Patent GB-900735-A (GB)
Title: Apparatus for feeding pulverulent material
Inventor: TOLMAN EDGAR B
IPC: B65G53/46
Filed: 1960-08-04
Abstract: 900,735. Pneumatic conveyers. UNITED CONVEYOR CORPORATION. Aug. 4, 1960, No. 27055/60. Class 78 (1). Ash from a coal-burning boiler (not shown) is fed from a hopper 19 to a pneumatic conveyer duct 66 by a device 11 comprising a chamber A having a porous aerating base 29 and leading via a valve-controlled orifice 26 to an airlock chamber B. The latter has an aerating porous base 34 and its exit is controlled bv an orifice 31 and valve 38. Each valve 38, 38a, is controlled by a pneumatically-actuated diaphragm 45 against spring loading 46 tending to maintain the valve in closed position. A vent 55 leads from the chamber B and is connected via a filter (Fig. 1a, not shown). Two of the devices 11 are shown at 11a, 11b in Fig. 2, with their outlet chambers C connected to a common duct of a pneumatic conveyer having a blower 62. A conduit 67 on the high-pressure side of a pressure-reducing restriction 65 in the duct 66 supplies air necessary for operating the diaphragms 45, of the valves 38, and 38a, and for conduits 52, 54 connected to the spaces 53, 53a, beneath the porous fluidizing bases 51, 51a. The air supply to the spaces 53, 53a beneath the fluidizing beds 51, 51a. A further compressed-air source (not shown) is connected by a conduit 71 to provide a highpressure line 75 (broken lines) and by means of pressure-reducing valves 77, 79, a low-pressure  line 78 (dot-dash lines). For the position of the device as shown in Fig. 1, with the valve 38a open and the valve 38 closed, the line 78 is connected by a solenoid-operated valve 88 to a line 89 connected to the diaphragm 45 (f each of the devices 11a, 11b. The line 78 is also connected to a further solenoid-operated valve 96. The solenoids of the valves 88, 96, are actuated in timed relationship by cam-actuated contacts so that when valve 88 is open to diaphragm 45 of valve 38a as shown, valve 96 is closed to a line 97 leading through a valve 98 to the diaphragm 45 of the valve 38 of each device 11a, 11b. The valve 98 is normally open but is solenoid operated to block the line 97 when a pressure-operated switch 85 connected to the conduit 67 is actuated by the effect of a blockage in the conveyer duct 66. The valve 96 is also connected to the high-pressure line 75. In the position shown, the high pressure line 75 is connected to pneumatically-operated valves 106, 108a and 108b. The valve 106 in the position shown is held so that it breaks a connection between the conduit 67 and a conduit 54 leading to the chamber 53a beneath the fluidizing base 51a. The valve 88 similarly controls the supply from highpressure line 75 to pneumatically-operated valve 86, 87a and 87b. In the position of the valve 88 shown, the valve 86 is set to connect the conduit 67 and the space 53 beneath the fluidizing bed 51. The valve 108a controls the connection between a reservoir 68a connected to the conduit 67 and a conduit 60a connected to a vent 55a leading from the chamber B. The valve 87a controls the connection between the vent 55 and atmosphere. Thus in the position shown, the vent 55 is cut-off from the reservoir 68a and is connected to atmosphere. At the point in the cycle when the valves 88 and 96 are in opposite phase from that shown, the vent 55 is supplied with high-pressure air from the reservoir 68a. A filter (Fig. 1A, not shown) is disposed in the vent 55. Conduits are provided in Fig. 2 to supply a pair of additional units 11a, 11b, which may be connected so as to operate in opposite phase from those shown. The blower 62 may alternatively be used to suck air through the apparatus.