Patent Publication Number: US-6988501-B2

Title: Tobacco processing machine

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a machine for processing tobacco bales or slices. 
   Currently, in lines for processing tobacco at the manufacturing level, raw tobacco bales are broken up by means of a process that is commonly known as slicing and direct conditioning process. 
   The tobacco bales, once freed from their packaging, depending on their dimensions may be subjected to slicing, so as to reduce them to dimensions that are compatible with the machines designed to process them. 
   The tobacco slices or intact bales are then conveyed to a known type of machine, designated by the reference numeral  1  in  FIGS. 1 and 2 , which is conveniently constituted by a frame  2  that is shaped like a cylinder or a rotating drum. 
   This known type of machine  1  for processing tobacco bales or slices must break them up, heat the resulting intermediate product, designated by the reference numeral  3 , to the intended temperature, maintain its temperature for a preset time, known as transit time, and finally humidify the intermediate product until a preset level of humidity is reached. 
   The cylindrical frame  2  rotates about its own axis, which is conveniently inclined downward so as to allow the simultaneous advancement of the tobacco inside the cylinder. 
   The tobacco is moved by means of a plurality of radial rods, designated by the reference numeral  4 , which protrude inside the cylinder and are suitable to lift the intermediate product  3 . 
   The product, once it has reached a position that is proximate to the upper end of the cylinder, falls back, forming a downward stream  5 , which by way of the inclination of the axis falls in a more advanced position along the axis of the cylinder. 
   In these conventional machines  1  there are provided, at one or both ends of the cylindrical frame  2 , one or more nozzles, designated by the reference numeral  6 , which are adapted to introduce steam or atomize water by means of steam or compressed air (using therefore two paired nozzles) so as to both humidify and heat the intermediate product  3 . 
   The nozzles  6  are advantageously constituted by double water/steam or water/compressed air nozzles, in which the gaseous element is designed to atomize the water. 
   Moreover, the machine  1  is advantageously provided with an external duct  7 , which comprises a fan  8  and is adapted to generate a current of air that flows, inside the cylinder, in equicurrent or countercurrent with respect to the flow of tobacco, so as to render the humidification and/or heating of the intermediate product  3  as uniform as possible. 
   In these conventional machines  1 , the transit speed and therefore the retention time of the tobacco are determined first of all by the degree of inclination of the drum-like or cylindrical frame  3  and by the speed at which the air and the steam or water are introduced at the ends of the cylinder. 
   Depending on all of the above variables, a curve is generated which characterizes the behavior of the temperature in the environment inside the cylinder. 
   For optimum treatment of the tobacco, this temperature should have a behavior that has a peak at the input end, a subsequent constant behavior up to 80–85% of the length of the cylinder, and finally a decrease in the temperature in the output region, where an injection of conditioning water is usually provided. 
   The main drawback of these conventional tobacco processing machines  1  is that the direct conditioning systems with which they are equipped, described briefly above, often perform a scarcely effective humidification and/or heating of the intermediate product  3 . 
   In particular, it is very difficult to control the behavior of the temperature curve along the axis of the cylinder: the injection of the steam, which it the primary cause of the heating of the tobacco, causes only at the ends of the drum-like frame a heating that is characterized by two temperature peaks located at the input and output of the cylinder and by a central trough that covers most of the length of said cylinder. 
   The current of optionally preheated air, which should convey steam and water along the entire extension of the cylinder, is in practice scarcely effective in equalizing the temperature behavior. 
   Moreover, it worsens the drawback constituted by the difficulties in controlling the transit time of the tobacco inside the machine, since it acts differently depending on the characteristics of the tobacco being treated. 
   In particular, the transit time can be altered by the air stream due to the different density of the tobacco, since there is a greater or smaller propulsion effect (in the case of an equicurrent air stream) or a greater or smaller slowing or retention effect (in the case of a countercurrent air stream) depending on the greater or lower lightness of the tobacco. 
