Abstract:
An apparatus and a method for drying articles are disclosed. The apparatus includes a closed housing with at least one chamber equipped with air nozzles. The apparatus has an inlet opening and an outlet opening for the articles to be dried. An inner routing of air flow inside the housing generates a defined removal of air to the at least one air outlet opening. The inner routing of air flow is designed such that a flow of air is directed past the inlet opening and/or the outlet opening for the articles to be dried.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of German Patent Application No. 10 2008 004 774.0, filed on Jan. 16, 2008, which application is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to an apparatus for drying containers for beverages. In addition, the invention relates to a method for drying containers for beverages. 
       BACKGROUND OF THE INVENTION 
       [0003]    Normally, certain humidity prevails with apparatuses for filling and labelling of bottles, and the humidity adheres to the exterior surface of the bottles after the filling process. Traces of liquid can also remain on the interior surface and/or exterior surface of the bottles after the bottles had been washed. 
         [0004]    During optical inspection of the bottles for mechanic intactness and/or the existence of foreign particles, such as impurities or bits of broken glass for example, such remaining traces of liquid in the form of drops can considerably limit the optical image quality. Therefore it is advantageous to subject bottles for optical inspection which are as dry as possible. 
         [0005]    Apparatuses for drying bottles, as known from the state of the art, comprise one or more consecutively arranged box-shaped chambers, whereby a conveyor belt with upright standing bottles is routed through. Inside the chamber, a plurality of air nozzles are blowing off remaining liquid adhering to the exterior surface of the bottles and guarantee thereby that dry bottles are leaving the apparatus for drying articles. The amount of air needed for drying is provided by a high-capacity blower which intakes outer air and routes it to the nozzles. Excess pressure prevailing within the particular chambers of the apparatus for drying articles can exhaust by means of a plurality of openings, particularly through the opening for the bottle supply and the opening for the bottle removal which are defined by the position of the conveyor belt. Since a significant amount of air is required for feeding the air nozzles, excess pressure exhausts with relatively high air speed. The exhausting air and the fast-running blower cause a significant generation of noise. 
       SUMMARY OF THE INVENTION 
       [0006]    The object of the invention is to reduce the acoustic emissions produced by an apparatus for drying articles such as containers for beverages and bottles. 
         [0007]    This object of the invention is achieved by an apparatus for drying articles. The invention is particularly designed as an apparatus for drying articles, wherein the articles are bottles. The apparatus comprises a largely closed housing with at least one chamber. For drying the articles and bottles respectively, the articles or bottles are being transported on a conveyor belt through the housing and subjected to compressed air and rapid accelerated air respectively within the housing. Inlet openings and outlet openings are provided for the conveyor belt with the bottles or other articles to be transported on it. Furthermore, at least one air inlet opening for the supply of drying air and at least one air outlet opening for discharging the drying air out of the housing are provided. According to the present invention, an inner routing of air flow inside the housing is formed for generating a defined removal of air to the at least one air outlet opening. The inner routing of air flow has a flow which is directed past the inlet opening and/or the outlet opening for the articles to be dried. The directed air flow provides that as little air as possible leaks through the inlet opening and the outlet opening, so that in this way the airborne sound, which is transported through the inlet opening and the outlet opening, is being reduced considerably. 
         [0008]    Another object of the invention is to provide a method which reduces the acoustic emissions produced by an apparatus for drying articles such as containers for beverages and bottles. 
         [0009]    The method for drying articles, particularly containers of beverages such as bottles or the like, provides air nozzles which are blowing at the articles to be dried inside of a largely closed housing. Drying air is being supplied via at least one air inlet opening and the air is being discharged again via at least one air outlet opening out of the housing. According to the present invention, a defined removal of air to the at least one air outlet opening is generated by means of an inner routing of air flow inside the housing, wherein the exhaust air is basically directed past an inlet opening and/or outlet opening for the articles to be dried. In this way it is avoided that air from the inlet openings and outlet openings for conveying the articles is discharged uncontrolled through the housing, and that thereby all sound absorbing features are considerably facilitated due to the immediate influence on the relevant sound sources. According to a preferred embodiment of the method according to the invention, the exhaust air is routed through at least one outlet opening being formed as a sound absorbing air discharge duct. 
