Patent Publication Number: US-2007108231-A1

Title: Dispensing device for multiple constituent systems

Description:
CROSS REFERENCE To RELATED APPLICATIONS  
      This application is a non-provisional application based on U.S. Application No. 60/723,913, filed Oct. 6, 2005, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to dispensers for multi-constituent products. More particularly, the invention relates to a dispensing device that may be attached to multiple containers for accepting constituents from the containers, and dispensing a mixed product or discrete side-by-side products.  
      2. Related Art  
      It has long been known to dispense a single-component fluid product under pressure from an aerosol or pump-type container or the like. Dispenser structures are also known which are formed on, or mountable to, a single pressurized dispensing container. Known single-container dispensing assemblies commonly include vertically-actuated valve assemblies which are triggered by vertical depression thereof, as well as tilt-actuated valve assemblies which are triggered by depression at angles between vertical and horizontal, inclusive. Such dispensing assemblies may be adequate for dispensing a single-component fluid product contained in a single pressurized container. Other dispensers may be used to convert a stream of a dispensed product into a form more useable for a given application.  
      Various types of dispensers are also known which are capable of dispensing a multi-constituent product by means of the ejection and mixing of at least two different, fluid constituents from separate containers. Dispensing devices that provide for the simultaneous release of materials from two containers in response to the pressing of a release valve or actuation of a pump generally include tubes, ducts, or similar structure for conveying each of the two materials from the respective containers to a chamber at which the materials are combined, the chamber having a single outlet port or nozzle at which the material is dispensed. For example, U.S. Pat. No. 4,773,562 discloses a dispenser of the latter type, which is used for dispensing a mixed two-constituent product. In U.S. Pat. No. 4,773,562, a dispensing head is provided-with a Y-shaped groove having lateral arms for separately conveying materials dispensed from two different containers to a median arm, where the two materials are mixed and conveyed as a combined product to a single projecting spout. Much like other prior art dispensing devices, however, this structure does not allow for easy removal and replacement of the dispensing portion after use.  
      In fluid application processes requiring the use of a multi-constituent product that must be mixed immediately before application to a given object, few known devices are capable of dispensing, mixing and applying such products in a satisfactory manner. For example, in the use of multi-component hair dye products, the user or stylist is generally required to carefully perform a number of manual operations to properly mix the individual components before applying the mixture to the hair. Epoxy adhesives, exothermic shaving creams, tooth whitening formulations, and some cleaning compounds, for example spot carpet cleaners, are further exemplary applications in which multi-constituent products must be mixed immediately before use.  
      Existing systems for dispensing multi-constituent products that are mixed or combined prior to use generally involve either (a) numerous components or (b) a large mixing system which may be difficult and/or expensive to manufacture. There is a continuing need for simple devices that can be produced economically in order to satisfy the various markets for mixed and co-dispensed products.  
      There exists an unmet need for an economical and ergonomic device and/or system that effectively and simultaneously receives constituents from multiple pressurized containers and dispenses the constituents as one of a mixed product, partially mixed product, or discrete side-by-side product streams. For example, where a chemical reaction is desired after dispensing, providing separate containers having a common nozzle for mixing and dispensing may be desirable. For example, to effectively apply an adhesive to a surface, it may be desirable to simultaneously dispense the component adhesive base along with the chemical activator capable of activating the adhesive properties of the adhesive base. The adhesive base and the chemical activator may, for example, be contained in first and second pressurized containers, and may then be released and mixed to form a homogeneous mixture which is dispensed onto a surface to be bonded. Other applications of chemical products that may benefit from mixing and dispensing through a common nozzle assembly include exothermic applications, where mixing two chemicals would yield a heated dispensed chemical composition. The unsolved challenges that have prohibited successful implementation of such multi-container applications, especially in the consumer products market, include, for example, controlled and consistent dispensing of a known quantity of each chemical, ability to dispense the chemicals in other than a 1:1 ratio, high manufacturing costs, and truly homogeneous mixing prior to expelling the mixed product through the nozzle outlet.  
     BRIEF SUMMARY OF THE INVENTION  
      In one embodiment, the present invention is a dispensing device that includes a nozzle and a head. The nozzle is adapted to receive and dispense a plurality of pressurized constituents and includes an inlet portion, an outlet portion spaced from the inlet portion, and an actuation member receiving portion. The head is configured to receive the dispensing nozzle and includes a bottom part mountable atop a plurality of pressurized containers, and a top part adapted to be received on the bottom part of the head so as to substantially enclose the nozzle. The top part of the head has a resilient actuation portion formed integrally thereon and adapted to be depressed by a user, and an actuation member disposed on an internal surface of the resilient actuation portion of the head for contacting the nozzle actuation member receiving portion. When the nozzle and the head are mounted atop the plurality of pressurized containers and the resilient actuation portion of the head is depressed by the user, the nozzle shifts relative to the head so as to release the pressurized constituents from each of the plurality of pressurized containers into the nozzle for dispensing therefrom. The actuation member receiving portion of the nozzle can be a wedge-shaped recess and the actuation member disposed on an internal surface of the resilient actuation portion of the head an actuation tab adapted to be received by the wedge-shaped recess. Alternatively, the actuation member receiving portion of the nozzle can be a wedge-shaped tab and the actuation member disposed on an internal surface of the resilient actuation portion of the head an actuation recess adapted to receive the wedge-shaped tab.  
      The nozzle of the dispensing device can be adapted to shift at least partially laterally when the resilient actuation portion of the head is depressed by the user so as to activate at least one tilt-actuated valve on the plurality of pressurized containers. The nozzle can be adapted to mix the plurality of pressurized constituents and dispense the constituents as a mixed product.  
      The nozzle can also include a mixing chamber interposed between the inlet portion and the outlet portion to form a convoluted flow path between the inlet portion and the outlet portion for mixing the constituents to form the mixed product. The nozzle can have a combining portion in fluid communication with the inlet portion for receiving the constituents, and a mixing portion in fluid communication with the combining portion, where the mixing portion includes a plurality of mixing cells in fluid communication with one another along the direction of the flow path. At least a portion of the mixing portion of the nozzle can taper inwardly toward the outlet portion. The nozzle can be adapted to receive a plurality of pressurized constituents and dispense the constituents as discrete, side-by-side product streams.  
