Fuel integrated spark igniter

Abstract

A system and method for reducing the size of pilots utilizes an igniter arranged to combine the functionalities of a pilot with an ignition source by receiving and igniting a combustible via a spark formed in a gap internal to the igniter.

Description

Docket No. KES-24045-WO-PCTFUEL INTEGRATED SPARK IGNITERFIELD OF THE INVENTION

[0001] This invention pertains to ignition and sensing systems and more particularly to flame ignition and flame detecting or sensing systems. More specifically, the present disclosure includes the ignition systems having a spark type ignition.BACKGROUND

[0002] Pilot burners are known to create a stable pilot flame by combustion of a low flow rate (relative to the main burner) gaseous fuel-air mixture. The pilot flame is used to light a larger main burner, or a difficult to light fuel. Gas pilot designs normally include an ignition system and a flame detection system. The two most common types of ignition systems used in gas pilot burners are high tension (HT) and high-energy ignition (HEI). Flame detection is typically by a flame ionization detection (FID) system.

[0003] Ignitions systems typically include a main burner that supplies a fuel and air mixture to the furnace and a pilot burner adjacent to the main burner for igniting the fuel and air mixture. It would be beneficial to have a powerful ignition system, such as an HEI system, and a flame detection system that combines the pilot burner with the high energy ignition source, reducing the size of the pilot and also reducing a burden on the burner plenum.SUMMARY

[0004] The present disclosure includes one or more of the features recited in the appended claims and / or the following features which, alone or in any combination, may comprise patentable subject matter.

[0005] According to a first aspect of the present disclosure, a fuel integrated spark igniter includes a conduit, an insulator, a shell, and a gap igniter. The conduit includes a body having a longitudinal length defining a longitudinal axis of the conduit. The conduit is formed to include a passageway within the body and an inlet formed proximate a first end of the conduit. The inlet is configured to receive a combustible under pressure such that the combustible is urged along the passageway. The insulator is positioned on an exterior surface of the body of the conduit. The shell is positioned on the insulator. The shell is spaced apart from the conduit by a first distance to form a gap. The gap igniter is positioned on the insulator in the gap such that when a potential is induced between the conduit and the shell, an ignition spark is formed between the shell and the conduit.

[0006] According to some embodiments of the first aspect, the conduit is configured to operate as an electrode.Docket No. KES-24045-WO-PCT

[0007] According to some embodiments of the first aspect, the gap igniter includes a semiconductor material. The semiconductor material disposed within the gap between the shell and the conduit.

[0008] According to some embodiments of the first aspect, the inlet of the conduit includes a plurality of openings around a periphery of the body.

[0009] According to some embodiments of the first aspect, the shell comprises an opening adjacent to a second end of the conduit through which the combustible travels. During operation of the spark igniter, a spark may be formed prior to the opening adjacent to the second end of the conduit. The opening may include a nozzle. The nozzle may be configured to induce a flame root of a resulting flame to be positioned external to the shell. For example, the nozzle may be shaped to induce a flame root down stream of the nozzle, external to the shell.

[0010] According to some embodiments of the first aspect, the passageway is uniformly cylindrical.

[0011] According to some embodiments of the first aspect, the fuel integrated spark igniter includes a flame rod electrode. The flame rod electrode may be operable to detect a presence of a flame.

[0012] According to some embodiments of the first aspect, the passageway is formed to include a reducer. The reducer may be shaped such that a diameter of the passageway is reduced from a first diameter to a second diameter.

[0013] According to some embodiments of the first aspect, the passageway is formed to induce a pressure drop near a second end of the conduit. The shell may include an opening adjacent the second end of the conduit through which the combustible travels. The opening may be configured as a nozzle.

[0014] According to some embodiments of the first aspect, the passageway is formed to include a diffuser. The diffuser may be shaped to induce a pressure drop near a second end of the conduit. The diffuser may feed a plurality of openings at the second end of the conduit. The shell may include an opening adjacent the plurality of openings at the second end of the conduit through which the combustible travels. The opening may be configured as a nozzle.

[0015] According to some embodiments of the first aspect, the shell includes an opening adjacent a second end of the conduit through which the combustible travels. The opening may be configured as a nozzle.

[0016] According to some embodiments of the first aspect, the passageway is formed to include a diffuser to induce a pressure drop near a second end of the conduit. The shell may include a nozzle adjacent the second end of the conduit configured to feed a plurality ofDocket No. KES-24045-WO-PCT openings through which the combustible flows. During operation, a spark may be induced between the diffuser of the conduit and the nozzle of the shell.

[0017] According to some embodiments of the first aspect, the conduit includes an opening at the first end of the conduit for receiving a flow of pressurized air and a plurality of openings formed about a periphery of the body of the conduit. The plurality of openings may be configured to cause a fuel to be entrained into the flow of pressurized air to mix the fuel and air to be mixed to form the combustible.

[0018] According to some embodiments of the first aspect, the passageway is formed to include a diffuser to induce a pressure drop near a second end of the conduit. The shell may comprise an opening adjacent the second end of the conduit, the opening including a nozzle proximate the second end of the conduit. The shell may be formed to include an elongate cylindrical passageway through which the combustible is conducted.

[0019] According to some embodiments of the first aspect, the elongate cylindrical passageway of the shell further comprises a diffuser at an end opposite the nozzle. The shell may be configured such that a flame base is formed external to the shell when the combustible is ignited.

[0020] According to some embodiments of the first aspect, the fuel integrated spark igniter includes a mixer coupled to the conduit. The mixer may be configured to mix air and fuel to form the combustible that is introduced into the conduit. The mixer may include an outer chamber into which the fuel is introduced and a disruptor that causes air and the fuel to mix at the first end of the conduit.