   Another drawback consists in that the weight and consistency of the tobacco in transit cause a variation in the transit speed also as a function of the number and arrangement of the nozzles  6  for the injection of the steam and water from the ends of the frame. 
   More specifically, injection at the loading end tends to increase the advancement speed of the intermediate product, while injection at the unloading end tends to retain the tobacco inside the cylinder. 
   Some conventional machines  1  can be equipped with mechanical means adapted to adjust the transit speed according to the quality and characteristics of the tobacco; however, such mechanical means are highly ineffective, since they assume a control of the rotation rate or inclination of the cylinder. 
   Actually, the inclination of the axis is usually fixed, and even if it were made variable it could not be adjusted continuously and at the same time effectively in order to cope with the sometimes rapid behavior variations that depend on the quality of the product being treated. 
   Moreover, the range available for varying the speed of the cylinder is very limited, since in order to properly form the falling stream  5  the product must fall from a rather narrow region of the upper end of the cylinder, designated by the angle α in  FIG. 2 . 
   As a partial remedy to the above-described drawbacks, machines for treating tobacco are known which are designated by the reference numeral  11  in  FIGS. 3 and 4  and have a device  12  for injecting steam and water that is advantageously constituted by one or more tubes  13  arranged inside the cylindrical frame, designated by the reference numeral  14 . 
   The tubes  13  are supported at their free ends and have, along part or all of their length, suitable nozzles  15  for injecting steam, so as to achieve an injection direction that is approximately perpendicular to the advancement direction of the intermediate product, designated by the reference numeral  16  in the figures. 
   In this manner, the influence of the steam injection on the transit speed is reduced and at the same time the use of an air current for entrainment along the axis of the cylinder is rendered substantially unnecessary. 
   The tubes  13  are usually arranged in the opposite position with respect to the product fall region, designated by the reference numeral  17  in  FIGS. 3 and 4 . 
   One drawback of conventional machine  11  is the fact that it is often difficult to insert one or more tubes  13 , which are necessary of the self-supporting type, along the entire length of the frame  14 , which can in some cases exceed ten meters. 
   Another important drawback is that the radial rods, generally designated by the reference numeral  18 , which protrude inside the cylinder and are designed to move and lift the intermediate product  16 , force to place the tubes  13  so that they are far from the internal surface of the cylinder, in order to avoid interference with the rods  18 . 
   Due to the length of the rods  18 , therefore, the tube  13  cannot be placed in the position that is most convenient to allow optimum steam injection. 
   Another severe problem can be due to the continuous impact between the tobacco slices or bales and the tubes  13 , which can lead to an excessive mechanical stress of said tubes and therefore to consequent malfunctions or breakdowns of said machine  11 . 
   A further drawback of the conventional machines  11  is that leaves or strips of tobacco, designated by the reference numeral  19  in  FIG. 4 , can straddle said one or more tubes  13  and remain there until they are removed by chance by additional incoming intermediate product  16  or until the machine is cleaned at the end of the production cycle. 
   In the first case, the tobacco retained by the tube  13  is humidified excessively, and its return to the main stream of intermediate product  16  generates a critical quality problem. 
   In the second case, instead, a possibly considerable quantity of intermediate product is wasted. 
   There are known mechanical means for limiting the straddling of the leaves or for cleaning the tube  13  continuously, such as for example periodic or continuous rotation of the tube, the arrangement of rotating cleaning brushes, usually located above the tube, or the arrangement of curved tile-shaped protections above the tube. 
   However, all these mechanical means are very complicated and scarcely effective and require considerable maintenance. 
   SUMMARY OF THE INVENTION 
   The aim of the present invention is to solve the above-described drawbacks by providing a tobacco processing machine that allows optimum treatment of the tobacco regardless of its density or lightness. 
