BACKGROUND OF THE DISCLOSURE
1. Field of Disclosure
The present disclosure is related to the field of aerosol delivery of high-solids product formulations. More particularly, the present disclosure relates to an aerosol valve having a valve stem and compression spring geometry that create shorter flow paths/fewer changes in flow direction to minimize agglomeration of solids in the flow paths and thereby reduce product failures.
2. Description of Related Art
Valve structures for product formulations that have a high solids content can fail due to agglomeration of the solids in the flow passages in the internal space of the valve stem housing. Existing designs of such valves typically employ flow paths that have long, narrow channels, abrupt changes in flow direction, and areas of recirculation flow any of which can cause the solids in the product formulation to agglomerate and clog the flow paths.
As used in this application, agglomeration (or any of its forms) is used interchangeably with clumps (or any of its forms) without a change in meaning.
Also, existing aerosol valves have a compression spring that is fully compressed (i.e., the individual coils are pressed together) when the valve stem is fully pressed by the consumer to spray the product. However, the compressed coils act as a barrier to the product formulation that is passing upward, and so forces the product formulation to follow a flow path that is nearly entirely on the outside of the fully-compressed spring, since there is little or no space between the individual coils that allow the product formulation to flow in the space in the center of the spring.
SUMMARY OF THE DISCLOSURE
The present disclosure is an aerosol valve that provides a free flow aerosol delivery of high-solids product formulations with reduced agglomeration and product failure from clogging.
The aerosol valve of the present disclosure includes a valve stem that has large cross-section passageways that allow the product formulation to flow directly from the dip-tube through the center of the compression spring. This configuration allows the product flow to be gently deflected around the valve stem, which reduces back pressure (resistance).
The valve stem and compression spring geometry of the present disclosure creates a shorter flow path, and a flow path that fewer changes in flow direction, as compared with conventional aerosol valves.
The valve stem of the present disclosure also has large cross-section flow passageways that minimize drag of product flow in the passageways.
These shorter, large cross-section, non-tortuous flow paths of the aerosol valve of the present disclosure minimize agglomeration of solids in the flow paths, and reduce product failure from blockage of the flow paths, even when used for difficult high-solids product formulations.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 (Prior Art) is a conventional aerosol valve in full stroke, illustrating the flow paths around the outside of the springs.
FIG. 2 is a side view of an exemplary embodiment of an aerosol valve of the present disclosure.
FIG. 3 is a cross-section of the aerosol valve in FIG. 2 in a closed (resting) position.
FIG. 4 is a three-quarters-perspective view of the cross-section of the aerosol valve in FIG. 3 in a closed (resting) position.
FIG. 5 is a perspective view of an exemplary embodiment of a valve stem of the present disclosure.
FIG. 6 is a bottom view of the valve stem in FIG. 5, illustrating the cross-shaped configuration of the four (4) flow passageways.
FIG. 7A is another perspective view of the valve stem in FIG. 5, but adding the compression spring to show its position in relation to the four (4) flow passageways and aerosol valve. FIG. 7B is the identical view shown in FIG. 7A, with shading to clearly show the compression spring.
FIG. 8A is another bottom view of the valve stem in FIG. 6, but adding the compression spring to show its position in relation to the four (4) flow passageways and aerosol valve. FIG. 8B is the identical view shown in FIG. 8A, with shading to clearly show the compression spring.
FIG. 9 is a perspective view of a cross-section of the aerosol valve in FIG. 2 in mid-stroke, illustrating primary and secondary flow paths, upon partial compression of the compression spring.
FIG. 10 is a side view of a cross-section of the aerosol valve in FIG. 2 in full stroke, without showing the flow paths.
FIG. 11 is a perspective view of a cross-section of the aerosol valve in FIG. 8 in full stroke, illustrating the primary and secondary flow paths, upon full compression of the compression spring.
DETAILED DESCRIPTION OF THE DISCLOSURE
FIG. 1 is a conventional aerosol valve generally represented by reference numeral 10. Valve 10 is illustrated in FIG. 1 in full stroke, illustrating the long, tortuous flow path of the product formulation around the outside of the compression spring before the formulation is able to enter the center hole of the valve stem.
