Abstract:
A foam dispenser utilizes a deformable reservoir, a foamable fluid and air or other gas; a discharge device and an arrangement for producing foam that includes a plurality of mesh screens. When the dispenser is operated, air from inside the dispenser is mixed with the fluid to produce foam. The dispenser employs a shaped and resilient deformable seal for use in quickly recharging the container with air used in the creation of foam. The dispenser also advantageously employs an integrally molded swirl manifold to create a foam of excellent quality and consistency.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a foam-producing device. 
     2. The Related Art 
     Certain known types of foam producing devices are disclosed in U.S. Pat. No. 4,147,306 and U.S. Pat. No. 4,156,505 both issued to Bennett. These employ a deformable reservoir of foamable fluid and air, a discharge device and a foam producing device which include both a foam overlay or filter and a ball check valve. The foam-producing device has a well with air passages, which form a mixing chamber. When the reservoir is squeezed, the liquid and air are mixed in the chamber. The mixture is passed through the overlay to produce foam which is discharged through the orifice. The check valve is disposed in the path of liquid flow and is opened by the squeezing action and is closed when the pressure is released. The valve, when closed, prevents downward flow of liquid or foam which otherwise could clog or jam the dispenser. However, such arrangements suffer from certain other disadvantages. 
     For example, prior art devices have multiple parts which are costly to manufacture in quantity. Moreover, many of the prior art devices require a long time to recharge air that has been discharged from the container when foam has been produced. Accordingly, one aspect of the present invention is to provide a foam nozzle and dispenser at least as efficient as earlier devices, yet manufactured with fewer parts thereby saving some assembly cost and reducing complexity. Another aspect of the present invention is to provide a foam dispenser which rapidly recharges air between discharges of foam. 
     SUMMARY OF THE INVENTION 
     In the present invention, the disadvantages of prior foam nozzles and dispensers have been found to be overcome by using a shaped resilient seal which allows the container to recharge with air in a much more efficient manner. A swirl manifold is also advantageously employed to create good quality foam and, in a preferred arrangement, is cast as an integral component in the foam-generation housing of the instant invention. The inventive foam dispenser uses fewer parts and can be more easily assembled and, therefore, can be produced and sold at a much lower cost. 
     In one aspect of the invention, a nozzle for dispensing foam is provided including a foam generation housing; a mixing conduit with an outlet and an inlet disposed in the foam generation housing for blending fluid and vapor to generate foam, a plurality of spaced apart mesh screens for creating turbulence zones disposed in the mixing conduit adjacent to the outlet; and a swirl manifold fluidly communicating with the inlet and disposed downstream from the plurality of spaced apart mesh screens for contacting the fluid with vapor to create a swirling fluid and vapor flow pattern. The swirl manifold has a surface, and defines an aperture communicating with the mixing conduit inlet and the fluid conduit outlet. The manifold surface also has at least one swirl conduit in communication with the aperture and the vapor conduit outlet; wherein the vapor flows through the swirl conduit and enters the aperture tangentially. 
     The inventive nozzle preferably includes a fluid conduit and a vapor conduit each having an outlet and an inlet; and a vent; each disposed in the foam generation housing. The plurality of screens preferably includes a first screen, and a second screen disposed downstream from the first screen. Preferably, the nozzle also includes a foam conduit housing containing a foam conduit for transporting foam created in the mixing conduit, which communicates with the mixing conduit outlet; and an adapter fixedly connected to the foam conduit housing. Preferably the adapter is slidably coupled to an outer surface of the foam generation housing for movement between an open and a closed position, the open position allowing communication between the atmosphere and the fluid and vapor in a container and the closed position preventing communication between the atmosphere and the fluid and vapor in the container. 
     Preferably the inventive nozzle&#39;s foam conduit housing has a sealing projection and at least one detent positioned to engage the outer surface of the foam generation housing when the foam conduit housing is moved between the closed and the open position. Preferably the inventive nozzle further includes a check valve disposed in the mixing conduit for preventing the back flow of fluid and foam into the container. 
     Advantageously, the inventive nozzle has its swirl manifold integrally formed with the foam generation housing, and the manifold has a central aperture and the manifold surface has a plurality of etched swirl conduits tangentially communicating with the aperture, each of the swirl conduits having a major axis. Preferably the number of swirl conduits etched in the swirl manifold surface is in the range of 2 to about 50. More preferably the number of swirl conduits are at least two and the major axis of at least one swirl conduit is disposed at right angles to a major axis of a second swirl conduit. 