[0021] According to some embodiments of the first aspect, the fuel integrated spark igniter includes a flame stabilizer secured to the shell. The flame stabilizer may be configured such that a root of a flame formed is positioned external to the shell and internal to the flame stabilizer. The flame stabilizer may be formed to include a cylindrical body with an internal cylindrical passageway. The root of the flame may be positioned in the internal cylindrical passageway.

[0022] According to a second aspect of the present disclosure, a fuel integrated spark igniter includes an elongated electrode, an insulator, a shell, and a gap igniter. The elongate electrode includes a cylindrical body that defines a longitudinal axis, an outer surface, and a head. The insulator is positioned on the outer surface of the elongate electrode. The insulator is formed to include a plurality of elongate passageways having longitudinal axes parallel to the longitudinal axis of the cylindrical body. The plurality of elongate passageways is configured to conduct a combustible along a length of the insulator. The shell is positioned on the insulator to form a gap between a portion of the shell and the head of the cylindrical body of the elongateDocket No. KES-24045-WO-PCT electrode. The gap igniter is positioned on the insulator in the gap such that when a potential is induced between the elongate electrode and the shell, an ignition spark is formed between the gap igniter and the elongate electrode.

[0023] According to some embodiments of the second aspect, the insulator is formed to cooperate with the head of the elongate electrode to form a diffuser.

[0024] According to some embodiments of the second aspect, the gap igniter includes a semiconductor material.

[0025] According to some embodiments of the second aspect, the shell includes an opening through which the combustible travels. During operation, a spark may be formed prior to the opening. The opening may include a nozzle. The nozzle may be configured to induce a flame root of a resulting flame to be positioned external to the shell.

[0026] According to some embodiments of the second aspect, at least one of the plurality of elongate passageways is uniformly cylindrical.

[0027] According to some embodiments of the second aspect, the fuel integrated spark igniter includes a flame rod electrode operable to detect a presence of a flame.

[0028] According to some embodiments of the second aspect, at least one of the plurality of elongate passageways is formed to induce a pressure drop near the gap. The shell may include an opening adjacent the gap through which the combustible travels. The opening may be configured as a nozzle.

[0029] According to a third aspect of the present disclosure, a method of operating a fuel integrated spark igniter includes controlling a flow of a combustible through a passageway within a body of a conduit and igniting the combustible with a gap igniter to form a flame downstream of the shell. The flow is controlled via a fuel delivery and control system. The body of the conduit has a longitudinal length defining a longitudinal axis of the conduit. An insulator is positioned on an exterior surface of the body of the conduit. A shell is positioned on the insulator, the shell spaced apart from the conduit by a first distance to form a gap. The gap igniter is positioned on the insulator in the gap. The combustible is ignited by inducing a potential between the conduit and the shell, forming an ignition spark between the shell and the conduit.

[0030] According to some embodiments of the third aspect, the method includes controlling the flow of the combustible, via the fuel delivery and control system, through an inlet formed proximate a first end of the conduit. The inlet may be configured to receive the combustible under pressure such that the combustible is urged along the passageway.

[0031] According to some embodiments of the third aspect, the method includes controlling a flow of pressurized air, controlling a flow of fuel, and mixing the pressurized airDocket No. KES-24045-WO-PCT and fuel to form the combustible. The flow of pressurized air may be controlled via the fuel delivery and control system, and flow from an air supply to the conduit through a first opening of the conduit. The flow of fuel may be controlled via the fuel delivery and control system, and flow from a fuel supply to a second opening of the conduit.

[0032] According to some embodiments of the third aspect, the method includes creating, via a flame detection circuit of the fuel delivery and control system, a potential across a gap between a flame rod electrode and a housing of the igniter and detecting, via the flame detection circuit, whether a conductive pathway is formed between the flame rod electrode and the housing to determine a status of the flame. The housing is coupled to the igniter and extends downstream of the shell to at least partially surround the flame. The flame rod electrode is coupled to the igniter and extends downstream of the shell parallel to the housing.

[0033] Additional features, which alone or in combination with any other feature(s), such as those listed above and / or those listed in the claims, can comprise patentable subject matter and will become apparent to those skilled in the art upon consideration of the following detailed description of various embodiments exemplifying the best mode of carrying out the embodiments as presently perceived.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The detailed description particularly refers to the accompanying figures in which:

[0035] Fig. 1 A is a side view of an igniter according to the present disclosure, the igniter including a conduit and a shell with an insulator disposed therebetween, the igniter configured to form an ignition spark in a gap between the conduit and the shell;

[0036] Fig. IB is a front view of the igniter of Fig. 1 A;

[0037] Fig. 1C is a cross-sectional view of the igniter of Fig. 1A taken along line 1C-1C ofFig. 1A;

[0038] Fig. ID is a perspective view of the igniter ofFig. 1A;

[0039] Fig. 2A is a side view of an alternative embodiment of an igniter having an internal passageway of the that reduces along a length of the passageway;

[0040] Fig. 2B is a front view of the igniter ofFig. 2A;

[0041] Fig. 2C is a cross-sectional view of the igniter of Fig. 2A taken along line 2C-2C ofFig. 2 A;

[0042] Fig. 2D is a perspective view of the igniter ofFig. 2A;

[0043] Fig. 3A is a side view of an alternative embodiment of an igniter, an end of the passageway shaped to form a diffuser, and the shell including an opening shaped to form a nozzle;

[0044] Fig. 3B is a front view of the igniter ofFig. 3 A;Docket No. KES-24045-WO-PCT

