The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Tetsuya Wakui - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
ASME 2008 Power Conference, 2008Co-Authors: Jyun-ichi Eino, Nobuo Miyaji, Akira Uehara, Tetsuya Wakui, Takumi Hasizume, Yoshitaka YuukiAbstract:The combination use of a differential pressure transmitter, orifice and Impulse Line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is Impulse Line blockage, an onLine blockage detection system is required. In previous works, the authors developed an indicator of Impulse Line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of Line pressure change increase. In addition, there are continuous and frequent Line pressure changes in certain applications. Hence, the objective of this study is to detect Impulse Line blockages even when the Line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid Line pressure changes under which the former blockage index failed.Copyright © 2008 by ASME
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Diagnostics of Impulse Line blockage with multi-sensing differential pressure transmitter in oil Line
2008 SICE Annual Conference, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:A differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter at the operation site is the blockage of the Impulse Line, which connects an orifice tap with a differential pressure transmitter. In this study, we investigate the relation between the amplitude of the pressure fluctuation in the oil Line and the kinetic viscosity (1.0 times 10-5 to 3.0 times 10-5 m2/s). By conducting experiments in a water Line, we have developed a method to diagnose the blockage of the Impulse Line. Hence, we use this method to diagnose the blockage in a Line that carries a highly viscous fluid. Through experimental investigations, the following results are clarified: 1) The highly viscous fluid in the Impulse Line does not reduce the pressure fluctuation occurring at the multi-sensing differential pressure transmitter. 2) Highly viscous flow in the main Line has small pressure fluctuations; however, these fluctuations have the same characteristics of the Impulse Line blockage as those in a water Line. Therefore, the proposed method can diagnose the Impulse Line blockage in an oil Line as well as in a water Line.
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Diagnostics of Impulse Line Blockage with Multi-Sensing Differential Pressure Transmitter at Oil Line
Journal of System Design and Dynamics, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:Differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter used at operation sites is the blockage of an Impulse Line, which connects a differential pressure transmitter with an orifice tap. In our previous studies, experiments at a water Line showed that the diagnostic method based on the pressure fluctuations in the Impulse Line can diagnose the blockage in the steady state. In this method, however, there was a possibility of making a wrong diagnosis in the transient state. This paper clarifies the applicable conditions of two diagnostic methods: the diagnostic method based on the pressure fluctuations and the diagnostic method based on the phase difference. In particular, the effectiveness of two diagnostic methods in both steady and transient states is investigated by comparing the experimental results at an air Line with those obtained at the water Line. Through experimental investigations, the following results are derived: (1) The Line pressure change has a harmful effect on the blockage diagnosis with the pressure fluctuations. (2) The diagnostic method based on the phase difference can diagnose the blockage even in the transient state; however, this method cannot diagnose the blockage, where the pressure fluctuations are not transmitted at an air Line. Therefore, the method based on phase differences remains to be improved in the future work.
