US3145716A - Tobacco sheet forming apparatus - Google Patents

Description

Aug. 25, 1964 R. c. GElTZ ETAL TOBACCO SHEET FORMING APPARATUS '7 Sheets- Sheet 1 Filed Aug. 9, 1960 INVENTORS.

ROBERT CHARLES ean'z ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE ATTORNEY Aug. 25, 1964 Filed Aug. 9, 1960 7 Sheets-Sheet 2 1 P59 77 Fl 6.4 9D I I III l l 90 H: \gr.

' l 'IIIl/IIE' m4 88 82 I r- A 7 \02\E :V I J/ 2 INVENTORS.

ROBERT CHARLES GEITZ ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE L-/\ ATTORN EY Aug. 25, 1964 R. c. GEITZ ETAL TOBACCO SHEET FORMINGAPPARATUS '7 Sheets-Sheet 5 Filed Aug. 9, 1960 ENVEE' -LTORSL ROBERT CHARLES GEITZ ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE ATTORNEY Aug. 25, 1964 R. c. GElTZ ,ETAL

TOBACCO SHEET FORMING APPARATUS '7 Sheets-Sheet 4 Filed Aug. 9, 1960 FIG.7-

INVENTORS.

ROBERT CHARLES GEITZ ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE ATTORR EY.

Aug. 25, 1964 R. c. GEITZ ETAL TOBACCO SHEET FORMING APPARATUS 7 Sheets-Sheet 5 Filed Aug. 9, 1960 2 mm E s B E L m Wu C T R E B O R ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE ATTORN EY iE n INVENTORS.

ROBERT CHARLES GEITZ ALBERTO ISLAS 7 Sheets-Sheet 6 JOHN EDWARD LEE JOSEPH BRENDAN FARRELL R. C. GElTZ ETAL TOBACCO SHEET FORMING APPARATUS F l G Aug. 25, 1964 Filed Aug. 9, 1960 ATTORN EY Aug. 25, 1964 R. c. GEITZ ETAL 3,145,716

TOBACCO SHEET FORMING APPARATUS Filed Aug. 9, 1960 7 Sheets-Sheet 7 INVENTORS.

ROBERT CHARLES serrz ALBERTO ISLAS JOSEPH BRENDAN FARRELL JOHN EDWARD LEE FIG.

United States Patent 3,145,716 TDBACCO SHEET FOG APPARATUS Robert Charles Geitz, Darien, Conn., Alberto Islas,

Mexico City, Mexico, and Joseph Brendan Farrell,

Westport, and John Edward Lee, Byram, Conn.,

assignors to American Machine & Foundry Company,

a corporation of New Jersey Filed Aug. 9, 1960, Ser. No. 55,106 16 Claims. (Cl. 131133) This invention relates to an improved process and apparatus for forming a continuous self-sustainable web or sheet from particulated material. In a narrower aspect, this invention relates to tobacco sheet, and to apparatus and processes for forming tobacco sheet.

The broader applications of the invention which relate generally to the formation of a continuous web of material from finely particulated substances will become apparent in describing the invention hereinbelow. For the purpose of providing in greater detail the advantages afforded hereby, however, the invention will be described in connection with the preparation of a self-supporting tobacco sheet prepared from finely divided tobacco or tobacco dust. The useful application of the apparatus and process forming the basis of the present invention to the formation of continuous sheeting from other finely particulated material such as wood, leather, abrasive particles, flour or other edible foodstuffs and the like with desirable obvious modifications will be apparent to those skilled in the art.

An object of the present invention is to provide a very substantially improved method and apparatus for the continuous formation of flexible self-supporting web from particulated or finely subdivided materials in which the flavor, aroma, color or other desired characteristics of the material are retained.

A further object of this invention is to provide an apparatus which forms tobacco sheet of greater uniformity in thickness and more accurately controlled moisture content.

Another object of this invention is to provide an applicator to apply binding material in tobacco sheet formation in a fluid or slurry form with a more uniform distribution.

Still another object of this invention is to provide an applicator to apply binding material which is self-cleaning and non-clogging.

Yet another object of this invention is to provide, in an apparatus for the production of tobacco sheet, an endless steel belt extending about two large pulleys with apparatus to automatically correct for lateral travel or wandering of the belt on the pulleys.

A further object of this invention is to provide, in apparatus for forming tobacco sheet having an endless steel belt, drying apparatus and tobacco sheet conditioning apparatus which will automatically track or move with the belt to compensate for lateral wandering of the belt.

A still further object of this invention is to provide apparatus for the more even distribution of dry dust in the formation of tobacco sheet.

An additional object of this invention is to provide in a complete unit, a more compact machine for the production of sheet tobacco.

Many other objects, advantages and features of invention reside in the particular construction, combination and arrangement of parts involved in the embodiment of the invention and its practice as will be understood from the following description and accompanying drawing where- FIG. 1 is an isometric illustration of the entire assembly of the various components making up the sheet forming plant;

FIG. 2 is a front elevation of the water applicator;

FIG. 3 is a section taken on line 33 of FIG. 2;

FIG. 4 is a view, partially in section, taken on line 44 of FIG. 3;

FIG. 5 is a front elevation of the dust feeding and applying apparatus;

FIG. 6 is a side view, partly in section, of the dust feeding and applying apparatus;

FIGS. 7 and 8 are front elevations of the steam box drying apparatus with .the belt tracking mechanism;

FIG. 9 is a side elevation of the base web applicator;

FIG. 10 is an end view of the major base web applicator components;

FIG. 11 is a front view of the sheet conditioner;

FIG. 12 is a side elevation, partly in section, of the sheet conditioner;

FIGS. 13 and 14 are schematic front elevations of the continuous automatic belt tracking system;

FIG. 15 is a side elevation of the support and guide structure of the correcting roller of the belt tracking sys tem; and

FIG. 16 is a view taken on line 16-16 of FIG. 15.