[0045] Fig. 3C is a cross-sectional view of the igniter of Fig. 3 A taken along line 3C-3C of Fig. 3A;

[0046] Fig. 3D is a perspective view of the igniter of Fig. 3 A;

[0047] Fig. 4A is a side view of an alternative embodiment of an igniter, an end of the conduit shaped to form a plurality of openings;

[0048] Fig. 4B is a front view of the igniter of Fig. 4A;

[0049] Fig. 4C is a cross-sectional view of the igniter of Fig. 4A taken along line 4C-4C of Fig. 4 A;

[0050] Fig. 4D is a perspective view of the igniter of Fig. 4A;

[0051] Fig. 5A is a side view of an alternative embodiment of an igniter, the shell shaped to form a plurality of openings;

[0052] Fig. 5B is a front view of the igniter of Fig. 5 A;

[0053] Fig. 5C is a cross-sectional view of the igniter of Fig. 5 A taken along line 5C-5C of Fig. 5 A;

[0054] Fig. 5D is a perspective view of the igniter of Fig. 5 A;

[0055] Fig. 6A is side a view of an alternative embodiment of an igniter, the shell including an elongate passageway;

[0056] Fig. 6B is a front view of the igniter of Fig. 6A;

[0057] Fig. 6C is a cross-sectional view of the igniter of Fig. 6A taken along line 6C-6C of Fig. 6 A;

[0058] Fig. 6D is a perspective view of the igniter of Fig. 6A;

[0059] Fig. 7A is a side view of an alternative embodiment of an igniter, the conduit shaped to form a plurality of openings at an end of the conduit opposite the shell;

[0060] Fig. 7B is a front view of the igniter of Fig. 7A;

[0061] Fig. 7C is a cross-sectional view of the igniter of Fig. 7A taken along line 7C-7C of Fig. 7 A;

[0062] Fig. 7D is a perspective view of the igniter of Fig. 7A;

[0063] Fig. 8A is a side view of an alternative embodiment of an igniter, the igniter comprising an elongate electrode, a shell, and an insulator disposed therebewteen, the insulator shaped to form passageways extending parallel to the electrode;

[0064] Fig. 8B is a front view of the igniter of Fig. 8 A;

[0065] Fig. 8C is a cross-sectional view of the igniter of Fig. 8 A taken along line 8C-8C of Fig. 8 A;

[0066] Fig. 8D is a cross-sectional view of the igniter of Fig. 8 A taken along line 8D-8D of Fig. 8 A;Docket No. KES-24045-WO-PCT

[0067] Fig. 8E is a perspective view of the igniter of Fig. 8 A;

[0068] Fig. 9A is a side view of an alternative embodiment of an igniter, the igniter including a mixer coupled to the conduit, the mixer shaped to form a disruptor;

[0069] Fig. 9B is a detail view of a portion of the igniter of Fig. 9A;

[0070] Fig. 9C is a cross-sectional view of the igniter of Fig. 9A taken along line 9C-9C of Fig. 9 A;

[0071] Fig. 10A is a side view of an alternative embodiment of an igniter, the igniter including a flame stabilizer coupled to shell;

[0072] Fig. 10B is a front view of the igniter of Fig. 10A;

[0073] Fig. 10C is a cross-sectional view of the igniter of Fig. 10A taken along line 10C-10C of Fig. 10 A;

[0074] Fig. 10D is a perspective view of the igniter of Fig. 10A;

[0075] Fig. 11 is a view of the igniter of Figs. 1 A-10D, the igniter including a flame rod electrode; and

[0076] Fig. 12 is a view of the igniter of Figs. 1 A-l 1 as part of an igniter system.DETAILED DESCRIPTION

[0077] An igniter 110 of the present disclosure, shown in Fig. 1, is arranged to receive a combustible, such as a gaseous fuel or a fuel / air mixture, and ignite the combustible by a spark formed in a gap internal to the igniter. The igniter 110 is arranged to combine the functionalities of a pilot with an ignition source, enabling the reduction of the size of pilots and / or torches, and which could replace larger pilot assemblies. Reducing the size of the pilot can reduce the burden (load, available space) on the burner plenum. In the illustrative embodiment, the igniter 110 is a high energy igniter configured to receive a high energy ignition source.

[0078] In the illustrative embodiment, a semiconductor material within the igniter 110 is used to cause the spark. The igniter 110 is arranged to reduce heat induced degradation of the semiconductor surface of the igniter. The igniter 110 is designed to have the ignition point to be internal to the igniter 110 instead of external, which allows for the placement of the internal spark gap to be either further towards the tip, or back further into the igniter, in order to customize things like expected life of service.

[0079] The igniter 110 of Fig. 1 is structured to be used in typical applications and configured to be received in existing ignition assemblies in a multitude of applications. The description below and the figures illustrate an igniter of the type used in a furnace having a main burner that supplies a fuel and air mixture to the furnace and a pilot burner adjacent to the main burner for igniting the fuel and air mixture. While the invention is described in the context of aDocket No. KES-24045-WO-PCT burner for such a furnace, it will be appreciated that the inventive ignition device is more broadly applicable as an ignition and flame detection system for fuels.

[0080] The fuel integrated spark igniter 110 includes a conduit 112, an insulator 118, and a shell 120. In the illustrative embodiments, the conduit 112 comprise an electrode and includes a central passageway 114 extending through a body of the conduit 112 from a first end 115 to a second end 119 of the conduit 112. In the illustrative embodiment, the conduit 112 is cylindrical in shape has a longitudinal length defining a longitudinal axis 111 of the conduit 112, the passageway 114 extending along the longitudinal axis 111. In the illustrative embodiments, the passageway 114 is uniformly cylindrical.

