Abstract:
System for allowing removal of air from the interior of flexible packages, in which material can be found, including a conveyor transporting and supporting the bottom of the flexible packages or package, a second sub-system holding the top part of the package and an air extraction system. The package is raised vertically while being displaced along the conveyor. Removing the air from the packages before closing them results in a flat and straight flap, while reducing the distance between the product and the sealed or sewn joint. The process is accomplished through a continuous displacement of the package. These advantages result in packing material savings. A method for allowing removal of air is also disclosed.

Description:
RELATED APPLICATIONS 
       [0001]    This application is the U.S. National Phase under 35 U.S.C. §371 of International Application No. PCT/CA2009/000785, filed on Jun. 4, 2009, which in turn claims the benefit of U.S. Provisional Application No. 61/058,805, filed on Jun. 4, 2008, the disclosures of which Applications are incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to packaging systems. More particularly, the present invention relates to a deaeration system for flexible packages and a method associated thereto. 
       BACKGROUND OF THE INVENTION 
       [0003]    Several different types of products are packaged typically in flexible packages. After filling of the packages, in order to reduce the overall volume of the package; it is often desired to remove air remaining within the package before sealing thereof. Removing the air from the packages before closing them results in a flat and straight flap (upper part of the package above the product). Then, it is possible for the closing system belts to be closer to the product. Therefore, it is possible to reduce the distance between the product and the sealed or sewn joint. By reducing this distance, the freeboard (distance between the upper part of the package and the product level when the package is full) is also reduced. The required length of empty bags is consequently reduced, which result in packing material savings (economic and ecological savings). 
         [0004]    The invention described in U.S. Pat. No. 7,316,102 involves an apparatus for extracting air from within flexible packages. The package is displaced along a conveyor system and has air removed therefrom under a hood which is linked to a subsequent closing mechanism. 
         [0005]    However, flexible packaging customers still have several requirements that are not completely satisfied with existing deaeration systems, including:
       Reducing a warehouse bursting packages problem;   Reducing the amount of air in packages;   Maintaining current productivity, reliability and quality;   Using the smallest footprint possible (ex.: providing 7 feet maximum length available for the footprint);   Providing flexible package sizes (from 13″ to 20″); and   Using less freeboard.       
 
         [0012]    Consequently, there is still presently a need for a deaeration system and associated method which offers superior results in terms of the efficiency of the removal of air from the flexible package and addresses the above requirements. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention addresses at least one of the above-mentioned needs. 
         [0014]    More particularly, the present invention provides a system for removal of air from an interior of a flexible package before closure thereof, the system comprising:
       a lower conveyor sub-system for continuously displacing the package along a length of the system;   an upper driving sub-system holding continuously an upper part of the package, keeping the upper part closed along a length of its displacement, said upper driving sub-system comprising at least one perforated belt bag-opening sub-system comprising:
           at least one pair of adjacent guiding structures, each guiding structure having a profile surface facing a corresponding profile surface of the opposite guiding structure;   a plurality of driving belts, each belt circulating around a corresponding guiding structure of the at least one pair of guiding structures, each of said belts following a path along the corresponding profile of the guiding structure on which the driving belt is travelling;   a pulley system for driving displacement of the plurality of driving belts around the guiding structures; and   a belt sub-system vacuum source applying vacuum behind the belts, said at least one bag-opening sub-system spreading partially open the upper part of the package at a specific location along the length of the system when passing between the profile surfaces of adjacent guiding structures, said upper driving sub-system being synchronized with the lower conveyor sub-system;   
           and
           a deaeration port located above the bag-opening sub-system allowing removal of air from the interior of the package when the package is positioned under the port.   
               
