Abstract: The invention relates to an existing pipe cut-off method and slitting method, by which an existing pipe made of cast iron and steel can be cut off. With a cut-off method according to the invention, first, a part of an existing pipe 1 is enclosed and sealed up by a seal-up housing 2 in an airtight state, a cutting tool 30 having a plurality of blades 30c is accommodated in the corresponding seal-up housing in a state the cutting tool is attached to the abovementioned seal-up housing 2. Next, the cutting tool 30 is fed toward the center of the abovementioned existing pipe 1 while slitting the existing pipe 1 by rotating the cutting tool 30 by power of a prime mover, and the abovementioned existing pipe 1 is cut off by the cutting tool 30 by turning the abovementioned seal-up housing 2 in the circumferential direction R of the existing pipe 1.

Abstract: The invention relates to an existing pipe cut-off method and slitting method, by which an existing pipe made of cast iron and steel can be cut off. With a cut-off method according to the invention, first, a part of an existing pipe 1 is enclosed and sealed up by a seal-up housing 2 in an airtight state, a cutting tool 30 having a plurality of blades 30c is accommodated in the corresponding seal-up housing in a state the cutting tool is attached to the abovementioned seal-up housing 2. Next, the cutting tool 30 is fed toward the center of the abovementioned existing pipe 1 while slitting the existing pipe 1 by rotating the cutting tool 30 by power of a prime mover, and the abovementioned existing pipe 1 is cut off by the cutting tool 30 by turning the abovementioned seal-up housing 2 in the circumferential direction R of the existing pipe 1.

Abstract: A pipe coupling arrangement for coupling an end of a pipe section includes a coupling body having its open end, into which the end of the pipe section is inserted. An outer ring and a radially compressed inner ring are disposed in the open end of the coupling body. Inclined peripheries are respectively defined in the inner periphery of the outer ring and the outer periphery of the inner ring. These inclined peripheries are inclined so as to become smaller in diameter as they advances towards the open end of the coupling body. The inclined periphery of the outer ring and that of the inner ring are engaged by each other. A pressing means for pressing an outer periphery of the outer ring is provided such that the inner ring is tightly pressed against an outer periphery of the pipe section via the outer ring. A space is defined by the inclined surface of the outer ring and the outer periphery of the pipe section, into which the inner ring is inserted.