Apparatus for sensing the level of contents in a container

摘要

The invention provides apparatus for sensing the level of contents in a container comprising a body (20); a diaphragm (50) having first and second faces; two probes (40) connected to the first face of the diaphragm for mechanical oscillation thereon; two actuating arms (54,56) fixed to the second face of the diaphragm each in a position opposite that at which a respective probe is fixed; and a stack (70) comprising one or more driving transducer and/or one or more receiving transducer, the stack functioning such that the or each receiving transducer generates a voltage in response to a change in compressive force between ends of the stack and such that a voltage applied to the or each driving transducer causes the length of the stack between its ends to change. Ends of the stack (70) are connected to the actuating arms (54,56), and are subject to a compressive force. Vibration of the probes (40) causes consequential vibration of the actuating arms (54,56) to cause modulation of the compressive force applied to the stack (70). <IMAGE> <IMAGE>