         [0010]    According to a preferred embodiment of the invention, the at least one air outlet opening is formed as an air discharge duct, through which the air of the blower is being discharged. When the air discharge duct is formed in such a way, well directed sound absorbing features can be intended for. Furthermore, effective sound absorption can be realised with relatively low constructional effort. As a result, the air discharge duct can be particularly formed as a reflexion and/or as an absorption silencer. For this purpose, sound absorbing elements can be arranged in the air discharge duct. The absorbing elements can be basically almost any embodiments, as known and available in the field of machine acoustics. The arrangement of at least one structured plate with metal wool as an absorbing element, wherein the structured plate is arranged inclined to the longitudinal direction, could be particularly simple and inexpensive. Alternatively, two or more suchlike structured plates, which are arranged inclined to the longitudinal direction, can be arranged consecutively in the air discharge duct. The sound is being partially absorbed and partially reflected at this structured plates, wherein the sound is being scattered excessively. 
         [0011]    The sound absorption can be supported by means of lining the inner walls of the air discharge duct with sound absorbing material and/or providing structured inner walls of the air discharge duct. As for structured plates, mesh surfaces with large mesh sizes with metal wool or mineral wool being arranged behind the mesh surfaces can be used, for example. Stainless steel wool is particularly suitable as sound absorbing material, since no nameable corrosion occurs, so that also high hygienic requirements are fulfilled during permanent operation. 
         [0012]    The air flow running through the air discharge duct can be supported by means of additional fans which optionally either blow or exhaust. It is an advantageous embodiment to provide an sucking fan at the outer mouth of the air discharge duct which can additionally support the defined routing of air flow within the housing by means of its undertow effect. 
         [0013]    According to another embodiment of the present invention, blowing nozzles which are geared to the air discharge duct can be arranged within the housing near by the inlet opening and/or the outlet opening for the articles to be dried. These blowing nozzles can be directed inclined upwards on both sides of the conveyor belt. Preferably, the blowing nozzles are arranged nearby and underneath the air discharge duct respectively, so that the air flow running through the housing and in direction of the air discharge duct is predetermined by the airflow of these nozzles as well as by the undertow being generated by the additional fan as the case may be. Ideally, only a very small portion of drying air is being discharged from the inlet openings and the outlet openings when using the above-mentioned arrangement, so that the effort regarding sound absorbing features can be kept low at these positions. 
         [0014]    In addition, the housing can be provided with elements for air sound absorption and/or body sound absorption, for example in the shape of insulating mats at the interior surfaces of the housing. Preferably, all openings of the housing which are not necessary for the air flow, such as clearances at flaps or lids, are sealed. The additional insulating mats can both reduce body sound oscillation and provide the sound radiation of the housing surfaces being reduced. 
         [0015]    A particularly advantageous embodiment of the apparatus according to the invention is a modular assembly having a plurality of consecutively arranged drying modules, which are connected with each other. The smallest unit is formed by one single module having an inlet opening as well as an outlet opening for the articles to be dried, such as bottles. Within the housing, at least one air nozzle arrangement is provided for blowing off the articles. Besides, an air supply and an air discharge opening are necessary. Alternatively, a plurality of further modules, having different or identical air nozzle arrangements and apart from that a largely same assembly, can be connected with this one single module. 
         [0016]    In this way, a first drying module with the inlet opening for the articles and bottles respectively and with nozzles for a drying of a lateral area of the articles and/or of a bottle neck can be provided. A second drying module being connected with foresaid first drying module in feeding direction of the articles can be provided, for example, with nozzles for drying the bottom of the articles and/or the bottom of the bottle. A third drying module being connected with the foresaid second drying module in feeding direction of the articles can be provided both with the outlet opening for the articles to be dried and with further nozzles for drying the lateral area and/or the bottle neck. As a matter of course, apparatuses with only two drying modules or also with four drying modules or more drying modules are possible depending on the drying effort which is necessary and reasonable in the particular application. 
         [0017]    As for hygienic requirements during the filling process and as for the permanent humid atmosphere, it is reasonable if the elements of the apparatus for drying articles are basically of corrosion-resistant material. For this purpose, stainless steel is particularly suitable. Alternatively, non-metallic elements can also be used. 
