Why is the lid of the sewer round?
The diameter of the circle is only one, so the circular well cover rotates at the well mouth and will not fall into the well mouth. And square covers, whether square length or rectangular length or width, are necessarily smaller than the diagonal length, if the square covers are standing on the wellhead, it is easy to fall into the wellhead;
It can cover the well head from any angle. The square must be adjusted to the same angle as the wellhead;
1, because the circle, regardless of Lang, is round, not because of which side of the narrow point will fall,2, transportation is convenient, you can roll,3, save materials, the same large area, with less material,4, the water level crossing can cause the possibility of falling off the irregular objects (bicycles, stones, etc.) after the stolen cover is stolen.5, can reduce the possibility of circular sewer cover was stolen and looking down for pedestrians, because the woman is round, eyes are round, sewer mouth is round, can reduce the shape of the object and other eyes due to uneven stress caused by eye fatigue and body fatigue, thereby reducing the possibility of sewer pipes in short, there are plenty of benefits
Because if it's Square, square or oval, it's easy to fall into the underpass! But with a round lid, this can be avoidedOf course, there are also the following reasons: the circular lid can save material, increase the size of the hole, and the strength of the manhole cover and the well seat is increased, it is not easy to roll.
