| 摘要 |
<p>A manhole shaft that comprises at least two ring-shaped sleeves (20, 21, 22) mutually welded together. The ring shaped sleeves are designed with a number of ring-shaped waves (7), with each a crest (8) and a trough (9). The ring shaped sleeves have at least one prevent chamfer (23, 24), that extends across the waves (7) in at least one to at least one sleeve (20, 21, 22) belonging wave crest (8) and/or trough, where the prevent chamfers serve to prevent the shaft from moving and/or turning with mechanical or thermal weight. The sleeves are rotary moulded and gathered together with help of welded butt to butt to form a completely in and out trickle dense manhole shaft.</p> |
