Abstract:
A method for reducing noise level in a tobacco-processing production machine that is acted upon by flowing process air includes supplying process air to the production machine predominantly conveyed by sound-damping line segments.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Priority is claimed with respect to application No. EP 19943319.4 filed in the European Patent Office on Sep. 10, 1999, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to an arrangement for reducing the noise level of tobacco-processing production machines acted upon by flowing process air, particularly in the operator region of a production line comprising at least two production machines disposed at an angle to one another. 
     Production machines of the tobacco-processing industry primarily encompass cigarette-production machines and filter-attachment machines, which are preferably joined diagonally at a 90° angle to form a production line. The machines may further include packaging machines and other standard tobacco-industry components, such as filter-production machines and article-transport devices, the latter representing a secondary source of noise. Particularly in the aforementioned production line, an operator, who is preferably positioned in the corner zone between two machines, is exposed to a great deal of machine noise. Previous efforts to reduce the noise have been unsuccessful in preventing operating noises created by mechanical components, and flow noises produced by process air, especially suction noises, from being emitted from the machines and entering the operator region, because it is not possible to hermetically seal the machine. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to implement further, more effective anti-noise measures in tobacco-processing production machine. 
     According to the invention, this object is accomplished in that the process air supplied to the production machines is predominantly conveyed via sound-damping line segments. 
     In accordance with a preferred modification, such sound-damping line segments are concentrated in a floor region of the production machines. 
     In accordance with an advantageous modification, the damping measures in the floor region can be particularly effectively supported by the integration of a sound-absorbing floor covering, which is under the production machines, into the sound-damping line segments. 
     To optimize the anti-noise measures, it is further proposed to provide secondary air-flow gaps as noise dampers between moving or stationary machine or wall sections. 
     In accordance with advantageous modifications, the flow noises are additionally suppressed by damping mats that form a cladding of the production machines for sound-damping the air-flow gaps. 
     As a further noise-reduction measure, it is proposed to provide sound-damped air-exit openings on the top of the production machines, so the emitted noise is directed away from the nearby operator region. 
     The advantage attained with the invention is that, in machines whose noise level is distinguished by a relatively large process-air throughput, such as strand machines and filter-attachment machines having conveying air, including retaining air and control blast air, the flow noises are absorbed, and thus rendered harmless to operating personnel at the locations where the noise is the most intense and has the greatest impact on the operator region, namely in the boundary zone between the surroundings and the machine interior. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in detail below in conjunction with embodiments illustrated in the drawing. 
     Shown are in: 
     FIG. 1 is a sectional representation through the distributor of a cigarette-strand machine; 
     FIG. 2 is a sectional representation through a filter-attachment machine; 
     FIG. 3 is a plan view of an angular production line formed by a cigarette machine and a filter-attachment machine; 
     FIG. 4 a floor plan for sound-damping material for setting up the production line according to FIG. 3; 
     FIG. 5 a cross section through a tile element of the sound-damping material according to FIG. 4; 
     FIG. 6 a plan view of the tile element according to FIG. 5; 
     FIG. 7 a cross section through a sound-damping element of the machine cladding; 
     FIG. 8 a plan view of the sound-damping element according to FIG. 7; 
     FIG. 9 an alternative damping cladding on a machine wall embodied as a removable carriage according to FIGS. 1 and 2; 
     FIG. 10 a cross section through a corner profile strip of the carriage according to FIG. 9; 
     FIG. 11 a cross section through an alternative damping profile on a machine cladding embodied as a door; 
     FIG. 12 a front view of the door according to FIG. 11; 
     FIG. 13 a cross section through a detail of the door damping profile; 
     FIG. 14 a cross section through a damping profile of a machine cladding embodied as a see-through flap; 
     FIG. 15 a cross section through an alternative damping tile for covering the floor; 
     FIG. 16 a plan view of the damping tile according to FIG. 15; and 
     FIG. 17 a partial cross section through a further embodiment of the damping tile. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The distributor  1  illustrated in FIG. 1 is an aggregate of the cigarette-strand machine  2  according to FIG. 3, with a high throughput of flowing process air for the purpose of feeding and sorting tobacco and forming a tobacco strand from a stream of tobacco. The tobacco is fed in portions, via a pneumatic lock system  3 , into a reservoir container  4  of distributor  1 , transferred via a screen roller  6  into an intermediate storage element  7 , then transported upward by a removal conveyor  8  equipped with carriers, and placed in a storage shaft  9 , whose fullness level is kept essentially constant. 
     A removal roller  11  continuously removes tobacco from storage shaft  9  and, in cooperation with a beater roller  12 , transfers it into a drop shaft  13 . 
     At the lower exit of the drop shaft  13 , a transverse sorting air current generated by high-pressure air nozzles  14  separates the tobacco into heavier and lighter tobacco fibers, of which the latter are transported to a concave guiding surface  16 , while the former travel downward via a star-feeder lock  17  into a sorting shaft  18 , from which heavy strands are removed at the bottom after a further sorting, and lighter tobacco fibers are transported upward due to the injector effect of a compressed-air jet generated by a further nozzle arrangement  19 , then join the other tobacco fibers on the guide surface  16  to form a tobacco stream that extends over the width of the distributor  1  (perpendicular to the drawing plane), which is supported and accelerated by additional compressed air exiting a further nozzle arrangement  21  at the guide surface  16 . 
