| 摘要 |
<p>PROBLEM TO BE SOLVED: To smoothly extrude a preceding pig stopped in a pipe by using a pig of a soft foam of which at least the rear flank is coated with a foam breaking paste as a pushing pig. SOLUTION: When the preceding pig 1 for removing the deposits, etc., in the pipe is stopped in the pipe by leakage of compression transporting fluid as a result of generation of a spacing between a deposited portion and the outer peripheral surface of the pig, the pushing pig 3 which is the soft foam of 0.02 to 0.06 g/cm3 in expansion density, is formed by coating at least the rear flank of the soft foam with the foam breaking paste 4 consisting of a non-pressure fluid permeable foaming resin having compressibility and flexibility equal to those of the soft foam at 0.05 to 0.8 mm and has a diameter greater than the diameter of the preceding pig 1 is inserted into the preceding pig to bring the outer peripheral surface and the deposits into tight contact with each other and the pig is made to travel by the compression transporting fluid, by which the preceding pig 1 stopped in the pipe is extruded.</p> |