[0081] An inlet 116 is formed proximate to the first end 115 of the conduit 112. In some embodiments, as shown in Figs. 2-6, 8, and 10, the inlet forms an opening 213 intersecting the longitudinal axis 111 and is configured to receive a combustible 121 thought the opening 213. In some embodiments, the combustible 121 comprises air 734, fuel 735, or a mixture there of. In the illustrative embodiment, a center point of the opening 213 is disposed along the longitudinal axis 111. The combustible 121 is under pressure such that the combustible 121 is urged along the central passageway 114 of the conduit 112. In some embodiments, as shown in Fig. 1, the inlet 116 of the conduit 112 is shaped to form a plurality of openings 126 around the periphery of the body of the conduit 112 and extending through the exterior surface 117 of the conduit 112, through which the combustible 121 is received into the inlet 116. In some embodiments, as shown in Figs. 7 and 9 the inlet includes both periphery openings 126 and the opening 213 along the axis 111. In some embodiments, the openings 126 are be disposed anywhere along the length of the conduit 112. In some embodiments, additional or alternative structure may be used to draw air 734 into the fuel 735, such as a venturi device.

[0082] In the illustrative embodiment, the insulator 118 is cylindrical in shape and is positioned on an exterior surface 117 of the conduit 112. In the illustrative embodiment, the insulator 118 extends around an outer diameter of the conduit 112 and at least partially surrounds the conduit 112. The insulator 118 extends from the second end 119 of the conduit 112 at least partway down the exterior surface 117 of the conduit 112 along the longitudinal axis 111. In the illustrative embodiment, the insulator 118 comprises multiple segments, a first segment is disposed closer to the first end 115 of the conduit 112 and a second segment is disposed closer to the second end 119 of the conduit 112. In the illustrative embodiment, the first and second segments of the insulator 118 form a lap joint between the segments. In other embodiments, the insulator 118 may be a single, unitary structure. In other embodiments, the insulator 118 may be formed from more than two segments. In some embodiments, as shown in Fig. 2, the segments of the insulator 218 may be spaced apart along the axis 111 of the conduit 212 such that gaps areDocket No. KES-24045-WO-PCT formed between the segments of the insulator 218. The insulator 118 may extend past the second end 119 of the conduit 112, and may extend radially inwards at least partially over the second end 119 of the conduit.

[0083] In the illustrative embodiment, the shell 120 is a cylindrical cup shaped component comprising a cylindrical sidewall 123 and an end wall 125. The shell 120 is positioned on an exterior surface of the insulator 118 with the insulator 118 radially spacing apart the cylindrical sidewall 123 of the shell and the body of the conduit 112. In the illustrative embodiment, the insulator also axially spaces apart the second end 119 of the conduit 112 and the end wall 125 of the shell 120. The shell 120 is spaced apart from the second end 119 the conduit 112 by a first distance DI to form a gap 122. The gap 122 may also be referred to as a spark gap.

[0084] The shell 120 is shaped to form an opening 128 in the end wall 125 of the shell 120. In the illustrative embodiment, the opening 128 is disposed along the longitudinal axis 111 of the conduit 112, collinear with the internal passageway 114. The opening 128 is adjacent to the second end 119 of the conduit 112 through which the combustible 121 travels. The opening in the shell that the combustible 121 exits through may also be referred to as a gas jet. As described herein, the gas jet may comprise any suitable size or shaped opening needed to form the desired flame 160. As shown in embodiments described below, the gas jet may comprise multiple openings in the shell and / or openings at the second end of the conduit.

[0085] In the illustrative embodiments, a gap igniter 124 is positioned on the insulator 118 in the gap 122 such that when a potential is induced between the conduit 112 and the shell 120, an ignition spark is formed between the shell 120 and the conduit 112. The igniter 110 is configured such that the spark is formed prior / upstream to the opening 128 or between the opening 128 and the second end 119 of the conduit 112. In the illustrative embodiment, the gap igniter 124 includes a semiconductor material to cause a spark when a potential is introduced between the conduit 112 and the shell 120. In other embodiments, the gap igniter 124 may be another material or device capable of forming a spark. In the illustrative embodiment, the insulator 118, gap 122, and semiconductor material 124 are configured such that the spark is directed radially inwards.

[0086] During operation of the igniter 110, when an electronic potential is transmitted across the gap 122 as the combustible 121 is flowing through the passageway 114, the combustible 121 is ignited. By integrating the semiconductor material 124 on the internal body of the igniter 110, exposure of the semiconductor material to excessive direct or radiant heat within a combustion chamber of a burner is reduced. Additionally, by having the combustible 121 move at a velocity through the passageway 114 of igniter 110, the formed spark does notDocket No. KES-24045-WO-PCT directly impinge on a surface of the semiconductor material 124, further reducing physical wear or damage to the semiconductor material 124 and increasing life of service. In the illustrative embodiments, the gap 122 may have a relatively larger diameter and / or circumference than traditional igniters, providing a relatively larger surface area for the semiconductor material 124 to be distributed on. The increase surface area of the gap 122 provides room for a relatively larger amount of semiconductor material 124 within the igniter, which in turn increases the overall life of the igniter.

