Wide beam clamp-on ultrasonic densitometer

A method for determining the density of an unknown liquid in a pipe using an ultrasonic measuring device comprising a transmitter transducer, a reference receiver transducer disposed adjacent to the transmitter transducer, and a primary receiver transducer disposed at a predetermined distance from the reference receiver transducer, wherein the method comprises the steps of:

• transmitting a sonic energy wave, or signal, by the transmitter transducer through a pipe wall at a known rate without any liquid in the pipe, wherein the signal travels from the transmitter transducer to the reference transducer and then the signal reflects off the pipe wall to the primary receiver transducer;
• determining the ratio of amplitude of the signal detected by the primary receiver transducer relative to the amplitude of the signal detected by the reference receiver transducer;
• feeding a reference liquid with known sonic impedance into the pipe system;
• transmitting a second signal;
• determining the ratio of the amplitude of the second signal detected by the primary receiver transducer relative to the second signal detected by the reference receiver transducer;
• flowing through the pipe an unknown liquid;
• transmitting a third signal;
• determining the ratio of the amplitude of the third signal detected by the primary receiver transducer relative to the amplitude of the third signal detected by the reference receiver transducer;
• measuring the liquid sonic propagation velocity of the unknown liquid flowing through the pipe;
• determining the impedance of the unknown liquid the based upon the impedance of the reference liquid and the determined ratios;
• and
• determining the density of the unknown liquid based upon the determined impedance of the unknown liquid and the measured liquid sonic propagation velocity of the unknown liquid flowing through the pipe.

A system for measuring density of a liquid, comprising:

• an ultrasonic transducer system coupled to a pipe, the ultrasonic transducer system including a transmitter transducer coupled to the pipe which generates and transmits sonic energy waves at a known desired rate, a reference receiver transducer coupled to the pipe and disposed adjacent to the transmitter transducer for receiving the sonic energy waves, and a primary receiver transducer coupled to the pipe and disposed at a predetermined distance from the transmitter transducer for receiving the sonic energy waves;
• a sensor for measuring an amplitude of the sonic energy waves at the reference receiver transducer and the primary receiver transducer;
• and
• a processor means for recording the measured amplitude of the sonic energy waves at the reference receiver transducer and the primary receiver transducer and determining the ratio of the amplitude of the sonic energy waves received at the primary receiver transducer to the amplitude of the sonic energy waves received at the reference transducer for an empty pipe and for each of a plurality of fluids successfully fed into the pipe, one being an unknown liquid having an unknown density and sonic impedance, and for computing and recording the liquid sonic propagation velocity of the unknown liquid, and using the determined ratios and the liquid sonic propagation velocity of the unknown liquid to determine the density of the unknown liquid.