| 摘要 |
360,357. Centrifugal machines ; ball or tube mills. HARDINGE CO., Inc., 122, East 42nd Street, New York, U.S.A.- (Assignees of Hardinge, H.; York, Pennsylvania, U.S.A.) July 24, 1930, No. 22366. Convention date, Aug. 31, 1929. [Classes 23 and 59.] The joints of a rotary, pulverizing mill of the type described in Specification 263,820, [Class 23, Centrifugal machines &c.], are surrounded by chambers in which the pressure is reduced by means of a pump to below atmosphere and to below that in the mill, to prevent the escape of elastic fluid which is used for conveying the product from the mill. The air or other fluid is circulated continuously through the system by a blower 10 and passes from passage 12 through an annular, conical passage in the mill and returns through a conduit 13 to a classifier 15 and thence by passage 16 to a dust collector 17. The air returns through a conduit 18 to the blower 10. The pressure is controlled by a vent 19 and a butterfly valve 20. The material of undesired coarseness drops to part 21 of the classifier and is returned for further pulverization, as is also the contents of the cone 23. An annular box 28 is arranged around the rotary joint 31 of the mill and air is evacuated therefrom through a conduit 29 leading to conduit 13. The pressure in box 28 is less than that in the mill and atmospheric air enters at the.joint 31. In a modified application to a mill feeding coal to a furnace, Fig. 3, the discharge end of the mill is sealed by a chamber 38 connected by a conduit to the suction side of the blower 33. Sealing-means are also provided at the feed end of the mill. Coal passes from a bin to a hopper 44 and through a valve gate 46 to the mill. Chambers 48, 40 around the joints are connected to the suction pipe 42 or to a venturi restriction in the discharge pipe 37. In another application, the air goes through the mill from end to end. An annular box at the discharge end of the mill is connected to the blower suction. A bucket is connected to a flange on the mill and rotates in the box and carries around particles which leak through the joint to the top of the box from where they drop into the air withdrawn from the box and are returned to the mill. Similar joints may be used in rotary dryers using hot gases.
|