Referring to the drawings in detail, the sheet forming plant illustrated in FIG. 1 consists of an endless stainless steel belt or conveyor 20 which is supported and driven at a constant speed by means of a pair of pulleys or drums 22 and 24 mounted on shafts 26 and 28 respectively. The belt 20 may be from 8 to 86 inches wide and, generally, from .016 to .050 inch thick and may be of half-hard, Type 301 Stainless Steel. The diameter of pulleys 22 and 24 should be at least one thousand times the thickness of belt 20. Shafts 26 and 28 are supported by suitable adjustable bearings of a main frame (not shown) of the machine. At the front and above the belt conveyor 20 is mounted a water applicator 30 which deposits a film of water on the top surface of conveyor belt 20. Also above the conveyor belt 20 a short distance from the water applicator 30, there is mounted a dust feeder 32 for the purpose of laying a layer of dust onto the film of water carried by the moving conveyor belt 20. After the layer of dust is applied on the film of water, the belt conveyor 20 passes through a suitable dryer 34 and then, upon emerging, passes beneath a base web applicator 36 which deposits a layer of suitable binder material onto the dried sheet material carried by the conveyor belt. After the binder material has been deposited onto the sheet, the belt conveyor passes beneath a second dust feeder 38 where another layer of dust is applied on top of the above mentioned binder material web. The entire sheet, which has been formed on the belt conveyor 20, is then carried through a suitable drying apparatus 40 where the sheet is thoroughly dried. The belt conveyor 20, after emerging from drying apparatus 40, carries the dried sheet through a conditioning apparatus 42 which supplies a controlled amount of moisture to the sheet to facilitate the lifting of the sheet from the conveyor belt and to make possible the proper cutting and handling of the finished product. The lifting of the sheet from the conveyor belt 20 is done at the end of the conveyor by a doctor knife 44 and the finished sheet is then guided into a lawn mower type cutting apparatus 46 where the sheet is cut into pieces of a desired size.

The water applicator 30, shown in FIG. 1 and illustrated in detail in FIGS. 2, 3 and 4, consists of a rubber roller or rubber covered roller 50 which is mounted on a horizontal shaft 52 rotably supported at each end by a bearing 54 each of which is secured to a vertical plate 56. Each plate 56 is slidably held in a vertical track 58 formed by suitable rails 59 secured to the main frame 60 of the machine. The lower end of each vertical plate 56 is pivotally connected with the upper end of a piston rod 62 which projects from the upper end of a vertical air cylinder 64 secured to the main frame 60 of the machine. Shaft 52, which carries the roller 50, is continuously rotated by a pulley 66 by means of a belt 68 which is connected to a suitable variable speed drive (not shown). The bottom portion of each air cylinder 64 is connected by means of a tube 70 to a suitable hand operated air valve (not shown) by means of which air pressure may be introduced into each cylinder to effect an upward motion of the piston within it which in turn causes an upward motion of the vertical plates 56 and the bearing brackets 54 mounted thereon. Since the bearing brackets 54 support the shaft 52 on which the roller 50 is mounted, the roller 50 may be raised above and away from belt to a desirable degree when it is not in operation. Above the top of roller 50 is suspended a suitably shaped skimming knife 72, as shown in FIGS. 2 and 3, which is provided at each end with an extension 74 by means of which the knife 72 is supported by a pair of adjustable supporting studs 76 each of which projects upwardly from the lower leg of a U-shaped bracket 78. A pair of compression springs 77 confined between the upper edges of extensions 74 and the upper legs of bracket 78 provides a resilient mounting and permits the adjusting of the skimming knife 72. Each bracket 78 is secured to a vertical plate 56 so that the raising and lowering of roller 50 does not effect the setting of the skimming knife 72 in its relation to roller 50 because knife 72 moves with the roller assembly. To each end of the skimming knife 72 there is secured a vertical plate 80' the lower portion of which loosely contacts an end of the roller 50 as illustrated in FIGS. 2 and 3. Between the plates 80 and roller 50 there is secured a U-shaped trough S2 to the front side of which is suitably mounted a rubber plate 84 having a lower beveled edge which contacts the surface of the roller 50 along its entire length. Thus plate 84, plates 80 and skimming knife 72 form a trough 86 across the top of roller 50 as shown in FIG. 3. In trough 86 there is suspended a horizontal tube 88 containing a plurality of suitable holes in its bottom portion so that any water supplied by means of the connected tube 90 runs into the trough 86. The tube 90 is connected to a suitable supply of water (not shown). In order to prevent the water supplied to trough 86 from seeping out between the vertical plate 80 and the ends of roller 50, each plate 80 is provided with an arcuate channel 92 in which is loosely inserted an arcuate sealing member 94 made of plastic, nylon or similar material. Each plate 80 carries a pair of compression springs 98 in suitable indentations 96 which press the sealing member 94 against the ends of the rotating roller 50 and assure a tight seal at the ends of the trough 86. Each sealing member 94 is provided with a suitable stud 100 which loosely protrudes through an aperture in its adjacent end plate 80 to serve as a retainer of the member 94 in channel 92. The trough 82 is provided with a drain pipe 102 to serve as an overflow to prevent the water level in trough 86 from reaching an undesirable height.

