Why are the hatches round?

Roman Zhdanov
Roman Zhdanov
December 17, 2012
Why are the hatches round?

Every day, on the way to work, we walk down the street and every day we see sewer manholes in front of us, but we never think about it - why is the manhole cover round? But this is not by chance, and there are explanations for this. Let's find out and we.

In fact, not all sewers are round, only hatches located on the roadway have such a shape. The round shape is convenient because you can approach such a hatch from any side, and on the road, with heavy traffic, this is very important.

In addition, the circle is a geometric figure that has the largest area for a given perimeter, in other words, the rounded shape helps to save material, and if you take into account the mass of the hatches, the savings are quite tangible. From here follows another conclusion - the round hatch has the smallest mass with the same area, in comparison with other forms (square, oval, triangle, etc.). It is also worth remembering that the hatch closes the pipe, which has a rounded shape, and in this case with a round hatch the pressure on the pipe will be minimal,besides pressure on the round hatch is also distributed evenly.

Probably everyone saw how workers come with a lid open hatch. They throw it on the asphalt (it’s not necessary to scold them for it, since its weight is about 53 kg), the circle has no corners that could have been knocked together with such a blow, it is durable - this is one answer to the question - why sewers are round.

Recently, when the reception of metal was very popular in our country, cast-iron hatches were changed to concrete. Concrete is less durable, more cumbersome and, as planned, by the government, it should not have been stolen. The summer residents obviously did not agree with this statement of the government and quickly began to improve the dacha plots with sidewalks from concrete manholes. In the end, all returned to the cast iron.

But back to the topic and think - why the hatches are round? Perhaps the most important reason is security. It would not have tried, but you will not be able to throw a round manhole into the sewage system, but you can cheat with other forms. This reason seems strange - who would think of throwing a hatch down the drain? But believe me, there are a lot of people who want it.

These are the main reasons why hatch covers are made round.