Aerosol valve 10 includes a dip tube 12, valve stem 16, valve stem housing 18, mounting cup 20, seal 22, and compression spring 32. Valve stem 16 is enclosed in valve stem housing 18. Valve stem 16 has a pair of apertures (not shown in FIG. 1) through which a pressurized high-solids product formulation passes in order to enter center hole 24 of valve stem 16. Mounting cup 20 orients and stabilizes aerosol valve 10 in its proper position on the product. Valve stem 16 contacts compression spring 32 at contact point 26.
Compression spring 32 exerts an upward pressure on valve stem housing 18, which is pressed against seal 22 that is located on the inner aspect of mounting cup 20. Valve stem 16 has an upper portion that protrudes through seal 22 and mounting cup 20, and which is pressed by the consumer to spray the product formulation.
When valve stem 16 is pressed down by the consumer to spray the product, the product formulation flows upward through the internal space of valve stem housing 18 in a flow path 30.
As shown in FIG. 1, compression spring 32 is fully compressed, pushing together the individual coils of compression spring 32 so there is little or no space between any of the individual coils. In this configuration, the coils of compression spring 32 act as a barrier to the space that is inside the compression spring, requiring the product formulation to travel upwardly by a long path through valve stem housing 18 almost entirely along the outside of compression spring 32. This long, tortuous primary flow path 30 increases the probability that the solids in the product formulation will agglomerate and clog the flow path, causing the passage of the product formulation in the flow path to be slowed or blocked altogether, leading to product failure.
FIGS. 2 through 9 illustrate an exemplary embodiment of an aerosol valve 40 of the present disclosure. Referring to FIGS. 2 to 4, aerosol valve 40 includes a dip tube 42, compression spring 44, valve stem 46, valve stem housing 48, mounting cup 50, and seal 52. Valve stem 46 is enclosed in valve stem housing 48. Valve stem 46 has a valve stem aperture 58 through which a pressurized high-solids product formulation passes in order to enter center hole 54 of valve stem 46. Mounting cup 50 orients and stabilizes aerosol valve 40 in its proper position on the product. Valve stem 46 contacts compression spring 44 at contact point 56.
Compression spring 44 exerts an upward pressure on valve stem housing 48, which is pressed against seal 52 that is positioned on an inner aspect of mounting cup 50. Valve stem 46 has an upper portion that protrudes through seal 52 and mounting cup 50, and which is pressed by the consumer to spray the product formulation.
Seal 52 is a flexible material that seals the space between mounting cup 50 and valve stem housing 48. Seal 52 is preferably made of rubber or similar flexible material. Seal 52 is preferably shaped as a gasket. A seal between seal 52, valve stem housing 48 and mounting cup 50 occurs by compression during crimping of cup 50. Pressing on valve stem 46 can somewhat deform the gasket-like seal between seal 52 and valve stem housing 48 as well as between seal 52 and mounting cup 50.
Dip tube 42 is the access point for the stored product formulation in the container (not shown) to aerosol valve 40.
Aerosol valve 40 has fewer abrupt changes in flow direction, as compared with the flow paths of aerosol valves in the prior art. This reduces the propensity of the solids in the product formulation to agglomerate in the flow paths, by providing fewer loci at which the particles may accumulate, and thereby reduces product failures.
FIGS. 5 and 6 illustrate an embodiment of valve stem 46 having four (4) passageways 64, 66, 68, 70 that are perpendicular to each other. Passageways 64, 66, 68, and 70 are large in cross-section to minimize drag and thereby reduce agglomeration of the solids in the product formulation as the product passes through, reducing the incidence of product failure.
The passageways readily allow the product formulation to flow directly from dip tube 42 through the center space inside compression spring 44 (shown clearly in FIGS. 3 and 4), and to be gently deflected around valve stem 46. Valve stem 46 is preferentially a thinned valve stem body. These structures and configuration reduce back pressure (resistance) to the flow of the product formulation before it reaches valve stem aperture(s) 58. This is an advantage over conventional valve flow paths, which require abrupt changes in flow direction and passage through long, narrow channels prior to arriving at the valve stem apertures.