As illustrated in FIG. 3, the lower edge of the skimming knife 72 is accurately set with a clearance from the roller 50 to permit the latter to carry a film of water W of predetermined thickness to the moving belt conveyor 20 where the film of water, by means of a wiping action of the roller 50 against conveyor belt 20, is transferred to it.

It should be pointed out that the air cylinders 64 are double acting so that they maybe used to apply uniform nip pressure in the downward direction, as well as lifting the roller from the belt in the upward direction.

This method ofapplying water to the belt is very substantially superior to the spray techniques heretofore known and employed for this purpose. The water applicator of the present invention:

(a) provides a much more uniform coating;

([1) permits the thickness of water layer to be closely controlled;

(0) requires much less space, reducing the conveyor length substantially;

(d) eliminates the mist nuisance;

(e) is unaffected by non-uniformities or variations in thickness in the coated belt, the same quantity of material being laid down regardless of these variations.

It should be noted that the coating of a moving belt with a thin, uniform film of low viscosity fluid, such as water, is an extremely difficult problem. Attempts to employ other methods of application such as wiping the belt with saturated sponges, spraying with a brush, knife coating, overflowing weirs, etc. have been unsuccessful or unsatisfactory.

The conveyor belt 20 then carries the film of water beneath the first dust feeder 32, as shown in FIG. 1, where a layer of tobacco dust D is deposited onto the film of water W. The dust feeder 32, illustrated in detail in FIGS. 5 and 6, consists of a closed hopper 104 which, by means of a duct 106, is connected to a suitable tobacco dust supply (not shown). Across the center portion of the hopper 104 runs a continuously driven agitator shaft 108 which is provided with a plurality of hook-shaped agitator fingers 110 which prevent the formation of lumps and effect the flufiing of the tobacco dust in the hopper 104. It will be apparent that the fluffing agitator may be eliminated without departing from the invention when employing a feed which does not have a tendency to agglomerate into lumps. The hopper 104 is mounted on a suitable frame housing 112. The bottom of hopper 104 is provided with an opening 114 into which projects a portion of a knurled roller 116. The lower front portion of hopper 104 is also provided with an adjustable gate plate 118 pivotally suspended from a horizontal rod 120 which is secured in suitable lugs which are formed integrally with frame housing 112. The lower end of the gate plate 118 forms a tangent with the knurled roller 116 and the opening or space desired between the roller 116 and gate plate 118 may be set by means of a stop screw 122 carried by the gate plate 118 and kept in engagement with the end plates of the hopper by a suitable compression spring 124 confined between the inner wall of a frame bracket 126 and the front side of gate plate 118. The space which is adjustably set between the knurled roller 116 and the gate plate 118 controls the amount of tobacco dust carried out of the hopper 114 by the knurled roller 116.

The knurled roller 116 is mounted on a horizontal shaft 128 which is continuously driven through suitable sprockets and a chain by means of a variable speed drive unit 130 mounted on the top of the frame housing 112. The shaft 128 is rotatably supported by a U-shaped bearing bracket 132 mounted on a pair of spaced studs 134 which in turn are adjustably secured in a pair of suitable lugs 136 which form part of the frame housing 112. The adjustability of the knurled roller 116 is essential for obtaining the desired penetration compensating for the wear of the bristles of a cylindrical rotating brush 138 which engages with the rotating knurled roller 116. Brush 138 is mounted on a horizontal shaft 140 rotatably supported by suitable bearings in the frame housing 112. Shaft 140 has secured to it a pulley 142 which is driven by a belt 144 and a pulley 146 mounted on a motor shaft 148 of a motor 150 mounted on the lower portion of the frame housing 112. The rotary brush 138 is employed for the purpose of brushing the controlled amount of tobacco dust carried out of the hopper 104 by means of the rotating knurled roller 116 off the roller 116 and throwing it onto the water film W carried by the conveyor belt 20. This method of dust feeding has a decided advantage over systems heretofore employed of blowing dust onto the conveyor belt in that it eliminates the conveying of a the dust in a high velocity air stream while providing adequate penetration of the water or adhesive layer. This apparatus employed by the present invention applies the dust by centrifugal force through the air onto the water film on the moving conveyor. The outer periphery of the brush has a surface speed of 300 to 10,000 f.p.m. and preferably about 4,000 to 6,000 f.p.m. This relatively high velocity of the brush provides the essential effectiveness of this novel feeder, since it accelerates the dust particles to a velocity which gives comparatively excellent penetration of the film being coated. Beneath both edges of the conveyor belt 20 are resiliently mounted a pair of troughs 152 which extend through the entire length of the frame housing 112. The troughs 152 are employed for the purpose of collecting tobacco dust which is showered beyond the edges of belt 20. Each trough 152 is provided with a suitable vibrator 154 which moves dry dust forward to a suction funnel 156 mounted on the outside of housing 112. Since the suction funnel 156 extends transversely over the entire width of the conveyor belt 20, it will also pick up any loose dust which was not absorbed or held by the water film on the belt. The top portion of funnel 156 is connected by a tube 158 to a suitable suction system and dust collector (not shown). To keep the dust collected in the troughs 152. dry and free flowing, each trough 152 is provided with a suitable heating element 160. A butterfly valve 162 in suction tube 153 controls the amount of suction with a desired range. In order to maintain a constant level of the dust in the hopper 104 to assure uniform dust feeding, the hopper is provided with a conventional rotary valve (not shown) in the dust supply system to which hopper 104 is connected by tube 106. When the dust in the hopper reaches a predetermined level, the sensor 164 causes the rotary valve in the supply line to close and, when dust is needed in the hopper, the sensor 164 efiects the opening of the rotary valve. A conventional vibrator unit 166 is secured to one of the outer walls of the hopper 104 to assure a free flowing movement of tobacco dust within the hopper 104. In order to expel dampness from the dust feeder 32 which may lead to lumping and clogging of the tobacco dust, a hot air pipe 168 may protrude through the frame housing 112 in a suitable manner. Inside the frame housing 112 there is also adjustably mounted a suitably shaped deflector plate 170 which keeps the dust stream thrown onto the conveyor belt within a predetermined area.

