1. Field of the Invention
The present invention relates to a manhole infiltration disk and filter assembly for locating and sealing a manhold cover assembly on the top of a manhole.
2. Description of the Prior Art
In my U.S. Pat. No. 4,368,893,issued on Jan. 18, 1983 and entitled Manhole Infiltration Disk and Seal Assembly, I disclosed and described a system for locating a manhole cover assembly on a manhole and for sealing the gap between the manhole and the manhole cover assembly. In the six or seven years of experience with this system, it has been noted that as the seal material hardens, sufficient water will infiltrate the gap causing upheavals as a result of the freezing and melting of the water. These upheavals allow foreign matter such as sand, soil and stones to accumulate in the gap between the disk and the manhole cover assembly which eventually creates an opening that will allow water to flow into the manhole. This problem was further compounded by the inclusion of a flange on the periphery of the inside diameter of the ring which created a trough with the accumulation of water, sand and soil, and increased the upheaval in the manhole cover assembly.
In storm manholes, catch basins and curb catch basins, the manhole cover assembly is installed with mortar on the top of the manhole cover assembly. After a short time the mortar starts to deteriorate and then sand, stone and ground start to leak into the manholes or catch basins. The overlying cement or black top then starts to break, crack and settle around the manhole cover assembly. Concrete and black top do not adhere to the manhole cover assembly, it always pulls away. This allows water to wash away the underlying sand, stones and ground which accumulate under the manhole cover assembly causing upheavels of the manhole cover assembly.