Blocking device e.g. valve box for water pipelines to cover and locate access well in roadway system to support passage of heavy vehicles, has cover made of plastic material armed with glass fiber with high mechanical resistance

摘要

The device has a body (3) embedded in ground. A removable closing manhole cover (4) is provided with a support flange (5) on a corresponding edge (6) of the body. The cover comprises an additional support unit (D) provided on a face opposite to a roadway system during withdrawal of the flange. The additional support unit cooperates with a combined support unit (A) in the body. The cover is made of plastic material i.e. polypropylene armed with glass fibers with high mechanical resistance.