US3533719A - Method of and means for igniting combustible mixtures - Google Patents

Description

METHOD OF AND MEANS FOR IGNITING COMBUSTIBLE MIXTURES Filed Nov. 21, 1967 Oct. 13, 1970 c, c, CQBARG ETAL 4. Sheets-Sheet 1 Oct. 13, 1970 c, QCOBARG ETAL 3,533,719 I METHOD OF AND MEANS FOR IGNITING COMBUSTIBLE MIXTURES Filed Nov. 21, 1967 v v 4Shet's-She'et 2 2 v Y ATLC .w lu usb W T 1 +5 Q Fig.3

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w/zmh v 71.4 Adams/ United States Patent Oifice 3,533,719 Patented Oct. 13, 1970 3,533,719 METHOD OF AND MEANS FOR IGNITING COMBUSTIBLE MIXTURES Claus C. Cobarg, Steinbach, and Hans W. Hofmann,

Wiesbaden, Germany, assignors to Braun Aktiengesellschaft, Frankfurt am Main, Germany, a corporation of Germany Filed Nov. 21, 1967, Ser. No. 684,795 Claims priority, applicatigg Ggrmany, Nov. 23, 1966,

Int. Cl. rzs 1/00 U.S. Cl. 431-267 2 Claims ABSTRACT OF THE DISCLOSURE The invention relates to the igniting of combustible mixtures, and relates more particularly to methods of and means for igniting in a combustible mixture that proceeds in a stream in a direction away from an exit nozzle of a conduit and is composed of at least one flowing substance such as fuel vapors, gases, dusts and fuel mists.

The ignition of mixtures of this type is a problem that has often occurred in the past, and many solutions have been proposed. For instance, electric sparks have been utilized for such ignition, which sparks were produced either by magnetic induction systems or by piezo electric crystals, sufiiciently close to the mixture for igniting it.

In other arrangements, the friction between a metallic body and a flint has been utilized to produce glowing particles which are directed into the mixture to ignite it.

Furthermore, electrically or catalytically heated filaments have become known, for igniting such mixtures.

Lastly, tinder-like materials have been heated by adiabatic compression of a gas mixture, for igniting a combustible mixture.

The proposals mentioned in the foregoing all have the drawback that additional physical effects are needed for producing localized elevated temperatures. In the case of the previously used adiphatic system, on the other hand, it is not possible to use it periodically; and furthermore it uses up too much tinder-like material.

Where the combustible mixtures are composed of at least one flowing substance of the aforementioned type and gaseous oxygen, the aforesaid drawbacks can be avoided.

It is accordingly among the principal objects of the invention to provide for the igniting of a combustible mixture, and yet to avoid the aforesaid drawbacks of the prior art.

It is a further object of the invention to provide for such igniting, that is safe, reliable, and relatively inexpensive.

Further objects and advantages of the invention will be set forth in part in the following specification and in part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof.

With the above and other objects of the invention in view, the invention consists in the novel methods, construction, arrangement and combination of various devices, elements and parts, as set forth in the claims hereof, certain embodiments of the same being illustrated in the accompanying drawings and described in the specification.

Briefly, the instant invention provides for igniting the combustible mixture of the aforesaid type by compressing a portion of at least said flowing substance adiabatically to a temperature sufficient for spontaneous ignition of the said portion, and directing the ignited portion into the main stream of the mixture of the flowing substance and gaseous oxygen. This offers the advantage to use the already existing gas-air-mixture, utilizing the chemical energy for the further heating. The instant invention thus dispenses with the need of any additional physical effect for the igniting of a combustible mixture.

The flowing substance flows, either before or after its admixture with gaseous oxygen in a conduit, and exits through a nozzle of the said conduit. In accordance with an embodiment, the mixture may be composed before the exiting through the nozzle, and a portion of the mixture may be separated from the remainder of the stream, compressed adiabatically to ignition, and thereafter the ignited portion returned to the remainder of the stream. This offers the advantage, for gas-fed burners, particularly lighters, of a simple construction, because, due to the formation of the mixture Within the conduit, a guiding away therefrom of the said portion to be ignited, is particularly simple and does not require any additional intake stroke. The formation of the mixture within the conduit may be accomplished by means of the well-known conventional injector principle.