[0087] Fig. 2 shows an igniter 210 similar to the igniter 110 of Fig. 1 and with similar components. The conduit 212, insulator 218, and wall 223 of the shell 220 of the igniter 210 are elongated compared to the igniter 110 of Fig. 1, with the halves of the insulator 218 positioned on an exterior surface 217 of the conduit 212 and spaced apart with a gap between them, such that then first end 215 and the second end 219 are spaced further apart. As shown in Fig. 2, in some embodiments, the passageway 214 of the conduit 212 is formed to include a reducer 232 at some point along the length of the passageway 214. The reducer 232 may comprise a section of the conduit 212 where a diameter of the passageway 214 is reduced from a first diameter D2 closer to the first end 215 of the conduit 212 to a second diameter D2 closer to the second end of the conduit 212, where the first diameter D2 is larger than the second diameter D3. As indicated above, the inlet 216 at the first end 215 of the conduit 212 comprises an opening 213 intersecting and aligned with the longitudinal axis 111 of the conduit 212.

[0088] In the illustrative embodiment, the reducer 232 operates to increase the velocity of the combustible 121 flowing through the conduit 212 as the combustible 121 flows through the reducer 232. The increased velocity of the combustible 121 caused by the reducer 232 can decrease the likelihood of the flame 160 rooting inside the conduit 212, gap 122, and / or shell 220 of igniter 210. The increased velocity increases a stability of the flame 160 by affecting the location of where the flame 160 roots, in the illustrative case, downstream of the opening 128 of the shell 220.

[0089] Fig. 3 shows an igniter 310 similar to the igniters 110, 210 of Figs. 1-2 and with similar components. The conduit 312, insulator 318, and wall 323 of the shell 320 of the igniter 310 are elongated compared to the igniters 110, 210 of Figs. 1-2, such that then first end 315 and the second end 319 are spaced further apart. The insulator 318 comprises a single, unitary piece positioned on an exterior surface 317 of the conduit 312. An inlet 316 at a first end 315 of the conduit 312 comprises an opening 213 intersecting and aligned with the longitudinal axis 111 of the conduit 312. In some embodiments, as shown in Figs. 3-10, at least a portion of the opening 328 in the end wall 325 of the shell 320 is shaped to form a nozzle 342 adjacent the second endDocket No. KES-24045-WO-PCT319 of the conduit 312 and is configured to induce a flame root 162 of a resulting flame 160 to be positioned external to the end wall 325 of the shell 120.

[0090] In some embodiments, as shown in Figs. 3-7 and 9-10, the passageway is formed to induce a pressure drop near the second end of the conduit. In the illustrative embodiments, the pressure drop is induced by a shape of the passageway 314 forming a diffuser 336 at the second end 319 of the conduit. The diffuser 336 may be shaped to gradually increase a diameter of the passageway 314 to form a flared opening at the second end 319 of the conduit or a countersink shape. By introducing an area of lower pressure (compared to the combustion chamber) where the spark and ignition of the combustible 121 occurs, and igniting under this lower pressure, physical wear and damage to the semiconductor material 124 are reduced and life of service is increased compared to devices that ignite within the combustion chamber where high pressure exists, inducing a greater degree of wear.

[0091] In the illustrative embodiment, the diffuser 336 and / or any structure of the igniter designed to cause a pressure drop prior to the gap 122 and / or area of ignition of the combustible 121 may help ensure that the combustible 121 is well mixed prior to ignition. For example, when the combustible 121 is a mix of fuel and air, decreasing the pressure of the combustible 121 prior to the gap 122 allows for the fuel and air to more uniformly mix, creating a more uniform, consistent combustible 121 before the combustible 121 is ignited. Additionally or alternatively, decreasing the pressure locally of the combustible 121 extends the life of the igniter. For example, relatively higher pressure can push the spark formed against the spark gap 122, damaging the spark gap 122 and possible extinguishing the igniter. Dropping the pressure of the combustible 121 prior to the spark gap 122 helps prevent this and in turn can extend the lift and increase the reliability of the igniter.

[0092] Fig. 4 shows an igniter 410 similar to the igniters 310 of Fig. 3 and with similar components. The second end 419 of the conduit 412 of the igniter 410 is shaped to form a plurality of openings 438 between the passageway 314 and the shell 420 to help direct flow of the combustible 121 and control a shape of the flame 160. The openings 438 are disposed in line with the passageway 314, with axes of the openings 438 extending parallel to the axis 111 of the passageway 314. In the illustrative embodiment, the openings 438 are arranged in a circumferential pattern around the axis 111 of the passageway 314. The diffuser 436 of the passageway 414 feeds the combustible 121 to the plurality of openings 438. The openings 438 feed the combustible 121 to the opening 328 and nozzle 342 of the shell 320.

[0093] Fig. 5 shows an igniter 510 similar to the igniters 310 of Fig. 3 and with similar components. Additional or alternative internal geometry may be used to direct the flow of the combustible 121 and the shape of the flame 160. In some embodiments, as shown in Fig. 5, theDocket No. KES-24045-WO-PCT opening 528 in the end wall 525 of the shell 520 is shaped to form a plurality of openings 544 opposite the nozzle 542 in the end wall 525 to help direct flow of the combustible 121 and control a shape of the flame 160. In other embodiments, additional or alternative internal geometry may be used to direct the flow of the combustible 121 and the shape of the flame 60. The openings 544 are disposed in line with the passageway 314, with axes of the openings 544 extending parallel to or collinear with the axis 111 of the passageway 314. In the illustrative embodiment, the openings 544 are arranged in a circumferential pattern around the axis 111 of the passageway 314. The nozzle 542 of the shell 520 is formed on one side of the end wall 525 and feeds the plurality of openings 544 formed on the opposite side of the end wall 525 such that the combustible 121 flows from the nozzle 542 to the openings 544. The spark is induced between the diffuser 336 of the conduit 312 and the nozzle 542 of the shell 520.

