Abstract: The invention relates to a mechanical barrier which prevents tampering with a filler pipe on an underground storage tank for gasoline, fuel, chemicals, or other valuable liquids. The barrier fits within a cylindrical metal liner that surrounds the filler pipe. The barrier includes two spaced posts with semi-circular brackets at their lower ends, for securement about the filler pipe. An annular plate is secured between the upper ends of the post. A lock fits into a cut-out in the plate. A plunger within the lock is extended through an opening at the upper end of one post to maintain the barrier in locked position around the filler pipe, to prevent unauthorized withdrawal of or tampering with the contents of the tank.

Abstract: The invention relates to a mechanical barrier which prevents tampering with a filler pipe on an underground storage tank for gasoline, fuel, chemicals, or other valuable liquids. The barrier fits within a cylindrical metal liner that surrounds the filler pipe. The barrier includes two spaced posts with semi-circular brackets at their lower ends, for securement about the filler pipe. An annular plate is secured between the upper ends of the post. A lock fits into a cut-out in the plate. A plunger within the lock is extended through an opening at the upper end of one post to maintain the barrier in locked position around the filler pipe, to prevent unauthorized withdrawal of or tampering with the contents of the tank.