Abstract: Engine health monitoring is used to assess the health of an engine, such as a gas turbine engine. Blades mounted on a shaft produce a modal response when excited. The shaft has an order related component that varies with the rotational velocity of the shaft. Modal responses are increased when the natural frequency range of the selected blade mode intersects with one of the order related components. By applying a short time chirp-Fourier transform with a frequency speed that is a function of a rate of change in the rotational velocity of the shaft a selected signal can be isolated. Cracks in the blades can be detected from the isolated signal.

Abstract: Engine health monitoring is used to assess the health of an engine, such as a gas turbine engine. Blades mounted on a shaft produce a modal response when excited. The shaft has an order related component that varies with the rotational velocity of the shaft. Modal responses are increased when the natural frequency range of the selected blade mode intersects with one of the order related components. By applying a short time chirp-Fourier transform with a frequency speed that is a function of a rate of change in the rotational velocity of the shaft a selected signal can be isolated. Cracks in the blades can be detected from the isolated signal.

Abstract: Engine health monitoring is used to assess the health of an engine, such as a gas turbine engine. Blades mounted on a shaft produce a modal response when excited. The shaft has an order related component that varies with the rotational velocity of the shaft. Modal responses are increased when the natural frequency range of the selected blade mode intersects with one of the order related components. By applying a short time chirp-Fourier transform with a frequency speed that is a function of a rate of change in the rotational velocity of the shaft a selected signal can be isolated. Cracks in the blades can be detected from the isolated signal.

Abstract: A method and apparatus for detecting an abnormality in e.g. in operating characteristics or function of a machine, apparatus or system, the method including providing a data sample set comprising n values of a measured physical parameter associated with the apparatus or system generated by repeating a measurement of the physical parameter n times. An extremal measured parameter value is selected from amongst the data sample set, determining a probability of observing the selected parameter value (e.g. of observing a value not exceeding the selected parameter value) by applying the selected parameter value to an extreme value probability distribution function having a location parameter and a scale parameter. The value of the location parameter and the value of the scale parameter are each constructed using an integer value m (e.g. notionally representing the size of a sub-sample data set comprising m of said measured parameter values) in which m is less than n (i.e. m<n).

Abstract: A method of analysing tachometer and vibration response data from an apparatus having one or more rotary components is provided. The method comprises the steps of: providing vibration response data and corresponding tachometer data from the apparatus for a period over which a rotary component of the apparatus varies in rotational speed, the tachometer data being for that component; repeatedly performing at intervals throughout the period the sub-steps of: determining a forcing frequency of the component from the tachometer data and a corresponding vibration response frequency of the apparatus from the vibration response data, comparing the forcing and vibration response frequencies to determine the relative phase difference between the frequencies, and determining the corresponding amplitude of the vibration response from the vibration response data; and plotting the relative phase differences and vibration amplitudes on a polar diagram.

Abstract: A method and apparatus for detecting an abnormality in e.g. in operating characteristics or function of a machine, apparatus or system, the method including providing a data sample set comprising n values of a measured physical parameter associated with the apparatus or system generated by repeating a measurement of the physical parameter n times. An extremal measured parameter value is selected from amongst the data sample set, determining a probability of observing the selected parameter value (e.g. of observing a value not exceeding the selected parameter value) by applying the selected parameter value to an extreme value probability distribution function having a location parameter and a scale parameter. The value of the location parameter and the value of the scale parameter are each constructed using an integer value m (e.g. notionally representing the size of a sub-sample data set comprising m of said measured parameter values) in which m is less than n (i.e. m<n).

Abstract: Engine health monitoring is used to assess the health of an engine, such as a gas turbine engine. Blades mounted on a shaft produce a modal response when excited. The shaft has an order related component that varies with the rotational velocity of the shaft. Modal responses are increased when the natural frequency range of the selected blade mode intersects with one of the order related components. By applying a short time chirp-Fourier transform with a frequency speed that is a function of a rate of change in the rotational velocity of the shaft a selected signal can be isolated. Cracks in the blades can be detected from the isolated signal.

Abstract: A method for measuring fluid flow rates comprises the steps of: (a) creating a non-oscillating magnetic field of a predetermined strength across a flowing fluid; (b) performing the sub-steps of: (i) exposing the flowing fluid to an oscillating magnetic field pulse orthogonal to the non-oscillating magnetic field to generate an NMR signal, and (ii) detecting the NMR signal from the flowing fluid in the form of a free induction decay; and (c) determining the fluid flow rate from the initial magnitude of the free induction decay.

Abstract: Novel tracked orders (i.e., tracked orders that are not present in “healthy” machinery) are useful for locating bearing anomalies. Accordingly, a method for locating bearing anomalies in machinery is provided that includes receiving vibration measurements acquired from the machinery, analyzing the vibration measurements to identify novel tracked orders indicative of bearing anomalies, and ascertaining the location of a bearing anomaly by relating a novel tracked order thus-identified to one or more further tracked orders. Thus, the novel tracked order does not merely indicate the occurrence of a bearing anomaly, but, in combination with the one or more further tracked orders, allows the bearing anomaly to be traced to a particular position.

