Patent GB-660518-A (GB)
Title: Improvements relating to pressure-sealed conveyors for powdered material
IPC: B65G53/44
Filed: 1949-08-23
Abstract: 660,518. Conveyers. HAPMAN, H. W. Aug. 23, 1949. No. 21861/49. Class 78 (i). An apparatus for conveying and feeding powdered material under pressure, comprises a pressuretight conduit structure including pressure - tight supply and delivery containers connected to one another by conveyer conduits, an endless flight conveyer mounted in and traversing said containers and conduits, a pressure fluid supply source connected to said conduit structure for placing said structure under superatmospheric pressure, flight conveyer sealing devices mounted at the conveyer entrance and exit openings in said delivery container and having portions snugly engaging the peripheries of the conveyer flights to prevent pressure fluid escaping from said container, a delivery conduit connected to said container. and a second pressure fluid supply source of higher pressure than said first-mentioned pressure fluid source connected to said delivery container for expelling through said delivery conduit the powdered material conveyed thereto by the flight conveyer. The figures show an embodiment in which powdered coal is fed from a hopper 11 by a flight conveyer 13 to a container 12 where it falls into the conduit 80 of a pneumatic conveyer by which it is discharged into a boiler firebox or a gas turbine combustion chamber. The conveyer driving sprocket 14 is supported in a housing 20 and driven by a motor 27 through a gear box 25 and belt-and-pulley gearing 22, 23. The idler sprocket 15 is supported in a housing 37 on a member 32 which is slidable on a platform 34 whereby the tension of the conveyer chain may be adjusted. This adjustment is made by rotating a nut 36 engaging a screw 35 secured to the bearings 19 of the sprocket shaft 17. Sealing devices 49, 50 forming part of the conveyer conduit maintain the latter in a fluid-tight condition. They each comprise a tubular casing 64 of rubber or synthetic rubber provided with an inflatable chamber 66 connected by a pipe 67 to a pressure fluid supply. When the chamber is inflated, its inner wall 65 moves inward so as to hug the conveyer flights 60 as they pass to or from the container 12. Where the conveyer passes the container 12 it is supported by a pipe section 83 formed with a discharge opening 84 which widens in the direction of travel of the conveyer and which co-operates with a similarly shaped opening 85 in a sleeve 86 which is rotatably mounted on the pipe section and adapted to be locked in any position by a screw 87 so as to vary the discharge opening resulting from the alignment or mis-alignment of the openings 84, 85. When the container 11 has been filled and its cover plate 70 secured, a valve 72 is opened to connect a compressed air supply pipe 71 to pipes 73, 74, 75 and thereby fill the containers 11, 20, 37 and the entire conveyer conduit with compressed air. The motor 27 is then started to set the conveyer in motion and feed coal to the openings 84, 85 whence it falls to the conduit 80 to be delivered through a nozzle thereon to a boiler fire box or the like, the pressure in the conduit 80 being greater than that in the pipe 71.