Detecting seal leaks in installed valves
First Claim
1. An apparatus for use with a fluid transport system, the system having an upstream pipe, a downstream pipe and a valve connected between the upstream pipe and the downstream pipe for controlling fluid flow through the system, the valve having at east one upstream seal, at least one downstream seal and an inner cavity effectively isolated by the seats from the fluid flow stream the apparatus for detecting the presence of a leak in at least one of the seals and for determining the magnitude of a detected leak, tile apparatus comprising:
- a mechanism for generating random pressure pulses which appear in the inner cavity;
a first sensor for detecting the onset of each pressure pulse which exceeds a predetermined magnitude and for generating a trigger signal for each such detected pressure pulse;
a second sensor in fluid communication with the inner cavity for sensing pressure pulses within the inner cavity and for generating a representative second signal as a function of time for each such sensed pressure pulse;
a third sensor in fluid communication with the fluid flow stream, the third sensor being located at one of (1) a predetermined distance upstream of the upstream seal and (2) a predetermined distance downstream of the downstream seal, the third sensor for sensing pressure pulses and for generating a representative third signal as a function of time for each such sensed pressure pulse;
analysis circuitry for receiving the trigger signals and the second and third sigeals, for sampling the second and third signals at predetermined times following the receipt of a trigger signal, for synchronously averaging each of the sampled signals over multiple records to produce synchronously averaged waveforms, and for using the two resulting synchronous averaged waveforms to determine the existence and the magnitude of a seal leak in at least one of the seals.
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Abstract
An apparatus is disclosed for detecting a leak in a valve and the magnitude of the leak. The valve has an upstream seal, a downstream seal and an inner cavity isolated by the seals. The apparatus comprises a mechanism for generating random pressure pulses in the inner cavity, a first sensor for detecting the onset of each pressure pulse and generating a trigger signal, a second sensor for sensing pressure pulses within the inner cavity and generating a representative second signal for each sensed pressure pulse and a third sensor located either upstream of the upstream seal or downstream of the downstream seal. The third sensor senses pressure pulses and generates a representative third signal for each sensed pressure pulse. Analysis circuitry samples and synchronously averages the second and third signals to determine the existence and magnitude of a seal leak.
33 Citations
20 Claims
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1. An apparatus for use with a fluid transport system, the system having an upstream pipe, a downstream pipe and a valve connected between the upstream pipe and the downstream pipe for controlling fluid flow through the system, the valve having at east one upstream seal, at least one downstream seal and an inner cavity effectively isolated by the seats from the fluid flow stream the apparatus for detecting the presence of a leak in at least one of the seals and for determining the magnitude of a detected leak, tile apparatus comprising:
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a mechanism for generating random pressure pulses which appear in the inner cavity;
a first sensor for detecting the onset of each pressure pulse which exceeds a predetermined magnitude and for generating a trigger signal for each such detected pressure pulse;
a second sensor in fluid communication with the inner cavity for sensing pressure pulses within the inner cavity and for generating a representative second signal as a function of time for each such sensed pressure pulse;
a third sensor in fluid communication with the fluid flow stream, the third sensor being located at one of (1) a predetermined distance upstream of the upstream seal and (2) a predetermined distance downstream of the downstream seal, the third sensor for sensing pressure pulses and for generating a representative third signal as a function of time for each such sensed pressure pulse;
analysis circuitry for receiving the trigger signals and the second and third sigeals, for sampling the second and third signals at predetermined times following the receipt of a trigger signal, for synchronously averaging each of the sampled signals over multiple records to produce synchronously averaged waveforms, and for using the two resulting synchronous averaged waveforms to determine the existence and the magnitude of a seal leak in at least one of the seals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
a housing including an enclosed inner chamber which is in fluid communication with the inner cavity of the valve;
a diaphragm edge mounted within the inner chamber;
an anvil located outside of the housing, the anvil being mechanically coupled to the diaphragm so that movement of the anvil causes the diaphragm to move; and
a ram moveably supported proximate to the anvil, the ram including a wind catcher, whereby wind action causes the ram to move and strike the anvil which in turn causes the diaphragm to move to create a pressure pulse within the chamber, the pressure pulse being transmitted by the fluid to the inner cavity of the valve.
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10. The apparatus as recited in claim 9 wherein the diaphragm is comprised of a thin, generally circular plate of high strength material having a plurality of openings extending therethrough.
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11. The apparatus as recited in claim 9 wherein the anvil is mechanically coupled to the axial center of the diaphragm.
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12. The apparatus as recited in claim 9 wherein the wind catcher comprises a dish having a predetermined diameter.
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13. An apparatus for use with a fluid transport system, the system having an upstream pipe, a downstream pipe and a valve connected between the upstream pipe and the downstream pipe for controlling fluid flow through the system, the valve at least one upstream seal, at least one downstream seal and an inner cavity effectively isolated by the seals from the fluid flow stream, the apparatus for detecting the presence of a leak in at least one of the seals and for determining the magnitude of a detected leak, the apparatus comprising:
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a mechanism for generating random pressure pulse which appears in the inner cavity;
a first sensor for detecting the onset of each pressure pulse which exceeds a predetermined magnitude and for generating a trigger signal for each such detected pressure pulse;
a second sensor in fluid communication with the inner cavity for sensing pressure pulses within the inner cavity and for generating a representative second signal as a function of time for each such sensed pressure pulse;
a third sensor in fluid communication with the fluid flow stream, the third sensor being located at a predetermined distance upstream of the upstream seal for sensing pressure pulses and for generating a representative third signal as a function of time for each such sensed pressure pulse;
a fourth sensor in fluid communication with the fluid flow stream, the fourth sensor being located at a predetermined distance downstream of the downstream seal for sensing pressure pulses and for generating a representative fourth signal as a function of time for each such sensed pressure pulse;
analysis circuitry for receiving the trigger signals and the second, third and fourth signals, for sampling the second, third and fourth signals at predetermined times following the receipt of a trigger signal, for synchronously averaging each of the sampled signals over multiple records to produce synchronously averaged waveforms and for using the synchronously averaged waveforms to determine the existence and the magnitude of a seal leak in either of the seals. - View Dependent Claims (14, 15, 16, 17)
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18. A method for determining the presence and the magnitude of a leak within a fluid transport system, the fluid transport system having an upstream pipe, a downstream pipe and a valve connected between the upstream pipe and the downstream pipe for controlling fluid flow through the system, the valve having at least one upstream seal, at least one downstream seal and at least an inner cavity effectively isolated by the seals from the fluid flow stream, the method comprising:
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generating random pressure pulses which appears in the inner cavity;
generating a trigger signal at the onset of each pressure pulse which exceeds a predetermined magnitude;
sensing each pressure pulse within the inner cavity and generating a representative second signal as function of time for each such sensed pressure pulse;
sensing each pressure pulse within the fluid flow stream at a predetermined distance from the valve and generating a representative third signal as a function of time for each such sensed pressure pulse;
sampling the second and third signals at predetermined times following a trigger signal; and
synchronously averaging each of the sampled signals over multiple records and using the resulting synchronous averaged waveforms to determine the existence and magnitude of a seal leak in at least one of the seals. - View Dependent Claims (19, 20)
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Specification