Method of cavitation/flashing detection in or near a process control valve
First Claim
1. An apparatus for sensing cavitation in fluid flowing through a flow control device, the apparatus comprising:
- an acoustic emission sensor configured to be disposed along a controlled fluid flow path extending through a body of the flow control device at a first selected location, wherein the acoustic emission sensor is arranged to detect acoustic signals produced by cavitation within the fluid flow path and to provide acoustic information based on the detected acoustic signals; and
a processor operatively coupled with the acoustic emission sensor and arranged to receive the acoustic information from the acoustic emission sensor, wherein the processor is arranged to process the acoustic information and monitor cavitation levels in the fluid flow path at least partly based on a rate of cavitation events and an intensity of individual cavitation events extracted from the acoustic information,wherein the processor differentiates between different flow conditions in the fluid flow path, including between a normal flow condition and a cavitation flow condition above a predefined threshold cavitation level, and generates a report of the flow condition in the fluid flow path.
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Accused Products
Abstract
A system and apparatus for detecting and monitoring cavitation inside a flow control device, such as a control valve, includes an acoustic emission sensor coupled to the flow control device in a manner to acquire acoustic signals caused by cavitation. A processor receives acoustic information from the acoustic emission sensor. The processor selectively identifies cavitation events from the acoustic information that meet certain predefined criteria. Cavitation levels are monitored based on at least one of a rate of cavitation events and intensity of individual cavitation events. The cavitation levels may be used to identify the presence of cavitation in the flow control device, to track accumulated cavitation in the flow control device, and/or to identify significant changes in the cavitation levels over time. This information may be used to reduce cavitation, estimate repair and maintenance, and/or monitor performance of the flow control device.
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Citations
24 Claims
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1. An apparatus for sensing cavitation in fluid flowing through a flow control device, the apparatus comprising:
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an acoustic emission sensor configured to be disposed along a controlled fluid flow path extending through a body of the flow control device at a first selected location, wherein the acoustic emission sensor is arranged to detect acoustic signals produced by cavitation within the fluid flow path and to provide acoustic information based on the detected acoustic signals; and a processor operatively coupled with the acoustic emission sensor and arranged to receive the acoustic information from the acoustic emission sensor, wherein the processor is arranged to process the acoustic information and monitor cavitation levels in the fluid flow path at least partly based on a rate of cavitation events and an intensity of individual cavitation events extracted from the acoustic information, wherein the processor differentiates between different flow conditions in the fluid flow path, including between a normal flow condition and a cavitation flow condition above a predefined threshold cavitation level, and generates a report of the flow condition in the fluid flow path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of monitoring cavitation levels in a flow control device for process liquids, wherein an acoustic emission sensor is coupled to an exterior wall of the flow control device and a processor is operatively coupled to the acoustic emission sensor to receive acoustic emission signals representative of transient acoustic energy data sensed in the fluid flow path by the acoustic emission sensor, the method comprising:
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acquiring signals from the acoustic emission sensor with the processor; determining if the acquired signals correspond to a cavitation event having predefined characteristics; recording selected characteristics of the acquired signals with the processor only if the acquired signals are produced by a cavitation event; and determining the cavitation level from the recorded selected characteristics, the cavitation level being determined based on a rate of cavitation events and an intensity of each cavitation event. - View Dependent Claims (13, 14, 15, 16)
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17. A method of monitoring an estimate of damage to a flow control device for process liquids caused by cavitation, wherein an acoustic emission sensor is coupled to an exterior wall of the flow control device and a processor is operatively coupled to the acoustic emission sensor to receive acoustic emission signals representative of transient acoustic energy data sensed in the fluid flow path by the acoustic emission sensor, the method comprising:
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acquiring signals from the acoustic emission sensor with the digital signal processor, wherein the acquired signals are associated with transient acoustic emission data within a pre-defined range of frequencies; recording selected characteristics of the acquired signals with the digital signal processor only if the acquired signals are produced by a cavitation event wherein the acquired signals are within a predefined filter range; calculating, from the recorded selected characteristics, a hit rate comprising the number of cavitation events that occur within a selected period of time; calculating, from the recorded selected characteristics, an intensity of each cavitation event, the intensity comprising an energy unit per cavitation event; determining a cavitation level based on the hit rate and the intensity; and tracking an accumulation over time that the cavitation level exceeds a predetermined threshold, whereby an estimate of accumulated damage to the flow control device caused by cavitation may be monitored. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A method of monitoring whether cavitation levels in a flow control device for process liquids are increasing, wherein an acoustic emission sensor is coupled to an exterior wall of the flow control device and a digital signal processor is operatively coupled to the acoustic emission sensor to receive acoustic emission signals representative of transient acoustic energy data sensed in the fluid flow path by the acoustic emission sensor, the method comprising:
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acquiring signals from the acoustic emission sensor with the digital signal processor, wherein the acquired signals are generated in response to transient acoustic emission data within a pre-defined range of frequencies; recording selected characteristics of the acquired signals with the digital signal processor only if the acquired signals are produced by a cavitation event wherein the acquired signals are within a predefined filter range; calculating, from the recorded characteristics, a hit rate comprising the number of cavitation events that occur within a period of time; calculating, from the recorded characteristics, an intensity of each cavitation event, the intensity comprising an energy unit per cavitation event; calculating a trend of the hit rates and intensities with respect to time; and generating an alert that cavitation levels are increasing if the trend indicates that the hit rates and intensities are increasing over time. - View Dependent Claims (24)
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Specification