Control of milk quality parameters using ultrasonic waves in thin plates

The propagation of ultrasonic waves in thin plates/waveguides by immersing them in the milk, as an example of multicomponent fluid was investigated. Six samples of milk from one producer ( the nominal fat levels shown on the package were 0.5, 1.5, 2.5, 3.2, 3.5, 6.0 %) were taken to study. Principle parameters of the samples were analyzed using the analyzer MilkoScan FT120. The attenuation coefficients of the symmetric Lamb wave and horizontally polarized normal waves depending on the fat content of milk were measured with ultra-sonic viscodensitometer. Construction of the ultra-sonic viscodensitometer and its measuring device are described. Obtained from ultra-sonic measurements numeric values of the shear viscosity correlate well with measured values of the milk fat content. As far as calculation of milk density using ultra-sonic measurements with the aid of the Lamb waves is concerned were can say that though differences of the measured meanings from the meanings measured with MilkoScan FT 120 are small enough when compared with absolute value (not exceed 8 %) additional study is needed to interpret the results. The ultra-sonic measurements show that with increase of milk fat content density of the milk tends to grow (about 1 %) while the density corresponding to the measurements with MilkoScan FT 120 gives reverse dependence (decrease is 0.6 %). The experiments carried out demonstrated that application of waves in thin plates can considerably improve informativity of the existing ultra-sonic devices for control of milk quality. The propagation of ultrasonic waves in thin plates / waveguides by immersing them in the milk, as an example of a multi-component fluid, was investigated. The attenuation coefficients of symmetric Lamb waves and horizontally polarized normal waves depending on the fat content of milk were measured. Obtained from ultrasound measurements numerical values of the shear viscosity correlate well with the measured values of the milk fat content. The experiments showed that the use of waves in thin plates can significantly improve informativity of modern ultrasonic instruments for monitoring milk quality.

multicomponent fluid, concentration, milk quality, ultrasonic measurements, ultrasonic waves in thin plates