Patent GB-761914-A (GB)
Title: Improvements in or relating to apparatus for screening and comminuting
Filed: 1954-06-01
Abstract: 761,914. Strainers. INFILCO, Inc. June 1, 1954 [June 8, 1953], No. 16179/54. Class 46. [Also in Groups II and XXIV] Apparatus for screening solids from a stream of liquid, e.g. sewage or other liquid wastes, flowing in a channel 11 and comminuting them comprises a bar screen 16, a comminutor comprising a pair of rotatable rollers 20, 21 having projecting teeth which are arranged in different planes of rotation so that the teeth of one roller pass with clearance between the teeth of the other roller, the teeth on the rollers being arranged in rows non-parallel to the longitudinal axes of the rollers and to one another at the bite of the rollers, means for rotating the rollers about their longitudinal axes in the same direction and at different speeds, and reciprocatable rake members 61 extending between the bars 43 of the screen 16 and adapted to move material intercepted by the screen towards the bite between the rollers 20, 21. Hinged to a rod 45, Fig. 2, which forms the lower end of the screen 16, is a set of curved bars 44 to which are secured resilient plates 57, 58, the upper end of the plate 58 having prongs 59 interlacing with the bars 43 of the screen 16. A removable screen 50 is provided upstream of the comminutor and has a resilient plate 55 secured thereto. The plates 55, 57 and 58, which may be perforated; may instead of being resilient be hingedly supported and spring-loaded. The roller 21 is driven from a motor 26 through bevel gears 27, 28, Fig. 2, and the roller 20 is driven at a faster speed from the motor through worm and worm gear 29, 30, and a friction clutch 31 which is adapted to slip when the resistance to rotation of the roller 20 exceeds a predetermined value. The friction clutch is connected to an overload device, Fig. 8, comprising an overcurrent relay 32 which when energized by overcurrent closes a switch 33 to energize a solenoid 34 and move upwardly a plunger 35 connected to a clutch-operating lever 36 thus disengaging the clutch. When the overcurrent ceases, the switch 33 opens, the solenoid 34 is de-energized and the lever 36 is moved back into its clutch-engaging position by a spring 38. A time relay may be provided in the relay 32 to hold the switch 33 closed for a short period after overcurrent ceases. The rake members 61 are keyed to a shaft 63, Fig. 1, hingedly supported at its ends by arms 64 keyed to a shaft 65 which is reciprocated from a constantly rotating shaft 66 by means of an arm 67, connecting rod 68 and crank 69. Each arm 64 has a rearward projection 70 and the two outermost rake members each have a projection 71 which is hinged to a rod 72 urged upwardly by a spring 73 whose lower end abuts the projection 70 on the corresponding arm 64, the upward motion of each spring being limited by an adjustable looknut 74. The construction is such that the rake members reach the lowermost point of their travel before the crank 69 has completed its cycle of rotation and the rake members are held in that position for a predetermined period by a stop 75a which causes the springs 73 to be compressed. The stop may be constructed so that when the springs 73 are compressed, the rake members swing clockwise and upwardly. The screen 16 and rollers 20, 21 may be reversed in position as may the rollers 20, 21. The rollers may both be driven in a clockwise direction.