from Figures 6 and 7 that the sub-burner I4 is provided with a U-shaped extension 23 which is in lighting relation with the oven burner 3 by means of the exburner is indicated at 1 in tension 1 of the oven burner. It is to be noted also that an intermediate portion of the extension 23 of the sub-burner I4 is in lighting relation with the extension I of the oven burner and that the extreme end of extension 23 of the sub-burner is adapted to heat one end of a thermocouple 24. The reason for having the thermocouple at the extreme end of the extension 23 is to insure that the combustible mixture is lighted throughout the entire extent of the extension 23 to insure lighting of the oven burner. The thermocouple 24 is connected by means indicated at 25 in Figure 5 with control means, not shown.

The gas from the pipe l3 passes through the Bunsen mixer l5 and supplies a combustible mixture to the sub-burner i4 and its extension 23 and also supplies combustible mixture to the extension burner 20. The sub-burner charges the downwardly extending tube IS with a combustible mixture and the extension burner 20 charges the laterally extending tube 22 with a combustible mixture. The combusttble mixture in the laterally extending tube 22 is ignited from a constantly burning pilot light, not shown, and the extension burner 20 is, therefore, lighted. It is to be noted that the slightly downwardly extending opening I! projects the combustible mixture from the upper end of the downwardly extending pipe I6 into proximity to the extension burner 20 and consequently such combustible mixture is ignited and the flame travels down the tube It and lights the sub-burner H, the extension 23 also lighting. Subsequently gas in allowed to pass to the oven burner 3 by means not shown. The oven burner is in lighting relation to the extension 23 by means of its extension I and consequently the oven burner is lighted from the sub-burner.

In order to carry the flame downwardly of the downwardly extending pipe l8, such pipe is made in a peculiar manner. It is so made that a continuous unbroken column of combustible mixture extends from its lower to its upper end prior to ignition and also is maintained prior to ignition independently of the temperature of the tube I8 and consequently independently of the stack velocity. This is accomplished in several different ways. a few of which have been shown. It is to be noted from an examination of Figures 1 and 6 that the tube It consists of an outer tube 63 and an inner tube 64, the marginal edges of the outer tube 63 overlapping the marginal edges of the inner tube 64 and such tubes being turned in opposite directions and being arranged in nested relation. Each of these tubes has a widely open section extending longitudinally thereof which open section is spanned by the other of the tubes. It is to be noted that the tube 63 has outwardly extending edges that overlap or overhang the tube 64 and that the tube 64 has inwardly overlapping or overhanging edges which extend inwardly of the tube 83. This provides restricted vent spaces 65 on opposite sides which when the stack velocity is rapid allows the entrance of outside air, but this air is so directed that it causes a combustible column of mixture to be maintained within the composite tube It and does not cause intimate comming-ling of the outside air with all portions of the combustible mixture in the tube It. Instead it has been found that a continuous column of combustible mixture extends from the bottom to the upper end of the downwardly extending tube II. It is to be noted that the stack velocity even when the tube is hot is not such as to prevent the downward propagation of the flame. A deflnite predetermined quantity of combustible mixture passes through the Venturi like or funnel like member i1 into the tube I6. The suction immediately above this member I'I produced by the heated tube II is broken, so to speak, as the side slots begin immediately above the member l1. Also at all points along the tube IS the suction, and consequently the stack velocity, cannot increase above the desired limit as outside air is immediately drawn through the longitudinally extending slots 65 and consequently great suction is not exerted on the continuous column of combustible mixture carried within the composite tube l8 and consequently the stack velocity never exceeds the right value to insure downward propagation of the flame.

Instead of following the construction shown in Figure 6 other constructions may be employed. For example, as shown in Figure 7, the tube It is formed of spiral shape and has overlapping marginal edges one of which is directed outwardly and the other of which is directed inwardly of the tube. These marginal portions overlap a slightly greater amount than the overlap shown in Figure 6 and provide a. longitudinally extending slot 88.

It is to be noted that with this type of tube the outside air that is drawn in serves to spin the mixture within the tube l6 and inasmuch as the combustible mixture is of less specific gravity than the incoming air, it will be maintained in a solid unbroken column centrally of the tube It and the heavier incoming air will rotate externally of this unbroken column of combustible mixture.

