What I claim is
1. In a plug valve assembly for dispensers of fluid products adapted to be attached to a product container for containing the fluid product to be dispensed and adapted to accommodate a propellant cartridge containing particles of adsorbent material within the product container, said plug valve assembly having a hollow valve stem, a pushbutton actuator on the upper end of said stem and having a nozzle therein communicating with said hollow stem, a cap member adapted to fit over a product container and having an aperture therein through which the hollow stem is movable, a support secured to the underside of said cap and having a hollow central interior through which said hollow stem is movable, means in said support opening into said hollow interior for admitting the product to be dispensed, a fluid product flow path through said hollow stem exteriorly of the hollow thereof from a point adjacent said hollow interior, a first flexible gasket means in said assembly through which said hollow stem passes obturating said fluid product flow path between said fluid product flow path and said hollow interior, said support having a downwardly open recess therein, a second gasket means in the bottom of said recess through which said hollow stem passes, said hollow stem having an aperture therein opening into the hollow of the stem, said aperture being obturated by said second gasket means, and a propellant cartridge on the support opposed to the downwardly open recess, that improvement comprising a retaining ring having a tubular portion extending generally downwardly and then flaring outwardly, the upper end of said tubular portion being engaged with said second gasket means and holding said second gasket means in said recess, the flared portion having an outwardly extending flange therearound in tight engagement with said cartridge, said retaining ring having a downwardly extending annular cutting edge on the lower end of said downwardly and outwardly flared portion, and a disc-shaped filter element secured in said annular cutting edge and against the bottom of said retaining ring for filtering out particles of adsorbent material which may be entrained in the propellant.
2. A retaining ring adapted to be assembled with a disc-shaped filter element and for positioning between the top of a container containing particles of adsorbent material and a stem-obturating gasket in an aerosol-type dispenser, said ring comprising a generally tubular upper portion, a downwardly and outwardly flaring portion on the lower end of said tubular portion, an upwardly and outwardly curved portion on the end of said flaring portion, an outwardly extending flange on the end of said upwardly and outwardly curved portion, and a downwardly extending annular cutting edge on the lower edge of said downwardly and outwardly flared portion.
3. A retaining ring assembly for positioning between the top of a container containing particles of adsorbent material and a stem-obturating gasket in an aerosol-type dispenser, said assembly comprising a retaining ring having a generally tubular upper portion, a downwardly and outwardly flaring portion on the lower end of said tubular portion, an upwardly and outwardly curved portion on the end of said flaring portion, an outwardly extending flange on the end of said upwardly and outwardly curved portion, and a downwardly extending annular cutting edge on the lower edge of said downwardly and outwardly flared portion, and a disc-shaped filter element secured in said annular cutting edge and against the bottom of said retaining ring.
4. A method of preparing an assembly of a retaining ring and a disc-shaped filter element for mounting between the top of a container containing particles of adsorbent material and a stem-obturating gasket in an aerosol-type dispenser comprising dipping the lower portion of a retaining ring having a generally tubular upper portion, a downwardly and outwardly flaring portion on the lower end of said tubular portion, an upwardly and outwardly flaring portion on the lower end of said tubular portion, and upwardly and outwardly curved portion on the end of said flaring portion, and outwardly extending flange on the end of said upwardly and outwardly curved portion, and a downwardly extending annular cutting edge on the lower edge of said downwardly and outwardly flared portion, into an adhesive, then pressing the thus-dipped retaining ring onto a sheet of filter material and forcing the cutting edge through the material to cut a disc-shaped filter element from the sheet of filter material, whereby when the retaining ring is lifted from the sheet of filter material, the disc-shaped filter element is retained in the annular cutting edge and is adhered thereto and to the bottom of the retaining ring.
This invention relates to a plug valve assembly for dispensers of fluid products in which a high-pressure gasket means in the bottom of the plug valve assembly is held in position by a retaining ring, the retaining ring being of a flexible metal and being secured to the assembly, a propellant cartridge containing a liquefied gas adsorbed or absorbed in particles of silica gel or some similar materials, the cartridge being secured in gastight relationship to said retaining ring, and a filter between the cartridge and the retaining ring. The term adsorption will be used hereinafter to designate both adsorption and absorption, as well as a combination thereof, when discussing the taking up of the propellant gas by such particles.
