Patent Publication Number: US-11661221-B2

Title: Vacuum extraction and sealing of containers

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a division of U.S. patent application Ser. No. 16/212,039, filed Dec. 6, 2018, which claims the benefit of U.S. Provisional Application No. 62/596,632, filed Dec. 8, 2017, the disclosures of both of which are hereby expressly incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     The present disclosure pertains to extracting oxygen from filled containers by vacuum process and replacing the oxygen with an inert gas and then sealing the container. The container may be composed of metallic cans, glass jars or bottles or PET or other containers capable of withstanding reduced pressure within the container. 
     Current systems for the vacuum extraction of air/oxygen from containers and then sealing the containers include large, high production systems with as many as 30 filling heads operating simultaneously. Such machines are very expensive and not practical for most production settings where several or many different types of products are sealed within cans, bottles, or other types of containers. 
     At the other end of the spectrum are slow-speed machines for vacuum extraction of a container and subsequent sealing of the container. Such machines often require that one or more probes be inserted into the substance of the container, typically a powder, to create holes in the powder to assist in extraction of the oxygen within the powder. The drawback of requiring the use of such probes is contamination of the powder within the container, especially if food by insertion of the probes. 
     Another drawback of such machines is that when vacuum is applied to extract the air/oxygen from the container, some of the powder or other substance within the container is also extracted, thereby resulting in a loss of product from each container. 
     The present disclosure seeks to provide an apparatus and method for vacuum extraction of ambient oxygen from containers, the replacement of such oxygen with an inert gas or gas mixture and then the sealing of containers, all at a production rate that is practical for a large segment of the industry, as well as scalable to both increase or decrease production rates. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     A system for evacuating and closing containers filled with powdered content or other content includes an enclosed housing which is in communication with a vacuum source to remove the air or ambient gas in the housing and replace the removed air or gas with an inert replacement gas which contains no or very little oxygen. The housing has at least one entrance opening for receiving the containers therein to be evacuated and then closed. 
     A vacuum shroud is in registry with the container entrance opening in the housing. The shroud also is connected to a vacuum source as well as the source of replacement gas to replace the ambient air removed from the container with an inert gas. The shroud is movable between advancing the shroud to seal the container entrance opening with the shroud and retracting the shroud from the container entrance opening. 
     A container transport system is used to insert the container through the housing entrance opening and into the shroud. A sealing system seals the housing from the ambient after the container is inserted into the shroud. The sealing system may be incorporated into the structure of the container transport system. 
     The system also includes a closure subsystem for closing the containers once the ambient air is removed from the container and replaced with a substantially oxygen free replacement gas. Thereafter, an outfeed subsystem removes the closed containers from the housing while maintaining the atmospheric content and pressure level within the housing. The outfeed subsystem may include a suitable exit chamber for receiving the closed container from the housing while maintaining the vacuum level and atmospheric composition within the housing. A conveyor may be used to remove the closed container from the exit chamber and transport the closed container away from the housing. 
     The shroud includes a closed proximal end and an open distal end through which the container is received into the shroud. The distal end of the shroud is sealable relative to the entrance opening of the housing when the shroud is advanced into container receiving position at the container entrance opening of the housing. The shroud also includes an actuator to advance the shroud to seal the distal end of the shroud relative to the housing entrance opening as well as to retract the shroud away from the housing entrance opening after the air in the container has been replaced so that the container may be transferred to a sealing station for placing a cover or lid over the container and seaming the cover to the top of the container. 
     The container transport system may include a movable platform to advance the platform when inserting the container through the housing entrance opening and into the interior of the shroud. The platform is used to seal the housing entrance opening when the container is placed into the interior of the shroud. An actuator is provided to advance and retract the platform forward and away from the housing entrance opening. 
     The closure system places a closure in the form of a cover or lid over the open end of the container. The closure system thereafter seals the cover or lid to the container. Prior to such sealing, the pressure within the filled container can be reduced to a level below the pressure within the housing so as to provide a reduced pressure level within the container when sealed. 
     A cover/lid supply magazine is in communication with the housing to supply covers/lids for the containers to be closed. The cover/lid supply magazine provides a seal between the interior of the housing from the ambient so that the housing is not exposed to the ambient via the cover/lid supply magazine. 
     A method is provided for evacuating and closing containers filled with powdered material and other content wherein the air removed from the containers is replaced by an inert gas that is substantially devoid of oxygen. The method is performed in an enclosed housing having an entrance opening for receiving the container. A shroud is positioned over the entrance opening within the housing thereby sealing the entrance opening from the ambient. Ambient air is removed from the housing and replaced with the inert gas substantially free of oxygen. Thereafter, the container is presented through the housing entrance opening and into the shroud. Then, the housing entrance opening is sealed from the ambient thereby isolating the interior of the shroud with the container therein. Next, the ambient air is removed from the container by applying a vacuum to the shroud. The removed ambient air is replaced with an inert gas that corresponds to the inert gas of the housing. 
     Thereafter, the shroud is retracted so that the container can be moved to a location within the housing for closing the container, for example, by applying a cover or lid to the open top of the container and then seaming the lid to the container. Then the closed container is removed from the housing using an airlock or other system to maintain the inert gas composition and pressure level within the housing. 
     In accordance with the present method, when the container is presented to the housing entrance opening and into the shroud, the housing entrance opening and the shroud are simultaneously sealed from the ambient. 