     In another aspect of the invention is a nozzle for dispensing foam, including a foam generation housing having a vent; a mixing conduit disposed in the foam generation housing for blending fluid and vapor to generate foam, the mixing conduit having an outlet and an inlet; a plurality of spaced apart mesh screens for creating turbulence zones disposed in the mixing conduit adjacent to the outlet; and a flared deformable vent seal for allowing the ingress of air into the container via the vent, the seal being disposed and movably engaged within the foam generation housing for movement between an open position allowing air ingress and a closed position when foam is discharged. In the context of the present invention, the flared character of the deformable vent seal is defined by the seal meeting a cylinder outer wall at an angle of less than 75 degrees in contrast to a flat seal which would meet the outer wall at an angle near 90 degrees. 
     Preferably the inventive nozzle&#39;s vent seal has a top wide end, a radially projecting flange connected to the wide end, and a narrow bottom end defining a seal aperture. The flange is in sealing engagement with a lower surface of the foam generation housing, and the seal bottom end is in sealing engagement with the cylinder outer wall of the foam generation housing. 
     Preferably the vent seal engages the cylinder outer wall at an angle defined by the seal and the cylinder outer wall in the range of about 35 to about 55 degrees, whereby negative pressure in the container causes the seal to move away from the outer wall allowing the egress air in the container. More preferably, the vent seal is conical in shape. 
     Advantageously, the inventive nozzle has an annular resiliently deformable ring concentrically disposed outside the mixing conduit and adapted to engage the vent seal and configured for movement between an open position and a closed position similar to a crab&#39;s claw. The open position for engaging at least a portion of the first resilently deformable seal, and the closed position for pressing the vent seal to the lower surface of the foam generation housing. More preferably, the annular resiliently deformable seal is integrally cast within the foam generation housing adjacent to the lower surface to reduce production costs. 
     In another aspect of the invention, the inventive nozzle is combined with a container to provide a foam dispenser. The container is coupled to the foam generation housing by the neck. The container will typically have threads, dimples, or the like to engage the nozzle. The nozzle will have complementary threads, depressions, or the like molded on an outer surface so as to engage the container and the annular resiliently deformable seal will then move to the closed position when the foam generation housing sealingly engages the container. Preferably the container threadably engages the foam generation housing. 
     In this aspect of the present invention, foam is dispensed by increasing the pressure in the container by any suitable means. Preferably the container is composed of a flexible polymeric material and the foam is dispensed by increasing the pressure in the container by deforming the container such as by squeezing by hand, using a bellows or pump device or source of pressurized gas, and the like. Preferably an external pumping device such as trigger pump commonly found in a trigger sprayer is not used. Such an external pumping device does not increase the pressure in the container. An example of such a trigger sprayer is described in U.S. Pat. No. 6,116,472 issued to Wanbaugh, et al. on Sep. 12, 2000. 
     In operation, the foam generation housing is secured to the open neck of a container of fluid, the fluid conduit inlet is extended into the container to a depth below the fluid level, and the vapor conduit inlet is extended into the vapor space of the container. When the nozzle in the open position and the container is squeezed or pressurized, the vent seal is forced closed sealing the vent. Vapor or air flows upwardly through the vapor conduit and the fluid flows upwardly through the fluid conduit. The fluid and air are mixed together in the swirl manifold disposed in the mixing conduit creating a vortex of fluid entrained with air. The fluid/air mixture passes through the check valve and the plurality of screens and is converted to foam. The foam flows through the foam conduit section of the nozzle and is discharged. 
     When the pressure is released, the vent seal opens and air is fed through the vent hole and passed the vent seal into the container to replace the air previously used to produce foam. After the pressure is equalized, the nozzle may be placed in the closed position. The dispenser is sealed and fluid cannot leak out even if the dispenser is tilted or inverted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing features, advantages, and objects of this invention are now described in more detail with reference to the drawings in which: 
     FIG. 1 is an exploded view of a preferred embodiment of the invention; 
     FIG. 2 is a cross sectional view of the embodiment of FIG. 1 in assembled form with the nozzle in down position; 
     FIG. 3 is a view similar to FIG. 2 but with the nozzle shown in up position prior to application of squeezing pressure; 
     FIG. 4 is a view similar to FIG. 3 with the nozzle shown in up position immediately after application of squeezing pressure; 
     FIG. 5 is a bottom planar view of the swirl manifold taken along line  2 — 2  in FIG. 3; 
     FIG. 5A is a bottom planar view of the swirl manifold taken along line  5 A— 5 A in FIG. 4; 
     FIGS. 6A and 6B are detailed exploded cross sectional views of FIG. 2 showing the foam conduit holder and adapter in FIG. 6B being received onto the foam generation housing shown in FIG. 6A; 
     FIGS. 7A and 7B are detailed partial vertical cross sectional views of a preferred embodiment of the annular resilient or crab-claw ring receiving the flange of the vent seal shown in FIGS. 8,  9 A, and  9 B; 
     FIG. 8 is an operational partial cross sectional view of a preferred embodiment of the vent seal allowing the ingress of outside air into the container immediately after application of squeezing pressure; 
     FIG. 9A is a vertical cross sectional view of the vent seal shown in FIG. 8; and 
     FIG. 9B is a top planar view of the vent seal shown in FIGS.  8  and  9 A. 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIGS. 1-9, a squeezable plastic container  10  contains foamable fluid  11  and air space  13 . A plastic foam generation housing  12  is screwed on the open threaded neck  14  of container  10 . A fluid conduit  16  extends downwardly from the housing  12  into the container to a point below the level of the fluid. A check valve  18 , check valve ball  20 , first screen  22 , and second screen  24 , are disposed in the housing  12 . A foam conduit housing or plastic cap nozzle  26  is slidably connected to the housing  12 . 
