Coriolis effect mass flowmeter
First Claim
1. A method of determining information including the mass flow rate of material flowing through a pipe section which is an integral part of an existing pipe system that is devoid of material flow measurement means, said method comprising the steps of:
- affixing a motion sensor to a first location comprising a zero flow node of a harmonic of the natural frequency of vibration of said pipe section;
affixing a vibration driver to a second location of said pipe section;
operating said driver to oscillate said pipe section at said harmonic frequency;
said sensor and said driver being attached only to said pipe section and being free from attachment to a non-movable object; and
determining the mass flow rate of said material flowing through said pipe section by measuring with said motion sensor the amplitude of transverse deflections of said first location of said pipe section in a direction perpendicular to the longitudinal axis of said pipe section;
said transverse deflections of said pipe section being caused jointly by the oscillation of said pipe section and the Coriolis motion of said pipe section due to the flow of material through said pipe section.
1 Assignment
0 Petitions
Accused Products
Abstract
A Coriolis effect mass flowmeter for measuring mass material flow in a conduit. Elements of the meter are clamped directly onto an existing pipe or other conduit without diversion of the flow. The meter comprises a driver, such as a magnetostrictive driver, to oscillate a section of pipe between two supports. The driver is mounted on the pipe section at or near an anti-node of the second harmonic mode of the natural frequency of the pipe section. A sensor, such as an accelerometer, is mounted onto the pipe section at the node point of the second harmonic mode of the natural frequency of the pipe section during zero flow, (zero flow node point). The second sensor measures the amplitude of displacement of the zero flow node point due to the Coriolis effect forces from the mass of the material flowing through the oscillating pipe. This measurement is indicative of the mass flow rate of the material flowing through the pipe. The meter is not dependent upon phase shift detection and is not susceptible to extraneous noise and does not require a complicated mounting. In one alternative embodiment, the meter is prefabricated on a section of pipe which can then be installed in a pipeline as an off the shelf item. In another alternative embodiment, a pair of sensors is affixed to different locations of the pipe section to generate phase or time separated signals. The signals are applied to processing circuitry that determines mass flow rate information from the phase or time separated signals.
129 Citations
28 Claims
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1. A method of determining information including the mass flow rate of material flowing through a pipe section which is an integral part of an existing pipe system that is devoid of material flow measurement means, said method comprising the steps of:
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affixing a motion sensor to a first location comprising a zero flow node of a harmonic of the natural frequency of vibration of said pipe section; affixing a vibration driver to a second location of said pipe section; operating said driver to oscillate said pipe section at said harmonic frequency; said sensor and said driver being attached only to said pipe section and being free from attachment to a non-movable object; and determining the mass flow rate of said material flowing through said pipe section by measuring with said motion sensor the amplitude of transverse deflections of said first location of said pipe section in a direction perpendicular to the longitudinal axis of said pipe section; said transverse deflections of said pipe section being caused jointly by the oscillation of said pipe section and the Coriolis motion of said pipe section due to the flow of material through said pipe section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of determining the mass flow rate of material flowing through a pipe section which is an integral part of an existing pipe system devoid of material flow measurement conduit means, said method comprising the steps of:
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clamping said pipe section at a first and a second location spaced apart from each other to inhibit transverse motion of said pipe section at said first and second locations; affixing a first motion sensor to said pipe section at a third location between said first and second locations, said third location comprising a zero flow vibration node for a harmonic of the natural frequency of vibration of said pipe section; affixing a vibration driver to said pipe at a fourth location between said third location and said first location, said fourth location not comprising a vibration node of said pipe section at said harmonic frequency; said motion sensor and said vibration driver being attached only to said pipe section and being free from attachment to a non-movable object; and operating said driver to oscillate said pipe section at said harmonic frequency; and determining the mass flow rate of said material through said pipe section by measuring with said motion sensor the amplitude of transverse deflections of said third location of said pipe section in a direction perpendicular to the longitudinal axis of said pipe section; said transverse deflections of said third location being caused jointly by the Coriolis motion of pipe section due to said material flow and said oscillation of said pipe section. - View Dependent Claims (11, 12, 13)