      The inlet portion of the nozzle can include a first inlet having a first channel, and a second inlet spaced from the first inlet and having a second channel. The nozzle can include a first flow chamber fluidly connecting the first channel to the outlet portion, at least a portion of the first flow chamber tapering inwardly towards the outlet portion, a second flow chamber fluidly connecting the second channel to the outlet portion, the second flow chamber being parallel to the first flow chamber and at least a portion of the second flow chamber tapering inwardly towards the outlet portion, and a wall disposed between the first flow chamber and the second flow chamber, the wall being configured, in use, to keep separate constituents from each of the plurality of pressurized containers. When the constituents from the plurality of pressurized containers are received in the first and second inlets, the constituents are conveyed through the first and second channels to the first and second flow chambers, respectively, to the outlet portion so as to be dispensed as discrete side-by-side product streams at the outlet portion.  
      An other embodiments, the invention is a nozzle for mixing a plurality of pressurized constituents and dispensing the constituents as a mixed product. The nozzle has an inlet portion for receiving the plurality of pressurized constituents and an outlet portion spaced from the inlet portion, the outlet portion for dispensing the mixed product. The nozzle also includes a mixing chamber interposed between the inlet portion and the outlet portion, the mixing chamber forming a convoluted flow path between the inlet portion and the outlet portion for mixing the constituents to form the mixed product. The mixing chamber can have a combining portion in fluid communication with the inlet portion for receiving the constituents, and a mixing portion in fluid communication with the combining portion, where the mixing portion includes a plurality of mixing cells in fluid communication with one another along the direction of the flow path, at least a portion of the mixing portion tapering inwardly toward the outlet portion. The inlet portion can include a plurality of inlets adapted to receive a valve stem on each of a plurality of pressurized containers. Each of the plurality of inlets can have interior walls having a conical configuration and can have a crab claw seal. The nozzle may be disposable. According to embodiments of the invention, the nozzle can have a channel from each of the plurality of inlets to the mixing chamber, the channels converging at a confluence in the combining portion. The confluence can be about equidistant from each inlet and each channel can have dimensions equal to the dimensions of the other channel such that, in use, the relative percentage by weight of each constituent in the mixed product is equal. Alternatively, each channel has dimensions that are different from the dimensions of the other channel such that, in use, the relative percentage by weight of each constituent in the mixed product differs from the relative percentage by weight of each other constituent in the mixed product.  
      Mixing portion of the nozzle can include a plurality of mixing portions including a first mixing portion in fluid communication with the combining portion, where the first mixing portion has a plurality of mixing cells in fluid communication with one another via consecutively unaligned openings along the direction of the flow path. The mixing portion can also have a second mixing portion in fluid communication with the first mixing portion, where the second mixing portion includes a plurality of mixing cells in fluid communication with one another via consecutively unaligned openings along the direction of the flow path. At least one of the first and second mixing portions of the mixing chamber can taper inwardly toward the outlet portion. The plurality of mixing cells of the first mixing portion can be separated by walls, each wall including at least one of the consecutively unaligned openings therein. The plurality of mixing cells of the second mixing portion are separated by walls, each wall including at least one of the consecutively unaligned openings therein. The first mixing portion can be the portion of the mixing chamber that tapers inwardly toward the outlet portion. Each of the plurality of mixing cells in the first mixing portion can become consecutively smaller than a previous mixing cell in the direction of the flow path. The second mixing portion can have a cylindrical configuration.  
      The outlet portion of the nozzle can include a cylindrical dispensing portion in fluid communication with the second mixing portion. The nozzle can include a top part and a bottom part, where the top and bottom parts are ultrasonically welded to one another. The top part and the bottom part can include walls integral therewith in the first mixing portion, the walls substantially separating the plurality of mixing cells and having at least one of the consecutively unaligned openings disposed therein. The walls of first mixing portion of the top part can substantially align with the walls of first mixing portion of the bottom part. The nozzle top part and the bottom part can include walls integral therewith in the second mixing portion, the walls substantially separating the plurality of mixing cells and having at least one of the consecutively unaligned openings disposed therein. The walls of the second mixing portion of the top part and the walls of the second mixing portion of the bottom part can alternatingly intermesh in the direction of the flow path between the inlet portion and the outlet portion.  
      In other embodiments, the invention is a dispensing system that includes a plurality of pressurized containers each having a valve stem; and a dispensing device as described above attached to the plurality of pressurized containers. The pressure in each of the plurality of pressurized containers can different from the pressure in another of the plurality of pressurized containers such that, in use, the constituents from each of the plurality of pressurized containers form a predetermined percentage by weight of a dispensed product. Alternatively, the pressure in each of the plurality of pressurized containers is equal to the pressure in another of the plurality of pressurized containers such that, in use, the constituents from each of the plurality of pressurized containers form a predetermined percentage by weight of a dispensed product. The valve on one of the plurality of pressurized containers can have dimensions that are different from the valve dimensions on another of the plurality of pressurized containers such that, in use, the constituents from each of the plurality of pressurized containers form a predetermined percentage by weight of a dispensed product. The valve of each of the plurality of pressurized containers can be a tilt-actuated valve. The dispensing system of the invention can include a collar adapted to secure the plurality of pressurized containers to one another.  
      In other embodiments, the invention is a mixing nozzle including an inlet portion adapted to accept constituents from each of a plurality of pressurized containers, an outlet portion adapted to dispense a mixed product and a mixing chamber forming a convoluted flow path between the inlet portion and the outlet portion, the mixing chamber being adapted, in use, to mix the constituents to form the mixed product. The mixing chamber can include a combining portion in fluid communication with the inlet portion, the combining portion, in use, being adapted to receive the constituents therein, a first mixing portion in fluid communication with the combining portion, the second mixing portion including a plurality of mixing cells in fluid communication with one another via consecutively unaligned openings along the direction of the flow path, and a second mixing portion in fluid communication with the first mixing portion, the second mixing portion including a plurality of mixing cells in fluid communication with one another via consecutively unaligned openings along the direction of the flow path. At least one mixing portion of the mixing chamber can taper inwardly toward the outlet portion.  
      The invention is also a multi-constituent side-by-side dispensing nozzle mountable atop a plurality of pressurized containers. The side-by-side dispensing nozzle has an inlet portion adapted to receive constituents from each of the plurality of pressurized containers. The inlet portion includes a first inlet having a first channel and a second inlet having a second channel. The nozzle also has an outlet portion adapted to dispense a product, a first flow chamber fluidly connecting the first channel to the outlet portion, at least a portion of the first flow chamber tapering inwardly towards the outlet portion, a second flow chamber fluidly connecting the second channel to the outlet portion, the second flow chamber being parallel to the first flow chamber and at least a portion of the second flow chamber tapering inwardly towards the outlet portion, and a wall disposed between the first flow chamber and the second flow chamber. The wall is configured such that, in use, it keeps separate the constituents from each of the plurality of pressurized containers. When constituents from the plurality of pressurized containers are received in the first and second inlets, the constituents are conveyed through the first and second channels to the first and second flow chambers, respectively, to the outlet portion so as to be dispensed as discrete side-by-side product streams at the outlet.  