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Impulse Line Blocking Diagnosis of Digital differential pressure transmitter
2006 SICE-ICASE International Joint Conference, 2006Co-Authors: Yoshitaka Yuki, Kenichi Kuromori, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya WakuiAbstract:Differential pressure transmitter with an orifice has achieved great field performance and success in flow measurement as a reliable field flow meter. However, blockage in Impulse Line attached to transmitter is sometime caused by precipitating or solidifying liquids. The pressure signals have random fluctuation signals due to a turbulent flow in a pipeLine, and in case of Impulse Line blockage, the fluctuation signals vary from that of normal conditions. Mean square of differential pressure fluctuation has formerly been used to evaluate the blocking state. However, mean square of differential pressure fluctuation is strongly affected by flow rate. Then we have developed a new diagnostic technique, in which a specific parameter F called 'blockage factor' indicates the extent of each Impulse Line blockage. Dp transmitter EJX series is able to measure not only the differential pressure but also the static pressure at high and low pressure sides of orifice by means of silicon resonant pressure sensor. EJX makes it possible to calculate statistical variables F by using three pressure signals. We confirmed that blockage can be detected by using statistical variables F. Thus, Impulse Line blocking diagnosis of digital differential pressure transmitter contributes to predicting blockage in Impulse Line and saving maintenance cost
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Impulse LineBlocking Diagnosis ofDigital differential pressure transmitter
2006Co-Authors: Kenichi Kuromori, Tetsuya WakuiAbstract:Differential pressure transmitter withanorifice hasachieved great field performance andsuccess inflowmeasurement asareliable field flowmeter. However, blockage inImpulse Lineattached totransmitter issometime caused by precipitating orsolidifying liquids. Thepressure signals haverandomfluctuation signals duetoaturbulent flowina pipeLine, andincaseofImpulse Line blockage, thefluctuation signals varyfromthat ofnormal conditions. Meansquare ofdifferential pressure fluctuation hasformerly beenusedtoevaluate theblocking state. However, meansquare of differential pressure fluctuation isstrongly affected byflowrate. Thenwehavedeveloped anewdiagnostic technique, in whichaspecific parameter Fcalled 'Blockage factor' indicates theextent ofeachImpulse Line blockage. Dptransmitter EJXseries isable tomeasure notonly thedifferential pressure butalso thestatic pressure athighandlowpressure sides oforifice bymeansofSilicon resonant pressure sensor. EJXmakesitpossible tocalculate statistical variables Fbyusing three pressure signals. We confirmed that blockage canbedetected byusing statistical variables F.Thus, Impulse Line blocking diagnosis ofdigital differential pressure transmitter contributes topredicting blockage inImpulse Line and saving maintenance cost.
Yoshitaka Yuuki - One of the best experts on this subject based on the ideXlab platform.
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Diagnostics of Impulse Line blockage with multi-sensing differential pressure transmitter in oil Line
2008 SICE Annual Conference, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:A differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter at the operation site is the blockage of the Impulse Line, which connects an orifice tap with a differential pressure transmitter. In this study, we investigate the relation between the amplitude of the pressure fluctuation in the oil Line and the kinetic viscosity (1.0 times 10-5 to 3.0 times 10-5 m2/s). By conducting experiments in a water Line, we have developed a method to diagnose the blockage of the Impulse Line. Hence, we use this method to diagnose the blockage in a Line that carries a highly viscous fluid. Through experimental investigations, the following results are clarified: 1) The highly viscous fluid in the Impulse Line does not reduce the pressure fluctuation occurring at the multi-sensing differential pressure transmitter. 2) Highly viscous flow in the main Line has small pressure fluctuations; however, these fluctuations have the same characteristics of the Impulse Line blockage as those in a water Line. Therefore, the proposed method can diagnose the Impulse Line blockage in an oil Line as well as in a water Line.
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Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
ASME 2008 Power Conference, 2008Co-Authors: Jyun-ichi Eino, Nobuo Miyaji, Akira Uehara, Tetsuya Wakui, Takumi Hasizume, Yoshitaka YuukiAbstract:The combination use of a differential pressure transmitter, orifice and Impulse Line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is Impulse Line blockage, an onLine blockage detection system is required. In previous works, the authors developed an indicator of Impulse Line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of Line pressure change increase. In addition, there are continuous and frequent Line pressure changes in certain applications. Hence, the objective of this study is to detect Impulse Line blockages even when the Line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid Line pressure changes under which the former blockage index failed.Copyright © 2008 by ASME
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Diagnostics of Impulse Line Blockage with Multi-Sensing Differential Pressure Transmitter at Oil Line
Journal of System Design and Dynamics, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:Differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter used at operation sites is the blockage of an Impulse Line, which connects a differential pressure transmitter with an orifice tap. In our previous studies, experiments at a water Line showed that the diagnostic method based on the pressure fluctuations in the Impulse Line can diagnose the blockage in the steady state. In this method, however, there was a possibility of making a wrong diagnosis in the transient state. This paper clarifies the applicable conditions of two diagnostic methods: the diagnostic method based on the pressure fluctuations and the diagnostic method based on the phase difference. In particular, the effectiveness of two diagnostic methods in both steady and transient states is investigated by comparing the experimental results at an air Line with those obtained at the water Line. Through experimental investigations, the following results are derived: (1) The Line pressure change has a harmful effect on the blockage diagnosis with the pressure fluctuations. (2) The diagnostic method based on the phase difference can diagnose the blockage even in the transient state; however, this method cannot diagnose the blockage, where the pressure fluctuations are not transmitted at an air Line. Therefore, the method based on phase differences remains to be improved in the future work.
