Title of Invention	A METHOD AND SYSTEM FOR MONITORING OPERATION OF A FLAME IGNITOR
Abstract	The present invention relates to a method and system for monitoring operation of a flame ignitor. Techniques for mentoring operation of a flame ignitor (200) are provided. In one embodiment, multiple inputs are received. The inputs are received from at least one of a first group of inputs and a second group of inputs. The first group includes a flame rod voltage, a stop signal for deactivation of the flame ignitor, a fuel supply interruption signal, and an air supply interruption signal. The second group includes a start signal for activation of the flame ignitor (200), and a flame proven signal indicating presence of a flame produced by the flame ignitor (200). If inputs from the first group are received, a cause of a failure of the flame ignitor (200) is determined. If inputs from the second group are received, a reliability of the flame ignitor (200) is determined.

Title of Invention

A METHOD AND SYSTEM FOR MONITORING OPERATION OF A FLAME IGNITOR

Abstract

The present invention relates to a method and system for monitoring operation of a flame ignitor. Techniques for mentoring operation of a flame ignitor (200) are provided. In one embodiment, multiple inputs are received. The inputs are received from at least one of a first group of inputs and a second group of inputs. The first group includes a flame rod voltage, a stop signal for deactivation of the flame ignitor, a fuel supply interruption signal, and an air supply interruption signal. The second group includes a start signal for activation of the flame ignitor (200), and a flame proven signal indicating presence of a flame produced by the flame ignitor (200). If inputs from the first group are received, a cause of a failure of the flame ignitor (200) is determined. If inputs from the second group are received, a reliability of the flame ignitor (200) is determined.