     In accordance with the present method, the container is presented to the housing entrance opening using a linear actuator. More specifically, the container is supported on a platform that is powered by a linear actuator. Further, the platform is used to seal the container entrance opening from the ambient. 
     The housing can include an entrance opening that is capable of receiving a plurality of containers at the same time. As an alternative, the housing may include an entrance opening for each of the plurality of containers simultaneously presented to the housing. Whether the housing includes an entrance opening large enough for a plurality of containers or employs individual housing openings for each container, the housing opening(s) is/are sealed by engagement with the container platform(s). 
     The present method also includes conveying the container(s) from a filling station to the housing. 
     The method further includes entrapping the contents of the container during the evacuation of the container. In this regard, a pervious barrier may be placed over the open top of the container during the evacuation process as well as during the process of replacing the evacuated air with an inert gas. 
     During the evacuation process, the pressure within the container may be reduced to a level of about 10 to 20 mbar. More specifically, the pressure within the container may be reduced to a level of about 15 mbar. 
     The present method includes removing the shroud from the evacuated container and thereafter closing the top of the container while the container is within the housing. During the closure process, the pressure within the container can be reduced to a level below the pressure level within the housing so as to achieve an evacuated or partially evacuated container prior to the sealing of the container. The container may be sealed with a cover or lid that is seamed onto the container in a standard manner. 
     After sealing the container, the container is removed from the housing while maintaining the pressure and the inert atmosphere within the housing. This can be accomplished by transferring the sealed container from the housing via an airlock. The filled container is transferred to the airlock and thereafter the airlock is isolated from the housing before the container is removed from the airlock and transported on. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG.  1    is a pictorial view of the system of the present disclosure taken from a first or front side of the evacuation housing/chamber, and shown partially in schematic; 
         FIG.  2    is a view similar to  FIG.  1   , but taken from the opposite or back side of the evacuation housing as shown in  FIG.  1   ; 
         FIG.  3    is a side elevational view of  FIG.  1   ; 
         FIG.  4    is a side elevational view of  FIG.  2   ; 
         FIG.  5    is a fragmentary view of portions of the interior of the evacuation housing; 
         FIG.  6    is an enlarged fragmentary pictorial view of  FIG.  5   ; 
         FIGS.  7 A- 7 H  illustrate one example of a method using the system of the present disclosure; 
         FIG.  8 A  is an enlarged fragmentary cross-sectional view of  FIG.  1    specifically illustrating the construction of a shroud and lift platform; 
         FIG.  8 B  is a cross-sectional view of  FIG.  8 A  taken along lines  8 B- 8 B thereof; 
         FIG.  8 C  is an exploded view of  FIG.  8 B ; 
         FIG.  9    is a flow diagram illustrating one method of utilizing the system of the present disclosure; 
         FIG.  10    is a pictorial view of a further embodiment of the present disclosure for removal of the sealed containers from the sealing station; 
         FIG.  11    is a side pictorial view of  FIG.  10   ; 
         FIG.  12    is a pictorial view of the removal system of  FIG.  10    shown from the opposite end of the system; 
         FIGS.  13 A- 13 G  illustrate the manner of operation of the alternative removal system; 
         FIG.  14    is a flow diagram illustrating the operation of the alternative removal system; and 
         FIG.  15    is a cross-sectional schematic view of a seaming apparatus in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result. 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein. 
     The present application may include references to “directions,” such as “forward,” “rearward,” “front,” “back,” “upward,” “downward,” “right hand,” “left hand,” “in,” “out,” “extended,” “advanced,” “retracted,” “proximal,” “distal,” “above,” “below,” “in front of,” “behind,” “on top of,” and “beneath.” These references and other similar references with respect to direction, position, location, etc., in the present application are only to assist in helping describe and understand the present invention and are not intended to limit the present invention to these directions, positions, locations, etc. 
     The present application may include modifiers such as the words “generally,” “substantially,” “about,” or “approximately.” These terms are meant to serve as modifiers to indicate that the “dimension,” “shape,” or other physical parameter, in question need not be exact, but may vary as long as the function that is required to be performed can be carried out. For example, in the phrase “generally circular in shape,” the shape need not be exactly circular as long as the required function of the structure in question can be carried out. 
     In the following description, various embodiments of the present disclosure are described. In the following description and in the accompanying drawings, the corresponding systems assemblies, apparatus and units may be identified by the same part number, but with an alpha suffix. The descriptions of the parts/components of such systems assemblies, apparatus, and units are the same or similar are not repeated so as to avoid redundancy in the present application. 
     Referring initially to  FIGS.  1 - 6   , a system  20  for evacuating and sealing containers  22  filled with product, especially powdered product, is illustrated as including in basic form a transport and delivery system  24  for transporting and presenting a plurality of containers  22  to a sealed housing or chamber or enclosure  26  wherein atmospheric air is removed from the containers and replaced by an inert gas and then the containers are sealed at a closure station  28  thereby to preserve the contents within the containers. Thereafter, the closed containers are removed from the housing  26  by a removal system  30  for removing the closed containers from the housing without exposing the interior of the housing to the ambient. The containers  22  are illustrated in the form of cans, but can be of other configurations as noted below. 
