BURNER MONITOR

Abstract

For monitoring burner operation, such as in a refinery, boiler or the like, an acoustic sampler such as a piezo-electric microphone is located in a position to record an acoustic sample of the burner operation. The acoustic sample can be processed to determine whether the burner is operating normally or has suffered a flame out condition. Remedial actions can be undertaken to control the fuel supply to the burner if a flame out condition has been detected.

Description

FIELD OF THE INVENTION

The present invention relates to burners that produce a flame and to monitoring systems for detecting whether a flame is present and its condition.

BACKGROUND

In Oil Refineries and Petrochemical Plants, there are many types of furnaces available depending on the hydrocarbon being processed. Also, there are many types of burners available from many OEM's, that supply this industry.

One critical and common problem that occurs in refinery furnaces is flame instability. When a flame becomes unstable, it begins to flicker and this can lead to the flame being extinguished, known as “flame out”. In a flame out condition, the burner continues pumping unburned fuel into the furnace. Failure to correct this type of scenario is dangerous, since the unburned fuel in the furnace can lead to an explosion, which can damage equipment, cause probable losses in production, as well as endangerment to plant personnel. To solve this, it is necessary to make adjustments in the air registers or fuel supply, as soon as possible.

From simple, single cabin bottom fired heaters, to complex top fired reformers, all burners are subject to guidelines from authorities, such as the NPRA/API/CSB, in the use of flame detectors.

In power generation facilities that use boilers to generate steam/electricity, the same problems can occur.

There are two general methods of flame detection referred to as physical and optical. Both systems require constant maintenance and calibration. Physical flame detection typically uses a flame rod that is biased with high voltage, and is immersed in the flame when the burner is in service. Optical flame detection typically uses ultraviolet (UV) and infrared (IR) sensors that react to the radiation emitted from a flame. Hot refractory, as well as adjoining burners, generates a significant amount of IR/UV radiation that causes inconsistent readings causing false alarms.

What is required is an improved system, method and apparatus for monitoring a burner flame.

SUMMARY OF ONE OR MORE EMBODIMENTS OF THE INVENTION

Advantages of One or More Embodiments of the Present Invention

The various embodiments of the present invention may, but do not necessarily, achieve one or more of the following advantages:

the ability to detect flame out of a burner with improved accuracy;

the ability to detect flame out with reduced false alarms;

the ability to monitor and display operating conditions for a plurality of burners; and

the ability to monitor and display detailed operating conditions for a specific burner.

These and other advantages may be realized by reference to the remaining portions of the specification, claims, and abstract.

Brief Description of One or More Embodiments of the Present Invention

In one embodiment, there is provided a method for detecting an abnormal operation condition in at least one burner. In the method, a microphone or similar acoustic sampler obtains at least one acoustic sample of an operation of the at least one burner. The sample is passed to a processing system which processes the acoustic sample determine whether the at least one burner is operating abnormally.

In one embodiment, there is provided a system for detecting an abnormal operation condition in at least one burner. In the system, an acoustic sampler obtains at least one acoustic sample of an operation of the at least one burner. A processing system including at least one processor receives the acoustic sample and determines whether the at least one burner is operating abnormally.

In one embodiment, there is provided a measurement apparatus for measuring the operation of at least one burner. The measurement apparatus may include means for obtaining an acoustic sample from the at least one burner and electronic means for processing the acoustic sample to determine a current operating condition of the burner.

The above description sets forth, rather broadly, a summary of one embodiment of the present invention so that the detailed description that follows may be better understood and contributions of the present invention to the art may be better appreciated. Some of the embodiments of the present invention may not include all of the features or characteristics listed in the above summary. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining at least one preferred embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is substantially a schematic representation of a refinery heater/furnace;

FIG. 2 is substantially a schematic of a burner with acoustic sensor;

FIG. 3 is substantially a schematic of the process components of a process for obtaining and analyzing an acoustic signal from a burner;

FIG. 4 is substantially a perspective of an acoustic sensor unit;

FIG. 5 is substantially a perspective of a microphone and sphere mounting;

FIG. 6 is substantially a perspective of a mounting block;

FIG. 7 is substantially a perspective of a mounting plate;

FIG. 8 is substantially a depiction of a preamplifier block;

