Pig cleaning methods for water pipes have attracted attention because they are more effective in cleaning than conventional methods, but the hydraulic characteristics of the permeable spherical u rethane pigs themselves have not been fully elucidated. Therefore, in order to understand the basic hydraulic characteristics of pigs, e xperiments were conducted at an outdoor test site , and the pressure fluctuations in the pipe and velocity during pig flow were analyzed respectively. The pressure in the pipe increased up to 14.5% as the diameter ratio of pig to pipe increased. But, in the range o f the dia meter ratio less than two used i n normal cleaning conditions, the pressure in the pipe was less than 10% of the average pressure in the pipe, and the effect on the pipe pressure resistance was small. The two types of pigs with different cleaning effects exhibited continuous flow associat ed with the water flow, and the velocity of each type was proportional to the water velocity. This study confirmed the safety of the pig cleaning and provided knowledge for improving control in actual on site operations.

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[in Japanese]

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