      Further advantages, as well as the structure and function of exemplary embodiments, will become apparent from a consideration of the following description, drawings, and examples. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The foregoing and other features and advantages of the invention will be apparent from the following, more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.  
       FIG. 1  depicts an exploded front perspective view of an exemplary embodiment of a dispensing system according to the present invention;  
       FIG. 2  depicts a front view of an exemplary dispensing system according to the present invention;  
       FIG. 3  depicts a front perspective view of an exemplary embodiment of a mixing nozzle top part according to the present invention;  
       FIG. 3   a  depicts a bottom view of the exemplary mixing nozzle top part depicted in  FIG. 3  according to the present invention;  
       FIG. 3   b  depicts a sectional view of the exemplary mixing nozzle top part depicted in  FIG. 3   a  according to the present invention;  
       FIG. 4  depicts a front perspective view of an exemplary embodiment of a mixing nozzle bottom part according to the present invention;  
       FIG. 4   a  depicts a top view of the exemplary mixing nozzle bottom part depicted in  FIG. 4  according to the present invention;  
       FIG. 4   b  depicts a sectional view of the exemplary mixing nozzle bottom part depicted in  FIG. 4   a  according to the present invention;  
       FIG. 4   c  depicts a sectional view of the exemplary mixing nozzle bottom part depicted in  FIG. 4   a  according to the present invention;  
       FIG. 4   d  depicts a detail view of the inlet portion of the exemplary mixing nozzle bottom part depicted in  FIG. 4   c  according to the present invention;  
       FIG. 5  depicts a front perspective view of an exemplary embodiment of a mixing nozzle top part according to the present invention;  
       FIG. 5   a  depicts a bottom view the exemplary mixing nozzle top part depicted in  FIG. 5   a  according to the present invention;  
       FIG. 5   b  depicts a sectional view of the exemplary mixing nozzle top part depicted in  FIG. 5   a  according to the present invention;  
       FIG. 6  depicts a front perspective view of an exemplary embodiment of a mixing nozzle bottom part according to the present invention;  
       FIG. 6   a  depicts a top view of the exemplary mixing nozzle bottom part depicted in  FIG. 6  according to the present invention;  
       FIG. 7  depicts a front perspective view of an exemplary embodiment of a top part of a dispensing device head according to the present invention;  
       FIG. 7   a  depicts a top view of the exemplary top part of the dispensing device head depicted in  FIG. 7  according to the present invention;  
       FIG. 7   b  depicts a front view of the exemplary top part of the dispensing device head depicted in  FIG. 7  according to the present invention;  
       FIG. 7   c  depicts a sectional view of the exemplary top part of the dispensing device head depicted in  FIG. 7   a  according to the present invention;  
       FIG. 8  depicts a front perspective view of an exemplary embodiment of a bottom part of a dispensing device head according to the present invention;  
       FIG. 8   a  depicts a top view of the exemplary bottom part of the dispensing device head depicted in  FIG. 8  according to the present invention;  
       FIG. 9  depicts a front perspective view of an exemplary embodiment of a base collar for pressurized containers according to the present invention;  
       FIG. 10  depicts an exploded front perspective view of an exemplary side-by-side dispensing nozzle assembly according to the present invention;  
       FIG. 10   a  depicts a bottom view of an exemplary top part of the side-by-side dispensing nozzle depicted in  FIG. 10  according to the present invention;  
       FIG. 10   b  depicts a top view of an exemplary bottom part of the side-by-side dispensing nozzle depicted in  FIG. 10  according to the present invention;  
       FIG. 11  depicts an exemplary embodiment of a dispensing system operating according to the present invention;  
       FIG. 12  depicts a mixing nozzle according to an exemplary embodiment of the present invention;  
       FIG. 12  depicts a detail of the inlet columns of the mixing nozzle of  FIG. 12  according to an exemplary embodiment of the present invention;  
       FIG. 13  depicts a mixing nozzle molding configuration according to an exemplary embodiment of the present invention;  
       FIG. 14A  depicts a top view of a unitarily molded head and mixing nozzle according to an exemplary embodiment of the present invention;  
       FIG. 14B  depicts a bottom view of a unitarily molded head and mixing nozzle according to an exemplary embodiment of the present invention;  
       FIG. 14C  depicts a side view of the unitarily molded head and mixing nozzle of  FIG. 14A  in an unactuated state according to an exemplary embodiment of the present invention;  
       FIG. 14D  depicts a side view of the unitarily molded head and mixing nozzle of  FIG. 14A  in an actuated state according to an exemplary embodiment of the present invention;  
       FIG. 15  depicts a one piece head according to an exemplary embodiment of the present invention;  
       FIG. 16  depicts a top view of a device that includes a shipping post; according to an exemplary embodiment of the present invention;  
       FIG. 17  depicts an alternative embodiment of a dispensing device according to an exemplary embodiment of the present invention;  
       FIG. 17A  depicts an exploded view of the dispensing device of  FIG. 17  according to an exemplary embodiment of the present invention; and  
       FIG. 17B  depicts actuation of the dispensing device of  FIG. 17  according to an exemplary embodiment of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Embodiments of the invention are discussed in detail below. In describing embodiments, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. While specific exemplary embodiments are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention. All references cited herein are incorporated by reference as if each had been individually incorporated.  
       FIG. 1  depicts an exploded front perspective view of an exemplary embodiment of a dispensing system  10  according to the present invention. The dispensing system  10  may include a dispensing device head having a top part  11  and a bottom part  12  which may be mounted atop a plurality of pressurized containers  14   a ,  14   b . Alternatively, the dispensing device head may be formed as one piece (See  FIG. 15 ). Bottom part  12  of the dispensing device head may, for example, include appropriately sized openings  12   a ,  12   b  for receiving a top portion  15   a ,  15   b  of each of the plurality of pressurized containers  14   a ,  14   b , respectively. Additionally, a base collar  13  having receiving openings  13   a ,  13   b  may also be employed to secure the base ends of the pressurized containers  14   a ,  14   b  together. Plastic shrink-wrap, for example, may also be used to secure the pressurized containers together as a unit. Alternatively, the pressurized containers  14   a ,  14   b  may be embodied, for example, as a single container having a plurality of separated compartments therein for each pressurized constituent. Each of the plurality of pressurized containers  14   a ,  14   b  may also include a valve having a valve stem  16   a ,  16   b , respectively, for release of pressurized constituents therein. The valves  16   a ,  16   b  may, for example, be vertically-actuated valves or, alternatively, tilt-actuated valves.  
