Abstract: A shearing action of rubber by a rotor wing has a relation to a wing perpendicular component P.sub.z of P (see FIG. 4), and the larger the value of P.sub.z, the larger the shearing action. An agitating action of rubber has a relation to a wing parallel component P.sub.x of P (see FIG. 4), and the larger the value of P.sub.x, the larger the agitating action. In order to maintain the shearing action and the agitating action of rubber at a high level, in an internal rubber mixer a helix angle of a long wing 2 is set in a range of not less than 30.degree. and less than 50.degree.. Further, an axial directional length L.sub.s of a short wing 3 is made larger than that (.delta.) of a cut-off portion of the long wing 2. A rubber flow f-1 is thereby prevented from passing straight through a rotor space portion.

Abstract: Improvements are made in the known apparatus for collecting effluent oil of the type such that the apparatus includes a pair of left and right side plates disposed at a predetermined distance in a forwardly opened arrangement, a weir plate mounted to said side plates as inclined in a rear-downward direction so that its opposite side edges may contact with the inner wall surfaces of said respective side plates under a water surface, a slant plate disposed with its rear end positioned above the rear end of said weir plate at the rear ends of said side plates and having its opposite side edges fixedly secured to the inner wall surfaces of said side plates, an oil leakage preventing plate positioned in the midway between the rear end of said weir plate and the rear end of said slant plate and having its opposite side edges fixedly secured to the inner wall surfaces of said side plates to form a water discharge port between said oil leakage preventing plate and the rear end of said weir plate and to form an oily w