There is already known in the art a pushbutton dispenser for dispensing a fluent product constituting an active agent in fractional amounts and in a spray, by means of a propellant gas under pressure adsorbed in a material such as silica gel in a propellant cartridge placed inside the product container which contains said fluent product, and which cartridge is carried on said support, which support is integral with a cover which seals off the aforementioned product container. This integral support and cover contains a high-pressure obturating means for the propellant cartridge and a low-pressure obturating means controlling at least the passage of the product from the container to the pushbutton spray nozzle and in some instances the passage of air from the outside to the inside of the product container. A stem which conducts the propellant and the product in the direction of the spray nozzle is slidably mounted in said support and controls the aforementioned obturating means. This dispenser has the high-pressure obturator mounted in the bottom of the support which is held therein by a substantially rigid retaining ring.
The high-pressure obturator is positioned in a recess in the support which opens toward the propellant cartridge, said obturator being held in said recess by means of the retaining ring member which also forms part of the closure for said propellant cartridge. The retaining ring member consists of a separate annular part which is forced into a recess in the support and has a downwardly and outwardly extending portion positioned between the support and the collar of the propellant cartridge. In dispensers of this type, if silica gel or a like adsorbent is used in the propellant cartridge, the possibility exists for small particles of the adsorbent to leave the cartridge, pass through the stem and clog the propellant orifice. In order to eliminate this possibility, a filter of some sort is desirable between the propellant cartridge and the opening through the valve assembly which gives access to the stem.
A desirable place for a piece of filter material would be across the retaining ring which holds the obturator for the valve stem in the recess in the support. However, in order to make sure that the filter stays in place, it should be secured to the retaining ring. The easiest way to do this is to secure it by means of adhesive. The drawback in this manner of securing it is that at least three operations are involved, first the cutting out of the piece of filter material to the appropriate size and shape, applying adhesive to the retaining ring, and then bringing the filter and the retaining ring together to adhere them to each other.
Because dispensers of the type in question must be produced as inexpensively as possible, it is necessary to reduce the number of operations involved in their manufacture and assembly to a minimum.
It is, therefore, an object of the present invention to provide a method of manufacturing and assembling a filter in a dispenser having adsorbent material in the propellant cartridge, which method reduces to a minimum the number of operations involved.
It is a further object of the invention to provide a retaining ring which can be used to carry out this method, and a dispenser including the retaining ring.
These objects are accomplished by providing a retaining ring of aluminum or a like metal which holds the high-pressure gasket in the downwardly open recess in the bottom of the plug valve assembly, the retaining ring having the lower outer edge secured in gastight relationship to the propellant cartridge, and the retaining ring pressing against the high-pressure gasket in the recess. At the lowermost portion of the retaining ring is an annular cutting edge which projects downwardly from the retaining ring when the dispenser is in the upright position.
In use, the retaining ring is first coated with adhesive around the inside of said cutting edge, and then it is pressed onto a sheet of filter material to cut from the filter material a filter which fits exactly into the cutting edge. When the retaining ring is lifted from the sheet of filter material, it carries with it the cutout disc-shaped filter element, and there results an assembly of the retaining ring and the filter element which is ready to be positioned in the dispenser with the filter in position between the propellant cartridge and the opening into the valve stem.
Other features and advantages of the present invention will be brought out in the following description and accompanying drawings, in which:
FIG. l is a sectional view of a dispenser of the type in which the invention is incorporated;
FIG. 2 is an axial sectional view of the upper part of an embodiment of the dispenser according to the present invention;
FIG. 3 is a view similar to FIG. 2 showing the parts in the dispensing positions;
FIG. 4 is a sectional elevation view of the retaining ring;
FIG. 5 is a sectional elevation view of the assembly of the retaining ring and filter; and
FIGS. 6a--6d are views of the operations for forming the assembly of FIG. 5 .
Referring to FIGS. 1 and 2 of the attached drawings, the dispenser comprises a product container C which is adapted to hold a flowable product such as a liquid or a finely divided powder. The product container is closed by a cover or cap member 1 from which depends the plug valve assembly. A propellant cartridge 43 depends from the plug valve assembly into the interior of the container C. The cover 1 is made, for example, of plastic material to which support 2 is attached, these parts mutually abutting each other at a joint 3 where they fit together and hold therebetween a flexible annular low-pressure sealing gasket 4 which is the low-pressure obturator for the active agent and the low-pressure obturator for the admission of air to the product container C from the outside. Parts 1 and 2 may be attached to each other, for example, by ultrasonic welding.
