US3451596A

US3451596A - Integral plug valve assembly for dispenser of products in the fluid state

Info

Publication number: US3451596A
Application number: US686009A
Authority: US
Inventors: Jean Marand
Original assignee: Geigy Chemical Corp
Current assignee: Novartis Corp
Priority date: 1966-11-28
Filing date: 1967-11-28
Publication date: 1969-06-24
Anticipated expiration: 1986-06-24
Also published as: ES365337A2; DE1915368A1; CH521799A; BE730234A; FR2004901A6; US3589618A; GB1267497A; LU58310A1; FR1532270A

Description

June 24, 1969 J. MARAND 3,451,596

INTEGRAL PLUG VALVE ASSEMBLY FOR DISPENSER OF PRODUCTS IN THE FLUID STATE Sheet Filed NOV. 28, 1967 1 J I 1 L6 L7 2 2.2 H

s M mi I ll. I I I FIG! INVENTOR JEAN MARAND D E F ATTORNEYS Sheet June 24, 1969 MARAND INTEGRAL PLUG VALVE ASSEMBLY FOR DISPENSER 0F PRODUCTS IN TEE FLUID STATE Filed Nov. 28, 1967 J. MARAND June 24, 1969 INTEGRAL PLUG VALVE ASSEMBLY FOR DISPENSER OF Sheet Filed Nov. 28, 1967 y mm I it'll KR III o I 8 J INVENTOR JEAN MARAND ATTORNEYS 3,451,596 ER 0F J. MARAND June 24, 1969 INTEGRAL PLUG VALVE ASSEMBLY FOR DISPENS PRODUCTS IN THE FLUID STATE Filed NOV. 28, 1967 Sheet m m D N MA R A M N A E v ATTORNEYS United States Patent Int. Cl. B67d 5 /54; A62c 13/34 US. Cl. 222193 13 Claims ABSTRACT OF THE DISCLOSURE 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 within the product container, said plug valve assembly comprising a hollow valve stem, 2. 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 under side of said cap and having a hollow central portion through which said hollow stem is movable, a dip tube secured in said support and opening into said hollow interior, 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 stern passes obturating said fluid product flow path between said fluid product flow path and said hollow interior, a second flexible gasket means in the bottom of said support through which said hollow stern passes, said hollow stern having an aperture therein opening into the hollow of the stern, said aperture being obturated by said second flexible gasket means, and means on said support to which a propellant cartridge can be secured in gas tight relationship to said support.

This invention relates to a pushbutton type dispenser for fractional dispensing in spray form of a fluent phase, i.e. liquid or powdered, product by means of a fluid propellant consisting of compressed or preferably liquefied gas, said propellant being held in a propellant cartridge that keeps it completely separate from the fluent product to be dispensed.

Dispensers of the above type are already known and are used in particular in the making or aerosol bombs in which the propellant cartridge is housed inside an outer product container that holdes the fluid product to be dispensed.

Specifically, according to US. Patent 3,289,949, for example, the dispenser is so designed that the propellant cartridge, which placed inside the product container holding the active agent, is supported on a stopper that closes otf the top of this container. Said stopper contains a high pressure obturator means for the propellant cartridge chamber and pressure obturator means controlling respectively the passage of the active agent from the product container to the spray nozzle in the pushbutton actuator therefor and the passage of air from the outside to the inside of the container. The stem of the pushbutton which permits the propellant and the active agent to travel to the spray nozzle is mounted so that it slides in said stopper and controls the aforementioned obturator means.

The stopper and its attachments constitute a subassembly that can support the propellant cartridge and which may be mounted on various containers. This inven- 3,451,596 Patented June 24, 1969 tion relates to dispensers of the type in question, which have in particular made it possible to increase appreciably the area of applications of aerosol bomb type units.

The improvements covered by this invention are intended to facilitate the industrial manufacture of dispensers of the type in question and to reduce their cost. They are also intended to permit assembly of the components on automatic machines and the filling of the dispenser by means of conventional filling machines.

Another purpose of the invention is to provide a dispenser which performs well in producing a fine spray and which eliminates droplets at the start and end of the operation. A further purpose of the invention is to provide a dispenser which will carry out an even and complete emptying of the product container holding the active agent, in keeping with optimum efiiciency for the propellant.

According to the invention, the dispenser has an integral product container cover and support to which the propellant cartridge is attached and the high pressure obturator means is mounted in the support of this assembly.

This arrangement, which makes it possible to integrate the high pressure obturator and the support has, as will be seen, important technical consequences.

