Plug And Cavity Mechanical Break-up Button

Abstract

An aerosol valve actuator button having a swirl chamber for mechanical breakup of the product stream proximate the spray discharge orifice is constructed in two pieces, an exterior body piece including a central cavity having wall portions including a depression forming the swirl chamber surrounding a discharge orifice, and an interior insert or plug adapted to be received in the cavity of the body piece, the insert piece including a valve stem receiving socket and product flow channels.

Description

This invention relates to valve actuator spray buttons for pressurized aerosol dispensers. More particularly, this invention relates to buttons having means to mechanically break-up or nebulize the product stream into a spray of droplets.

Aerosol materials comprise an active ingredient or product and a propellant medium. In many such materials, the product and the propellant are mutually soluble such that dissolved liquid propellant is present in the emerging stream. This dissolved propellant of such a soluble system rapidly evolves as vapor from the stream upon exposure of the stream to the comparatively low pressure of the atmosphere. The rapid evolution of vapor from the product causes the stream to disintegrate into a spray of fine droplets. For such soluble systems a simple orifice will produce adequate sprays. In other aerosol materials, the product and propellant components are not mutually soluble. In such insoluble systems the product stream contains little or no propellant in a liquid state. There is no evolution of vapor from the product stream. Spray droplets must be formed by mechanical nebulization means in the flow path proximate the nozzle. Similar spray dispersion problems arise in insoluble systems in which the product is a suspension of solid, 128 or liquid particles. The present invention is concerned with improvements in such mechanical break-up means.

U.S. Pat. No. 3,083,917 issued Apr. 2, 1963, to Abplanalp et al. This patent describes actuator spray buttons having an internally molded swirl generating chamber formed as a depression on the interior of a cavity in the button body which cavity is sized to tightly engage a conventional aerosol valve stem. When the valve stem is in place in this cavity of valve stem receiving socket, the valve stem cooperates with the depressions molded in the interior of the cavity to form a complete swirl chamber and flow passages. No indexing of the button with respect to the stem is required because the swirl generating means are molded concentric with the discharge orifice.

Because the dimensions of the valve stem receiving socket are necessarily dictated by the diameter of a conventional aerosol valve stem, the cavity is quite small. It is difficult to arrange a molding die to mold the swirl chamber depression with great accuracy or detail. The mechanisms for retraction of portions of the die become too small for economical manufacture or reliability. The swirl chamber of Abplanalp et al. is thus necessarily geometrically simple as are the passages leading to it.

It is desirable to mold a plurality of accurately shaped and positioned baffles to define tangential passages which terminate in the swirl chamber to enhance the development of the needed swirling rotation of the product. Further, it is desirable to form within the passages leading from the valve stem means to initiate the break-up of the product stream prior to its introduction to the tangential passages leading to the swirl chamber.

The present invention is an improvement over the mechanical break-up button taught by the foregoing Abplanalp et al. patent in that the present invention provides adequate space to permit the molding of minute accurate swirl inducing means such as baffles and permits the formation of expansion chambers, flow accelerating restrictions, division of flow paths, and rapid changes of flow direction within the passages prior to the swirl chamber so as to improve the disintegration of the product stream into uniformly small droplets. These improvements are attained in an actuator button of conventional external size. Greater molding complexity and accuracy are permitted by forming the button of the present invention in two pieces thereby providing a cavity in the body member of greater diameter than a conventional valve stem and an insert member or plug which occupies the body cavity. This large cavity permits the use of larger and more complex die parts. The two pieces also provide a plurality of surfaces upon which complex channels, chambers and the like can be molded.

IN THE DRAWINGS

FIG. 1 is an elevational view in section of the spray actuator of the present invention in place on the valve stem of an aerosol pressurized dispenser;

FIG. 2 is a sectional view taken in the plane 2--2 of FIG. 1;

FIG. 3 is a top view of the insert member;

FIG. 4 is an elevational view in section taken in the plane 4--4 of FIG. 3;

FIG. 5 is an elevational view in section of the body member taken in the plane 5--5 of FIG. 6, and

FIG. 6 is a bottom view of the body member of FIG. 5.