         [0018]    A preferred embodiment of the invention provides at least one air flow generator which is formed by means of a blower being arranged inside the housing or at the housing. Such blower can be provided with particularly one electric driving motor and an axial conveyor or radial conveyor, which is preferably provided with an air intake filter and/or an intake silencer. If necessary, the power of the blower can be adjusted variably. In order to balance the losses caused by an air intake filter, which is no longer fully transmissible, it can be reasonable to detect the decrease of pressure caused by the decreasing filter transmissibility by means of a suitable sensor in the air feed pipe after the blower and to balance the decreasing transmissibility by means of an increased power of the blower. As soon as the power of the blower reaches a maximal value after having been running for a long time, the necessity of changing or cleaning the air intake filter can be displayed. 
         [0019]    Alternatively, the air flow generator can be arranged separately from the apparatus for drying articles and be connected with the apparatus for drying articles via an air feed pipe. This can be then of advantage, when a central air supply for a plurality of modules or a plurality of apparatuses for drying articles can be reverted to. This alternative, however, can also be advantageous regarding an even better noise reduction, since with all sound insulating features the sound proportions of the blower and its driving motor as well as of the intake noise do not have to be taken into consideration anymore. Basically, only the noise development of the air emanating from the drying nozzles as well as the airborne sound of the air being discharging from the housing is to be taken into consideration. 
         [0020]    Further sound absorption can be achieved by positioning the outlet air silencer separately from the housing and connecting the outlet air silencer with the housing via an air outlet feed pipe. 
         [0021]    In another embodiment of the method, the blowing nozzles, which are positioned within the housing near by the inlet opening and the outlet opening for the articles, can provide exhaust air to be geared to the air discharge duct. The air flow is preferably being generated by means of a blower which is positioned either inside the housing or at the housing. 
         [0022]    Alternatively, the drying air can be supplied, however, also from the outside via an air feed pipe. 
         [0023]    Another embodiment of the method comprises the step of detecting a delivery pressure or a delivery volume within the air feed pipe after the blower. In this way, a varying delivery pressure of the blower can be counteracted by adjusting the power of the blower. The delivery pressure can, for example, decrease due to a decreasing transmissibility of the increasingly clogged air intake filter. By increasing the rotational speed of the blower motor, the capacity of the blower can be kept constant as long as the maximal output of the driving motor is reached. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Further features, objects and advantages of the present invention will now be explained in greater detail in the following description which should not be regarded as limiting the invention and which refers to the accompanying figures. Same reference numbers refer to same elements throughout the various figures and are not explained repeatedly. 
           [0025]      FIG. 1  shows a perspective view of an apparatus for drying articles consisting of three drying modules connected with each other. 
           [0026]      FIG. 2  shows a perspective cutted view along the longitudinal axes of the apparatus for drying articles according to  FIG. 1 . 
           [0027]      FIG. 3  shows a detailed view of a first drying module of the apparatus for drying articles. 
           [0028]      FIG. 4  shows an air discharge duct of the drying module, whereby the air discharge duct is formed as a sound silencer. 
           [0029]      FIG. 5  shows a top view on the air discharge duct. 
           [0030]      FIG. 6  shows the direction of the air flow within a drying module. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    The schematic view of  FIG. 1  shows a perspective view of an apparatus  12  for drying articles consisting of three drying modules  10  connected with each other, which can serve in the present embodiment particularly for drying bottles after they had been filled and capped. The drying modules  10  form a common housing  14  of the apparatus  12  for drying articles, since the walls are missing on their sides pointing to each other. A conveyor belt  16  runs through the apparatus  12  for drying articles, and upright standing bottles are being transported onto the conveyor belt  16  through the apparatus  12  for drying articles. For this purpose, the first drying module  10   a  is provided with an inlet opening  18  for the conveyor belt  16  with the bottles, which are arranged on the side wall remote from the second drying module  10   b . In the same way, the third drying module  10   c  is provided with an outlet opening  20  for the conveyor belt  16 , whereby the outlet opening  20  is also arranged on the side wall remote from the second drying module  10   b . Both the inlet opening  18  and the outlet opening  20  are formed as attached air locks  22  which provide by means of their interior assembly that only little air can leak from the inside of the housing of the apparatus  12  for drying articles through the openings  18  and  20 . In addition, this function as an air lock  22  as well as the sound absorbing design of the air locks  22  provides that only very slight noise emissions emanate from the openings  18  and  20 . The remaining walls  24  of the drying modules  10  are of firmly assembled and pivoted plates which can be preferably lined on the inside with sound absorbing material such as bitumen mats or the like. The front walls  24  can particularly be formed as pivoting doors, through which the inside of the housing can be quickly accessed. 