According to a preferred embodiment of the invention, the high pressure obturator is a gasket held between a shoulder on the support and surrounding an aperture for the passage of a valve stem connected with the pushbutton, and a ring which is force-fitted in a seat in this support.

Under these conditions, it is advantageous to have the propellant cartridge directly attached on the outer circumference of the support and in particular to have the neck of the propellant cartridge secured over a flange on the support.

This arrangement greatly facilitates the assembly and subsequently the filling of the propellant cartridge.

The annular type high pressure obturator can either be of the yielding type which bends under the action of a shoulder on the valve stem, or of the fixed type, in which case the valve stem slides through it.

According to a preferred embodiment of the invention, the valve stem has an axial channel for passage of the propellant and an annular channel therearound, or a plurality of longitudinal channels therealong, for passage of the product. When the pushbutton is actuated, these two channels are placed in communication respectively with the propellant cartridge and a recess supplied with active agent to be dispensed through apertures.

In particular, the valve stem can advantageously be a one-piece stem and can be attached at one end to the spray apertures in the pushbutton head.

Other features of the invention will become clear from the following description, taken together with the accompanying drawings, in which:

FIG. 1 is an axial sectional view showing one embodiment of the assembly and its various parts in an undepressed or non-dispensing position;

FIG. 1a is a sectional view taken on line 1a-1a of FIG. 1;

FIG. 2 is a corresponding view on a smaller scale showing the assembly of FIG. 1 in a dispenser;

FIG. 3 is a sectional view similar to FIG. 1 with the parts in the depressed or dispensing position;

FIG. 4 is an axial sectional view of a second practical embodiment of the assembly with the parts in the undepressed position;

FIG. 5 is a similar view of the embodiment of FIG. 4 with the parts in the depressed position;

FIG. 6 is an axial sectional view of another embodiment of the assembly with the parts in the undepressed position;

FIG. 7 is a similar view of the embodiment of FIG. 6 with the parts in the depressed position; and

FIGS. 8 through are diagrams relating to the operation of the assembly.

Referring to FIG. 1 of the attached drawings, the integral product container cover and support for a dispenser according to the invention has a cover 1 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 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 is provided between valve cup 6 and a diverging recess 13 in the base of support 2.

In the bottom of valve cup 6 and extending around the aperture 12 is an upwardly projecting flange 14 against which rests a flexible annular high pressure sealing gasket 15 which is held between the flange 14 and a ring 16 which is force-fitted in the bottom of valve cup 6.

Valve stem 7 is made in one piece, for example by molding, and has an axial channel 17 with a conical head 18 closing one end thereof. The valve stem 7 extends through aperture 12 to permit passage of the propellant therethrough. Radial apertures 19 in the wall of valve stem 12 adjacent the head 18 are closed when the valve stem is in the undepressed condition by the flexible lip of gasket 15, the center opening of which is closed by head 18. A shoulder is formed at the upper edge of the openings 19 which bears on gasket 15.

At the upper end, i.e., the end opposite the head 7, the valve stem 7 also has, around channel 17, an annular ring of longitudinal channels 21, the outer wall 22 depending from pushbutton 8 and having apertures 23 therein adjacent a plug 24 which is positioned within valve cup 6 beneath gasket 4 with respect to the opening 5. The edges of apertures 23 extend obliquely to form shoulders, and the annular inner edge of gasket 4 engages under the shoulders adjacent apertures 23.

Plug 24 is urged upwardly by a spring 25 around valve stem 7 and is positioned between plug 24 and ring 16. This spring acts to press the plug 24 upwardly so that the flexible lip of gasket 4 is held between a truncated cone shaped shoulder 26 on plug 24, cambered as shown in 'FIG. 1, 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.

Into valve cup 6 opens the upper end of dip tube 29, force-fitted in a bore 31 in support 2 and which is for the passage of the active agent.

When valve stem 7 is in the undepressed position, 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 lip of gasket 15 is pushed by the head 18 of the atomizer against ring 16, closing apertures 19' in such a way that a tight closure is insured between aperture 12 and axial channel 17.

The maximum outside diameter of head 18 is preferably larger than the inside diameter of the aperture in the bottom of ring 16. This prevents the stem 7 from being blown out through the support 2 if excess pressure builds up in cartridge 43, yet the head 18 can still be forced through ring 16 without damaging either part due to the tapered shape of head 18 and the slight stretchability of the materials, which are preferably of plastic.

According to another feature of the invention, at the end opposite from head 18, the inner wall of the valve stem around axial channel 17 is force-fitted in a recess 34, is pushbutton 8, which recess is in communication through conduit 35 with convergent portion 36 of the venturi nozzle in nozzle insert 9.

