A nondestructive integrity test for membrane filters based on air-coupled ultrasonic spectroscopy.
This work describes the application of an ultrasonic air-coupled characterization technique to membrane filters. Coefficient of transmission of sound at normal incidence through each membrane in the frequency range 0.55 MHz-2.4 MHz was measured. For all cases, at least one thickness resonance was observed. From these measurements density, velocity, and attenuation of ultrasonic longitudinal waves are calculated and compared to available filtration data such as water flux measurements and bubble point data, both provided by manufacturers. Results show that velocity of ultrasonic waves in membrane filters depends on the membrane grade and can be correlated to filtration properties; attenuation per wavelength is independent of membrane grade but sensitive to moisture content. Advantages of this technique over other conventional membrane tests are pointed out.
Gómez Alvarez-Arenas
Tomás E
TE
Departamento de Señales, Sistemas y Tecnologías Ultrasónicas, Instituto de Acústica, C.S.I.C., 28002 Madrid, Spain. tgomez@ia.cetef.csic.es
D019544:Equipment Failure Analysis / Q000379:methods*; D005240:Feasibility Studies; D005374:Filtration / Q000295:instrumentation* / Q000379:methods*; D008422:Materials Testing / Q000379:methods*; D008567:Membranes, Artificial; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*; D013242:Sterilization / Q000295:instrumentation / Q000379:methods
D008567:Membranes, Artificial