FIG. 9 is substantially a depiction of a preamplifier circuit;

FIG. 10 is substantially a depiction of a software interface;

FIG. 11 is substantially a depiction of a display showing details for multiple burners;

FIG. 12 substantially depicts a display showing details for a single burner during an ideal operation;

FIG. 13 substantially depicts a display showing details for a single burner during a non-optimized condition;

FIG. 14 substantially depicts a display showing details for a single burner during a flame out condition;

FIG. 15 substantially depicts a flowchart of a method for determining an abnormal operating condition of a burner;

FIG. 16 substantially depicts a corner of a boiler in perspective view;

FIG. 17 substantially depicts the corner of the boiler in a plan view;

FIG. 18 substantially depicts a perspective of the corner of the boiler with a wall section cut away to reveal the internal detail;

FIG. 19 substantially depicts a microphone probe;

FIG. 20 substantially depicts a perspective view of a heat shield;

FIG. 21 substantially depicts the heat shield over a microphone probe tip;

FIG. 22 substantially depicts a cut-away view of the FIG. 21;

FIG. 23 substantially depicts the heat shield disposed on a probe tip and connector;

FIG. 24 substantially depicts an alternative configuration for installing a microphone probe into a gas line of a burner of a boiler;

FIG. 25 substantially depicts a cut-away view of FIG. 24;

FIG. 26 substantially depicts a probe tip with rubber insulator disposed in a diffuser;

FIG. 27 substantially depicts a cut-away view similar to FIG. 26;

FIG. 28 substantially depicts a rigid microphone probe;

FIG. 29 substantially depicts a dual outlet, single burner with installed microphone probes;

FIG. 30 substantially depicts a microphone probe installed in a gas line of a single burner with an air purge of a gas line installed to allow online maintenance;

FIG. 31 substantially depicts the installation of FIG. 30 in a cut-away view;

FIG. 32 substantially depicts process electronics;

FIG. 33 substantially depicts a process flow; and

FIG. 34 substantially depicts an acoustic response of a microphone probe during different phases of burner operation.

DESCRIPTION OF CERTAIN EMBODIMENTS OF THE PRESENT INVENTION

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part of this application. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

The present invention utilizes an acoustic method to detect the presence or absence of a burner flame. It has been found by the present inventors, that an acoustic measurement of the burner operation, both in operating and flame out conditions, can be used to establish an acoustic profile of the burner that can in turn be used to indicate a flame out condition. The method may utilize an appropriate acoustic measurement device, such as the acoustic flame detector that is designed and manufactured by Scientific Environmental Instruments, Inc. The acoustic flame detector is coupled with spectral analysis software that uses the burner's noise to provide a precise condition of the burner flame. This method is impervious to the types of false alarms that are generated by other types of measurement.

A particular advantage of the acoustic method described herein is that in addition to detecting an absolute flame out condition, the method can also quickly detect many different abnormal operating conditions of the burner. Knowing the normal operation of the burner condition, any variable or change of the burner may be detected and displayed, as will be described in more detail below, allowing adjustments to be made either manually, automatically and/or programmatically.

In FIG. 1 there is schematically shown a refinery heater/furnace application 10 in which a series of burners 20 heat a space 14. A single burner system 20 of the series of burners is shown in FIG. 2. The burner includes fuel and air inlets and an area where the fuel and air mix and ignite. The particular construction of the burner is not pertinent to the present application and many different burner constructions will be apparent to the person skilled in the art.

Attached to the burner is an acoustic sensor unit 30. The acoustic sensor unit 30 may include a microphone, e.g. a piezo-electric microphone, such as the microphone manufactured by Scientific Environmental Instruments, Inc. While a piezo-electric microphone is shown and described, other acoustic sampling devices and methods may be apparent to the person skilled in the art. As shown in FIG. 3, the microphone unit 30 attached to the burner 20 listens to the noise produced by the flame 21 and sends an acoustic signal to a processing system of recording and analysis components. Knowing the normal operation of the burner condition, any variation or change of the burner can be displayed and/or trigger remedial actions.

