Float activated optical switch

1. A float activated optical switch, comprising a number of components including a float, having an outer surface defining a float interior;

a powered light source;

a powered light detector, said light source and light detector located remote from said float;

a first light guide having proximal and distal ends, said first light guide connected to said light source;

a second light guide having proximal and distal ends, said second light guide connected to said light detector, said first and second light guides 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 a light beam adapted to removably occupy said gap in said float interior;

said float and said components positioned in said float interior being floatable in a desired liquid, said first and second light guides coupled to said float and adapted to bend between said distal and proximal ends with movement of said float 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.

2. The float activated switch of claim 1 wherein said float interior is sealed from an environment exterior to said float interior.

3. The float activated optical switch of claim 1 further having a separator assembly component in said float interior and having a hollow interior portion, said distal ends of said light guides being located in said separator assembly, said gap separating said distal ends of said light guides being located in said separator assembly hollow interior portion.

4. The float activated optical switch of claim 1 wherein said means to interrupt a light beam comprises an optically opaque device that is slidable in said gap.

5. The float activated optical switch of claim 1 wherein said means to interrupt a light beam comprises an optically opaque device that is rollable in said gap.

6. The float activated optical switch of claim 1 wherein said first and second light guides are contained in a cable, said cable being sealingly positioned in said float.

7. 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.

8. The float activated switch of claim 7 wherein said float interior is sealed from an environment exterior to said float interior.

9. The float activated optical switch of claim 7 further having a separator assembly component, said separator assembly located in said float interior and having a hollow interior portion, wherein said distal ends of said light guides are located in said separator assembly and said gap, separating said distal ends of said light guides, is located in said separator assembly hollow interior portion.

10. The float activated optical switch of claim 7 wherein said means to interrupt a light beam comprises an optically opaque device that is slidable in said gap.

11. The float activated optical switch of claim 7 wherein said means to interrupt a light beam comprises an optically opaque device that is rollable in said gap.

12. The float activated optical switch of claim 7 wherein said first and second light guides are contained in a cable, said cable being sealingly positioned in float.

13. 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.

14. A method of detecting a level of a liquid in a tank of claim 13 wherein said float interior is sealed from an environment exterior to said float interior.

15. A method of detecting a level of a liquid in a tank of claim 13 wherein said float activated optical switch further comprises a separator assembly in said float interior and having a hollow interior portion, said distal ends of said light guides being located in said separator assembly, said gap, separating said distal ends of said light guides, being located in said separator assembly hollow interior portion.

16. A method of detecting a level of a liquid in a tank of claim 13 wherein said means to interrupt a light beam comprises an optically opaque device that is slidable in said gap.

17. A method of detecting a level of a liquid in a tank of claim 13 wherein said means to interrupt a light beam comprises an optically opaque device that is rollable in said gap.