Hisayoshi Kado

A Study on Air Jets for Sweeping Volcanic Ash on Lawn

A device for sweeping volcanic ash on lawn was designed and its capability has been tested. This lawn sweeper was installed above a conveyor belt on which artificial lawn was pasted. The ash was uniformly scattered on the lawn using a hopper, conveyed at a constant velocity to the lawn sweeper and swept by it. The lawn sweeper is composed of small air jets and an air flow in a channel above the lawn. The former lift up the volcanic ash from the lawn and the latter conveys it to the dust collector. In these experiments, the lawn velocity, i. e., scavenging speed, the velocity of air flow in the channel, the air jet velocity and the arrangement of the blow tubes are altered, and the rates of collection are examined. The effect of these conditions on the rates of collection, and the optimal conditions for a high rate of collection and uniform scavenging are clarified.

Dynamic Behavior of Brush Wheels for Scavenging Volcanic Ash.

The dynamic behavior of rotational brush wheels, which are a main part of a road sweeper scavenging volcanic ash, has been examined experimentally. The vibration of polypropylene brush fibers has been recorded by a video camera and it has been analyzed to elucidate the dynamic behavior of brush fibers relative to the length and thickness of the fiber, the revolution frequency of brush wheel and the scavenging speed. Consequently, it is revealed that certain combinations of the natural frequency and wheel angular velocity should be avoided, and that scavenging speed hardly affects the dynamic behavior of the brush fiber.