The instant invention, however, is also usable where the mixture is formed only after the flowing substance or substances have passed through the exit nozzle, by admixing the substance or substances outside the conduit with air and hence with gaseous oxygen. A portion of the mixture may be taken into a compressor, then be compressed to self-ignition within the compressor, and subsequently be directed towards the remainder of the stream that proceeds in a direction away from the exit nozzle. This offers the advantage of independence of the substance used, and flowing substances may be fuel vapors and/or gases and/or dusts and mists which, when mixed with gaseous oxygen, form a combustible mixture.

It is possible to direct the ignited portion into the remainder of the stream in the direction of said remainder of the stream; for reasons of simplicity of construction, however, in accordance with a preferred embodiment the said ignited portion is directed towards the remainder of said stream transversely to the direction of said remainder of said stream, as thereby there is provided the shortest distance between the main stream of the mixture and the point of ignition.

For compressing the mixture, as indicated in the fore going, the instant invention provides for utilizing a com pressor. In accordance with a preferred embodiment, that compressor has a cylinder that defines an internal compression chamber in which there are opera'ble movable compression means that move within the chamber in one direction during its compression stroke. In accordance with the instant invention, it is possible to direct during its discharge from the chamber the said ignited portion in a direction transversely to the direction of the compression movement of said compression means; in accordance with a preferred embodiment, however, the ignited portion is discharged from the compression chamber in the direction of the compression movement of the compression means. In accordance with a preferred embodiment, furthermore, the compression chamber is so arranged that its discharge aperture for the ignited portion is generally within the region of the mixture stream proceeding from the nozzle of the conduit.

The compression cylinder may be arranged concentrically to the exit nozzle of the conduit, but for the sake of simplicity and efiiciency it is preferred to arrange the discharge aperture of the compression chamber at right angels to the direction of the mixture stream proceeding away from the exit nozzle of the conduit The compression chamber may be fed with a portion of the mixture that is produced in the conduit before its passage through the exit nozzle of the conduit. This arrangement is particularly suitable for flowing gases; in order to prevent the interruption of the main stream of the mixture by the removal therefrom of said portion to be ignited, it is advantageous to separate the said portion by means of a piston that forms a part of the aforesaid compression means; and to make this piston sufficiently thin as compared to the cross sectional area of the said conduit, and which piston is moved transversely to the flow direction within the conduit near the said piston.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary central sectional view of the conduit and exit nozzle as well as a compressor with a discharge aperture nozzle, in accordance with an embodiment of the invention;

FIG. 2 is a fragmentary central sectional view, similar to FIG. 1, but showing a modification in that the compression chamber intersects the conduit;

FIG. 3 is a fragmentary central sectional view, similar to FIG. 1, but embodying a modification;

FIG. 4 .is a fragmentary central sectional view similar to FIG. 2, but embodying a modified compression cylinder similar to that of FIG. 3;

FIG. 5 is a fragmentary central sectional detail view showing a modification;

FIG. 6 is a fragmentary sectional view, similar to FIG. 5, but embodying a further modification; and

FIG. 7 shows a complete gas lighter embodying the invention in a form similar to FIG. 2.

In carrying the invention into effect in the embodiments which have been selected for illustration in the accompanying drawings and for description in this specification, and referring now particularly to FIG. 1, there is provided a conduit that has an exit nozzle 1; at an angle to the conduit, there is arranged a compression cylinder 2 that defines an internal compression chamber 6 that has a discharge aperture or aperture nozzle 4, and wherein a piston 3 is reciprocable between opposite extreme positions a and b shown in FIG. 1.

At the beginning of the operation, the piston 3 is positioned close to the aperture 4 in the position a. During the intake stroke, the piston 3 is moved from the position a to the position b shown in FIG. 1, thereby taking in a portion of the stream of mixture that proceeds in the direction of the arrow (upwardly, FIG. 1) away from the exit nozzle 1.

The movements of the piston 3 may be controlled by well-known conventional means, such as a linkage or the like controlled either manually or automatically, as the situation may demand, in accordance with principles with which skilled artisans are fully familiar.

By a rapid movement in the direction of the arrow (pointing to the left, FIG. 1) by the piston 3, from the position b to the position a, the portion of the mixture that had been taken into the chamber 6 during the preceding intake stroke will be compressed adiabatically. Owing to this compression stroke by the piston 3, the temperature of the mixture will be raised, and after the temperature surpasses the self-ignition temperature of the mixture, the combustion of the mixture will commence. The hot gas will escape through the aperture 4, and will ignite the stream of the mixture that proceeds (upwardly, FIG. 1) from the exit nozzle 1. The discharge aperture 4 must be sufficiently small, so that during the compression stroke speed of the piston 3 the compression pressure suflicient for the spontaneous ignition of the portion in the chamber 6 will be reached. It is advantageous, by forming the edges of the aperture 4 as flowing edges, to increase the friction of the gases exhausted through the discharge aperture 4, and thereby to aid the heating of that portion.

