Abstract:
An improved aerosol container filling adapter has a chamber seal engaging the bottom of a valve cup on the container. A chamber in the adapter is pressurized to open an aerosol valve and to fill the container. Pressure reduction in the chamber allows the aerosol valve to close, independent of the seal, and without content “spit-back”. Alternative structures and methods are disclosed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to filling of aerosol containers and more particularly to adapters for filling aerosol containers with gases.  
           [0002]    When aerosol containers or cans are filled with whipped cream, for example, it has been desirable to inject the cans with precise amounts of nitrous oxide propellant which gives the cream a foamy quality. Typically, this is done through a filling adapter designed particularly for the style of aerosol valve or valve tip used in the can. It is advantageous to operatively seal the adapter to the valve stem, valve tip or stem island so that no (or only a little) gas is wasted during the injection process. In this regard, past adapters have usually sealed onto the can&#39;s valve stem, the valve tip which mounts on the stem or onto the projecting island through which the valve stem exits the can. These seals facilitate injection of the gas or propellant into the can.  
           [0003]    While such systems have worked for years, they have certain inherent disadvantages to overcome. For example, one major disadvantage is that of “spit back”, where some of the cream is spit out of the valve stem and/or valve tip at the end of the gas injection process. In most, if not all, instances, this occurs where the fill is completed but the valve in the can is held open by the adapter, allowing the residual vapor pressure in the can to spit back cream. In particular, where the adapter seals on the valve tip or stem, for example, the can valve is held open at least momentarily at the end of the fill cycle by the adapter seal and the expanding whipped cream in the can spits out or sputters out. In order to meet sanitation requirements, the so-filled cans must be washed to remove all means from the actuator tips.  
           [0004]    Accordingly, it has been one objective of the invention to provide an improved adapter for allowing gas injection yet obstructing “spit back” from an aerosol can or container.  
           [0005]    Another objective of the invention has been to eliminate “spit back” in filling of aerosol cans.  
           [0006]    Another objective of the invention has been to provide improved methods of filling aerosol cans without “spit back”.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    To these ends, the invention in a preferred embodiment provides an adapter for filling an aerosol container wherein the adapter seals not to the valve stem, valve tip or valve island in the valve cup through which the stem extends, but rather onto the valve cup itself. Thus, neither the adapter nor its seal interferes with the valve stem or valve tip and the corresponding valve is not in any way impeded from closing when the filling cycle ends.  
           [0008]    Specifically, this is accomplished by an improved adapter having a seal which is presented to a portion of the container or can such as the base of the valve cup structure on the end of the aerosol can. Typically, the valve cup is of pressed metal in cup-shaped configuration and defining on its center the valve island or boss-like projection through which the valve stem protrudes. Ideally, the can aerosol valve is disposed within the valve island.  
           [0009]    In use, the adapter according to the invention has an end seal which seals on the floor of the valve cup. The head space defined by the adapter above the valve is pressurized with the desired gas or propellant. This pressure forces the aerosol valve open, allowing filling to begin.  
           [0010]    Preferably, the gas or propellant is supplied to the adapter from a metering cylinder which precisely controls the quantity of propellant being filled. When the piston of the metering cylinder completes its injection stroke, the pressure inside the aerosol can and the pressure above the valve in the adapter will be equalized and the spring-loaded aerosol valve will immediately close. The aerosol valve is free to close immediately on pressure equalization since there is no interference with the valve tip or valve stem by any seal of the adapter. This action prevents “spit-back” of the cream after propellant filling, eliminating the need for cleaning the container before final packing.  
           [0011]    In addition to avoidance of “spit-back”, the invention herein provides a yet further advantage. Specifically, it allows filling of aerosol cans with many different valve stem and valve tip configurations with the same universal adapter. Prior to the invention, the adapters generally were required to conform., at least in their seal structure, to the specific configuration of the valve stem or valve tip. According to the invention, the seal is accomplished on the floor of the valve cup of the container which is generally uniform across a wide variety of aerosol applications independent of the specific stem or tip structures used. One adapter design then, according to the invention, has widely varying applications across a wide range of aerosol valve stems and tips.  
           [0012]    Moreover, it will be appreciated that the preferred embodiment of the adapter according to the invention can be modified to seal on the curl, sides or other bottom structure of the valve cap while still providing the benefits and advantages noted above.  
