Long rehabilitation together material security covers and rain grates are polymer composite-plastic composite materials. Compared with the traditional cast iron, cement, glass, steel, magnesite manhole covers, security covers of composite-plastic composite materials to overcome the cast iron, cement and other covers, structural performance is poor, fragile, easy to steal, noise, Kai cover the labor intensity big appearance stale disadvantages. And the following obvious advantages: 
 (A) High intensity: the high molecular weight compound plastic composite materials, with high compressive strength, flexural, impact strength, toughness. Length of use after the product does not appear covers crushed and damaged the phenomenon, to eradicate the "urban black hole" accidents. 
 (B) the appearance of the United States: Check covers the surface pattern is designed to beautify the urban environment. 
 (C) easy to use, light weight: the weight is only about one-third of the cast iron, easy to transport, install, repair, greatly reducing the labor intensity. 
 (D) security: the composite-plastic composite materials recovery value, and natural anti-theft; based on customer needs and has a locking mechanism to achieve the well property theft. 
 (E) weathering: the selection of molecular weight, chemical stability, high molecular weight materials as raw material, scientific formulas, advanced technology, perfect equipment to make the product in -50 ° C - +120 ° C normal to use. 
 (F) Low noise: the application of synthetic materials, special locking mechanism design, completely solve the noise problems caused manhole covers to the city. 
 (VII) acid, corrosion-resistant. 
 Polymer composites covers the carrying capacity 
 Light: fracture load 30KN to 50KN applies to the sidewalk green belt 
 General types: crack load 100KN to is 150KN apply to ordinary urban roads 
 Heavy: crack load 200KN to 300KN applicable to high-grade motor vehicle lanes