The manhole cover in Hebei has been showing injuries and deaths caused by broken, stolen or washed-out water covers all over the country. So where does the manhole cover spread in the city? How to distinguish which manhole covers are sewage manhole covers?
Yesterday, a popular science post about the condition of a well on the road was circulated on Weibo, and its layout rules were popularized. Weibo said: Sewer wells are mainly scattered in the center of the main road or the neighborhood of the residential building, while telecommunication, gas, communication cables, heat, septic tanks and other manhole covers are usually on the sidewalk. In response, the reporter interviewed Mr. Song, an engineer from a design institute in Dalian, who echoed the concept of Weibo.
Some people will question what raw materials are used to make the manhole cover. Can it be washed away? The reporter checked the information on the Internet and learned that there are many specifications for manhole covers in China, such as single-layer, double-layer, cast-iron, and cement. There are different uses based on different occasions. Oasis and crosswalks are all lightweight. To cross the road of a motor vehicle, you must use heavy. What is the load bearing capacity of a heavy sewer cover? It is understood that the pressure of such heavy manhole covers can reach about 30 tons; on the auxiliary road, only ordinary manhole covers need to be installed, and the pressure of such manhole covers can be about 10 tons.
What is the primary function of the sewer?
For ordinary repairs and unblocking of the pipe network
Why is the sewer well in the center of the road? What is its primary function? Mr. Song introduced that the sewer well is located at the center of the main and secondary roads, one is to drain rainwater and sewage; the other is to facilitate the repair. Once the water is flooded, the drainage system is blocked, making it easier for construction workers to repair and clear the pipe network.
In fact, the method of drainage on the road is to pass the sewage dumplings on both sides of the road to the underground sewage pipe network in the city, and then flow to the urban river through the sewage pipe network. "The road is slightly arched. When it rains, the rainwater flows along the road to both ends, flows through the sewage rafters into the sewage pipe, and then converges to the main pipe (the main pipe is usually located at the center line of the road) and then drains to City river. "Mr. Song explained.
Why is the manhole cover round?
Circular manhole covers do save data.
Good load bearing, manhole cover is not easy to fall into the well
There are many types of manhole covers on urban roads. In addition to sewer manhole covers, there are also tap water, telecommunications, gas, communication cables, heat, and septic tank manhole covers. "Not all manhole covers are circular. Generally speaking, the sewage manhole covers are mainly circular, while the heating wells are square." Mr. Song said that the difference between the wells depends on the symbol on the manhole cover. The words "rain" or "dirty" are usually written on the manhole cover.
Why choose a round manhole cover? "The shape of the well cover depends first on the shape of the well." Mr. Song said, as for the selection of the shape of the well, the most important thing is to look at the function of the well and its internal equipment, if it is a long series of valves located on the pipeline. , Conversion parts, etc., a long thing must be made into a rectangular well, making a circle is both labor and material.
Mr. Song indicated that the use of round wells in the center of the road is more about the bearing capacity of round manhole covers, and then the diameter of each mandrel passing through its center is the same. If the manhole cover is rolled up by the passing vehicle, Will fall into the wellhead. Another point is that the breakout hole of the sewer well must leave space for one person to pass, and the cross section of a person climbing down the ladder is basically round, so the circle naturally becomes the breakout hole of the sewer well. shape. "In addition, circular manhole covers do save data, but we don't think from this point of view."
Why use a round well in the center of the road?