High resolution and small volume automatic ultrasonic velocimeter for liquids

A method is described to precisely measure the sound velocity of liquids. T he construction of a resonator cell for the simultaneous measurement of a s ample liquid and a reference liquid is presented. The non-ideal properties of the cavity resonators are carefully considered for a superior evaluation of the resonance frequency data Also presented is a low-priced electronic set-up, designed for the computer-controlled determination of the complex t ransfer functions of the cavity resonators and also for automatic temperatu re monitoring and control. Possible sources of errors are discussed and som e representative results are presented in order to illustrate the repeatabi lity of the method and the accuracy of the sound velocity data relative to a reference liquid.