           [0013]    These and other advantages and modifications will be readily apparent from the following detailed description of a preferred embodiment of the invention, and from the drawings in which: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a cross-sectional view of a preferred embodiment of an adapter according to the invention;  
         [0015]    [0015]FIG. 2 is a cross-sectional view of the adapter of FIG. 1 showing lowering of the adapter of FIG. 1 toward a filling position with the poppet being opened by the motion;  
         [0016]    [0016]FIG. 3 is a cross-sectional view of the adapter of FIG. 2 showing the condition of the adapter upon filling with the aerosol valve tip depressed by filling pressure and the aerosol valve opened;  
         [0017]    [0017]FIG. 4 is a cross-sectional view of the adapter of FIG. 3 showing the end of the filling cycle with poppet valve still open, but the valve tip released upwardly to close the aerosol valve;  
         [0018]    [0018]FIG. 5 is a cross-sectional view of a prior art adapter in a position corresponding to that of the adapter in FIG. 1;  
         [0019]    [0019]FIG. 6 is a cross-sectional view of the prior art adapter of FIG. 5, but showing the adapter in a position corresponding to that of the adapter of FIG. 4, but with the valve tip still held in a depressed condition; and  
         [0020]    [0020]FIG. 7 is a cross-sectional view like FIG. 6, but showing the aerosol valve clogged upon pressure equalization even though the poppet is open. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Turning now to the drawings, there is shown in FIGS.  1 - 4  a preferred embodiment of an adapter  10  according to the invention. Adapter  10  includes an adapter holder  11 , adapter housing  12 , an adapter body  13  and a retainer  14 . The holder  11  is mounted in housing  12  by means of cooperating threads  15 , and an O-ring seal  16  seals holder  11  and housing  12 .  
         [0022]    A spring-biased poppet valve  20  is disposed in bore  21  of holder  11 . Poppet  20  includes a gas passage  22  and transverse gas passages  23  communicating with passage  22 .  
         [0023]    A teflon seal  26  is disposed on an annular seal retainer  27  having a circular projection  28  supporting seal  26 . Retainer  27  is mounted on shoulder  29  in bore  30  of housing  12 .  
         [0024]    Poppet face  24  of poppet  20  removably seals on seal  26  as shown in FIG. 1, from pressure by poppet spring  25 , so that no gas pressure above the poppet  20  can flow therepast.  
         [0025]    Adapter body  13  includes a poppet engaging projection  32  having relieved areas  33  (FIG. 3). As will be described, poppet  20  can be unseated from seal  26 , against the bias of spring  25 , by motion of body  13  and projection  32  against the poppet  20 . When the face  24  of poppet  20  is lifted from seal  26 , pressurized gas in bore  21  above the poppet can flow through passages  22 ,  23  and enlarged annular chamber  31  in bore  21  of housing  12 , around face  24 , between face  24  and seal  26 , through relieved areas and into open bore  35  of projection  32 . If desired, a seal  19  can be used between projection  32  of the housing  12  to prevent gas leakage therearound (i.e. in seal area  36 ).  
         [0026]    Retainer  14  has an inwardly turned flange  38  fitting over flange  39  of housing  12  to prevent its separation therefrom. Retainer  14  also has an internal inwardly directed circular flange  41  fitting in groove  42  of body  13  to secure it to housing  12 . At the same time, flange  38  can ride on outer surface  43  of housing  12  so the body  13  can be moved in a direction into the bore  44  of housing  12  toward poppet  20 .  
         [0027]    The interior wall or bore  46  of body  13  is preferably shaped similarly to a valve tip  50  extending from an aerosol can as will be described. Preferably interior bore  46  of body  13  closely conforms to the shape and size of anticipated tip  50 , but it will be appreciated bore  46  can accommodate many tip sizes and configurations. The closer the shape and size of bore  46  to the tip, the less headspace for excess gas, a desirable feature.  
         [0028]    A seal, such as an O-ring seal  47 , is disposed in an end face  48  of body  13 . End face  48  defines a groove  49  for seal retention.  
         [0029]    It will be appreciated that adapter  10  is mounted on a gas filling apparatus (not shown) provided with a metered pressure source of any suitable manufacture for pressurizing the adapter  10  with a precise volume of gas at a defined pressure for filling aerosol containers. The adapter  10 , for example, is mounted via holder  11  in or on a reciprocating apparatus for moving the adapter toward an aerosol container, holding the adapter  10  for movement of an aerosol container toward the adapter  10 . Of course, the source of pressurized gas is operably connected to bore  17 , in holder  12 , communicating with bore  21 .  
         [0030]    Adapter  10  is useful in filling aerosol containers or cans with pressurized gas for propellant or other applications, such as foaming of the container contents such as whipped cream. In particular, an aerosol container or can  52  is illustrated in FIG. 1. Can  52  has a domed top  53  and a valve cup  54 . Valve cup  54  includes a circumferential curl  55 , interior sides or walls  56 , a bottom wall  57  and a central projection, boss or “island”  58 . An aerosol valve  59  (not shown in detail), is typically disposed at least partially within the island  58  and is provided with a valve stem  61  extending therefrom through island  58 . Valve stem  61  carries valve tip  50  which can be pushed downwardly toward aerosol valve  59  to open the valve via movement of stem  61 .  
         [0031]    It will be appreciated that tip  50  may typically have a circumferential flange or skirt  51  surrounding the island  58  and movable or reciprocable thereon. So, as tip  50  is urged toward aerosol valve  59  (FIG. 3), skirt  51  moves over the island  58  as illustrated in the Figs. Of course, tip  50  has a slotted end  50   a  for dispensing of the contents, such as whipped cream, therefrom under the pressure of a propellant such as a gas. Nitrous oxide (NO) is typically used: it also promotes foaming of the whipped cream product.  