In FIG. 2 there is shown an exemplification particularly suitable for the use in connection With fuel gases. The fuel gas flows in the conduit 7, and outside air enters through the mixture nozzle 5, thereby generating the gasair combustible mixture. The mixture will flow in the conduit 7, and will fill all the ducts connected with the conduit 7. As in this modification the compressor chamber 6 intercommunicates interiorly with, and intersects, the conduit 7, the combustible mixture will also penetrate into the compression chamber 6, as long as the piston 3 remains in its position (shown in FIG. 2) c. The piston 3 is movable in opposite directions (horizontally, FIG. 2) between one extreme position shown in FIG. 2 at c and, respectively, another extreme position at a.

After the chamber 6 has been filled with said mixture, the piston 3 will be moved into the chamber 6 (in a direction to the left, FIG. 2). In the position b, the piston 3 will close the compression chamber 6 against the conduit 7, and will compress the portion of the mixture that had previously been guided into the chamber 6. As the piston 3 continues past the position b to the position a, it will compress the portion of the mixture in the chamber 6. The portion will be self-ignited, and will be discharged through the discharge aperture 4 and will ignite the main stream.

The piston 3 should be suificiently thin, as compared to the width of the conduit at the intersection with the chamber 6, so as to avoid the interruption of the flow within the conduit 7.

In FIGS. 3 and 4 there are shown modifications involving the compression chamber 6. The exhaust aperture 4 no longer is in alignment with the central axis of the chamber 6, as had been shown in FIGS. 1 and 2, but instead is defined in a side wall of the cylinder 2 at a distance from the end Wall of the chamber 6 sufficient to create a pocket at the (upper, FIGS. 3, 4) section of the chaber 6 that is closed on all the sides except on the side of the piston 3, and which may be closed completely by the piston 3.

By this arrangement, the compression pressure within the cylinder 6 may be increased in a simple manner. The piston 3 is movable between two extreme positions at b and c, the latter representing the end of the compression stroke. In the beginning, the piston 3 will be positioned at a, and will then be moved to the position b for taking in a portion of the mixture from the main stream, through the aperture 4. During the subsequent compression stroke, the piston is moved from the position b to the position 0. As soon as the piston 3 passes during the compression stroke the aperture 4, the pocket of the compression chamber 6 will be closed and'the compression proceed without any escape of mixture from the pocket. Upon self-ignition of the portion of the mixture within the pocket, the ignited portion will push back the piston 3, and upon the clearing by the piston 3 of the aprture 4, the portion will exhausted through the aperture 4 and will ignite the main stream that proceeds from the exit nozzle 1.

In the modification of FIG. 4, the piston 3- initially stands in the position a permitting the chamber 6 to be filled with the mixture flowing in the conduit 7, similar to the arrangement of FIG. 2. Thereafter, the piston is driven during its compression stroke to the other extreme position d. As the piston 3 passes during the compression stroke the position b, it separates the chamber 6 from the conduit 7. Between the positions c and d, the piston 3 will compress substantially without any leakage the portion of the mixture remaining in the pocket of the chamber 6, until that portion is self-ignited. Thereafter, the piston 3 is returned and during its return stroke towards the position a clears the aperture 4 and permits the discharge of the ignited portion of the mixture through the aperture 4.

The arrangement of the pocket in the chamber 6, in accordance with FIGS. 3 and 4, permits the entrapment of the segregated portion and its substantially leak proof compression. This is in contrast to the embodiments of FIGS. 1 and 2, wherein leakage occurs through the discharge aperture 4 during the compression stroke. In order to avoid this loss in compression, valve means may be provided, as shown in FIGS. 5 and 6.

In the embodiment shown in FIG. 5, a valve 41 is provided that normally closes, under the bias of a leaf spring, the aperture 4 of the chamber 6 of the cylinder 2. The valve 41 acts to close the chamber 6 during the compression stroke of the piston 3. The pressure of the leaf spring is so adjusted that the valve 41 will yield after the portion in the chamber 6 has been ignited, thereby permitting the exhaust of the ignited portion through the aperture 4 opened by the valve 41.

