Patent ID: 7883290
Filing Date: 2011-02-08
Classification: E02D

Abstract:
1. A security barrier system for attachment to a manhole bordered by an outer ring a shaft extending downwardly therefrom, the barrier assembly comprising: a sub-ring affixed to the manhole at or below the outer ring of the manhole, the sub-ring having a hole through a center thereof; a pan at least partially covering the hole of the sub-ring and being secured to the sub-ring; a manhole cover that is mounted on the outer ring of the manhole over the pan in a spaced apart relationship relative thereto; and a locking assembly that releasably locks the pan to the sub-ring, the locking assembly including a stop; wherein the locking assembly, the manhole cover, the sub-ring, and the pan are configured such that, when the locking assembly is engaged to thereby lock the pan to the sub-ring and the manhole cover is mounted in place over the pan, a gap is formed between the sub-ring and the stop of the locking assembly such that the pan can move upwardly a limited amount with respect to the sub-ring by an amount, as defined by the gap, that is sufficient to allow for the liquids to flow from the manhole from below in a back-up situation.