GB1505166A - Air cleaner - Google Patents

Abstract

1505166 Multi-stage centrifugal separator DONALDSON CO Inc 20 May 1975 [20 May 1974] 21638/75 Heading B2P A gas from which particulate matter is to be removed is drawn into an elongate container such that it is caused to flow vortically in one axial direction with respect to an outer annular wall of the container and it is then constrained to be drawn through a labyrinth provided by passageways between concentric annular walls whereby the gas continues its vortical flow radially inwardly to a central passageway of the container, the particulate matter being caused to impinge on the successive annular walls by the centrifugal force to which the gas is subjected as a result of its vortical flow, the gas flow in adjacent passageways being in opposite axial directions, the innermost pair of annular walls having a helical partition arranged in the passageway extending between the walls such that the vortex energy of the gas is reinforced, and cleaned gas being withdrawn from the container through the central passageway. As shown in Figs. 2 and 4, a two-stage separator comprises a plurality of coaxial cylinders 10, 11, 12, 13. Gas laden with particulate matter is drawn, by means of a pump or blower connected to the outlet 25 of the cylinder 13, from a riser 70 and through a tangential inlet 14 into the outer cylinder 10 which at the top has a closure defining a helical surface 16 which directs the gas downwardly. After reversal and separation of heavier particulate matter, the gas passes upwards between cylinders 11 and 12 into a plenum chamber 72 where it reverses to pass between cylinders 12 and 13 where its vortical motion is increased by a helical blade 26. After reversal and separation of the lighter particulate matter, cleaned gas is drawn out of the separator through the cylinder 13. The angular relation, about the axis of the separator, between the leading edge 73, Fig. 4, of helical blade 26 and the point of tangency 74 of the inlet 14 with the cylinder 10 is is chosen to ensure that "feed back" vortex upstream of the blade does not oppose the input vortex but augments it. The separated lighter and heavier particulate matter are collected in inner and outer chambers 36 and 37 respectively of a hopper 30-33. A counterweighted, pivotable door 40 having a gasket 54 is used to close and open an aperture provided in the sloping bottom plate 35 of the hopper and serving to discharge particulate matter from chamber 36, the door being kept closed by the negative pressure in chamber 36 when the separator is in operation. A second pivotable door 60 made up of layers 64, 65, 66 of material of different stiffness is used to close and open an aperture provided at the bottom of the wall 32 of the hopper and serving to discharge the particulate matter from the chamber 37, the door during operation of the separator, being kept closed by the negative pressure which prevails in chamber 37 and in a channel 61, Figs. 2 and 8 which surrounds the aperture on three sides and is connected by a T-pipe 62 with chamber 36.