This technique of relatively high speed operation i.e., greater than about 500 feet per minute, is also much superior to the blowing methods because it is unnecessary to circulate a great excess of dust. The percentage of dust deposited by the high speed brush application of the invention is very much greater than that deposited by the blowing method and in fact approaches 80% or more. Furthermore, we have found that by the blowing technique it is impossible to control the amount of dust deposited whereas with the high speed brush feeder the amount of dust deposited can be increased or decreased at will, by correspondingly increasing or decreasing the speed of the knurled feed roll.

It should also be noted that the high speed brush dust feeder of the invention differs from previously disclosed brush feeders in that our brush is specifically designed and required to operate at relatively high speed (i.e., a surface speed greater than 500 feet per minute and preferably in the range of 2,000 to 10,000 feet per minute) so as to impel and impart to the dust a high kinetic velocity; this velocity is considered generally about 60% to 95% of the brush surface velocity. Although the use of brush feeders has been considered heretofore such dust feeders operate at very low speeds and virtually allow the dust to fall by gravity. We have discovered a suprisingly eflfective film penetration and advantageous product is obtainable by use of the high speed brush herein described.

It will be apparent that the use of this high speed brush dust feeder is not necessarily limited to the manufacture of tobacco sheet but can be used to coat any moving surface with a dry powdered material, especially where some penetration of the surface being coated is required. Other examples of its use would be the prep aration of abrasive paper or cloth by depositing abrasive powder on moving webs of paper or cloth. As used herein the term dust connotes material particles sizes generally below 2 mesh and preferably in the range of 30-325 U.S. standard mesh.

The dust covered water film is carried by the conveyor belt 20 from the dust feeder 32 into the dryer 34 as shown in FIG. 1. Dryer 34 consists of a housing 172 in which is moveably mounted a self-aligning steam box 174. The dryer 34, illustrated in detail in FIGS. 7 and 8, is substantially of the same construction as the one illustrated and described in the patent application for Steam Drying Method and Apparatus, Ser. No. 814,762 filed on May 21, 1959, now abandoned. Steam box 174 is mounted on a pair of spaced transverse bars 176, each of which is provided at their outer ends with a pair of downwardly projecting forked bearing brackets 178. Each bracket 178 rotatably supports a horizontal shaft 180 on which is mounted a pair of grooved wheels 182. Each pair of wheels 182 supporting each transverse bar 176 rides upon a transverse track 184 each of which is supported and secured to a cross beam 186 which, in turn, is mounted on a pair of longitudinal frame members 188. By supporting the steam box 174 on wheels riding upon transverse tracks, the steam box may be moved freely in a lateral direction to follow any lateral travel of the conveyor belt 20 which forms the moving cover for the steam box. A constant alignment of the steam box with the conveyor belt keeps the steam and vapor loss at a minimum. This alignment is accomplished by means of a position indicator arm 190 which is pivotally mounted to contact and engage with its free end one edge of the endless conveyor 20 as illustrated in FIGS. 7 and 8. Arm 190 projects from and actuates a position transmitter 192 which, by means of a tube 194, is connected to a horizontal air cylinder 196 mounted by means of a suitable bracket 198 on a longitudinal frame member 188. The air cylinder 196 is provided with a piston (not shown) which, in turn, is connected with a piston rod 200 having a free end which projects from the cylinder 196 and is pivotally connected with a forked lug 202 which is formed integrally with and projects from a bracket 204 mounted on the side of the steam box 174. Since the indicator arm 190 is in constant contact with the side edge of the moving conveyor band 20, any lateral movement of the latter causes a corresponding movement of the indicator arm 190 which, in turn, actuates a valve within the position transmitter 192 which transmits movements by means of the tube 194 to the air cylinder 196 to move piston rod 200 in or out. Since the end of the piston rod 200 is connected to the steam box 174, the latter precisely follows any lateral movement of the conveyor 20 and remains in alignment with it at all times. For any given position of the indicator arm there is a particular air signal to the air cylinder which through a closed loop feedback system provides in turn a particular position of the piston and its connections. Both the air cylinder 196 and the position indicator 192 are standard conventional pieces of equipment.

