Piping structure and process and pipe construction method

A process for forming an opening in a pipe 1, comprising:

• a step of attaching a rotating unit 2 around the pipe 1, the rotating unit 2 being rotatable in a circumferential direction R of the pipe 1, wherein a cutter 32 having a milling-shaped cutting tool 3 is attached to the rotating unit;
• a skin formation step of revolving the cutting tool 3 in the circumferential direction R of the pipe 1 together with the rotating unit 2 while rotating the milling-shaped cutting tool 3 about a central axis 30 of the tool, thereby cutting an outer surface 13 of the pipe 1 to form a groove G on the pipe 1, the groove G being elongated in the circumferential direction R and having a bottom that is formed as a skin 1S;
• a removal step of removing shavings T produced from the cutting;
• and
• a step of thrusting through the skin 1S to form the opening 10, after performing the skin formation step and the removal step.

A pipe construction method for obtaining a piping structure, the piping structure including a gate valve body 4 assembled into a pipe 1, the piping structure comprising:

• a pipe 1 that defines a groove G extending in a circumferential direction R, the groove G having a bottom that is formed as a skin 1S;
• a case 20 that encloses a portion of the pipe 1 including the groove G having the bottom;
• a gate valve body 4 that is arranged in the case 20;
• and
• a valve rod 43 that brings the gate valve body 4 closer toward the groove G and further moves the gate valve body 4 so as to thrust through the skin 1S of the bottom of the groove G to form an opening 10,
• wherein the gate valve body 4 includes:
• a circular-shaped valve main body 40 that enters an inside of the pipe 1;
• a blade 41 that is provided on a distal end side of the valve main body 40 for breaking the skin 1S to form the opening 10;
• and
• a seal portion 42 that is provided on a proximal end side, which is opposite to the distal end side, and contacts a portion of the pipe 1 around the opening 10 to shut the opening 10,
• the pipe construction method comprising:
• a step of attaching a rotating unit 2 around the pipe 1, the rotating unit 2 being rotatable in the circumferential direction R of the pipe 1, wherein a cutter 32 having a milling-shaped cutting tool 3 is attached to the rotating unit;
• a skin formation step of revolving the cutting tool 3 in a circumferential direction R of the pipe 1 together with the rotating unit while rotating the milling-shaped cutting tool 3 about a central axis 30 of the tool, thereby cutting an outer surface 13 of the pipe 1 to form the groove G on the pipe 1, the groove G being elongated in the circumferential direction R and having the bottom that is formed as the skin 1S;
• a removal step of removing shavings T produced from the cutting;
• a step of removing the rotating unit and the cutter 32 from the pipe 1;
• and
• a step of attaching the case 20 accommodating the gate valve body 4 therein to the pipe 1 so that the case 20 encloses the portion of the pipe 1 including the groove G having the bottom.