Abstract:
A process and machine for refilling and reusing or recycling spent “bag on valve”-type aerosol cans. The process includes drawing a premeasured amount of liquid product into a refilling module, followed by pushing the product into the product bag (that surrounds the bag on valve), acting against the pressure of the gas already in the can. Opposite-acting, one-way valves in the inlet and outlet of the refilling module enable the drawing and pushing action. One size or type of refilling module is easy to swap with another.

Description:
TECHNICAL FIELD   
       [0001]    The present invention relates to a specific type of aerosol can that uses a valve called the “bag on” valve. More specifically, the invention described and claimed here relates to an improvement that enables “bag on” valve aerosol cans to be refilled and/or reused rather than discarded after a one-time use. 
       BACKGROUND  
       [0002]    Bag on valve cans are significantly different from conventional aerosol cans in that they physically separate the product to be dispensed (“dispensed product”) from the propellant gas. The dispensed product is self-contained within a flexible bag inside the can, surrounded by the propellant gas (gas that is under pressure). The pressure of the propellant gas squeezes the bag when the valve is open, pushing the dispensed product through the valve and then typically out through a spray nozzle. 
         [0003]    Other aerosol cans typically do not use gas to propel the product in the same way. Today, it is common to use liquid hydrocarbon fluids or other highly volatile fluids in aerosol cans that are mixed with the can&#39;s product in the same interior space (the product might be a chemical like a glass cleaner, for example). In some cases pressurized gas like nitrogen or carbon dioxide is used, with the gas sitting in the top portion of the can and the liquid sitting below. The liquid product covers the end of a straw-like outlet tube. The pressure of the gas above pushes the liquid down and then back up through the tube when the can&#39;s valve is pushed open, usually by depressing a spray nozzle. 
         [0004]    All of these designs are well-known. However, the “bag on” design is environmentally friendly because the propellant gas never exits and remains sealed in the can after product discharge. The basic “bag on” design involves a valve that is connected to a rolled up bag (rolled up before filling). The valve/bag arrangement is inserted into a canister-type container (“the can”) and the region surrounding the bag, inside the can, is permanently pressurized with a gas, like nitrogen. After this is done, the liquid product is pumped into the empty bag, through the valve, thus unfurling and filling the bag against the pressure of the gas inside the can—with the gas functioning as a propellant gas that pushes against the outside of the bag&#39;s wall. The valve is opened in the same way as conventional aerosol cans to spray out the product, but with the propellant gas squeezing the liquid product bag and ejecting product through the opened valve and a spray nozzle. 
         [0005]    However, once the product in the “bag on” can is fully discharged, the can remains pressurized with the collapsed bag inside. And it remains pressurized during the course of being discarded or recycling the metal that is used to make the can&#39;s walls. At some point in time during that process, the pressurized gas is released. 
         [0006]    The problem with bag on valve cans is that they require highly sophisticated and expensive machines to fill them—which is done on a mass production basis. These machines commonly use metered pumps to fill the bag inside the can after pressurization, with the pump running a certain amount of time to fill each can to the appropriate level, in sequence, one after another. Pressurization and sealing of the propellant gas in the can is done as part of the same process. 
         [0007]    Because of the complexity of these filling machines, they are usually installed in locations where manufacturers are filling large numbers of cans and then shipping them out for distribution. It is also not easy to do line changes with these machines (that is, filling cans with one type of product and then switching to another) because of machine cleaning requirements. As a consequence, no one has recognized that bag on valve cans could be refilled and reused if an economical and efficient means was developed to refill cans in the field, in lieu of collecting cans in the distribution network and returning them to a filling machine location. 
         [0008]    The present invention provides a simplified process and machine that enables a small business to cheaply refill bag on valve cans on-site. As an example, the automotive industry uses large numbers of bag on valve cans for brake cleaning fluid or other kinds of oils or solvents. A typical automotive shop might buy and discard cans by the case, as consumables, during the normal course of doing auto repair work. The present invention allows the shop to easily refill the cans on site—which means the shop only needs to buy replacement product in bulk and not individual cans that are prefilled, thus providing a means for reducing overall costs over time. 
       SUMMARY  
       [0009]    The invention or inventions disclosed in this document relate to a process and machine for refilling an empty liquid product bag inside a bag on valve can (sometimes called the “container” or “dispensing container”). The dispensing container has a certain volume of pressurized gas that collapsed the bag (“the liquid product bag”), on the “bag on” valve, during the course of spraying product from the can. 