Cover 1 has a central opening 5 and support 2 has an axial valve cup 6 therein, which opening and valve cup are traversed during the axial stroke of valve stem 7 connected to a valve actuator in the form of a pushbutton 8 containing a nozzle insert 9 having a venturi-type spray nozzle therein. Nozzle insert 9 is set into cavity 11 in the head of pushbutton 8. An aperture 12 defined by a shoulder 16 is provided between valve cup 6 and a diverging recess 13 in the base of support 2.
The high-pressure obturator is in the form of an annular gasket 15 mounted in a downwardly opening recess 65 in support 2. The aperture 12 from the valve cup 6 opens into recess 65, which in turn opens into recess 13.
Valve stem 7 is made in one piece, for example, by molding, and has an axial channel 17 with the conical head 18 closing one end thereof. The valve stem 7 extends through aperture 12 to permit the passage of the propellant therethrough. Radial apertures 19 in the wall of valve stem 7 adjacent the head 18 are closed by the inner peripheral edge of gasket 15 when the valve stem is in the undepressed condition.
Gasket 15 is held in recess 65 by a retaining ring 66. The latter is an independent member of a flexible, deformable and at least slightly resilient material, preferably metal, such as aluminum, and which has a central generally tubular portion 66c flared downwardly and outwardly at 66d, somewhat in the shape of a truncated cone, as shown in FIG. 4. The tubular portion 66c of the retaining ring has a central hollow 67 through which the cone-shaped head 18 of valve stem 7 extends. The upper edge of the tubular portion 66c can be relatively sharp so as to dig into the gasket 15 slightly. Alternatively, a shoulder 66b can be formed by the bent over upper edge of the tubular portion 66c, as shown in FIG. 4, which shoulder 66b bears on gasket 15.
A cylindrical cavity 70 is defined at the lower end of support 2 by an annular flange 68. The peripheral edge of the lower end of retaining ring 66 is curved upwardly and outwardly at 66a to a flange 71 seated against the lower edge of annular flange 68. A sealing gasket 101, for example a flowed in gasket or a preformed ring-shaped gasket of a synthetic rubber material such as Buna-N, a synthetic rubber formed by copolymerization of butadiene and acrylonitrile sold by I.G. Farben Industries, or Neoprene, a long-chain synthetic rubber made by polymerization of chloroprene, and sold by DuPont, is held between the flange 71 and collar 69 of propellant cartridge 43. The terminal portion of the propellant cartridge is bent so as to fit closely to the contour of annular flange 68, flange 71 and gasket 101, forming a tight joint at the top of the propellant cartridge 43. The retaining ring 66 is made of a material which is impermeable with respect to the propellant contained in propellant cartridge 43. This prevents leaks as a result of permeability through the material of support 2.
At the lower end of the downwardly and outwardly flared portion 66d is an annular cutting edge 66e which projects downwardly from the retaining ring 66 when the dispenser is in the upright position. Secured in the annular cutting edge 66e and against the bottom of the retaining ring is a disc-shaped filter element 102 which can be made of any conventional filter material which is inert to the propellant and which is porous or permeable by the propellant. Preferably the edge of the filter element and the peripheral portion of the upper surface are adhered to the inner surface of the cutting edge and the bottom of the retaining ring, respectively. Since the retaining ring 66 seals off the space within the cartridge 43 from the space in the bottom of the valve assembly so that propellant is directed into the aperture 19 at the bottom of the valve stem 7, the filter element covers the entire cross section of the flow path of the propellant, and therefore will filter out of the gaseous propellant any particles of adsorbent material which might be present in the propellant.
The filter element 102 can be cut and assembled with the retaining ring 66 in a very simple and efficient operation so that the assembly can be positioned in the dispenser without any separate assembly step for the filter element. As shown in FIGS. 6a--6d, the retaining ring formed with the annular cutting edge 66e thereon is first dipped into an adhesive A, as shown in FIGS. 6a and 6b . Thereafter, as shown in FIGS. 6c and 6d, it is positioned above a sheet F of material of which the filter element 102 is made, and then urged downwardly against the sheet F so that the cutting edge 66e cuts through the sheet F to cut a filter element out of it. The presence of the adhesive on the cutting edge and the bottom of the retaining ring together with the slight compression of the material of the filter element within the cutting edge due to the thickness of the cutting edge will cause the filter element to be retained within the cutting edge on the retaining ring when the retaining ring is withdrawn from the sheet F. Thereafter, when the adhesive sets, the filter element will be firmly secured in the retaining ring. There is thus obtained an assembly of a retaining ring 66 and a filter element 102, which is ready for assembly into the dispenser as a unit.
