feeding device which is connected by four conveying conduits 2 to a flow splitter device 3 the flow splitter device 3 is pneumatically fed with material and transport gas through conveying conduit 4 which is connected to a rotary valve material feeding device 5 a conveying gas blower or compressor 6 provides the conveying gas material for conveying is stored in feed hopper 7 bulk material is fed into vessel 1 tangentially in such a way as to cause the material in the device to rotate at sufficient speed to ensure the rotating mass of material 8 is forced against the walls of the device 9 within the device the level of bulk material builds up until it flows down an exit pipe 10 as a smooth thin concentrated hollow sleeve 11 the exit pipe 10 is of smaller diameter than the main body 12 of vessel 1 but is nonetheless of substantial diameter compared with that of the main body of the vessel transport gas 13 flows out of the device in the centre of the sleeve 11 referring to fig2 a and 2 b there is illustrated one form of vessel 1 for use with the system described above the vessel is of generally cylindrical shape having a closed end 1 a a main body portion 1 b from which extends a narrowing frusto conical portion 1 c terminating in an outlet 10 having a diameter roughly half that of the main body portion 1 b main body portion 1 b is provided with four circumferentially and equally spaced apart tangential inlets 14 in use each inlet will be fed with an approximately equal amount of material and gas for entry into the.