While preferred constructions of the downwardly extending tube have been shown, it is to be distinctly understood that modifications could be made without departing from the spirit of this invention. For example instead of using the sheet metal type of tubes described, the tubes could be formed of cast metal provided the tubes had the characteristics hereinabove set forth. It is also apparent that the slot or slots extending longitudinally of the tube need not be continuous. They could be formed by a series of openings provided the characteristics hereinabove set forth were maintained. From actual observation of this apparatus while it is in operation, it has been found that there is a trailing flame on the outer side of the tube It as well as the propagation of the flame downwardly interiorly of the tube l6. This trailing flame externally of the tube is most pronounced when the device is cold and is operated for the first time. As the device heats up, the outside trailing flame becomes less and less prominent.

Another advantage which results from this construction is that the explosion within the downwardly extending tube is softened up, so to speak, and is not a violent cannon like blast. Instead it has only a very small explosive efiect making at most a very slight sound.

It will be seen that means have been provided by this invention for lighting a burner which is spaced downwardly and perhaps laterally of a constantly burning pilot light, and that this means is so constructed that prior to ignition it provides a continuous column of a combustible mixture from the lower to the upper end of the downwardly extending tube and maintains this column of combustible mixture in unbroken continuity irrespective of stack velocity or temperature of the downwardly extending tube and also prevents excessive stack velocity which would preclude the possibility of downward propagation of the flame.

It is to be noted also that the free venting of the tube insures the discharge of any cloud of water vapor that might act as a plug to prevent subsequent ignition. Also it is to be noted that condensation is prevented within either the downwardly extending tube I6 or the laterally extending tube 22. The downwardly extending tube is heated at its lower end from the subburner l4 and at its upper end from the extension burner 20 and is maintained at a temperature above that at which the condensation would occur at all points along its length. Also the tube 22 is heated at one endfrom the extension burner 20 and at its other end from a constantly burning pilot light. Consequently no condensation can occur at any point along its length as all portions of this tube are maintained at a temperature above that at which condensation would occur.

It will be seen further that this invention provides a construction which is eminently practical and is easy to construct and is not dependent upon delicate and easily damaged parts and is foolproof.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. Ignition apparatus for causing the downward propagation of an igniting flame comprising a downwardly extending tube having an upper and a lower opening, a burner adjacent the lower opening for feeding a combustible mixture into said tube, said tube having a longitudinally extending slot formed by overlapping radially spaced walls, and means adjacent the upper end of said tube for igniting the column of combustible mixture to thereby cause downward propagation of the flame and lighting of said burner.

2. Ignition apparatus for causing the downward propagation of an igniting flame comprising a downwardly extending tube having an upper and a lower opening, a burner adjacent the lower opening for feeding a combustible mixture into said tube, said tube being formed of sheet material having longitudinally extending, spaced, marginal portions with the edge of one marginal portion spaced inwardly of the other along the radius of the tube to provide a longitudinal slot with overlapping spaced walls arranged to provide an arcuate longitudinally extending passage for the admission of outside .air between said walls, and means adjacent the upper end of said tube for igniting the column of combustible mix ture to thereby cause downwardpropagation of the flame and lighting of said burner.

FRANK A. GAUGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 413,809 Marsh Oct. 29, 1839 1,747,015 Leins Feb. 11, 1930 1,991,609 Furlong Feb. 19, 1935 2,048,065 Gauger July 21, 1936 ,072,552 Gauger Mar. 2, 1937 2,087,433 Hollman July 20, 1937 2,268,959 Ray Jan. 6, 1942 2,273,127 McGoldrich Feb. 17, 1942 2,303,672 Wantz Dec. 1, 1942 2,315,773 Couzens Apr. 6, 1943 2,334,603 Brumbaugh et a1. Nov. 16, 1943 2,351,277 Mantz June 13, 1944 2,353,042 Koch July 4, 1944 FOREIGN PATENTS Number Country Date 701,131 France Aug. 4, 1930 827,388 France Oct. 1, 1937

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