Patent GB-943352-A (GB)
Title: Apparatus for forming sheet material
IPC: A24B15/12
Filed: 1961-07-31
Abstract: 943,352. Reconstituted tobacco products. AMERICAN MACHINE & FOUNDRY CO. July 31, 1961 [Aug. 9, 1960], No. 27691/61. Heading A2C. [Also in Division D1] A self-sustainable sheet material, e.g. tobacco sheet, is formed on an endless moving belt by moistening the belt, applying dry, finely divided material to the belt, heating the belt, applying a liquid binder, applying a second layer of material and raising the moisture content of the dried layers by cooling the underside of the belt and impinging steam on the surface of the layers. General arrangement. The machine comprises an endless steel conveyer belt 20 running over rollers 22 and 24 (Fig. 1). A water applicator 30 deposits a film of water on the belt on to which a dust applicator 32 in turn deposits a layer of tobacco dust. The belt then passes under a drier 34 after which a layer of adhesive, prepared from tobacco stems, is applied by applicator 36. A further layer of tobacco dust is applied by applicator 38 and the tobacco sheet is then dried under drier 40, moistened in conditioner 42, and finally stripped from the belt 20. Water applicator. The water applicator 30 (Fig. 3) comprises a rubber roller 50 mounted in bearings secured to a vertically adjustable plate 56. The upper surface of the roller forms the bottom of a trough 86, the front of which is formed by an adjustable resiliently mounted skimming knife 72, and the back of which is formed by a rubber plate 84. The sides of the trough are formed by sealing plates 80 secured to the ends of the knife 72. Water is supplied to the trough 86 by a pipe 90. Dust applicator. The tobacco dust applicator 32, 38 (Fig. 1) consists of a closed hopper 104 (Fig. 6) in which runs an agitator 110, the bottom of the hopper being provided with an opening into which a knurled roller 116 projects. The roller is adjustably mounted in lugs 136 for movement towards and away from a rotating brush 138. To control the flow of tobacco dust between the roller 116 and brush 138 an adjustable gate 118 is provided. Troughs are provided under the edge of the belt 20 for collecting surplus dust. The troughs are vibrated and the dry dust is picked up by a suction funnel 156. The hopper 104 is provided with a vibrator 166 and a sensor 164 for detecting and controlling the level of dust. To prevent dampness a hot air pipe 168 extends through the housing. Drying. The drier 34, 40 (Fig. 8) which may be the same as that description in Specification 888,826, comprises a steam box 174 mounted under the belt 20 and supported on wheels 182 running on transverse tracks. A housing 172 is provided to which suction is applied by a fan 206 (Fig. 1). Lateral deviation of the belt 20 is detected by an arm 190 which controls an air cylinder 196 connected to the steam box support so that the steam box is moved on the tracks to follow the movement of the belt 20. Base web applicator. The applicator 36 (Fig. 9) for applying an adhesive prepared from tobacco stems to the belt 20 comprises a feed roller 210, a counter rotating refuse drum 212 and a rotary brush 214. The adhesive is applied between the roller 210 and drum 212 through a tube 272. The roller 210 is supported by bearing blocks 218 slidably mounted to track 220 so that the roller can be adjusted towards and away from the brush 214. The drum 212 is also supported by bearing blocks 250 slidably mounted in tracks 252 for adjustment relative to the roller 210. The tracks 252 are fastened to the blocks 218 so that the adjustment between roller 210 and drum 212 is not affected by adjustment of the roller 210 relative to the brush 214. Surplus material is collected by a trough 274. Sheet conditioner. The sheet conditioner unit 42 (Fig. 12) comprises a housing 288 within which is a cooling box 290 mounted on wheels running on transverse tracks 294. The cooling box is made to follow lateral movements of the belt 20 by a control device similar to that used in the drier 34. Within the cooling box are a plurality of transverse pipes 310 connected to a source of cold water, surplus water flowing out through a duct 314. The cold water is sprayed on to the underside of belt 20. Also in the housing 288, and above the formed tobacco sheet carried by the belt 20, are mounted a plurality of steam pipes 320 provided with jets 322 directed on to the sheet to raise the moisture content for subsequent processing of the sheet. Steam pipes 324 are provided adjacent the entrance and exit to the conditioner in order to evaporate any condensation on the tobacco sheet. Air is continuously sucked through the housing by a suction duct 326. Belt control. Lateral positioning of the belt 20 is controlled by an arm 336 (Fig. 1) which engages the edge of the belt 20. The arm 336 is connected to a transmitter 338 connected by a tube 340 (Fig. 14) to a source of compressed air. The transmitter is also connected to tube 342 which is connected to two air cylinders 344 and 348. The pistons 352 of the air cylinders have bearing blocks 354 which support the shaft 360 of a roller 362 which bears on the lower run of the belt conveyer 20. The arrangement is such that should the belt move to the right or left as viewed in Fig. 14, air is supplied to the right or left cylinder 348, 344 to move downwardly the right or left side. of roller 362, thus causing the belt to move back to its correct position.