To suck scum in continually stable fixed state by notching the side wall of a suction pipe lower end part of the side, where the scum flows-in, to form a scum suction part.
A suction pipe 1 is upwardly extended at an obtuse angle of about 135- about 165° to the scum flowing-in direction. And the suction part 1a is provided at the lower part, where the scum flows-in, by notching a part of the lower end side surface of the suction pipe 1. The opening shape of the suction part 1a is optionally setted into a semicircular state or the like. An inverse triangular guide plate 1b is arranged inside of the gathering plate 2 in the lower end surface of the suction part 1a. The guide plate 1b is smaller than the gathering plate 2 and the upper side of the inverse triangle is downwardly inclined to form an inclined surface 1b'. As a result, the scum is sucked to the suction part 1a without being sedimented to be stably sucked into the suction pipe 1.
MASUDA TOMOYA
HATA TAKANORI
