In the present invention a controllable acoustic source (14) in connection with the process fluid (10) emits a signal (18) into the fluid (10), consisting of a suspension of particles (12), being volumes of gas, liquid or solid phase. The controllable acoustic signal (18) is allowed to interact, with the particles (12), and the acoustic (pressure) signals (22) resulting from such an interaction is measured preferably via a sensor (24). A spectrum is measured. The spectrum is used to predict properties, content and/or size of the particles (12) and/or used to control a process in which the process fluid (10) participates. The prediction is performed in the view of the control of the acoustic source (14). The used acoustic signal has preferably a frequency below 20 kHz.

In the present invention a controllable acoustic source (14) in connection with the process fluid (10) emits a signal (18) into the fluid (10), consisting of a suspension of particles (12), being volumes of gas, liquid or solid phase. The controllable acoustic signal (18) is allowed to interact, with the particles (12), and the acoustic (pressure) signals (22) resulting from such an interaction is measured preferably via a sensor (24). A spectrum is measured. The spectrum is used to predict properties, content and/or size of the particles (12) and/or used to control a process in which the process fluid (10) participates. The prediction is performed in the view of the control of the acoustic source (14). The used acoustic signal has preferably a frequency below 20 kHz.

System and methods for determining a non-condensable gas parameter relating to the amount of non-condensable gas within a variable flow rate fluid flow containing both non-condensable gas and condensate are disclosed. An apparatus may include a measurement tube for receiving the fluid flow and arranged such that the fluid flow through the measurement tube comprises alternating sections of non-condensable gas and condensate; a flow sensor for generating a flow rate signal relating to the flow rate of the fluid flow in the measurement tube; a phase sensor for monitoring over time the alternating sections of non-condensable gas and condensate flowing through the measurement tube and arranged generates a phase signal characteristic of the said sections monitored; and a non-condensable gas determining unit configured to determine a non-condensable gas parameter relating to the amount of non-condensable gas in the fluid flow based on the flow rate signal and phase signal.

System and methods for determining a non-condensable gas parameter relating to the amount of non-condensable gas within a variable flow rate fluid flow containing both non-condensable gas and condensate are disclosed. An apparatus may include a measurement tube for receiving the fluid flow and arranged such that the fluid flow through the measurement tube comprises alternating sections of non-condensable gas and condensate; a flow sensor for generating a flow rate signal relating to the flow rate of the fluid flow in the measurement tube; a phase sensor for monitoring over time the alternating sections of non-condensable gas and condensate flowing through the measurement tube and arranged generates a phase signal characteristic of the said sections monitored; and a non-condensable gas determining unit configured to determine a non-condensable gas parameter relating to the amount of non-condensable gas in the fluid flow based on the flow rate signal and phase signal.

Acoustical methods and an associated device, to estimate one or more properties of bubbles in a liquid like medium are provided. Principally, the acoustical method comprises acoustically exciting one or more bubbles in a liquid like medium to oscillate at a resonant frequency, detecting a first signal emitted from an acoustical source arranged to acoustically excite the one or more bubbles and detecting a second signal produced from the one or more bubble oscillations, deriving at least a first and a second characteristic by performing frequency domain analysis on the detected first and second signals, the first characteristic comprising a frequency interference minimum f.sub.1min and the second characteristic comprising a bubble resonance fundamental frequency maximum f.sub.1max and estimating one or more bubble properties from at least the first and second characteristics. Further provided are acoustical methods to estimate the equilibrium size and location of one or more bubbles in a liquid-like medium.

Acoustical methods and an associated device, to estimate one or more properties of bubbles in a liquid like medium are provided. Principally, the acoustical method comprises acoustically exciting one or more bubbles in a liquid like medium to oscillate at a resonant frequency, detecting a first signal emitted from an acoustical source arranged to acoustically excite the one or more bubbles and detecting a second signal produced from the one or more bubble oscillations, deriving at least a first and a second characteristic by performing frequency domain analysis on the detected first and second signals, the first characteristic comprising a frequency interference minimum f.sub.1min and the second characteristic comprising a bubble resonance fundamental frequency maximum f.sub.1max and estimating one or more bubble properties from at least the first and second characteristics. Further provided are acoustical methods to estimate the equilibrium size and location of one or more bubbles in a liquid-like medium.

A photoacoustic gas sensor device for deter-mining a value indicative of a presence or a concentration of a component in a gas comprises a substrate and a measurement cell body, the substrate and the measurement cell body defining a measurement cell enclosing a measurement volume. A reflective shield divides the measurement volume into a first volume and a second volume. An opening in the measurement cell is provided for a gas to enter the measurement volume. In the first volume and on a front side of the substrate are arranged: An electromagnetic radiation source for emitting electromagnetic radiation through an aperture in the reflective shield into the second volume; and a pressure transducer communicatively coupled to the second volume for measuring a sound wave generated by the component in response to an absorption of electromagnetic radiation by the component. At least a portion of a surface of the reflective shield facing the second volume is made of a material reflecting electromagnetic radiation.

This disclosure relates generally to a method and system for determining viscosity information of fluids. The present disclosure utilizes an intensity modulated continuous wave (CW) laser diode-based PA sensing method to obtain a continuous wave photoacoustic (CWPA) spectra. Through this CWPA spectra, a full width half maximum (FWHM) and a spectral area is determined to obtain the information about the viscosity of fluids. Although, the CWPA based sensing technique is used for distinguishing different types of abnormalities in tissues, so far it is not used for measuring viscosity which is an important thermo-physical property. The viscosity information of the fluids from the normalized Gaussian fitted CWPA spectra is based on a viscosity feature computed from a FWHM, and a spectral area. The viscosity feature improves the good of fit parameter (R.sup.2) significantly to 0.98 as compared to the traditional only FWHM based viscosity determination for which R.sup.2 is 0.91.

The invention discloses methods for simultaneously measuring various properties of a fluid using a waveguide. The method includes transmitting a plurality of wave modes into the fluid using an ultrasonic shear wave transducer from one end of a waveguide. Further, the wave modes are reflected from the other end of the waveguide. The reflected wave modes are processed simultaneously. The time of flight and the amplitude of the received wave modes are determined. Further, one or more properties of the fluid are measured using determined time of flight and amplitude of the received wave modes. The disclosed method is used to accurately measure the properties of fluid such as level, density, viscosity or flow rate in a short period of time.

The invention discloses methods for simultaneously measuring various properties of a fluid using a waveguide. The method includes transmitting a plurality of wave modes into the fluid using an ultrasonic shear wave transducer from one end of a waveguide. Further, the wave modes are reflected from the other end of the waveguide. The reflected wave modes are processed simultaneously. The time of flight and the amplitude of the received wave modes are determined. Further, one or more properties of the fluid are measured using determined time of flight and amplitude of the received wave modes. The disclosed method is used to accurately measure the properties of fluid such as level, density, viscosity or flow rate in a short period of time.