Method and apparatus for real-time, on-line monitoring of wear in machinery
First Claim
1. A method of monitoring the rate of wear of a machine having ferromagnetic components which wear during operation resulting in the production of ferromagnetic particulate material, said machine having a lubrication system utilizing a lubricating fluid, in which said material becomes entrained, for lubricating said components, said method comprising the steps of:
- passing a sample stream of said lubricating fluid at a uniform rate of flow axially through an inductance coil of an RF oscillator operating at a base frequenty arranged such that the frequency of the output signal of said oscillator deviates from said base frequency in proportion to the mass of the ferromagnetic material in the fluid passing through the coil;
periodically accumulating ferromagnetic particulate material at a site in said sample stream upstream of said coil for a predetermined time interval;
releasing material accumulated thereat at the conclusion of said interval; and
integrating with respect to time the frequency transient in the oscillator output signal resulting from said the passage of said accumulated material through said inductance coil to provide a signal proportional to the concentration of ferromagnetic particulate material in said lubricating fluid; and
comparing said proportional signal with a predetermined threshold to provide an indication of the rate of wear of said machine.
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Abstract
The specification describes a method and an apparatus for detecting and quantitatively assessing wear of a machine having ferromagnetic components subjected to wear during operation resulting in the production of ferromagnetic particulate wear debris, and a lubrication system utilizing a lubricating fluid, in which the wear debris becomes entrained, for lubricating the components. The method comprises the steps of passing a sample stream of the lubricating fluid at a predetermined rate of flow axially through the core of an inductance coil of a sample oscillator for producing a time varying signal which deviates from a predetermined value in proportion to the mass of ferromagnetic material contained in the fluid passing through the core, monitoring the rate of change of signal and activating an indicator when the rate of change of the signal exceeds a predetermined level.
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Citations
23 Claims
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1. A method of monitoring the rate of wear of a machine having ferromagnetic components which wear during operation resulting in the production of ferromagnetic particulate material, said machine having a lubrication system utilizing a lubricating fluid, in which said material becomes entrained, for lubricating said components, said method comprising the steps of:
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passing a sample stream of said lubricating fluid at a uniform rate of flow axially through an inductance coil of an RF oscillator operating at a base frequenty arranged such that the frequency of the output signal of said oscillator deviates from said base frequency in proportion to the mass of the ferromagnetic material in the fluid passing through the coil; periodically accumulating ferromagnetic particulate material at a site in said sample stream upstream of said coil for a predetermined time interval; releasing material accumulated thereat at the conclusion of said interval; and integrating with respect to time the frequency transient in the oscillator output signal resulting from said the passage of said accumulated material through said inductance coil to provide a signal proportional to the concentration of ferromagnetic particulate material in said lubricating fluid; and comparing said proportional signal with a predetermined threshold to provide an indication of the rate of wear of said machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A real-time, on-line apparatus for monitoring the rate of wear of a machine having ferromagnetic components which wear during operation resulting in the production of ferromagnetic particulate material, said machine having a lubrication system utilizing a lubricating fluid, in which said material becomes entrained, for lubricating said ferromagnetic components, said apparatus comprising:
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means defining a fluid flow passage having one end adapted to be connected to said machine for taking a sample of said lubricating fluid from said machine and another end adapted to be connected to said machine for returning said sample to said machine, said passage having a portion thereof formed of nonmagnetic material; sensing means including an RF oscillator having an inductance coil disposed about said portion of said passage means, said oscillator being adapted to operate at a base RF frequency and produce an RF output signal, said coil being arranged such that the frequency of said RF output signal deviates from said base RF frequency in proportion to the mass of ferromagnetic particulate material entrained in the fluid passing through said coil; means for accumulating ferromagnetic material in said sample stream upstream of said inductance coil; and electrical circuit means for; (a) integrating with respect to time the frequency transient in said RF output signal resulting from the passage of said accumulated material through said coil to provide an integrated output signal; (b) comparing said integrated output signal against a predetermined threshold and providing a second output signal representative of the rate of wear of said machine; and (c) controlling said accumulating means so as to activate said accumulating means for predetermined timed intervals at predetermined increments of time whereby to accumulate ferromagnetic particulate material at said site and deactivate said accumulating means at the end of said intervals whereby to release any accumulation at said site into said fluid passage. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A method of monitoring the wear of a machine having ferromagnetic components subjected to wear during operation resulting in the production of ferromagnetic particulate material, said machine having a lubrication system utilizing a lubricating fluid, in which said material becomes entrained, for lubricating said components, said method comprising the steps of:
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passing a sample stream of said lubricating fluid at a predetermined rate of flow axially through an inductance coil of an RF oscillator operating at a base frequency arranged such that the frequency of the output signal of said oscillator deviates from said base frequency in proportion to the mass of the ferromagnetic material in the fluid passing through said core; periodically accumulating ferromagnetic particulate material at a site in said sample stream upstream of said coil for a predetermined time interval; releasing material accumulated thereat at the conclusion of said interval; detecting the change of the frequency of said output signal from said base frequency; monitoring the rate of flow of said lubricating fluid through said core and adjusting said flow rate so as to maintain it within predetermined limits, said monitoring step including the steps of accumulating ferromagnetic particulate material in said stream at two separate sites upstream of said core for equal predetermined intervals of time, releasing accumulated material at said sites into said stream in predetermined timed sequence, detecting the time interval between the arrival of said accumulations at said core and converting said detected time into a flow rate.
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23. An apparatus for monitoring the rate of wear of a machine having ferromagnetic components subjected to wear during operation resulting in the production of ferromagnetic particulate material, said machine having a lubrication system utilizing a lubrication fluid, in which said material becomes entrained, for lubricating said ferromagnetic components, said apparatus comprising:
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means defining a fluid flow passage having one end adapted to be connected to said device for taking a sample of said lubrication fluid from said device and another end adapted to be connected to said device for returning said sample to said device, said passage having a portion thereof formed of nonmagnetic material; an RF oscillator having an induction coil disposed about said portion of said passage means, said oscillator being adapted to operate at a base RF frequency and product an RF output signal, said coil being arranged such that the frequency of said RF output signal deviates from said base RF frequency in proportion to the mass of ferromagnetic particulate material entrained in the fluid passing through said core; means for accumulating ferromagnetic material in said sample stream upstream of said inductance coil; electrical circuit means for monitoring the change of the frequency of said signal and producing an output signal when the change of the frequency of said signal exceeds a predetermined value and controlling said accumulating means whereby to activate said accumulating means for predetermined timed intervals at predetermined increments of time whereby to accumulate particulate at said site and to deactivate said accumulating means at the end of said intervals whereby to release any accumulation at said site into said fluid passage; and means responsive to said circuit means output signal for providing an indication of a wear condition; means for monitoring the rate of flow of fluid through said passage and providing an indication of a change in said rate of flow, said means for monitoring the rate of flow of fluid through said passage including; first means for accumulating ferromagnetic particulate material in said passage upstream of said coil; second means for accumulating ferromagnetic particulate material in said passage upstream of said coil; control means for activating and deactivating said first and second accumulating means; means responsive to the output of said oscillator for detecting the peak position with respect to time thereof produced in response to accumulated material released by said accumulating means and flowing through said core; timer means responsive to said peak positions for determining the time interval between the peak positions and producing a signal representative of said interval; and means responsive to said interval representative signal for producing a signal representative of the flow rate of said fluid in said passage.
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Specification