   Within this aim, an object of the present invention is to provide a tobacco processing machine that allows to perform optimum humidification and/or effective heating of the intermediate product uniformly along the entire length of the cylindrical frame. 
   Another object is to provide a tobacco processing machine that does not require an air stream along the cylinder. 
   Another important advantage is the possibility to differentiate the amount of steam or water injected in the different parts of the length of the cylinder, so as to control the shape of the temperature curve and divide the cylinder into a plurality of regions. 
   A further object is to provide an optimum injection of the steam along the falling stream of tobacco, with a consequent substantial improvement of the efficiency of the machine. 
   A further object is to simplify and speed up the cleaning process at the end of the production cycle. 
   A further object is to provide a tobacco processing machine that is structurally simple and reliable and has low manufacturing costs. 
   This aim and these and other objects that will become better apparent hereinafter are achieved by a tobacco processing machine, which comprises a frame that is cylindrical and hollow, has an inclined axis, and rotates axially, for breaking up tobacco bales or slices, inside which means for moving said tobacco are provided which are constituted by a plurality of rods, characterized in that it comprises means for feeding steam and/or water and/or another fluid, said means being provided on an inner lateral surface of said cylinder and rotating with it. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the present invention will become better apparent from the following detailed description of a particular embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: 
       FIGS. 1 and 2  are respectively a side view and a front view of a first conventional tobacco processing machine; 
       FIGS. 3 and 4  are respectively a side view and a front view of a second conventional tobacco processing machine; 
       FIGS. 5 and 6  are respectively a side view and a front view of tobacco processing machine according to the present invention; 
       FIG. 7  is a front view of a detail of  FIG. 6 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the figures, the reference numeral  51  designates a machine for processing tobacco bales or slices, advantageously constituted by a frame  52 , which is advantageously cylindrical, conveniently hollow and arranged so that its axis is slightly inclined. 
   The frame  52  has, at its free ends, a tobacco input region  53   a  and an output region  53   b  for a intermediate product, which is designated by the reference numeral  54  in  FIG. 6 ; in particular, the frame  52  is inclined so that the output region  53   b  is located at a lower level than the input region  53   a.    
   The frame  52  rotates about its own axis so as to allow the intermediate product  54  to move toward the output region  53   b.    
   During its rotation, the frame  52  also breaks up the tobacco bales or slices, advantageously through suitable movement means, which in this particular embodiment are constituted by multiple rods  55  that protrude radially inside the frame  52 . 
   The machine  51  further comprises humidification and/or heating means, which are advantageously obtained by way of steam feeder means, designated by the reference numeral  56 , which are preferably formed at the rods  55 . 
   The rods  55  are in fact conveniently perforated axially, so as to obtain respective nozzles, one of which is designated by the reference numeral  57  in  FIG. 7 . 
   At the first free end, designated by the reference numeral  58   a , of each rod  55  it is possible to use individual or double nozzles, depending on the type of fluid to be injected into the intermediate product  54 . 
   At a second free end  58   b , which lies opposite the first one, the rods  55  are associated with, or rigidly coupled to, the internal surface  59  of the frame  52  at respective holes, not shown, for connection to a duct  60  and a tube  61 . 
   In the embodiment illustrated by way of example in  FIGS. 5 to 7 , the machine  51  has six tubes  61 , which are arranged longitudinally around the outer surface of the frame  52  in mutually equidistant positions. 
   Such tubes are advantageously fed by means of a single manifold, designated by the reference numeral  62 , which is arranged annularly with respect to the frame  52 , for example proximate to the output region  53   b.    
   The machine  51  can advantageously comprise means for temporarily and selectively deactivating the steam feeder means  56 , so as to allow to inject the steam predominantly from the nozzles  57  arranged in an approximately lateral position, thus avoiding injection in alignment with the direction of the falling stream of tobacco, designated by the reference numeral  63 . 
