Thinking about two children in Baiyin setting off firecrackers on a manhole cover and being blown away by the air wave.

First, from the observation of the picture, the parents were completely unaware of the danger of flammable gas in the manhole cover. They were walking far behind, watching the two children playing with firecrackers, and did not know how to stop them until the tragic danger. occur.

Second, especially primary school students are very active and like to play with firecrackers. They like to light them in various spaces. They are easy to explode under stones and porcelain. Nowadays, firecrackers have a very strong impact and are very dangerous. .

What is the danger when a cannon is fired off a manhole cover? Let me tell you, I hope to see more publicity for this article.

After lighting the firecrackers and inserting them through the small hole in the manhole cover, the manhole cover will be blown up. There are two situations:

First, if the power of the cannon is relatively large, There was relatively little combustible gas in the well, and the cannon blew up the manhole cover, but the hazard was not high enough to throw the child into the air.

In the second type, the power of the cannon is relatively small, and there is a lot of combustible gas in the well. Especially when the mixing ratio of combustible gas and air reaches the explosion limit, the impact force can be very large.

Domestic sewage, feces and other organic matter in sewage wells decompose to produce methane and other combustible gases, commonly known as biogas. Just like gas in a mine, when there is no open flame, it will slowly dissipate to other places, and may cause an explosion when encountering an open flame. When the mixing ratio of methane and air reaches the optimal limit for explosion, the explosive power is quite large.

The size of the explosion is also related to the shape, location and size of the pipes in the sewage. If the gas accumulated in the pipes has no other dissipation channels, it will expand rapidly and explode when encountering an open flame.

Special reminder: People with bad habits such as stuffing cigarette butts in manhole covers, throwing firecrackers, and matches should pay special attention. These behaviors may lead to harmful consequences.