     Housing  12  is provided with a first vertical hollow cylinder  28  that has an open lower end  30  and a closed upper end  32 . Cylinder  28  has an internal thread  29  and is adapted to engage an open neck  14  of container  10 . The upper end of cylinder  28  has a centrally disposed mixing conduit  34 , and a vent  36  located outside of and spaced from the mixing conduit  34 . 
     The mixing conduit  34  extends above the upper end of cylinder  28 . The mixing conduit  34  has an upper section  38  which communicates with a lower section  40  at the closed upper end  32  of the first cylinder  28 . Upper section  38  contains the first screen  22  and second screen  24 ; Lower section  40  is adapted to receive check valve  18  with check valve ball  20  slidably disposed between point stops  42  and valve seat  44 . The ball  20  normally engages the valve seat  44 . Foam and air can flow through the check valve  18  when the ball  20  engages the point stops  42 . Foam and air cannot flow through the check valve when the ball  20  engages the valve seat  44 . 
     Situated downstream from the lower section  40  and in communication therewith is aperture  46 . Downstream from aperture  46 , vapor conduit  54  is adapted to receive fluid conduit  16  spaced apart from lower section wall  50  while fluid conduit  16  comes into pressing engagement with spacers  52  molded onto lower section wall  50 . Vapor conduit  54  is annularly disposed around fluid conduit  16  and lower section wall  50  and communicates at its inlet  56  with the air space  13  in container  10 . 
     Swirl manifold  58  is disposed in lower section  40 . Swirl manifold  58  has a centrally disposed aperture  46  and a plurality of etched manifold swirl channels  60  etched into manifold surface  62  parallel with lines  5 — 5  and  5 A— 5 A and each conduit  60  extending along major axis  61 . Vapor conduit  54  communicates with aperture  46  via manifold swirl channels  60 . 
     A second hollow cylinder  64  has an open upper end  66  and is secured at its lower end  68  to the upper end  32  of the first cylinder  28 . The second cylinder  64  is disposed concentrically outside upper section  38  of the mixing conduit  34  and spaced therefrom by an annular recess  70 , the vent  36  being disposed in communication with the annular recess  70 . 
     Now referring to FIGS. 6A and 6B, the cap nozzle  26  has a horizontal discharge conduit section  74 , a vertical hollow cylindrical section  76 , and an adapter  86 . The horizontal section has an outer discharge orifice  78  and an inner intake end  80 . The vertical section  76  has an upper end which is connected to the intake end  80  and has a lower open mouth  82 . The adapter  86  is slidably coupled to the upper outer surface  88  of the mixing conduit  34  for movement between an open position (FIG. 3) and a closed position (FIG.  2 ). The adaptor  86  has sealing ring  89  which engages detent go on upper outer surface  88  in the open position and engages detent  92  on lower outer surface  88  in the closed position. Adaptor  86  also has locking ring  91  which also engages lower end  30  of housing  12  when the foam nozzle is in the closed position. 
     The upper section  38  of the mixing conduit  34  extends into the vertical cylindrical section  76  in the closed position. In the closed or down position, the vertical section wall  77  extends into annular region  70  and closes the mixing conduit  34  via plug  84  and adaptor  86  closes the vent  36 . In the open or up position, the vent  36  is exposed to ambient air which can pass into the interior of the first cylinder  28  and mixing conduit  34  is exposed to ambient air via horizontal conduit  74  and vertical section  76  to allow foam to be dispensed. 
     Now referring to FIGS. 7,  9 A and  9 B, the cone shaped vent seal  100  is disposed in the first cylinder  28 . Seal  100  has flange  102  adjacent to the lower surface  104  of the closed upper end  32  of first cylinder  28  and its narrow bottom end  106  concentrically arranged outside of and adjacent to the cylindrical outer wall  108  of lower section  40 . Flange  102  is engaged by annular or crab claw resilient seal  110  formed onto lower surface  104 . Seal  110  presses flange  102  against the lower surface  104  when the housing  12  is threaded onto the neck  14  of the container  10  and tightened. 
