The midsummer of Nanjing is also a "high-pressure period" for flood control. In these critical months, the city's pipe network is also facing a "big test". In the last issue of Approaching the "Blood" of the City, we introduced the daily health care of the sewage pipe network. However, these deep buried urban "blood vessels" face complex situations, which will inevitably lead to damage, cracking and other injuries. In this issue, we went to the "surgeon" team in the drainage facility operation center of Nanjing Water Group to see how they skillfully operated and patched the pipe network.
Don't underestimate the difficulties and miscellaneous diseases of urban blood vessels. The rooting of big trees will also damage the pipe network
"The normal operation of urban sewage pipelines requires routine maintenance, but there will also be problems that can not be solved by routine maintenance." The pipelines will have cracks, leakage, deformation or even collapse due to some complex reasons, and there is no way to solve this problem with normal dredging. This is like human blood vessels. Blockage and cracks are very serious problems, which will seriously affect the normal operation of the entire urban sewage facilities. " Yan Haixing, head of the maintenance section of the drainage facility operation center of Nanjing Water Group, explained. There is a special team in the center to deal with the diseases encountered by the pipeline. There are many and complicated reasons for the cracks and deformation of the pipeline, even the roadside trees will cause adverse effects. "We sometimes find that the roots of trees' hurt 'sewage pipes." Yan Haixing introduced that the places where each section of the pipeline is connected are relatively fragile. Once there are tree species nearby, the roots will continue to extend downward - it is hard to imagine the power of nature. The roots of trees growing downward can even grow into the drainage pipeline unconsciously. In this case, the root of the tree in the pipe is like a net, "blocking" the larger solid substances in the pipe, which will soon cause blockage. "At this time, professional equipment is required to enter the pipeline to cut the roots, and then repair the wound of the pipeline according to the damage."
Use "magic capsule" to reduce excavation, and see how to "patch" the pipe network
Pipeline repair is like patching clothes, but the "patch" of the pipeline is much stronger and more durable. The underground pipe network is complex and the space is narrow, while the drainage facility operation center of Nanjing Water Group has its own "secret weapon".
On July 17, at the intersection of Hexi Street and Lushan Road, a group of water workers wearing yellow vests and gloves were working in the slow lane under the scorching sun. The well cover of the sewage pipe network on one side has been opened, "There is a crack in this sewage pipe network, and we are preparing to repair it." A water worker said.
Yan Haixing told the reporter that the routine inspection and maintenance found a problem section, and the maintenance procedure should be started. The workers would block the pipe network openings at both ends of the section, drain the water in the pipeline, and "isolate" the problem section. Then, put the "robot" into the pipe to detect the problem pipe and find the "injured" position.
Now, it's time for the secret weapon to come out - this is a hollow steel column in the middle, with a rubber airbag wrapped on the outside. When the airbag is inflated, the middle will bulge and become a capsule. Yan Haixing said that before maintenance, the staff should specially make "patches". They will wind 5-6 layers of glass fiber on the surface of the rubber airbag, and each layer should be coated with epoxy resin and other "special glue" for bonding. Next, check the workers in the well and slowly guide the capsule into the pipe. When the air bag enters the injured part, it starts to inflate. Through the expansion of the air bag, the "patch" of the outer layer will fit the injured position of the inner wall of the pipe. After 40 to 60 minutes, it can be solidified to form a thick "film" inside the pipe, thus playing the role of repairing the water pipe.
Yan Haixing told the reporter that this technology can repair the problem pipeline underground, thus reducing the road excavation and the impact on the environment.
Post time: Nov-22-2022