WAVEGUIDES IN ACOUSTIC SENSOR SYSTEMS

Waveguide sensors and buffers have been applied to measuring three of the four principal measurands of interest in industrial process control, namely, liquid level, flow, and temperature. Buffers are used when the measurand is at high temperature, which sometimes occurs in NDE/NDT situations. Waveguide sensors can also sense liquid density and viscosity. Problems include isolating the sought measurand from interfering variables, and eliminating acoustic or ultrasonic noise conveyed by a pipe or other structural element that acts as an unwanted waveguide, channeling interference to a transducer and reducing the signal to noise ratio at the transducer.