Method and apparatus for diagnosing and controlling rotating stall and surge in rotating machinery
First Claim
1. A diagnostic and corrective method to avert stall in a bearing supported rotating machine having a fluid throughput, the steps including:
- monitoring deflection of a shaft about which the machine rotates;
comparing the deflection with a standard, andaltering the deflection of the shaft as the machine approaches a stall when indicated by the comparison step.
1 Assignment
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Accused Products
Abstract
A method and apparatus is provided for diagnosing and correcting rotating stall and surge in rotating machines by monitoring dynamic shaft precession and comparing this precession with a standard and altering the precession as the machine approaches a destabilizing condition when indicated by the comparison step. Axial vibration monitoring means is also provided for monitoring and comparing a dynamic axial vibration of the machine with a standard and altering the axial vibration as the machine approaches a destabilizing condition. Furthermore, the instant invention measures the complex dynamic stiffness of the machine and computes the direct dynamic stiffness and the quadrature dynamic stiffness for use as a destabilizing warning device by monitoring for a drop in direct dynamic stiffness and/or a coincidence of zero crossing of both the direct dynamic stiffness and the quadrature dynamic stiffness components. One embodiment for altering the rotating stall and/or surge is by a controlled active servobearing.
49 Citations
33 Claims
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1. A diagnostic and corrective method to avert stall in a bearing supported rotating machine having a fluid throughput, the steps including:
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monitoring deflection of a shaft about which the machine rotates; comparing the deflection with a standard, and altering the deflection of the shaft as the machine approaches a stall when indicated by the comparison step. - View Dependent Claims (2, 3)
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4. A diagnostic and corrective method to avert stall in a bearing supported rotating machine having a fluid throughput, the steps including:
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monitoring deflection of a shaft about which the machine rotates wherein the step of monitoring shaft deflection includes monitoring machine vibration including frequency thereof; monitoring rotative speed of the shaft; comparing the deflection with a standard wherein the comparison step further includes the step of computing a direct dynamic stiffness component of the machine, and altering the deflection of the shaft as the machine approaches a stall when indicated by the comparison step. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for tuning a rotating machine to preclude stall, the steps including:
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inducing a stall into the machine to determine stall characteristics for the machine having a rotating shaft; recording the stall characteristics including rotating shaft precession leading up to at least the stall condition; monitoring the machine against the recorded stall characteristics, and correcting machine parameters prior to inception of a subsequent stall.
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15. A method for tuning a rotating machine to preclude stall, the steps including:
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inducing a stall into the machine to determine stall characteristics for the machine; calculating the nonsynchronous dynamic stiffness by filtering a forward rotor response component to a frequency of an input perturbation force for a plurality of different speeds; recording the stall characteristics leading up to at least the stall condition; monitoring the machine against the recorded stall characteristics, and correcting machine parameters prior to inception of a subsequent stall. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A stall preclusion apparatus, comprising in combination:
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a rotating machine including a shaft; monitoring means operatively coupled to said rotating machine and including means for monitoring shaft precession correlative to machine vibration; means to vary a machine parameter operatively coupled to the machine, and processing means interposed between said monitoring means and said means to vary said machine parameter to enable said means to vary said machine parameter upon indication from said monitoring means of a prestall condition. - View Dependent Claims (23, 24, 25)
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26. A stall preclusion apparatus, comprising in combination:
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a rotating machine including a shaft; monitoring means operatively coupled to said rotating machine wherein said monitoring means includes means for monitoring lateral shaft precession wherein said lateral shaft precession monitoring means includes a pair of orthogonal eddy current displacement transducers operatively coupled to the machine to measure said lateral shaft precession; means to vary a machine parameter operatively coupled to the machine, and processing means interposed between said monitoring means and said means to vary said machine parameter to enable said means to vary said machine parameter upon indication of a prestall condition wherein said processing means includes a data acquisition and reduction system operatively coupled to said pair of orthogonal eddy current displacement transducers for collecting, storing and reducing vibration data correlative to lateral shaft precession, and wherein said monitoring means further includes means for monitoring axial shaft vibration. - View Dependent Claims (27, 28)
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29. An apparatus for diagnosing and controlling rotating stall in rotating machinery, said apparatus comprising in combination:
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means for sensing raw dynamic machine vibration signals correlative to shaft precession; means for comparing said signals with a paradigm of machine stall conditions; means for altering shaft precession as the machine approaches a stall condition when indicated by the comparison step.
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30. A diagnostic and corrective method to avert stall in a bearing supported rotating machine having a fluid throughput, the steps including:
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monitoring deflection of a shaft about which the machine rotates; computing a direct dynamic stiffness component of the machine; altering the deflection of the shaft as a function of a drop in said direct dynamic stiffness component. - View Dependent Claims (31)
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32. A diagnostic and corrective method to avert stall in a bearing supported rotating machine having a fluid throughput, the steps including:
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monitoring deflection of a shaft about which the machine rotates; comparing the deflection with a standard wherein the comparison step further includes the step of computing a dynamic stiffness component of the machine, and altering the deflection of the shaft as the machine approaches a stall when indicated by the comparison step.
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33. A stall preclusion apparatus, comprising in combination:
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a rotating machine including a shaft; monitoring means operatively coupled to said rotating machine wherein said monitoring means further includes means for monitoring axial shaft vibration; means to vary a machine parameter operatively coupled to the machine, and processing means interposed between said monitoring means and said means to vary said machine parameter to enable said means to vary said machine parameter upon indication of a prestall condition.
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Specification