     Describing the system  20  in more detail, the transport and delivery system  24  includes an infeed conveyor  40  that transports a set of containers  22  (six being illustrated as an example) from an escapement, not shown, associated with a filling station, not shown, wherein the cans are filled, typically with a powder, granular substance or similar, or other content. The plurality of containers are loaded onto the conveyor  40  from the escapement and then the conveyor is operated to position the cans  22  adjacent the infeed location at a lower level of housing  26 . An optical or other type of sensor is utilized to count the number of cans transferred from the escapement onto the conveyor and determine the locations of such containers. Also, an encoder associated with conveyor  40  stops the conveyor when the containers  22  are in position at the housing as shown in  FIGS.  1 ,  3 ,  5 , and  6   . 
     The housing/chamber  26  is illustrated as an enclosed structure that is sealed from the ambient. The structure  26  is supported by floor-engaging legs  50  depending from the bottom of the housing and from the removal system  30 . The housing is illustrated as generally rectilinear in shape, but can be of other shapes. In this regard, the housing includes a top panel  52  and a bottom panel  54  interconnected by end panels  56  and  58 . At the location that the containers  22  are presented to the housing  26  the lower portion of the housing is cut away to define a mezzanine  59  formed by a horizontal base plate  60 . A vertical longitudinal wall  62 , that intersects the inward edge of the base plate, and a transverse end wall  64  cooperatively seal off the mezzanine section of the housing from the ambient. 
     A side panel structure  66 , which is mostly open in construction, is disposed along the side of the housing where the containers  22  are presented. Such side panel structure  66  does include a footing panel  68  through which upper actuators  70  extend, as described more fully below. A pair of see-through doors  72  are positioned above the footing panel  68  and a third full height see-through door  74  is located along the side panel structure  66 . The doors  72  and  74  are sealed with respect to the side panel structure  66  so as to prevent leakage of gases between the interior of the housing and the ambient, while being of sufficient structural integrity to remain rigid and not deform during use of the system  20 . To this end, the doors may be composed of a clear/transparent plastic or a glass composition, for example, acrylic or poly(methyl methacrylate). As will be appreciated, the doors  72  and  74  not only provide visibility into the housing  26 , but also may be opened to provide access to the interior of the housing, for example, for cleaning, adjustment, maintenance, and repair, as well as to reconfigure the system  20  for use with other types or sizes of containers, etc. 
     Referring specifically to  FIGS.  2  and  4   , the “backside” of the housing is illustrated as composed of side panel structures  80  and  82  to which are fitted see-through doors  84  and  86 , respectively. The doors  84  and  86  may be of the same composition as doors  72  and  74 . The door  86  is located somewhat laterally outwardly from the doors  82  and  84 . A step wall  88  extends laterally outwardly from the side panel  80  to define the housing at that location. The doors  84  provide access to the location in which the air/oxygen is removed from the containers and replaced with inert gas. The door  86  is adjacent the location in which the closure system  28  is located, which is described more fully below. 
     As perhaps most clearly shown in  FIGS.  6 ,  7 A- 7 H, and  8 A- 8 C , a circular seal ring  87  depends downwardly from base plate  60 . The top of the seal ring  87  is flush with the top surface of the base plate. In this regard, a shoulder extends around the circumference of the seal ring to abut against the lower surface of the base plate  60 . As described more clearly below, the seal ring  87  has a central through bore or opening  94  through which containers  22  are delivered into the interior of the housing  26 . 
     A shroud assembly  96  is associated with each of the sealing rings  87  and associated opening  94 . Each shroud assembly  96  includes a shroud  98  having a cylindrical, major, upper sidewall portion  100  and a lower reduced outer diameter pilot section  89 . The shroud upper sidewall section  100  is downwardly engageable within a counter bore  90  formed at the upper portion of the sealing ring  87 , and the lower pilot section  89  of the shroud  98  closely engages within the sealing ring central opening or bore  94 . 
     An upper seal  91  is disposed within a lateral groove opening into the seal ring counter bore  90  to seal against the outer circumference of the shroud sidewall section  100 . An intermediate seal  92  likewise is disposed within a lateral groove formed in the sealing ring  87  to bear against the pilot portion  89  of the shroud sidewall. 
     The top of the shroud is closed by a top assembly  102 , while the bottom of the shroud at the bottom of the pilot section  89  is open. The shroud  98  is raised and lowered by an actuator  106  connected to the shroud top assembly  102 . 
     Referring specifically to  FIGS.  6 ,  7 A- 7 H,  8 B, and  8 C , a circular lift platform or table  120  is associated with each seal ring  87  and opening  94 . The lift platforms  120  function to lift the filled containers  22  upwardly through the sealing ring opening  94  and into the interior of a shroud  98 . The lift platform  120  includes an upper circular base section  122  that is sized to closely fit into the circular interior of the shroud. The lift platform also includes a slightly enlarged diameter lower shoulder section  124  which closely fits within the sealing ring opening or bore  94 . The lift platform shoulder section  124  seals against a lower seal  93  that is mounted in a lateral groove formed in the lower portion of the seal ring to seal against the lower shoulder section  124  of the lift platform. The lift platform is raised and lowered by a lift actuator  128  extending downwardly from the underside of the lift platform  120 . 
     It will be appreciated that when the lift platform  120  is in the fully extended upward position and the shroud  98  is in fully downward extended position, the interior of the shroud is isolated from both the ambient and the interior of the housing, as shown in  FIGS.  7 C, and  8 B . As described below, during this condition, the ambient air within the shroud and container  22  is removed and replaced with an inert gas or gas mixture at a pressure above atmospheric pressure. 
