US3523747A - Gas burner ignition - Google Patents

Description

Aug. 21, 1970 W GROSS ETAL 3,523,741]

GAS BURNER IGNITION Filed June 18, 1968 INVENTORS: GILBERT w. GROSS I LEONARD H. MICHAELS 42 WILLIAM H..PATRICK United States Patent 3,523,747 GAS BURNER IGNITION Gilbert W. Gross, Elmhurst, Leonard H. Michaels, La

Grange, and William H. Patrick, Downers Grove, Ill.,

assignors to Harper-Wyman Company, Hinsdale, 11].,

a corporation of Illinois Filed June 18, 1968, Ser. No. 737,898- Int. Cl. F24c 3/10 US. Cl. 431-192 7 Claims ABSTRACT OF THE DISCLOSURE A spark ignition device is located between flash tubes extending to space gas burners. A spark gap is disposed in a small diameter neck of a passageway extending through the body of the device between the flash tubes. Outwardly flared, funnel-shaped portions extend from the neck to the mouths of the passageway. Ramp surfaces guide flow from the flash tubes upwardly to the spark gap. Direct, straight line flow between the flash tubes is substantially obstructed.

The present invention relates to gas burner ignition, and more particularly to improved apparatus for flash tube ignition of spaced burners such as range top burners.

Flash tube arrangements have long been used automatically ot ignite range top and other burners from a continuous ignition source such as a standing pilot. In a typical system, one or more burners each have a lighter port or jet receiving a combustible mixture of gas and air from the burner inlet. When the burner is turned on, the mixture emerges from the burner ports and also is expelled from the lighter port or jet and into a flash tube. The flash tube extends to the region of a standing pilot burner, and when the combustible mixture reaches the pilot burner it is ignited, and a flashback or controlled explosion takes place in order to ignite the gas flowing from the burner ports.

In order to avoid the gas consumption and heat production incident to the use of standing pilot burners, it has been proposed to provide flash tube systems using spark electrodes in place of a standing pilot for lighting the air-gas mixture emerging from the flash tubes. However, difliculties have been encountered in this approach and particularly in igniting a second burner when a first burner served by the same spark electrodes is operating. One problem is that the second burner may fail entirely to ignite due to lack of a proper combustible atmosphere at the spark gap. Another problem is that upon ignition of the second burner, a concussion wave may be created which extinguishes the lighter port or jet of the first burner.

Accordingly, it is an object of the present invention to provide improvements in gas burner ignition apparatus and methods, and to overcome the disadvantages of known arrangements.

Another object of the invention is to provide an improved spark ignition device.

A further object is to provide a spark ignition apparatus capable of consistently lighting one burner when another burner is operating without extinguishing the lighter port or lighter jet of the previously ignited burner.

Another object is to provide spark ignition apparatus of simplified and inexpensive construction.

A further object is to provide a spark ignition device wherein the spark gap is protected from becoming fouled by food drippings and the like.

Another object is to provide improved apparatus for ice guiding an air-gas mixture from a flash tube to a spark gap for ignition.

In brief, the above and other objects of the present invention are realized in one embodiment of the invention by a spark ignition apparatus serving to light spaced gas burners such as range top burners. A novel spark ignition device is located between the burners and communicates with lighter ports of the burners by means of flash tubes. When either burner is turned on, the sparking device is actuated to produce intermittent ignition sparks, while a combustible air-gas mixture from the burner flows through the flash tube to the device, where it is ignited and flashes back to ignite the burner ports. The spark ignition device includes novel structure for reliably igniting one burner even if another burner is already burning, and for accomplishing such ignition without extinguishing the lighter port of the previously ignited burner. The device includes a body or housing formed of electrically insulating and heat resistant material supporting a pair of spark electrodes. The body includes a passageway extending through the body and between the ends of the flash tubes for conducting flow from the flash tubes to the spark electrodes. The spark gap, located in the passageway, is protected from becoming fouled by food drippings, spills or the like.

In accordance With important aspects of the invention, the passageway includes a narrow neck portion sandwiched between outwardly flaring portions, and the spark gap is located in the neck portion. The walls of the passageway form a flow guiding surface including a flow obstruction portion located between the flash ignition tubes and blocking off a substantial portion of the path of direct flow between the tubes. The guiding surface also includes generally upwardly inclined ramp surfaces for guiding flow entering the passageway in an upward direction toward the spark gap.

The invention and its objects and advantages may be better understood from consideration of the following detailed description of one embodiment of the invention illustrated in the accompanying drawing in which:

FIG. 1 is a largely diagrammatic, side view of a gas burner ignition apparatus including a spark ignition device constructed in accordance with the invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a sectional view taken along the line 44 of FIG. 2; and

FIG. 5 is a sectional view taken along the line 55 of FIG. 2.