The steam box 174 is provided with transverse tubes (not shown) which are connected to each other by suitable pipes in the same manner as described and illustrated in the above mentioned pending patent application Ser. No. 814,762. The pipes within the steam box are connected to a source of steam (not shown). The transverse tubes within the steam box 174 are provided with a plurality of spaced jets or nozzles for directing the steam towards the lower side of the passing 296 which are mounted on the longitudinal frame members 298 of the machine. The cooling box 290 is the exact width of the belt 20 and is kept in constant alignment with belt 20 by means of an indicator arm 300 projecting from a position transmitter 302 which, by means of a tube 304, is connected to an air cylinder 306. Air cylinder 306 actuates a piston rod 308, the outwardly projecting end of which is pivotally connected with the rolling carriage structure of the cooling box 290. The upper free end of the indicator arm 300 engages one edge of the conveyor belt 20 so that any lateral movement of the conveyor belt 20 actuates the position transmitter 302 so as to effect a corresponding movement of the piston rod 308 to align the cooling box with the belt 20. This aligning system is identical with and operates in the same manner as the aligning system used for the steam boxes 174 and 278. Within the cooling box 290 there are mounted a plurality of transverse pipes 310 which are connected to each other and to a source of cold water (not shown). The pipes 310 are provided with a plurality of jets or nozzles 312 located to direct a cold spray against the bottom of the conveyor belt 20 as illustrated in FIG. 12. Since the endless steel belt conveyor 20 is hot when entering the conditioner unit 42, the spray of cold water onto the bottom of the belt 20 cools it. Spray water drops to the bottom of the box 290 and flows out through a drain duct 314 leading to a catching basin 316 which, in turn, is connected to a drain pipe 318 leading out of the machine. Within the upper portion of the housing 288 across the top of the belt conveyor 20 there are mounted a plurality of steam pipes 320 which are connected to a steam source (not shown) and provided with a plurality of jets or nozzles 322 positioned to direct a blast of steam directly onto the sheet carried by the conveyor belt 20 through the conditioner unit 42. The steam sprayed on the cooled sheet condenses to raise its moisture content to a desired percentage to make it pliable for further processing. In order to prevent any condensation which may form on the inner walls of housing 288 from dripping onto the sheet, the upper edges of the belt entrance and exit slot of the housing 288 are provided with a steam pipe 324 which is hot enough to evaporate any condensation and prevent it from dropping onto the sheet to form wet spots. The bottom portion of housing 288 is provided with a suitable suction duct 326 which is connected to a suction fan unit 328 which sucks fresh air through an opening 330 in the top portion of housing 288 and through the entire unit 42.

Insofar as is known, the hereabove described sheet conditioner is novel. It provides a very effective means of controlling final sheet moisture. Specific final moisture contents within the range of 10% to 40% basis can be obtained. Control is obtained by adjusting the volume and temperature of cold water sprayed on the belt bottom and by adjusting the volume of steam and air drawn across the top of the sheet.

In operation, the steam, water and air flows are usually set at specific rates and control is exercised by thermostatic control of the water temperature. This may be effected, for example, by using a recirculating water supply of constant volume (not shown) to which quantities of cold water are added as required, displacing equivalent quantities of warmer water in the system. An alternate means would be circulating the water supply through a refrigerating heat exchanger as required. For Wide variations in desired final sheet moisture, as for example, between 12% and 25%, it is necessary to make adjustments to the flow rates of the air, water and steam. Once the level has been set the temperature control takes over, con trolling the sheet moisture between say 11.5% and 12.5% at the 12% level and between 24% and 26% at the 25% level.

An additional advantage of the herein provided conditioner over other methods of conditioning tobacco sheet resides in the fact that it requires a minimum of space and apparatus while providing a maximum of uniformity and control.

In methods employed in the prior art as far as is known, the sheet cannot be conditioned on the same conveyor on which it is made. Instead, the sheet, after being made, is re-wet to a moisture considerably above that at which it is to be stored and used, then is doctored off and redried on another drying conveyor. The present invention eliminates the need for this extra drying conveyor and accomplishes the same result in a relatively minor addition to space on the sheet making conveyor.

It will be understood that the use of this conditioner is not limited to the conditioning of tobacco sheet but can be used to condition any material being carried on an impervious, heat conductive belt.

The sheet emerges from the housing 288 with the desired moisture content and, as shown in FIG. 1, is lifted off the conveyor belt 20 by means of a conventional doctor knife 44 to be fed into the cutting unit 46 to be cut or shredded as desired. After the sheet is lifted from the endless steel band conveyor belt 20, the latter is contacted by a plurality of wipers 332 to assure its having a clean surface when it again reaches the water applicator 30. A plow 334 which contacts the upper surface of the lower run of belt 20, is provided to clean it of any debris which may have been dropped on it.

Because the conveyor belt 20 is very long, it is important to control and counteract any lateral wandering of it. For this reason the machine is equipped with a continuous modulating tracking system to provide a corrective force in direct proportion to the amount of wandering of the conveyor belt 20. This tracking system, illustrated in FIGS. 13 to 16, consists of a position indicator arm 336 projecting from a position transmitter 338 and engaging with its upper free end one edge of the upper run of conveyor belt 20. The position transmitter 338, by means of a tube 340, is connected to a source of compressed ai-r (not shown). The transmitter 338, by means of a tube 342, is also connected to a vertical air cylinder 344 and by means of tube 346 to air cylinder 348. Both air cylinders 346 and 348 are mounted on frame members of the machine and have the piston rods 352 project downward through and into the bearing frame 350 as illustrated in FIGS. 15 and 16 of the drawing. From the lower free end of each piston rod 352 there is suspended a bearing block 354 which slidably engages a pair of spaced vertical rails 356 secured to the frame 350. Each bearing block 354 is provided with a spherical selfaligning bearing 358 which rotatably supports one end of a shaft 360 to which is mounted a belt control roller 362 which engages the top surface of the lower run of belt 20 as illustrated in FIGS. 1, 13 and 14. Each bearing frame 350 is provided with an upper lug 364 and a lower lug 366 both of which are slidingly engaged be tween the vertical tracks 368 and the retainer bars 370. The track 368 is rigidly secured to the main structure of the machine and rotably supports a vertical spindle 372 which is provided with a smooth upper portion 374 and a threaded lower portion 376. The threaded lower portion 376 of spindle 372 engages with a. threaded bore 378 of the lower bearing frame lug 366 while the upper bearing frame lug 364 is just provided with a clearance hole 380 to accommodate the smooth upper portion 374 of spindle 372. It is self-evident that by turning the spindle 372 the bearing frame 350 may be raised or lowered to a desired position.