     When the shroud  98  is in lowered closed position and the lift table  120  is in extended upper position, as shown in  FIG.  8 B , both the interior of the container  22  positioned within the shroud and also the volume between the exterior of the container and the interior of the shroud are evacuated and replaced with the modified atmosphere of, for example, an inert gas or gas mixture through upper and lower ports  107  and  108  that extend horizontally radially inwardly from the exterior diameter of the ring seal  87 . The upper shroud port  107  intersects with the bottom of a vertical passageway  109  extending upwardly through the shroud upper sidewall section  100  to intersect with a horizontal annular groove  110  formed in the outer circumference of a manifold ring  111 . Radial holes  112  extend inwardly from the horizontal annular groove  110  to communicate with the open central interior  113  of the manifold ring  111 . Such open central interior  113  is in communication with the open top and thus the head space  115  of the filled container  22 . 
     Referring specifically to  FIG.  8 B , a porous barrier  114  is mounted to the underside of the manifold ring  111  inside of an annular seal  116  extending along the underside manifold ring  111 . As will be appreciated, the annular seal  116  serves to also seal the top rim of the container relative to the manifold ring  111 . The perimeter of the porous barrier also seals relative to the manifold ring and the sealing ring  116 . As such, the head space  115  of the container  22  is isolated from the exterior of the container. The barrier  114  allows air/oxygen to be drawn out of the container while substantially preventing the powder or other content within the container from escaping from the container as the container is being evacuated. The porous barrier may be composed of fabric, woven material, perforated sheet material, or other appropriate material. 
     Continuing to refer specifically to  FIGS.  6 ,  7 A- 7 H, and  8 B , the volume or space between the exterior of the container  22  and the interior of the shroud  98  is separately but simultaneously evacuated and then replaced with modified atmosphere from the evacuation of the interior of the container. The reason for this separated evacuation and modified air replacement system is to prevent powder or other contents of the container  22  from flowing from the container interior through barrier  114  during evacuation of the container and thereby contaminating the can outer surface or face with the powder or other content. Also, the vacuum and replacement gassing cycles are applied to the can head space  115  and to the can exterior at the same time thereby to avoid the can from imploding or otherwise being damaged during the vacuum cycle, especially cans with an exterior foil wrapping. In this regard, the shroud lower port  108  is in communication with an annular cavity  117  located just above the shoulder section  124  of the lift table. The cavity  117  is in fluid flow communication with an upwardly extending narrow gap  118  between the exterior of the lift table upper section  122  and the interior of the shroud upper wall section  110  as well as the shroud pilot section  89 . 
     Although the foregoing provides one example in which the interior and exterior of the container  22  may be separately but simultaneously evacuated and gassed, it is to be understood that other systems for carrying out this function may also be employed. For example, systems that evacuate and introduce replacement gas through the closed top assembly  102  of the shroud. 
     Also, the upper intermediate and lower seals  91 ,  92  and  93  can be of various construction. For example, the seals can be composed of inflatable air seals which can be inflated to achieve secure and tight seals against the shroud and lift table and also deflated to permit the shroud and lift table to be both engaged and disengaged from the sealing ring  87  without any significant resistance against the seals. Of course, other types of seals may be employed, for example O-ring seals, V-seals, double or even triple V-seals, etc. 
     The containers  22  that are delivered to the housing  26  by infeed conveyor  40  are moved laterally off the infeed conveyor and onto the lift platforms  120  by a lateral pusher system  140 , as shown in  FIGS.  1 ,  5 ,  6 , and  7 A- 7 H . The pusher system  140  includes a horizontal push bar  142  for pushing against the sides of the cans  22  to remove the cans from the conveyor  40  and onto an associated base  122  of lift platform  120 . The push bar  142  may be contoured along its leading edge  143  adjacent the containers  22  so that the containers are indexed into correctly spaced positions along the conveyor  40 . If the cans  22  are not accurately spaced along the conveyor  40  to match the positions of the lift platforms  120  and corresponding seal ring/housing openings  94 , the pressing or urging of the contoured leading edge  143  of push bar  142  against the sides of the filled containers will reposition the containers relative to each other so that they are in proper registry with the positions of the lift platforms  120  and housing openings  94 . 
     A linear actuator  144  is provided to support and actuate the push bar  142  to push the cans from the conveyor  40  and onto the lift platform  120 . As shown in  FIG.  7 A , a bridging ramp  146  is provided so that there is continuous surface between the conveyor  40  and the lift platform base  122  along which the containers  22  may be slid when pushed by the push bar  142 . Although two separate pusher systems  140  are shown in  FIG.  6   , one for each set of three containers  22 , a single pusher system  140  may be utilized or more than two pusher systems may be utilized. 
     Continuing to refer specifically to  FIGS.  1 ,  5 ,  6 , and  7 A- 7 H , a second pusher system  150  is provided at an elevation above the pusher system  140 . This second pusher system includes actuators  70  that function to push the cans  22  laterally after the shroud  98  has been retracted upwardly once the container  22  has been evacuated and the removed ambient air replaced with an inert gas or gas mixture, see  FIG.  7 F . At this point, the containers are pushed by the pusher system  150  onto a seamer infeed conveyor  156 . during for transport to the closure/seaming station  28 . To this end, the pusher system  150  includes a horizontal pusher bar  158  that is actuated by horizontal actuators  70  mounted to extend laterally outwardly from housing  26 . The actuators  70  are sealed with respect to the housing to maintain the atmospheric conditions within the housing. As noted above, such atmospheric conditions include a low level of residual oxygen in a gas mixed environment and an over-pressure of, for example, about 20 mbar gauge. 