Aerosol valve 40 preferentially forms the largest possible flow path cross-sections that are viable, given the constraints of the valve stem housing, compression spring geometry, and valve stem molding capability (for strength and moldability). In an exemplary embodiment, expressed as the % cross section of the flow paths (passageways) versus the full inside diameter of the compression spring coils, about 49% of the available cross-section inside of the compression spring coils is divided into the four passageways.
FIG. 7A illustrates a view of aerosol valve 40 that shows the position of compression spring 44 in relation to passageways 64, 66, 68, 70. Compression spring 44 is shown in FIG. 7A as fully-compressed (open), as the spring would be when aerosol valve 40 is fully-actuated. FIG. 7B is an identical view to FIG. 7A, but with shading to clearly illustrate these components.
FIG. 8A illustrates another view of aerosol valve 40 to show the position of compression spring 44 in relation to passageways 64, 66, 68, 70. Compression spring 44 is shown as fully-compressed in FIG. 8A, as the spring would be when aerosol valve 40 is fully-actuated. FIG. 8B is an identical view to FIG. 8A, but with shading to clearly illustrate these components.
FIG. 9 illustrates valve 40 in mid-stroke, which is an intermediate, short-lived position of the valve as the valve transitions from an unactuated (closed) position to its fully-actuated (open) position when the valve stem is pressed by the consumer to spray the product. While the valve is in this intermediate position, the product formulation is propelled upward primarily by primary flow path 60 through the center of compression spring 44. However, in this brief transition time, some of the product formulation is moving around spaces 45 between the coils of compression spring 44 in secondary flow path 62.
FIGS. 10 and 11 show a cross-section of valve 40 in its fully-actuated position. Valve stem 46 fully compresses compression spring 44, which reduces or eliminates spaces 45 between the coils. Thus, as shown clearly in FIG. 11, at full-stroke, nearly all (or all) of the product formulation moves upward in aerosol valve 40 through the center of compression spring 44, which is shown as primary flow path 60. Primary flow path 60 is shorter and less tortuous as compared with the flow paths in existing aerosol valves (for example, as compared with the primary flow path 30 in the prior art described above). This shorter, less tortuous flow path reduces the likelihood of agglomeration of the solids in the product formulation, and reduces produce failures.
As shown in FIG. 11 (as well as in FIGS. 7A-7B and 8A-8B), the geometry of compression spring 44 and large passageways 64, 66, 68, 70 direct the ingress of the product formulation to flow upward almost exclusively along primary flow path 60 through the center of compression spring 44, and to exit the upper end of compression spring 44 still within the space circumscribed by the spring coils.
Conversely, as also shown in FIG. 11, the interaction between valve stem 46 and compression spring 44 when valve 40 is actuated allows very little or none of the product formulation to move upward via secondary flow path 62, which is a path along the outside of compression spring 44 and between the individual coils. Again, this is because there is little or no space between individual coils when the aerosol valve is fully actuated. Since there is much less of the product formulation moving along this longer, tortuous (secondary) route, there is reduced incidence of agglomeration of solids in the flow paths and, consequently, fewer product failures.
In an exemplary embodiment, the product formulation of the present disclosure is a mixture of two types of media, such as a mixture of a powder (solids) and propellant.
EXPERIMENTAL
Testing the proposed aerosol valve with high-solids product formulations has resulted in no recordable instances of failure of the product to dispense throughout full-life testing. This is in contrast to laboratory testing with known, existing aerosol valve designs that failed due to agglomeration with a difficult, high-solids formulation that showed a propensity to agglomerate.
A method of using the free flow aerosol valve described above for delivery of high-solids product formulations is also provided. The method uses the aerosol valve having shorter flow paths, fewer direction changes, and larger passageways as compared with existing aerosol valves to minimize agglomeration of solids in the flow paths and reduce product failures due to, for example, blockage of flow paths.
As used in this application, the word “about” for dimensions, weights, and other measures means a range that is ±10% of the stated value, more preferably ±5% of the stated value, and most preferably ±1% of the stated value, including all subranges therebetween.
It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications, and variances that fall within the scope of the disclosure.
Patent Application
20150274403