       FIG. 1  further shows the dispensing system  10  including a nozzle such as, for example, mixing nozzle  17 , which may be received within the dispensing device head and adapted to receive the valve stems  16   a ,  16   b  of the plurality of pressurized containers  14   a ,  14   b . Mixing nozzle  17  may include a top part  17   a  and a bottom part  17   b . Top part  17   a  and bottom part  17   b  of the mixing nozzle  17  may be attached to one another to form mixing nozzle  17  by any known method of forming a sealed connection including, for example, fasteners, friction fitting, adhesive, a tongue and groove joint, and/or ultrasonic welding or the like. Bottom part  17   b  of the mixing nozzle  17  may also include a front nozzle portion  18  which may receive a valve insert  19 , such as a mechanical breakup valve insert, to atomize a dispensed product such that it is dispensed in the form of a spray, including, for example, a fine spray. A nozzle of the dispensing system  10  may be adapted to vary spray properties by modifying the dimensions of the valve insert  19 , removing the valve insert  19 , and/or adjusting the pressure of the propellant in the pressurized containers  14   a ,  14   b . Top part  17   a  and bottom part  17   b  of the mixing nozzle  17  are discussed further below.  
       FIG. 2  depicts a front view of an exemplary dispensing system  10  according to the present invention. The plurality of pressurized containers  14   a ,  14   b  may be secured together by the top and bottom parts  11 ,  12  of the dispensing device head and the base collar  13  to form a hand-held, ergonomic dispensing system  10 . Similar exemplary dispensing systems are shown and described in U.S. Pat. No. 6,877,924, U.S. Pat. No. 6,168,335, U.S. Design Pat. D480,960, International Application No. PCT/US2003/022282 published as WO 2004/007346A2, and International Application No. PCT/US2004/043812 published as WO 2005/065343A2, each of which is incorporated herein by reference in its entirety.  
       FIGS. 3, 3   a  and  3   b  depict several views of an exemplary mixing nozzle top part  17   a .  FIG. 3 , for example, depicts a front perspective view of an exemplary embodiment of a mixing nozzle top part  17   a  according to the present invention. The exemplary mixing nozzle top part  17   a  includes, in series, a top combining portion  21 , a first top mixing portion  22 , a second top mixing portion  23 , and a nozzle top outlet portion  24 , each of which is shown in further detail in  FIG. 3   a . As further discussed herein, the mixing nozzle top part  17   a  may be attached to the mixing nozzle bottom part  17   b  to form mixing nozzle  17 .  
       FIG. 3   a  depicts a bottom view of the exemplary mixing nozzle top part  17   a  depicted in  FIG. 3  according to the present invention. The exemplary mixing nozzle top part  17   a  includes mixing chamber top portion  20 . The mixing chamber top portion  20  includes, in series, top combining portion  21 , first top mixing portion  22 , second top mixing portion  23 , and nozzle top outlet portion  24 . Top combining portion  21  includes, for example, top inlet feed portions  21   a ,  21   b  in fluid communication with a central confluence top portion  21   c . First top mixing portion  22  includes a plurality of mixing cells  22   a ,  22   b ,  22   c  separated from the central confluence top portion  21   c  of the top combining portion  21 , and from one another, by a plurality of walls  25  therebetween. The first mixing cell  22   a  of the first top mixing portion  22  is in fluid communication with the central confluence top portion  21   c  of the top combining portion  21  via a flow opening  26 . Likewise, each of the mixing cells  22   a ,  22   b ,  22   c  is in fluid communication with one another via flow openings  26 , which may be consecutively unaligned along a general direction of the flow path so as to induce a turbulent flow to mix constituents received therein. The first top mixing portion  22  also includes a tapered configuration, the plurality of mixing cells  22   a ,  22   b ,  22   c  having consecutively decreasing volumes, respectively, in a direction towards the nozzle top outlet portion  24 .  
      Second top mixing portion  23  includes a plurality of mixing cells  23   a ,  23   b ,  23   c  separated from the first top mixing portion  22 , and from one another, by a plurality of walls  27  therebetween. The first mixing cell  23   a  of the second top mixing portion  23  is in fluid communication with the last mixing cell  22   c  of the first top mixing portion  21  via a flow opening  26 . Likewise, each of the mixing cells  23   a ,  23   b ,  23   c  is in fluid communication with one another via flow openings  28 , which may be aligned along a general direction of the flow path toward the top outlet portion  24 . The second top mixing portion  23  may have a substantially cylindrical configuration extending in a direction towards the nozzle top outlet portion  24 . A top actuation member receiving portion  29  is also included, for example, at an end of the mixing nozzle top part  17   a  to receive an actuation member  52 , discussed further below with regard to  FIGS. 7   b  &amp;  7   c .  FIG. 3   b  depicts a sectional view of the exemplary mixing nozzle top part  17   a  depicted in  FIG. 3   a  according to the present invention.  
       FIGS. 4, 4   a  and  4   b  depict several views of an exemplary mixing nozzle bottom part  17   b .  FIG. 4 , for example, depicts a front perspective view of an exemplary embodiment of a mixing nozzle bottom part  17   b  according to the present invention. The exemplary mixing nozzle bottom part  17   b  includes, in series, a bottom combining portion  31 , a first bottom mixing portion  32 , a second bottom mixing portion  33 , and a nozzle bottom outlet portion  34  with optional front nozzle portion  18 , each of which is shown in further detail in  FIG. 4   a . The mixing nozzle bottom part  17   b  is adapted to be mated with and attached to the mixing nozzle top part  17   a  described above with reference to  FIGS. 3, 3   a  and  3   b  to form mixing nozzle  17 .  
       FIG. 4   a  depicts a top view of the exemplary mixing nozzle bottom part  17   b  depicted in  FIG. 4  according to the present invention. The exemplary mixing nozzle bottom part  17   b  includes the mixing chamber bottom portion  30 . The bottom portion of mixing chamber  20  includes, in series, bottom combining portion  31 , first bottom mixing portion  32 , second bottom mixing portion  33 , and nozzle bottom outlet portion  34 . Bottom combining portion  31  includes, for example, bottom inlet feed portions  31   a ,  31   b  in fluid communication with a central confluence bottom portion  31   c . First bottom mixing portion  32  includes a plurality of mixing cells  32   a ,  32   b ,  32   c  separated from the central confluence bottom portion  31   c  of the first bottom mixing portion  31 , and from one another, by a plurality of walls  35  therebetween. The first mixing cell  32   a  of the first bottom mixing portion  22  is in fluid communication with the central confluence bottom portion  31   c  of the bottom combining portion  31  via a flow opening  36 . Each of the mixing cells  32   a ,  32   b ,  32   c  is in fluid communication with one another via flow openings  36 , which may be consecutively unaligned along a general direction of the flow path so as to induce a turbulent flow to mix constituents received therein. The first bottom mixing portion  32  also has a tapered configuration matching the first top mixing portion  22 , the plurality of mixing cells  32   a ,  32   b ,  32   c  having consecutively decreasing volumes, respectively, in a direction towards the nozzle bottom outlet portion  34 .  
