Abstract: A mixing and dissolving system includes a tank where a polymer flocculant in a solid state is mixed with water, a liquid feed unit for feeding an aqueous solution containing the mixed polymer flocculant from the tank, one regenerative mixer comprising a casing arranged at an intermediate position of a channel for the aqueous solution discharged from the liquid feed unit, and a bladed wheel where grooves are formed in a radial pattern on an outer circumference, and is used to mix and dissolve the polymer flocculant through pressure application by rotating the bladed wheel in the casing and forming a vortex flow of the aqueous solution along an inner circumferential wall of the casing, and an adjusting unit arranged at an intermediate position of a channel for the aqueous solution that has passed through the regenerative mixer, and controls pressure on a discharge side of the regenerative mixer.

Abstract: The present invention provide a polymer flocculant mixing and dissolving system and a method for mixing and dissolving a polymer flocculant that can produce a polymer flocculant solution in a short period of time using low power.

Abstract: Method and apparatus for cutting a pattern of a printed wiring board and for cleaning a printed wiring board wherein a laser beam is irradiated onto a printed wiring board to evaporate the irradiated portion. A suction nozzle for sweeping a surface region including the cut spot of the printed wiring board and for withdrawing molten matter adhering to the region, or a tape feeding apparatus by which an incombustible sheet or tape is disposed in close contact with the cutting spot of the pattern of the wiring board for collecting particles scattered during the pattern cutting is provided. Further, a laser beam is applied to a resin layer on an internal-layer pattern to expose the pattern, the width of the internal-layer pattern is determined, and the internal-layer pattern is cut in accordance with the determined width. Laser beams are applied to the printed wiring board obliquely from two directions to dry-clean the wiring board.

Abstract: Method and apparatus for cutting a pattern of a printed wiring board and method and apparatus for cleaning a printed wiring board are provided, wherein a laser beam is irradiated onto a printed wiring board to evaporate the irradiated portion, to thereby cut a pattern or clean the printed wiring board. A laser beam is irradiated onto a cutting spot of the pattern of the printed wiring board to volatilize and remove the cutting spot, and a laser beam having a lower energy density and a larger irradiation area than that used for the pattern cutting is applied to a region of the wiring board around the cut spot, to remove molten matter adhering to that region.