The present invention generally involves a system and method for monitoring the health of a compressor. More specifically, the present invention describes a system that combines acoustic energy sensors with statistically significant operational information to monitor the compressor, detects stress waves or other acoustic energy caused by compressor anomalies, and/or provides information reflective of the health of the compressor.
Compressors are widely used in industrial and commercial operations. For example, a typical gas turbine includes an axial compressor at the front, one or more combustors around the middle, and a turbine at the rear. The compressor includes a compressor casing that encloses multiple stages of rotating blades and stationary vanes. Ambient air enters the compressor, and the rotating blades and stationary vanes progressively impart kinetic energy to the working fluid (air) to bring it to a highly energized state. The working fluid exits the compressor and flows to the combustors where it mixes with fuel and ignites to generate combustion gases having a high temperature, pressure, and velocity. The combustion gases exit the combustors and flow to the turbine where they expand to produce work.
During operations, internal compressor components are continuously subjected to wear from corrosion, erosion, and foreign object debris entrained in the working fluid. High cycle fatigue may lead to the formation of cracks and other anomalies in the internal compressor components, such as corrosion of a stator vane or increased rubbing or friction between the rotor and stationary parts. Once formed, the cracks and other anomalies tend to propagate, increasing the risk that an internal compressor component may break apart or fail during operations, cause serious damage to personnel and equipment, and require extended shut down periods to repair or replace the damaged components.
Conventional systems and methods exist to monitor the performance and operation of compressors. For example, vibration sensors may be used to monitor vibrations from the compressor during operations. A change in the frequency or magnitude of existing vibrations may indicate excessive wear and/or crack formation. However, vibration sensors may only detect cracks and other anomalies that are large enough to cause an imbalance and vibration in the compressor. As a result, vibration sensors may not detect small cracks that do not result in a detectable vibration in the compressor.
Visual inspections are also used to monitor the performance and operation of compressors. For example, the compressor may be shut down and the casing may be removed to allow a visual examination of discrete locations inside the compressor. However, the visual inspections are time consuming, are limited to visually accessible components, require the compressor to be shut down, and can only detect existing cracks that are large enough to be visually discernable.
Therefore, it would be desirable to have an improved system and method for monitoring the performance and operation of a compressor that avoids some or all of the disadvantages associated with vibration detectors and visual detection.
Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.
One embodiment of the present invention is a system for monitoring compressor anomalies. The system includes an acoustic energy detector connected to the compressor and a controller in communication with the acoustic energy detector. The acoustic energy detector transmits an acoustic energy signal reflective of acoustic energy produced by the compressor to the controller. The system further includes at least one sensor connected to the compressor, and the at least one sensor measures an operating parameter of the compressor and transmits a parameter signal reflective of the operating parameter to the controller.
Another embodiment of the present invention is a system for monitoring compressor anomalies. The system includes an acoustic energy detector connected to the compressor, and the acoustic energy detector includes a sensor connected to an amplifier. The system further includes a controller in communication with the acoustic energy detector, and the acoustic energy detector transmits an acoustic energy signal reflective of acoustic energy produced by the compressor to the controller. At least one sensor connected to the compressor measures an operating parameter of the compressor and transmits a parameter signal reflective of the operating parameter to the controller,
The present invention also includes a method for monitoring compressor anomalies. The method includes sensing acoustic energy produced by the compressor and transmitting an acoustic energy signal reflective of the acoustic energy to a controller. The method further includes sensing at least one operating parameter of the compressor, transmitting a parameter signal reflective of the operating parameter to the controller, and transmitting an output signal based on the acoustic energy signal and the operating parameter signal.
Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.
A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.
Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
The statistically significant information may include, for example, real-time information from sensors 22 connected to the compressor 12, historical information about the compressor 12 operations, repairs, and/or maintenance, and/or historical information about the operations, repairs, and maintenance of similar compressors. The output signal 16 may indicate, for example, an alarming condition requiring immediate attention, a suggested or modified inspection interval, a suggested or modified repair or maintenance schedule, and/or crack length information.
As shown in
The acoustic energy wave or shock wave may be produced, for example, by an anomaly in the compressor such as the initiation and/or propagation of a crack, corrosion of a stator vane, or rubbing between the rotor and stationary parts. The shock wave may be characterized as having one or more peak waves of approximately equal magnitude with subsequent secondary waves having a decreasing amplitude. The electrical signal 36 from the sensor(s) 26 may reflect information about the shock wave, such as the number, duration, frequency, time, and/or magnitude of the peak waves and/or the secondary waves. The filter 40 may include a predetermined threshold to modify the electrical signal 26 by removing background noise from the electrical signal 26 that does not exceed the predetermined threshold. The filter 40 then passes the filtered signal 46 to the amplifier 42. In particular embodiments, the filter 40 may include a frequency band pass filter that may be tuned or adjusted to screen particular frequencies of noise from the electrical signal 36 produced by the sensor(s) 26. In addition or alternately, the filter 40 may employ a process commonly referred to as binning to combine the electrical signals 36 from multiple sensors 26 and enhance the clarity of the acoustic energy signal 44 transmitted to the controller 14.