      Second bottom mixing portion  33  includes a plurality of mixing cells  33   a ,  33   b ,  33   c ,  33   d  separated from the first bottom mixing portion  32 , and from one another, by a plurality of walls  37  therebetween. The first mixing cell  33   a  of the second bottom mixing portion  33  is in fluid communication with the last mixing cell  32   c  of the first bottom mixing portion  31  via a flow opening  36 . Each of the mixing cells  33   a ,  33   b ,  33   c ,  33   d  is in fluid communication with one another via flow openings  38 , which may be aligned along a general direction of the flow path toward the bottom outlet portion  34 . The second bottom mixing portion  33  may have a substantially cylindrical configuration extending in a direction towards the nozzle bottom outlet portion  34 . Bottom part  17   b  of the mixing nozzle  17  may also include a front nozzle portion  18  which may receive a valve insert  19  such as a mechanical breakup valve insert to atomize a dispensed product such that it is dispensed in the form of a fine spray. A bottom actuation member receiving portion  39  is also included at an end of the mixing nozzle bottom part  17   b  to receive an activation member  52 , discussed further below with regard to  FIGS. 7   b  &amp;  7   c .  FIG. 4   b  depicts a sectional view of the exemplary mixing nozzle bottom part  17   b  depicted in  FIG. 4   a  according to the present invention.  
       FIG. 4   c  depicts a sectional view of the exemplary mixing nozzle bottom part  17   b  depicted in  FIG. 4   a  according to the present invention. The mixing nozzle bottom part  17   b  further includes inlet portion  40  including inlet columns  40   a ,  40   b . Inlet columns  40   a ,  40   b  include inlets  41   a ,  41   b , respectively, which may have conical configurations so as to more readily accept protruding valve stems  16   a ,  16   b  of pressurized containers  14   a ,  14   b . Inlet columns  40   a ,  40   b  further include inlet channels  42   a ,  42   b  extending therethough and fluidly connecting inlets  41   a ,  41   b  to bottom inlet feed portions  31   a ,  31   b .  FIG. 4   d  depicts a detail view of the inlet portion of the exemplary mixing nozzle bottom part  17   b  depicted in  FIG. 4   c . As shown in  FIG. 4   d , inlets  41   a ,  41   b  may also include crab claw seals  43   a ,  43   b , respectively, which can serve to grab and seal inserted valve stems  16   a ,  16   b  and thus avoid the need for o-rings or other seals and additional parts.  
      Upon assembly of mixing nozzle top part  17   a  and mixing nozzle bottom part  17   b  to form mixing nozzle  17 , top and bottom combining portions  21  and  31  align to form the mixing nozzle combining portion; first top and bottom mixing portions  22  and  32  align to form the mixing nozzle first mixing portion; second top and bottom mixing portions  23  and  33  align to form the mixing nozzle second mixing portion; and nozzle top and bottom outlet portions  24  and  34  align to form the mixing nozzle outlet portion. In the first mixing portion of the mixing nozzle  17 , top walls  25  align with bottom walls  35  to substantially separate the combined mixing cells formed by top mixing cells  22   a ,  22   b ,  22   c  and bottom mixing cells  32   a ,  32   b ,  32   c , respectively. Likewise, top flow openings  26  align with bottom flow openings  36  to create continuous flow openings between the combined mixing cells at staggered positions along the general direction of the flow path.  
      Conversely, in the second mixing portion of the mixing nozzle  17 , top walls  27  may be, upon assembly, intermeshed between bottom walls  37  such that top walls  27  bisect each of the bottom mixing cells  33   b ,  33   c ,  33   d  and bottom walls  37  bisect each of the top mixing cells  23   a ,  23   b ,  23   c . Furthermore, upon assembly of the mixing nozzle top and bottom parts  17   a ,  17   b , the top flow openings  28  may be unaligned with the bottom flow openings  38  so as to induce a turbulent flow to mix constituents received therein. The mixing portion may also have a portion thereof with a tapered configuration such that the plurality of combined mixing cells have consecutively decreasing volumes, respectively, in a direction towards the nozzle outlet portion.  
       FIGS. 5, 5   a  and  5   b  depict several views of an exemplary mixing nozzle top part  17   a . The mixing nozzle top part  17   a  shown in  FIGS. 5, 5   a  and  5   b  is substantially the same as that depicted in  FIGS. 3, 3   a  and  3   b  except for the extended configuration of the nozzle top outlet portion  24  and several additional top attachment features  44   a ,  44   b ,  45   a ,  45   b ,  46   a  and  46   b . In this embodiment, the nozzle top outlet portion  24  may have a cylindrical configuration and may be provided with top attachment features including side tabs  44   a ,  44   b  and side tab posts  45   a ,  45   b . A rear portion of the mixing nozzle top part  17   a  may further be provided with posts  46   a ,  46   b .  FIG. 5   a  depicts a bottom view the exemplary mixing nozzle top part depicted in  FIG. 5   a  according to the present invention.  FIG. 5   b  depicts a sectional view of the exemplary mixing nozzle top part  17   a  depicted in  FIG. 5   a  according to the present invention.  
       FIGS. 6 and 6   a  depict several views of an exemplary mixing nozzle bottom part  17   b .  FIG. 6  depicts a front perspective view of an alternative exemplary embodiment of a mixing nozzle bottom part according to the present invention. The mixing nozzle bottom part  17   b  shown in  FIGS. 6 and 6   a  is substantially the same as that depicted in  FIGS. 4, 4   a  and  4   b  except for the configuration of the nozzle bottom outlet portion  24  without nozzle front portion  18 . The mixing nozzle bottom part  17   b  in this embodiment may also include several additional bottom attachment features  47   a ,  47   b ,  48   a ,  48   b ,  49   a  and  49   b . In this embodiment, the nozzle bottom outlet portion  24  may have a cylindrical configuration and may be provided with top attachment features including side tabs  47   a ,  47   b  and side tab holes  48   a ,  48   b  capable of receiving side tab posts  45   a ,  45   b  on mixing nozzle top part  17   a . A rear portion of the mixing nozzle bottom part  17   b  may further be provided with holes  49   a ,  49   b  capable of receiving posts  46   a ,  46   b  on mixing nozzle top part  17   a .  FIG. 6   a  depicts a top view of the exemplary mixing nozzle bottom part  17   b  depicted in  FIG. 6  according to the present invention. Upon assembly of the top and bottom mixing nozzle parts  17   a ,  17   b , the mixing nozzle  17  may also be configured to receive a valve insert  19 , such as a mechanical breakup valve insert, to atomize a dispensed product such that it is dispensed in the form of a fine spray.  