Full Text	FIELD OF THE INVENTION The present invention relates to an ignitor for a fossil fuel fired combustion chamber, and more particularly to an ignitor having improved performance and reliability. BACKGROUND OF THE INVENTION In order to begin the combustion process inside a fossil fuel fired combustion chamber, such as that found in industrial and utility boilers, there must be an energy source to begin the self-sustaining combustion reaction of main fuel and air inside the combustion chamber Current practice is to use a light fuel oil, natural gas, or propane ignitor of a size between input of 0.5 to 20 Million Btu/hr for each of several fuel admission compartments of the combustion chamber. Igniters have a dedicated fuel and air supply and an energy source, typically a spark plug, to produce a flame. In operation, fuel and air are introduced to the ignitor and a spark provides the energy to begin a self- sustaining reaction that keeps the ignitor burning. Proof that the ignitor is operating is established through the use of a flame detector, such as a flame rod, a thermal sensing device, or an optical sensor, that is often integral with the ignitor. Once the ignitor is proven to be operating, main fuel and air for the combustion chamber can be introduced, often after utilizing the ignitor to preheat the combustion chamber. The energy from the ignitor (the ignitor flame), allows the combustion reaction of the main fuel and air to begin. Generally, once the main fuel and air is ignited the combustion reaction is self-sustaining, and the ignitor can be turned off. However, in some cases, such as due to low volatility of the main fuel, it is necessary to leave the ignitor on in order to keep the main combustion reaction continuing. In other cases, ignitors are left to burn continuously, as may be required by safety laws. For reasons of safety it is important that the ignitor reliably begin burning on command, and that it be able to be confirmed that the ignitor is producing a flame to insure the safe combustion of the main fuel and air. Failure of an ignitor can result in unsafe accumulations of unburned main fuel and air, resulting in massive explosive damage. In one known type of coal-fired boiler unit, one or more relatively high-capacity oil burners (warm-up guns) are started by one or more oil- or gas-fired ignitors to preheat the combustion chamber Once the combustion chamber has been brought up to the proper starting temperature, coal nozzles are ignited by the oil- or gas-fired igniters, or by the warm-up guns themselves. At higher boiler loads, i.e., when the amount of coal supplied by the coal nozzles is great, the combustion chamber can typically maintain stable combustion of the pulverized coal. However, when the load goes down and the coal supply is thereby decreased, the stability of the pulverized coal flame is also decreased, and it is therefore common practice to use the igniters or warm-up guns to maintain flame in the combustion chamber, thus avoiding the accumulation of unburned coal dust in the combustion chamber and the associated danger of explosion. Certain portions of an ignitor mounted in a windbox compartment of a combustion chamber are subjected to relatively high temperatures, typically on the order of 500 degrees Fahrenheit or higher, in some conventional igniters, there is a risk that an ignitor wire supplying energy to an ignitor spark element may burn up due to the high temperatures, especially when insufficient cooling air is supplied to the ignitor. Recently, a gas-fired ignitor overcoming this problem has been proposed. However, oil-fired igniters are still subject to this problem. Accordingly, a need exists for an oil-fired ignitor which provides a reliable spark action and which has improved survivability in a high temperature environment. An igniter's spray of fuel and air (the combustive mix) is produced by an atomizer. The spray produced by conventional atomizers used in oil- fired igniters frequently has too many large droplets, resulting in insufficient oxygen at the base of the flame. An insufficient amount of oxygen results in excessive smoke formation, resulting in an unacceptable opacity from the stack. Accordingly, a need exists for an oil-fired igniter that produces a spray with more available oxygen at the flame base. Introduced above, conventional igniters, no matter the type of igniter fuel utilized, include some sort of flame sensing device which may be mechanical or optical. The output of such a flame sensing device is transmitted to a control room where operational decisions are made based upon the sensed flame. If no igniter flame is detected when one is expected to be present, repair personnel must service the non-performing igniter based upon only the information that a flame is not present. Lack of a flame could be due to any one of a faulty igniter fuel supply, a faulty igniter compressed air, or a faulty igniter spark source. Further, a flame could actually be present, and the flame detector itself could be sending a false lack of flame signal. Currently, there is no way for service personnel to know what ignitor component has failed without physically examining that igniter. Thus, many man-hours are spent attempting to determine the reason an igniter has failed. If repair personnel had an indication of a reason for failure prior to beginning a repair operation, many of those man-hours could be saved. Accordingly, a need exists for an igniter which provides information indicating which component has failed. Aside from an ignitor failure, routine scheduled maintenance of igniters is typically performed in an effort to prevent failure. A single utility boiler typically can include upwards of 64 individual igniters that must be maintained. Performing this routine maintenance is both costly and time consuming. That is, each ignitor, whether functioning properly or not, is regularly inspected. If those igniters that required service could be identified, not only could the time and cost expenses of services all igniters be saved, but costs associated with ignitor failure, such as boiler down time, could be saved. Accordingly, a need exists for an ignitor in which the necessity of service can be determined prior to failure. OBJECTS OF THE INVENTION It is an object of the present invention to provide an oil-fired ignitor having reliable spark action in a high temperature environment. It is another object of the present invention to provide an oil-fired ignitor having an improved atomizer. Another object of the present invention is to provide an ignitor having higher reliability than conventional igniters. Still another object of the present invention is to provide an igniter in which an indication of which component, or components, are responsible for an igniter failure is available. Yet another object of the present invention is to provide an igniter in which the necessity of service can be determined prior to an igniter failure. The above-stated objects, as well as other objects, features, and advantages, of the present invention will become readily apparent from the following detailed description which is to be read in conjunction with the appended drawings. SUMMARY OF THE INVENTION Methods and systems for monitoring operation of a flame igniter are provided herein. The flame igniter is used to begin and/or support the combustion process inside a fossil fuel fired combustion chamber. A system includes at least a memory and a processor. A processor can be any type of processor capable of functioning to implement the techniques described herein. A memory can be any type of memory capable of storing information and communicating with a processor. In a first embodiment of the present invention, multiple inputs from at least one of a first group of inputs and a second group of inputs are received. That is, the multiple inputs could all come from the first group, could all come from the second group, or come from a mixture of the first and second groups. The first group of inputs includes a flame rod voltage, a stop signal for deactivation of the flame igniter, a fuel supply interruption signal, and an air supply interruption signal. A flame rod voltage measures the intensity of flame, with the voltage being proportional to the intensity of the flame. A stop signal causes the flame ignitor to cease operation. A fuel supply interruption signal indicates that the fuel supply for the flame igniter has been interrupted, and an air supply interruption signal indicates that the air supply for the flame igniter has been interrupted. The second group of inputs includes a start signal for activation of the flame igniter and a flame proven signal indicating presence of a flame produced by the flame ignitor A start signal causes the flame ignitor to begin operation. A flame proven signal indicates that the ignitor is successfully operating, i.e., producing a flame If inputs from the first group are received, a determination of a cause of a failure of the flame ignitor is made. This determination is made based upon the received inputs from the first group If inputs from the second group are received, a determination of the reliability of the flame ignitor is made. This reliability determination is made based upon the received inputs from the second group. It should be understood that inputs from both groups may be received. In one aspect of this first embodiment, information associated with one or more determinations made based upon the received inputs is transmitted. This could include a single transmission, or multiple transmissions. Further, a transmission could be, as desired, made to a single entity, or multiple entities. Also, a transmission could be a scheduled transmission, could be made whenever a determination is made, or could be made ad hoc. In a further aspect, the information associated with a determination is transmitted to at least one of a control room associated with a combustion chamber with which the flame ignitor is associated, and a location remote from the control room. In an even further aspect, the remote location is associated with an entity responsible for servicing the flame ignitor. The responsible entity could be an entity other than the entity to which the combustion chamber belongs. In another aspect of this first embodiment, multiple start signals and multiple flame proven signals are received. Each received input is stored. The number of stored flame proven signals is divided by the number of stored start signals to determine the reliability of the flame ignitor. In a further aspect, a warning signal is transmitted when the determined reliability violates a reliability set-point. That is, if the determined reliability does not meet a predetermined criteria, a warning signal is transmitted. This transmission could be to the control room, could be to a remote location, could be to another location, or could be to multiple locations. According to still another aspect of this embodiment multiple inputs from group one are received. An indication of each received input from group one is stored. This indication identifies the particular type of group one input received. Also, a time that each group one input is received is stored. The cause of failure is determined based, at least in part, upon the stored time information. In a further aspect, the cause of failure is determined based upon the first received group one input. In yet another aspect of the first embodiment, information associated with one or more determinations is outputted via a display on the flame ignitor. That is, the flame ignitor has a display that is configured to show information associated with at least one determination that has been made based upon the multiple received inputs. This information could be related to one, or both of, a cause of failure of the flame ignitor and a reliability of the flame ignitor. According to a second embodiment for monitoring operation of a flame scanner, multiple inputs that are each associated with operation of the flame scanner are received. An operational parameter of the flame ignitor is then determined based upon one or more of the received inputs In one aspect of this second embodiment, the determined operational parameter is one of a cause of a failure of the flame ignitor, and a reliability of the flame ignitor. In another aspect of the flame ignitor, each input is one of a flame rod voltage, a stop signal for deactivation of the flame ignitor, a fuel supply interruption signal, an air supply interruption signal, a start signal for activation of the flame ignitor, and a flame proven signal, each discussed above. