Patent Publication Number: US-10766647-B2

Title: Pressurizing aerosol cans

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Application No. 62/351,413, filed Jun. 17, 2016, the contents of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     The invention relates to systems and methods for filling and pressurizing a container for dispensing a product, and to the corresponding containers, and more particularly to containers that can be pressurized, such as by a consumer. 
     Many household products are dispensed from pressurized containers through a dispensing valve, which containers are generally referred to as “aerosol containers.” Conventional aerosol containers are usually pressurized by a volatile liquid propellant, which provides an adequate pressure for dispensing even after a portion of the product has been dispensed from the container. 
     When filling conventional aerosol products, a manufacturer fills a can with the product and promptly charges it with the volatile propellant. The filled can, in a ready-to-use form, is then shipped according to U.S. Department of Transportation rules. For example, container designs given a DOT-2Q designation must be rated to withstand 270 psi and container designs given a DOT-2P designation must be rated to withstand 240 psi. 
     Conventional aerosol containers may be configured such that, for example, the product and propellant are in contact, or the product is housed in a bag within the can while the propellant is housed outside the bag, or a piston separates the product from the propellant. An example of the latter is EarthSafe Dispensing Technology, marketed by Crown Cork and Seal. 
     Aerosol cans are moving towards non-hydrocarbon propellants using compressed gas for many reasons, such as regulatory hurdles, consumer pressure for environmental reasons, etc. But compressed gas aerosols suffer from several disadvantages, including:
         Internal can pressure decreases over time as the compressed air is depleted with use.   A significant volume of the container is required for the non-hydrocarbon propellant (roughly 40% in typical aerosol applications).   Unlike hydrocarbons which re-pressurize the container each time, the spray and/or delivery performance of compressed gas propellant based aerosols changes over time.       