In one embodiment, the recording and analysis components may include a preamplifier enclosure 40 that contains one or more preamplifiers for one or more burners, analog to digital converter (ADC) 42 and processor 44, such as a computer. The computer may be any suitable processing device, including, without limitation, a personal computer, laptop, tablet, mobile telephone executing an appropriate application, etc.

An acoustic sensor unit 30 is shown in more detail in FIGS. 4-7. The acoustic sensor unit 30 includes a microphone 32 that supports high temperatures (500° F.). The microphone 32 is coupled to a stainless steel sphere 34 (FIG. 5) via one or more threaded couplings.

The microphone and sphere may be connected to the burner via a mount that includes a mounting block 36 and a mounting plate 38. The mounting block 36 (FIG. 6) and plate 38 (FIG. 7) each have circular apertures 37, 39 of a diameter that is slightly less than the diameter of the sphere 34. The sphere 34 is partially received into the aperture 37 of the mounting block 36 and sandwiched between the plate 38 and the block 36. The plate 38 may be secured to the block via screws 33 or similar fasteners. When loosely secured, the sphere 34 can rotate in the mounting block 36 in three dimensions to orient the microphone 32 in any desired position and angle. When the plate 38 is tightened against the sphere 34, the position of the microphone 32 becomes fixed.

It should be noted that the particular configuration of the acoustic sensor unit 30 will be dependent upon the configuration and arrangement of the burner 20. Thus, while the acoustic sensor unit 30 is depicted suspended below the burner 20, the acoustic sensor unit may be mounted in other positions as required.

The sphere 34 allows orientation through two rotational axes (i.e. polar angle and azimuth) for the best coupling of burner noise. The components of the acoustic sensor unit may all be metal or similar materials that all support high temperatures without special cooling requirements.

Each microphone is coupled to a preamplifier. In one embodiment, several preamplifiers may be provided in a single preamplifier box or housing. In a specific example depicted in FIG. 8, a single preamplifier box 50 houses four preamplifiers 52 to allow up to 4 microphones with a radius of 20 feet to accommodate different burner positions. The preamplifier box 50 may be made of any suitable sturdy material, e.g. fiberglass.

Each preamplifier may include circuitry for amplifying the acoustic signals prior to processing. A sample preamplifier circuit is depicted in FIG. 9. After the preamplifier, the acoustic signals are passed through an ADC to enable the signals to then be received and processed by the computer system.

Software operating in the computer system receives the acoustic signals from each microphone and processes the signal at a range of frequencies to develop an operating profile of the burner. The operating profile can be compared to one or more stored profiles. The stored profiles may include normal operating profiles and/or profiles representing known abnormal operating conditions, such as flame out conditions, fuel rich or fuel lean mixtures, etc. Through the comparison, the software is able to determine if any burner is operating in an abnormal condition that requires adjustment or attention from an operator.

In one or more embodiments, the profiles may be stored as frequency profiles. In one or more embodiments, the profiles may be stored as processed signal values of the acoustic samples, e.g. root mean square (RMS), peak values, etc. In one or more embodiments, the profiles may be stored as values of one or more specific parameters. For example, the software may be able to process an acoustic frequency spectrum recorded by a burner microphone and through frequency profiling, calculate the temperature and the fuel/air ratio. These values can be compared to desired operating characteristics of the burner.

The stored profiles can be generated through a calibration procedure by recording acoustic signals during known and controlled operating conditions of the burner and/or series of burners.

Various formats can be used to display the operating conditions of the burner array. FIG. 10 shows an embodiment of a display 60. The software displays an interface 62 on the display 60 that illustrates the furnace 64 and all of the burners 66 within the furnace. A simple green indicator may indicate the associated burner is operating within its desired operating characteristics. Any burner that is operating abnormally may be indicated by a red indicator. More critical abnormal conditions may be accompanied by additional indicators such as flashing lights, audible alarms, etc. The operator may choose to see more detail of a burner through any suitable selection mechanism on the display, such as by cursor control device (mouse, pointer, etc) or through a touch screen interface.

FIG. 11 shows a more detailed interface 70 that indicates specific operating parameters for each of the burners on graphs. In one embodiment, the interface 70 may display the temperature and the fuel/air ratio. From the display of these parameters, an operator may be able to deduce the problem leading to the abnormal operating condition and either shut down a burner or adjust the inputs to the burner, such as one or both of the fuel supply or air supply, in order to affect the output of the burner. By making these adjustments, the operator can prevent costly losses to the plant as well as reducing potential high pollution emissions.

