Foam generating and dispensing device

Claim 1

In a foam producing and dispensing device for use with a deformable bottle containing foamable liquid and air, the device including cap means having an internally threaded depending skirt portion for attachment to external threads on the bottle mouth, a central upstanding conduit portion defining a discharge passage in communicating relation with the bottle and an annular surface between the discharge portion and the skirt, a mixing chamber with an inlet at its lower end in communication with a dip tube depending below the level of foamable liquid in the bottle, the mixing chamber being formed by a depending cylindrical wall portion in a sealing washer separate from the cap, air inlet passages through said cylindrical wall portion elevated above the level of liquid in the bottle, a check valve in the mixing chamber inlet and a foam homogenizing element in an outlet at the upper end of the mixing chamber and in communication with the discharge passage, the device being operative on collapsing deformation of the bottle to force the foamable liquid and air into the mixing chamber and deliver foam through the discharge passage, the improvement comprising: means defining a separate air return inlet through the cap means externally of the mixing chamber to establish direct fluid communication between the atmosphere and the bottle interior, said return air inlet defining means including a pair of continuous inner and outer rib projections extending between said sealing washer and the annular surface of the cap thereby to establish an annular space between said ribs, the cap and said sealing washer isolated from fluid communication with the mixing chamber and the discharge passage, the cap and said washer respectively having apertures formed therein in communication with said annular space; and means defining a one-way valve operative to present the discharge of fluid from the bottle interior through said apertures in the sealing washer and thus through said air return inlet and to open said air return inlet on a reduction of pressure in the bottle to less than that of the atmosphere.