   To prevent the alteration of the falling motion that this would entail, it is therefore convenient to prevent the injection of steam into the falling stream  63  by the feeder means  56  that are arranged proximate to the tobacco release region, designated by the reference numeral  64 , and optionally also of the feeder means that are arranged in the diametrically opposite position, termed fall region  64   b.    
   One embodiment of the means for temporarily and selectively deactivating the steam feeder means  56  consists in providing, along the tubes  61 , flow control valves, designated by the reference numeral  65  in  FIG. 5 , which can be activated conveniently by way of means adapted to temporarily interrupt the outflow of steam, such as for example a mechanical cam-based actuation system. 
   In particular, at valves  65 , externally to the frame  52 , an annular cam  66  is provided, which is rotatably associated perimetrically with the frame  52  and has a radially arranged raised portion. 
   The annular cam  66 , by acting on a roller, designated by the reference numeral  67 , that is mounted on the moving part of the valve  65 , causes the closure of such valves at the release region  64   a  and at the fall region  64   b , or in any case in the regions where the injection of steam is not required. 
   The tubes  61  for feeding water or steam can be connected to the nozzles  57  according to schemes that are different from the one described above, depending on the most convenient functional model. 
   The feeding of the tubes  61 , during the rotation of the machine  51 , is ensured by a rotary connector, designated by the reference numeral  68 , which is preferably arranged along the rotation axis of the frame  52 , for example proximate to the output region  53   b.    
   The arrangement of the rods  55  can be the most appropriate according to requirements; such arrangement can provide, for example, for an alignment thereof along multiple straight lines or along helical generatrices. 
   In the particular illustrated arrangement, a particularly simple feeding system for the feeder means  56  has been chosen in which each row of rods  55  is fed by a single tube  61  arranged outside the frame  52 . 
   Operation is therefore as follows: as shown in  FIGS. 5 to 7 , the tobacco bales and slices, conveniently shredded into leaves and strips of intermediate product  54 , are lifted by the rods  55  up to the fall region  64   b.    
   During the fall, the falling stream of tobacco  63  forms and is struck by the steam or optionally by the water that exits from the feeder means  56 . 
   Such spraying occurs predominantly on the two sides of the falling stream  63 , not from above or below, thanks to the presence of the deactivation means, which are constituted by the annular cam  66  and by the valves  65  in the illustrated embodiment. 
   It has thus been observed that the present invention has achieved the intended aim and objects, a tobacco processing machine having been devised which allows to provide optimum humidification and/or effective heating of the intermediate product uniformly along the entire length of the cylindrical frame, independently of the density or lightness of said intermediate product. 
   The invention further allows to differentiate the amount of steam or water injected in the different parts of the length of the cylinder, so as to allow to control the shape of the temperature curve and divide the cylinder into a plurality of regions. 
   This differentiation can be achieved easily by means of a chosen connection of the rods to the feeder tubes, or in another manner by adapting the dimensions of the injection nozzles to specific requirements. 
   The injection of the steam along the falling stream of tobacco further occurs on both sides thereof, with a consequent great improvement in the efficiency of the machine and in the quality and uniformity of the output intermediate product. 
   Finally, the cleaning steps at the end of the production cycle are more simple and rapid, since it is possible to use the rods to inject the cleaning water. 
   The invention is of course susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. 
   Thus, for example, it is possible to feed the steam feeder means by way of tubes  61  formed monolithically with the wall of the frame  52 , by means of conventional construction technologies, such as so-called double-skin cylinders. 
   It is also possible to provide for an arrangement of said rods in which said rods are more densely packed at one or more preset regions or to provided, even more advantageously, for a different distribution of the flow-rate of steam or water emitted by said rods, so as to perform a chosen treatment for said tobacco. 
   The materials employed, as well as the dimensions that constitute the individual components of the present invention, may of course be the more pertinent according to specific requirements. 
   The disclosures in Italian Patent Application No. TV2001A000086 from which this application claims priority are incorporated herein by reference.