Jyun-ichi Eino - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
ASME 2008 Power Conference, 2008Co-Authors: Jyun-ichi Eino, Nobuo Miyaji, Akira Uehara, Tetsuya Wakui, Takumi Hasizume, Yoshitaka YuukiAbstract:The combination use of a differential pressure transmitter, orifice and Impulse Line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is Impulse Line blockage, an onLine blockage detection system is required. In previous works, the authors developed an indicator of Impulse Line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of Line pressure change increase. In addition, there are continuous and frequent Line pressure changes in certain applications. Hence, the objective of this study is to detect Impulse Line blockages even when the Line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid Line pressure changes under which the former blockage index failed.Copyright © 2008 by ASME
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Diagnostics of Impulse Line blockage with multi-sensing differential pressure transmitter in oil Line
2008 SICE Annual Conference, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:A differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter at the operation site is the blockage of the Impulse Line, which connects an orifice tap with a differential pressure transmitter. In this study, we investigate the relation between the amplitude of the pressure fluctuation in the oil Line and the kinetic viscosity (1.0 times 10-5 to 3.0 times 10-5 m2/s). By conducting experiments in a water Line, we have developed a method to diagnose the blockage of the Impulse Line. Hence, we use this method to diagnose the blockage in a Line that carries a highly viscous fluid. Through experimental investigations, the following results are clarified: 1) The highly viscous fluid in the Impulse Line does not reduce the pressure fluctuation occurring at the multi-sensing differential pressure transmitter. 2) Highly viscous flow in the main Line has small pressure fluctuations; however, these fluctuations have the same characteristics of the Impulse Line blockage as those in a water Line. Therefore, the proposed method can diagnose the Impulse Line blockage in an oil Line as well as in a water Line.
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Diagnostics of Impulse Line Blockage with Multi-Sensing Differential Pressure Transmitter at Oil Line
Journal of System Design and Dynamics, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:Differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter used at operation sites is the blockage of an Impulse Line, which connects a differential pressure transmitter with an orifice tap. In our previous studies, experiments at a water Line showed that the diagnostic method based on the pressure fluctuations in the Impulse Line can diagnose the blockage in the steady state. In this method, however, there was a possibility of making a wrong diagnosis in the transient state. This paper clarifies the applicable conditions of two diagnostic methods: the diagnostic method based on the pressure fluctuations and the diagnostic method based on the phase difference. In particular, the effectiveness of two diagnostic methods in both steady and transient states is investigated by comparing the experimental results at an air Line with those obtained at the water Line. Through experimental investigations, the following results are derived: (1) The Line pressure change has a harmful effect on the blockage diagnosis with the pressure fluctuations. (2) The diagnostic method based on the phase difference can diagnose the blockage even in the transient state; however, this method cannot diagnose the blockage, where the pressure fluctuations are not transmitted at an air Line. Therefore, the method based on phase differences remains to be improved in the future work.