         [0032]    Operation of the invention is illustrated in the sequence of FIGS.  1 - 4 . In FIG. 1, the adapter  10  is placed onto a can  52  either by introduction of the adapter  10  to the can  52  or of the can  52  to the adapter  10 . Typically, cans  52  are introduced to a carousel (not shown) of mounted adapters  10  which are sequentially urged toward the cans  52 .  
         [0033]    As the adapter  10  is moved onto the valve cup  54 , seal  47  engages the bottom wall  57  of cup  54  and seals against that wall. End face  48  forms a stop, engaging wall  57  to limit compression of the seal so it is not overly stressed. At the same time, it will be appreciated that tip  50  has been received in bore  46  freely (FIG. 2), and without such engagement as would move tip  50  to open the aerosol valve  59  in can  52 . Thus, the lower end of the adapter is sealed to the valve cup bottom wall  57 . Alternately, the seal  47  could be positioned on the lower end of body  13  so that it sealed onto the side wall  56  or on curl  55  of the cup  54 . Given enough room, it may even be alternately sealed onto island  58 . Preferably the seal is accomplished on bottom wall  57  as shown.  
         [0034]    After sealing, the adapter  10  is pushed toward the can  52 . See FIG. 2. Since the body  13  is stopped from further motion by end face  48 , the housing  12  continues to move toward the can  52 . This motion urges plate  24  of poppet  20  onto the upper relieved end of projection  32 . Continued motion overcomes the bias of spring  25  and the poppet is moved off seal  26  (FIG. 2). This effectively opens chamber  31  to bores  23  and  22  of poppet  20 , and through them to open bores  21  and  17  of holder  11 .  
         [0035]    Comparing FIGS. 2 and 3 it will be appreciated that body  13  is fully seated in both, yet tip  50  in FIG. 2 is not yet depressed to open valve  59 . FIG. 3 shows tip  50 , depressed by pressure, to open valve  59 .  
         [0036]    When a preferably precise metered volume of a gas propellant such as Nitrous Oxide (NO) is metered into passage  17  and thus to chamber  31  and into bore  46  of body  13 , the pressure in bore  46  is sufficient to move valve tip  50  (and thus stem  61 ) toward the aerosol valve  59  to open it so the gas is injected through valve  59  into can  52 . Propellant fill is thus initiated as illustrated in FIG. 3.  
         [0037]    Once the pressure above adapter  10  and in can  52  is equalized, the filling is complete. At this time, gas pressure differential is lost, and the spring biased aerosol valve  59  closes, preventing any back flow or “spit back” of its contents, even though poppet  2  is still open (the metered gas pressure is now equalized) (FIG. 4). In FIG. 4, it will be appreciated that the spring bias of aerosol valve  59  is sufficient to raise tip  50  in chamber  46 , the pressure being equalized, to close the valve  59 . There is no seal drag on tip  50 , and no spit-back. The adapter is then lifted from the can  52 , closing poppet  20  for a repeat operation on a subsequent can  52 .  
         [0038]    A significant benefit of the above described invention can be appreciated from an understanding of the prior art adapter  64  as depicted in FIGS.  5 - 7 . In these Figs., components similar to those of the above described invention are identified by the same numbers, while different components have different numbers. In essence, the major differences lie in the adapter body which, in the prior art, is defined by two separate members, upper body  65  and lower body  66 . An O-ring seal  67  is oriented between the two components  65 ,  66  of the adapter body.  
         [0039]    In use, when the adapter  64  is introduced to a valve cup  54  (FIG. 5), the lower adapter member  66  and/or retainer ring  14  engage the valve cup  54 . Further motion toward the valve cup causes upper adapter body  65  to move toward lower adapter body  66 , squeezing seal  67  against valve tip  50  and sealing the adapter, not to the valve cup  54 , but to tip  50  (FIG. 6). Continued motion down plus the pressure of the propellant introduced into the adapter, moves tip  50  down to open aerosol valve  59  for filling (FIG. 6). Once poppet  20  opens and the desired propellant is injected through the adapter  64 , pressure is equalized. Since, however, seal  67  is effected against the tip  50 , it drags on the tip  50  and the tip  50  is not free to move and is held in its downwardly position, holding open valve  59 , even though the adapter is slightly retracted poppet  20  is seated (FIG. 7). This is evident in FIG. 7 showing the continued depressed state of tip  50 . Contents of can  52  now mixed with propellant, spits back through valve  59  and out of tip  50  until the adapter  64  is further lifted away from tip  50 , releasing it from seal  67  and allowing valve  59  to close. Thereafter, the tip  50 , valve cup  54  and/or can  52  must be cleaned before final packing.  
         [0040]    Accordingly, it will be appreciated that the invention seals, not on tip  50 , but on valve cup  54  and avoids spit-back. Moreover, since the seal is not required on the tip  50  which is more likely to vary in configuration than the valve  54 , the adapter  10  of the invention is capable of serving a wide range of aerosol filling operations, without modification, to accommodate varied tip configuration and size.  
         [0041]    These and other alterations and modifications will become readily apparent to those of ordinary skill in the art without departing from the scope of the invention and applicant intends to be bound only by the claims appended hereto.