     In use, the first cylinder  28  is secured to the open neck  14  of the container  10  and the fluid conduit  16  is placed in position to extend into the container to a depth below the fluid  11  level while the vapor conduit  54  is allowed to extend into the air space  13  of the container  10 . When the nozzle  26  is in the up position and the container  10  is squeezed, the first annular seal  100  is forced closed. Air flows through the vapor conduit  52  and vapor swirl channel  60  and the fluid flows upwardly through the fluid conduit  16 . The fluid  11  and air  13  are mixed together in the aperture  46  of the swirl manifold  58  and the swirling fluid-air mixture passes through the first  22  and second screens  24  and is converted to foam  120 . The foam  120  flows through the vertical  76  and horizontal  74  section of the nozzle  26  and is discharged. 
     Simultaneously, the first annular resilient seal  100  prevents air  13  in the container  10  from escaping through the vent hole  36  due to the air pressure generated from squeezing the container  10  forcing the narrow bottom end  106  of seal  100  to sealingly press against outer wall  108 . 
     After the desired amount of foam  120  is discharged and the squeezing pressure on the container  10  is relieved, outside air rapidly flows into container  10  to equalize the pressure therein through annular recess  70  and vent  36  passing between the vent seal  100  and outer wall  108  at the bottom end  106  of seal  100  and into the air space  13  of container  10  (see FIG.  8 ). 
     Vapor or air is aspirated into the swirl manifold of this invention where it mixes with the fluid. Pressure fluctuations in the vortex created in the swirl manifold are believed to affect the rate of air dissolution into the fluid and the amount of foaming is at least partially determined by the strength of vortex created in the manifold. The strength of the vortex is dependent on the pressure which the container is squeezed with, the design and location of the mesh screens, and the physical characteristics of the fluid being dispensed. 
     The ratio of fluid to air is also determinative of foaming quantity and quality. Time of exposure of air and fluid also affects the rate of air dissolution and therefore the amount of foaming. The time of exposure may be controlled by dimensioning the length of the mixing conduit. Factors affecting the selection of suitable dimensions are the amount of available aspirated air and the physical characteristics of the liquid, e.g. surface tension and viscosity. The quantity of available air depends on the volume of air in the container, how vigorously the foamer container is squeezed and the dimensions of the vapor conduit. These dimensions are again often empirically determined. A suitably dimensioned foamer in the preferred embodiment described herein has been found to have a container in the range of about 50 to about 250 mls, in volume, and a mixing conduit in the range of about 25 mm to about 150 mm in overall length. The length of the upper section of the mixing conduit can be in the range of approximately 25 mm to about 50 mm in length and about 6.2 to about 13.0 mm in radius. The length of the lower section of the mixing conduit can be in the range of about 9.5 to about 13.0 mm, and have a radius of about 3.1 to about 9.5 mm. The annular vapor conduit concentrically disposed around the fluid conduit has an inner radius of about 3.0 to about 7.4 mm, an outer radius of about 3.8 to about 7.6 mm, and a length of about 10.0 to about 15.3 mm. The cylindrical fluid conduit is about 25 to about 250 mm in length and about 4.0 to about 9.5 mm in radius. The swirl manifold surface has a diameter of about 6.2 to about 13.0 mm, and an aperture diameter of about 1.6 to about 6.2 mm. Preferably four rectangular swirl channels are etched in the surface of the swirl manifold and are orthogonal to each adjacent channel&#39;s linear axis. The dimensions of each swirl channel are typically about 3.1 to about 6.2 mm in length, about 0.3 to about 0.8 mm in depth, and about 0.3 to about 1.2 mm in width. 
     The inventive foamer has a plurality of mesh screens which reduces the amount of airborne droplets into the atmosphere while creating an acceptable quality foam which does not dribble when applied to the skin, and which has an acceptable hang time on the skin. The inventive foamer preferably has a pair of mesh screens each of a size of about 2 to about 5 openings per linear millimeter, the screens being spaced apart in at least one direction at a distance of about 6 to about 8 mm to establish a pair of turbulence zones as the flow direction of the spray particles is deflected when passing through the first screen and as the flow direction of the spray particles is further deflected when passing through the second screen. 
     The container body is preferably made of such material that enables the vessel to be squeezed by hand and rapidly restored to its original form upon recovery. Examples of suitable materials include thermoplastic resins such as polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, nylon, or laminates thereof, and the like. Transparent or opaque materials may be employed, but transparent or semi-transparent, colored or colorless materials are preferred to allow a check of the level of the contents in the container. As to materials for constituting the nozzle, thermoplastic resins such as polypropylene and polyethylene are preferably used, since tight engagement must be established between the nozzle and the container. The vent seal is preferably made of an elastomer material, but any other type of resilient material such as rubber, soft plastic, or other soft resilient seal material may be used. Preferably the material has a Shore or Durometer A scale hardness of less than about 100. 
     While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the present invention.