Abstract:
A seal for the selective sealing of a rod which is reciprocatable within an opening through the wall of an enclosure such as the filling station of a packaging machine, the seal being actuatable to selectively provide a fluid-tight seal between the rod and the wall and release of the seal for free non-sealed movement of the rod within the opening. A method is disclosed.

Description:
FIELD OF INVENTION  
         [0001]    This invention relates to packaging machines and particularly to seals for clean-in-place enclosures for packaging machines.  
         BACKGROUND OF INVENTION  
         [0002]    Packaging machines of the form-fill-seal type generally involve the formation of a carton, filling the carton with a product, and thereafter sealing the carton. When the product is a food product, such as juice or milk, the interior of the carton is maintained clean. At the end of a production shift, or at the end of a given production run, or in other instances, it becomes necessary that the portion of the machine which is exposed directly to the product, particularly within a filling station of the machine, be cleaned and/or sterilized. The cleaning operation generally involves flushing clean water over and/or through the components within the filling station, followed by washing with chemicals, in some instances, and sterilization of the cleaned equipment by exposure to a sterilant such as high temperature water and/or a sterilant such as hydrogen peroxide.  
           [0003]    Desirably, this cleaning and/or sterilization is accomplished without the disassembly or removal of one or more of the components of the filling station equipment. Following cleaning of the components, the cleaned and/or sterilized equipment is to be maintained clean until the machine is again placed into production. Toward these ends, it is common to encase the filling equipment of a packaging machine within a “clean-in-place” enclosure, which in most instances comprises a housing which is capable of being made fluid-tight, and within which the sterilized equipment is housed. During a filling operation, a portion of this housing is open for the movement of cartons into and out of the enclosure, hence through the filling station. This opening through which the cartons pass is provided with a removable cover which, when in place, renders the entire housing fluid-tight.  
           [0004]    In a high-speed packaging machine, empty cartons are moved via a conveyor into the filling station at a location beneath one side corner of the enclosure. When so located, the bottom end of the carton is engaged by a lift arm mounted on the end of a first vertically oriented reciprocative lift rod. Substantially simultaneously, the top end of the carton is engaged by a retainer which is mounted on the end of a second vertically oriented reciprocative lift rod, thereby capturing the carton between the lift arm and the retainer. The first and second lift rods move upwardly from the conveyor and move the captured carton into the filling station enclosure. This action is rather dynamic and each carton must be grasped and held substantially stationary within the enclosure. These lift rods and their functions are more particularly described in an application filed simultaneously herewith, entitled: ______, which application in its entirety is incorporated herein by reference.  
           [0005]    Within the enclosure, the carton is filled with product. Thereafter, the first and second lift rods are moved downwardly to redeposit the filled carton on the conveyor. Once the filled carton is deposited onto the conveyor, the lift arm and the retainer disengage from the carton and remain in position to engage and move a further empty carton into and out of the filling station enclosure. Each of these reciprocative lift rods passes through the bottom wall of the enclosure. By reason of the high speed of the packaging machine, for example, 150 cartons filled per minute, each rod moves through its reciprocatory cycle at a high rate of travel and a large number of times over a short period of operating time, thereby creating severe wear upon any type of known sealing arrangement between a lift rod and the bottom wall of the enclosure.  
           [0006]    During the time that a carton is in the enclosure and being filled, there is no need for sealing between each of the lift rods and the bottom of the enclosure, and in fact, it is most desirable that there be minimal or no frictional drag between a lift rod and any mounting of the lift rods in the bottom wall of the enclosure when the lift rods are in motion. However, for cleaning-in-place of the filling equipment housed with the enclosure, it is required that each lift rod be sealed fluid-tight relative to the bottom of the enclosure to avoid escape of cleaning fluid and sterilant from the enclosure to the ambient environment.  
         SUMMARY OF INVENTION  
         [0007]    In accordance with one aspect of the present invention, there is provided a novel sealing structure which provides for minimal or no engagement of the seal with a lift rod which is reciprocating within an opening through the thickness of the bottom of the enclosure, but which is selectively actuatable to provide a fluid-tight seal between a lift rod and the bottom wall of the enclosure upon the commencement of a clean-in-place operation for the filling components housed within the enclosure. At noted hereinabove, the opening in the enclosure through which a carton is introduced to and removed from for filling of the carton, is readily closable, fluid-tight, as by a removable cover for this opening. Employing the present invention, no disassembly of any portion of the filling components housed with the enclosure is required, and the required sealing of the spacing between the lift rod and the bottom of the enclosure takes place automatically upon commencement of the clean-in-place operation. In similar manner, upon completion of the clean-in-place operation, either substantially simultaneously, or upon commencement of a subsequent operation of the overall packaging machine, the sealing structure of the present invention may be reversed and the lift rod released to freely reciprocate through the seal associated with the bottom wall of the enclosure.  