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS In order to facilitate a fuller understanding of the present invention, reference is now made to the appended drawings. These drawings should not be construed as limiting the present invention, but are intended to be exemplary only. Figure 1 a schematic plan view of a fossil fuel-fired furnace having a preferred embodiment of the ignitor of the present invention installed thereon. Figure 2 is a simplified depiction of an oil-fired ignitor in accordance with one aspect of the present invention. Figure 3 is a simplified depiction of processing electronics in accordance with certain aspects of the present invention for use with an ignitor. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring now to the drawings, and more particularly to Figure 1, there is depicted a conventional fossil fuel-fired power generation system, generally designated by the reference numeral 10, having installed therein a preferred embodiment of the igniter of the present invention. It should be understood that the ignitor of the present invention could be utilized in. industrial or utility installations other than that depicted in Figure 1 The fossil fuel-fired power generation system 10 includes a fossil fuel-fired steam generator 12 and an air preheater 14. The fossil fuel-fired steam generator 12 includes a burner region. It is within the burner region 16 of the fossil fuel-fired steam generator 12 that the combustion of fossil fuel and air, in a manner well-known to those skilled in this art, is initiated. To this end, the fossil fuel-fired steam generator 12 is provided with a conventional firing system 18. The firing system 18 includes a housing, preferably in the form of a windbox 20. The windbox 20 includes a plurality of compartments, each designated 22. In conventional fashion, some of the compartments 22 are designed to function as fuel compartments from which fossil fuel is injected into the burner region 16, while others of the compartments 22 are designed to function as air compartments from which air is injected into the burner region 16. The fossil fuel is supplied to the windbox 20 by a conventional fuel supply means, not shown in the interest of maintaining clarity of illustration in the drawing. At least some of the air which is injected into the burner region 16 for purposes of effecting combustion of the injected fuel is supplied to the windbox 20 from the air preheater 14 through the duct 24. It is within the burner region 16 of the fossil fuel-fired steam generator 12 that the combustion of the fossil fuel and air is initiated The hot gases that are produced from this combustion of the fossil fuel and air rise upwardly in the fossil fuel-fired steam generator 12. During the upwardly movement thereof in the fossil fuel-fired steam generator 12, the hot gases, in a manner well-known to those skilled in this art, give up heat to fluid flowing through tubes (not shown in the interest of maintaining clarity of illustration in the drawing) that in conventional fashion line all four of the walls of the fossil fuel-fired steam generator 12. Then, the hot gases flow through the horizontal pass 26 of the fossil fuel-fired steam generator 12, which in turn leads to the rear gas pass 28 of the fossil fuel-fired steam generator 12. Although not shown in Figure 1, it should be understood that the horizontal pass 26 would commonly have suitably provided therein some form of a heat transfer surface. Similarly, heat transfer surface, as illustrated at 30 and 32, is suitably provided within the gas pass 28. During passage through the rear gas pass 28 the hot gases give up heat to the fluid flowing through the tubes of the heat transfer surface. Upon exiting from the rear gas pass 28 of the fossil fuel-fired steam generator 12 the hot gases are conveyed to the air preheater 14. To this end, the fossil fuel-fired steam generator 12 is connected from the exit end 34 thereof to the air preheater 14 by means of duct work 36. After passage through the air preheater 14, the now relatively cooler hot gases are further conducted to conventional treatment apparatus which are not illustrated in the interest of clarity. The fossil fuel-fired steam generator 12 is provided with a preferred embodiment of the ignitor of the present invention. Figure 2 shows an oil- fired igniter 200 mounted in one of the windboxes of the fossil fuel-fired steam generator 12. It should be understood that the fossil fuel-fired steam generator 12, as well as any other industrial or utility installation, can be provided with any desired number of the ignitor of the present invention The ignitor 200 is mounted inside a pipe 201 secured to a windbox wall 205. The ignitor 200 includes a conventional flame rod 210, a spark extension assembly 215, a compressed air conduit 225, a fuel conduit 230 collinear and disposed within the compressed air conduit 225, a bluff body 240 disposed at the terminus of the compressed air conduit 225, and an atomizer 235 disposed within the bluff body 240. The spark extension assembly 215 includes a solid conductor with an outer ceramic insulation coating, enabling the spark extension assembly 215 to survive temperatures greater than 1000 degrees Fahrenheit. The solid conductor, preferably made of stainless steel, though it could be any other conductive metal, connects to an external electrical power source (not shown in the Figures) at terminus 255. At the opposite end of the spark extension assembly 215 is a high energy ignitor tip 220. The solid conductor receives electrical current from the power source and conducts the electrical current to the high energy ignitor tip 220, which produces a spark to ignite a spray mixture of the compressed air and fuel released by the atomizer 235. United States Patent Number 6,582,220, assigned to the assignee of the present invention and which is incorporated herein in its entirety, discloses an elongate electrode assembly suitable for use as the spark extension assembly 215. The external power source provides a high energy pulse of electricity to the spark extension assembly 215. Preferably, the pulse is 12 joules for a microsecond pulse period, though other high energy levels and/or pulse periods could be provided by the external power supply Because of the high energy pulse, any unburned fuel and combustion products that have accumulated on the high energy ignitor tip 220 are removed by the resultant spark. Thus, degradation of the performance of the spark extension assembly 215 due to build up is prevented. The spark from the high energy ignitor tip 220 is positioned in the output spray of the atomizer 235. The spark ignites the compressed air/fuel spray produced by the atomizer 235. The configuration of the atomizer 235 allows additional compressed air to come straight out of the center of the atomizer 235 into the central core of the spray to improve the fuel to air ratio. This feature results in an increased amount of oxygen at the flame base, which reduces opacity. The bluff body 240 is spherical, or essentially spherical, with a truncated face. The spherical shape minimizes air flow friction losses and permits substantially greater mass flow of air through the pipe 201, which in turn allows proper fuel mixing for a greater amount of fuel for combustion. United States Patent Number 6,443,728, assigned to the assignee of the present invention and which is incorporated herein in its entirety, discloses a structure suitable for use as the bluff body 240. In operation, the flame rod 210 is charged to approximately 40 volts DC, allowing for an optimum signal-to-noise ratio. As flame ions interact with the flame rod 210, the voltage dips and rises. These voltage fluctuations are measured by sensor 265. The measured voltage is transmitted to processing electronics, to be discussed below. With reference to Figure 3, the processing electronics 400, which can, as desired, be housed proximate to or remote from the ignitor 200, include a digital signal processor 405 and a memory 410. The digital signal processor 405 communicates with the memory 410. As desired, and as shown in Figure 3, the digital signal processor 405 and the memory 410 may be combined into a single unit. The digital signal processor 405 is preferably of a minimum specification of 16-bit design operating at 40 million instructions per second, however other designs could be utilized, as desired It should be understood that the control electronics shown in Figure 3 and described below can be utilized with igniters burning any type fuel, not just the oil-fired ignitor 200 shown in Figure 2. The digital signal processor 405 includes multiple inputs for receiving information and multiple outputs for communicating the received information and determined information to operators and service technicians. The inputs include the flame rod voltage sensed by sensor 265 discussed above, a start/stop signal input, a fuel flow switch input, and an air pressure switch input The start/stop signal input is associated with signals generated in the control room indicating a desire to activate or deactivate the ignitor 200. That is, whenever an operator attempts to start the ignitor 200, a start signal is received at the digital signal processor 405, and whenever an operator stops the ignitor 200, a stop signal is received at the digital signal processor 405. Indications of these start and stop signals are stored in the memory 410 by the digital signal processor 405, along with a time each was received. These stored indications will be further discussed below. The fuel flow switch input receives signals from a fuel line sensor (not shown in the Figures) on a fuel line to the ignitor 200. Whenever fuel flow is interrupted, or decreases below a certain level, the fuel line sensor sends a fuel flow warning signal to the digital signal processor 405. A fuel flow warning signal causes a trip of the -gnitor 200. In a trip, as well as in an operator-ordered shut down, the igniter's fuel, air, and spark are discontinued, causing the ignitor flame to extinguish. The digital signal processor 405 stores an indication of the fuel flow warning signal in the memory 410, along with the time such was received. The air pressure switch input receives signals from a compressed air line sensor (not shown in the Figures) on a compressed air line to the ignitor 200. Whenever compressed air flow is interrupted, or decreases below a certain level, the compressed air line sensor sends a air flow warning signal to the digital signal processor 405. An air flow warning signal also causes a trip of the ignitor 200. The digital signal processor 405 stores an indication of the air flow warning signal in the memory 410, along with the time such was received. The memory also stores trip set points associated with the sensed flame intensity on the flame rod 210. If the DC voltage measured by sensor 265 and input to the digital signal processor 405 violates a trip set point, the digital signal processor 405 trips the ignitor 200. The digital signal processor 405 also calculates an AC voltage based upon the input DC voltage from sensor 265. Likewise, if the calculated AC voltage violates a trip set point, the digital signal processor 405 trips the ignitor 200. Whenever the ignitor 200 is tripped due to violation of a set point, an indication of such, along with the time, is stored in the memory 410 by the digital signal processor 405. Separate from the trip set point processing described above, the sensed DC voltage and the calculated AC voltage is available as a real-time output, shown as Flame Intensity AC & DC output. A related output is the Ignitor Proven output. This output is a state-based output. That is, if the sensed DC voltage and the calculated AC voltage do not violate a set point, a high signal is output Whereas, if one or both of the AC and DC voltages violates a set point, a low signal is output. Outputs will be further discussed below. Also based upon the sensed flame rod DC voltage and calculated flame rod AC voltage is the Flame Rod Dirty/Shorted output. This output is also a state-based output. If the flame rod 210 is operating property, the Flame Rod Dirty/Shorted output will be high. However, if the sensed DC voltage falls to zero, or another stored value