       FIGS. 7, 7   a ,  7   b  and  7   c  depict several views of an exemplary dispensing device head top part  11 .  FIG. 7 , for example, depicts a front perspective view of an exemplary embodiment of a top part  11  of a dispensing device head according to the present invention. The top part  11  of the dispensing device head includes an integrally formed resilient actuation portion  50  which may be, for example, a flexible button which is adapted to be depressed inwardly and/or at least partially laterally by a user. The dispensing device head top part  11  also includes a front recess  51  through which a nozzle outlet portion of the mixing nozzle  17 , for example, may protrude when received therein. Resilient actuation portion  50  includes an actuation member  52  on the inner side thereof for contacting the actuation member receiving portion  29 , 39  on the mixing nozzle  17 , for example. Actuation member  52  may, for example, be a tab or protrusion configured to be received by the actuation member receiving portion  29 , 39  which may be in the form of a wedge-shaped recess, for example. Alternatively, actuation member  52  may, for example, be a wedge-shaped recess configured to be received by the actuation member receiving portion  29 , 39  which may be in the form of a tab or protrusion, for example.  
      When the actuation member  52  is depressed by a user, it flexes inwardly and effects at least a partial lateral movement of the mixing nozzle  17  so as to release pressurized constituents from the plurality of pressurized containers  14   a ,  14   b , into, through, and out of the mixing nozzle  17 . The dispensing device head top part  11  may also have a recessed connection skirt  53  for connection to the bottom part  12 , which bottom part  12  is discussed further below with reference to  FIG. 8 .  
       FIGS. 8 and 8   a  depict several views of an exemplary dispensing device head bottom part  12 .  FIG. 8 , for example, depicts a front perspective view of an exemplary embodiment of a bottom part  12  of a dispensing device head according to the present invention, including openings  12   a ,  12   b  adapted to receive top portions  15   a ,  15   b  of the plurality of pressurized containers  14   a ,  14   b . The dispensing device bottom part  12  further includes a curvilinear spout portion  60  having an outlet slot  61  through which the nozzle outlet portion of the mixing nozzle  17  may protrude when received therein.  FIG. 8   a  depicts a top view of the exemplary bottom part  12  of the dispensing device head depicted in  FIG. 8  according to the present invention.  
       FIG. 9  depicts a front perspective view of an exemplary embodiment of a base collar  13  for pressurized containers  14   a ,  14   b  according to the present invention. The base collar  13  includes openings  13   a ,  13   b  for receiving the base portions of the pressurized containers  14   a ,  14   b  so as to secure them together in a substantially parallel configuration. Plastic shrink-wrap, for example, may also be used to secure the pressurized containers together as a unit.  
       FIG. 10  depicts an exploded front perspective view of an alternative exemplary nozzle in the form of a side-by-side dispensing nozzle assembly  117 . The side-by-side dispensing nozzle assembly  117  includes top and bottom portions  117   a ,  117   b , respectively.  FIG. 10   a  depicts a bottom view of an exemplary top part  117   a  of the side-by-side dispensing nozzle  117  depicted in  FIG. 10 .  FIG. 10   b  depicts a top view of an exemplary bottom part  117   b  of the side-by-side dispensing nozzle  117  depicted in  FIG. 10 . Side-by-side dispensing nozzle top portion  117   a  includes several portions that are substantially the same as the top portion  17   a  of mixing nozzle  17  such as the inlet feed portions  21   a ,  21   b . The side-by-side dispensing nozzle top portion  117   a  further includes, however, a first top flow chamber  171   a  in fluid communication with inlet top feed portion  21   a  as well as a second top flow chamber  171   b  in fluid communication with inlet top feed portion  21   b . The first top flow chamber  171   a  and second flow chamber  171   b  may extend substantially the entire length of the side-by-side dispensing nozzle top portion  117   a  and are separated by a dividing wall  170   a  which also extends substantially the entire length of the side-by-side dispensing nozzle top portion  117   a.    
      Side-by-side dispensing nozzle bottom portion  117   b  includes several portions that may be substantially the same as the bottom portion  17   b  of mixing nozzle  17  such as the inlet portion  40  including inlet columns  40   a ,  40   b , inlets  41   a ,  41   b , inlet channels  42   a ,  42   b , and inlet feed portions  31   a ,  31   b . The side-by-side dispensing nozzle bottom portion  117   b  further includes, however, a first bottom flow chamber  172   a  in fluid communication with inlet channel  42   a  and bottom inlet feed portion  31   a  as well as a second bottom flow chamber  172   b  in fluid communication with inlet channel  42   b  and bottom inlet feed portion  31   b . The first bottom flow chamber  172   a  and second bottom flow chamber  172  may extend substantially the entire length of the side-by-side dispensing nozzle bottom portion  117   b  and are separated by a dividing wall  170   b  which also extends substantially the entire length of the side-by-side dispensing nozzle bottom portion  117   b.    
      Upon assembly of side-by-side dispensing nozzle top and bottom portions  117   a ,  117   b , the first top flow chamber  171   a  aligns with the first bottom flow chamber  172   a  to form a first flow chamber  171  and the second top flow chamber  171   b  aligns with the second bottom flow chamber  172   b  to form a second flow chamber  172 . Top dividing wall  170   a  also aligns with bottom dividing wall  170   b  so as to separate the first and second flow chambers  171 ,  172  and prevent mixing of constituents received in each of flow chambers  171 ,  172  until the constituents exit the nozzle  117 .  
      The exemplary side-by-side dispensing nozzle  117  may have an exterior that is structurally the same as, or substantially similar to, that of the mixing nozzle  17  discussed above with reference to, for example,  FIGS. 1, 3  and  4 . This allows the side-by-side dispensing nozzle  117  to be received within and used with the dispensing device head top and bottom parts  11 ,  12  as substantially described above.  