Referring now to the drawings, FIGS. 1 and 2 show the spray actuator button in place on the upstanding valve stem 30 of a conventional pressurized aerosol dispenser container. The button is formed in two pieces, a body member 10 and an insert member or plug 20. The insert member 20 is assembled into the body member 10 and retained therein by friction. The body member 10 and the insert member 20 are each provided with grooves and depressions which cooperate upon assembly to form various product flow passages and a swirl generator 14 for imparting swirling motion to the product as it is dispensed to cause the product stream to nebulize or break-up into small droplets which emerge from a discharge orifice 12 extending through the exterior side wall of the body member 10.

FIGS. 3 and 4 show the insert member 20. It is provided with a central cavity 22 which constitutes a valve stem receiving socket sized to receive and firmly retain a valve stem. A chamfer 21 aids in insertion of the valve stem. Longitudinal ribs 24 are provided in the upper portion of the cavity. These ribs form stops to limit the extent to which the valve stem 30 can be inserted into cavity 22. When the valve stem is in place in the cavity as is shown in FIGS. 1 and 2, the upper portion of the cavity remains unoccupied to constitute an expansion chamber 23. An aperture 25, coaxial with bore 22 provides a path to the upper exterior of the insert member 20 for product which has emerged from bore 31 of valve stem 30 and has travelled through chamber 23.

The upper surface of the insert member 20 is provided with radial grooves 26 and a peripheral annular rabbet 27 which together form a sequence of product flow channels leading from aperture 25 to the upper peripheral edge of the insert member. These channels 26 and 27 are separated by pie-shaped post members 28. The channels become distinct passages when they are completed by assembly of the insert member 20 into the body member 10 as can be seen in FIGS. 1 and 2.

FIGS. 5 and 6 show the body member 10. The body member is provided with a cavity 11 adapted to tightly receive the insert member 20. A chamfer 13 is provided at the lower lip of the cavity 11 to aid in insertion of the insert member 20 into the body member cavity. The cavity 11 is in the form of a cylinder surmounted by a frustum of a cone. The exterior shape of the insert 20 is complementary to cavity 11. The conical surface portion 11a of the cavity 11 is provided with a shallow swirl generator depression 14 which is coaxial with the discharge orifice 12. A plurality of baffles 15 are formed within depression 14 surrounding the discharge orifice 12 thereby defining a plurality of tangential channels 15a between baffles 15 which lead from the periphery of the swirl generator 14 to the swirl chamber 12a concentric with the discharge orifice 12. Product flowing from these channels 15 to the swirl chamber 12a has imparted to it a swirling or rotational motion which persists as the product exits from the discharge orifice. The conical portion 20a of the exterior surface of insert member 20 cooperates with swirl generator depression 14 to complete the swirl generating means.

A diametrically disposed groove 16 is formed in the upper end wall of the cavity 11 of the body member 10 and has a continuation portion 17 which extends longitudinally of the side wall 11a of the cavity 11 to intercept swirl generator depression 14. Groove 16 serves as a product flow passage leading from radial passages 26 and annular passage 27 formed on the end of the insert member 20 to complete a conduit for product from the valve stem passage 31 to the swirl generator 14 and discharge orifice 12.

No particular angular indexing alignment of the insert member 20 with respect to body member 10 is required because the product passage groove 16 is formed along a diameter of the body member which diameter necessarily intercepts the central product flow aperture 25 of the insert member 20. Further, groove 16 and longitudinal portion 17 communicate with the annular product passage 27 formed by the rabbeted edge of the top of the insert irrespective of any indexing alignment of the insert and body members. Similarly, molding the swirl generator on the interior of the body cavity 11 rather than on the exterior of the insert member 20 necessarily results in concentricity with the discharge orifice thereby obviating the need for indexing. This lack of necessity for indexing is desirable from the standpoint of assembly of the insert and body members.

There exist dual paths between the product passage 16 and the supply of product. The first is direct communication of the diametrically disposed portion of product passage or groove 16 and product flow aperture 25. The second path is from aperture 25 through passages 26 and 27 to the longitudinal portion of product passage or groove 16. These redundant paths for product help insure against failure due to blockage of a passage by solidified product.

Cavity 11 in body member 10 is of relatively large dimensions permitting adequate room within the cavity forming die member of an injection mold for the retractable die pin which forms the swirl generator complex of passages and baffles on the side of cavity 11. Because of the relatively great room available for the retractable swirl generator die mechanism, an accurately formed geometrically complex swirl generator can be molded.

In operation, the spray actuator button of the present invention is manually depressed or tilted as dictated by the dispenser mounted valve. Product under the pressure exerted by the propellant in the container passes through the dispenser valve and appears in the passage 31 of valve stem initial product break-up means.