         [0010]    According to the present disclosure, the can or container is coupled to a liquid product refilling chamber of an apparatus, with the refilling chamber containing a measured amount of liquid product that is to be used to refill the collapsed liquid product bag. The liquid product is delivered into the refilling chamber before coupling the can, although there may be ways of altering the sequence. Once coupled, however, the measured amount of liquid product is pushed into the liquid product bag from the refilling chamber, at a sufficient pressure to counteract the pressure of the gas inside (surrounding the product bag), thus inflating the liquid product bag (with the product) against the pressure of the gas. The can is decoupled after refilling is completed. 
         [0011]    Preferably, the liquid product is delivered into the refilling chamber via a “drawing” action, similar to a vacuum effect, although there may be other ways of putting product into the chamber. It might be possible to push the product into the chamber by an external pump, for example, during the course of the filling action. Either way, the refilling chamber is preferably constructed as a swappable module that houses a reciprocating piston. When the piston retracts inside the chamber, it allows liquid product to be drawn into the refilling chamber through a one-way check valve or one-way inlet. The size of the chamber is defined by the diameter of the piston and the linear distance of its travel, back-and-forth. 
         [0012]    Reversing direction of the piston causes it to push the liquid product out from the refilling chamber, through a needle valve mechanism, and into the liquid product bag. The needle valve mechanism also has a one-way flow control design that operates opposite to the one-way inlet. In other words, when the one-way inlet into the refilling chamber is “open,” during the drawing and filling process summarized above, the one-way flow mechanism in the valve mechanism is closed. Reversal of the piston&#39;s direction causes these functional directions to switch as well. 
         [0013]    The piston in the liquid refilling module is driven by an air pump mechanism. According to the design disclosed below, one possible version of an air pump mechanism consists of an independent air-driven piston member that reciprocates back and forth by using an air valve mechanism to create high/low pressure differentials on each side of the air piston. 
         [0014]    Because it is swappable, one size of liquid filling module can be exchanged with another. This would be done to accommodate different sizes of the liquid product bag for different cans or when it is desired to put different kinds of liquid products (typically different chemicals) in different cans. Swapping modules reduces time spent in cleaning lines when the same machine is used to put different product into different cans. 
         [0015]    The foregoing summary will become better understood after reviewing the accompanying description below and the accompanying schematics. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    In the drawings, like reference numbers refer to like parts throughout the various views, and wherein: 
           [0017]      FIG. 1  is a frontal view of a filling machine for a bag on valve can that is constructed according to the invention described here; 
           [0018]      FIG. 2  is a view like  FIG. 1 , but illustrates a portion of the machine that is the swappable liquid product refilling module; 
           [0019]      FIG. 3  is a schematic that illustrates operation of the liquid product refilling module illustrated in  FIG. 2 ; 
           [0020]      FIG. 4  is a view like  FIGS. 1 and 2 , but illustrates an air piston pump mechanism for operating the liquid product refilling module illustrated in  FIG. 2 ; 
           [0021]      FIG. 5  is a view of a portion of the machine that provides a base for resting the can during a filling operation and pushing the can into coupling registration with a needle valve mechanism; 
           [0022]      FIG. 6  is a view of a portion of the machine that is the needle valve mechanism for providing a filling needle for the empty bag on valve can; and 
           [0023]      FIG. 7  is an exploded view of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Referring now to the drawings, and first to  FIG. 1 , shown generally at  10  is a filling machine designed to refill “bag on” valve aerosol cans. The machine consists of several different portions, each of which will be described in series below. 
         [0025]    First, the lower portion of the machine has a base, indicated generally at  12 , for creating a support for holding the can  14  during the filling operation (The can  14  is schematically shown in  FIG. 3  and indicated in dashed lines in  FIG. 1 ).  FIG. 5  better illustrates the base portion  12  of the machine  10 . Directing attention there, the can  14  sits on a spring-biased platform  16 . The platform  16  is connected to the upper end of a shaft  18 . The lower end of the shaft  18  carries a piston  20  that is within a cylindrical chamber, indicated generally at  22 . 
