Non-clogging Aerosol Valve

Abstract

An improved aerosol valve intended to prevent clogging with salt crystals provides a high velocity turbulent flow through the stem with interior channels gradually increasing in size. The stem orifices break through into a rectangular portion of the stem flow passage which is the same width as the orifices. The capillary attraction of residue fluid by the narrowly spaced walls prevent clogging of the orifices. The concept further includes a spring cup or valve housing wherein the material gradually expands from a restricted entrance opening through a long passage which gradually increases in size. There are no sudden expansion points in the flow path which would be likely to result in formation of crystals either in the valve housing or stem.

Description

The invention is an improved aerosol valve assembly with the general object of avoiding stoppage or clogging at any point in the flow system. It provides for a smooth flow from the restricted entrance leading to the valve housing all the way to the actuator, eliminating points of sudden expansion.

It has been found that conventional aerosol constructions are not successful when used with certain types of materials having a high percentage of metallic salts such as found in antiperspirant preparations. Much trouble has been experienced especially with clogging at the valve stem orifices and also, to a lesser extent, by crystallization in the bottom portion of the spring cup or valve housing.

My invention avoids such causes of failure by novel shapes and construction in the valve stem and valve housing. First, the valve stem provides a smooth flow from the stem orifices into a gradually expanding stem passage so shaped as to provide high velocity turbulent flow, with the side walls of the channel near the orifices being shaped and located so as to pull away from the stem orifices such residue of material as may be left in the stem between actuations of the valve. Secondly, the valve housing has a generally smooth interior wall surface gradually expanding along a relatively long flow channel through the dip tube nipple to a port in the bottom wall of the valve housing. Such port is almost as large as the internal diameter of the bottom portion of the housing leaving only a narrow shoulder to provide a seat for the spring and with the sidewalls of the housing itself being as smooth as possible and tapering gradually to the area of the valve head.

Various other objects and advantages of the invention will hereinafter more fully appear.

In the accompanying drawings, I have shown for purposes of illustration, one embodiment which the invention may assume in practice. In these drawings:

FIG. 1 is a perspective in central section showing the improved valve assembly;

FIG. 2 is a vertical cross section with the valve closed;

FIG. 3 is a vertical cross section with the valve open, the valve itself being shown in side elevation;

FIG. 4 is a fragmentary, vertical section of a portion of FIG. 2, but on a larger scale;

FIG. 5 is a vertical cross section through the valve at right angles to FIG. 4;

FIG. 6 shows a portion of the valve in side elevation with a portion broken away to reveal one of the stem orifices;

FIG. 7 is a top plan view of the valve stem;

FIGS. 8 and 9 are cross sections on lines 8-8 and 9 respectively of FIG. 5.

The improved functional features of the present valve are obtained in a construction having the advantages of tilt action and possibility of fast gassing or filling in accordance with Briechle U.S. Pat. No. 3,158,298. A metal cap 10 has a rolled rim 11 for connection to the mouth of a container and a central pedestal 12 having a top wall 13 with a central aperture 14. An annular valve seat 15 also has a central hole 16 registering with the hole 14 in the cap and is positioned against the underside of the cap wall 13. The valve housing is a one-piece molding of suitable plastic material being generally cup-shaped with a bottom wall 17, a side wall 18 which has a smoothly sloping interior surface 19 leading to a thickened cylindrical portion 20. This portion has ribs 21 around its periphery communicating with the under surface of the cap wall 13 to allow quick filling when the valve seat gasket 15 is pushed down. The wall of the pedestal portion 12 of the cap is indented as indicated at 22 to secure the valve housing to the cap.

The valve member has a head 23 with a slightly dished upper surface 24 so as to allow the corners 25 to seat and seal against the gasket 15 but otherwise avoids the usual well in the top of the valve head. A valve stem 26 projects upwardly from the valve head through the central openings in the valve seat gasket 15 and the opening 14 of the cap and terminates at its upper end in a hollow cylindrical shape 27. There is also indicated an actuator button 28 fitted tightly on the cylindrical surface of the valve stem and having a discharge passage 29. The valve stem is molded with a circumferential groove 30 around the base and this groove is of less height than the thickness of the valve seat gasket 15 so that the gasket can nevertheless form a seal around the stem when the valve is closed.

As to the flow channel or channels in the stem, there is first the rectangular passage 31 leading all the way from the top cylindrical portion 32 through and slightly beyond the groove 30. While the sidewalls of this passage are quite close together, it is wide enough to intersect the groove 30 so as to form two opposed stem orifices 33. A short distance above the groove 30, a pair of gradually enlarging side channels 34 and 35, having flaring surfaces 36 and 37 near the bottom and flaring surfaces 38 and 39 near the top, which surfaces 38 and 39 also widen out to merge with the bore of the cylindrical portion 32. This allows for a high velocity flow especially near the bottom of the stem and avoids any abrupt expansion at any point during the flow through the stem. After the valve has been actuated, there will be a slight amount of fluid left in the actuator button 28 and the stem which may tend to collect around the stem orifices 32 and 33. Due to the fact that the sidewalls of the rectangular passage 31 are closely spaced and lead directly away from the stem orifices, the residue fluid is pulled away from those orifices by capillary attraction as indicated by the meniscus curves 40 where the liquid level might settle.

