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Ductile iron manhole square covers 

They are used in rural and cable pits. Since the diagonal of the square is significantly longer than each of its sides and when the cover is crunched up, it is easy to fall in to the pit along the diagonal direction of the pit head, causing safety risks. If the pit head is made into round or significantly smaller than the manhole cover, the square cover will not fall into the pit. It involves the issue of the maximum use and saving of the material. The use of the covers depends on the size of the pit head, and if it has to install a square cover with the area greatly larger than that of the pit head, then the effective of the use and practical value of the material of round covers is surely much better, which both save the material of the covers and ensure the safety of the pit head.

Generally square are used to better prevent the entry of rain and other liquids.

The main application areas of ductile iron pit covers: municipal roads, highways, communications, electricity, running water, residential quarters, schools and other various parks.

Installation of ductile iron square covers

In order to ensure the normal use of cast iron covers, pay attention to the installation quality, accuracy of size, firm installation, easy to open, and clean and pretty in appearance; and according to the technical specifications for inspection of cast iron covers, the following installation rules are made:

The brick masonry ID or length by width and square or round of the cast iron cover shall be determined in accordance with the size of the manhole cover designed by the design institute (if it is the best for construction according to the actual condition); and the reference standard can also be followed. It is important to note that the inner diameter of the pit head should be in accordance with the inner diameter of the cover during masonry of the pit and the cover shall be at the same level of the pavement after installation. After the pit seat is poured with concrete or asphalt, the cover should be opened in time to clean, to avoid the mortar or asphalt pouring the inspection cover together so as not to affect the future opening.

During the pit seat installation on the cement pavement, a ring beam with thickness of 20CM and Grade C25 concrete shall be poured and made flat on the masonry of the pit head; make sure that the four directions of the pit seat is maintained contact, the overall neat and smooth and not loose; a width of 40CM concrete protection ring shall be poured around the cover (if it is a concrete pavement, a width of 20CM concrete protection ring with reinforcement bars can be poured), and reinforced with steel) ; and the curing period is more than 10 days.

To maintain the pretty of appearance and surface pattern and words clear of the cover, it shall be covered with a thin metal sheet during construction of the asphalt pavement to prevent the asphalt oil sprayed on the cover; and during the concrete pavement construction, the plastic film shall be used to cover the covers properly to prevent the mortar from staining the surface of the covers and damaging the surface pattern and writing, or cleaning the covers surface with water after completion of the construction of the day.

When installing the cast iron covers on the asphalt pavement, be sure to avoid the construction machines from directly crashing on the pit seat; and during the integrated pouring of the pavement, a slightly larger hole shall be reserved on the pavement is cast as a whole, the holes which is slightly larger than the pit seat should be reserved, for installation after complete of the asphalt pavement. (For a full concrete road, the cover shall be installed after the second course stone is laid and compacted)to ensure the quality of manhole cover to extend the service life.

The users and construction companies shall pay attention to all items above; and the damage of the cover caused by improper installation or vehicle overload is not in the warranty scope of our factory that will not bear joint liability.