         [0026]    When the can  14  is placed on the platform  16  (see  FIG. 1 ), the can occupies the lower area (generally indicated by arrow  24  in  FIG. 1 ) of the machine  10 . All of the stages and sequencing of the refilling process are described below, but one stage involves lifting the can  14 . Focusing on  FIG. 5  for the time being, pressurized air is injected into the chamber area (indicated by arrow  26  in  FIG. 5 ) below the piston  20 . This drives the piston  20  upwardly (in the direction indicated by arrow  27 ) against the bias of spring  30  that is coiled around shaft  18 , for the purpose of vertically raising the can  14 . The delivery of pressurized air can be handled in different ways. Arrow  28  indicates a suitable connection port to an air source. This is a simple valve-operated arrangement that allows chamber  26  to be pressurized for lifting and then vented to allow spring  30  to return the platform  16  to its initial position. 
         [0027]    During the coupling stage of the filling operation (which is also described in greater detail later), the can  14  is placed on platform  16  and piston  20  ( FIG. 5 ) is driven upwardly. Before the piston  20  is actuated, however, the can  14  is positioned correctly via machine guide structure. In other words, in order to be refilled, the can  14  needs to be brought into registration with or coupled with a needle valve mechanism (described below) for refilling the can. The needle needs to align with the can&#39;s “bag on” valve structure. This means that the can  14  has to be located and properly aligned in the machine  10 , and held in the same aligned position, as it is raised by platform  16 . The can  14  cannot be allowed to move a large distance, off-axis, during the filling process 
         [0028]    There are different ways of creating can-guiding structure that can perform the needed alignment/holding function described above. In the present design, and referring now to  FIG. 1 , the machine described here has a guide structure that generally follows the outer circumference of the can  14 . The location of the guide structure is generally indicated at  32 . However, the guide structure  32  could take different forms and still perform the same function. In this respect, it could be a half-moon shaped scallop (where arrow  32  points) in a support  34  that extends between opposite sidewalls  36 ,  38  of the machine  10 . Looking at the machine  10  frontally, the user places the can  14  on the platform from the front, against the scallop or guide structure  32 , and the can is close to the aligned position or place it needs to be during the filling operation. The guide structure  32  then helps keep the can  14  on-axis as it is lifted and slides upwardly along the guide structure by air-actuation of piston  20  (in  FIG. 5 ). 
         [0029]    While it may be possible to change operational sequences, before the can  14  is lifted into position for refilling, the machine has a liquid refilling module that is loaded with a measured amount of liquid product that is to be put into the can  14 . The liquid refilling module portion of the machine is generally indicated at  40  and illustrated, specifically, in  FIG. 2 . 
         [0030]    Directing attention to  FIG. 2 , the liquid refilling module  40  has a lower part  41  that defines a collar (hereafter “collar  41 ” or “collar part  41 ”) for guiding and holding the can  14  during the refilling process. In essence, the collar  41  includes a circular recess and bore, indicated by lines  44  that is shaped to register with the top neck/shoulder portion of the can  14  when it is lifted into contact with the collar part  41 . This is also schematically illustrated in the lower portion of  FIG. 1 . 
         [0031]    Before specific details of the filling operation are further described, and as was generally described earlier, it should be appreciated that the liquid refilling module  40  is designed to be a fully “swappable” unit to and from the machine  10 . Referring back to  FIG. 1 , to describe this point, the module  40  is a cylindrical unit having a rectangular top plate  42 . The top plate  42  makes it possible for the entire module  40  to be adapted to slide in and out from the machine  10 , from the front. The module  40  has a drive shaft  48  (further described below) that passes laterally through a slot  50  in the machine&#39;s top panel or top plate  52 , during module swapping. Two side brackets  44 ,  46  accommodate the sliding action of the module&#39;s top plate  42 . While not shown in the drawings, the brackets  44 ,  46  work in conjunction with a back stop (mounted to machine top plate  52 ) that stops the module  40  in the proper location, when it is slid into place. At that point, it is also in the proper position relative to the guide structure  32  below and previously described (for guiding the can  14  up to the liquid filling module  40 . 
         [0032]      FIG. 2  focuses on illustrating the operation of the liquid refilling module  40 , and its relative position in the machine  20 , without the side brackets  44 ,  46  just described. The module  40  has cylindrical walls, generally indicated at  54 . The cylinder  54  is closed at the top by the rectangular top plate  42  described above and at the bottom by another plate  56 . The lower plate  56  has an orifice or inlet  58  that leads into a passageway through the body of the lower plate  56  and opens upwardly into the region immediately below a hydraulic piston  60 . The inlet is connected to a reservoir  62  that contains the liquid product that is used to refill the can  14 . In  FIG. 3 , the reservoir  62  is labeled “liquid product.” This is further described below—and attention is now directed to  FIGS. 2 and 3  together. 
