The development of sewer systems in each state took place in its own way. In recent years, only round-shaped models have been manufactured. Why?
What is a sewer hatch?
A sewer hatch means a hole in concrete or earth that provides access to underground utilities. This hole is always closed by a lid, a hatch, in order to avoid accidents. The hatch has another function - to prevent illegal entry into the underground communications system.
Types of sewer manholes
Covers are divided into types. On them there are various stamping, patterns. So, for example, the emblem of the state and propaganda slogans were depicted on the first sewer manholes. Now on the covers display the serial number, date and initials of the manufacturer. Sewer people emit:
- Plastic
- Iron;
- Rubber;
- Cast iron;
India is considered the leader in the manufacture of sewer manholes.
Why are manholes round?
For many years in a row they have been producing exclusively round hatches. There are several reasons for this:
- The cost of manufacturing a body for a round hatch is lower than any other shape (triangular, diamond-shaped, rectangular);
- Convenience of movement. The round hatch is much easier to move: you just need to put it with an edge and roll in the right direction;
- Round sunroof is easier to open. Any circle point in it is a concentration of stress.For example, all the lids to the cans are also only round;
- The round hatch will not fall into the sewer system. Any other form has a high probability of subsidence below a specified level;
- The cross section of the system pipes is round. It is logical to make the same form and cover, which closes the sewer system.
- A round (triangular, rectangular) object cannot be taken out through the round manhole cover.
In some countries, triangular sewer manholes are used. In Nashua (a city in the USA) and now underground systems are covered with triangular-shaped covers. The acute angles of the triangle indicate to the repair team the direction of the flow of wastewater. However, such hatches were recognized as hazardous to health, and their dismantling began.
The choice of a round shape of sewer covers is dictated by elementary practicality. These hatches last longer, they are resistant to environmental influences. Less material is used for manufacturing, they are cheaper. It is convenient to work if you need to get inside the sewer system, it is safe. The probability of subsidence of the round hatch is very small.
