| CPC E03F 5/024 (2013.01) [E03F 2005/028 (2013.01)] | 9 Claims |

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1. A manhole cover seal, comprising:
a hollow body formed from an upper rigid shell, a lower rigid shell, spaced apart from said upper rigid shell and at least one stiffening rib extending between said upper and lower rigid shells, said hollow body having a cavity therein, and an outer periphery of said upper and lower rigid shells forming a rim on said body;
an expandable bladder, received in said rim, said expandable bladder in fluid communication with said cavity within said body, wherein said expandable bladder forms a watertight seal against a manhole frame when inflated;
a fill valve in fluid communication with said cavity; and
a drain hole positioned within said body to allow for controlled removal of accumulated water from the top of the seal, said drain hole including a gravity-based drain plug,
wherein fluid entering said fill valve increases a pressure within said cavity and causes said expandable bladder to expand to seal said manhole.
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