[0094] Fig. 6 shows an igniter 610 similar to the igniter 310 of Fig. 3 and with similar components. In some embodiments, as shown in Fig. 6, the shell 620 includes an elongate cylindrical passageway 650 through which the combustible 121 is conducted. The passageway 650 extends through the end wall 625 of the shell 620 and distances the gap 122 where the ignition spark is formed from a distal end of the igniter 610 where the flame 160 forms. The increased distance between the gap 122 and the location of the flame 160 provided by the elongate cylindrical passageway 650 protects the gap 122 and the semiconductor from temperature and direct radiation from the combustion chamber and flame 160. The diffuser 336 of the passageway 314 feeds the combustible 121 to the gap 122. In the illustrative embodiment, the nozzle 642 of the proximate the second end 319 of conduit is disposed on an inner surface of the end wall 625 at one end of the elongate cylindrical passageway 650. The elongate cylindrical passageway 650 of the shell 620 is shaped to form a diffuser 646 at an external surface of the end wall 625, opposite the internal surface and the nozzle 642. A portion of the diffuser 646 forms the opening 628 in the end wall 625 of the shell 620.

[0095] Fig. 7 shows an igniter 710 similar to the igniters 310 of Fig. 3 and with similar components. In some embodiments, as shown in Fig. 7, the opening 213 forms an inlet 716 at a first end 715 of the conduit 712 that receives a flow of fuel 735, and a flow of pressurized air 734 flows through the plurality of openings 126. The plurality of openings 126 are shaped and disposed along the conduit 712 to cause the pressurized air 734 to be entrained into the flow of fuel 735 to mix the fuel 735 and air 734 together and form the combustible 121. Such a structure introduces the air 734 upstream of the ignition point and allows the air to be entrained into the gas flow path to allow the air-fuel mixture to travel through the center of the passageway 714 of the igniter for subsequent ignition.Docket No. KES-24045-WO-PCT

[0096] Fig. 8 shows an igniter 810 similar to the igniters of Figs. 1-7 and with similar components. In some embodiments, instead of the hollow conduit 112 of Fig. 1, the igniter 810 includes an elongate electrode 870 as shown in Fig. 8. The elongate electrode 870 extends from a first end 815 to a second end 819 and includes a cylindrical body defining a longitudinal axis 872, an outer surface 874 of the cylindrical body, and a head 878 at the second end 819 of the electrode 870. In the illustrative embodiment, the insulator 818 is positioned on the outer surface 874 of the electrode 870, extending at least partially around a circumference of the electrode 870, between the elongate electrode 870 and the shell 820. The shell 820 is positioned on an external surface of the insulator 818, surrounding the insulator 818 and the electrode 870. The end wall 325 of the shell 820 is spaced apart from the head 878 of the electrode 870 to form the gap 822 between a portion of the shell 820 and the head 878 of the electrode 870.

[0097] In the illustrative embodiment, the insulator 818 is shaped to form a plurality of elongate passageways 880 having longitudinal axes 882. The elongate passageways 880 extend parallel to the longitudinal axis 872 of the body of the elongate electrode 870. The elongate passageways 880 are configured to conduct the combustible 121 along the length of the insulator 818, from an inlet 816 closer to the first end 815 of the electrode 870 to the gap 822 at the second end 819. The semiconductor material 124 is positioned on the insulator 818 in the gap 822 such that when a potential is induced between the electrode 870 and the shell 820, an ignition spark is formed between the semiconductor material 124 and the electrode 870. In the illustrative embodiment, wherein the insulator 818 and the head 878 are shaped to form a diffuser 884.

[0098] Fig. 9 shows an igniter 910 similar to the igniter 310 of Fig. 3 and with similar components. In some embodiments, as shown in Fig. 9, the igniter 910 includes a mixer 952 coupled to the conduit 912. The mixer 952 is configured to mix air 734 and fuel 735 to form the combustible 121 that is introduced into the passageway 914 of the conduit 912. In the illustrative embodiment, the mixer 952 comprises a hollow cylindrical body that receives the first end 915 of the conduit 912, forming an outer chamber 954 into which fuel 735 is introduced. In the illustrative embodiment, the mixer 952 has an outer diameter substantially equal to an diameter of the outer wall 923 of the shell 920 such that an end of the mixer 952 is coupled to an end of the shell 920 opposite the end wall 325, forming a joint between the mixer 952 and the shell 920. In the illustrative embodiment, a portion of the insulator 318 extends into the mixer 952 between the conduit 912 and the mixer 952.

[0099] In the illustrative embodiment, as shown in Fig. 9, the first end 915 of the conduit 912, which is received by the mixer 952, is shaped to form a disruptor 956. The disruptor 956 includes a tapered portion at the first end 915 of the conduit 912, where the openings 926 of the inlet 916 are disposed in the slanted walls of the tapered portion. The disruptor 956 is disposedDocket No. KES-24045-WO-PCT within the outer chamber 954 of the mixer 952, which causes air 734 and fuel 735 to mix at a first end 915 of the conduit 912.

[0100] Fig. 10 shows an igniter 1010 similar to the igniters 310 of Fig. 3 and with similar components. In some embodiments, as shown in Fig. 10, the igniter 1010 includes a flame stabilizer 1058 secured to the shell 1020. An outer wall 1023 extends along the flame stabilizer 1058 and shell 1020, joining the two sections. In the illustrative embodiment, the flame stabilizer 1058 includes a cylindrical body 1064 with an internal cylindrical passageway 1066. The cylindrical body 1064 extends outwards from the end wall 1025 and the opening 328 of the shell 1020, and away from the conduit 312. The flame stabilizer 1058 is configured to form a root 162 of a flame 160 external to the shell 1020 and internal to the flame stabilizer 1058 or within the cylindrical passageway 1066 the flame stabilizer 1058.

