There are many types of well covers, including single-layer, double-layer, cast iron well covers, ductile iron well covers, composite well covers, cement concrete well covers, etc。 Among them, nodular cast iron manhole covers are most widely used。
Setting occasions of common ductile iron manhole cover grade mark:
Type I: (at least type A15): greenbelt, sidewalk and other areas to prevent flexible vehicles from entering.
Type II: (at least type B125): sidewalk, non motor vehicle, parking lot and underground parking lot
The third type: (at least C250 type): Residential Area North Street, cold lane, area only driven by light vehicles or small cars, passing through the curbs within 0.5m on both sides.
The fourth category: (at least D400 type): urban trunk roads, expressways, expressways and other areas。
Well covers are usually divided into round and square. In urban expressway, the round cover is usually used, because it is not easy to tilt, and can better protect the safety of pedestrians and vehicles.
Advantages of using round ductile iron manhole cover
The use of round nodular cast iron manhole covers is mainly based on the same diameter and length of each round manhole cover passing through its center, so if the manhole cover is rolled up by passing vehicles, its diameter will be slightly wider than the hole below, and the manhole cover will not fall into the wellhead. However, if the square is adopted, the diagonal of the square is obviously longer than the length of both sides, so when the well cover is rolled up, it is easy to fall into the well along the diagonal of the wellhead, causing potential safety hazards.
If the wellhead is round or obviously smaller than the manhole cover, the square manhole cover will not fall into the well. This involves the problem of using and saving materials to a large extent. The use of the wellhead depends on the size of the wellhead. If it is necessary to install a square well cover with a much larger area than the wellhead, the utilization and practical value of the material will not be more effective than the direct use of the round well cover, which not only saves the material of the well cover, but also ensures the safety of the wellhead. However, in rural areas and cable wells, squares are often used, which can better prevent liquid, such as rainwater, from entering.