Patent ID: 8994812
Filing Date: 2015-03-31
Classification: G01F,G02B

Abstract:
1. An optical sensor for detecting the level of a liquid in a container, particularly intended to equip a removable container of an electric household appliance, such as for example a liquid soap dispenser for a dishwasher or washing machine, the sensor comprising a photo emitting element and a photo receiving element carried side-by-side by a supporting and feeding element either associated or associable in use with a support for the container, in particular a frame of the electric household appliance, and a composite lens either associated or associable in use with the container, designed so as to remain immersed in the liquid contained in the container and facing the photo emitting and photo receiving elements; characterized in that the composite lens comprises: a first cylindrical body made of a light-permeable material, vertically mountable in use from the top of the container facing the photo emitting and photo receiving elements and up to a bottom wall of the container; and a second cylindrical body, arranged outside the first body and open towards the bottom wall; the second cylindrical body being delimited by a side wall arranged facing, and spaced apart from, a corresponding side wall of the first body, over the whole length of the latter, so that a predetermined annular clearance is present between the side walls of the first and second cylindrical bodies, the clearance being accessible in use by the liquid the level of which is intended to be measured, the side wall of the second cylindrical body being made so as to be at least partially reflecting towards the side wall of the first cylindrical body in such a manner that an attenuation of a radiation emitted by the photo emitting element and detected by the photo receiving element is proportional to the level of liquid present between the side walls of the first and second bodies, so that the level of liquid is optically measured without using floats.