As the product continues its travel toward atmospheric pressure at the discharge orifice 12 it next encounters the restricted area of insert member aperture 25. Product in expansion chamber 23 has relatively low velocity because of the relatively large volume of chamber 23. As product exits from the chamber 23 it is suddenly accelerated through aperture 25 such that it emerges from the aperture 25 moving with relatively high velocity in a direction axial of the valve stem. The rapid acceleration further promotes division of the product into droplets. The rapidly axially moving product stream is then diverted radially to traverse the four radial passages 26 on the insert member 20. A portion of the product continues axially to passage 16 in the body member 10. That product is diverted radially.

Thus, the product is physically separated into five streams. The four streams of radial passages 26 re-combine in annular passage 27 through which the product travels circumferentially to then combine in longitudinal passage portion 17 with that portion which has traversed passage 16 in the body member 10. The foregoing directional changes, separation and recombination of the product further cause division of the product into droplets. Thus, aperture 25 and passages 26 and 16 constitute a secondary product break-up means.

The recombined product in passage portion 17 is again accelerated to high velocity by virtue of the relatively small area of passage 17. The product enters swirl generator 14 at high velocity to again expand. The product traverses the tangential passages 15a between the baffle members 15 whereby rotational motion is imparted to the product just prior to its emergence from the discharge orifice 12. This swirling rotational motion causes the product to be ejected from the discharge orifice as a spinning stream which, upon emergence, is free to centrifugally radiate into a cone of spray droplets. Thus, the swirl generator 14 constitutes a final break-up means.

Claims

I claim:

1. An aerosol valve actuator spray button comprising a body member having an axial cavity open at the bottom and an insert member occupying said cavity,

the insert member having an axial bore open at the bottom and having a lower portion adapted to snugly receive the upstanding stem of an aerosol container valve, the upper portion of said bore constituting an expansion chamber in communication with the valve stem, an axial passage of smaller cross-sectional area than that of the expansion chamber extending from the top surface of the insert member to the expansion chamber, a plurality of radial grooves in the top surface of the insert extending from said axial passage, and a groove extending around the periphery of the top surface and intersecting said radial grooves,

the body member including a discharge orifice extending from the exterior of the body member to said cavity, a swirl generator depression in the cavity wall proximate to and in communication with said discharge orifice, and at least one groove in the cavity wall extending upwardly from said swirl generator depression and thence diametrically across the top wall of the cavity and in communication with said peripheral groove and said axial passage of the insert member.

2. An aerosol valve actuator spray button comprising a body member having a cavity open at the bottom and an insert member occupying said cavity, the insert member having a valve stem receiving socket open at the bottom, an annular passage encompassing the periphery of the top surface of the insert member, a passage in the insert member extending from said valve stem receiving socket to said annular passage, the body member having a discharge orifice extending from the exterior surface of the body member to said cavity, a swirl generator means in communication with the discharge orifice, said swirl generator means being formed in the surface defining the body member cavity, and a passage formed between the juxtaposed surfaces of the body member cavity and the insert member extending from said annular passage to said swirl generator means.

3. The actuator of claim 2 wherein the annular passage is formed at the intersecting edge of the top surface of the insert member, and the passage between the annular passage and the valve stem receiving socket being constituted by at least one radial groove formed in the top surface of the insert member, said groove intersecting an axial aperture in communication with said socket.

4. The actuator of claim 2 wherein the passage leading to the swirl generator means from the annular passage is a longitudinally disposed groove in said cavity wall.

5. The actuator of claim 4 wherein said longitudinally disposed groove is an extension of a diametrically disposed groove formed in the top wall of the cavity of the body member.

6. The actuator of claim 4 wherein the swirl generator means includes a plurality of baffle members which define tangential passages extending from the periphery of the swirl generator means toward the discharge orifice.

7. A valve actuator spray button for a pressurized container comprising, a body member having a cavity, and an insert member located within said cavity, said insert member being provided with a valve stem receiving socket and provided with at least one product flow passage for communicating with the valve stem and extending to the exterior of the insert member, the juxtaposed surfaces of the insert member and of the cavity of said body member having at least one duct formed therebetween, said duct comprising a groove in one of the members cooperating with the adjacent surface of the other member to complete said duct which extends from the product flow passage of the insert member to a swirl generating means including a swirl chamber formed as a depression in the surface of the body member cavity.