that indicates a shorted flame rod, the Flame Rod Dirty/Shorted output will be low. Also, the digital signal processor 405 monitors the calculated AC voltage. Stored in the memory 410 is an indication of an expected AC voltage waveform. If the calculated AC voltage does not match the expected AC voltage waveform, or deviates from the expected AC voltage waveform more than an acceptable amount the Flame Rod Dirty/Shorted output will be low. The stored information based upon the received inputs discussed above forms a first-out logic architecture. The first-out architecture aids in determining why an operating igniter has failed. Whenever an ignitor trips, no matter the cause, signals indicating improper fuel flow, improper air flow, and improper voltage, as discussed above, will each be received. This is because once an ignitor shuts down, fuel and air flow cease, causing the flame to extinguish, which in turn causes the flame rod to detect a lack of a flame. Because of stored time information associated with each of these variables, the cause of the trip can easily be determined. It should be understood that the stored time information could simply be ordering information, or could be an actual time. As an example of the first-out logic, if the ignitor 200 trips because of the an improper fuel flow, the stored indication of improper fuel How will have the earliest time indication because the improper air flow signal and the lack of voltage signal will be received subsequent to the improper fuel flow signal. The digital signal processor 405 is programmed to determine which of the stored signals associated with a particular failure was received first and output this determination to an operator or service technician via the First-Out Logic output. Introduced above, an indication of each received start signal is stored in memory 410. Also stored in memory 410 is an indication of each actual start. Each time the digital signal processor 405 determines that the flame rod detects a flame within a certain time period following receipt of a start signal the digital signal processor 405 stores an indication of a successful start in the memory 410. The number of received start signals and the number of successful starts is the basis for determining reliability of the ignitor. Thus, the digital signal processor 405 divides the number of successful starts indicated in the memory 410 by the number of received start signals indicated in the memory 410 to produce a percentage reliability indication. This information is available via the % Reliability output. The percentage reliability indication is especially useful in determining degradation of the spark extension assembly 215, as this component is most often associated with a failed start attempt. The digital signal processor 405 is programmed to not only calculate the percentage reliability, but also report a need for service based upon that information. As desired, the digital signal processor 405 can be programmed to transmit a service request when the calculated percentage reliability falls below a certain set point, stored in memory 410. Alternatively, or perhaps in combination, the digital signal processor 405 can be programmed to transmit a service request when the calculated percentage reliability begins to trend downward, perhaps even at a predetermined rate stored in the memory 410. A service request is transmitted via a Link to Remote, to be discussed further below. The digital signal processor 405 has a user interface through which all outputs discussed above are available. The user interface includes a backlit LED bargraph display for communicating each output. Thus, via the display, an operator or service technician can view the DC and the AC flame intensity and the percent reliability, as well as the Ignitor Proven and Flame Rod Dirty/Shorted outputs. Especially beneficial, the digital signal processor- determined cause of a trip is also available via the display. Also, the user interface includes a user input, preferably password protected, through which an operator or service technician can adjust the stored voltage trip set points and the shorted voltage Also shown in Figure 3 is the Link to Remote input/output Through the Link to Remote, all outputs discussed above can be transmitted to a remote location, such as a local control room, or even a remote monitoring station. This feature is especially useful for providing the first-out logic determination to an operator or service technician, and for transmitting a service request. Also through the Link to Remote, any user inputs can be communicated to the digital signal processor 405. The Link to Remote output can be, as desired, an Ethernet or serial connection. Specifically, Device Net, Industrial Ethernet, MODBUS or RS- 232 communication protocols may be utilized. Beneficially, multiple digital signal processors 405, each associated with a single ignitor 200, can be serially connected, saving cabling costs. The present invention is not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the present invention in addition to those described herein will be apparent to those of skill in the art from the foregoing description and accompanying drawings. WE CLAIM : 1. A method for monitoring operation of a flame ignitor (200) having a flame rod (210) for igniting a flame within a combustion chamber, comprising : receiving one of (i) first input having a DC voltage of the flame rod (210) and (ii) second input having a plurality of start signals, each indicative of an operator instruction to activate the flame ignitor (200), and one or more flame proven signals, each indicative of a presence of a flame produced by the flame ignitor (200) responsive to a respective one of the plurality of start signals; if the first input is received, computing an AC voltage based upon the received first input, and determining if the flame rod (210) is dirty based on the computed AC voltage; and if the second input is received, determining, based upon the received second input, a reliability of the flame ignitor (200). 2. The method as claimed in claim 1, wherein: the computed AC voltage comprises an AC voltage waveform; and the computed AC voltage waveform is compared with an expected AC voltage waveform to determine if the flame rod (210) is dirty. 3. The method as claimed in claim 1 or 2, comprising: transmitting a signal indicative of the dirty flame rod (210) to at least one of (i) a control room associated with the combustion chamber, and (ii) a location remote from the control room, if the flame rod (210) is determined to be dirty. 4. The method as claimed in claim 3, wherein the remote location is associated with an entity responsible for servicing the flame ignitor (200). 5. The method as claimed in one of the preceding claims, wherein the reliability of the flame ignitor (200) is determined by dividing the number of the received flame proven signals by the number of received start signals to compute a result, and comparing the result to a reliability set point. 6. The method as claimed in one of the preceding claims further comprising : transmitting a warning signal, if the ingitor is determined to be unreliable, to at least one of (i) a control room associated with the combustion chamber, and (ii) a location remote from the control room. 7. The method as claimed in one of the preceding claims, wherein the DC voltage is a first DC voltage and the first input comprises a second DC voltage of the flame rod (210), and comprising: receiving third input having a fuel supply interruption signal and fourth input having an air supply interruption signal; and determining a cause of a failure of the flame ignitor (200) based upon a respective time at which each of the second DC voltage, fuel supply interruption signal and air supply interruption signal is received. 8. The method as claimed in claim 7, wherein the cause of the failure is determined based upon an earliest of the respective times. 9. The method as claimed in one of the preceding claims, comprising: displaying information indicative of the determination at the flame ignitor (200). 10. A system for monitoring operation of a flame ignitor (200) having a flame rod (210) for igniting a flame within a combustion chamber, comprising : a memory configured to store one of (i) first input having a DC voltage of the flame rod (210), and (ii) second input having a plurality of start signals, each indicative of an operator instruction to activate the flame ignitor (200), and one or more flame proven signals, each indicative of a presence of a flame produced by the flame ignitor (200) responsive to a respective one of the plurality of start signals; and a processor (405) configured to (i), if the first input is received, compute an AC voltage based upon the stored first input, and determine if the flame rod (210) is dirty based on the computed AC voltage, and (ii), if the second input is received, determine, based upon the stored second input, a reliability of the flame ignitor (200). 11. The system as claimed in claim 10, wherein. the computed AC voltage comprises an AC voltage waveform; and the computed AC voltage waveform is compared with an expected AC voltage waveform to determine if the flame rod (210) is dirty. 12. The system as claimed in claim 10 or 11, wherein : the processor (405) is configured to transmit a signal indicative of the dirty flame rod (210) to at least one of (i) a control room associated with the combustion chamber, and (ii) a location remote from the control room, if the flame rod (210) is determined to be dirty; and the remote location is associated with an entity responsible for servicing the flame ignitor (200). 13. The system as claimed in one of claims 10 to 12; wherein: the memory is configured to store a reliability set-point; and the processor (405) is configured to divide the number of stored flame proven signals by the number of stored start signals to compute a result, and to determine the reliability of the flame ignitor (200) by comparing the computed result to the stored reliability set point. 14. The system as claimed in one of claims 10 to 13, wherein: the processor (405) is configured to transmit a warning signal, if the flame ignitor (200) is determined to be unreliable, to at least one of (i) a control room associated with the combustion chamber, and (ii) a location remote from the control room. 15. The system as claimed in one of claims 10 to 15, wherein: the DC voltage is a first DC voltage; the stored first input includes a second DC voltage and a time associated with generation of the second DC voltage; the memory is configured to store a third input having a fuel supply interruption indicator and a time associated with generation of the fuel supply interruption indicator, and a fourth input having an air supply interruption indicator and a time associated with generation of the air supply interruption indicator; and the processor (405) is configured to determine a cause of a failure of the flame ignitor (200) based upon the stored respective times associated with the generation of the second DC voltage, the fuel supply interruption indicator, and the air supply interruption indicator. 16. The system as claimed in claim 15, wherein the cause of the failure is determined based upon an earliest of the stored times. 17. The system as claimed in one of the claims 10 to 16, further comprising: a display disposed at the flame ignitor (200) and configured to present information indicative of the determination. ABSTRACT "A method and system for monitoring operation of a flame ignitor" The present invention relates to a method and system for monitoring operation of a flame ignitor. Techniques for mentoring operation of a flame ignitor (200) are provided. In one embodiment, multiple inputs are received. The inputs are received from at least one of a first group of inputs and a second group of inputs. The first group includes a flame rod voltage, a stop signal for deactivation of the flame ignitor, a fuel supply interruption signal, and an air supply interruption signal. The second group includes a start signal for activation of the flame ignitor (200), and a flame proven signal indicating presence of a flame produced by the flame ignitor (200). If inputs from the first group are received, a cause of a failure of the flame ignitor (200) is determined. If inputs from the second group are received, a reliability of the flame ignitor (200) is determined.

