Large well covers are a bit like cement well covers, low cost, but poor quality, fragile and easily weathered. Usually, the weather starts before the cover is completed.
The recovery well cover is made of polyethylene and fly ash additives in waste plastic bags. The product has rough appearance, soft texture and easy stratification. And often because of its strength is not enough, especially thick.
Resin is made of resin and various additives. The products are delicate and beautiful, and can be colored freely. The bearing capacity is the strongest, and its cast iron is almost the same... But the price is the same as the national standard cast iron well cover, far higher than the other two. The steel fiber reinforced concrete manhole cover made of nonmetal manhole cover is an improved product of the original reinforced concrete manhole cover.
Recycled resin composite manhole cover is a synthetic resin based composite product made of fly ash and waste plastic, which is mixed in the molten state and formed by pressing. This kind of composite manhole cover is made of waste materials, without any steel or other recyclable materials, so it has the function of anti-theft. It can digest a lot of fly ash and waste plastics in the manufacturing process, which meets the requirements of national energy conservation and environmental protection policies, so it is called "green manhole cover".
Glass fiber reinforced plastic manhole cover is made of unsaturated polyester resin as raw material, glass fiber as reinforcement material and certain filler. Due to different technology, structural materials and reinforcement materials, the performance of manhole cover products is also very different. The domestic production of FRP manhole cover is generally as follows:
（1） Resin transfer molding process. Due to the high resin content, the manhole cover is not suitable for use on the carriageway due to the insufficient bearing capacity.
(2) Hand paste manufacturing process. Production efficiency is slow, not suitable for large-scale production, and there is no competitive advantage;
(3) Forming process. The forming process is laminated composite pressing under a certain temperature and pressure. The structure of this product is relatively compact. It uses different materials to check the well covers in different parts. Continuous fiber reinforcement is used in the lower part of the manhole cover to ensure its bearing capacity; filler is used in the middle part to improve the deformation capacity of the product and reduce the production cost; materials with high hardness and good wear resistance are used in the upper part to improve the compression resistance and wear resistance of the upper part of the product.
The composite well cover is made of unsaturated polyester resin as the matrix material, glass fiber as the reinforcement material, supplemented by certain rigid materials. The structure is made of pot bottom structure, and the bottom tensile strength material is uniformly distributed. The material is divided into two layers, the upper part is wear-resistant and anti-aging material, and the product has long service life.