Patent GB-1160739-A (GB)
Title: Process and Device for Stemming Tobacco Leaves and Separating the Products Obtained
IPC: A24B5/10
Filed: 1966-11-01
Abstract: 1,160,739. Pneumatic separation. SERVICE D'EXPLOITATION INDUSTRIELLE DES TABACS ET DES ALLUMETTES. 1 Nov., 1966[3 Nov., 1965; 17 Nov., 1965; 26 Aug., 1966; 20 Sept., 1966], No. 48805/66 Heading B2H. [Also in Division A2] In an apparatus for stemming tobacco leaves and separating the products into light elements, i.e. fragments of parenchyma, and heavy elements, i.e. stripped stems, in which the leaves are fed into a beater rotating within a stemming chamber and the light and heavy elements are separated by an air stream, the air stream passes through the stemming chamber effecting partial separation of the elements therein, the heavy elements are discharged from an outlet distinct from the outlet or outlets provided for the air, and the air flows through the air inlet to the chamber in a direction opposite to the direction of discharge of the heavy elements. In one embodiment, Fig. 7, suction applied to the downstream end of the apparatus produces an air flow F that causes tobacco leaves, fed from a conveyer 101, to be drawn through a duct 102 into a main beater chamber. From this chamber the heavier elements pass through an opening 116 to a finishing beater beneath it and the lighter elements pass up into an expansion chamber 107 wherein further separation into light and heavy elements takes place, the heavier of these elements being returned via a rotary lock chamber 108 through an opening 115 into the main beater chamber for further stripping and separation. Further separation of incompletely stripped leaf stems is effected in expansion chambers 109, 110 from which they are returned, via lock chambers 113,114, to the conveyer 101 and hence to the main beater chamber for further processing. The stalk-free parenchyma fragments are centrifugally separated from the air passing to the suction source by a device 111 and are then discharged via a lock chamber 112. In another embodiment, Fig. 15, tobacco leaves are fed via a lock chamber 312 down a duct 311 and are distributed by an impeller covering the top of a rotating drum 301 into the topmost of three coaxial stemming chambers. These stemming chambers comprise beaters 308, 309, 310 fixed to the drum 301 within cylindrical cages formed by a plurality of vertical bar guides 303. Air is sucked through heavy element discharge apertures situated towards the outside edge of a circular base plate 305 and also through inlets 306 into the lowermost stemming chamber and passes successively upwards through the other chambers and to duct 317 leading to an expansion chamber 321 and thence via an opening 322 to a combined light element and air discharge outlet. Incompletely stripped stems fall within the expansion chamber 321 back into the beating chambers. Many other embodiments are disclosed and include apparatus comprising horizontal axis beaters used singly or in combination with either horizontal or vertical axis beaters, conically disposed beaters within conical shaped beating chambers, and cyclones for removing dust from the discharged air flow.