| 摘要 |
PURPOSE:To detect easily a bullet which blocks a pipe when the pipe is washed, by inserting an internal magnet piece of the pipe washing elastic bullet and moving the pipe blocked with this bullet in the axial direction of the pipe and detecting the magnet piece with a magnetic sensor. CONSTITUTION:A pipe washing elastic bullet 7 is constituted by sealing up a permanent magnet 10. This elastic bullet is inserted from one end of a steel pipe 3 and is allowed to pass in the steel pipe 3 by the difference between gas pressures before and after the bullet, thereby washing the steel pipe 3. Though there are no problems when the bullet passes through the steel pipe from one end to the other, the bullet must be detected when the bullet is stopped on the way. Therefore, a magnetic sensor 23 is arranged on the way where the steel pipe 3 is pulled out from a winding body 2 and is wound around a bobbin 19. If the bullet exists in the steel pipe 3, a solenoid 22 of the magnetic sensor 23 detects the magnetic field of the permanent magnet in the bullet to generate a voltage. |
