The use of ultrasound for investigation of glazing units

Abstract

The possibilities of determination of the composition of gas mixtures filling glazing units are investigated. It is shown that the concentration of air in the noble gas and air mixtures can be determined by measuring sound velocity inside the glazing unit. It is revealed that the temperature of noble gas and air mixtures must be evaluated, when the concentration of air is determined. It is shown, that the basic problem when using ultrasound method, is to get the ultrasonic signal from the glazing unit which is a multi-layer structure consisting from solids and gases. The acoustical parameters of noble gases are provided and suitable ultrasound methods for sound velocity measurement in the gas mixtures are discussed. The transmission coefficients of the transmitting and receiving transducers and of the glazing units, located in the gas media, are calculated. The contact echo methods are better as they are extremely convenient for investigation of the glazing units in the windows of the buildings. It is revealed that the application of longitudinal-shear waves in the glass panes gives the decreasing of the transmission losses and is more preferable for ultrasound measurements.