Full Text

FIELD OF THE INVENTION
The present invention relates to an ignitor for a fossil fuel fired
combustion chamber, and more particularly to an ignitor having improved
performance and reliability.
BACKGROUND OF THE INVENTION
In order to begin the combustion process inside a fossil fuel fired
combustion chamber, such as that found in industrial and utility boilers, there
must be an energy source to begin the self-sustaining combustion reaction of
main fuel and air inside the combustion chamber Current practice is to use a
light fuel oil, natural gas, or propane ignitor of a size between input of 0.5 to
20 Million Btu/hr for each of several fuel admission compartments of the
combustion chamber.
Igniters have a dedicated fuel and air supply and an energy source,
typically a spark plug, to produce a flame. In operation, fuel and air are
introduced to the ignitor and a spark provides the energy to begin a self-
sustaining reaction that keeps the ignitor burning. Proof that the ignitor is
operating is established through the use of a flame detector, such as a flame
rod, a thermal sensing device, or an optical sensor, that is often integral with
the ignitor.
Once the ignitor is proven to be operating, main fuel and air for the
combustion chamber can be introduced, often after utilizing the ignitor to
preheat the combustion chamber. The energy from the ignitor (the ignitor
flame), allows the combustion reaction of the main fuel and air to begin.

Generally, once the main fuel and air is ignited the combustion reaction is
self-sustaining, and the ignitor can be turned off. However, in some cases,
such as due to low volatility of the main fuel, it is necessary to leave the
ignitor on in order to keep the main combustion reaction continuing. In other
cases, ignitors are left to burn continuously, as may be required by safety
laws.
For reasons of safety it is important that the ignitor reliably begin
burning on command, and that it be able to be confirmed that the ignitor is
producing a flame to insure the safe combustion of the main fuel and air.
Failure of an ignitor can result in unsafe accumulations of unburned main fuel
and air, resulting in massive explosive damage.
In one known type of coal-fired boiler unit, one or more relatively
high-capacity oil burners (warm-up guns) are started by one or more oil- or
gas-fired ignitors to preheat the combustion chamber Once the combustion
chamber has been brought up to the proper starting temperature, coal
nozzles are ignited by the oil- or gas-fired igniters, or by the warm-up guns
themselves.
At higher boiler loads, i.e., when the amount of coal supplied by the
coal nozzles is great, the combustion chamber can typically maintain stable
combustion of the pulverized coal. However, when the load goes down and
the coal supply is thereby decreased, the stability of the pulverized coal flame
is also decreased, and it is therefore common practice to use the igniters or
warm-up guns to maintain flame in the combustion chamber, thus avoiding
the accumulation of unburned coal dust in the combustion chamber and the
associated danger of explosion.

Certain portions of an ignitor mounted in a windbox compartment of
a combustion chamber are subjected to relatively high temperatures, typically
on the order of 500 degrees Fahrenheit or higher, in some conventional
igniters, there is a risk that an ignitor wire supplying energy to an ignitor spark
element may burn up due to the high temperatures, especially when
insufficient cooling air is supplied to the ignitor. Recently, a gas-fired ignitor
overcoming this problem has been proposed. However, oil-fired igniters are
still subject to this problem. Accordingly, a need exists for an oil-fired ignitor
which provides a reliable spark action and which has improved survivability in
a high temperature environment.
An igniter's spray of fuel and air (the combustive mix) is produced
by an atomizer. The spray produced by conventional atomizers used in oil-
fired igniters frequently has too many large droplets, resulting in insufficient
oxygen at the base of the flame. An insufficient amount of oxygen results in
excessive smoke formation, resulting in an unacceptable opacity from the
stack. Accordingly, a need exists for an oil-fired igniter that produces a spray
with more available oxygen at the flame base.
Introduced above, conventional igniters, no matter the type of
igniter fuel utilized, include some sort of flame sensing device which may be
mechanical or optical. The output of such a flame sensing device is
transmitted to a control room where operational decisions are made based
upon the sensed flame. If no igniter flame is detected when one is expected
to be present, repair personnel must service the non-performing igniter based
upon only the information that a flame is not present. Lack of a flame could
be due to any one of a faulty igniter fuel supply, a faulty igniter compressed
air, or a faulty igniter spark source. Further, a flame could actually be

present, and the flame detector itself could be sending a false lack of flame
signal. Currently, there is no way for service personnel to know what ignitor
component has failed without physically examining that igniter. Thus, many
man-hours are spent attempting to determine the reason an igniter has failed.
If repair personnel had an indication of a reason for failure prior to beginning a
repair operation, many of those man-hours could be saved. Accordingly, a
need exists for an igniter which provides information indicating which
component has failed.
Aside from an ignitor failure, routine scheduled maintenance of
igniters is typically performed in an effort to prevent failure. A single utility
boiler typically can include upwards of 64 individual igniters that must be
maintained. Performing this routine maintenance is both costly and time
consuming. That is, each ignitor, whether functioning properly or not, is
regularly inspected. If those igniters that required service could be identified,
not only could the time and cost expenses of services all igniters be saved,
but costs associated with ignitor failure, such as boiler down time, could be
saved. Accordingly, a need exists for an ignitor in which the necessity of
service can be determined prior to failure.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide an oil-fired ignitor
having reliable spark action in a high temperature environment.
It is another object of the present invention to provide an oil-fired
ignitor having an improved atomizer.

Another object of the present invention is to provide an ignitor
having higher reliability than conventional igniters.
Still another object of the present invention is to provide an igniter
in which an indication of which component, or components, are responsible
for an igniter failure is available.
Yet another object of the present invention is to provide an igniter in
which the necessity of service can be determined prior to an igniter failure.
The above-stated objects, as well as other objects, features, and
advantages, of the present invention will become readily apparent from the
following detailed description which is to be read in conjunction with the
appended drawings.
SUMMARY OF THE INVENTION
Methods and systems for monitoring operation of a flame igniter are
provided herein. The flame igniter is used to begin and/or support the
combustion process inside a fossil fuel fired combustion chamber. A system
includes at least a memory and a processor. A processor can be any type of
processor capable of functioning to implement the techniques described
herein. A memory can be any type of memory capable of storing information
and communicating with a processor.
In a first embodiment of the present invention, multiple inputs from
at least one of a first group of inputs and a second group of inputs are
received. That is, the multiple inputs could all come from the first group,

could all come from the second group, or come from a mixture of the first and
second groups.
The first group of inputs includes a flame rod voltage, a stop signal
for deactivation of the flame igniter, a fuel supply interruption signal, and an
air supply interruption signal. A flame rod voltage measures the intensity of
flame, with the voltage being proportional to the intensity of the flame. A stop
signal causes the flame ignitor to cease operation. A fuel supply interruption
signal indicates that the fuel supply for the flame igniter has been interrupted,
and an air supply interruption signal indicates that the air supply for the flame
igniter has been interrupted. The second group of inputs includes a start
signal for activation of the flame igniter and a flame proven signal indicating
presence of a flame produced by the flame ignitor A start signal causes the
flame ignitor to begin operation. A flame proven signal indicates that the
ignitor is successfully operating, i.e., producing a flame
If inputs from the first group are received, a determination of a
cause of a failure of the flame ignitor is made. This determination is made
based upon the received inputs from the first group If inputs from the second
group are received, a determination of the reliability of the flame ignitor is
made. This reliability determination is made based upon the received inputs
from the second group. It should be understood that inputs from both groups
may be received.

