Method and device for acoustic measurement of the specific density of a gaseous or liquid medium

A device for a measurement of a specific density of a gaseous or liquid medium, comprising:

• a transmitting transducer to inject a pulsed acoustic signal into the measured medium;
• a receiving transducer to detect an acoustic received signal after passing through a measured path in the measured medium;
• and
• an analytical device, wherein the acoustic impedance Z of the medium is automatically determined based on the design of the analytical device by comparison of the characteristic for the currently measured received signal with reference characteristics predetermined for various values of the acoustic impedance and stored so as to be associated with the respective value of the acoustic impedance, wherein the comparison is made in at least one temporal sub-domain of the characteristics, wherein the propagation speed c of the acoustic signal is determined in the medium and wherein the density ρ of the mediums is calculated as the quotient from the acoustic impedance Z and the propagation speed c,
• wherein the comparison is based on a linear regression, or
• wherein the comparison is based on a partial least squares regression, and
• wherein the signal is digitally processed in the analytical device using sampling rate which is between three and six times the resonance frequency of the transducers.

A method for measurement of the specific density of a medium, comprising:

• injecting a pulsed acoustic signal into the measured medium by a transmitting transducer;
• detecting the signal by a receiving transducer after passing through a measured path;
• determining automatically the acoustic impedance Z of the medium in an analytical device by comparison of the characteristic for the currently measured received signal with reference characteristics predetermined for various values of the acoustic impedance and stored so as to be associated with the respective values of the acoustic impedance, wherein the comparison is made in at least one temporal sub-domain of the characteristics;
• determining the propagation speed of the acoustic signal in the medium;
• and
• calculating the density of the medium as a quotient from the acoustic impedance Z and the propagation speed,
• wherein the comparison is based on a partial least squares regression, and
• wherein the signal is digitally processed in the analytical device using a sampling rate which is between three and six times the resonance frequency of the transducers.