An ultrasonic system for detecting foreign contaminants in milk

Abstract

Detection of foreign objects is of paramount importance to the dairy producers as it is connected to the safety and quality of the product. Hence it is important to monitor foreign object using suitable methods. Non-invasive methods in that they are not in contact with the milk and as such they do not affect the ingredient and structure. This paper presents an investigation on the utilisation of an ultrasonic system to detect and image unwanted contaminants in milk. 16 ultrasonic transducers are installed around a 73 mm × 73 mm milk carton. Four transceivers are mounted at each side of a square-shaped sensor jig. A simulation was performed utilizing the COMSOL software in order to analyze the propagation of ultrasonic wave on objects having various densities. Among the variables investigated are acoustic impedance, attenuation, frequency, time-of-flight and amplitude. The samples used in this research are contaminants having different densities i.e. metal, glass, wood and plastic. Results show that the ultrasonic system can detect foreign objects in milk.