Patent ID: 6324901
Filing Date: 2001-12-04
Classification: G01N

Abstract:
A method of detecting the same or different foreign bodies in viscous or liquid foodstuff masses in receptacles in which said foodstuff masses contain lumpy particles by the reflection or absorption of sound, the method comprising the steps of:(a) conveying the foodstuff mass at a predefined speed through a measurement line section;(b) transmitting at least one ultrasonic signal having a predetermined amplitude through the foodstuff mass as the foodstuff mass passes through the measurement line section, said receptacles acting as a transmitting medium for acoustic signals;(c) receiving the transmitted ultrasonic signal after it passes through the foodstuff mass and any changes in the transmitted signal caused by reflection or absorption by a foreign body;(d) comparing at least one received ultrasonic signal with at least one transmitted ultrasonic signal;(e) detecting variations of at least one predetermined signal parameter between the received transmitted and reflected ultrasonic signal and the transmitted ultrasonic signal;(f) generating an activation signal when the variation in the pre-determined signal parameter exceeds or falls below a predetermined limit value; and(g) interrupting or diverting the transportation of the foodstuff mass when the activation signal is generated.