[0101] Fig. 11 shows an igniter 1110 similar to the igniters 110 of Fig. 1 and with similar components, but which may be any of the igniters in Figs. 1-12. In some embodiments, as shown in Fig. 11, the igniter 1110 includes a flame rod electrode 1130 and housing 1131 disposed at the end of the igniter 1110 and operable to detect the presence of a flame through flame ionization detection techniques. The flame rod electrode 1130 is positioned at the end of the shell 120 within the housing 1131 such that when a flame 160 is formed, the flame rod electrode 1130 extends into the flame 160. The flame rod electrode 1130 is operable such that when no flame exists, no current flows between the flame rod electrode 1130 and the housing 1131. When a flame 160 exists adjacent to external end of the housing 1131, current flows between the flame rod and the housing 1131. The flame rod electrode 1130 is a conducting material that extends towards a wall of housing 1131 but is not in contact with housing 1131. The igniter 1110 may be in communication with a flame detection circuit 1261 that, when activated, creates a potential across a gap between flame rod electrode 1130 and the housing 1131. When a flame is present and extends between flame rod electrode 1130 and the housing 1131, there is a conductive pathway formed between flame rod electrode 1130 and the housing 1131.

[0102] Fig. 12 shows igniter 110 of Fig. 1 as part of an ignition system 1290 of a burner, but may be any of the igniters of Figs. 1-11. The burner may be similar to the COOLstar® burner available from John Zink Hamworthy Combustion®, using a fuel delivery and control system 1292 that is known in the art. In the illustrative embodiment, the fuel delivery and control system 1292 includes flame detection circuit 1261. When activated, the flame detection circuit 1261 creates a potential across a gap between flame rod electrode 1130 of the igniter 110 and a housing 1131 coupled to and disposed at the end of the igniter 110 (as shown in Fig. 11). When a flame is present and extends between flame rod electrode 1130 and the housing 1131, there is a conductive pathway formed between flame rod electrode 1130 and the housing 1131.Docket No. KES-24045-WO-PCT

[0103] In some embodiments, the igniter 110 may be contiguous with the centerline of an ignition rod of the ignition system 1290. The first end 115 of the igniter 110 is engaged with the fuel delivery and control system 1292, a fuel supply 1294, and an air supply 1296 to supply the combustible 121 to the igniter. The igniter 110 is arranged for the combustible 121 to be introduced either during startup only, for continuous use, or as needed during operation. The combustible 121 may be introduced through the passageway 114 either independently or while powering the sparking mechanism.

[0104] Although this disclosure refers to specific embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the subject matter set forth in the accompanying claims. For example, while the disclosure has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The disclosure is not limited to the disclosed embodiments. From reading the present disclosure, other modifications will be apparent to a person skilled in the art. Such modifications may involve other features, which are already known in the art and may be used instead of or in addition to features already described herein. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.

Claims

Docket No. KES-24045-WO-PCTWHAT IS CLAIMED IS:

1. A fuel integrated spark igniter comprising a conduit having a body having a longitudinal length defining a longitudinal axis of the conduit, the conduit formed to include a passageway within the body, an inlet formed proximate a first end of the conduit, the inlet configured to receive a combustible under pressure such that the combustible is urged along the passageway, an insulator positioned on an exterior surface of the body of the conduit, a shell positioned on the insulator, the shell spaced apart from the conduit by a first distance to form a gap, and a gap igniter positioned on the insulator in the gap such that when a potential is induced between the conduit and the shell, an ignition spark is formed between the shell and the conduit.

2. The fuel integrated spark igniter of claim 1, wherein the conduit is configured to operate as an electrode.

3. The fuel integrated spark igniter of claim 1, wherein the gap igniter comprises a semiconductor material.

4. The fuel integrated spark igniter of claim 1 , wherein the inlet of the conduit comprises a plurality of openings around a periphery of the body.

5. The fuel integrated spark igniter of claim 1, wherein the shell comprises an opening adjacent a second end of the conduit through which the combustible travels, a spark being formed prior to the opening.

6. The fuel integrated spark igniter of claim 5, wherein the opening comprises a nozzle.

7. The fuel integrated spark igniter of claim 6, wherein the nozzle is configured to induce a flame root of a resulting flame to be positioned external to the shell.

8. The fuel integrated spark igniter of claim 1, wherein the passageway is uniformly cylindrical.Docket No. KES-24045-WO-PCT9. The fuel integrated spark igniter of claim 1, further comprising a flame rod electrode operable to detect a presence of a flame.

10. The fuel integrated spark igniter of claim 1, wherein the passageway is formed to include a reducer wherein a diameter of the passageway is reduced from a first diameter to a second diameter.

11. The fuel integrated spark igniter of claim 1, wherein the passageway is formed to induce a pressure drop near a second end of the conduit.

12. The fuel integrated spark igniter of claim 11, wherein the shell comprises an opening adjacent the second end of the conduit through which the combustible travels, the opening configured as a nozzle.

13. The fuel integrated spark igniter of claim 1, wherein in the passageway is formed to include a diffuser to induce a pressure drop near a second end of the conduit, the diffuser feeding a plurality of openings at the second end of the conduit.

14. The fuel integrated spark igniter of claim 13, wherein the shell comprises an opening adjacent the plurality of openings at the second end of the conduit through which the combustible travels, the opening configured as a nozzle.

15. The fuel integrated spark igniter of claim of claim 1, wherein the shell comprises an opening adj acent a second end of the conduit through which the combustible travels, the opening configured as a nozzle.