           [0008]    In a specific embodiment, the sealing structure of the present invention includes a stationary seal plate adapter mounted to the bottom wall of the enclosure, a seal actuator/bearing component, and an annular resilient member, such as an “O”-ring, disposed within a radially tapered-wall annular space defined between the adapter and actuator/bearing component and encircling the lift rod passing through the sealing structure. The diameter of the “O”-ring is chosen to be greater than the outer diameter of the lift rod which is encircled by the “O”-ring. In operation, the “at rest” “O”-ring disengages itself from the outer circumference of the lift rod. Upon actuation, the actuator/bearing component is urged toward the seal plate adapter to thereby reduce the internal volume of the tapered-wall annular space and compress the “O”-ring into sealing engagement with the outer circumference of the lift rod, thereby effecting the desired sealing between the lift rod and the bottom wall of the enclosure. 
       
    
    
     BRIEF DESCRIPTION OF FIGURES  
       [0009]    [0009]FIG. 1 is a representation of a portion of a packaging machine and depicting a filling station thereof, along with certain of the components of the present invention;  
         [0010]    [0010]FIG. 2 is a representation, in section, of the clean-in-place enclosure for the packaging machine depicted in FIG. 1 and depicting various of the features of the present invention;  
         [0011]    [0011]FIG. 3 is an enlarged view of a portion of the enclosure depicted in FIG. 2;  
         [0012]    [0012]FIG. 4 is a side elevation view, in section, of a clean-in-place enclosure and various of the carton-filling components associated therewith and depicting various features of the present invention;  
         [0013]    [0013]FIG. 5 is a representation of a first reciprocative lift rod having a carton pull-down device mounted on the top end thereof and a second reciprocative lift rod having a carton lift arm mounted on the top end thereof;  
         [0014]    [0014]FIG. 6 is a representation of a seal plate adaptor as employed in one embodiment of the present invention;  
         [0015]    [0015]FIG. 7 is a representation of an actuator/sealing component as employed in one embodiment of the present invention;  
         [0016]    [0016]FIG. 8 is a representation of a piston member employed in the actuation of the seal of the present invention;  
         [0017]    [0017]FIG. 9 is a representation of a housing for the piston member depicted in FIG. 7;  
         [0018]    [0018]FIG. 10 is a representation of a bottom plate for the housing depicted in FIG. 8; and,  
         [0019]    [0019]FIG. 11 is a representation of a subassembly including the piston depicted in FIG. 7 contained with the housing depicted in FIGS. 8 and 9. 
     
    
     DETAILED DESCRIPTION OF INVENTION  
       [0020]    Referring initially to FIG. 1, there is depicted a typical packaging machine  10  for the formation of rectangular cartons  12 , filling these cartons with a product, such as a juice or milk, and sealing of the filled cartons. More specifically, in the depicted machine and as is well known in the art, a plurality of individual carton blanks are erected into individual rectangular cylindrical cartons  12  which have their respective bottom ends  14  closed and sealed. These bottom-sealed cartons are disposed on a conveyor  16  with their open tops facing upwardly, for transport to a filling station  20 .  
         [0021]    The depicted filling station  20  includes a reservoir  22  of product from which flowable product is transferred via conduits  24 ,  26 ,(typical), through valving systems  28 ,  30  and into fill tubes  32 ,  34  whose terminal ends  36 ,  38  are housed internally of an enclosure  40 . In the embodiment depicted in FIG. 1, the machine is provided with two essentially identical enclosures at the filling station  20  and each enclosure is provided with two filling tubes that project into a respective enclosure. By this means, two cartons may be filled at the same time within each of the two enclosures, four cartons being filled simultaneously. If desired, more or fewer enclosures may be employed, as well as more or fewer filling tubes per enclosure.  
