Compressor Valve Health Monitor
First Claim
1. A valve monitor for use with a rotating machine having a plurality of valves and a rotating element, the valve monitor comprising:
- a plurality of valve sensors detecting at least vibration, each valve sensor uniquely associated with one of the valves, each valve sensor measuring vibrations at the associated valve and generating a vibration signal;
a tachometer associated with the rotating element of the rotating machine to measure rotation of the rotating element; and
a signal processing module in communication with each valve sensor and the tachometer, the signal processing module including a frequency filter operable to remove low frequency components below a selected frequency from the vibration signal to produce a filtered vibration signal, the signal processing module operable to;
correlate the vibration signal with an angular position corresponding to the rotation of the rotating element;
apply a stress wave analysis to digital data representing the filtered vibration signal from a selected valve to produce analyzed data corresponding to flow turbulence at the selected valve; and
generate a circular waveform representing the flow turbulence at the selected valve based on the analyzed data.
1 Assignment
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Accused Products
Abstract
A rotating machine valve health monitor. Aspects of the valve monitor include instrumenting each valve of a reciprocating compressor, or other rotating machine, with a sensor capable of detecting at least vibration and instrumenting the crank shaft with a sensor capable of detecting at least rotation. A controller directly monitors the operation and condition of each valve to precisely identify any individual valve exhibiting leakage issues rather than only identifying the region of the leakage. The valve monitor uses a relatively high frequency stress wave analysis technique to provide a good signal-to-noise ratio to identify impact events indicative of leakage. The valve monitor uses circular waveforms of vibration data for individual valves to identify leakage by pattern recognition or visual identification. The valve monitor provides ongoing data collection to give warning of predicted valve failure and scheduling of preventative maintenance for failing valves.
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Citations
20 Claims
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1. A valve monitor for use with a rotating machine having a plurality of valves and a rotating element, the valve monitor comprising:
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a plurality of valve sensors detecting at least vibration, each valve sensor uniquely associated with one of the valves, each valve sensor measuring vibrations at the associated valve and generating a vibration signal; a tachometer associated with the rotating element of the rotating machine to measure rotation of the rotating element; and a signal processing module in communication with each valve sensor and the tachometer, the signal processing module including a frequency filter operable to remove low frequency components below a selected frequency from the vibration signal to produce a filtered vibration signal, the signal processing module operable to; correlate the vibration signal with an angular position corresponding to the rotation of the rotating element; apply a stress wave analysis to digital data representing the filtered vibration signal from a selected valve to produce analyzed data corresponding to flow turbulence at the selected valve; and generate a circular waveform representing the flow turbulence at the selected valve based on the analyzed data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of directly monitoring individual valves of a compressor having multiple cylinders, a piston associated with each cylinder, and a crankshaft driving the pistons, each cylinder comprising a cylinder head having a plurality of valves, the method comprising the acts of:
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uniquely associating, with each valve, a valve sensor measuring at least vibrations; measuring an analog vibration signal from each valve sensor; converting each analog vibration signal into digital vibration data; for each valve; removing low frequency vibration components from the digital vibration data; analyzing the digital vibration data using a high frequency stress wave analysis technique to generate analyzed digital vibration data; generating a circular waveform based on the analyzed digital vibration data corresponding to the valve; and determining a health for each valve based on one or more peaks appearing in the circular waveform. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A valve monitor for use with a reciprocating compressor having multiple valves operatively driven by a crankshaft, the valve monitor comprising:
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a valve sensor uniquely associated with one of the valves for measuring vibrations at the associated valve and producing a vibration signal based thereon; a tachometer associated with the crankshaft to measure rotation of the crankshaft; a signal processing module in communication with each valve sensor and the tachometer, the signal processing module including a frequency filter operable to remove low frequency components below a frequency of at least about 5 kHz from the vibration signal to produce a high frequency vibration signal, the signal processing module operable to; correlate the vibration signal with an angular position corresponding to the rotation of the crankshaft; monitor trends in the vibration signal in relation to alarm limits; perform stress wave analysis using the high frequency vibration signal from the valve to produce analyzed data corresponding to the flow turbulence at the valve when the high frequency vibration signal is outside alarm limits; and generate a circular waveform representing the flow turbulence at the selected valve based on the analyzed data; and a health processing module in communication with the signal processing module, the health processing module operable to; assess valve health of the valve based on a comparison of current operating parameters of the valve to corresponding baseline parameters of the valve using the circular waveform; identify the valve as failing when the current operating parameters are out of tolerance relative to the corresponding baseline parameters; predict a failure time for the valve based on a rate of change of the current operating parameters relative to previous operating parameters; and generate an alarm indicating the predicted failure time in advance of actual failure of the valve.
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Specification