To provide a reducer for invert matching, formed of an earthenware pipe and easily joining two earthenware pipes of different bore diameters without causing inverse draft and without causing a large gap.
The reducer 21 for invert matching comprising the single earthenware pipe which is formed by joining two earthenware pipes 24, 25 of different bore diameters in the same axis direction while matching the inverts and by filling a gap between mutual joined parts of the two earthenware pipes 24, 25 is provided. When manufacturing the reducer 21 for invert matching, the two earthenware pipes 24, 25 are joined by: forming cutout portions in joining side ends of the large diameter earthenware pipe 24 and the small diameter earthenware pipe 25, respectively; while matching the inverts of the large diameter earthenware pipe 24 and the small diameter earthenware pipe 25 to each other, butting the joining side end of the small diameter earthenware pipe 25, which is not cut, against a cut face in an axial direction of the cutout portion of the large diameter earthenware pipe 24; inserting the cutout portion of the small diameter earthenware pipe 25 in the large diameter earthenware pipe 24; laying the vicinity of the cutout portion of the small diameter earthenware pipe 25 on the inside of the large diameter earthenware pipe 24; and filling the gap between the mutual joined parts of the two earthenware pipes 24, 25.
YOSHIDA KINJI
TATEWAKI YOMIO
FUJITA KAZUMI
HAYASAKA TERUO
KITADA KATSUMASA
Yasuo Kawanari
Noriko Kawai
Ikuo Kobayashi