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A Double Transducer for High Precision Ultrasonic Time-Domain Reflectometry Measurements.

Stade S, Hakkarainen T, Kallioinen M, Mänttäri M, Tuuva T - Sensors (Basel) (2015)

Bottom Line: A double transducer described in this study eliminates the need for a separate reference transducer because in the double transducer the reference measurement is included in the design of the transducer holder.Two sensors in the same holder require less space.Other advantage is that the double transducer can be placed near the measurement target and hence the local sonic velocity can be determined.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Separation Technology, School of Engineering Science, Lappeenranta University of Technology, P.O. Box 20, Lappeenranta FI-53851, Finland. stade@lut.fi.

ABSTRACT
Membrane fouling, where unwanted particles accumulate on the membrane surface and reduce its permeability, causes problems in membrane filtration processes. With ultrasonic time-domain reflectometry (UTDR) it is possible to measure the extent of membrane fouling and hence take actions to minimize it. However, the usability of UTDR is very limited to constant filtration conditions if the sonic velocity, which has a great impact on UTDR measurement accuracy, is unknown. With a reference transducer the actual sonic velocity can be measured. This requires another transducer to be installed in the module, where there may be only limited space or the module dimensions may not be suitable for the reference transducer. A double transducer described in this study eliminates the need for a separate reference transducer because in the double transducer the reference measurement is included in the design of the transducer holder. Two sensors in the same holder require less space. Other advantage is that the double transducer can be placed near the measurement target and hence the local sonic velocity can be determined.

No MeSH data available.


Experimental setup for UTDR. Ultrasonic transducer is attached to an adjustable holder which distance can be changed with a micrometer screw. Ultrasonic pulse is generated with a pulser and monitored with an oscilloscope.
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sensors-15-15090-f005: Experimental setup for UTDR. Ultrasonic transducer is attached to an adjustable holder which distance can be changed with a micrometer screw. Ultrasonic pulse is generated with a pulser and monitored with an oscilloscope.

Mentions: An electric pulse was generated by a pulser which sends 10 MHz electric pulses to both crystals at the same time. The pulser device has five terminals; two outputs for the transmission signals to the crystals, two outputs for the two oscilloscope channels and one output for the synchronization signal. The pulse is triggered in the oscilloscope with an external trigger signal which is timed so that the signal is received from the start where the pulse is generated and the trigger signal ends at the time when the signal is assumed to complete its roundtrip from the sensor to the bottom of the Petri dish and back to the sensor. The time difference between the sent and received pulses (echoes) was detected with an oscilloscope. An example of the sent pulse and received echo in time- and frequency domain are shown in the Figure 3a–d. The fundamental idea of the double transducer is to measure the sonic velocity simultaneously with the distance measurement under variable environmental conditions such as temperature changes. The fixed distance between sensors of the double transducer (Figure 4) can be used to calculate the sonic velocity from the time difference between these two signals. The fixed distance has to be determined for the double transducer. It can be done with a simple “calibration” measurement using a device like the one shown in Figure 5.


A Double Transducer for High Precision Ultrasonic Time-Domain Reflectometry Measurements.

Stade S, Hakkarainen T, Kallioinen M, Mänttäri M, Tuuva T - Sensors (Basel) (2015)

Experimental setup for UTDR. Ultrasonic transducer is attached to an adjustable holder which distance can be changed with a micrometer screw. Ultrasonic pulse is generated with a pulser and monitored with an oscilloscope.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541822&req=5

sensors-15-15090-f005: Experimental setup for UTDR. Ultrasonic transducer is attached to an adjustable holder which distance can be changed with a micrometer screw. Ultrasonic pulse is generated with a pulser and monitored with an oscilloscope.
Mentions: An electric pulse was generated by a pulser which sends 10 MHz electric pulses to both crystals at the same time. The pulser device has five terminals; two outputs for the transmission signals to the crystals, two outputs for the two oscilloscope channels and one output for the synchronization signal. The pulse is triggered in the oscilloscope with an external trigger signal which is timed so that the signal is received from the start where the pulse is generated and the trigger signal ends at the time when the signal is assumed to complete its roundtrip from the sensor to the bottom of the Petri dish and back to the sensor. The time difference between the sent and received pulses (echoes) was detected with an oscilloscope. An example of the sent pulse and received echo in time- and frequency domain are shown in the Figure 3a–d. The fundamental idea of the double transducer is to measure the sonic velocity simultaneously with the distance measurement under variable environmental conditions such as temperature changes. The fixed distance between sensors of the double transducer (Figure 4) can be used to calculate the sonic velocity from the time difference between these two signals. The fixed distance has to be determined for the double transducer. It can be done with a simple “calibration” measurement using a device like the one shown in Figure 5.

Bottom Line: A double transducer described in this study eliminates the need for a separate reference transducer because in the double transducer the reference measurement is included in the design of the transducer holder.Two sensors in the same holder require less space.Other advantage is that the double transducer can be placed near the measurement target and hence the local sonic velocity can be determined.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Separation Technology, School of Engineering Science, Lappeenranta University of Technology, P.O. Box 20, Lappeenranta FI-53851, Finland. stade@lut.fi.

ABSTRACT
Membrane fouling, where unwanted particles accumulate on the membrane surface and reduce its permeability, causes problems in membrane filtration processes. With ultrasonic time-domain reflectometry (UTDR) it is possible to measure the extent of membrane fouling and hence take actions to minimize it. However, the usability of UTDR is very limited to constant filtration conditions if the sonic velocity, which has a great impact on UTDR measurement accuracy, is unknown. With a reference transducer the actual sonic velocity can be measured. This requires another transducer to be installed in the module, where there may be only limited space or the module dimensions may not be suitable for the reference transducer. A double transducer described in this study eliminates the need for a separate reference transducer because in the double transducer the reference measurement is included in the design of the transducer holder. Two sensors in the same holder require less space. Other advantage is that the double transducer can be placed near the measurement target and hence the local sonic velocity can be determined.

No MeSH data available.