| 摘要 |
PURPOSE: A spiral pipe is provided to improve the durability and firmness of a reinforcing support unit and both walls by integrating a reinforcing unit with both sides of the hollow units. CONSTITUTION: Hollow units(35,35') are formed at the upper and lower parts of a reinforcing support unit(31). A corrugated supporter(41') having a groove unit is connected to the center of the reinforcing support unit. The corrugated supporter is integrated with both sides of the hollow units.
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