 
         [0023]    Preferably, the lower conveyor sub-system has a profile or shape that allows the package to increase in height sufficiently to remove vertical tension from the top of the package. 
         [0024]    Preferably, the bag-opening sub-system has a shape that allows the upper part of the package to be partially opened by a vacuum source connected to bag-opening sub-system. 
         [0025]    Preferably, the air removal section displaces the package through a perforated belt system or any other equivalent system allowing repositioning of the package and allowing passage of a certain quantity of air. 
         [0026]    Preferably, the air removal section opens a portion (in the upper part) of the package. In this section, the upper sides of the package are maintained against the driving belts to spread it out, partially opening the package. In fact, a source of vacuum applied behind the perforated belts, a pulley desynchronisation and a curved block or guiding structure constrain the two belts to follow a curved path (opposite of one another). 
         [0027]    The present invention also provides a method for removing air from the interior of flexible packages before closure thereof, comprising the following steps:
       a) providing a system for removal of air comprising:
           a lower conveyor sub-system for continuously displacing the package along a length of the system;   an upper driving sub-system holding continuously an upper part of the package, keeping the upper part closed along a length of its displacement, said upper driving sub-system comprising at least one perforated belt bag-opening sub-system comprising:
               at least one pair of adjacent guiding structures, each guiding structure having a profile surface facing a corresponding profile surface of the opposite guiding structure;   a plurality of driving belts, each belt circulating around a corresponding guiding structure of the at least one pair of guiding structures, each of said belts following a path along the corresponding profile of the guiding structure on which the driving belt is travelling;   a pulley system for driving displacement of the plurality of driving belts around the guiding structures;   a belt sub-system vacuum source applying vacuum behind the belts, said at least one bag-opening sub-system spreading partially open the upper part of the package at a specific location along the length of the system when passing between the profile surfaces of adjacent guiding structures, said upper driving sub-system being synchronized with the lower conveyor sub-system;   
               
           and
           a deaeration port located above the bag-opening sub-system allowing removal of air from the interior of the package when the package is positioned under the port,   
           b) displacing continuously the package along a horizontal direction, using the low conveyor sub-system;   c) maintaining continuously an upper part of the package closed along a length of its displacement, using the upper driving sub-system;   d) partially opening the upper part of the package at a specific location along the length of the system, using said bag-opening sub-system; and   e) removing air from the interior of the package when the package is positioned, at said specific location, using the deaeration port.       
 
         [0041]    According to the present invention, there is also provided a system for removing air from an interior of a flexible package before closure thereof, comprising:
       displacement means for continuously displacing the package along a horizontal direction while supporting a bottom of the package and holding an upper part of the package at all times;   raising means for raising the bottom of the package along a distance of travel of the package to reduce vertical tension within the package; and   opening means for opening a portion of the upper part of the package, said opening means comprising:
           at least one pair of guiding structures, each guiding structure having a profile surface facing a corresponding profile surface of the opposite guiding structure;   a plurality of driving belts, each belt circulating around a corresponding guiding structure of the at least one pair of guiding structures, each of said belts following a path along the corresponding profile of the guiding structure on which the driving belt is travelling;   a pulley system for driving displacement of the plurality of driving belts around the guiding structures; and   a belt sub-system vacuum source applying vacuum behind the belts, said bag-opening sub-system spreading partially open the upper part of the package at a specific location along the length of the system when passing between the profile surfaces of adjacent guiding structures, while maintaining displacement of the package;   
           and
           a deaeration port located above the opening means allowing removal of air from the interior of the package when the package is positioned under the port.   
               
 
         [0051]    The system according to the present invention offers the following advantages:
       Capability of staying in control of the top of package   Keeping current packaging machine configuration   Capability of being added at the exit of machine   Capability to remove air “in-line” (continuously) with up to 150 fpm linear speed   Keeping high level of reliability   Preventing air entrance into the package (after air extraction and prior to sealing)   Package shape conditioning after sealing       
 