     After the actuators  70  push the containers  22  from the lift platforms  120  and onto the seamer infeed conveyor  156 , a container guide bar  160  is simultaneously raised along the conveyor  156  next to the baseplate  60  to restrain the containers in the lateral direction relative to the direction of travel of the conveyor  156 . See  FIG.  7 G . The guide bar is located between the side of the conveyor  156  and the baseplate  60  as shown in  FIGS.  7 A- 7 H . The guide bar is raised and lowered between conveyor  156  and the baseplate  60 . The guide bar  160  is in the lowered position allowing for the container to be transferred from the lift platform  120  on to the seamer infeed conveyor  156 , see  FIG.  7 F . Following the transfer of the container the guide bar is raised creating a guide for the container to transfer along the conveyor without risk of the container being dislodged, see  FIG.  7 G . 
     The seamer infeed conveyor  156  transports the containers  22  to a closure/sealing/seamer station  28  which perhaps is most clearly shown in  FIG.  5   . As with the conveyor  136 , the seamer station  28  is also within the sealed chamber  26  wherein the chamber includes a modified atmosphere environment to maintain the low residual oxygen level achieved in the container following the extraction of the Oxygen and replenished with gas injection. To this end, the containers  22  are fed into circumferential, outwardly open pockets  170  formed along the circumference of a rotatable double star wheel  172  that is mounted on a central rotatable shaft  173 . A floor  174  is provided for supporting the containers  22  when inserted within the pockets  170 . The containers are secured in the star wheel pockets by a guide rail or other means with a clearance of approximately 2 mm between the guide rail and the depth of the star wheel pocket. This clearance allows for a degree of flexibility to accommodate the potential variance in the tolerance of the container dimensions. 
     The double star wheel  172  is indexed from a first position/station in registry with the seamer infeed conveyor to a second position/station in registry with a stack magazine  180  filled with covers  182 , which are placed onto the open top of the containers at the magazine station. Next, the double star wheel  172  is indexed to a seaming station  190  wherein a cover  182  is seamed to the upper edge of the container  22  in a standard manner Such seamers are articles of commerce. 
     The above process of placing the covers  182  on the containers  22  and then seaming the containers can occur one at a time as each can is shifted from the seamer infeed conveyor to the double star wheel. Alternatively, all of the containers  22  can be loaded on the double star wheel at the same time so as to fill the pockets of the double star wheel and then the covers  182  applied to the filled star wheel cans and thereafter the covers are seamed with the containers  22 . In this manner, the seamer infeed conveyor  156  is emptied quickly so that a second set of evacuated containers  22  can be loaded onto the seamer infeed conveyor. 
     The outer circumference of the covers  182  snugly slides against the inside surface of the lower collar portion  184  of the magazine  180 . In this manner, the covers acting against the collar  184  provide a seal between the interior of the housing  26  and the ambient. To this end, it is desirable that a sufficient number of covers  182  are positioned within the magazine  180  so as to maintain a seal with the collar portion  184 . 
     As noted above, the sealed containers  22  are removed from the housing  26  while maintaining the atmosphere within the housing. To this end, as perhaps most clearly shown in  FIGS.  1 - 5   , removal system  30  includes an airlock structure  200  having an elongated housing  202  positioned over an outfeed conveyor  204  powered by an actuator  205 . The airlock structure  200  includes sealable doors  206  and  208  at the opposite end of the housing  202  for the purpose of allowing entry of the sealed cans into the airlock structure, and then out of the structure via the outfeed container  204 . While the airlock structure  202  is empty, the pressure within the airlock may be reduced to match the pressure within the structure  202  and the ambient air within the structure  202  may be replaced with the same inert gas or gas mixture utilized within the housing  26  so that when the near door  206  is open, the atmosphere within the structure  202  matches the atmosphere within the interior of the housing  26 . Thereupon a set of sealed cans may be advanced into the airlock structure  202  and then the near door  206  closed to seal the housing  26  from the airlock structure  202 . Therefore, the far door  208  of the airlock structure may be opened and then the sealed cans removed from the airlock structure by operation of the outfeed conveyor  204 . 
       FIGS.  7 A- 7 H  together with  FIG.  9    illustrate one example of the use of the present system  20  for replacing the air in containers  22  with modified or inert gas or gas mixture and then sealing the container  22 . Under such conditions, the content within the container  22  can be maintained in a preserved state for a prolonged period of time, especially if the content consists of food. Substantially all of the oxygen has been removed from the container which minimizes degradation of the container content. 
     The method begins at step  250  wherein the system  20  is set to start-up conditions or parameters. In this regard, the vacuum shrouds  98  are in lowered position to close off the entrance openings  94  in the seal ring  87  of the housing  26  via upper end intermediate seals  91  and  92 . See  FIG.  7 A . The lift platforms or tables  120  are in down position for reception of the filled containers  22  from the filling station. Any residual oxygen in the housing  26  is flushed out and replaced with a modified atmosphere composed of, for example, nitrogen, carbon dioxide or a mixture thereof. The pressure within the housing may be set to approximately 20 mbar gauge, which is achieved by opening and closing the exhaust and modified atmosphere gas valves. Of course, the over-pressure within the housing  26  can be at other levels either above or below 20 mbar gauge. The residual oxygen level in the housing is reduced to a range of about 2.5% to 0.5% by volume or less. In one non-limiting example, the residual oxygen level may be about 1.5% by volume. 
