04182581 is referenced by 44 patents and cites 6 patents.

A pipe for underdrainage comprises (1) a liquid-collecting pipe; (2) a plurality of discontinuous protrusions on the outer surface of the liquid-collecting pipe; (3) a filter layer capable of passing liquid while substantially excluding solids, the filter layer being disposed around the liquid-collecting pipe and contacting the top portions of the protrusions; and (4) a liquid-conducting way composed of a space communicating both in the longitudinal direction and in the peripheral direction of the liquid collecting pipe and defined by the protrusions, the outer surface of the liquid-collecting pipe and the inner surface of the filter layer.

Title
Pipe for underdraining
Application Number
5/887608
Publication Number
4182581
Application Date
March 17, 1978
Publication Date
January 8, 1980
Inventor
Yoshihisa Kusumi
Urawa
JP
Noriyuki Ishii
Chiba
JP
Minoru Inaba
Chiba
JP
Yoshio Uehara
Kashiwa
JP
Agent
Cooper Dunham Clark Griffin & Moran
Assignee
Mitsui Petrochemical
JP
IPC
F16L 11/11
E02B 13/00
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