Referring now to the drawing, there is illustrated a gas burner ignition apparatus designated as a whole by the reference numeral 10 and constructed in accordance with the principles of the present invention. The apparatus 10 serves automatically to accomplish the ignition of fuel at a spaced pair of gas burners 12 and 14, which may for example be range top burners associated with a gas range not otherwise illustrated. In accordance with important features of the present invention, the apparatus 10 includes a novel and improved spark ignition device generally designated at 16 communicating with the burners 12 and 14 by way of flash tubes 18 and 20.

The operation of this general class of apparatus is well known to those skilled in the art. Each burner 12 and 14 includes burner ports 22 and 24, respectively, as well as a lighter port 26 and 28, respectively, and both the burner ports and the lighter ports communicate with the inlet of the corresponding burner. Although a simple lighter port arrangement has been illustrated, more sophisticated systems including one or more lighter jets could also be used in connection with the invention. In the illustrated arrangement, when one of the burners is turned on, a combustible air-gas mixture is admitted to the burner and emerges from both the burner ports and the lighter port. The air-gas mixture from the lighter port flows through the respective flash tube 18 or 20 to the spark ignition device 16. Suitable circuitry, of any type well known to those skilled in the art, is provided for operating the spark ignition device 16 whenever one of the burners 12 and 14 is turned on. When the combustible air-gas mixture from one of the burner ports 22 or 24 reaches the spark ignition device 16, it is ignited and a controlled explosion or flashback takes place. The flashback serves to ignite the respective lighter port 26 or 28 and thereby to ignite the burner ports 22 or 24.

In arrangements of this general type which have been used in the past, problems have been encountered in consistently and reliably igniting the burners. The most serious problems occur when one of the burners has been previously ignited and is in operation, and an attempt is made to ignite the second burner. One difliculty is that the spark ignition device fails to produce ignition of the second burner. It is believed that this difliculty may be caused by the fact that combustion products from the lighter port of the previously ignited burner travel through the corresponding flash tube to the spark ignition device and smother the spark.

Another type of problem is that even though the second burner is ignited, the concussion wave produced by the ignition flashback extinguishes the lighter port of the first ignited burner. When this occurs, the air-gas mixture from the extinguished lighter port may again travel to the sparking device and be ignited, thereby causing extinguishment of the lighter port of the second burner. An undesirable reciprocating or ping-pong effect accompanied by a popping noise may result. It is believed that this problem may be due, at least in part, to the fact that a spark ignition device necessarily operates intermittently rather than continuously as does a pilot burner. For example, known spark devices may produce ignition sparks at a rate in the neighborhood of one or two a second or so, rather than continuously. As a result, it may happen that the air-gas mixture is not ignited immediately upon reaching the spark gap, and an excess amount of the combustible mixture may collect in the neighborhood of the spark gap or may travel beyond the spark gap prior to the occurrence of a spark. It is believed that this may increase the severity of the flashback explosion and produce a concussion wave which extinguishes the other lighter port.

Since both of these problems are highely undesirable, attempts have been made to overcome them in the design of known ignition apparatus. It has been found that with a trial and error process these problems can be greatly reduced for any particular arrangement by careful design of the burner, the flash tubes, and the sparking device as well as their relative positions. However, the difliculty with this approach is that a different apparatus must be developed for each different type of burner and flash tube arrangement, and it has not been possible to provide a standard spark ignition device which reduces these problems to an acceptable level for many types of range configurations.

In accordance with an important aspect of the present invention, the novel spark ignition device 16 is constructed and designed so that it can be conveniently used in place of a standing pilot in many standard types of gas ranges. The device is effective to minimize the problem of ignition failure and lighter port extinguishment regardless of the particular configuration of the burner and flash tube constructions.

More specifically, and referring now more particularly to FIGS. 2-5, the novel spark ignition device 16 provided in accordance with the present invention includes a body 30 formed of a suitable heat resistant and electrically insulating material such as a ceramic or the like. Conveniently, the body may be formed in two halves joined together by rivets 32. A pair of spark electrodes 34 and 36 forming a spark gap generally designated as 38 are sandwiched between the halves of the body 30. The electrodes are supported by means of a pair of electrode bushing assemblies 40, and each is connected to a conductor 42. The conductors 42 are connected to suitable well known circuitry for producing sparks at the spark gap 38 either one of the burners 12 and 14 is turned on.

In order to guide a flow of combustible air-gas mixture from either of the flash tubes 18 and 20 to the spark gap 38, the body 30 includes a passageway 44 extending between opposite sides thereof. The opposite ends or mouths 44a of the passageway are located adjacent the ends of the flash tubes 18 and 20 whereby material flowing from the flash tubes enters the passageway 44. One advantage of this construction is that the spark gap 38 is protected by the body 30, and is not subject to becoming fouled by foods and liquids which may spill over into the region of the device 16.

In accordance with one feature of the invention, the passageway 44 includes a central neck portion 44b having a cross-sectional area equal to the smallest cross-sectional area of the passageway. Furthermore, the neck portion 44b is communicated with the ends 44a of the passageway by outwardly flaring portions 44c. As a result, when the combustible air-gas mixture from a flash tube enters one of the mouths 44a of the passageway 44, it flows through one of the generally funnel-shaped flared portions 44c to the neck portion 44b where it comes in contact with the spark gap 38. It is believed that one advantage of this construction is that the volume of combustible mixture which can collect in the immediate vicinity of the spark gap 38 is limited. In addition, upon combustion of the airgas mixture by a spark at the gap 38, the explosion or concussion force moves from the small cross-sectional area neck portion 44b through the outwardly flared portions 44c so that the force of the concussion wave emerging from the device 16 is minimized.

