| 摘要 |
FIELD: hydraulic structures, particularly sewage systems to drain waste water, namely manhole closing means. ^ SUBSTANCE: hatch comprises body having upper and lower parts. Inner diameter of lower body part exceeds diameter of upper body part touching the lower body part. Upper body part is provided with flange having diameter related with upper body part diameter as df>1.25d, where df is outer flange diameter. Upper body part is spaced from lower body part to provide upper body part sliding with respect to lower body part in the case of road pavement displacement. Upper body part passes into lower body part and extends inside lower body part for distance related with upper body part height as 0.25h<s<0.5h, where s is above distance, h is upper body part height. ^ EFFECT: increased reliability of hatch retention in road pavement. ^ 3 cl, 4 dwg, 1 app |