     In this way, the tobacco stream is transferred upward to a suction strand conveyor  25  that is moved perpendicular to the drawing plane, and at which a tobacco strand is formed with the use of flowing suction air; this strand is encased and processed into individual cigarettes as it continues through the cigarette-strand machine  2 . 
     The high air throughput effected by the numerous pneumatic conveyor elements creates an increased noise level in addition to the mechanical drive noises of the machine. This noise reaches the outside by way of unavoidable machine cladding gaps. 
     In accordance with the invention, the outside machine walls, flaps, doors, hoods or carriages facing the operating space or the floor region, and acting as reflection surfaces, are provided to the greatest possible extent with noise-damping material in the form of damping mats  22 , which are embodied with a neutral shape, such as frustoconical damping elements  23 , in the region of the outside machine walls according to FIG. 7, and are connected by a central screw connection  24  to the machine cladding sheets of varying sizes so as to be easily exchanged. 
     According to FIG. 7, the damping elements  23  facing the operating space with their sound-damping structure are covered on all absorption surfaces with sound-permeable cladding sheets  26 , which are provided with holes in the manner of a sieve. 
     The damping mats  22  on the machine floor are embodied to limit an air-intake opening  27  of sufficiently-large dimensions, and act as sound dampers  28  on the air  29  flowing in. In this way, the supply of process air is predominantly concentrated over the machine floor, instead of being conveyed via gaps in the front or rear machine cladding. 
     In the filter-attachment machine  30  shown in FIG. 2, which is likewise operated with a high air throughput for retaining rod-shaped tobacco articles in the cavities of conveyor drums  31 , and for checking and separating out articles, damping mats  22  embodied in the same manner are mounted to the front and rear machine cladding, and on the machine floor, in the form of a sound damper  28  for a central air-intake opening  27 . 
     In addition, a damping mat  22  is laid on the floor, at least from the standing region in front of the machine to beneath the machine floor. 
     In the cigarette-strand machine  2  and filter-attachment machine  30  having a switch cabinet  32 , and with the machines being set up at a closed right angle to form a production line  35  according to FIG. 3, the damping mat  22  is designed to cover the entire base surface of the production line  35  corresponding to FIG.  4 . As the floor mat, the damping mat  22  comprises individual damping tiles  33 , which, according to FIG. 5, are embodied as tile boxes  34  having supports  36  that are disposed in the manner of a grid, and are equipped with damping material in the form of damping mats  22  inserted with a precise fit. The tile boxes  34  as the standing surface are provided with a gridiron support  37  that is screwed to the supports  36 . 
     Corresponding to the setup plan of the production line  35 , stress-specific supports are inserted into the gridiron supports  37  according to FIG. 4, for example, at the locations with greater particle accumulation, in the form of easy-to-clean, closed plates  38 , or under the machine bases in the form of reinforced support plates  39 . 
     As a further anti-noise measure, according to FIG. 2, the remaining gaps  41  at the machines  2  and  30  are embodied to have the greatest possible sound-damping effect. 
     The air sucked in through a fan  42  is conveyed through sound-damped flow conduits  43 ,  44 ,  46  inside the machine, and carried off via an air exit  47  at the top of the machine, which further reinforces the sound damping. 
     In alternative embodiments of the damping elements illustrated in FIGS. 9 through 16, parts that correspond to those in the above-described arrangements are provided with reference numerals that are increased by one hundred. 
     In the carriages  148  illustrated on the outside of the machine in FIGS. 9 and 10, damping mats  122  are inserted laterally and underneath between inside reflection surfaces  120  and outside, sound-permeable cladding sheets  126 , and into corner-profile strips  149 , with the plate-shaped reflection surfaces  120  and cladding sheets  126  being inserted into the correspondingly-spaced receiving grooves of corner-profile strips  149 . 
     In the machine cladding embodied as a door  151  in FIGS. 11 through 13, inside and outside sound-permeable cladding sheets  126  with interposed reflection surfaces  120  are inserted into receiving grooves of four profile strips  154  joined by corner connectors  152  to form a profile frame  153 . The hollow spaces formed in the process are filled with damping mats  122 . 
     Sealing elements  157  are inserted into the profile frame  153 , which can pivot about an axis  156 . The cladding sheets  126  and the reflection surface  120  are stabilized against shifting by spacing sleeves  158  that are screwed together. 
     In the window flap  159  illustrated in FIG. 14, two viewing panes  162  and  163 , and a cladding sheet  126 , are inserted as a double glazing into a profile strip  161  of a window frame. The cladding sheet limits a hollow space that is filled with damping mats  122 . 
     In the alternative tile box  134  of a damping tile  133  covering the floor, as shown in FIGS. 15 and 16, the gridiron support  137  is provided with elevations  164  in a specific lattice or grid arrangement of the supports  136 ; these elevations prevent tobacco fibers that are lying on the gridiron support  137  from entering the damping mats  122 , and allows them to be swept away more easily. 
     Furthermore, buffers  166 , which prevent a solid-borne sound transmission between the damping tiles, and into the floor, are inserted, on the side and bottom, between the damping tiles  133 . 
     As the last embodiment, in a floor-damping tile  233 , a gridiron support  237  is provided with rounded edges  267  and a sound-permeable film  269 , which is inserted between a narrow-mesh sieve  268  that lies on the damping mat  222  and the gridiron support  237 , the film preventing the passage of fine particles into the damping material. 
     The invention has been described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.