The tracking system operates in the following manner. When the conveyor belt 20 runs true and even as illustrated in FIG. 13, the indicator arm 336 is in a vertical position and causes the position transmitter 338 to keep the air pressure in the vertical air cylinders 344 and 348 in balance to lock the pistons within these cylinders and keep the control roller 362 in a horizontal position. As soon as the belt 20 wanders off to one side as illustrated in FIG. 14, the indicator arm 336 will follow this movement and tilt to the side toward which the belt wanders. This tilting the indicator arm 336 causes a shifting of valves within the position transmitter 338 in such a manner as to permit the air pressure to reach only the air cylinder on the side of the belt towards which the belt wanders while cutting off the air in the cylinder on the opposite side. The piston within the cylinder to which air pressure is applied is forced downward and consequently the piston rod 352 and the bearing block 354 that support the end of the shaft 360 carrying the control roller 362 is moved downward causing the roller 362 to assume an angular position. The increase of tension in one side of belt 20 forces the belt to wander back to its normal position. The tracking system is so designed so that movements of the vertical pistons within the air cylinders 344 and 348 are proportional to the horizontal swings of the indicator arm 336 and, consequently, the horizontal wandering of the belt 20. When the belt 20 moves from its normal position it also moves the indicator arm 336 which in turn causes one or the other of the vertical air cylinders to take corrective movement in proportion to the deviation of the belt 20 from normality. Restoration to vertical of arm 336 effects a decrease of the air pressure in that cylinder to which it was applied for correction. Thus, when arm 336 reaches its normal vertical position, the air pressure in both vertical cylinders will again be equal and the control roller 362 will resume its horizontal position to evenly contact the belt 20. It will be apparent that the tracking arrangement herein described is useful in tracking any metallic band conveyor and hence should not be limited in application to its use in conjunction with any specific web forming conveyor construction.

While the invention for the purpose of providing a more appropriately specific embodiment has been described in connection with forming sheet tobacco it is not to be interpreted as so limited but can be used in the manufacture of any material which it is desired to make by gluing two layers of dust together. Some examples of other uses are in the manufacture of (1) flexible wood sheet made by applying sawdust or wood flour with the two dust-feeders and a suitable adhesive with the base-web applicator; (2) a flexible leather sheet made by applying ground leather particles with the two dustfeeders and a suitable adhesive with the base-web applicator; (3) food materials such as luncheon meat by applying ground meat with dust feeders and a suitable adhesive with the base-web applicator; (4) two sided abrasive sheets, and the like.

While we have shown our invention in the best form known to us, it will nevertheless be understood that this is purely exemplary and that modifications in the construction, arrangement, and combination of parts and the substitution of equivalents mechanically and otherwise, may be made without departing from the spirit of the invention, except as it may be limited in the appended claims.

What is claimed is:

1. An apparatus for forming continuous self-sustainable sheet material comprising a moving endless belt, means to deposit a thin film of liquid on said belt, at least one means to apply a layer of dry finely divided material to the wet belt, said means for applying the layer of dry material comprising in combination a knurled rotatable roller and a rotatable cylindrical brush contacting said knurled roller, means for applying said dry material supply to said knurled roller so that material picked up by said brush from said knurled roller is cast downward, said knurled roller and said brush being disposed transversely above said belt, at least one heating means for drying wet layers of material deposited on said belt, means to apply a layer binding material onto said belt, said means for applying the layer binding material comprising a rotating feed drum, a rotating refuser drum disposed with a light clearance alongside said feed drum, said feed drum rotating with its upper surface moving downward toward said refuser drum and said refuser drum rotating with its upper surface moving upward away from said feed drum, means to introduce liquid binding material between said drums, a rotating high speed cylindrical brush disposed across said belt and contacting said feed drum to cast a second layer of finely divided material downward onto said belt, and means to remove the integrated bound layers of material from said belt as a continuous self-supportable flexible sheet.

2. In an apparatus for forming tobacco sheets, a moving endless belt, means to deposit a thin film of liquid, on said belt, at least one means to apply a layer of dry dust to the wet belt, said means to apply a layer of dry dust having a hopper, a tobacco dust supply to said hopper, a knurled and rotating roller extending into the bottom of said hopper with a small clearance between said roller and the bottom of one side of said hopper, and a rotating cylindrical brush contacting said knurled roller throwing dust carried from said hopper by said knurled roller downward, said knurled roller and said brush being disposed transversely above said belt, at least one heating means drying wet layers of tobacco dust on said belt, means to apply a layer of binding material onto said belt, said means to apply a layer of binding material having a rotating feed drum, a rotating refuser drum disposed with a slight clearance alongside said feed drum, said feed drum rotating with its upper surface moving downward toward said refuser drum and said refuser drum rotating with its upper surface moving upward away from said feed drum, means to introduce liquid binding material between said drums and a rotating high speed cylindrical brush disposed across said belt and contacting said feed drum to throw a second layer of tobacco downward onto said belt, and means to remove layers of (tobacco dust and binding) material from said belt (as tobacco sheet).

