Why Luzhongbao 690×890×50 Ductile Iron Manhole Cover Adjusting Ring Has Become the Preferred Solution for Municipal Engineering
In urban road construction and maintenance engineering, the precise alignment of manhole covers with road surface elevation has always been a technical challenge affecting construction quality. Traditional manhole cover installations often result in protruding or sunken covers due to base settlement or changes in road surface elevation, seriously impacting traffic safety and road aesthetics. The Luzhongbao 690×890×50 Ductile Iron Manhole Cover Adjusting Ring, based on a modular design concept and precision manufacturing processes, achieves precise control of cover elevation through an adjustable structure design, effectively solving the technical bottleneck of coordinated deformation between the cover and the road surface. It has now become an important supporting product in new road construction and renovation projects.
This adjusting ring strictly complies with the GB/T23858 standard and is cast from QT500-7 grade ductile iron. The 690mm × 890mm rectangular size design fully considers the adaptation needs of various types of manhole structures. The standard 50mm height, combined with a multi-level adjustment groove design, allows a height adjustment range of ±20mm. The product features reinforced load-bearing structures at its four corners, and the ring body internally uses a radial rib layout, ensuring overall strength while achieving a lightweight design. The surface is treated with hot-dip galvanizing, with a zinc layer thickness exceeding 80μm, ensuring long-term durability in damp underground environments.
Precision Structure and Adjustment Mechanism
The core value of this adjusting ring lies in its precise adjustment system. The ring body is surrounded by multi-level stepped adjustment grooves, which, combined with dedicated height adjustment bolts, enable millimeter-level height fine-tuning. A unique wedge-shaped locking device allows rapid fixation of the ring body through rotating pressure blocks, effectively preventing displacement and deformation during construction. Laboratory verification shows the repeatable positioning accuracy of this adjustment system reaches ±0.5mm, fully meeting the flatness requirements of high-grade roads.
Material Characteristics and Process Assurance
The product selects QT500-7 ductile iron material. Its unique spheroidal graphite microstructure gives the material excellent mechanical properties. Tensile strength exceeds 500 MPa, yield strength is 320 MPa, and elongation exceeds 7%, fully adapting to the dynamic load requirements of the road environment. The casting process uses the lost foam method, ensuring precise product dimensions, a smooth surface, and a dense, defect-free internal structure. A special anti-deformation heat treatment process effectively eliminates casting stress, guaranteeing the product's long-term dimensional stability.
Load-Bearing Performance and Structural Design
The internal structure of the adjusting ring employs a grid-pattern reinforcement rib layout. The main ribs are 40mm high, supplemented by diagonal support structures, forming a stable spatial load-bearing system. Verified by national testing institutions, this structural design gives the product a load-bearing capacity reaching D400 grade, capable of withstanding test loads exceeding 400 kN. The mating surface between the ring body and the frame uses a labyrinth seal structure, combined with high-performance rubber sealing strips, effectively preventing sediment ingress and groundwater leakage.
Construction Convenience and Engineering Benefits
The modular design makes installation and adjustment extremely convenient, with installation time per unit not exceeding 30 minutes. The unique quick positioning system allows the adjusting ring to be pre-installed before the concrete pouring of the manhole structure, significantly shortening the construction period. According to engineering statistics, using this adjusting ring improves the efficiency of manhole cover elevation adjustment by more than three times and significantly reduces later maintenance frequency, lowering comprehensive construction costs by over 25%.
Durability and Anti-Corrosion Design
Through dual protection of hot-dip galvanizing and epoxy asphalt coating, the product's corrosion resistance is significantly enhanced. The zinc layer forms a metallurgical bond with the substrate, effectively blocking the erosion of corrosive media. Verified by a 192-hour neutral salt spray test, the product's protection reaches C5-M, with a design service life exceeding 30 years. A special edge chamfer design avoids stress concentration, improving the product's impact resistance.
Application Scenarios and Adaptation Performance
The standard 690×890×50mm size adapts to the vast majority of municipal manhole needs, being particularly suitable for new road construction, renovation, and maintenance projects. The product can be customized to special specifications according to actual needs, meeting construction requirements for different regions and different road grades. Its precise adjustment mechanism and reliable structural design make it a key component for improving road flatness.
Summary
The Luzhongbao 690×890×50 Ductile Iron Manhole Cover Adjusting Ring, with its precise adjustment mechanism, reliable structural design, excellent durability, and significant engineering benefits, has become an indispensable and important component in modern road construction. This product not only solves the elevation control challenges in traditional manhole cover installation but also, with its innovative design concept and comprehensive functional configuration, provides reliable assurance for improving road engineering quality. Choosing this product means injecting precise control capability and lasting performance assurance into the engineering project, which is the fundamental reason for its widespread recognition in the field of municipal engineering.
