| 摘要 |
PURPOSE: A half-moon rotary manhole is provided to regulate the height rapidly without re-construction, to make mass production possible and to install rapidly in a concrete hole without an anchor bolt. CONSTITUTION: The half-moon rotary manhole is composed of an upper pipe, a lower pipe and a cover, wherein the height of a manhole is fixed and raised or lowered by attaching a half-moon rotary height regulating plate to the inside of the fixed lower pipe and engaging a half-moon rotary height regulating plate projected to the outside of the upper pipe.
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