In one aspect of this first embodiment, information associated with
one or more determinations made based upon the received inputs is
transmitted. This could include a single transmission, or multiple
transmissions. Further, a transmission could be, as desired, made to a single
entity, or multiple entities. Also, a transmission could be a scheduled
transmission, could be made whenever a determination is made, or could be
made ad hoc.
In a further aspect, the information associated with a determination
is transmitted to at least one of a control room associated with a combustion
chamber with which the flame ignitor is associated, and a location remote
from the control room. In an even further aspect, the remote location is
associated with an entity responsible for servicing the flame ignitor. The
responsible entity could be an entity other than the entity to which the
combustion chamber belongs.
In another aspect of this first embodiment, multiple start signals and
multiple flame proven signals are received. Each received input is stored.
The number of stored flame proven signals is divided by the number of stored
start signals to determine the reliability of the flame ignitor.
In a further aspect, a warning signal is transmitted when the
determined reliability violates a reliability set-point. That is, if the determined
reliability does not meet a predetermined criteria, a warning signal is
transmitted. This transmission could be to the control room, could be to a
remote location, could be to another location, or could be to multiple
locations.

According to still another aspect of this embodiment multiple inputs
from group one are received. An indication of each received input from group
one is stored. This indication identifies the particular type of group one input
received. Also, a time that each group one input is received is stored. The
cause of failure is determined based, at least in part, upon the stored time
information. In a further aspect, the cause of failure is determined based
upon the first received group one input.
In yet another aspect of the first embodiment, information
associated with one or more determinations is outputted via a display on the
flame ignitor. That is, the flame ignitor has a display that is configured to
show information associated with at least one determination that has been
made based upon the multiple received inputs. This information could be
related to one, or both of, a cause of failure of the flame ignitor and a
reliability of the flame ignitor.
According to a second embodiment for monitoring operation of a
flame scanner, multiple inputs that are each associated with operation of the
flame scanner are received. An operational parameter of the flame ignitor is
then determined based upon one or more of the received inputs In one
aspect of this second embodiment, the determined operational parameter is
one of a cause of a failure of the flame ignitor, and a reliability of the flame
ignitor.
In another aspect of the flame ignitor, each input is one of a flame
rod voltage, a stop signal for deactivation of the flame ignitor, a fuel supply
interruption signal, an air supply interruption signal, a start signal for activation
of the flame ignitor, and a flame proven signal, each discussed above.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
In order to facilitate a fuller understanding of the present invention,
reference is now made to the appended drawings. These drawings should
not be construed as limiting the present invention, but are intended to be
exemplary only.
Figure 1 a schematic plan view of a fossil fuel-fired furnace having
a preferred embodiment of the ignitor of the present invention installed
thereon.
Figure 2 is a simplified depiction of an oil-fired ignitor in accordance
with one aspect of the present invention.
Figure 3 is a simplified depiction of processing electronics in
accordance with certain aspects of the present invention for use with an
ignitor.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
Referring now to the drawings, and more particularly to Figure 1,
there is depicted a conventional fossil fuel-fired power generation system,
generally designated by the reference numeral 10, having installed therein a
preferred embodiment of the igniter of the present invention. It should be
understood that the ignitor of the present invention could be utilized in.
industrial or utility installations other than that depicted in Figure 1 The fossil
fuel-fired power generation system 10 includes a fossil fuel-fired steam
generator 12 and an air preheater 14.

The fossil fuel-fired steam generator 12 includes a burner region. It
is within the burner region 16 of the fossil fuel-fired steam generator 12 that
the combustion of fossil fuel and air, in a manner well-known to those skilled
in this art, is initiated. To this end, the fossil fuel-fired steam generator 12 is
provided with a conventional firing system 18.
The firing system 18 includes a housing, preferably in the form of a
windbox 20. The windbox 20 includes a plurality of compartments, each
designated 22. In conventional fashion, some of the compartments 22 are
designed to function as fuel compartments from which fossil fuel is injected
into the burner region 16, while others of the compartments 22 are designed
to function as air compartments from which air is injected into the burner
region 16. The fossil fuel is supplied to the windbox 20 by a conventional fuel
supply means, not shown in the interest of maintaining clarity of illustration in
the drawing. At least some of the air which is injected into the burner region
16 for purposes of effecting combustion of the injected fuel is supplied to the
windbox 20 from the air preheater 14 through the duct 24.
It is within the burner region 16 of the fossil fuel-fired steam
generator 12 that the combustion of the fossil fuel and air is initiated The hot
gases that are produced from this combustion of the fossil fuel and air rise
upwardly in the fossil fuel-fired steam generator 12. During the upwardly
movement thereof in the fossil fuel-fired steam generator 12, the hot gases, in
a manner well-known to those skilled in this art, give up heat to fluid flowing
through tubes (not shown in the interest of maintaining clarity of illustration in
the drawing) that in conventional fashion line all four of the walls of the fossil
fuel-fired steam generator 12. Then, the hot gases flow through the horizontal
pass 26 of the fossil fuel-fired steam generator 12, which in turn leads to the

rear gas pass 28 of the fossil fuel-fired steam generator 12. Although not
shown in Figure 1, it should be understood that the horizontal pass 26 would
commonly have suitably provided therein some form of a heat transfer
surface. Similarly, heat transfer surface, as illustrated at 30 and 32, is suitably
provided within the gas pass 28. During passage through the rear gas pass
28 the hot gases give up heat to the fluid flowing through the tubes of the heat
transfer surface.
Upon exiting from the rear gas pass 28 of the fossil fuel-fired steam
generator 12 the hot gases are conveyed to the air preheater 14. To this end,
the fossil fuel-fired steam generator 12 is connected from the exit end 34
thereof to the air preheater 14 by means of duct work 36. After passage
through the air preheater 14, the now relatively cooler hot gases are further
conducted to conventional treatment apparatus which are not illustrated in the
interest of clarity.
The fossil fuel-fired steam generator 12 is provided with a preferred
embodiment of the ignitor of the present invention. Figure 2 shows an oil-
fired igniter 200 mounted in one of the windboxes of the fossil fuel-fired steam
generator 12. It should be understood that the fossil fuel-fired steam
generator 12, as well as any other industrial or utility installation, can be
provided with any desired number of the ignitor of the present invention The
ignitor 200 is mounted inside a pipe 201 secured to a windbox wall 205. The
ignitor 200 includes a conventional flame rod 210, a spark extension
assembly 215, a compressed air conduit 225, a fuel conduit 230 collinear and
disposed within the compressed air conduit 225, a bluff body 240 disposed at
the terminus of the compressed air conduit 225, and an atomizer 235
disposed within the bluff body 240.