         [0033]    The area below piston  60  defines a product refilling chamber. When the piston  60  is in the position shown in  FIG. 2  (and the upper portion of  FIG. 3 ), the volume of the refilling chamber is essentially zero. The piston  60  is a reciprocating member or, in other words, it moves back and forth as schematically illustrated in  FIG. 3 . It is to be appreciated that, while the machine  10  is generally an arrangement of vertical parts,  FIG. 3  shows the parts laid down horizontally so that the reader can understand how the piston  60  is driven and how it works to fill the can  14 . 
         [0034]    The piston  60  is moved up (vertically) by an air pump mechanism portion of the machine, shown generally at  62  in  FIGS. 4 and 3 . The air pump mechanism  62  is double-acting and driven by a combination of valve and air compressor system illustrated, respectively, at  64 ,  66  in  FIG. 3.The  compressor system  66  can consist of a shop compressor system, conventional air compressor, or the like. The valve would be well-known and easy to obtain off-the-shelf based on the description set forth here. 
         [0035]    Referring to the upper right-hand corner of  FIG. 3 , the valve  64  is first operated to pressurize the left-hand side of an air piston  68  in the air pump mechanism  62 . Arrow  70  generally indicates the direction of airflow. At the same time, the region to the right of air piston  68  is allowed to vent via the valve mechanism  64 . This drives the air piston  68  in the direction indicated by arrow  72  in the upper right-hand portion of  FIG. 3 . 
         [0036]    The air piston  68  is connected to a shaft  74  that slides through a plate  76  that defines the bottom part of the air pump mechanism  62 . Similar to the refilling module  40  previously described, the air pump mechanism  62  has a cylindrical housing  78 , closed at the top by plate  80  and at the bottom by plate  76  just described. 
         [0037]    The shaft  64  is connected to the shaft  48  on the liquid refilling module  40  via a removable pin  82  or the like (see  FIG. 1 ). This connection causes the piston  60  in the refilling module  40  to be pulled upwardly as the air piston moves from the left-to-right position illustrated in  FIG. 3 . Once again,  FIG. 3  illustrates these parts in horizontal position for the sake of describing the machine&#39;s operation, when normally everything would stand vertically, as shown in  FIG. 1 . 
         [0038]    As piston  60  inside the refilling module  40  moves, in the direction indicated by arrow  84  in the upper part of  FIG. 3 , it creates a vacuum effect or “draw” that pulls liquid from the reservoir  62  (to help the reader, the reservoir is identified by the legend “liquid product” in  FIG. 3 ). When the piston  60  is at its top-most position, the interior volume of the refilling chamber corresponds to the volume of the liquid product to be put into the can  14 . In other words, the displacement of piston  60  defines a measured amount of product for refilling the can  14  that is specific to the sizing of the piston  60  and cylinder walls  54  that make up the refilling module  40 . The product volume for refilling the can is pointed out by arrow  86  in the lower left-hand portion of  FIG. 3 . 
         [0039]    The definition of the term “liquid product” would be understood by anyone knowledgeable about bag on valve cans. It could be any type of liquid that is normally dispensed by a bag-on valve can. A penetrating oil or solvent might be an example. 
         [0040]    As illustrated in  FIG. 3 , the inlet  58  into chamber  86  is “one-way” and controlled by a check valve  88 . Therefore, when the direction of piston  60  is reversed (arrow  89  in the lower part of  FIG. 3 ), the inlet/check valve combination  58 ,  88  is closed. The reversal is accomplished by the air pump mechanism  62 . More specifically, valve  64  is operated to open air pressure to the right-hand side of air piston  68  while the left-hand side is vented. This drives air piston  68  in the direction indicated by arrow  90  in the lower right-hand portion of  FIG. 3 , thus driving piston  60  in module  40 , for the liquid module-filling operation. 
         [0041]    However, referring to the earlier description of the base structure illustrated in  FIG. 5 , before the direction of the pistons  60 ,  68  are reversed, the base portion  12  of the machine lifts the can  14  into position. At this point in the description, it is appropriate to describe the machine&#39;s can-filling needle valve mechanism, indicated at  92  in  FIGS. 6 and 7 . 
