GB768558A - Improvements in or relating to recovery and classification of solids - Google Patents

Abstract

768,558. Pneumatic separating. PHILLIPS PETROLEUM CO. Feb. 9, 1954 [Feb. 16, 1953], No. 3771/54. Class 117. [Also in Groups XXVIII and XXXVII] Suction is applied to spilled carbon black mixed with grit particles to suspend the mixture in a gaseous stream which is introduced into the upper region of an elongated upright vessel, into the lower portion of which extends an air line, the rate of flow of the two streams being arranged so that the grit particles settle to the bottom of the vessel where they are withdrawn, while gas containing suspended carbon black is withdrawn from the top of the vessel and fed to a separator. As shown, the blower 12, Fig. 1, draws air, carbon black and grit through conduit 10, to be pulverized in a blower 19, an adjustable proportion of the output of which is re-cycled therethrough via valved line 22. The main stream passes through line 23 radially into the top of a settling vessel 24 comprising an upper cylindrical part 25 and a frusto-conical lower section 26, closed by a star valve 30. A frusto-conical plate 27 having an opening 27h, protrudes downwardly into the lower section and an adjustable amount of air from pipe 28 is admitted into the annular space between plate 27 and the wall of section 26 from the tangential inlet 29. The heavier grit particles and some of the carbon black fall through valve 30 to be entrained in air from pipe 35 and carried via pipe 36 to a second similar separator 24a, while the bulk of the carbon black passes up through a duct 32, which protrudes into the top of the section 25, and conduits 33, 40 to a cyclone separator 41. The grit outlet valve 30a of the second separator 24a is connected to a hopper 38, the carbon black outlet 32a being connected to the cyclone separator 41. The outlet valve 42 of the latter feeds a conveyer 44 for the recovered carbon black. Any residual solids in the air outlet 46 of the cyclone 41 are recovered by a bag filter 47, the air outlet 48 of which is connected to the suction of blower 12 while the black recovered is fed through star valves 49, 49a, to the conveyer 44, when the loose black on the filter cloth is released by the operation of two shaker motors one of which 51, is shown. The blower 12 operates continuously, until the pressure differential across the unit 47 is greater than a predetermined value, when the blower motor is de-energized for a timed period, during which the shaker motors are operated. At the end of the period normal operation is resumed unless the pressure differential is still too high, when another cycle of shaker motor operations is initiated. This operation depends upon the position of an air-operated switch 57 controlled by a unit 54 fed over lines 52, 53 from the inlet and outlet conduits 46, 48 of the bag filter 47. The motor control circuit comprises the switch 57, Fig. 2, which normally completes the circuit of the operating coil 64 of the contactor 60 controlling the main blower motor 13, and the circuit of the coil 66b in the timer unit 66 to keep open contacts 66a, 66d. When switch 57 opens, contactor 60 is de-energized to disconnect motor 13. Coil 66b is de-energized, to close contact 66d to energize the timing motor 66c, and to close contact 66a to energize the operating coils of contactors 61, 62, switching on shaker motors 51, 51a. At the same time the operating circuit of contactor 60 is broken at contacts 61a, 62a. At the end of the timing period contacts 66a, 66d momentarily open to switch off contactors 61, 62 and restore the operating circuit of contactor 60 and coil 66b if switch 57 has now closed. If however, switch 57 is still open, a further timed period of operation of motors 51, 51a, recommences. The equipment is primarily applicable to the recovery of carbon black spilled in an area over which the conduit 10 extends. The conduit is provided with fittings 11, Figs. 1, 3, to which a hose 78 and pick-up device 84 may be secured. Each fitting comprises a seat 74, with a tapered inner surface 75, normally closed by a pivoted cap 76 and gasket 77. The hose 78 has a screw-on tapered fitting 79 which may be secured to the inlet when cap 76 is raised.