The spark extension assembly 215 includes a solid conductor with
an outer ceramic insulation coating, enabling the spark extension assembly
215 to survive temperatures greater than 1000 degrees Fahrenheit. The solid
conductor, preferably made of stainless steel, though it could be any other
conductive metal, connects to an external electrical power source (not shown
in the Figures) at terminus 255. At the opposite end of the spark extension
assembly 215 is a high energy ignitor tip 220. The solid conductor receives
electrical current from the power source and conducts the electrical current to
the high energy ignitor tip 220, which produces a spark to ignite a spray
mixture of the compressed air and fuel released by the atomizer 235. United
States Patent Number 6,582,220, assigned to the assignee of the present
invention and which is incorporated herein in its entirety, discloses an
elongate electrode assembly suitable for use as the spark extension
assembly 215.
The external power source provides a high energy pulse of
electricity to the spark extension assembly 215. Preferably, the pulse is 12
joules for a microsecond pulse period, though other high energy levels and/or
pulse periods could be provided by the external power supply Because of
the high energy pulse, any unburned fuel and combustion products that have
accumulated on the high energy ignitor tip 220 are removed by the resultant
spark. Thus, degradation of the performance of the spark extension
assembly 215 due to build up is prevented.
The spark from the high energy ignitor tip 220 is positioned in the
output spray of the atomizer 235. The spark ignites the compressed air/fuel
spray produced by the atomizer 235. The configuration of the atomizer 235
allows additional compressed air to come straight out of the center of the

atomizer 235 into the central core of the spray to improve the fuel to air ratio.
This feature results in an increased amount of oxygen at the flame base,
which reduces opacity.
The bluff body 240 is spherical, or essentially spherical, with a
truncated face. The spherical shape minimizes air flow friction losses and
permits substantially greater mass flow of air through the pipe 201, which in
turn allows proper fuel mixing for a greater amount of fuel for combustion.
United States Patent Number 6,443,728, assigned to the assignee of the
present invention and which is incorporated herein in its entirety, discloses a
structure suitable for use as the bluff body 240.
In operation, the flame rod 210 is charged to approximately 40 volts
DC, allowing for an optimum signal-to-noise ratio. As flame ions interact with
the flame rod 210, the voltage dips and rises. These voltage fluctuations are
measured by sensor 265. The measured voltage is transmitted to processing
electronics, to be discussed below.
With reference to Figure 3, the processing electronics 400, which
can, as desired, be housed proximate to or remote from the ignitor 200,
include a digital signal processor 405 and a memory 410. The digital signal
processor 405 communicates with the memory 410. As desired, and as
shown in Figure 3, the digital signal processor 405 and the memory 410 may
be combined into a single unit. The digital signal processor 405 is preferably
of a minimum specification of 16-bit design operating at 40 million instructions
per second, however other designs could be utilized, as desired It should be
understood that the control electronics shown in Figure 3 and described
below can be utilized with igniters burning any type fuel, not just the oil-fired

ignitor 200 shown in Figure 2.
The digital signal processor 405 includes multiple inputs for
receiving information and multiple outputs for communicating the received
information and determined information to operators and service technicians.
The inputs include the flame rod voltage sensed by sensor 265 discussed
above, a start/stop signal input, a fuel flow switch input, and an air pressure
switch input The start/stop signal input is associated with signals generated
in the control room indicating a desire to activate or deactivate the ignitor 200.
That is, whenever an operator attempts to start the ignitor 200, a start signal
is received at the digital signal processor 405, and whenever an operator
stops the ignitor 200, a stop signal is received at the digital signal processor
405. Indications of these start and stop signals are stored in the memory 410
by the digital signal processor 405, along with a time each was received.
These stored indications will be further discussed below.
The fuel flow switch input receives signals from a fuel line sensor
(not shown in the Figures) on a fuel line to the ignitor 200. Whenever fuel
flow is interrupted, or decreases below a certain level, the fuel line sensor
sends a fuel flow warning signal to the digital signal processor 405. A fuel
flow warning signal causes a trip of the -gnitor 200. In a trip, as well as in an
operator-ordered shut down, the igniter's fuel, air, and spark are discontinued,
causing the ignitor flame to extinguish. The digital signal processor 405
stores an indication of the fuel flow warning signal in the memory 410, along
with the time such was received.

The air pressure switch input receives signals from a compressed
air line sensor (not shown in the Figures) on a compressed air line to the
ignitor 200. Whenever compressed air flow is interrupted, or decreases
below a certain level, the compressed air line sensor sends a air flow warning
signal to the digital signal processor 405. An air flow warning signal also
causes a trip of the ignitor 200. The digital signal processor 405 stores an
indication of the air flow warning signal in the memory 410, along with the
time such was received.
The memory also stores trip set points associated with the sensed
flame intensity on the flame rod 210. If the DC voltage measured by sensor
265 and input to the digital signal processor 405 violates a trip set point, the
digital signal processor 405 trips the ignitor 200. The digital signal processor
405 also calculates an AC voltage based upon the input DC voltage from
sensor 265. Likewise, if the calculated AC voltage violates a trip set point, the
digital signal processor 405 trips the ignitor 200. Whenever the ignitor 200 is
tripped due to violation of a set point, an indication of such, along with the
time, is stored in the memory 410 by the digital signal processor 405.
Separate from the trip set point processing described above, the
sensed DC voltage and the calculated AC voltage is available as a real-time
output, shown as Flame Intensity AC & DC output. A related output is the
Ignitor Proven output. This output is a state-based output. That is, if the
sensed DC voltage and the calculated AC voltage do not violate a set point, a
high signal is output Whereas, if one or both of the AC and DC voltages
violates a set point, a low signal is output. Outputs will be further discussed
below.

Also based upon the sensed flame rod DC voltage and calculated
flame rod AC voltage is the Flame Rod Dirty/Shorted output. This output is
also a state-based output. If the flame rod 210 is operating property, the
Flame Rod Dirty/Shorted output will be high. However, if the sensed DC
voltage falls to zero, or another stored value that indicates a shorted flame
rod, the Flame Rod Dirty/Shorted output will be low. Also, the digital signal
processor 405 monitors the calculated AC voltage. Stored in the memory 410
is an indication of an expected AC voltage waveform. If the calculated AC
voltage does not match the expected AC voltage waveform, or deviates from
the expected AC voltage waveform more than an acceptable amount the
Flame Rod Dirty/Shorted output will be low.
The stored information based upon the received inputs discussed
above forms a first-out logic architecture. The first-out architecture aids in
determining why an operating igniter has failed. Whenever an ignitor trips, no
matter the cause, signals indicating improper fuel flow, improper air flow, and
improper voltage, as discussed above, will each be received. This is because
once an ignitor shuts down, fuel and air flow cease, causing the flame to
extinguish, which in turn causes the flame rod to detect a lack of a flame.
Because of stored time information associated with each of these variables,
the cause of the trip can easily be determined. It should be understood that
the stored time information could simply be ordering information, or could be
an actual time. As an example of the first-out logic, if the ignitor 200 trips
because of the an improper fuel flow, the stored indication of improper fuel
How will have the earliest time indication because the improper air flow signal
and the lack of voltage signal will be received subsequent to the improper fuel

flow signal. The digital signal processor 405 is programmed to determine
which of the stored signals associated with a particular failure was received
first and output this determination to an operator or service technician via the
First-Out Logic output.
Introduced above, an indication of each received start signal is
stored in memory 410. Also stored in memory 410 is an indication of each
actual start. Each time the digital signal processor 405 determines that the
flame rod detects a flame within a certain time period following receipt of a
start signal the digital signal processor 405 stores an indication of a
successful start in the memory 410. The number of received start signals and
the number of successful starts is the basis for determining reliability of the
ignitor. Thus, the digital signal processor 405 divides the number of
successful starts indicated in the memory 410 by the number of received start
signals indicated in the memory 410 to produce a percentage reliability
indication. This information is available via the % Reliability output.
The percentage reliability indication is especially useful in
determining degradation of the spark extension assembly 215, as this
component is most often associated with a failed start attempt. The digital
signal processor 405 is programmed to not only calculate the percentage
reliability, but also report a need for service based upon that information. As
desired, the digital signal processor 405 can be programmed to transmit a
service request when the calculated percentage reliability falls below a certain
set point, stored in memory 410. Alternatively, or perhaps in combination, the

digital signal processor 405 can be programmed to transmit a service request
when the calculated percentage reliability begins to trend downward, perhaps
even at a predetermined rate stored in the memory 410. A service request is
transmitted via a Link to Remote, to be discussed further below.
The digital signal processor 405 has a user interface through which
all outputs discussed above are available. The user interface includes a
backlit LED bargraph display for communicating each output. Thus, via the
display, an operator or service technician can view the DC and the AC flame
intensity and the percent reliability, as well as the Ignitor Proven and Flame
Rod Dirty/Shorted outputs. Especially beneficial, the digital signal processor-
determined cause of a trip is also available via the display. Also, the user
interface includes a user input, preferably password protected, through which
an operator or service technician can adjust the stored voltage trip set points
and the shorted voltage
Also shown in Figure 3 is the Link to Remote input/output Through
the Link to Remote, all outputs discussed above can be transmitted to a
remote location, such as a local control room, or even a remote monitoring
station. This feature is especially useful for providing the first-out logic
determination to an operator or service technician, and for transmitting a
service request. Also through the Link to Remote, any user inputs can be
communicated to the digital signal processor 405.