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Impulse Line Blocking Diagnosis of Digital differential pressure transmitter
2006 SICE-ICASE International Joint Conference, 2006Co-Authors: Yoshitaka Yuki, Kenichi Kuromori, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya WakuiAbstract:Differential pressure transmitter with an orifice has achieved great field performance and success in flow measurement as a reliable field flow meter. However, blockage in Impulse Line attached to transmitter is sometime caused by precipitating or solidifying liquids. The pressure signals have random fluctuation signals due to a turbulent flow in a pipeLine, and in case of Impulse Line blockage, the fluctuation signals vary from that of normal conditions. Mean square of differential pressure fluctuation has formerly been used to evaluate the blocking state. However, mean square of differential pressure fluctuation is strongly affected by flow rate. Then we have developed a new diagnostic technique, in which a specific parameter F called 'blockage factor' indicates the extent of each Impulse Line blockage. Dp transmitter EJX series is able to measure not only the differential pressure but also the static pressure at high and low pressure sides of orifice by means of silicon resonant pressure sensor. EJX makes it possible to calculate statistical variables F by using three pressure signals. We confirmed that blockage can be detected by using statistical variables F. Thus, Impulse Line blocking diagnosis of digital differential pressure transmitter contributes to predicting blockage in Impulse Line and saving maintenance cost
Nobuo Miyaji - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
ASME 2008 Power Conference, 2008Co-Authors: Jyun-ichi Eino, Nobuo Miyaji, Akira Uehara, Tetsuya Wakui, Takumi Hasizume, Yoshitaka YuukiAbstract:The combination use of a differential pressure transmitter, orifice and Impulse Line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is Impulse Line blockage, an onLine blockage detection system is required. In previous works, the authors developed an indicator of Impulse Line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of Line pressure change increase. In addition, there are continuous and frequent Line pressure changes in certain applications. Hence, the objective of this study is to detect Impulse Line blockages even when the Line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid Line pressure changes under which the former blockage index failed.Copyright © 2008 by ASME
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Diagnostics of Impulse Line blockage with multi-sensing differential pressure transmitter in oil Line
2008 SICE Annual Conference, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:A differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter at the operation site is the blockage of the Impulse Line, which connects an orifice tap with a differential pressure transmitter. In this study, we investigate the relation between the amplitude of the pressure fluctuation in the oil Line and the kinetic viscosity (1.0 times 10-5 to 3.0 times 10-5 m2/s). By conducting experiments in a water Line, we have developed a method to diagnose the blockage of the Impulse Line. Hence, we use this method to diagnose the blockage in a Line that carries a highly viscous fluid. Through experimental investigations, the following results are clarified: 1) The highly viscous fluid in the Impulse Line does not reduce the pressure fluctuation occurring at the multi-sensing differential pressure transmitter. 2) Highly viscous flow in the main Line has small pressure fluctuations; however, these fluctuations have the same characteristics of the Impulse Line blockage as those in a water Line. Therefore, the proposed method can diagnose the Impulse Line blockage in an oil Line as well as in a water Line.
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Diagnostics of Impulse Line Blockage with Multi-Sensing Differential Pressure Transmitter at Oil Line
Journal of System Design and Dynamics, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:Differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter used at operation sites is the blockage of an Impulse Line, which connects a differential pressure transmitter with an orifice tap. In our previous studies, experiments at a water Line showed that the diagnostic method based on the pressure fluctuations in the Impulse Line can diagnose the blockage in the steady state. In this method, however, there was a possibility of making a wrong diagnosis in the transient state. This paper clarifies the applicable conditions of two diagnostic methods: the diagnostic method based on the pressure fluctuations and the diagnostic method based on the phase difference. In particular, the effectiveness of two diagnostic methods in both steady and transient states is investigated by comparing the experimental results at an air Line with those obtained at the water Line. Through experimental investigations, the following results are derived: (1) The Line pressure change has a harmful effect on the blockage diagnosis with the pressure fluctuations. (2) The diagnostic method based on the phase difference can diagnose the blockage even in the transient state; however, this method cannot diagnose the blockage, where the pressure fluctuations are not transmitted at an air Line. Therefore, the method based on phase differences remains to be improved in the future work.
