GB898316A - Apparatus for keeping clean the inner wall of atomizing driers - Google Patents

Abstract

<PICT:0898316/III/1> <PICT:0898316/III/2> In a spray drier for drying solutions of solids, such as milk, the inner wall of the drier is kept free from deposits of solid particles by jets of gas such as air discharged from nozzles moving with slight clearance along the inner wall, the nozzles being assembled in two or more groups which are alternately connected to a source of compressed gas so as to blast jets of gas against separate sections of the inner wall in succession. In the drier shown in Fig. 1, the jets emerge from tubes 12 and 13 which branch off the upper end of rotatable tube 11, mounted within fixed tube 9. Tube 13 is fitted with nozzles along its entire length, whereas tube 12 only has nozzles in its upper vertical part. Tube 11 is rotated about its axis by toothed gears 17, 18 driven by motor 16. Compressed gas from source 10 is conveyed to tube 9 via flange 21 (Fig. 2), and passes into tube 11 via slots 27. Tubes 12 and 13 are alternately supplied with compressed gas by means of switchover device 14 which consists of two pistons 28, 29 fixed on rod 24, the piston 29 having bores 30. The pistons are fixed on rod 24 which is moved up and down by change-over gear 15. As the rod ascends and descends the pistons alternately open and close the apertures leading to tubes 12 and 13 so that one aperture is open while the other is closed; and the compressed gas blasts out of the jets from one or other of the tubes in turn against the cylindrical section or the conical section of the inner wall of the drier. A form of construction with four successively operating blast tubes is also described. The drying of tea, coffee, blood and soap is mentioned.