ABCD here refers to the load level in the color of the covers is a composite material.
Level A15 B125 C250 D400 E600 F900
Light Heavy Light Normal Heavy Light Normal Heavy.
Covers are used to cover up on the road or at home in deep defense was to prevent people or things falling generally divided into round and square, in the city of Highways in general, circular, because a circular covers easy to tilt, It can better protect the safety of pedestrians and vehicles.
Mainly on account of its center by a circular covers the length of each diameter are the same, so if the covers are rolled from passing vehicles, because no matter how rolling onwards, it will be slightly wider than the diameter of the wellhead below, covers not It will fall wellhead go.
Well grate is used in road rainwater drainage, filtration road trash, prevent blocking the sewer. Local roads using water drainage grate well.
In our material standard covers there are many, monolayer, bilayer, cast iron, ductile iron, composite, cement covers, steel fiber covers, cement covers and so on.