Every day, when we move to the city, the cover of the sewer manhole continually gets into our field of vision. This object of the urban landscape since childhood has become so familiar and, I would even say prosaic, that, as a rule, we do not pay attention to it at all.
But in vain ... You never wondered why the hatches are round? Not square, not rectangular, not oval, but round?
I’m afraid that if this question did not arouse interest before, now you will definitely want to get an answer.
Section 1. Sewer manholes: polymer, cast iron, rubber, plastic. What role do they play?
First of all, it should be noted that they are an important component of any manhole, and they are installed directly in the housing. Moreover, this item must be placed in such a way that it fits snugly enough, and does not create obstacles either when hitting it, or during certain types of communication work.
If you look closely, you can see that each cover has an opening that is designed to measure the level of gas contamination of the well.
The lid is heavy, weighing from 50 kg. Moreover, such massiveness is not accidental, it is created deliberately in order to exclude any probability of its displacement. It should remain motionless even with very strong ground traffic.
Today in the CIS countries there is not only a massive theft of covers, but also their active delivery to scrap metal collection points. That is why it was decided to cover the hatches with special concrete slabs. However, this method carries a lot of disadvantages. Firstly, this coating is quickly destroyed, and secondly, when a car hits it, it simply turns into a potential danger, causing massive accidents.
Section 2. Trying to answer the question.
As it turned out, there are a lot of guesses in this regard, and in this article I will focus on three versions.
- Why are hatches round? The first explanation. Logical.
What would happen if such a cover had, say, a square shape? Well, actually, nothing terrible would have happened. Although to be honest, I am sure that this would cause some inconvenience. First of all, for purely geometric reasons. For a square lid, the diagonal size exceeds the length of the side, and therefore it can fall inward. With a round, even hypothetically this will not happen. It turns out that the latter is much safer, because it will not fall inside, which means that if an emergency occurs inside the collector, the workers will not suffer, and the car will remain unharmed without entering a hole that suddenly formed on the asphalt.
- Why are hatches round? The second explanation. Funny
Once I heard how tired, apparently, from a thousand “why?” young mother, tried to answer a similar question of the baby. She said something like this: “Well, the holes are round, you yourself see how else they can be covered?” I smiled and thought. But she is in principle right, only, and why then do not make square holes or is it just a coincidence? I asked a buddy architect. It turns out that a round sewer well is much easier to dig out, moreover, it turns out to be more technological, lasts longer and is not so much susceptible to transformation and temperature changes. Well, well, there is some truth in this interpretation too.
- Why hatches are round. The third explanation. Interesting.
Workers find this kind of lid easier to transport. Well, imagine that you need to move it from one place to another. If it were square, I would have to bear it, we would not have been able to do it ourselves, therefore, no less than 2 people would be involved, moreover, not weak men, because This item, as mentioned above, has a decent weight. But the round, if necessary, can easily be rolled. In addition, the round lid falls better on a specially designed place, because it does not need to be twisted, combining the necessary holes. And if you think about it, it’s easier to transport a circle safely than a square or a triangle: both arms and legs will be intact, and the edges of the hatch will not break off.