To solve defects in suction type shot blasting.
This device removes oxidized scales on the inner surface of a steel pipe by a suction type shot blasting machine. In the case the inner diameter of a ground/polished/cleaned pipe 1 is D (m), the length of the pipe 1 is Lp (m), the average grain diameter of a grinding/polishing/cleaning material 11 is Dp (m), the specific gravity of the material 11 is d (kg/m3), the absolute value of negative pressure in a collecting box 3 for collecting the material 11 passing through the inside of the pipe 1 is Pr (Pa) and the atmospheric pressure is Pair (Pa), the depth length Lr (m) of the collecting box 3 satisfies Lr/Lp≥0.89 (0.13.Pr/Pair+268.63.Dp/Lp+9.85-D/Lp+0.012d)-0.105. The powdering rate of the grinding/polishing/cleaning material is lowered to suppress the cost of the grinding/polishing/cleaning material low, and the service life of the collecting box is lengthened to suppress maintenance cost low.
HORISAKA OSAMU
TANIDA MUTSUMI
HISHIDA YASUSHI
