Classifying – separating – and assorting solids – Sifting – With liquid treatment
Patent
1986-07-30
1989-05-23
Basinger, Sherman D.
Classifying, separating, and assorting solids
Sifting
With liquid treatment
209306, 209397, B07B 120
Patent
active
048328324
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE ART
The present invention relates to a pressure type slit screen for removing coarse fibers, bound materials and other foreign matter mixed in paper material. The present invention can be applied to a centrifugal screen, a centrifugal sorter, a barrier screen and the like.
BACKGROUND OF THE INVENTION
A pressure type slit screen well known in the prior art is provided with a screen cylinder 1 having elongated slit-like openings as shown in FIGS. 35 and 36. Paper material supplied by means of a pump flows in through an inlet section 2, advances to a flow passage 4 surrounding an outer circumference formed by an inside casing 3, and heavy foreign matter such as metal pieces, sand and the like in the paper material is discharged outside of the system through a trap 5 provided in a tangential direction opposite to the inlet section 2. Paper material circulating through the flow passage 4 enters into an annular screening chamber 7 formed of the screen cylinder 1 and a bearing cylinder 6 from its top portion in the direction shown by arrow 8, then it is selectively filtered while passing through the screen cylinder 1 in the process of flowing downwards, and it is discharged through an outlet section 9.
On the other hand, foreign matter such as plastics, bound fibers, wood pieces, etc. having a size unable to pass through the screen cylinder 1, would flow down by themselves through the screening chamber 7, and would be discharged through a reject outlet section 10. In addition, hydrofoil members 12 (FIGS. 42 and 43) suspended from a top of a main shaft 11 and driven by an electric motor 13 revolve continuously at a high speed along the surface of the screen cylinder to stir the paper material and remove unpassable foreign matter on the screen cylinder surface, whereby they serve to always keep the screen cylinder clean, and at the same time they disintegrate fiber flocks produced as a result of mutual aggregation of fibers by strongly stirring and promote the flow of fibers passing through the screen cylinder.
Also in FIGS. 38 and 39, to the opposite ends of the cylindrical screen cylinder 1 are mounted taper rings 15 for equipping it in a main body of a screen apparatus, by means of taper pins 16. The screen cylinder 1 is provided with circumferentially extending rows of a large number of slit openings 19 each of which extends parallel to the rotational axis of the screen cylinder. On a surface 17 of the screen facing the screening chamber 7 are provided slit openings 19 which are straight in the direction of thickness of the screen cylinder and formed by walls which are separated from each other by a preliminarily defined dimension and which are parallel to each other, and inlet corner sections 21 where the surface of the screen cylinder and the parallel walls intersect nearly at right angles.
On a rear surface 18 of the screen cylinder 1 are provided escape grooves 20 having a sufficiently large opening dimension as compared to the slit opening 19. FIG. 42 shows a structure of a screen cleaning device in the prior art, in which the hydrofoil members 12 are assembled by means of a spider 22 and a reinforcement ring 23 and they are mounted to move along a circular path across the surface of the screen cylinder.
However, in order to obtain predetermined stirring and cleaning effects based on the principle of the hydrofoil, it is necessary to extremely narrow the gap clearance between the hydrofoil member 12 and the screen cylinder to as small as 1.5-2.5 mm and to drive the hydrofoil members at a high speed of 10 m/sec. to 30 m/sec. To that end, additional support members and reinforcement members are necessitated for the purpose of assuring a rigidity for withstanding the high-speed rotation, and upon assembly also, a high degree of technique is required. Such support members and reinforcement members had various shortcomings such that since they form surface portions which cause adhesion and binding of fibers in paper material, and since they result in large power loss, counter-measures against p
REFERENCES:
patent: 3363759 (1968-01-01), Clarke-Pounder
patent: 3483974 (1969-12-01), Pearsall
patent: 4276159 (1981-06-01), Lehman
patent: 4318805 (1982-03-01), Le Blanc
patent: 4356085 (1982-10-01), Schon et al.
Fujiwara Haruyoshi
Katsube Ryojiro
Basinger Sherman D.
Mitsubishi Jukogyo Kabushiki Kaisha
Swinehart Edwin L.
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