Optical indicator for liquid level in tank - involves transparent blocks with V-shaped bottoms with lamp

摘要

The liquid level in a container is indicated by a bright or dull top surface of transparent blocks placed with their bottom at a known height above the tank bottom. Each block has a flat top surface, vertical sides on four faces and the bottom shaped in a symmetrical vee form. If the transparent material of the block has a refractive index less than that of the liquid in the tank, then incident light at the top surface will pass down the block and be totally reflected at the bottom of the block if it is submerged in the liquid, and then pass back up again to make the top surface bright.