         [0032]    The upper part of the housing of each drying module  10  is formed as an air flow generator having an air inlet opening  26  positioned at an upper side wall and air outlet openings  28  positioned at the top of the housing. The in-coming drying air from the inlet opening  26  is being routed to the drying nozzles nearby the conveyor belt  16  with the bottles standing upright on it by means of an electromotive blower (see  FIG. 2 ) and air feed pipes, and being routed again to the outside through the outlet openings  28 . 
         [0033]    The schematic view of  FIG. 2  shows a perspective longitudinal cut of the apparatus  12  for drying articles for drying bottles  30  which are being transported on the conveyor belt  16 . Hereby it is recognisable that each of the shown drying modules  10   a ,  10   b  and  10   c  is basically provided with three housing segments. In the middle housing segment, the conveyor belt  16  as well as the nozzles (see  FIG. 3 ) for blowing off the bottles  30  are situated. A funnel shaped or tray shaped water outflow as well as, if necessary, a siphon for sound insulation at the deepest position of the middle housing segment are provided on the bottom. The dripping and/or draining water from the bottles or from other parts of the drying module  10  are being here gathered and carried off. 
         [0034]    The air inlet opening  26 , an air flow generator as well as an air discharge duct  36  which is routed to the air outlet opening  28  are positioned above the middle segment and separated by a horizontal separating plate  32 . The air discharge duct  36  having the form of a sound silencer is being described in more detail on the basis of  FIGS. 4 and 5 . 
         [0035]    The detailed view of  FIG. 3  shows the first drying module  10   a  of the apparatus for drying articles  12  with its substantial elements. The tray  38  which is positioned underneath the conveyor belt  16  gathers the water and carries off the water if necessary via a sound absorbing labyrinth pipe (not shown) and a siphon respectively. Directly past the inlet opening  18  and the air lock  22  shielding the inlet opening  18 , a first air nozzle arrangement  40  is positioned in the shape of four pairs of circular nozzles inclined upwards which are directed onto the bottle  30  neck part and are upwards blowing off the bottles  30 . The circular nozzles of the first air nozzle arrangement  40  are each on both sides positioned on the conveyor belt  16 . Preferably, both the distance between the circular nozzles and the conveyor belt  16 , and the vertical position of the circular nozzles and/or the blowing angle can be varied in order to allow different widths of the conveyor belt  16  and likewise different sizes, i.e. different bottle widths and bottle heights. Past the first air nozzle arrangement  40  a second air nozzle arrangement  42  follows in the shape of gradually arranged flat extrusion nozzles which are consecutively arranged among each other in the feeding direction of the bottles  30 . Two of those discharging areas are arranged opposing to each other on both sides of the conveyor belt  16 . The second air nozzle arrangement  42  is also preferably adjustable in its respective distance to the conveyor belt  16  as well as in its incline and/or height if necessary. 
         [0036]    Both air nozzle arrangements  40  and  42  are being fed via air feed pipes  44  from the air flow generator  34  which is positioned above the horizontal separating plate  32 , whereby the air flow generator  34  comprises an axial blower  46  as well as an electric driving motor  48  for the drive of the blower  46  in the embodiment shown. Alternatively, a radial blower or another suitable design can also be used. The driving motor  48  can optionally be connected with the blower  46  via a drive belt or a gear or via a direct axial connection. As recognisable from  FIG. 2 , an air intake filter  50  is arranged upstream of the blower  46 , whereby the air intake filter  50  filters the intaked air and can serve as an intake silencer or being connected with an additional intake silencer if necessary. Within the air feed pipe  44  close to the blower  46  a sensor (not shown) is arranged. The sensor measures the pressure difference between the surrounding area and the excess pressure existing inside the air feed pipe  44  and sends an output signal to a control unit for the driving motor  48 . By using such a control unit, even with a decreasing transmissibility of the air intake filter  50 , the resulting power of the blower  46  can be kept constant at least as long as the driving motor  48  reaches its capacity by increasing the rotational speed. 