         [0022]    Each enclosure  40  in the depicted embodiment includes a top wall  42 . The fill tubes  32 ,  34  pass through this top wall and are sealed fluid-tight with respect to this top wall. Opposite the top wall, each enclosure is provided with a bottom wall  44 . This bottom wall is joined to the top wall by opposite first and second side walls  46  and  48  and opposite front and rear walls  50  and  52 , respectively (See also FIGS. 2, 3 and  4 ). Further in the depicted embodiment, the bottom wall is approximately one half the area of the top wall and extends from its juncture  54  with the front wall in the direction of the rear wall. The rear wall is approximately one half the area of the front wall and extends downwardly from its juncture  56  with the top wall. This structure defines a truncated open corner  58  of the enclosure between the terminal edge  60  of the bottom wall, the terminal edge  62  of the top wall and the opposite side walls. This truncated open corner thereby provides for ingress and egress of cartons into and out of the enclosure. A removable cover is provided for fluid-tight sealing the truncated open corner of the enclosure.  
         [0023]    Referring specifically to FIGS. 3 and 4, below each enclosure each carton  12  is engaged at its bottom end  14  by a lift arm  74  which is rigidly mounted on the upper end  76  of a first lift rod  78 . In the depicted embodiment, the lift arm  74  simultaneously engages two cartons and lifts the two cartons into the enclosure for filling. For purposes of clarity, only one carton is depicted in FIGS. 1, 2,  3  and  5 .  
         [0024]    Substantially simultaneously with the engagement of the two cartons by the lift arm  74 , the top end  80  of each of these two cartons is engaged by a pull-down frame  82  which is mounted on the top end  84  of a second lift rod  86 . The depicted pull-down frame is generally of planar geometry, having top and bottom surfaces  88  and  90 , respectively. The depicted frame is provided with two openings  92  and  94 , each being sized to permit the frame to receive therein the terminal end of one of the stationary fill tubes disposed within the enclosure and to further permit the frame to move along the length of respective ones of the fill tubes  32  and  34 . Notably, each of these openings is of rectangular geometry and of a size which provides for the bottom surface  90  of the frame adjacent each opening to engage the top end of a carton, thereby preventing the carton from moving upwardly with respect to the frame and to permit downward movement of the frame to urge the carton downwardly for the purpose, among others, of enhancing the rate of filling of a carton, without excessive spillage of product fed into the carton via a fill tube. Thus, the reciprocatory cycle of each of the lift rods  76  and  84  are independently controlled.  
         [0025]    Referring to FIGS. 2, 3 and  4  specifically, it will be noted that only the second lift rod  86  passes through the bottom wall  44  of the enclosure. In accordance with one aspect of the present invention, this lift rod  86  is provided with a selectively activated seal  100  between the lift rod  86  and the bottom wall  44  of the enclosure.  
         [0026]    Referring yet to FIGS. 2 and 3, one embodiment of a seal embodying various features of the present invention includes a seal plate adapter  102  (FIGS. 4 and 5), which comprises an elongated plate member having top and bottom surfaces  104 ,  106  and is adapted to be stationarily mounted to the bottom wall of the enclosure as by bolts or other equivalent fasteners  108 ,  110  which pass through slots  112 ,  114  that extend through the thickness of the plate. Generally centrally of the plate, there is defined a throughbore  116  having an inner wall, which in the depicted embodiment, is defined by first, second and third wall portions  120 ,  122 ,and  124 , respectively. The first portion  120  of the inner wall of the throughbore  116  extends inwardly of the throughbore from the top surface  104  of the plate only a short distance sufficient to define a straight cylindrical geometry wall portion  120  of limited diameter. From the innermost edge  126  of the first wall portion, the inner wall of the throughbore flares outwardly and downwardly into the throughbore to define a tapered wall portion  122 . The innermost edge of the tapered surface defines a juncture  128  with the innermost edge of the third portion  124  of the wall of the throughbore, whereupon the third wall portion  124  extends from this juncture to the surface  106  of the bottom wall of the plate. This third wall portion  124  is of a straight cylindrical geometry.  