       FIG. 11  depicts an exemplary embodiment of the dispensing system  10  in operation. In operation, the dispensing system  10  may be held in a user&#39;s hand H such that the user&#39;s finger F can depress the resilient actuation portion  50 . When the resilient actuation portion  50  is depressed inwardly, a nozzle such as, for example, mixing nozzle  17  or side-by-side dispensing nozzle  117 , is shifted at least partially laterally within the dispensing device head so as to release the pressurized constituents through the tilt-actuated valves  16   a ,  16   b  of each of the pressurized containers  14   a ,  14   b . In turn, the constituents are received in the nozzle and dispensed therefrom as a product P in the form of, for example, an aerosol spray, a fluid stream, a homogeneous mixture or discrete side-by-side product streams. The dispensing system  10  may also be configured to dispense a multi-constituent product in other than a 1:1 ratio. Such a variable ratio multi-constituent product may be accomplished in several ways according to the present invention. For example, one of the channels  42   a ,  42   b  on the mixing nozzle  17  or side-by-side dispensing nozzle  117  of the dispensing system  10  may have dimensions different from the dimensions of the other channel such that, in use, the relative percentage by weight of each constituent in the mixed product or discrete side-by-side product streams is other than in a 1:1 ratio. Alternatively, one of the valves  16   a ,  16   b  on pressurized containers  14   a ,  14   b  may, for example, have internal dimensions different from the internal dimensions of the other valve  16   a ,  16   b  such that, in use, the relative percentage by weight of each constituent in the mixed product or discrete side-by-side product streams is other than in a 1:1 ratio. In another exemplary embodiment, the pressure in each of the plurality of pressurized containers  14   a ,  14   b  may be, for example, different from the pressure in the other pressurized container  14   a ,  14   b  such that, in use, the relative percentage by weight of each constituent in the mixed product or discrete side-by-side product streams is other than in a 1:1 ratio.  
       FIGS. 12-17  illustrate additional embodiments or features that may be used with the present invention. In general, these embodiments and features represent optional aspects of the design. These features are in the form of design choices, which allow for variability with respect to aesthetics or design variability, manufacturing options that may be employed to reduce costs or facilitate ease of molding, and features that may be advantageous for particular applications.  
      For example,  FIG. 12  illustrates an embodiment of the mixing nozzle having inlet columns with modified end portions. For clarity, the head portion is not illustrated in  FIG. 12 , so that only the contact between the mixing nozzle and pressurized containers is illustrated. During manufacture, the dispensing device must be assembled onto pressurized containers  14  (individually designated  14   a  and  14   b  in  FIG. 1 ) containing the aerosolized component products it is to dispense. This requires the insertion of the valve stems  16  (individually designated  16   a  and  16   b  in  FIG. 1 ) into the inlet columns  40  (individually designated  40   a  and  40   b  in  FIG. 1 ) of the mixing nozzle  17 . Such insertion is achieved by placing the inlet columns  40  of the nozzle onto the valve stems  16  and exerting a force along, or parallel to, the axis of the valve stems  16  (hereafter referred to as “vertical force”). Tilt-action aerosol valves that can be used with the invention are designed to be actuated primarily through the exertion of force diagonal to the valve stem; however, such valves can also be actuated by vertical force. The vertical force required to install the inlet columns  40  over the valve stems  16  could result in the inadvertent dispensing of the aerosol components to within the nozzle. This is to be avoided since the dispensed material could harden in place during the period of time prior to the product reaching the end user, resulting in the clogging or malfunction of the nozzle. This is particularly true in situations where the product to be dispensed is an adhesive, which could cure in the mixing nozzle, or a product having volatile components (including water) which could evaporate during manufacture or storage to leave a solid residue.  
      In order to avoid such inadvertent actuation, as shown in  FIGS. 12 and 12   a , the bottom of each inlet column  40  can be sloped upward from rear R (extremity closest to the nozzle actuation member) to front F (extremity closest to the outlet orifice). This slope can be curvilinear, as illustrated, or linear. This slope inhibits the valve stem  16  from being depressed by vertical force to the extent that would dispense product. Significant downward vertical force would result in the rear, or longest extremity of the inlet column, contacting the top of the pressurized container  14  (which can be referred to as the valve cup) before actuating the valve. At the same time, the upward slope towards the front of the mixing nozzle  17  allows the valve stem  16  to rock forward without contacting the valve cup and hence actuate freely in response to a diagonal force applied to the nozzle from the rear, the only direction from which the dispensing system is designed to actuate. In addition, the sloped design inhibits the valve stem  16  from being actuated by a diagonal force emanating from any direction other than the rear.  
      This feature can be used in conjunction with the interior design of the inlet channels illustrated in  FIG. 4   d , including the sealing and valve stem retention features (e.g., crab claw seals  43   a ,  43   b ) within, to require less vertical force for the insertion of valve stems  16  into the inlet columns  40  than that required for actuation of the aerosol valves. By way of example, the vertical force required to achieve initial actuation (depression by 0.030″) and full actuation (depression by 0.085″) of the Precision tilt-action aerosol valve (such as those supplied by Precision Valve Corporation 700 Nepperhan Avenue, Yonkers, N.Y. 10703) that can be used with the present dispensing system (supplied by Precision Valve Corporation 700 Nepperhan Avenue, Yonkers, N.Y. 10703) are reported in TABLE 1. The use of the illustrated curvilinear inlet columns can help ensure that forces adequate to affect actuation are not achieved.  
                           TABLE 1                                      COMPRESSION   FORCE REQUIRED TO ACTUATE VALVE (POUNDS)                             VALVE   DISTANCE   REPETITION                                                 CODE   (INCHES)   1   2   3   4   5   AVERAGE                                                 INITIAL ACTUATION:                                                                     1   0.030″   5.0   4.5   5.0   4.7   3.8   4.6       2   0.030″   3.7   4.0   3.5   4.2   3.7   3.8                                             AVERAGE FORCE TO ACTUATE   4.2                                         FULL ACTUATION:                                                                     1   0.085″   11.0   12.0   12.2   11.7   11.3   11.6       2   0.085″   9.5   12.0   10.5   11.7   9.8   10.7                                             AVERAGE FORCE TO ACTUATE   11.2                  
 
       FIG. 13  illustrates a manufacturing method that may be used in molding the mixing nozzle  17 . The mixing nozzle  17  can be molded in two pieces, as shown in  FIGS. 1-6  and  10  or molded as a single hinged piece in a clam-shell like configuration, as shown in  FIG. 13 . In either manufacturing option, the two halves of the mixing nozzle  17   a ,  17   b , may be joined by, for example, ultrasonically welding. Use of the clam shell configuration of  FIG. 13  can result in cost reduction during molding, and ultrasonic welding.  
