| 摘要 |
PURPOSE:To prevent the splashing of a coating material and to keep the health of operators by providing a funneled dust-collecting cover which surrounds a nozzle and whose leading end is opened, circulating again the coating material recovered by the cover to the nozzle flow passage side, and reusing the material. CONSTITUTION:When a coating material such as concrete and mortar is sprayed onto the inner wall surface of a tunnel which is dug through, a dust collecting cover 12 is unitedly equipped to the outer peripheral part of a nozzle 11, the base end part is welded to the peripheral wall of the nozzle 11 and closed, and the diameter of the leading end side is gradually increased to form an opened funnel. An opening 13 is provided to the peripheral surface of the nozzle 11 adjacent to the bottom part of the dust collecting cover 12, and the cover is communicated with the nozzle. The material is successively sucked into the nozzle 11, and sprayed again from the nozzle 11. Consequently, the dust of the coating material which is splashed during the spraying operation is interrupted, and the unfavorable effect on the health of operators can be controlled. |