16. The fuel integrated spark igniter of claim 1, wherein in the passageway is formed to include a diffuser to induce a pressure drop near a second end of the conduit, the shell comprises a nozzle adjacent the second end of the conduit, the nozzle feeding a plurality of openings through which the combustible flows, a spark being induced between the diffuser of the conduit and the nozzle of the shell.

17. The fuel integrated spark igniter of claim 16, wherein the conduit comprises an opening at the first end of the conduit for receiving a flow of pressurized air and a plurality of openings formed about a periphery of the body of the conduit, the plurality ofDocket No. KES-24045-WO-PCT openings configured to cause a fuel to be entrained into the flow of pressurized air to mix the fuel and air to be mixed to form the combustible.

18. The fuel integrated spark igniter of claim 1, wherein in the passageway is formed to include a diffuser to induce a pressure drop near a second end of the conduit, the shell comprises an opening adjacent the second end of the conduit, the opening including a nozzle proximate the second end of the conduit, the shell formed to include a elongate cylindrical passageway through which the combustible is conducted.

19. The fuel integrated spark igniter of claim 18, wherein the elongate cylindrical passageway of the shell further comprises a diffuser at an end opposite the nozzle.

20. The fuel integrated spark igniter of claim 19, wherein the shell is configured such that a flame base is formed external to the shell when the combustible is ignited.

21. The fuel integrated spark igniter of claim 1, further comprising a mixer coupled to the conduit, the mixer configured to mix air and fuel to form the combustible that is introduced into the conduit.

22. The fuel integrated spark igniter of claim 21, wherein the mixer includes an outer chamber into which the fuel is introduced and a disruptor that causes air and the fuel to mix at the first end of the conduit.

23. The fuel integrated spark igniter of claim 1, further comprising a flame stabilizer secured to the shell.

24. The fuel integrated spark igniter of claim 23, wherein the flame stabilizer is configured such at a root of a flame formed is positioned external to the shell and internal to the flame stabilizer.

25. The fuel integrated spark igniter of claim 24, wherein the flame stabilizer is formed to include a cylindrical body with an internal cylindrical passageway the root of the flame being positioned in the internal cylindrical passageway.

26. A fuel integrated spark igniter comprising:Docket No. KES-24045-WO-PCT an elongate electrode having a cylindrical body defining a longitudinal axis and an outer surface, and a head; an insulator positioned on the outer surface of the elongate electrode, the insulator formed to include a plurality of elongate passageways having longitudinal axes parallel to the longitudinal axis of the cylindrical body, the plurality of elongate passageways configured to conduct a combustible along a length of the insulator; a shell positioned on the insulator to form a gap between a portion of the shell and the head of the cylindrical body of the elongate electrode; and a gap igniter positioned on the insulator in the gap such that when a potential is induced between the elongate electrode and the shell, an ignition spark is formed between the gap igniter and the elongate electrode.

27. The fuel integrated spark igniter of claim 26, wherein the insulator is formed to cooperate with the head of the elongate electrode to form a diffuser.

28. The fuel integrated spark igniter of claim 26, wherein the gap igniter comprises a semiconductor material.

29. The fuel integrated spark igniter of claim 26, wherein the shell comprises an opening through which the combustible travels, a spark being formed prior to the opening.

30. The fuel integrated spark igniter of claim 29, wherein the opening comprises a nozzle.

31. The fuel integrated spark igniter of claim 30, wherein the nozzle is configured to induce a flame root of a resulting flame to be positioned external to the shell.

32. The fuel integrated spark igniter of claim 26, wherein at least one of the plurality of elongate passageways are uniformly cylindrical.

33. The fuel integrated spark igniter of claim 26, further comprising a flame rod electrode operable to detect a presence of a flame.

34. The fuel integrated spark igniter of claim 26, wherein at least one of the plurality of elongate passageways is formed to induce a pressure drop near the gap.Docket No. KES-24045-WO-PCT35. The fuel integrated spark igniter of claim 34, wherein the shell comprises an opening adjacent the gap through which the combustible travels, the opening configured as a nozzle.

36. A method of operating a fuel integrated spark igniter comprising: controlling a flow of a combustible, via a fuel delivery and control system, through a passageway within a body of a conduit, the body having a longitudinal length defining a longitudinal axis of the conduit, an insulator positioned on an exterior surface of the body of the conduit, and a shell positioned on the insulator, the shell spaced apart from the conduit by a first distance to form a gap; and igniting the combustible with a gap igniter to form a flame downstream of the shell, the gap igniter positioned on the insulator in the gap by inducing a potential between the conduit and the shell, forming an ignition spark between the shell and the conduit.

37. The method of claim 36, wherein the method further comprises controlling the flow of the combustible, via the fuel delivery and control system, through an inlet formed proximate a first end of the conduit, the inlet configured to receive the combustible under pressure such that the combustible is urged along the passageway.

38. The method of claim 36, wherein the method further comprises: controlling, via the fuel delivery and control system, a flow of pressurized air from an air supply to the conduit through a first opening of the conduit; and controlling, via the fuel delivery and control system, a flow of fuel from a fuel supply to a second opening of the conduit; and mixing the pressurized air and fuel to form the combustible.

39. The method of claim 36, wherein the method further comprises: creating, via a flame detection circuit of the fuel delivery and control system, a potential across a gap between a flame rod electrode and a housing of the igniter, the housing coupled to the igniter and extending downstream of the shell to at least partially surround the flame, the flame rod electrode coupled to the igniter and extending downstream of the shell parallel to the housing; and detecting, via the flame detection circuit, whether a conductive pathway is formed between the flame rod electrode and the housing to determine a status of the flame.

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