Why the lid of the sewer is round and not the other shape

Because each of the circles is equal in diameter, if the manhole cover is made into a circle, the cover will not fall into the well from any angle.

There will always be one with the longest inner diameter in other shapes, such as a rectangle, whose diagonal is longer than the side length, and if the manhole cover is made into a rectangle, it is very likely to fall from the angle of the diagonal.

So the manhole cover of the sewer is always made round.

1.The hole under the lid is round, as the cylindrical shape best withstands the pressure of the surrounding land. Moreover, sewer access holes meant that there was enough space for one person to pass through, and the cross-section of a person climbing down a ladder was basically round.

So the round shape naturally becomes the shape of the sewer access hole. The round manhole cover is only to cover the circular opening.

2.Regarding the problem of the manhole cover circle, it can be traced back to France in the 13th century, when France was building Paris, considering the problem of building sewers, some people proposed to rebuild the cellar as a sewer, because the French winemaking was every household at that time, almost every family had a winemaking cellar, because there was a round hole in the ground for transporting the cellar of winemaking oak barrels, in order to avoid danger, these caves used round discus as manhole covers. Until the Roman Empire used French sewer technology in the construction of the city of Rome, major cities around the world used Roman sewer technology.

3.In fact, sewer covers are also square and rectangular.

4.Because the sewer is round, the manhole cover must be round.

Here's why:

1.In the case of equal circumference, the area of the circle is the smallest, so the circular manhole cover saves materials;

2.The circle has a unique symmetry, so it is easier to coincide with the sewer when the round manhole cover is covered;

3.The circle is closer to the cross-section of the human body, and it is more convenient for people to enter the sewer during maintenance.

Can be connected to the pumping pipe The pumping nozzle is round, how to connect the square?

1. Because the circle is round no matter how it turns, it will not fall down because of which side is narrower, 2, it is easy to transport, you can roll, 3, it saves materials, the same large area, and uses less material, 4, the sewer mouth causes a circle to reduce the probability of irregular objects (bicycles, stones, etc.) falling down after the sewer cover is stolen.

5. The round shape can reduce the possibility of pedestrians falling down due to lookout after the sewer cover is stolen, because the woman is round, the eyes are round, and the sewer mouth is also round, which can reduce the eye fatigue and body fatigue caused by the uneven force of looking at other shaped objects, thereby reducing the possibility of falling into the sewer, in short, there are many benefits.