3. The combination according to claim 2 comprising means to cool the underside of said belt and means for moistening the layers on said belt, said cooling and moistening means being arranged in front of the means to remove the layers from said belt.

4. An apparatus for forming tobacco sheet comprising, in combination, two pulleys, means to drive at least one of said pulleys, an endless metal belt disposed over said pulleys, means to deposit a thin film of water on said belt, first means to apply a layer of dry dust to the wet belt, said first means having a hopper, a tobacco dust supply to said hopper, a knurled and rotating roller extending with a small clearance into the bottom of said hopper and a rotating cylindrical brush contacting said knurled roller to throw dust carried from said hopper by said knurled roller downward, said knurled roller and said brush being disposed across said belt, a suction funnel disposed across said belt drawing up dust not held to said belt by the water film, first heating means drying the wet layer of tobacco dust on said belt onto said dried tobacco layer, said means to apply a layer of binding material having a rotating feed drum, a rotating refuser drum disposed with slight clearance alongside said feed drum, said feed drum rotating with its upper portion moving downward toward said refuser drum, and said refuser drum rotating with its upper portion moving upward away from said feed drum, means to introduce liquid binding material between said drums, and a rotating cylindrical brush disposed across said belt and contacting said feed drum throwing binding material downward onto said belt, a second means to apply a layer of dry dust to said belt similar to said first means, second heating means drying the layers of tobacco dust and binding material on said belt, a sheet conditioning apparatus raising the moisture content of the layers on said belt, said sheet conditioning apparatus having means to cool the underside of said belt and steam nozzles spraying the layers on said belt with steam, and means to remove the layers of tobacco dust and binding material from said belt as tobacco sheet.

5. The combination according to claim 2 with the addition of means to sense lateral movements of said belt 13 and means to increase the tension in said belt on the side of'said belt towards which said belt has laterally moved.

6. In an apparatus for forming a continuous self-sustainable flexible sheet product, the combination comprising a movable metal belt, means to apply a thin film of liquid to said belt, said means comprising, in combination, a roller having a resilient outer surface disposed across said belt and contacting said belt, drive means rotating said roller so that the surface of said roller contacting said belt moves in the opposite direction from said belt, and a liquid reservoir above said roller, said liquid reservoir having a rear seal extending across said roller and contacting said roller preventing loss of liquid between said rear seal and said roller, two end seals extending forward from said rear seal, said end seals contacting the end of said roller to prevent loss of liquid between said roller and between said end seals, a skimming knife extending across the front of said roller between said end seals, and means to adjustably position said skimming knife above the top surface of said roller to allow said roller to carry a thin film of liquid from said reservoir to be deposited on said belt.

7. In a tobacco sheet forming apparatus having a moving metal belt, means to apply a thin film of water to said belt, said means comprising, in combination, a roller having a resilient outer surface disposed across said belt and contacting said belt, drive means rotating said roller so that the surface of said roller contacting said belt moves in the opopsite direction from said belt, and a water reservoir above said roller, said water reservoir having a rear seal extending across said roller and contacting said roller preventing loss of water between said rear seal and said roller, two end seals extending forward from said rear seal, said end seals contacting the ends of said roller to prevent loss of water between said roller and said end seals, a skimming knife extending across the front of said roller between said end seals, and means to adjustably position said skimming knife above the top surface of said roller to allow said roller to carry a thin film of water from said reservoir to be deposited on said belt.

8. In an apparatus for forming a continuous self-sustainable flexible sheet product, the combination comprising a moveable belt, means to apply a layer of dry finely particulated material to said belt, said means comprising, in combination, a hopper, a particulated material supply for said hopper, a roller extending into the bottom of said hopper, said roller having a roughened surface and said roller extending with slight clearance from said roller, a cylindrical brush contacting said roller below the side of said hopper extending with a slight clearance from one side of said hopper, drive means for said cylindrical brush rotating the side of said cylindrical brush contacting said roller downward throwing particulated material carried from said hopper by said roller downward onto said belt.

9. In a tobacco sheet forming apparatus having a moving belt, means to apply a layer of dry dust to said belt, said means comprising, in combination, a hopper, a tobacco dust supply to said hopper, a roller extending into the bottom of said hopper, said roller having a roughened surface and said roller extending with slight clearance from one side of said hopper, drive means to rotate said roller toward the side of said hopper extending with a slight clearance from said roller, a cylindrical brush contacting said roller below the side of said hopper extending with a slight clearance from said roller, and drive means for said cylindrical brush rotating the side of said cylindrical brush contacting said roller downward throwing dust carried from said hopper by said roller downward onto said belt.

10. In a tobacco sheet forming apparatus having a moving belt, means to apply a thin layer of dry tobacco dust to said belt comprising, in combination, a hopper, a tobacco dust supply for said hopper, a knurled roller extending upward into said hopper and disposed across said belt, a front wall of said hopper disposed along one side of said roller, support means for said front wall allowing said front wall to be adjustably positioned with slight clearance from said roller, drive means for said roller rotating said roller toward said front wall, a cylindrical brush disposed across said belt contacting said roller below said front wall, and drive means rotating said cylindrical brush with the portion of said cylindrical brush contacting said roller moving downward to throw dust carried by said roller from said hopper downward onto said belt.

11. The combination according to claim 8 with the addition of means to adjustably position said roller relative to said brush.