         [0059]    A non-restrictive description of preferred embodiments of the invention will now be given with reference to the appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0060]      FIG. 1  is a side view of the system according to a preferred embodiment of the present invention; 
           [0061]      FIG. 2  is another side view of the system shown in  FIG. 1  with the packages removed and the upper housing installed; 
           [0062]      FIG. 3  is another side view of the system shown in  FIG. 2  with the upper housing removed; 
           [0063]      FIG. 4  is a another side view of the system according to a preferred embodiment of the present invention; 
           [0064]      FIG. 5  is a side close-up view of the upper driving system shown in  FIG. 4 ; 
           [0065]      FIGS. 6A and 6B  are top and side-cut views respectively of an aluminium block or guiding structure and associated hardware from  FIG. 4 ; 
           [0066]      FIG. 7  is a detailed side view of the upper driving system (air removal section) shown in  FIG. 5 ; 
           [0067]      FIG. 8  is another side close-up view of the upper driving system shown in  FIG. 4 ; 
           [0068]      FIG. 9  is a side view of the system shown in  FIG. 4 , during its operation with packages, illustrating different work stations; 
           [0069]      FIG. 10  is a top view of part of the upper driving system shown in  FIG. 4 ; 
           [0070]      FIGS. 11   a  and  11   b  are front views of the interaction of a package with a system according to another preferred embodiment of the present invention, showing lower and upper positions of the package; 
           [0071]      FIGS. 12   a  to  12   c  are side views of the interaction of a package with a system according to another preferred embodiment of the present invention, as the package travels along the conveyor system; 
           [0072]      FIGS. 13   a  and  13   b  are perspective views of the interaction of a package with the system shown in  FIG. 11 , before and after removal of air; 
           [0073]      FIGS. 14   a  to  14   d  are perspective views of the interaction of a package with the system shown in  FIG. 11 , illustrating air extraction, vacuum shutdown and maintaining of the condition of the package after extraction. 
           [0074]      FIGS. 15A to 15C  are side, top and front views respectively of the system shown in  FIG. 1  with the upper housing and associated support structure installed. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0075]    As shown in  FIGS. 1 to 3  and  15 A to  15 C, a deaeration system  10  for flexible packages  12  according to the present invention is shown. The system comprises a lower conveyor sub-system  14 . The system  10  also has an upper driving system  16  maintaining continuously the upper part of the package  12  closed along a significant length of its displacement. The upper driving system  16  comprises one or several bag-opening sub-systems, preferably connected to a vacuum source  18 , that allows opening of the flexible package at a specific location when the package travels along the upper driving system  16  and on the lower conveyor system  14 . The system also comprises a deaeration port  20  located above the upper driving system  16  connected to the vacuum source  18  that allows removal of air from the interior of the package  12  when the package is positioned under the deaeration port  20  by the upper driving system  16  and the lower conveyor system  14 , under the bag-opening sub-system. 
         [0076]    In the present application, it is to be understood that the deaeration port can be an aspiration port, a dedusting port, a vacuum port, a system connected to a vacuum source or any other equivalent system known to the person of skill in the art which is capable of removing air or substances from the package. 
         [0077]    As better shown in  FIG. 4 , the lower conveyor  14  includes a steel frame  30 , conveyor rollers  32  and a conveyor belt  34 . The conveyor belt is driven by a motor  36  at a constant linear velocity in order to displace the package towards the closing or sealing systems located downstream. The steel frame has a shape  38  that allows the conveyor belt and the package to rise along a certain height while translating along the system. 
         [0078]    As better shown in  FIG. 5 , the system  40  controlling the upper part of the package has three sections,  42 , 44 , 46 . The first  42  and third  46  sections are made of aluminum blocks or guiding structures, pulleys and belts. The upper part of the package is maintained closed through pressure exerted by the belts on the package. The belts are driven by a motor  48  at the same linear velocity as the lower conveyor belt. 
         [0079]    As better shown in  FIGS. 6A and 6B  and  7 , the mid-section of the system  44  includes aluminum blocks or guiding structures  50  having a special shape, perforated belts  52 , pulleys  54  and various other pieces of hardware. On each side of the system, a tube  56  connected to a high debit ventilator removes the air through an opening in the aluminum blocks or guiding structures and through the perforated belt. 
         [0080]    As better shown in  FIG. 8 , the vacuum removal system  18  is a deaeration port  60  located above the upper section. This port is connected to a high flow ventilator  62  for removal of the air. 
         [0081]    Explanation of the Operation of the System 
         [0082]    The package arrives from the packaging system with a certain quantity of air inside thereof, in addition to the packaged product. The product reaches a certain height within the package. The upper part of the package which is not filled is designated as the freeboard. During removal of air from the package, the sides of the freeboard approach one to another. Raising the package using the shape of the bottom conveyor will result in loose freeboard. Once an amount of play (loose) is given to the freeboard, the package enters into the deaeration module. The blocks or guiding structures in the deaeration section have a special internal curvature. The belts are assembled in a manner such that there is a greater length on the side on which the belts face each other to follow the curvature. Moreover, the source of vacuum produced by the high flow ventilator which removes the air from behind the belts constrains the belts to follow the curvature of the block or guiding structure. Finally, as the belts are perforated, a certain quantity of air passes through them so that the upper sides of the package are constrained to follow the belt and curvature of the block or guiding structure. 
         [0083]    In  FIG. 9 , the package can be seen along three different stations along the system. The steps presented below are shown on the figure.
       A. Module receives packages from packaging machine.   B. Bottom of the package is raised prior to vacuum extraction.   C. Top of package is forced to open and air is extracted from package.   D. Package exits towards the sealer.       
 