The fuel and air should be optimized to assure burner compliance in order to reduce emissions and generate high heat flux. Stoichiometric combustion is not the norm since it may lead to fuel rich/lean flames at certain burners. Excess air is important in order to be assured complete combustion. However, high amounts of excess air is costly. By providing continuous monitoring of the operation of each burner and displaying any non-optimized operating profiles as alarm conditions, the software described herein is able to assist in complying with regulations and furnace efficiency.

Each burner in the interface of FIG. 11 may be individually selectable to allow the operator to view further specific details of the burner. An individual burner display screen is depicted in FIG. 12. Interface 80 shows parameters for the burner including the burner identifier (number, name, location, etc) 82, the fuel supply rate 83, fuel/air ratio 84, flame temperature 85, time based charts 86 and an indicator of the burner status 87. The burner status 87 can be calculated from the flame temperature derived from the acoustic signals. The interface 80 shows the burner operating at its ideal or optimized levels.

FIG. 13 shows the interface 80 when the burner is operating in an abnormal or non-optimized condition. High flame luminosity is an indication of bad combustion. The flame will have high carbon content causing a yellow flame and the flame temperature will be less than ideal. The length of the flame will be higher, creating a possibility of flame impingement at the process tubes. In the display we can see burner identifier 82, in blue signaling wrong air/fuel ratio. The burner status 87 indicates a yellow flame condition, which the operator will understand as being a non-optimized condition.

FIG. 14 shows the interface 80 after the burner has suffered a flame out condition. The graphical depiction of the burner status 87 shows the burner as extinguished and the burner name 82 is shown in red. The charts 86 indicate the sudden temperature drop and the time at which the flame out condition occurred. This is an alarm condition of no flame on the burner. Fuel pressure is maintained to the other burners causing a possibility of a furnace explosion from the unburned fuel in the heater. By indicating the burner as having suffered an alarm condition, the operator is able to quickly deduce where the error condition has occurred and make adjustments as necessary to circumvent any potential hazards.

In addition to direct monitoring interfaces, the software is able to log the data and generate and display gas temperature measurement data in a number of highly effective and useful presentations that provide critical and timely temperature related information on the furnace, boiler or thermal process being monitored. The software presents operations and performance personnel with straightforward, yet powerful, visual information on current and historical gas temperatures. Spatial temperature distribution profiles (i.e. temperature as a function of position within a planar area), temperature/time trends, and average gas temperatures within user-defined zones are available. Both rectangular and circular planar geometry's may be supported.

FIG. 15 depicts a flowchart of a method for determining an abnormal operating condition for a burner. At step 101, an acoustic sampler obtains an acoustic sample around a burner during operation of the burner. At step 102, a processor receives the acoustic sample and then processes the sample to generate an operating profile for the burner (step 103). The operating profile may be an acoustic profile or may be processed further to a parameter profile that specifies one or more parameters of the current operating condition of the burner. The generated profile is compared to at least one stored profile (step 104) and a determination is made, from the comparison, as to whether the burner is operating in a normal or abnormal condition.

The specific embodiments above have been described with reference to a burner operation in a refinery/furnace application. The apparatus and methods are also applicable to gas and/or oil fired boilers. In one embodiment, a boiler may have several burners placed around the boiler, for example at the 4 corners and in different elevations. In a specific example, the lower burners are exclusively gas fired. The top burners are oil fired and in the center section they are dual fuel fired. Other boiler configurations will be apparent to the person skilled in the art.

FIG. 16 shows an example of a corner section of a boiler 200 having a burner. A portion of the outer wall structure is removed to reveal some of the internal detail. FIG. 17 shows the same corner section in plan view and FIG. 18 shows the same corner section in a partial perspective allowing the internal detail to be more clearly seen.

FIGS. 16-18 show a traditional arrangement for corner fired boilers. The burner arrangement includes a gas supply line 202 that supplies a gas from an inlet connection 204 and which ignites at the end of the supply line 206. A flame diffuser 208 disperses the gas for the flame appropriately. A traditional optical monitoring unit is disposed within a conduit 210 that runs through the outer wall structure and then adjacent to the gas supply line 202. The conduit 210 has a connector flange 212 at the inlet side. An air purge 214 is provided in the gas line 202 near the inlet connection 204.