     After the foregoing startup conditions are met, in step  252 , in the operation of system  20 , the system confirms that there are a desired number of containers  22  at the escapement from the filling station and that the containers are filled with the desired amount of material, e.g., powder material. 
     Next, in step  254 , the filled containers  22  are transferred onto an infeed conveyor  40  and then in step  256  the containers are transported by the infeed conveyor to a position in front of the evacuation housing  26  at a lower elevation of the housing, for example, as shown in  FIGS.  1  and  3   . 
     Next, in step  258 , the pusher system  40  is used to push the containers of the set onto individual lift tables or platforms  120 , see  FIGS.  7 A and  7 B . The lift tables  120 , which are in lowered position below the mezzanine  59  of the housing. In step  260 , the actuators  144  of the pusher system  140  are retracted to their nominal (home) position so that the next set of containers  22  can be moved onto the escapement to be ready for the next cycle. 
     Next, at step  264 , as shown in  FIG.  7 C , the lift platforms  120  are raised to lift the containers  22  into position within a corresponding shroud  98 . The lift platforms simultaneously seal against the bottom or lower seal  93  of the base seal ring  87  to close off the entrance openings  94  from the ambient. 
     Next, at step  266 , the pressure within the container  22  is evacuated through port  107  down to approximately 15 mbar (ABS) thereby to help ensure that each container has no more than about 2.5% to 0.5% residual oxygen by volume therein once the inert replacement gas has been injected into the shroud, also through upper port  107 . The porous barrier  114  disposed over the open top of the container  22  during the evacuation process prevents powder or other material within the container from escaping. See  FIG.  7 D . At the same time, the pressure between the exterior of the container and the interior of the shroud is also simultaneously evacuated to the same pressure level as within the container via lower port  108 . As a non-limiting example, the evacuation of the container  22  as well as the evacuation of the volume between the exterior of the container and the interior of the shroud can be accomplished in about 5 seconds; however, this process can be carried out over a shorter or longer period of time. 
     Next, at step  268 , a modified atmosphere composed of, for example, nitrogen, carbon dioxide, or a mixture of both is injected into the container through upper port  107 . Such injection of the modified atmosphere is blown through the porous barrier  114  thereby to blow off from the barrier any material or powder that has collected thereon during the evacuation process. See  FIG.  7 D . Simultaneously, the same modified atmosphere is injected through port  108  to fill the volume between the exterior of the container  22  and the interior of the shroud  98 . As a non-limiting example, the modified atmosphere can be injected into the container  22  as well as into the volume between the exterior of the container and the interior of the shroud at a pressure of about 1.5 bar for a time period of about 1 second. This process can be carried out at other pressures and for other time durations. 
     At this stage, the oxygen level within the container and shroud and the pressure within the container and shroud could match the atmospheric conditions within the housing itself. However, it may be desirable if the pressure within the container and within the shroud were either higher or lower than the pressure within the housing. For example, if the pressure within the container  22  and shroud  98  is higher than that within the housing, this can help maintain the low residual oxygen level within the container. 
     Next, at step  270 , the shroud  98  is retracted upwardly to an elevation above the containers (see  FIG.  7 E ), thereby exposing the container  22  to the atmosphere within the housing. 
     Then at step  272 , the containers  22  are moved laterally by upper pusher system  150  to a seamer infeed conveyor  156 , as shown in  FIG.  7 F . With the containers now removed from the lift platform  120  at step  274 , the shrouds  98  are lowered to close off the openings  94  in the base plate  160 , see  FIG.  7 G . Next, at step  276 , the platforms  120  are lowered, as shown in  FIG.  7 H , to await the next group of containers  22  from the infeed conveyor  40 . 
     Thereafter, as set forth in step  278 , the filled cans  22  are conveyed by the seamer infeed conveyor  156  to engage within a pocket  170  of star wheel  172 . Next, at step  280 , the star wheel is indexed (rotated) by the use of an encoder positioned on the drive shaft  173  of the star wheel. Simultaneously, at step  282  the number of can lids  182  in the magazine (stack)  180  is monitored to ensure that a seal is maintained between the interior of the housing and the external environment, which seal is created by the stack of container lids  182  in the base portion  184  of magazine, step  282 . 
     At step  284 , a container lid  182  is placed on the open top of each of the containers  22  when the container is positioned below the lid magazine  180 . At step  286 , the double star wheel  172  is indexed to present the container  22  with the lid/cover  182  thereon to a seamer station whereat the container is lifted and rotated to affix the lid  182  to the container  22  in a standard manner. 
     At step  288 , after the lid  182  is affixed, the container  22  is lowered and the star wheel  172  is indexed again to present the sealed container onto an exit conveyor  204 . This process is repeated until all of the covers/lids  182  have been attached to the containers. 
     Next, at step  290 , the sealed containers as a group are transported into the airlock  200 . After the airlock  200  has been sealed from the housing, at step  292 , the containers are transferred out of the airlock as a group onto the exit conveyor  204 . 
     The foregoing represents merely one example of a method of utilizing the system  20  of the present disclosure. It is possible that some of the foregoing steps might be combined or eliminated or modified or replaced with a different step while still resulting in an efficient method for evacuating and sealing containers  22 , especially containers filled with powdered material. 
     While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. 
     For example, although the present disclosure describes processing a plurality of containers in sets of six at a time, a lesser or greater number of containers may be processed as a batch. For example, 4, 5, 7, 8, 9, or 10 containers could be processed as a batch. 