         [0088]    In  FIG. 10 , the air removal section of the system is seen from above. The two blocks or guiding structures facing each other can be seen, as well as the package along three different positions during its displacement through the system. The package is represented through bold lines and the hash marks represent the opening through which air is removed from the inside of the package. 
         [0089]      FIGS. 11 to 14  illustrate various aspects of the system during operation. 
         [0090]      FIGS. 11   a  and  11   b  show lower and upper positions of the package along the conveyor illustrating how tension is removed from the top of the package once it is lifted. 
         [0091]      FIGS. 12   a  to  12   c  are side views of the package as it travels along the conveyor system. In this example, the slope is 3 inches over 2 feet, preferably at 150 fpm. 
         [0092]      FIGS. 13   a  and  13   b  illustrate the package before and after removal of air. 
         [0093]      FIGS. 14   a  to  14   d  are perspective views of the interaction of a package with the system shown in  FIG. 11 , illustrating air extraction, vacuum shutdown and maintenance of the condition of the package after extraction of air. 
         [0094]    Preferably, the present invention offers the following performance parameters:
       Linear speeds up to 150 fpm   Adjustable to bag sizes (conveyor height)   No additional freeboard required (to hold the package while filling it)   Maximum footprint length of 7 feet   Air removal time estimated at 0.4 second   No air entrance into the package (after air extraction and prior to sealing)       
 
         [0101]    According to the present invention, there is also provided a method removing air from an interior of a flexible package before closure thereof, comprising the following steps:
       a) displacing the package along a horizontal direction;   b) maintaining continuously an upper part of the package closed along a significant length of its displacement;   c) partially opening the upper part of the package at a specific location along the length of the system; and   d) removing air from the interior of the package when the package is positioned, at said specific location.       
 
         [0106]    Preferably, the method further comprises the step of decreasing, along the length of the displacement, a distance between a means for displacing the package in step a) placed under the package and a means for maintaining the package closed in step b) to remove vertical tension from the upper part of the package. 
         [0107]    A package, after going through the above-described deaeration system or method, can then be sealed or closed using any sealing or closing system known in the art. 
         [0108]    Differences with Respect to the Prior Art 
         [0109]    As described in U.S. Pat. No. 7,316,102, packages must go through the hood (see 1 st  paragraph of the summary of the invention . . . “vacuum extraction hood through which the packages are conveyed”), whereas, in the present invention, the hood is replaced by a deaeration port and the package passes under the port. 
         [0110]    As described in U.S. Pat. No. 7,316,102, the open package goes through the hood and it is gradually closed by the belts facing each other and located in the upper part. In the present invention, the package is closed when it arrives at the air removal section (the package is held by the upper driving system belts) and it is partially opened. In fact, a portion of it stays closed while it is still held by the belts. This partial opening is done while the package is moving forward. 
         [0111]    With the system presented in U.S. Pat. 7,316,102, the upper part of the bag is not held before and during air extraction. On the contrary, in the present invention; the upper part of the package is continuously held, even during air extraction, ensuring an exact positioning of the upper part of the bag, thus ensuring a constant transfer to the closing system and an increase in the closing system reliability and quality of the finished product. 
         [0112]    In the invention described in U.S. Pat. No. 7,316,102, the upper part of the package is not held before the end of air extraction; whereas in the present invention, the upper part of the bag is continuously held. The distance between the conveyor which supports the lower part of the package and the belts supporting the upper parts of the package is adjustable. Consequently, it is possible to control tensions exerted to the sides of the package when the air is extracted from it. Since the distance between the conveyor supporting the lower part of the package and the belts holding the upper part of the package is controlled, the condition (behaviour) of the flap is also controlled and the distance between the closing system and the product level into the bag is decreased which reduces the freeboard required. 
         [0113]    In U.S. Pat. No. 7,316,102, air extraction is made through a big hood maintained at a negative pressure. Air is drawn up everywhere around several packages at the same time. Loss of efficiency is obvious and should be certainly quantifiable. In the present invention, air extraction is made through an aspiration port. The dimension of the air aspiration end is smaller than the upper part of the packages from which air is extracted. This small end, located very near the upper part of the package offers more efficiency (and increased performance). 
         [0114]    Moreover, the system described in U.S. Pat. No. 7,316,102 has a voluminous hood that makes the system more burdensome, even cumbersome or bulky. The present invention has a small deaeration port allowing a realization of the same functions more efficiently while keeping the system dimension to its minimum. 
         [0115]    Although the present invention has been explained hereinabove by way of preferred embodiments thereof, it should be pointed out that any modifications to these preferred embodiments within the scope of the appended claims are not deemed to alter or change the nature and scope of the present invention.