In accordance with another feature of the invention, material entering the device 16 from the flash tubes 18 and 20 is diverted or guided in an upward direction. Accordingly, the body 30 of the device 16 is provided with a pair of ramp portions 30a. The ramp portions 30a are somewhat concave or conical rather than flat, and as best appears from FIG. 2, a substantial portion of the mixture emerging from the flash tubes is deflected upwardly toward the spark gap 38.

When one burner is operating, a flame at its lighter port discharges products of combustion into the corresponding flash tube. These combustion products, which of course are not combustible, travel through the flash tube to the region of the device 16. If it is desired to ignite the other burner, its lighter port discharges a combustible air and gas mixture through the flash tube toward the device 16. It has been found that when the converging flows are both guided upwardly, as by ramp surfaces 30a, reliable ignition not heretofore possible is obtained.

Another feature of the present invention resides in the fact that much of the direct, straight line communication between the flash tubes 18 and 20 is prevented by the design of the body 30. The wall of the passageway 44 is defined by the ramp portions 3011 described above, and also by a generally oval, collar-shaped portion 30b defining the neck portion 44b of the passageway, and by outwardly flared upper portions 300 lying above the ramp portions 30a. As appears most clearly in FIG. 2, the ramp portions 30a and the neck portion 30b of the body provide an obstruction to free, straight line flow between the flash tubes 18 and 20. It is believed that this obstruction prevents or discourages combustible air-gas mixture from one flash tube from entering or reaching the other flash tube prior to or upon ignition, thereby decreasing or minimizing the eflect upon one burner of the concussion wave caused by ignition of the other burner.

The novel method of the present invention can conveniently be described in connection with the particular spark ignition device 16 described above, although it should be understood that the method may be practiced other than with the particular apparatus disclosed. In accordance with the method of the present invention, the flow of combustible gas air mixture from each of two burners is guided from the flash tubes 18 and 20 to the spark gap 38 in a novel way to prevent or minimize the ignition difliculties experienced heretofore. Upon emerging from the flash tube, the flow, or at least a substantial segment of the flow, is guided along a generally upwardly inclined path from the flash tube to the spark gap for ignition. Furthermore, in accordance with the invention, the flow may also be confined as it moves from the flash tube to the spark gap while its cross-sectional area is reduced.

While the present invention has been described with reference to a particular embodiment, many other modifications and embodiments may be devised by those skilled in the art. Details of the described embodiment should not be taken to limit the scope of the invention, which is defined in the following claims.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. An ignition apparatus adapted to be placed adjacent the outer ends of flash tubes for igniting spaced burners and comprising a body defining openings generally aligned with said flash tubes, a passageway with continuous walls extending between said openings for receiving flow from the flash tubes, said passageway having a central neck portion of relatively small cross sectional area, and said passageway further having outwardly flaring portions of increasing cross sectional area extending from the neck portion to said openings, and intermittently operable ignition means mounted within said neck portion.

2. The device of claim 1, said intermittently operable ignition means comprising a pair of spaced spark electrodes.

3. The ignition apparatus of claim 2, said flaring passageway portions providing upwardly extending ramps for the flow of gas toward said electrodes.

4. The ignition apparatus of claim 3, said ramps and said neck portion of said passageway providing substantial obstruction to direct, straight-line communication between said flash tubes.

5. A spark ignitor device for use in igniting a pair of spaced gas burners each having a flash ignition tube extending toward a central area and each having port means for discharging a flow of air gas mixture into the corresponding flash ignition tube prior to ignition, said ignitor device comprising a generally block-like body of electrically insulating and heat resistant material having a pair of outer surfaces each adapted to be disposed in proximity to the outlet end of one of the flash tubes, a passageway extending through said body and between said surfaces for the flow of air-gas mixture from the flash tubes into said body, said passageway including a relatively narrow central segment and generally flared end segments of increasing cross sectional area extending from said central segment to each of said outer surfaces, and a pair of electrically conductive electrodes supported by said body and extending from said body into said relatively narrow central segment of said passageway, said electrodes having spaced tips forming a spark gap within said central segment of said passageway.

6. The device of claim 5, said flared end segments of said passageway providing upwardly extending ramps for the flow of gas-air mixture toward said spark gap.

7. The device of claim 6, said ramps and said central segment providing substantial obstruction to direct, straight-line communication between the flash tubes.

References Cited UNITED STATES PATENTS 1,134,350 4/1915 Schaetzel 431-194 2,212,875 8/1940 Camp 43l-193 FOREIGN PATENTS 155,017 2/ 1954 Australia.

EDWARD G. FAVORS, Primary Examiner

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