     SUMMARY 
     An aerosol recharging system can pressurize the container with air or other gas to provide internal pressure at the desired level, both initially upon first receiving the unpressurized container and then again after initial use. The can is capable of being re-charged as many times as required to provide adequate internal pressure for effective dispensing until empty. A user, such as a post-purchase end-user, places the container on a charger and initiates a process in which an air pump or compressed gas canister pushes gas into the container to the designed pressure. The container may have a more durable grommet (compared to conventional grommets) or a valve to interface with the pressurization system and to allow initial pressurization and subsequent re-pressurization, as needed. The system may be employed for any product that is suitable for discharge by compressed gas propellants (creams, gels, fragrances, etc.). The compressed gas, such as air, nitrogen, carbon dioxide, and the like, can be conventional. 
     The aerosol container can be filled on an unpressurized filling line (at atmospheric pressure) much like a beverage filling line, and preferably is shipped at an atmospheric or near atmospheric internal pressure. For example, it may be advantageous for thin walled containers to provide some pressurization merely for stiffening the container structure during shipping. In this regard, “near atmospheric pressure” used herein refers to internal pressure that is insufficient for dispensing the product. 
     More information is provided in the Section below marked Claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Different embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  shows a cross section view of an example of an aerosol container having a grommet in its bottom. 
         FIG. 2  is a schematic of a charging station. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     An aerosol container includes a grommet or valve through which a compressed gas can be inserted. As illustrated in  FIG. 1 , an aerosol container  1  includes a body  30 , a cone  40 , a valve cup  70 , and a valve  5 . Body  30  includes a sidewall and a base  20 . 
     The base  20  defines a charging port or aperture  25 , through which propellant is inserted into the aerosol container  1 . The propellant (not shown in the figures) is a compressed gas, preferably compressed air. Base  20  defines a charging port or aperture  25 , through which compressed gas is inserted into the aerosol container  1 . The internal pressure is used to drive the product in the aerosol container  1  out of the valve  5 , when it is opened for use by a consumer. 
     Aerosol container  1  in the embodiment shown includes a bag  50  inside body  30 . Exemplary bag  50  has a sidewall  53  that includes ribs  55  around the circumference of the bag  50 . The inside of the bag  50  defines a product compartment and the space outside bag  50 , between the bag  50  and the body  30 , defines a compartment in which compressed gas resides, after it is introduced via the charging port  25 . The product, which is not shown in  FIG. 1 , can be any product suitable for dispensing in an aerosol container, such as creams, gels, fragrances, etc. 
     The compressed air compartment is sealed by bottom  20  and a grommet  26 . The present invention is not limited to a container having a bag, nor to the grommet or the location of the grommet shown  FIG. 1 . Rather, the present invention encompasses any container or valve structure that is consistent with or defined in the claims, including without limitation structures in which the compressed gas is in contact with the product and any configuration (such as a piston, bag, and the like) in which the compressed gas is separated from the product. Further, the present invention encompasses any means for charging a container with compressed gas by a consumer. 
     The top of container  1  includes a valve  5 , which preferably is conventional, that is mounted in valve cup  70  and is in fluid communication with the product. Valve cup  70  is attached to cone  40  by conventional means. Cone  40  is seamed to a neck  57  of body  30 . 
       FIG. 2  shows a schematic of a charging/recharging device  110 . Device  110  includes a cup  120  and a compressed gas delivery system  140 . Cup  120  includes a base  122  and a sidewall  124  that forms a recess  126  for receiving the lower portion of can body  30 . Delivery system  140  includes a compressed gas source  142 , a communication channel  144 , and an interface  146 , preferably male, such as a needle that can engage the grommet of valve of the container. 
     Delivery system  140  encompasses any source of compressed gas, including without limitation an air pump or compressor, a canister of compressed air or other compressed gas, and the like. The compressed gas canister can be replaceable, or the delivery system or recharging device can be single-use and disposable. Optionally, device  110  may be matched to the container or container requirements, such that delivery system  140  pressurizes container  1  to a desired or predetermined pressure, which can be chosen to optimize the delivery and spray performance, and/or to minimize the material used in the container. Because the can is pressurized as described, aerosol can  1  has a maximum internal pressure that is lower than that of a conventional aerosol can, which lower pressure enables lightweighting compared with conventional aerosol cans. The predetermined pressure at which aerosol can is pressurized by compressed gas system  140  may be chosen according to both spray performance and can lightweighting according to factors that will be understood by persons familiar with aerosol can technology. For an example of means for making device  110  and can  1  work together, device  110  and container  1  can be physically designed to connect or interlock together, and male interface  146  can be physically designed to connect or interlock together with grommet  36  of the corresponding valve. The connections or interlocks, for example, can be key and keyway slots that align only when device  110  is matched with the appropriate container  1 . Alternatively, an electronic or other non-physical lock out may be used. In this way, sufficient pressure can be safely achieved without undue overfilling. 
     Preferably, a consumer engages container  1  with device  110  by inserting the can into recess  126 , according to mechanical or electronic interlocks that may be provided. Upon interface  146  engaging the grommet or vale and satisfying any interlocks and safety conditions, delivery system  140  releases gas from compressed gas source  142 . System  140  may be matched to a particular container, such that system  140  is capable of only pressurizing a container to a single predetermined and designed pressure. Alternatively, system  140  may be interlocked and controlled to recognize one or more particular containers, and in this way provide a predetermined and designed pressure that matches the particular container. Alternatively, compressed gas source can include an overpressure release valve to prevent overfilling. 
     To manufacture the package, a manufacturer can fill a product into a can on a conventional filling line at atmospheric or near atmospheric pressure and then (preferably) seal the container such that it is for pressurizing. The filled container can then be shipped with only atmospheric or near atmospheric pressure inside. The inventors believe that the above configurations and processes would reduce the cost and complexity of aerosol can filling operations, as they could resemble beverage filling operations, as well as the following advantages: 
     Embodiments of aerosol containers according to the present invention can be smaller and deliver the same amount of product, as today approximately 40% of the container volume is used for the compressed air propellant. 
     DOT and other testing requirements for cans would be substantially simplified, allowing lightweighting of containers, as non-pressurized containers or containers having near atmospheric pressure would be used in shipment. In preferred embodiments, the containers would not be subject to DOT shipping regulations, such as those pertaining to DOT-2Q and DOT-2P regulations. 
     Containers in use would be pressurized to lower pressures reducing container structural requirements as well. This is because only the pressure required for one use is needed (perhaps 3 bar vs. 7-8 bar that is sometimes used to assure adequate pressure at the point at which most of the product has already been dispensed). 
     The present invention could enable more widespread use of less expensive plastic aerosols which do not have the barrier performance to retain pressure of long time periods. In that regard, body  30  cold be formed by a conventional plastic. 
     Indoor are quality is improved because compressed gas is used in place of a conventional propellant, such as a volatile hydrocarbon compounds including propane, butane, isobutene, DME, and methyl ethyl ether.