Methods and Sensors for the Detection of Active Carbon Filters Degradation with EMIS-ECIS PWAS

A system operative to detect active carbon filter degradations, said system comprising:

• a plurality of piezoelectric wafer active sensors embedded into an active carbon filtration device;
• an impedance measurement circuit configured to measure the impedance of each piezoelectric wafer active sensor embedded into the active carbon filtration device;
• and
• a signal processor configured to control the impedance measurement circuit to perform impedance measurement on each piezoelectric wafer active sensor embedded into the active carbon filtration device and to process received electromechanical impedance spectroscopy and electrochemical impedance spectroscopy signals from each piezoelectric wafer active sensor embedded into the active carbon filtration device.

A method of assessing filter degradation status of an activated carbon filter, wherein a plurality of piezoelectric wafer active sensors are positioned on the activated carbon filter, the method comprising:

• measuring impedance spectra of pristine status at selected frequencies based on the selected methodology;
• saving pristine spectra data in said signal processor as baseline data;
• measuring impedance spectra of said piezoelectric wafer active sensors at desired intervals;
• storing the impedance spectra in the signal processor;
• and
• analyzing the measured impedance spectra using selected methodology and compare with the said baseline data to estimate the degradation status of said filter.