The dispenser is assembled by first mounting the plug valve assembly on the underside of the cover 1, and with the gasket 15 positioned in the recess 65. The propellant cartridge is then filled with the particles of adsorbent. The assembly of the retaining ring 66 and filter element 102 of the present invention is then positioned between the top of the propellant cartridge 43 and the gasket 15, and the particle-filled propellant cartridge 43 and the plug valve assembly are moved toward each other so as to tightly press the sealing gasket 101 and the flange 71 between it and the flange 68 on the lower end of the support 2, and with the parts held in this position, the remainder of the collar 69 is bent around the upper edge of the flange 68. This insures the tight holding of the propellant cartridge to the plug valve assembly.
The cover 1 can then be placed on the product container C and the apparatus can be filled with the product to be dispensed in the conventional manner. The propellant gas under pressure is forced into the cartridge where it is adsorbed in the adsorbent particles.
A flange 24 on valve stem 7 is urged upwardly by a spring 25 around valve stem 7, and is positioned between flange 24 and the bottom of cup 6. This spring acts to press the flange 24 upwardly so that the flexible lip of gasket 4 is held between a truncated cone-shaped surface 26 on flange 24, cambered as shown in FIG. 2, and an annular projection 28 around the edge of opening 5 in cover 1. This provides a tight closure of valve cup 6 with respect to opening 5.
Pushbutton 8 which caps valve stem 7 has two coaxial sockets at the base thereof: an outer socket 73 defined by depending wall 22 and which fits tightly around valve stem 7, and an inner socket 74 which receives the tapered end 75 of stem 7. The extent to which sockets 73 and 74 can be forced along valve stem 7 is limited by an annular shoulder 76 at the base of fins 72 defining between them channels 21, along the outside of the stem 17. The channels open out of the stem through apertures 23.
The surface 78 of said flange 24 opposite gasket 4 is straight and serves as a support for spring 25, but this flange 24 also serves as a movable stop for the pushbutton assembly. Fixed radial stops 82 are provided inside cup 6. If pushbutton 8 is pushed in too far, its travel is limited by the contact of surface 78 with stops 82.
Into valve cup 6 opens means for admitting the product to be dispensed, for example the upper end of a dip tube 29, force-fitted in a bore 31 in support 2. Alternatively, this means can be a bag adapted from a flexible bag or sac containing the product to be dispensed.
When valve stem 7 is in the undepressed position, as shown in FIG. 2, a tight closure is also insured between opening 5 which communicates with the outside atmosphere as a result of a clearance provided for the sliding movement of the valve stem and the space under the cover 1, which is in communication with the upper surface of gasket 4 through at least one radial channel 32 in the lower face of the downwardly depending portion from cover 1.
When valve stem 7 is in this position, the inner peripheral edge of gasket 15 closes apertures 19 and tightly engages valve stem 7 so that a tight closure is insured between aperture 12 and the interior of propellant cartridge 43.
In operation, with the pushbutton depressed and the parts in the positions shown in FIG. 3, the propellant will flow through the hollow stem 7 and through the nozzle in the pushbutton and will aspirate the product to be dispensed through the dip tube 29, the channels 21 and into the nozzle. Because the filter element 102 is positioned across the flow path of the propellant, it will filter out of the propellant any of the particles of adsorbent material which may have been entrained therein.
It will, therefore, be seen that there has been provided a retaining ring and filter element assembly which can be easily fabricated and assembled in the container and plug valve assembly. It is not necessary to prepare filter elements 102 separately, coat them with adhesive, or alternatively coat the appropriate surface of the retaining ring, and then properly position the filter element on the retaining ring and hold it in place while the adhesive sets. Two simple steps suffice for both forming the filter element and assembling it with the retaining ring, the first being the coating with the adhesive, and the second being the pressing against the sheet of filter material to cut the filter element therefrom and simultaneously position it on the retaining ring. The retaining ring in effect acts as the die punch for the filter element, and makes possible the combining of the two separate steps of cutting the filter and then placing it on the retaining ring in a single step.