12. In an apparatus for forming a continuous self-sustaining flexible sheet product the combination comprising a movable belt, means to deposit a layer of liquid bind ing material upon said belt, said means comprising, in combination, a feed roller disposed across said belt, a refuser roller disposed across said belt alongside said feed roller with slight clearance between said rollers, drive means for rotating said rollers moving the portion of said feed roller adjacent to said refuser roller downward and moving the portion of said refuser roller adjacent to said drive roller upward, means flowing liquid binding material from above between said two rollers, a cylindrical brush contacting said feed roller, and drive means rotating said cylindrical brush throwing binding material from said feed roller onto said belt.

13. In a tobacco sheet forming apparatus having a moving belt, means to deposit a layer of liquid binding material upon said belt, said means comprising, in combination, a feed roller disposed across said belt, a refuser roller disposed across said belt alongside said feed roller with slight clearance between said rollers, drive means for rotating said rollers moving the portion of said feed roller adjacent to said refuser roller downward and moving the portion of said refuser roller adjacent to said drive roller upward, means flowing liquid binding material from above between said two rollers, a cylindrical brush contacting said feed roller, and drive means rotating said cylindrical brush throwing binding material from said feed roller onto said belt.

14. The combination according to claim 11 wherein said refuser roller is adjustably positioned relative to said feed roller and said feed roller is adjustably positioned relative to said cylindrical brush.

15. In a tobacco sheet forming apparatus having a first pulley, a second pulley, means to drive at least one of said pulleys, and a horizontal metal belt disposed about said pulleys, a tobacco sheet conditioning apparatus comprising, in combination, transverse tracks disposed beneath said belt, a water box of the same width as said belt slidably mounted beneath said belt on said tracks, water pipes within said water box, a source of water connected to said pipes, nozzles in said water pipes directing a spray of water upward onto the under surface of said belt, means directing a spray of steam downward onto the tobacco sheet on said cooled belt, drain means from said water box, means sensing lateral motion of said belt, and means responsive to said means sensing lateral motion of said belt keeping said water box directly beneath said belt.

16. In a tobacco sheet forming apparatus having a first pulley, a second pulley, means to drive at least one of said pulleys, and a horizontal belt disposed about said pulleys, transverse tracks disposed beneath a run of said belt, heating means of the same width as said belt slidably disposed on said tracks beneath said belt, means sensing lateral motion of said belt, and means responsive to said means sensing lateral motion of said belt keeping said heating means directly below said belt.

(References on following page) UNITED STATES PATENTS Crean Dec. 31, 1901 Dilg Feb. 3, 1914 5 Febles May 18, 1926 Febles Mar. 5, 1929 Brown et a1. Oct. 24, 1933 Manning Apr. 4, 1939 Garber Nov. 22, 1949 Kendall Sept. 25, 1951 Seifried June 10, 1952 Bolton Apr. 26, 1955 Murphy Dec. 6, 1955 Hungerford et a1 Feb. 14, 1956 Hungerford et a1. Feb. 14, 1956 Ahlich May 6, 1958 Buteux et al. Dec. 9, 1958

Claims (1)

1. AN APPARATUS FOR FORMING CONTINUOUS SELF-SUSTAINABLE SHEET MATERIAL COMPRISING A MOVING ENDLESS BELT, MEANS TO DEPOSIT A THIN FILM OF LIQUID ON SAID BELT, AT LEAST ONE MEANS TO APPLY A LAYER OF DRY FINELY DIVIDED MATERIAL TO THE WET BELT, SAID MEANS FOR APPLYING THE LAYER OF DRY MATERIAL COMPRISING IN COMBINATION A KNURLED ROTATABLE ROLLER AND A ROTATABLE CYLINDRICAL BRUSH CONTACTING SAID KNURLED ROLLER, MEANS FOR APPLYING SAID DRY MATERIAL SUPPLY TO SAID KNURLED ROLLER SO THAT MATERIAL PICKED UP BY SAID BRUSH FROM SAID KNURLED ROLLER IS CAST DOWNWARD, SAID KNURLED ROLLER AND SAID BRUSH BEING DISPOSED TRANSVERSELY ABOVE SAID BELT, AT LEAST ONE HEATING MEANS FOR DRYING WET LAYERS OF MATERIAL DEPOSITED ON SAID BELT, MEANS TO APPLY A LAYER BINDING MATERIAL ONTO SAID BELT, SAID MEANS FOR APPLYING THE LAYER BINDING MATERIAL COMPRISING A ROTATING FEED DRUM, A ROTATING REFUSER DRUM DISPOSED WITH A LIGHT CLEARANCE ALONGSIDE SAID FEED DRUM, SAID FEED DRUM ROTATING WITH ITS UPPER SURFACE MOVING DOWNWARD TOWARD SAID REFUSER DRUM AND SAID REFUSER DRUM ROTATING WITH ITS UPPER SURFACE MOVING UPWARD AWAY FROM SAID FEED DRUM, MEANS TO INTRODUCE LIQUID BINDING MATERIAL BETWEEN SAID DRUMS, A ROTATING HIGH SPEED CYLINDRICAL BRUSH DISPOSED ACROSS SAID BELT AND CONTACTING SAID FEED DRUM TO CAST A SECOND LAYER OF FINELY DIVIDED MATERIAL DOWNWARD ONTO SAID BELT, AND MEANS TO REMOVE THE INTEGRATED BOUND LAYERS OF MATERIAL FROM SAID BELT AS A CONTINUOUS SELF-SUPPORTABLE FLEXIBLE SHEET.

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