In one embodiment, the optical monitoring unit may be removed. In its place, a microphone probe may be substituted. An embodiment of a microphone probe is shown in FIG. 19. The probe 250 includes the piezo-microphone tip 252. Connected to the piezo-microphone tip 252 is a flexible connector section 254 that connects at its opposite end to a rigid connector 256. At the end of the rigid connector 256 is a connection flange 258. Internal signal cabling 260 passes through the rigid and flexible connectors 256, 254 to the probe tip 252.

The microphone may be passed through the conduit until it is located at the end of the conduit 210 at a position where it is capable of recording an acoustic signal from the gas burner. The microphone probe 250 may be secured in place by securing the flange 258 of the probe assembly to the flange 212 of the conduit 210 using suitable fasteners, such as bolts and nuts, screws, etc.

In some applications, the proximity of the microphone tip 252 to the gas diffuser 208 and the high operational temperatures in this region may lead to operational failure of the microphone. If required, the microphone assembly 250 may be supplied with a heat shield 270 to protect the microphone from the harshest temperatures. An embodiment of a heat shield is depicted in FIGS. 20-23. FIG. 20 depicts the heat shield 270 in isolation. FIG. 21 depicts the heat shield over the piezo-tip 252 of the probe. FIG. 22 depicts a cut-away version of FIG. 21 and FIG. 23 depicts the heat shield installed over the probe tip and connector.

The radiation shield 270 includes first 272 and second 274 end rings. A plurality of plates 276 or braces extend between the first and second rings 272, 274 and provide a degree of shielding to the probe tip 252. The end ring 274 of the shield 270 has a length and internal circumference that accommodates the end tip of the piezo-element of the microphone.

Spring clips 278 may be secured to the inner ring 272 and extend back along the length of the connector 254. Wire, or similar may be provided around the clips 278 to secure the clips 278 onto the connector 254, thereby ensuring that the heat shield does not inadvertently slide off the probe and conducts heat from the tip 270 to the flexible hose 254.

The heat shield 270 may be made from suitable heat shielding materials, such as stainless steel, carbon steel coated ceramic material or the like.

The complete microphone probe, with optional heat shield, may be passed through the conduit traditionally provided for the optical monitoring equipment. The flange 258 connects to a similar connection flange 212 on the conduit 210. The length of the complete probe assembly 250 is configured so that when installed in the conduit 210, the probe tip 252 is disposed substantially adjacent to the flame diffuser 208 and so is able to record an acoustic signal at the burner.

FIG. 24 shows an alternative embodiment for addressing excessive heating of the probe tip 252. In this embodiment, the probe is not disposed in the optical monitoring conduit but is instead installed through the gas line 202 itself. As shown in FIG. 24, there is a straight section 282 of gas pipe from the diffuser 208 that then passes through a series a bends before the gas inlet 204. A conduit 283 may be run in a substantially straight line from a flange 284 at an inlet through the wall structure to the elbow 286 at the start of the straight section 282 and through the straight section 282 of the gas line to the diffuser 208. The probe tip 252 can be passed in a substantially straight line to the diffuser 208. The probe tip 252 is therefore deployed in a region in which the gas from the supply line is expanding. It is believed that this gas expansion will have a cooling effect on the probe tip. In one embodiment, it is believed that the probe tip can be kept to less than 60 F, which is considerably less than the 200 F+ which is typically encountered at the standard opening for Optical Flame Detectors.

FIG. 25 is a partial cut-away version of FIG. 24 which shows the probe passing through the additional conduit 283, into the straight section 282 of the gas line and with the probe tip 252 deployed in the diffuser 208. The probe tip 252 may optionally be provided with the heat shield 270 as described above, though in many embodiments, the cooling effect of the gas may render the heat shield unnecessary. FIG. 26 shows an alternative probe tip having a rubber or other material for vibration insulation 290 that isolates the probe tip 252 from the internal wall of the gas line 282. FIG. 27 shows the same probe tip in a cut-away view. Because the conduit 283 is configured to provide a straight line to the diffuser 208, the microphone probe 250 does not require a flexible connector section and may be made using only a rigid connector section. An example of a rigid microphone probe is depicted in FIG. 28. The rigid probe includes a probe tip 252, rigid connector section 256 and connector flange 258.

