| 摘要 |
<p>1504625 Cleaning gas filter bags SVENSKA FLAKTFABRIKEN AB 1 May 1975 [2 May 1974] 18245/75 Heading BIT Gas filter bags (not shown) are cleaned by one or more pulses of reverse flow air delivered from a manifold 4, through nozzles 5 or apertures 7 directed towards the bag mouths, the inlet end of the manifold 9 being extended into a compressed air reservoir 1 where its free end presents an annular seat 12 which is normally engaged by a flexible diaphragm 11. The diaphragm is withdrawn for a short period by an electrically-actuated pilot valve 14, thereby delivering a pressure pulse into the bags whose duration is below 0.1 seconds and whose maximum pressure is reached in less than 0.030 seconds after the pulse begins, the rate of pressure increase being larger than in prior art constructions, thereby enhancing the cleaning effect with minimal use of air (Fig. 7, not shown). Diaphragm 11 may have apertures (Fig. 6 not shown) to reduce its return time. The reservoir volume should be 5 to 20 times that of manifold 4. In Fig. 9 (not shown) a plurality of manifolds are connected to one reservoir which is internally partitioned to achieve the latter requirement. Bags may be cleaned by a train of pulses (Fig. 8 not shown) created by supplying an electric square wave to valve 14.</p> |
