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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.


Photographs of the double transducer.
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sensors-15-15090-f002: Photographs of the double transducer.

Mentions: An ultrasonic transducer has a sensor which is a piezoelectric crystal. It can send ultrasonic waves and detect them electrically. The double transducer is a device where two crystals are together (Figure 2). Crystals are made out of lead zirconate titanate (Ferroperm, Humlebaek, Denmark) and they are designed for underwater applications [17]. The commercial name of these crystals is Pz26 (Navy I). The advantages with these crystals are their small size, approximately 10 MHz resonance frequency and relatively high coupling factor compared with other crystals in this class. Resistors, crystals and the tip of holder are covered with an epoxy to keep the acoustic impedance applicable between water and crystals and to protect the electronics from the solution.


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

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

Photographs of the double transducer.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-15090-f002: Photographs of the double transducer.
Mentions: An ultrasonic transducer has a sensor which is a piezoelectric crystal. It can send ultrasonic waves and detect them electrically. The double transducer is a device where two crystals are together (Figure 2). Crystals are made out of lead zirconate titanate (Ferroperm, Humlebaek, Denmark) and they are designed for underwater applications [17]. The commercial name of these crystals is Pz26 (Navy I). The advantages with these crystals are their small size, approximately 10 MHz resonance frequency and relatively high coupling factor compared with other crystals in this class. Resistors, crystals and the tip of holder are covered with an epoxy to keep the acoustic impedance applicable between water and crystals and to protect the electronics from the solution.

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.