         [0042]    Directing attention there, the needle valve mechanism  92  also functions as a one-way check valve that closes when the liquid module  40  is filled. There are many different ways this can be done. However, when the can  14  is lifted, it comes into registration and couples with the needle  94  of the valve mechanism  92 . The can pushes against collar part  41  on the module  40  (see  FIG. 2 ). The collar part rides on a pair of vertical shafts  96 ,  98  that have springs  100 ,  102 . This arrangement enables the collar part  41  to be pushed upwardly against springs  100 ,  102  and, simultaneously, the needle  94  on the valve mechanism protrudes through the collar part  41 . As the can  14  couples with the needle  94 , the can also pushes the needle  94  up against the bias of a spring  104  inside the valve mechanism  92 . This serves to open the valve mechanism. In essence, the operation of the base  12  pushes the can  14  against the collar part  14  of the liquid refilling module  40  and contracts it relative to the module  40  structure that houses piston  60 . 
         [0043]    Referring now to the exploded view of the valve mechanism  92  illustrated in  FIG. 7 , this mechanism includes a housing  106  mounted to the lower or bottom plate  56  of the module  40 . The needle  94  has an annular member  108  with orifices  110 ,  112 . When the needle  94  is in the position shown in  FIG. 6 , the orifices are closed by an end plate  114  that is shaped like a washer. When the can  14  pushes the needle  94  upwardly against spring  104 , the orifices  110 ,  112  open and allow fluid to pass through annular member  108  and into conventional needle orifices (not shown) that feed liquid product into the needle  94 . 
         [0044]    To explain the above in terms of the sequence of filling the module  40  and then driving product into the can  14 , the valve mechanism  92  functions like a one-way valve that works oppositely to the one-way inlet into the module (items  58 ,  88  in the upper left-hand portion of  FIG. 3 ). In other words, before the can  14  is lifted, the valve mechanism  92  is in the position shown in  FIG. 6 . There is a fluid flow path, illustrated by arrow  116  in  FIG. 6 , that carries through a collar  118  in the upper part of the valve mechanism  92  that leads into a needle valve chamber  120 , in which spring  104  is retained. The spring  104  pushes the annular member  108  tightly against washer  114 , thus closing orifices  108 ,  110  while the module  40  is refilled. 
         [0045]    After the module  40  is refilled, then the can  14  is lifted into position. When the needle  94  enters the can, the can then pushes the needle (and annular member  108  upwardly, away from washer  114 . This opens orifices  110 ,  112  and allows the product to flow through the valve into needle orifice structure. Thus, according to the sequence described above, the liquid module  40  draws product into its refilling chamber via one-way inlet/check valve  58 ,  88 . The needle valve mechanism  92  is closed during that operation. The bag on valve inside the can  14  is also closed, which would be its normal state. Then, the base  12  lifts can  14  in a coupling action with needle  94 . This action pushes the valve mechanism  92  “open.” At the same time, the bag on valve inside the can is pushed “open.” At that point, the can  14  (the liquid product bag inside the can) is coupled to the refilling chamber of module  40  via the bag on valve that was initially built into the can. The direction of piston  60  is reversed and it pushes the liquid product through the bag on valve (product pressure created by the piston  60  opens the bag on valve) and into the empty product bag inside the can  14 , against the pressure of the propellant gas that is already there. When the travel of piston  60  is complete, the base  12  is allowed to retract, as described above, so that the refilled can  14  can be decoupled from module  40  and removed. That bag on valve inside the can closes to retain the product inside the can. 
         [0046]    The foregoing description is not intended to limit the scope of the invention. For example, the liquid filling module is described as a “draw” then “push” filling mechanism. It might be possible to fill the module in a different way with some sort of pump mechanism. Also, an advantage to swapping the module  40  is that a user can have one module that contains one kind of liquid product and, rather than clean the module to use a different kind, the user can instead simply swap in a different module. Commercial grade filling machines require cleaning when the product is changed. 
         [0047]    The above description sets forth a design that is under development and has not been released for marketing purposes. This means that the design could be changed during the reasonable course of developing a marketable machine. That means the mechanical structures described above could be altered that nevertheless follow the overall framework of the machine design described above. For this reason, the invention and scope of patent right is to be limited only by the claims that follow, the interpretation of which is to be done in accordance with the standard conventions of patent claim interpretation.