In order to permit an intake stroke, as necessary in accordance with the embodiment of FIG. 1, the valve arrangement will need to provide for the admission of the portion through the aperture 4 into the chamber 6 during the intake stroke of the piston 3. Such an arrangement is shown in FIG. 6.

In accordance with the modification of FIG. 6, the aperture 4 is releasably closed by a valve 41, like in FIG. 5. Additionally, however, there is provided a flutter valve 43 and bores 44 that are provided in the end wall of the cylinder 2 adjacent the aperture 44. The flutter valve will close the bores 44 during the compression stroke of the piston 3, but will permit the entry through the bores 44 of the portion to be taken into the chamber 6 during the intake stroke of the piston 3. The flutter valve 43 is composed of flexible material permitting during the intake stroke of the piston 3 the entry of the portion through the bores 44, but closing the bores 44 during the compression stroke of the piston 3.

The arrangement of FIGS. 5 and 6 is possible because after the ignition the pressure within the chamber 6 increases to such an extent that the valve arrangement will provide for safe and releasable closing. It is furthermore advantageous to use the energy of the ignited portion for tensioning, for instance, of the valve spring of the valve 41.

In FIG. 7 an ignition device according to FIG. 2 is arranged inside a housing 11. By actuating a push button 10 a lever 12 is moved downwards. During this movement at first a fuel valve '8 which comprises a pressure reducing means of any well known construction is opened by an elastic connection 19. At the same time a spring 16, connected to piston 3 through shaft 18 and supported by support 17 is loaded through latch 15. At the end of the movement piston 3 is set free because lever 12, pivoting about pin 13 releases latch 15 automatically since the eflective distance between pin 13 and latch holding opening 14 is shortened by the rotation of the lever 12. The force exerted by spring 16 to piston 3 is driving the piston 3 with high speed into cylinder 2. The gaseous mixture which is ignited inside cylinder 2 is then pressed through discharge aperture 4 and ignites the main stream of the combustible substance which is flowing from reservoir 9 through conduit 7, exit nozzle 1, and flame opening 20 and which was mixed with air at mixing nozzle 5.

We Wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent is as follows:

1. An apparatus, for use in igniting a combustible mixture composed of at least one flowing substance and gaseous oxygen, comprising in combination, a conduit structure establishing a conduit for conducting at least said substance and having a nozzle for the exit from said conduit, said mixture proceeding away from said nozzle in a stream in a direction, a compressor defining a compression chamber adjacent said nozzle and having an aperture near said stream, and compression means movable in said chamber, said chamber being operable to receive a portion of at least said substance, said compression means being operative to compress the taken-in portion to a temperature suflicient for spontaneous ignition thereof, said ignited portion being discharged from said chamber through said aperture into said stream, said mixture flowing through said conduit and nozzle, said conduit intercommunicating interiorly with said chamber, whereby a portion of said mixture will be guided from said conduit upstream of said nozzle into said chamber, said compression means being operative for subsequently compressing said portion in said chamber to said temperature, said ignited portion being thereafter discharged from said chamber through said aperture into said stream, said chamber intersecting said conduit, said compression means including a piston movable in said chamber at an angle to the direction of said conduit at said intersection, said piston prior to the compression action being positioned out of said chamber and in said conduit and being sufficiently thin so as to refrain from interrupting the flow within said conduit.

2. An apparatus, for use in igniting a combustible mixture composed of at least one flowing substance and gaseous oxygen, comprising in combination, a conduit structure establishing a conduit for conducting at least said substance and having a nozzle for the exit from said conduit, said mixture proceeding away from said nozzle in a stream in a direction, a compressor defining a compression chamber adjacent said nozzle and having an aperture near said stream, and compression means movable in said chamber, said chamber being operable to receive a portion of at least said substance, said compression means being operative to compress the taken-in portion to a temperature sufficient for spontaneous ignition thereof, said ignited portion being discharged from said chamber through said aperture into said stream, said compressor being independent of said conduit and taking in a portion of said mixture at a point downstream of said nozzle.

References Cited UNITED STATES PATENTS 312,805 2/1885 Browne 43 1268 1,323,139 11/1919 Woods 123143 1,463,751 7/ 1923 Powell 431--267 1,088,320 2/1914 Butler 431-268 FREDERICK L. MATTESON, JR., Primary Examiner H. B. RAMEY, Assistant Examiner

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