FIELD: measurement technology; automatics. SUBSTANCE: first waveguide is positioned in liquid medium of reservoir. Then second and third waveguides are placed in the same reservoir according to its height. Elastic longitudinal waves of zero order are excited in all waveguides. They are received after passing through waveguides. Level of elastic wave intensity is measured in waveguides selected in pairs "second-first" and "second-third" of "first-third" and "second-third". Then relation of relative intensity levels of longitudinal elastic waves for selected pairs is determined. Second waveguide is insulated from liquid medium and third waveguide contacts liquid medium through its entire length. EFFECT: enhanced accuracy of measurements. 1 dwg
