Ductile iron manhole covers are welded from flat steel and twisted square steel or flat steel and flat steel. Let ’s introduce their characteristics
1. It has the advantages of beautiful appearance, drainage, high strength, many specifications and low cost.
2. With the development of science and technology, resin or plastic is used as the reinforcement and inorganic filler is used to form a brand-new ductile iron manhole cover . The advantage is light.
4. Good bearing capacity.
5. Drainage: The leakage area reaches 83.3%.
Three points for installation of ductile cast iron manhole cover:
①: In order to ensure the fundamental strength requirements, before installing the rainwater rafters, a concrete foundation must be placed before the rainwater rafters are installed.
②: After installing the rainwater rafters, install fastening screws around them, and fill the bottom of the frame with cement mortar to prevent rainwater rafters from falling off for various reasons.
③: Eccentric rainwater rafters of any shape can be installed according to the actual situation. To achieve the actual requirements, the brickwork of the manhole cover should be determined according to the size of the manhole cover designed by the design institute. Sample application is good), can also be implemented with reference to standards accordingly. And a concrete protection ring with a width of 40cm is cast around the periphery of the manhole cover (if it is a cement pavement, a concrete protection ring with a width of 20cm can also be cast and reinforced with steel bars). The maintenance period should be more than 10 days.
2. When installing a manhole cover on an asphalt pavement, care must be taken to avoid the construction machinery directly rolling over the well seat. When the pavement is integrally cast, a hole slightly larger than the well seat should be reserved on the road surface and placed after the asphalt is paved.
3. In order to maintain the beautiful appearance of the cover, and the surface pattern and handwriting are clear, the manhole cover should be covered with iron sheet or wooden board during the construction of asphalt pavement. The black manhole cover can also be painted with waste engine oil to prevent the asphalt from spraying on the manhole cover. During the construction of cement pavement, cover the manhole cover with plastic film to prevent the cement mortar from contaminating the surface of the manhole cover and damaging the surface pattern and handwriting. The surface of the well cover can also be cleaned with water at the end of the day.
4. After the well is cast or the asphalt is laid in concrete, the well cover should be opened and cleaned in time to avoid the mortar or asphalt from pouring the inspection well cover and the seat into one body, so as not to affect the opening in the future. The above items should be noted by the construction unit.
1. Before installation, the foundation of the manhole cover shall be neat and firm, and the inner diameter and length and width shall be determined according to the size of the manhole cover.
2. When installing a composite manhole cover on the cement pavement, pay attention to the use of concrete pouring on the masonry of the wellhead, and also establish a concrete protection ring on the periphery for maintenance for about 10 days.
3. When installing composite manhole covers on asphalt pavements, care should be taken to avoid direct crushing of manhole covers and manholes by construction machinery to avoid damage.
4. In order to maintain the beauty of the manhole cover, as well as the clarity of the handwriting and patterns, be careful not to stain the manhole cover when pouring asphalt and cement on the road surface.
5. Wellhead, reinforced well circle and well frame must match.
6. Before installing the manhole cover, carefully check whether the type, size and structure of the manhole cover meet the design standards, and check for damage, cracks and other phenomena.
7. The installation of well frame, well cover and accessories must be firm, stable and in the correct position. It should be intact.
8. Commercial concrete must be used for pouring. When the concrete curing time is insufficient, early-strength and quick-setting concrete should be used. The concrete must be compacted and compacted with the road structure.
9. Do not disturb the surrounding pavement structure when excavating and removing the surface and base materials at the wellhead location.
10. Before the well circle is poured, the well frame is stabilized according to the measured elevation; the inner mold of the wellhead must use a fixed formwork.
11 There should be no less than 6 embedded bolts; if the embedded bolts cannot be installed, the well frame must be reinforced by other methods, such as expansion bolts or steel mesh.