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14. A method of determining the mass flow rate of material flowing through a pipe section which is an integral part of an existing pipe system devoid of material flow measurement conduit means, said method comprising the steps of:
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clamping said pipe section at a first and a second location spaced apart from each other to inhibit transverse motion of said pipe section at said first and second locations; affixing motion sensor means to said pipe section between said first and second locations; affixing a vibration driver to said pipe section between said first and second locations; said motion sensor means and said driver being attached only to said pipe section and being free from attachment to a non-movable object; operating said driver to oscillate said pipe section at a harmonic of a natural frequency of vibration of said pipe section; and determining the mass flow rate of said material through said pipe section by measuring with said motion sensor means the transverse deflections of said of said pipe section caused jointly by the oscillation of said pipe section and the Coriolis motion of said pipe section due to the flow of material through said pipe section. - View Dependent Claims (15, 16, 17)
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18. A Coriolis flowmeter for measuring the mass flow rate of material flowing in a pipe section;
- said flowmeter comprising;
support means clamped to first and second spaced apart locations of said pipe section to inhibit transverse motion of said pipe section; motion sensors affixed to different locations of said pipe section intermediate said first and second locations for detecting transverse deflections of said pipe section; driver means affixed to said pipe section intermediate said first and second locations; said motion sensors and said driver means being clamped directly onto said pipe section and being free from attachment to a non-movable object; means for operating said driver means to oscillate said pipe section at a harmonic of the natural frequency of vibration of said pipe section; and said motion sensors being responsive to transverse deflections of said pipe section resulting jointly from the Coriolis motion of said pipe section due to said material flow and said oscillation of said pipe section caused by said driver means to generate output signals indicative of said deflections; means for applying said output signals of said motion sensors to measuring apparatus; and said measuring apparatus being responsive to the said application of said output signals for determining the mass flow rate of said material in said pipe section. - View Dependent Claims (19, 20, 21, 22, 23, 24)
- said flowmeter comprising;
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25. A Coriolis flowmeter for determining the mass flow rate of material flowing through a pipe section, said flowmeter comprising:
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support means attached to first and second spaced apart location of said pipe section to inhibit transverse motion of said pipe section; a first motion sensor affixed to said pipe section at a third location between said first and second locations, said third location comprising a zero flow vibration node for a harmonic of the natural frequency of vibration of said pipe section; a vibration driver affixed to said pipe section at a fourth location between said third location and said first location, said fourth location not being a vibration node of said pipe section at said harmonic frequency; said motion sensor and said driver being attached only to said pipe section and being free from attachment to a non-movable object; means for operating said driver to oscillate said pipe section at said harmonic frequency; and means for determining the mass flow rate of said material through said pipe section by measuring with said motion sensor the amplitude of the transverse deflections of said third location of said pipe section in a direction perpendicular to the longitudinal axis of said pipe section; said transverse deflections of said third pipe section location being caused jointly by the Coriolis motion of said pipe section due to said material flow and said oscillation of said pipe section. - View Dependent Claims (26)
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27. A method of determining information including the mass flow rate of material flowing through a pipe section which is an integral part of an existing pipe system, said method comprising the steps of:
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affixing a motion sensor to a said pipe section; affixing a vibration driver to said pipe section; said motion sensor and said vibration driver being attached only to said pipe section and being devoid of attachment to a non-movable object; said vibration driver comprising a magnetostrictive transducer for oscillating said pipe section; applying a drive current to said magnetostrictive transducer to oscillate said pipe section by forcing a magnetostrictive element in said transducer to elongate and return to normal length according to the frequency of said drive current; adjusting said frequency of said drive current to operate said driver to drive said pipe section at said harmonic frequency; and determining the mass flow rate of said material flowing through said pipe section by measuring with said motion sensor the amplitude of a transverse deflection of said pipe section in a direction perpendicular to the longitudinal axis of said pipe section; said deflections being caused jointly by said oscillations and the Coriolis motion of said pipe section due to said material flow. - View Dependent Claims (28)
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Specification