GB1424863A - Apparatus for collection of dirt particles - Google Patents

Abstract

1424863 Fluid filter H G G LYNFIELD (Aerodyne Development Corp) 23 Jan 1973 3454/73 Headings BID and BIT An air or liquid filter comprises at least one pair of concentric filter bags or sleeves 60, 64 through which fluid is filtered in series, the upstream bag 60 being periodically cleaned by delivering reverse flow fluid directly into the space between the bags which flexes said upstream bag. Fig. 9 shows a series of bag pairs arranged in rows in a common housing. Dirty air flows from inlet 65 to the interiors of open-ended inner bags 60 and dust is discharged at 68. Reverse flow blower 70 may draw air from filtrate outlet 79 or atmosphere and delivers it via respective solenoid valves 76 to manifolds defined between tube plates 58, 59, each manifold communicating with spaces between the bags of different rows. The filtration may proceed under suction at outlet 79 or delivery pressure at inlet 65, and in the latter case central part 57 of the housing could be omitted. In Figs. 1, 2 (not shown) construction is similar, but dirty air enters the apparatus via the dust hopper (10b), and the inner, upstream bag is closed at the top. The valve (31) controlling supply of reverse flow air is operated by a solenoid or ram. Fig. 3 (not shown) involves a similar filter bag arrangement, but a single reversible blower and two one-way valves draw filtered air from the outlet and deliver reverse flow air to between the bags. Several such bag arrangements could be located in one housing but with individual blowers, so that reverse flow air from one passes to others on forward flow. Figs. 6, 7, (not shown) illustrate pluralities of bag pairs in one housing enabling some pairs to filter while others are cleaned. In Fig. 7 filtration is under suction and reverse flow is created by opening valves (31) to atmosphere. In all above embodiments filtering flow is outwards and both bags are of flexible woven, felted or knitted fabric, but in Fig. 8 (not shown) flow is inwards and the downstream bag is of rigid ceramic, sintered metal or wire mesh and only the outer bag is flexible. In all cases the upstream or downstream bag may be the more pervious of the two, but preferably the upstream bag retains most of the dirt. Bags may be cylindrical or flattened. To prevent the inner bag collapsing completely during reverse flow, the two bags may be stitched together along seams 92 (Fig. 16) or the inner bag may be stitched to longitudinal metal rods or taut cords (Figs. 13, 14, not shown). Fig. 11 (not shown) illustrates an electric pulse-generating device which could improve bag-cleaning in any embodiment by repeatedly opening and closing a reverse flow valve or starting and stopping or reversing a reverse flow blower.