Abstract: A method for on-line acoustic detection of the quality of foams and aerated fluids whereby at least one emitter/receiver pair is placed in a close vicinity to the foam flow. At least one acoustic pulse is emitted and the time within which the acoustic pulse travels from the emitter to the receiver is recorded. Sound speed in the foam is determined by analyzing an acoustic response of the receiver and a pressure in the foam is also measured.

Abstract: A method and device for on-line foam quality acoustic monitoring are suggested. As per the invention, the method provides for the following: at least one emitter/receiver pair is placed in a close vicinity to the foam flow; at least one acoustic pulse is emitted; time, within which the acoustic pulse overcomes the way from the emitter to the receiver, is recorded; acoustic pulse speed (sound speed) is determined by analyzing an acoustic response of the receiver. After that, pressure in the foam in the area between the emitter and receiver is defined and the foam quality ? is calculated as per the equation: ? = 1 2 ± 1 4 - N ? fl ? p C fm 2 , where: Cfm—speed of sound in the foam, p—pressure, ?fl—fluid density, ?—foam quality, N—polytrophic expansion coefficient (N=1 for isothermal process; N=1.