MONITOR OF FLUID MEDIUM

摘要

PURPOSE: To obtain a fluid medium monitor in which damping of wave is suppressed in the fluid medium. CONSTITUTION: The fluid medium monitor comprising a piezoelectric element provided together with a layer having an adsorbing material or a catalytic material is provided with means for generating a surface skimming bulk wave propagating along the piezoelectric element. The layer can limit the wave to the element and can vary the acoustic characteristics in response to the adsorption/holding through chemical coupling with one or more anode liquid of a fluid medium or in response to the chemical and/or physical variation thereof. The fluid medium monitor further comprising a means for monitoring variation in the propagating acoustic wave caused by variation in the acoustic characteristics of the layer.