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Impulse Line Blocking Diagnosis of Digital differential pressure transmitter
2006 SICE-ICASE International Joint Conference, 2006Co-Authors: Yoshitaka Yuki, Kenichi Kuromori, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya WakuiAbstract:Differential pressure transmitter with an orifice has achieved great field performance and success in flow measurement as a reliable field flow meter. However, blockage in Impulse Line attached to transmitter is sometime caused by precipitating or solidifying liquids. The pressure signals have random fluctuation signals due to a turbulent flow in a pipeLine, and in case of Impulse Line blockage, the fluctuation signals vary from that of normal conditions. Mean square of differential pressure fluctuation has formerly been used to evaluate the blocking state. However, mean square of differential pressure fluctuation is strongly affected by flow rate. Then we have developed a new diagnostic technique, in which a specific parameter F called 'blockage factor' indicates the extent of each Impulse Line blockage. Dp transmitter EJX series is able to measure not only the differential pressure but also the static pressure at high and low pressure sides of orifice by means of silicon resonant pressure sensor. EJX makes it possible to calculate statistical variables F by using three pressure signals. We confirmed that blockage can be detected by using statistical variables F. Thus, Impulse Line blocking diagnosis of digital differential pressure transmitter contributes to predicting blockage in Impulse Line and saving maintenance cost
Akira Uehara - One of the best experts on this subject based on the ideXlab platform.
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Diagnostics of Impulse Line blockage with multi-sensing differential pressure transmitter in oil Line
2008 SICE Annual Conference, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:A differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter at the operation site is the blockage of the Impulse Line, which connects an orifice tap with a differential pressure transmitter. In this study, we investigate the relation between the amplitude of the pressure fluctuation in the oil Line and the kinetic viscosity (1.0 times 10-5 to 3.0 times 10-5 m2/s). By conducting experiments in a water Line, we have developed a method to diagnose the blockage of the Impulse Line. Hence, we use this method to diagnose the blockage in a Line that carries a highly viscous fluid. Through experimental investigations, the following results are clarified: 1) The highly viscous fluid in the Impulse Line does not reduce the pressure fluctuation occurring at the multi-sensing differential pressure transmitter. 2) Highly viscous flow in the main Line has small pressure fluctuations; however, these fluctuations have the same characteristics of the Impulse Line blockage as those in a water Line. Therefore, the proposed method can diagnose the Impulse Line blockage in an oil Line as well as in a water Line.
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Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
ASME 2008 Power Conference, 2008Co-Authors: Jyun-ichi Eino, Nobuo Miyaji, Akira Uehara, Tetsuya Wakui, Takumi Hasizume, Yoshitaka YuukiAbstract:The combination use of a differential pressure transmitter, orifice and Impulse Line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is Impulse Line blockage, an onLine blockage detection system is required. In previous works, the authors developed an indicator of Impulse Line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of Line pressure change increase. In addition, there are continuous and frequent Line pressure changes in certain applications. Hence, the objective of this study is to detect Impulse Line blockages even when the Line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid Line pressure changes under which the former blockage index failed.Copyright © 2008 by ASME
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Diagnostics of Impulse Line Blockage with Multi-Sensing Differential Pressure Transmitter at Oil Line
Journal of System Design and Dynamics, 2008Co-Authors: Akira Uehara, Nobuo Miyaji, Jyun-ichi Eino, Takumi Hashizume, Tetsuya Wakui, Yoshitaka YuukiAbstract:Differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter used at operation sites is the blockage of an Impulse Line, which connects a differential pressure transmitter with an orifice tap. In our previous studies, experiments at a water Line showed that the diagnostic method based on the pressure fluctuations in the Impulse Line can diagnose the blockage in the steady state. In this method, however, there was a possibility of making a wrong diagnosis in the transient state. This paper clarifies the applicable conditions of two diagnostic methods: the diagnostic method based on the pressure fluctuations and the diagnostic method based on the phase difference. In particular, the effectiveness of two diagnostic methods in both steady and transient states is investigated by comparing the experimental results at an air Line with those obtained at the water Line. Through experimental investigations, the following results are derived: (1) The Line pressure change has a harmful effect on the blockage diagnosis with the pressure fluctuations. (2) The diagnostic method based on the phase difference can diagnose the blockage even in the transient state; however, this method cannot diagnose the blockage, where the pressure fluctuations are not transmitted at an air Line. Therefore, the method based on phase differences remains to be improved in the future work.
