| 摘要 |
919,632. Drying apparatus. MARK, A. Feb. 17, 1959 [Feb. 20, 1958], No. 39474/62. Divided out of 919,631. Class 34 (2). In a pneumatic drier of the kind comprising one or more tubular vertical drying chambers inserted in a drying conduit to receive a gas stream carrying in the suspended state a divided material to be dried, the or each chamber having a lower axial inlet and an upper axial outlet, additional fresh hot drying gas is admitted tangentially into the or at least one of the said chambers at a point situated at a vertical distance from the said inlet at least equal to half the inner height of the chamber. The drier shown comprises drying chambers 28, 29, Fig. 3, of bi-conical shape disposed in vertical succession, the maximum diameter of the upper chamber being larger than that of the lower one. Moist material is fed into the chamber 28 in front of a jet of hot air issuing from a nozzle 4 from a hopper 13a through a screw-feeder 11, 12a. In the upper portion of each chamber additional fresh air from the generator 2 is introduced tangentially through inlets 10<SP>1</SP>, 10<SP>11</SP> such that the heaviest particles in the said portion are centrifugal against the conical wall thereof and tend to roll downwardly thereby increasing their time in the chamber. Balls 27 in the upper chamber 29 are " fluidized " by the rising air and thus form a vibrating screen preventing the heaviest particles rising directly into the upper portion of the chamber 29 without previously whirling in the lower portion thereof. The air stream is drawn through the drier by an exhaust blower 8 partial recirculation of the air occurring through a pipe 30 which connects the outlet of the blower with a nozzle 31 disposed coaxially in the nozzle 4. A blower may be provided between the generator 2 and the pipe 10. In the latter case the recirculating pipe and nozzle 31, 30 may be dispensed with. A further embodiment is described with reference to Figs. 1 and 2 (not shown) which is identical with that described in Specification 919,631. |
