Sewer or well shaft top compensating ring - comprises two concentric rib linking high melting temp. plastics rings

摘要

The intermediate layer is set between the top edge of a sewer or well shaft tube or displacement plate on top of this, with a cover frame holding a lid. The compensating ring disc is made of plastics. The disc (24) is made up from two concentric rings (25, 26), interconnected by a series of radial ribs (28). These are made of hard plastic, with a melting temp. higher than that of bitumen. The ribs are pref. trapezoid in cross-section and one or both sides of the disc may be roughened. The sides may enclose an acute angle in a diametral direction, to form two wedge faces of a wedge disc. This can be easily built in with effective sealing and can also be removed again without being destroyed.