To provide a non-interrupted stream cutting system capable of cutting off a part of an existing pipe without producing chips.
This non-interrupted stream cutting system is provided with a main body 10 of a cutting machine 1 fixed to the existing pipe 100, a cutting wheel 23 turning peripherally around the existing pipe 100 along two side faces in the direction of pipe axis in the main body 10 and rolling over, a retainer for holding each cutting wheel 23 to advance and retract in the radial direction of the existing pipe 100, a ring 20 for holding each retainer to rotate for the main body 10, a driving mechanism for turning each ring 20 peripherally around the existing pipe 100, and each feeding mechanism for letting the cutting wheel 23 advance toward the center of the existing pipe 100 in accordance with peripheral turn of each cutting wheel 23. All the cutting wheels 23 are provided in only a scope of substantially 180 around the existing pipe 100.
NAKAHARA OSAMU
YAMASHITA TAMOTSU
YOKOYAMA TAIHEI
SUIKEN KK
NIPPON STEEL PIPELINE CO LTD