A nipple 41 extends downwardly from the bottom wall 17 of the valve housing and its outer surface is adapted to receive a dip tube 42. An entrance opening 43 at the bottom of this nipple 41 is necessarily of restricted diameter, something of the order of 0.016 of an inch, so as to meter the flow of fluid. From this orifice, the fluid goes through a relatively long flow passage 44 that gradually expands preferably along smooth, slightly curving sidewalls as indicated in the drawings to a port 45 which opens into the valve housing interior. This port is only slightly smaller in diameter than the interior of the housing wall 18 to provide a narrow shoulder 46 serving as a rest or a seat for a spring 47. This spring acts against the underside of the valve head 23 to urge it against the valve seat 15. The port 45 where the passage 44 opens into the valve housing is several times as large as the restricted entrance opening 43 and preferably at least ten times as large in area. The passage 44 is (as shown) at least about twice as long as the diameter of the port 45. There is, thus, provided an opportunity for gradual expansion of the fluid under the action of the propellant material so that there is no abrupt change such as might cause crystallization where the material enters the valve housing. The smooth flow concept is carried through the valve housing itself and around the valve to the stem orifices 32 and 33 and thence into and through the valve stem itself.

A vapor tap opening is provided preferably as close to the valve as possible. The one herein shown and indicated by the numeral 48 is simply a hole in a small boss 49 formed on the valve housing. The vapor and liquid are now blended just before leaving the valve housing thus minimizing premature mixing of the vapor and liquid.

Claims

I claim:

1. An aerosol assembly which includes

a. a cap to be secured to the mouth of a container and having a central opening;

b. an annular valve seat of resilient material positioned against the underside of said cap in registration with said central opening;

c. a valve having a head adapted to seat against the underside of said valve seat and an integral hollow valve stem projecting upwardly from the head through the openings in said valve seat and cap; and

d. a cup-shaped valve housing surrounding said valve, said housing having a bottom wall and a reduced diameter nipple extending downwardly therefrom adapted for connection with a dip tube and having at its bottom end a restricted fluid entrance opening;

the improvement which consists of a smooth walled flow passage extending from said restricted entrance opening through the length of said nipple and the bottom wall of said valve housing, said passage increasing gradually in size from said entrance opening to a port where it exits through said bottom wall which is more than ten times as large in cross-sectional area as said restricted entrance opening, the passage being at least about twice as long as the diameter of the port, said bottom wall presenting a narrow shoulder surrounding said port, the interior surface of said housing upwardly of said shoulder for the most part tapering smoothly to the region of said valve head and a spring seated on said shoulder and acting against said valve to urge it against the valve seat.

2. The combination defined in claim 1, wherein the internal flow passage of said stem adjacent the head is rectangular in cross section with relatively narrowly spaced side surfaces, one or more stem orifices immediately above said head which merge smoothly into the sides of said rectangular interior channel, and a pair of said channels extending radially outwardly from said side surfaces of the rectangular channel beginning in a region of the valve stem above such orifice or orifices and having sloping surfaces near their bottom ends and flaring outwardly near their upper ends to provide smooth expansion to the upper end of the stem where the cross-sectional area is enlarged to several times that of the flow channel at the bottom end of the stem.

3. In an aerosol valve assembly which includes

a. a cap adapted to be secured to the mouth of a container and having a central opening;

b. an annular valve seat of resilient material positioned against the underside of said cap in registration with said central opening;

c. a valve having a head adapted to seat against the underside of said valve seat and an integral hollow valve stem projecting upwardly from the head through the openings in said valve seat and cap; and

d. a cup-shaped valve housing surrounding said valve;

the improvement wherein said stem has a circumferential groove defining a neck just above said valve head, a flow passage through said stem, which has a rectangular cross section adjacent said head with relatively narrowly spaced sidewalls which intersect said groove to provide a pair of stem orifices, said flow passage beginning a substantial distance above said orifices, having side channels shaped to avoid abrupt changes in cross-sectional areas of the flow passage, said side channels and said rectangular channel merging into a cylindrical bore at the top end portion of the stem to provide high velocity turbulent flow with smooth expansion in the stem area, and wherein the sidewalls of said rectangular channel serve by capillary attraction of residue fluid, to prevent accumulation at the base of the stem and clogging of the stem orifices.

4. The combination defined in claim 3 wherein the spacing of the sidewalls in the lower portion of said stem flow passage which is of rectangular cross section is of the order of one sixty-fourth of an inch.