| 摘要 |
PROBLEM TO BE SOLVED: To drain water underground. SOLUTION: This draining device is provided with a cylindrical body 3 opposedly combining a lower ditch-like member 6a and an upper ditch-like member 6b of the same shape. The lower ditch-like member 6a and upper ditch like member 6b have protrusions 13 circumferentially formed along a side wall inner surface 9. The protrusions 13 are so formed that the center parts opposed to the open face are recessed into the position of the side wall inner surface 9, and a plurality of protrusions 13 are provided in the axial direction 4 of the upper and lower ditch-like members. A plurality of holes 11 are provided in the side walls 8 of the upper and lower ditch-like members 6a, 6b.
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