     As a further alternative, although a separate lift platform  120  is described and illustrated for each container  22 , a plurality of containers may be positioned on a singular lift platform and the plurality of containers lifted upwardly into a shroud for each container or a shroud for multiple containers. 
     Further, various types of containers may be processed utilizing the system  20  of the present disclosure. Such containers may consist of metallic cans, glass jars or bottles, PET or other containers capable of sustaining a reduced pressure within the container. 
     Although a specific seal arrangement has been described and illustrated for sealing the shroud  98  with respect to the housing opening  94  as well as the lift platform  120  relative to the housing opening  94 , other sealing arrangements can be utilized. For example, the bottom of the shroud can be sealed against the top surface of the base plate  60 , and the lift platform  120  can be sealed against the underside of the base plate  60 . 
     Further, although the airlock housing  202  is illustrated as being at the elevation of the star wheel  172 , the airlock housing can be located at or near the level that the containers  22  are placed on the lift tables by the pusher system  140 . In this regard, the elevation of the infeed conveyor  40  may be substantially the same as the elevation of the outfeed conveyor  204  which may be desirable in certain installations. 
     Also, the process of removing oxygen from the interior of the housing  26  and replacing it with modified atmosphere consisting of, for example, inert gas, can be carried out using procedures and parameters other than described above. Likewise, the evacuation of the containers  22  and the evacuation of the volume between the exterior of the containers and the interior of the shrouds  98  can be performed under process conditions other than as described above. 
       FIGS.  10 ,  11 ,  12 ,  13 A- 13 G, and  14    illustrate an alternative system  300 , and corresponding structure and method, for removing the sealed containers  22  from the housing  26 . The system  300  may be used in lieu of system  30  described above. System  300  includes a discharge housing  302  which is shown in  FIGS.  10 ,  11  and  12    with portions removed so that the interior components of the system can be viewed. The housing  300  does include an entrance wall  304  which extends upwardly from a floor  305  and is transverse to incoming conveyor  306 . The conveyor  306  may be a separate conveyor or may be the same conveyor as conveyor  204  described above. Downstream of the entrance wall  304 , the housing includes an airlock wall  308  which supports side-by-side airlock chambers  310 A and  310 B. An exit wall  312  is located at the end of the housing downstream of the airlock wall  308 . The incoming conveyor  306  terminates at one side of the airlock wall  308  and a second takeaway conveyor  314  extends from the opposite side of the airlock wall  308  and out through the exit wall  312  through an exit opening  316 . It is to be understood that the housing  302  also has side walls and a top wall. Moreover, the entrance wall  304  is integrated with the end panel  58  of the housing  26 . 
     The space between the entrance wall  304  and airlock wall  308  defines a first transfer location where containers  22  are moved laterally off of the conveyor  306  and onto transfer structures  320 A and  320 B. The transfer structures include a support floor or platform  322  composed of a plurality of parallel spaced-apart bars  324  for supporting the underside containers  22 . The bars  324  are cantilevered from the base of the transfer structures. The containers  22  are moved laterally from the conveyor belt  306  onto the platform  322  by a lateral actuating system  330  composed of a vertical pushing wall  332  that depends downwardly from the actuator  330  which spans between support sections  338  that depend downwardly from an overhead ceiling structure, not shown. The powered actuator  330  moves side to side between the support sections  338  whereby the pushing wall  332  pushes the containers  22  laterally from the conveyor belt  306  onto the platform portions  322  of the transfer structures  320 A and  320 B. 
     The transfer structures  320 A and  320 B are supported for movement in the direction parallel to the length of the conveyor  306  by an actuating system  340  which extends parallel to the conveyor  36  on each side thereof. The actuating systems are supported by column structures  343  that depend downwardly from the overhead ceiling structure (not shown). The actuating system  340  functions to move the transfer structures  320 A and  320 B toward and away from airlock chambers  310 A and  310 B, as depicted by arrow  344 . The transfer structures  320 A and  320 B also include an airlock door  346  which seals the adjacent opening of the airlock chambers  310 A and  310 B when the transfer structures  320 A and  320 B have been advanced toward the airlock chambers whereby the doors  346  close off the airlock chambers  310 A and  310 B. 
     The removal system  300  also includes transfer structures  350 A and  350 B on the opposite side of the airlock wall  302  from the location of the transfer structures  320 A and  320 B. The transfer structures  350 A and  350 B include a platform or floor  352  composed of a plurality of spaced apart longitudinal bars  354  capable of supporting the containers  22  therein. The bars  354  are cantilevered from the base of the transfer structures  350 A and  350 B. The transfer structures  350 A and  350 B are movable in the longitudinal direction, parallel to conveyor  306 , by actuating systems  360  which include transfer sections  350 A and  350 B moveable in the direction along the length of the conveyor  306 . The actuators  360  are supported by columns  364  that depend downwardly from the overhead ceiling structure (not shown). 
     As in the transfer structures  320 A and  320 B, the transfer structures  350 A and  350 B also include airlock doors  362  that are configured to close off the adjacent side of the airlock chambers  310 A and  310 B when the transfer structures  350 A and  350 B are advanced toward the airlock chambers  310 A and  310 B. It will be appreciated that when the transfer structures  320 A or  320 B and the corresponding transfer structures  350 A or  350 B are positioned so that the airlock doors  346  and  362  close off the airlock chambers, the support bars  324  of the floor  322  nest between the support bars  354  of the floor  352 . 