         [0027]    The seal  100  further includes an actuator/bearing component  130  which, as depicted in FIG. 7, comprises a ring having top and bottom surfaces  132 ,  134 , respectively, and an outer wall  136 . This ring is provided with a central opening  138  which extends through the thickness of the ring. The top surface  132  of the depicted ring defines a tapered surface  140  which extends outwardly and upwardly from a juncture  142  with the inner wall  144  of the central opening  138  of the ring. Notably, the taper of this surface of the ring is opposite the taper of the second portion  122  of the inner wall of the throughbore of the adapter plate. Further, the outer diameter of the ring is chosen to permit slidable receipt therein of at least a portion of the top end  146  of the ring within that portion of the throughbore which is defined by the third wall portion  124  thereof. In this manner, the tapered wall of the second wall portion  122  of the throughbore of the plate and the tapered surface  140  of the ring may be disposed in facing relationship to one another to define therebetween an annular space  150  (FIG. 3) having opposing tapered surfaces. Further, depending upon the spatial separation of these tapered surfaces from one another, the annular space  150  defined therebetween may include a straight cylindrical wall section  152  of the third wall portion  124  of the throughbore. It will be recognized that when these tapered surfaces are physically spaced apart from one another, the effective diameter of the annular spacing  150  therebetween will be substantially equal to the inner diameter of the third wall portion  124  of the throughbore. Moreover, when the tapered surfaces are physically separated from one another, the length of the annular space therebetween is “maximized”.  
         [0028]    In the seal of the present invention, the throughbore of the plate and the central opening through the actuator/bearing component are in register and the lift rod  86  is received therethrough and reciprocates therein. In accordance with a further aspect of the present invention, there is provided a resilient member, such as an “O”-ring,  152  disposed within the annular space  150  between the facing tapered surfaces of the throughbore and the actuator/sealing component. This “O”-ring is chosen to having an inner diameter which is greater than the outer diameter of the lift rod  86  which passes through the plate and the actuator/sealing component, and it encircles the lift rod reciprocating therethrough such that when the “O”-ring is relaxed, it does not engage the outer circumference  154  of the lift rod  86 . To ensure this effect, the inner diameter of the third wall portion  124  of the throughbore of the adapter plate is chosen to be at least equal to, or greater than, the outer diameter of the “O”-ring  152  when the “O”-ring is in its relaxed state. Further, the cross-sectional diameter of the “O”-ring is chosen to ensure that when the “O”-ring is relaxed, its outer surface will engage both of the tapered surfaces  122  and  140  thereby tend to move the adapter/sealing component  130  away from the tapered surface  122  of the throughbore, but without causing the inner circumference of the “O”-ring to engage the outer circumference of the lift rod. Generally, it is desired that the relaxed “O”-ring substantially fill the annular space between the tapered surfaces, but without the “O”-ring engaging the outer circumference of the lift rod.  
         [0029]    The seal  100  further includes a piston member  160  which is generally of a hollow cylindrical geometry having a top annular surface  161  and is disposed in encircling relationship to the lift rod  86 . The internal diameter of the piston member is chosen to provide at least partial alignment for the lift rod  86 , while permitting free sliding movement between the piston and the lift rod. The outer circumference of the piston member is provided with first and second circumferential flanges  162 ,  164  disposed approximately midway between the opposite ends  166 ,  168  of the piston member and which are spaced apart from one another to define an annular channel  170  therebetween for the receipt therein of an annular sealing member  172 , such as an “O”-ring.  
         [0030]    As depicted in FIGS. 8, 9 and  11 , the piston member is reciprocatably mounted within a housing  180  having a generally central opening  182  which extends between the top and bottom surfaces  184 ,  186  respectively of the housing. This opening is geometrically complementary to the outer circumferential geometry of the piston member to the extent that the piston member will reciprocate within the opening through the housing. To this end, the opening  182  through the housing includes an annular seal  184  disposed in a circumferential groove  186  in that portion of the inner wall of the housing adjacent the top surface of the housing. This seal  184  engages the top portion of the outer circumference of the piston member to provide fluid-tight sealing therebetween (FIG. 2). Between this seal  184  and the bottom  186  of the housing, the inner circumference of the opening through the housing slidably receives therein the circumferential flanges  162 ,  164 , and the seal  172  captured therebetween, to define a fluid-tight annular chamber  188  between the seal  172  and the seal  184  associated with the top end of the piston.  
         [0031]    Referring to FIGS. 10 and 11 the bottom  186  of the housing  180  is fitted with a closure plate  190  having a central opening  192  that is in register with the opening  182  through the housing  180 . In the depicted embodiment, this bottom plate is removably mounted to the bottom surface of the housing as by bolts  191 ,  193  or other appropriate fasteners (FIG. 11). In the depicted embodiment, this bottom plate includes an annular projection  194  on the top surface  196  thereof which is provided with an annular seal  198  about its inner circumference. This annular projection is adapted to be received within that portion of the opening  182  adjacent the bottom  186  of the housing  180 , and to receive the bottom end  168  of the piston  160  within its opening  192  with the annular seal  198  disposed between the outer circumference of the bottom end  168  of the piston  160  and the inner circumference of the opening  192  of the bottom plate  190 . By this means, there is defined a further fluid-tight annular chamber  200  between the seal  172  associated with the flanges on the piston member and the bottom portion of the opening  182  through the housing  180 .  