         [0037]    The air flow generator  34  is separated from the air discharge duct  36  by a vertical separating plate  52 , whereby the air discharge duct  36  is provided with a lower opening  54  which breaks through the horizontal separating plate  32  and which provides an open air compound to the middle segment with the drying nozzles  40 ,  42 . 
         [0038]    The longitudinal embodiment of  FIG. 4  shows the air discharge duct  36  of the drying module  10 , whereby the air discharge duct  36  is formed as a sound silencer. On two vertical side walls  56  of the air discharge duct  36 , which are opposing each other, sound absorbing elements  58  are arranged, which are provided by structured plates  60  inclined to the longitudinal direction of the air discharge duct  36 . In the embodiment shown, the plates  60  have coarse metal lattices  62  and an infill  64  with metal wool. The sound absorbing effect results for this reason both from a reflexion damping by redirecting the discharging air and an absorption damping by the metal wool. If necessary, the inner walls of the air discharge duct  36  can have additionally a structured surface and/or be lined with sound absorbing material. 
         [0039]    In a cover plate  66  of the air discharge duct  36 , an additional air discharge is provided, for example, by one or two suction blowers  68 . The top view of  FIG. 5  shows an embodiment of the air discharge duct  36 , which is provided with two suction blowers  68 . 
         [0040]    As clarified on the basis of  FIGS. 1 to 3 , the drying modules  10  of the apparatus  12  for drying articles can alternatively be supported on the bottom via vertical supports  70  as well as via height adjustable bases  72  if necessary. The supports  70  form advantageously a supporting frame, which is stabilized by means of crossbars with which the side walls are held. As a matter of course, the housings  14  of the drying modules  10  can be designed in a different way as shown. As clarified on the basis of  FIG. 2 , the largely similar assembled drying modules  10  can be provided with different air nozzle arrangements  40 . In this way, the second drying module  10   b  comprises a third air nozzle arrangement  74 , which blows off the bottles  30  from the bottom. The third drying module  10   c  is provided with a fourth air nozzle arrangement  76  as well as with a fifth air nozzle arrangement  78 . While the fifth air nozzle arrangement  78  corresponds in assembly and its positioning nearby the outlet opening  20  for the conveyor belt  16  and the bottles  30  with the first air nozzle arrangement  40 , the fourth air nozzle arrangement  76 , which is running inclined upwards and having narrow air nozzles, is provided for blowing off the bottles  30  from the bottom up. On the other hand, an air lock  22  is arranged at the outlet opening  20  (see  FIG. 1 ). 
         [0041]    The schematic view of  FIG. 6  shows the direction of the air flow within one drying module  10 , which describes a circular flow in direction to the air discharge duct  36  starting from the blower  46  via the air feed pipe  44  and the second air nozzle arrangement  42 . The redirection of the flow upwards in direction of the air discharge duct  36  is being benefited on the one hand by the exhausting air at the first air nozzle arrangement  40 . 
         [0042]    Since the first air nozzle arrangement  40  is arranged directly underneath the air discharge duct  36  and since the air of the nozzles is running out inclined upwards, the discharged air from the second nozzle arrangement  42 , too, is being routed in the area above the conveyor belt  16  to the left in direction to the first air nozzle arrangement  40  and from there upwards in direction to the air discharge duct  36 . The described air flow is additionally supported by the sucking blower  68  which is arranged at the air outlet of the air discharge duct  36  and which transports the humid outlet air upwards out of the housing of the apparatus  12  for drying articles. In the embodiment of  FIG. 6 , the reference number  80  refers to the drying air being transported by the blower  46  through the air feed pipe to the air nozzle arrangements  40 ,  42 , while reference number  82  refers to the humid outlet air being transported through the air discharge duct  36 . The shown direction of the air flow provides that only a very little portion of the humid outlet air  82  leaks through the inlet opening  18  or through the outlet opening  20 . The sound absorption is optimized thereby that the predominant portion of the humid outlet air  82  is being discharged to the outside through the air discharge duct  36  which is formed as a sound silencer. 
         [0043]    The present invention has been described with respect to preferred embodiments. It is conceivable for a skilled person to carry out amendments or changes of the present invention without departing from the scope of the claims below.