Method and apparatus for measuring acoustic parameters in liquids using cylindrical ultrasonic standing waves

Apparatus for measuring acoustic parameters of a fluid, the apparatus comprising:

• at least one pair of tubular cells;
• means for generating acoustic oscillations within the cells so as to produce a cylindrical mode of oscillation in at least one cell:
• means for detecting cylindrical-mode oscillations in the cells;
• and
• means for providing, based on the detected cylindrical-mode oscillations, an acoustic parameter measurement;
• wherein the mode of oscillation is a cylindrical standing wave:
• said apparatus further comprising:
• a first chamber, housing a first tubular cell, for receiving a reference liquid;
• a second chamber, housing a second tubular cell, having an inlet and an outlet defining a fluid pathway through the cell;
• a conduit for carrying a continuous flow of liquid through the second chamber;
• measurement means for measuring at least resonance frequency;
• and
• control means, coupled to the feedback means and the measurement means, for controlling the signal to maintain a cylindrical ultrasonic standing wave through each cell and performing at least one measurement thereon.

Apparatus for measuring acoustic parameters of a fluid, the apparatus comprising:

• at least one pair of tubular cells;
• means for generating acoustic oscillations within the cells so as to produce a cylindrical mode of oscillation in at least one cell;
• means for detecting cylindrical-mode oscillations in the cells:
• and
• means for providing, based on the detected cylindrical-mode oscillations, an acoustic parameter measurement;
• wherein the mode of oscillation is a cylindrical standing wave;
• said apparatus further comprising:
• a first chamber, housing a first tubular cell, for receiving a reference liquid;
• a second chamber, housing a second tubular cell, having an inlet and an outlet defining a fluid pathway through the cell;
• a conduit for carrying a continuous flow of liquid through the first and second chambers;
• means for establishing a predetermined temperature difference between the first and second chambers;
• measurement means for measuring at least resonance frequency;
• and
• control means, coupled to the feedback means and the measurement means, for controlling the signal to maintain a cylindrical ultrasonic standing wave through each cell and performing at least one measurement thereon.

Apparatus for measuring acoustic parameters of a fluid, the apparatus comprising:

• at least one pair of tubular cells;
• means for generating acoustic oscillations within the cells so as to produce a cylindrical mode of oscillation in at least one cell;
• means for detecting cylindrical-mode oscillations in the cells;
• and
• means for providing, based on the detected cylindrical-mode oscillations, an acoustic parameter measurement;
• wherein the mode of oscillation is a cylindrical standing wave;
• said apparatus further comprising:
• a first hollow resonator enclosure having a face and housing a first tubular cell for receiving a reference liquid;
• a second hollow resonator enclosure housing a second tubular cell and having a face oppositely oriented with respect to the face of the first hollow resonator enclosure so as to form a fluidic pathway through both of said enclosures;
• a membrane filter extending across the fluidic pathway between the enclosures;
• measurement means for measuring at least resonance frequency;
• and
• control means, coupled to the feedback means and the measurement means, for controlling the signal to maintain a cylindrical ultrasonic standing wave through each cell and performing at least one measurement thereon.