Abstract: A method for filtering spurious resonances from an NMR dataset comprises the steps of: (a) creating a first, non-oscillating magnetic field of a predetermined field strength across a sample, (b) intermittently exposing the sample to a second, oscillating magnetic field orthogonal to the first to generate an NMR signal, (c) detecting the NMR signal from the sample, (d) adjusting the first magnetic field to a different predetermined field strength and repeating steps (a) to (c), and (d) comparing the detected signals to obtain an NMR dataset from the sample from which spurious resonances have been filtered.

Abstract: A method of analysing tachometer and vibration response data from an apparatus having one or more rotary components is provided. The method comprises the steps of: providing vibration response data and corresponding tachometer data from the apparatus for a period over which a rotary component of the apparatus varies in rotational speed, the tachometer data being for that component; repeatedly performing at intervals throughout the period the sub-steps of: determining a forcing frequency of the component from the tachometer data and a corresponding vibration response frequency of the apparatus from the vibration response data, comparing the forcing and vibration response frequencies to determine the relative phase difference between the frequencies, and determining the corresponding amplitude of the vibration response from the vibration response data; and plotting the relative phase differences and vibration amplitudes on a polar diagram.

Abstract: Novel tracked orders (i.e., tracked orders that are not present in “healthy” machinery) are useful for locating bearing anomalies. Accordingly, a method for locating bearing anomalies in machinery is provided that includes receiving vibration measurements acquired from the machinery, analyzing the vibration measurements to identify novel tracked orders indicative of bearing anomalies, and ascertaining the location of a bearing anomaly by relating a novel tracked order thus-identified to one or more further tracked orders. Thus, the novel tracked order does not merely indicate the occurrence of a bearing anomaly, but, in combination with the one or more further tracked orders, allows the bearing anomaly to be traced to a particular position.

Abstract: A method for measuring fluid flow rates comprises the steps of: (a) creating a non-oscillating magnetic field of a predetermined strength across a flowing fluid; (b) performing the sub-steps of: (i) exposing the flowing fluid to an oscillating magnetic field pulse orthogonal to the non-oscillating magnetic field to generate an NMR signal, and (ii) detecting the NMR signal from the flowing fluid in the form of a free induction decay; and (c) determining the fluid flow rate from the initial magnitude of the free induction decay.

Abstract: A method for filtering spurious resonances from an NMR dataset comprises the steps of: (a) creating a first, non-oscillating magnetic field of a predetermined field strength across a sample, (b) intermittently exposing the sample to a second, oscillating magnetic field orthogonal to the first to generate an NMR signal, (c) detecting the NMR signal from the sample, (d) adjusting the first magnetic field to a different predetermined field strength and repeating steps (a) to (c), and (d) comparing the detected signals to obtain an NMR dataset from the sample from which spurious resonances have been filtered.

Abstract: Novel tracked orders (i.e., tracked orders that are not present in “healthy” machinery) are useful for locating bearing anomalies. Accordingly, a method for locating bearing anomalies in machinery is provided that includes receiving vibration measurements acquired from the machinery, analyzing the vibration measurements to identify novel tracked orders indicative of bearing anomalies, and ascertaining the location of a bearing anomaly by relating a novel tracked order thus-identified to one or more further tracked orders. Thus, the novel tracked order does not merely indicate the occurrence of a bearing anomaly, but, in combination with the one or more further tracked orders, allows the bearing anomaly to be traced to a particular position.

Abstract: A method for monitoring the health of a system comprises performing at each of a plurality of times the steps of: constructing a condition signature from a plurality of condition indicators including (a) a plurality of vibration measurements acquired from the system or (b) one or more vibration measurements and one or more performance parameter measurements acquired from the system; predicting a normal signature from a model defining one or more inter-dependencies between said condition indicators, the normal signature corresponding to the condition signature for a healthy system; comparing the condition signature with the normal signature; and registering an event if the condition signature differs from the normal signature by more than a predetermined threshold.

Abstract: A method for monitoring the health of a system comprises performing at each of a plurality of times the steps of: constructing a condition signature (30) from a plurality of condition indicators including (a) a plurality of vibration measurements acquired from the system or (b) one or more vibration measurements and one or more performance parameter measurements acquired from the system; predicting a normal signature (32) from a model defining one or more inter-dependencies between said condition indicators, the normal signature corresponding to the condition signature for a healthy system; comparing the condition signature with the normal signature; and registering an event if the condition signature differs from the normal signature by more than a predetermined threshold.

Abstract: A method and system for detecting an anomaly in a fluid system, comprising exposing a sample of the fluid system to a first, non-oscillating magnetic field, simultaneously exposing the sample to a second, oscillating magnetic field orthogonal to the first field, modulating one or both of the magnetic fields, and detecting and capturing a resulting NMR signal from the sample. An analysis of the captured signal, typically involving transformation of the signal into an NMR frequency domain spectrum, can be performed to look for specific changes in the signal indicative of the presence of a particular anomaly.

Abstract: A method for monitoring the health of a system comprises performing at each of a plurality of times the steps of:

Abstract: A method and system for detecting an anomaly in a fluid system, comprising exposing a sample of the fluid system to a first, non-oscillating magnetic field, simultaneously exposing the sample to a second, oscillating magnetic field orthogonal to the first field, modulating one or both of the magnetic fields, and detecting and capturing a resulting NMR signal from the sample.