FIG. 29 shows the connection system of FIGS. 24 and 25 disposed in a dual discharge burner with an upper 292 and lower 294 gas line. FIG. 29 further depicts the upper connection microphone probe conduit 298 and lower microphone probe conduit 296.

If it is not possible or practical to run an extra conduit through the wall structure to the straight section of the gas line stemming from the diffuser, in an alternative embodiment, the microphone probe may be run through the gas line via the air purge port. An embodiment of this configuration is depicted in FIGS. 30 and 31. The microphone tip and flexible connector may be passed through a central aperture of the flange 302 of the air purge line 214 using the rigid connector portion 256 to manipulate the insertion of the flexible connector section 254 and probe tip 252. The flange 258 of the microphone probe may engage the air purge flange 302 to secure the microphone probe in place. FIG. 31 shows additional detail of how the rigid connector section connects to the flange 258 while providing an internal channel 259 for the signal cabling (not shown).

The microphone probe 250 connects to a control box that may be located on the exterior of the wall structure of the boiler. The control box may house electronics units for a multiple burners. The control box may further connect to a computer system that receives the signals from each electronics units and amalgamates the results for presentation on a suitable interface and/or for controlling monitoring alerts and alarms.

In FIG. 32, there is shown a block diagram of components of the control box. Each unit 320 includes a microphone sensor 250 as herein described that is disposed within the boiler to record acoustic signals from a single burner. Signal cabling from the microphone sensor connects to a charge amplifier 322 and bandpass filter 324. A programmable amplifier 326 allows gain adjustments and tuning of the system to the particular burner and avoid interference from other burners in the system. The output of the programmable amplifier 326 passes to an Analogue to Digital Converter (ADC) 328 and then to a microcontroller unit (MCU) 330. The MCU 330 provides the internal control of the electronics unit, gain adjustments etc. A communications module 332 such as an RS485 serial controller allows external commands to flow into the unit from a central computer 334 located elsewhere as well as data and responses to flow out of the unit to the computer 334 and/or other control systems. A power supply 336 within the electronics unit 320 provides power to all of the local components of the respective unit 320. The electronics unit 320 may be replicated for as many burners as required with all units 320 communicating with the same computer 334 or multiple computers.

FIG. 33 shows a process flowchart 400 for operating the control unit of FIG. 32. The process 400 is conducted primarily by the MCU 330. The process includes an initialization sequence of hardware initialization 401, reading the set threshold 402, and setting the amplifier gain 403. This ensures proper signal to noise ratios and tunes the control unit to the particular burner being monitored. Initialization further includes starting the ADC time acquisition interrupt 404 which causes the control unit to periodically sample, and starting the communications interrupt 405 which periodically checks for incoming process commands. After initialization, the control unit enters a sampling loop. The system is set to sample for a set length of time. If the check at step 406 determines that this sampling length has not yet been met, the MCU checks the communications interrupt (step 407) for incoming command signals. If no commands are detected, then the system iterates and returns to step 405. Otherwise, the commands are processed (step 408) and handled accordingly.

Once the sample length has been acquired, the recorded sample can be processed. In one embodiment, the sample is analyzed to calculate an RMS signal value 409 for the detected sample which is then further analyzed 410 to determine how the burner performance is trending. At step 411, a decision is made as to whether the burner is operating within allowable parameters or should be turned off or controlled in some manner. For example, the trend analysis may indicate a flame out or other abnormal condition which may lead to turning off the fuel supply to the burner.

FIG. 34 shows an example of the response of the microphone probe tip over an approximately 45 second time period in a controlled sequence in which the burner was On-Off-On. In the period 0-6 seconds of the initial burner On period, the signal 342 is relatively high. In the burner Off period from 6-37 seconds, the burner generates little noise and thus the microphone response 344 is relatively low. In the second burner On period from 37-45 seconds, the microphone response 346 is relatively high once again. By processing these signals to calculate an RMS value across a sampling period of say, 50 msec to 250 msec, at 15 khz or higher, it can be determined when the RMS value is at a low level that would indicate that the burner has gone out. Alerts can then be sent to management systems and/or can be used to control safety valves to shut off the fuel flow to the respective burner, control air flows, etc.