         [0032]    Access to this further chamber  200  for purposes of the admission of pressurized fluid from a source  202  thereof located external of the housing is provided via an inlet port  204 . An outlet port  206  is provided through the housing wall to provide for fluid communication from within the chamber  188  that is adjacent the top surface of the housing and on that side of the seal established at the circumferential flanges of the piston member, thereby permitting pressurized fluid admitted into the further chamber  200  to urge the piston upwardly within the housing  180  and to permit the influx of ambient atmosphere upon movement of the piston member downwardly within the housing.  
         [0033]    The housing  180 , with its bottom plate  190  affixed thereto is adapted to be mounted to the seal adapter plate  102 , or by bolts or other fasteners (not shown) in a position whereby the top annular surface  161  of the piston may engage the annular bottom surface  134  of the actuator/bearing component and to provide a force against the actuator/bearing component which will urge the actuator/bearing component toward the tapered surface portion  122  of the inner wall of the adapter plate.  
         [0034]    In the operation of the seal  100  of the present invention, at all times when the lift rod  86  which reciprocates through the seal is functioning, as established by the controller  210  for the packaging machine, no pressurized fluid is present in the chamber  200  within the housing  180 . The absence of such pressurized fluid permits the piston member to be moved downwardly within the housing. Downward movement of the piston member is effectuated by means of the expansion of the “O”-ring disposed between the tapered surfaces of the throughbore  116  and the top surface  140  of the actuator/sealing component. That is, when there being no pressure applied via the piston member to the adapter/sealing component, the adapter/sealing component is free to move downwardly within the throughbore of the adapter plate. Under these circumstances, the “O”-ring is free to assume its relaxed state. The expansion of the “O”-ring to its relaxed state urges the adapter/sealing component and the piston member downwardly, maximizing the annular space within which the “O”-ring is disposed and the “O”-ring expands into disengagement with the lift rod passing through the seal. So long as the packaging machine is functioning to fill and seal cartons, the “O”-ring is free of engagement with the lift rod so that there is minimum, if any, wear and tear upon the “O”-ring.  
         [0035]    Upon shut-down of the operation of the packaging machine, for instance to the end of a shift or the like, the controller  210  provides an appropriate signal to the source  202  of pressurized fluid, commonly air, to effect admission of pressurized fluid into the chamber  200  defined within the housing. This pressurized fluid urges the piston member upwardly within the housing, causing the top end  161  of the piston member to engage and urge the adapter/sealing component upwardly within the throughbore in the adapter plate. This action causes the tapered surface of the adapter/sealing component to engage the “O”-ring and urge this “O”-ring to move upwardly toward the tapered surface defined by the second wall portion  122  of the throughbore of the plate. This movement of of the “O”-ring causes the “O”-ring to become captured between the facing oppositely tapered surfaces and thereby compressed diametrically and circumferentially. This compression of the “O”-ring causes the “O”-ring to sealingly engage the outer circumference of the lift rod about which the “O”-ring is disposed and close off, fluid-tight, the bottom of the enclosure at the location of the passage of the lift rod through the bottom wall of the enclosure. This seal between the lift rod and the bottom wall of the enclosure remains until the controller for the packaging machine sends an appropriate signal to the source of pressurized fluid to cease the introduction of pressurized fluid into the chamber. Upon such cessation of the application of pressurized fluid to the chamber, the piston becomes free to move, thereby removing the compressive force against the “O”-ring and permitting the “O”-ring to seek its relaxed state. As the “O”-ring returns to its relaxed state, it expands and forces the adapter/sealing component downwardly and away from the tapered surface of the second wall portion of the throughbore, which, in turn, urges the piston downwardly within the housing. Further, the expansion of the “O”-ring to its relaxed state disengages the “O”-ring from the outer circumference of the lift rod  86 .  
         [0036]    Whereas the present invention has been described in specific terms for purposes of clarity and understanding, it will be recognized by one skilled in the art that various modifications and/or alternatives may be employed without departing from the substance of the invention. It is intended, therefore, that the present invention be limited only as set forth in the claims appended hereto.