     The transfer structures  350 A and  350 B are also constructed to move laterally with respect to the length of conveyor belt  306  by a lateral support and actuating system  370  which includes a guideway  372  for guiding the lateral movement of the transfer structures  350 A and  350 B so that once the containers  22  are removed from the airlock chambers, the containers can be moved laterally onto the takeaway conveyor  314 . It will be appreciated that rather than using actuating system  370 , the containers  22  can be removed from the transfer structures  350 A and  350 B using a lateral actuating system similar to actuating system  330  described above. 
     The functioning of the removal system  300  is schematically illustrated in  FIGS.  13 A- 13 G  as well as in the flow diagram of  FIG.  14   . At the start step  400  shown in  FIG.  14   , the containers  22  are positioned on the incoming conveyor  306  as shown in  FIG.  13 A . In step  402 , as shown in  FIG.  13 B , a first container  22 A is pushed laterally off of the conveyor  306  by the lateral actuator  330  and onto platform  322 , see arrow  413 . 
     In the next step  404 , as shown in  FIG.  13 C , the container  22 A is pushed into the airlock chamber  310 A by the longitudinal movement of the transfer structure  320 A, see arrow  414 . The transfer structure  350 A has already been positioned against the airlock chamber  310 A. Simultaneously, a second container  22 B is pushed transversely from the conveyor  306  onto platform  322  of the transfer structure  320 B via lateral actuator  330 . 
     In the next step  406 , the container  22 A is removed from the airlock chamber  310 A by the longitudinal movement of the transfer structure  350 A, as shown in  FIG.  13 D , see arrow  415 . During this transfer process, the transfer structure  320 A remains engaged with the airlock chamber  310 A so as to isolate the airlock chamber from the housing between the entrance wall  304  and the airlock wall  308 . Simultaneously, the container  22 B is placed into the airlock chamber  310 B by the longitudinal advancement of the transfer structure  320 B, see arrow  416 . As shown in  FIG.  13 D , the transfer structure  350 B is already in place with the airlock door  362  sealing the adjacent side of the airlock chamber  310 B. 
     In the next step  408 , as shown in  FIG.  13 E , the container  22 A is transferred onto the takeaway conveyor  314  by the lateral movement of the transfer structure  350 A via the lateral actuating system  370 , see arrow  417 . As noted above, rather than using the lateral actuating system  370 , the lateral transfer of the containers from the transfer structures  350 A and  350 B onto the takeaway conveyor  314  can be accomplished using a lateral actuator similar to lateral actuator  330  described above. 
     In the next step  410 , as shown in  FIG.  13 F , the container  22 B is removed from the airlock chamber  310 B by the longitudinal movement of the transfer structure  350 B in the direction of arrow  420 . Simultaneously, the transfer structure  350 A is moved longitudinally in the direction of arrow  422  so that the airlock door  362  is engaged against the adjacent end of the airlock chamber  310 A. Also, the transfer structure  320 A is moved longitudinally in the direction of arrow  424  away from the airlock chamber  310 A to be in position to receive the next container  22 C. 
     The cycle is shown as beginning to repeat itself in step  412  as depicted in  FIG.  13 G , wherein the container  22 B is shifted laterally onto the takeaway conveyor  314 , as shown by arrow  428 , and thereafter the transfer structure  350 B is positioned against the outlet side of the airlock chamber  310 B, as shown by arrow  429 . Thereafter, the transfer structure  320 B is shifted longitudinally in the direction of arrow  430  so that the platform or floor  322  is removed from the airlock chamber  310 B and is in place to receive the container  22 D. Simultaneously with the foregoing, the container  22 C is shifted laterally from the conveyor  206  onto the platform  322  of the transfer structure  320 A. 
     It will be appreciated that in the foregoing manner by the use of two airlock chambers  310 A and  310 B, the containers  22  may be rapidly and efficiently removed from the closure/sealing station  28  so as to achieve a high throughput for the overall system  20 . 
       FIG.  15    illustrates a system  500  for placing the covers  182  on containers  22  when it is needed or desirable to have a negative pressure in the container at the time of sealing the container. In this regard, an airtight shroud  502  is placed around the seaming rollers  504 , and the shroud  502  is sealed to the lift table  506  of the seaming apparatus  500 . 
     More specifically, a shroud  502  is formed with a smaller diameter lower portion  508  encircling most of the container  22  except at the upper portion thereof at the elevation of the seaming rollers  504 . At the upper portion of the shroud  510 , the area of the shroud is increased to accommodate the seaming rollers  504  which are outside of the perimeter of the cover  102  and container  22 . The shroud upper portion  510  seals against the underside of a top plate  512 . An O-ring  514  or other type of seal is used to seal the bottom of the shroud  502  against the lift table  506  of the seaming apparatus. The seaming apparatus  500  also includes a seaming chuck  516  that places the covers  182  over the top of the containers  22  and holds the cover in place while the seaming rollers  504  seal the covers  182  to the containers  22 . 
     Before a cover  182  is attached to the top of a container  22 , a pre-set vacuum is generated in a vacuum reservoir  518  using a vacuum source  520  interconnected with the vacuum reservoir  518  by a first valve  522 . Just prior to seaming the cover  182  onto the container  22 , a second valve  524 , located between the vacuum reservoir  518  and the interior of the shroud  504 , is opened to equalize the pressure between the vacuum reservoir and the interior of the shroud to the desired level, i.e., desired negative pressure. The container  22  is then sealed with the cover  182  resulting in the desired negative pressure level within the sealed container. 
     While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.