Float activated optical switch

A float activated optical switch for use with a remote light source and remote light detector, said float activated optical switch comprising a number of components, including a float, said float having a float interior;

• a first light guide connectable to a light source;
• a second light guide connectable to a light detector, said first and second light guides having distal ends positioned in said float interior and said distal ends being optically aligned but separated by a gap in said float interior;
• and a means to interrupt a light beam, said means to interrupt and adapted to removably occupy said gap between said distal ends of said first and second light guides;
• where said float interior lacks a powered light source and powered light detector, and where said float and said components positioned in said float interior are configured to be floatable in a desired fluid, said first and second light guides coupled to said float and adapted to follow and move with said float as said float moves from a first position, where said means to interrupt is positioned to allow light transmission between said distal ends of said first and second light guides, to a second position, where said means to interrupt is positioned to interrupt light transmission between said distal ends of said first and second light guides.

A method of detecting a level of a liquid in a tank comprising the steps of (a) deploying in a tank a float activated optical switch comprising a number of components, comprising a float having an interior, a first light guide, a second light guide, said first and second light guides having proximal and distal ends, said distal ends positioned in said float interior and said distal ends being optically aligned but separated by a gap contained in said float interior, and a means to interrupt a light beam, said means to interrupt a light beam adapted to removably occupy said gap, where said float interior lacks a powered light source and powered light detector and said float and said components positioned in said float interior being floatable in the liquid in the tank;

• (b) connecting said first light guide proximal end to a powered light source,
• (c) connecting said second light guide proximal end to powered light detector, said light source and said light detector are located remote from said float,
• (d) tethering said float activated optical switch to a fixed location in said tank;
• said float movable to a first position to allow light transmission between said distal ends of said first and second light guides, and to a second position, where said means to interrupt is positioned to interrupt light transmission between said distal ends of said first and second light guides, said first and second light guides bending between said distal and proximal ends in response to said movement of said float to said first position or said second position,
• (e) emitting a light from said light source for transmission by said first light guide, and examining said second light guide with said light receiver for the presence or absence of a light.