The Link to Remote output can be, as desired, an Ethernet or serial
connection. Specifically, Device Net, Industrial Ethernet, MODBUS or RS-
232 communication protocols may be utilized. Beneficially, multiple digital
signal processors 405, each associated with a single ignitor 200, can be
serially connected, saving cabling costs.
The present invention is not to be limited in scope by the specific
embodiments described herein. Indeed, various modifications of the present
invention in addition to those described herein will be apparent to those of
skill in the art from the foregoing description and accompanying drawings.

WE CLAIM :
1. A method for monitoring operation of a flame ignitor (200) having a flame
rod (210) for igniting a flame within a combustion chamber, comprising :
receiving one of (i) first input having a DC voltage of the flame rod (210)
and (ii) second input having a plurality of start signals, each indicative of
an operator instruction to activate the flame ignitor (200), and one or
more flame proven signals, each indicative of a presence of a flame
produced by the flame ignitor (200) responsive to a respective one of the
plurality of start signals;
if the first input is received, computing an AC voltage based upon the
received first input, and determining if the flame rod (210) is dirty based
on the computed AC voltage; and
if the second input is received, determining, based upon the received
second input, a reliability of the flame ignitor (200).
2. The method as claimed in claim 1, wherein:
the computed AC voltage comprises an AC voltage waveform; and
the computed AC voltage waveform is compared with an expected AC
voltage waveform to determine if the flame rod (210) is dirty.
3. The method as claimed in claim 1 or 2, comprising:
transmitting a signal indicative of the dirty flame rod (210) to at least one
of (i) a control room associated with the combustion chamber, and (ii) a
location remote from the control room, if the flame rod (210) is
determined to be dirty.

4. The method as claimed in claim 3, wherein the remote location is
associated with an entity responsible for servicing the flame ignitor (200).
5. The method as claimed in one of the preceding claims, wherein the
reliability of the flame ignitor (200) is determined by dividing the number
of the received flame proven signals by the number of received start
signals to compute a result, and comparing the result to a reliability set
point.
6. The method as claimed in one of the preceding claims further comprising :
transmitting a warning signal, if the ingitor is determined to be unreliable,
to at least one of (i) a control room associated with the combustion
chamber, and (ii) a location remote from the control room.
7. The method as claimed in one of the preceding claims, wherein the DC
voltage is a first DC voltage and the first input comprises a second DC
voltage of the flame rod (210), and comprising:
receiving third input having a fuel supply interruption signal and fourth
input having an air supply interruption signal; and determining a cause of
a failure of the flame ignitor (200) based upon a respective time at which
each of the second DC voltage, fuel supply interruption signal and air
supply interruption signal is received.
8. The method as claimed in claim 7, wherein the cause of the failure is
determined based upon an earliest of the respective times.

9. The method as claimed in one of the preceding claims, comprising:
displaying information indicative of the determination at the flame ignitor
(200).
10. A system for monitoring operation of a flame ignitor (200) having a flame
rod (210) for igniting a flame within a combustion chamber, comprising :
a memory configured to store one of (i) first input having a DC voltage of
the flame rod (210), and (ii) second input having a plurality of start
signals, each indicative of an operator instruction to activate the flame
ignitor (200), and one or more flame proven signals, each indicative of a
presence of a flame produced by the flame ignitor (200) responsive to a
respective one of the plurality of start signals; and
a processor (405) configured to (i), if the first input is received, compute
an AC voltage based upon the stored first input, and determine if the
flame rod (210) is dirty based on the computed AC voltage, and (ii), if the
second input is received, determine, based upon the stored second input,
a reliability of the flame ignitor (200).
11. The system as claimed in claim 10, wherein.
the computed AC voltage comprises an AC voltage waveform; and
the computed AC voltage waveform is compared with an expected AC
voltage waveform to determine if the flame rod (210) is dirty.
12. The system as claimed in claim 10 or 11, wherein :
the processor (405) is configured to transmit a signal indicative of the
dirty flame rod (210) to at least one of (i) a control room associated with
the combustion chamber, and (ii) a location remote from the control

room, if the flame rod (210) is determined to be dirty; and the remote
location is associated with an entity responsible for servicing the flame
ignitor (200).
13. The system as claimed in one of claims 10 to 12; wherein:
the memory is configured to store a reliability set-point; and
the processor (405) is configured to divide the number of stored flame
proven signals by the number of stored start signals to compute a result,
and to determine the reliability of the flame ignitor (200) by comparing
the computed result to the stored reliability set point.
14. The system as claimed in one of claims 10 to 13, wherein:
the processor (405) is configured to transmit a warning signal, if the flame
ignitor (200) is determined to be unreliable, to at least one of (i) a control
room associated with the combustion chamber, and (ii) a location remote
from the control room.
15. The system as claimed in one of claims 10 to 15, wherein:
the DC voltage is a first DC voltage;
the stored first input includes a second DC voltage and a time associated
with generation of the second DC voltage;
the memory is configured to store a third input having a fuel supply
interruption indicator and a time associated with generation of the fuel
supply interruption indicator, and a fourth input having an air supply
interruption indicator and a time associated with generation of the air
supply interruption indicator; and

the processor (405) is configured to determine a cause of a failure of the
flame ignitor (200) based upon the stored respective times associated
with the generation of the second DC voltage, the fuel supply interruption
indicator, and the air supply interruption indicator.
16. The system as claimed in claim 15, wherein the cause of the failure is
determined based upon an earliest of the stored times.
17. The system as claimed in one of the claims 10 to 16, further comprising:
a display disposed at the flame ignitor (200) and configured to present
information indicative of the determination.

ABSTRACT

"A method and system for monitoring operation of a flame ignitor"
The present invention relates to a method and system for monitoring operation of a flame
ignitor. Techniques for mentoring operation of a flame ignitor (200) are provided. In one
embodiment, multiple inputs are received. The inputs are received from at least one of a
first group of inputs and a second group of inputs. The first group includes a flame rod
voltage, a stop signal for deactivation of the flame ignitor, a fuel supply interruption
signal, and an air supply interruption signal. The second group includes a start signal for
activation of the flame ignitor (200), and a flame proven signal indicating presence of a
flame produced by the flame ignitor (200). If inputs from the first group are received, a
cause of a failure of the flame ignitor (200) is determined. If inputs from the second
group are received, a reliability of the flame ignitor (200) is determined.

A METHOD AND SYSTEM FOR MONITORING OPERATION OF A FLAME IGNITOR

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