In one embodiment, the MCU of the electronics unit may be programmed to determine whether the measured signal level is indicative of an abnormal operation condition of the burner and may pass alerts and control signals through the communications module. Alternatively, the MCU may pass the signal level or the raw sample data through the communications module to the computer where it is processed and analyzed. Thus, the MCU and computer may together be considered as a processing system.

Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the embodiments of this invention. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents rather than by the examples given.

Claims

1. A method for detecting an abnormal operation condition in at least one burner, the method comprising: (A) obtaining, by at least one microphone, at least one acoustic sample of an operation of the at least one burner;(B) passing the at least one acoustic sample from the at least one microphone to a processing system comprising at least one processor;(C) processing, by the processing system, the at least one acoustic sample; and(D) determining, by the processing system from at least one processed acoustic sample, whether the at least one burner is operating abnormally.

2. The method of claim 1 comprising: (A) generating an operating profile of the at least one burner from the at least one processed acoustic signal;(B) comparing, by the processing system, the generated operating profile with at least one stored profile; and(C) determining, by the processing system from the comparison, whether the at least one burner is operating abnormally.

3. The method of claim 1 comprising, when it is determined that the at least one burner is operating abnormally, automatically switching off a fuel supply to the at least one burner.

4. The method of claim 1 wherein processing the at least one acoustic sample comprises calculating a Root Mean Square (RMS) value of the at least one acoustic sample.

5. The method of claim 1 comprising providing a heat shield over the at least one microphone.

6. The method of claim 1 comprising disposing the at least one microphone in a gas supply line to the at least one burner.

7. The method of claim 6 wherein gas expansion at a region where the at least one microphone is disposed provides a cooling effect to the at least one microphone.

8. A system for detecting an abnormal operation condition in at least one burner comprising: (A) at least one microphone that obtains an acoustic sample of an operation of the at least one burner;(B) at least one processor that is programmed to: (a) receive the acoustic sample;(b) process the at least one acoustic sample to a processed signal; and(c) determine from the processed signal whether the at least one burner is operating abnormally.

9. The system of claim 8 comprising at least one microphone probe, the microphone probe comprising: (A) the at least one microphone; and(B) at least one connector connected to the at least one microphone;(C) wherein the at least one microphone probe is configured to dispose the at least one microphone adjacent the at least one burner.

10. The system of claim 8 wherein the at least one microphone probe is disposed in an optical monitoring conduit.

11. The system of claim 8 comprising wherein the at least one microphone probe is at least partially disposed in a gas supply line of the at least one burner.

12. The system of claim 11 wherein the at least one microphone is disposed such that expanding gas within the gas supply line provides a cooling effect to the at least one microphone.

13. The system of claim 8 comprising a computer interface for displaying a current operating state of the at least one burner.

14. The system of claim 8 comprising at least one mount for mounting the at least one microphone to the at least one burner, wherein the at least one mount allows the orientation of the microphone to be adjusted.

15. The system of claim 14 wherein the mount comprises at least a partial spherical section that provides for orientation of the microphone through at least two rotational axes.

16. The system of claim 8 comprising at least one heat shield disposed over the at least one microphone.

17. The system of claim 8 wherein the at least one microphone comprises at least one piezo-electric microphone.

18. A measurement apparatus for measuring the operating condition of at least one burner, the measurement apparatus comprising: (A) microphone means for obtaining an acoustic sample from the at least one burner; and(B) electronic means for processing the at least one acoustic sample to determine a current operating condition of the at least one burner.

19. The measurement apparatus of claim 18 comprising probe means for locating the at least one microphone means adjacent the at least one burner.

20. The measurement apparatus of claim 18 comprising mount means for mounting the at least one microphone means to the at least one burner.

21. The measurement apparatus of claim 18 comprising means for determining a signal level of the at least one acoustic sample and determining whether the signal level indicates an abnormal operating condition of the at least one burner.

22. The measurement apparatus of claim 18 comprising interface means for displaying an operating condition of the at least one burner.