Referring back to
The input device 54 allows a user to communicate with the system 10 and may include any structure for providing an interface between the user and the system 10. For example, the input device may include a keyboard, computer, terminal, tape drive, and/or any other device for receiving input from a user and generating a data signal 62 to the system 10.
The data signal 62 may include any available information about the compressor 12 and associated equipment 56, 58 stored in a database for use by the controller 14. For example, the data signal 62 may include fleet information collected about similar compressors and associated equipment that includes operational, repair, and/or maintenance information of statistical and historical significance. The data signal 62 may also include historical information about the particular compressor 12 and associated equipment 56, 58, such as the date and duration of previous operating levels, particular equipment configurations during previous operations, completed maintenance items, empirical test results, etc. The data signal 62 may also include prospective or forecasted events for the compressor 12 and associated equipment 56, 58, based on the fleet models, such as anticipated operating levels, equipment configurations, scheduled maintenance, compressor failure risk, and the predicted end-of-life for various components. The data signal 62 may also include programming modifications that the user desires to implement in the controller 14. For example, empirical data may become available that suggests a change in the fleet model used to predict crack initiation and/or propagation, rubbing events, and other compressor anomalies. As a result, the user may desire to alter the predetermined threshold, inspection and/or maintenance intervals, or other parameters programmed into the controller 14, and the user can communicate the changed programming to the controller 14 through the data signal 62 generated by the input device 54.
The parameter signal(s) 60 and data signal 62 from the parameter sensor(s) 22 and input device 54, respectively, may be transmitted to one or more data storage devices 20 via a wired or wireless communication network. Each data storage device 20 may be a computer memory storage device, for example, a hard drive, an optical disk, or a magnetic tape. The data storage device(s) 20 may be part of an on-site monitoring system integral to and/or local to the controller 14, as shown in
During operations, the controller 14 employs a sensor and information fusion technique to determine the operational status of the compressor 12. Specifically, the controller 14 receives the acoustic energy signal 44, one or more parameter signals 60, and any additional information provided by the user through the data signal 62. The controller 14 combines and filters all of this information to reach conclusions and recommendations about the operation and maintenance of the compressor 12. For example, the controller 14 may identify a crack initiation and/or propagation event in the compressor 12 based solely on a specific frequency and/or amplitude included in the acoustic energy signal 44. The controller 14 may further pinpoint the exact location of the suspected crack in the compressor 12 based on the time delay, frequency, magnitude, or any other characteristic of the acoustic energy signal 44.
Oftentimes, however, the useful information in the acoustic energy signal 44 may be obscured by noise from normal operating conditions or sporadic, but recurring events, thus limiting the ability of the controller 14 to reliably identify the onset or propagation of a crack or anomaly in the compressor 12. To improve the signal-to-noise ratio of the acoustic energy signal 44, the controller 14 may be programmed to apply known mathematical techniques to the acoustic energy signal 44, parameter signals 60, and/or data signal 62. For example, the controller 14 may be programmed to include, for example, Wavelet filter, a temporal Fast Fourier Transform (FFT), a chaotic series, frequency demodulation, a correlation integral, Bayesian statistics, etc. to identify time-series relationships between the acoustic energy signal 44, the parameter signals 60, and/or the data signal 62. The controller 14 may then retrieve empirical data from a memory storage device 20 or look up table that associates, for example, a particular crack size or location to an anticipated growth rate and ultimate component failure. The controller 14 may then fuse the time-series relationships with the empirical data to identify or predict upcoming events, such as stator vane cracking, compressor rubbing, casing cracking, excessive wear in rotating vanes, etc. Additional classification techniques, such as supervised and unsupervised techniques, may supplement the controller to classify acoustic emission events and anomalies.
As shown in
The system 10 illustrated in
In additional embodiments, the method for monitoring the performance of the compressor 12 or anomalies in the compressor 12 may include filtering the acoustic energy signal 44 based on the predetermined threshold and further filtering based upon the operating mode of the compressor 12 and associated equipment 56, 58. These operating modes may be calculated by using compressor and gas turbine operating parameters included in the parameter signal 60 and/or data signal 62. Still further embodiments may include transmitting the data signal 62 that reflects information about the compressor 12 from the input device 54 to the controller 14.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.