       FIGS. 14A-14D  illustrate another embodiment that can facilitate manufacture of the device. This embodiment is useful in reducing the number of parts that must be molded while maintaining the same overall structure, design and advantages. According to this embodiment, the top of the mixing nozzle  17   a , is formed unitarily with the top of the head  11 .  FIGS. 14A and 14B  illustrate top and bottom views, respectively, of the resulting unit  173 . The top of the mixing nozzle  17   a  is joined with the top of the head  11  by way of frangible tabs  174 . The top of the mixing nozzle  17   a  can be joined to the rear of the top of the head  11  by a flexible tab or hinge  175 .  FIG. 14C  is a side view of the top portion of a dispensing system incorporating the unit  173  in an unactuated position, and illustrates the connection between the top part of the mixing nozzle  17   a  and the bottom part of the mixing nozzle  17   b .  FIG. 14D  is a side view of the top portion of a dispensing system incorporating the unit  173  upon actuation. In use, initial actuation of the device (as illustrated in  FIG. 14D ) by depression of the top of the mixing nozzle  17   a  results in breaking of the frangible tabs  174 . Thus, the frangible tabs  174  also serve as a tamper evident device. The flexible tab  175  can remain unbroken to prevent separation of the mixing nozzle  17  from the device.  
       FIG. 15  illustrates an embodiment of the invention in which the head  176  is constructed as a single piece rather than as top  11  and bottom 10 pieces. In this embodiment, the head  176  includes snap tabs  177  that can connect directly to a pressurized containers  14   a ,  14   b  (See  FIG. 1 .) Similar to the one piece construction of  FIG. 14 , this one piece version of the head  174  can reduce costs associated with molding, as well as the assembly of the device with the aerosolized components, and also precludes the possibility of inadvertent separation of the upper and lower portions of the head during end use.  FIG. 16  illustrates a top view of a device that includes a shipping post  178 , or plastic connector between the resilient actuation portion and the main body to both protect from accidental actuation during shipment and provide evidence of prior actuation or tampering. Either the two piece construction of  FIGS. 1 and 7 - 8  and one piece construction of  FIG. 15  can incorporate one or more shipping posts  178 .  
       FIG. 17  illustrates another embodiment of a dispensing device  179 . As illustrated in the exploded view of  FIG. 17A , this embodiment includes a collar piece  180  which attaches atop the pressurized containers  14   a ,  14   b . The collar  180  includes receptacles  181  that provide a pivot point for the mixing nozzle assembly  182 . The mixing nozzle  182  can be molded in a top piece  182   a  and a bottom piece  182   b . The internal configuration of the mixing nozzle  182  can be of various configurations, for example those illustrated in  FIGS. 3-6  and  10 . The top piece  182   a  and bottom piece  182   b  can also be molded in a single piece connected by a hinge similar to that illustrated in  FIG. 13 . The embodiment illustrated in  FIG. 17  includes pivot tabs  183 . The device  179  is assembled by joining the top piece  182   a  of the mixing nozzle and bottom piece  182   b  of the mixing nozzle, for example by ultrasonic welding. The pivot tabs  183  are inserted into the receptacles  181 . As illustrated in  FIG. 17B , exertion of a force on the mixing nozzle assembly  182  results in a pivoting of the mixing nozzle assembly  182  on the collar  180 , resulting in actuation of the tilt-actuated valve stems  16  of the pressurized containers  14 . Among other benefits of this embodiment is cost reduction during molding and ultrasonic welding.  
      The present invention offers several additional advantages over the prior art. The actuation system, e.g., the combination of actuation member  52  and actuation member receiving portion  29 ,  39 , provides a system where the movement of the nozzle such as, for example, mixing nozzle  17 , can be facilitated by contact at a single point. The mixing nozzle  17  can move due to a force applied to a single point of contact, for example, in the form of a wedge-shaped recess  29 ,  39  on the mixing nozzle  17 . In use, pressure applied to the resilient actuation portion  50  of the dispensing device head top portion  11 , in which the mixing nozzle  17  is encased, is transferred to the mixing nozzle  17  by the actuation member  52  which can be, for example, a triangular projection that fits into the actuation member receiving portion  29 ,  39 . This single point of contact actuation method provides the system with an additional means to equalize or accommodate manufacturing inconsistencies in pressurized containers  14   a ,  14   b  such as, for example, uneven valve stem heights, so as to provide dispensing consistency among different sets of pressurized containers.  
      Another advantage over the prior art is in the flexibility of the design. There are several different nozzle designs, as described above, that can be used interchangeably with the dispensing device of the present invention. For example, a mixing nozzle  17  such as depicted in  FIGS. 3-5  can be used to dispense a mixed product in the form of a mixed stream, as depicted in  FIG. 11 . The mixed stream can be in the form of, for example, a liquid, gel, or paste. With the insertion of a valve insert  19 , such as a mechanical breakup valve, in the mixing nozzle, this same system can be used to dispense a mixed and atomized product in the form of a fine spray. As another alternative, the nozzle can be exchanged with another nozzle, for example the side-by-side dispensing nozzle depicted in  FIG. 10 , to dispense substantially unmixed and discrete side-by-side product streams. The present invention can thus be used for a number of applications that may have previously required several differently designed devices.  
      The system as described herein is relatively inexpensive to manufacture. In the past different devices were required to provide spray, stream, side-by-side output or output having a different dispensing ratio. Because of the flexibility of the instant invention, a manufacturer can avoid additional start up costs typically involved with supplying a variety of different users with devices having different purposes to fit the individual&#39;s needs. With the instant invention, a manufacturer can meet the needs of many different users by supplying the identical dispensing device head top part  11 , dispensing device head bottom part  12 , and base collar  13 , along with a nozzle suitable to the needs of the particular user. Furthermore, the external configuration of the various nozzles is substantially identical; the only differences being in the internal structure. Accordingly, a manufacturer can use the identical set of outside molds in a variety of applications for different customers. These advantages save change-over costs and can provide space savings by using identical equipment to manufacture devices for different types of users.  
      The flexibility of the system can also provide cost savings to users. If users have different needs for different products, the user only needs to place a different type of nozzle in the device. Furthermore, if a given nozzle becomes clogged or otherwise inoperable, the inoperable nozzle can be removed and replaced; there is no need to replace the entire system. This can be especially true for users that have repeated need for a dispensing device.  
      The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. All examples presented are representative and non-limiting. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims and their equivalents, the invention may be practiced otherwise than as specifically described.