Channels 21 communicate through a conduit 38 in the pushbutton 8 with a second chamber 39 defined between the wall of cavity 11 and nozzle insert 9. Nozzle insert 9 has radial channels 41 therein extending between chamber 39 and the neck of the venturi in nozzle insert 9, which neck is followed by the divergent portion 42.

According to another feature of the invention, the propellant cartridge 43 is attached to a flange 44 around the bottom of support 2. In the embodiments illustrated, tightness is insured by a gasket 45 inserted between flange 44 and the bead under neck of cartridge 43. This gasket can also be cast in place or else it can be dispensed with if support 2 is made of some sufficiently flexible material (for example polyethylene) to permit a tight fastening of the collar of cartridge 43.

If the propellant cartridge 43 is made of plastic material, the collar can be sealed or glued directly onto support 2.

The resulting independent subassembly can be assembled by means of axial force fitting with a limited number of sealing or welding operations which, furthermore, can be done on known automatic machines.

With cartridge 43 in position on support 2, it is possible to create a vacuum inside it, and axial channel 17 of valve stem 7 will, once the latter has been inserted through gasket 15, make it possible to create a vacuum in said cartridge and to fill it with liquefied propellant gas 46 by means of conventional packaging machines. The subassembly is then ready for mounting on a container 47 (FIG. 2) containing a product 48 to be dispensed.

For this purpose, cover 1 has a rim 49 which fits over a recessed shoulder 51 on container 47. These two parts can be assembled by ultrasonic welding. Shoulder 51 and rim 49 can be proportioned in such a Way as to allow for the positioning of a movable cover 52 thereover, which cover caps pushbutton 8 during periods when it is not in use.

It will be understood that when pushbutton 8 is pressed down in the direction of arrow F, valve stem 7 slides in aperture 5 and valve cup 6 (FIG. 3). The shoulder on the wall of valve stem 7 above apertures 19 causes the inner edge of gasket 15 to bend downwardly. Apertures 19 are thus opened to the propellant cartridge 43 while gasket 15 remains tightly engaged around valve stem 7 above the apertures 19. The propellant in a gaseous state then escapes through channel 17 and reaches the convergent portion 36 of the venturi nozzle (arrows P) through conduit 35. Expansion of the propellant through the venturi in nozzle insert 9 creates a reduced pressure in chamber 39 which is transmitted by conduit 38 to annular channel 21 and to apertures 23 which are open into valve cup 6, the inner edge of gasket 4 having been bent downwardly by the shoulders above the said apertures 23, while still tightly closing off communication between valve cup 6 and the outside. The reduced pressure is communicated through valve cup 6 to dip tube 29, thus drawing the product 48 to be dispensed up the dip tube 29 through valve cup 6 and then through annular channel 21, up to radial channels 41 (arrows L) from Where it is sprayed out of the nozzle 9 by the action of the propellant.

At the same time, the pressure reduction created in product container 47 by the discharge of product 48 causes outside air to be drawn in through opening 5 5 around valve stem 7 and, since the edge of gasket 4 is bent downwardly between the latter and the annular projection 28; it then enters radial channel 32 and from there goes into the space above the product in container 47 (arrows A).

The dispenser thus has a simplified structure and a high pressure valve which integrates with support 2 and which is very reliable in its operation. The weight as well as the cost are reduced, and the parts can be assembled very rapidly.

The embodiment of FIGS. 4 and 5 differs from that of FIGS. 1-3 in that high pressure gasket 55 is a non-yielding tubular type and valve stem 7 has a cylindrical stud lower end portion with the head 18 on the end. A single aperture 57 can be provided in the lower end of the valve stem. At rest, aperture 57 is situated within the thickness of gasket 55 which closes it off.

In this embodiment, plug 24 has a downwardly opening annular groove 58 in which the upper end of the spring 25 fits. This makes is possible to increase the stroke of valve stem 7 as well as the amount of compression of spring 25 if necessary, or to have a more compact unit.

The embodiment of FIGS. 6 and 7 also has a thick annular high pressure gasket 58 forming the high pressure obturator similar to the gasket 55, but the retaining ring 59 for gasket 58 is located on the side of the gasket toward cartridge 43, said ring 58 being force-fitted in a seat 61 which communicates with diverging recess 13. This arrangement makes it possible to install a gasket 58 which has a larger outside diameter than the one which must be inserted through valve cup 6, which helps to make the joint more secure.

It will be noted that in this embodiment, channel 17 at its upper end opens into a chamber 62 having a large size, which chamber communicates with convergent portion 36 of nozzle 9, for reasons that will be explained later on.

A dispenser having a yielding type high pressure gasket 15 according to the first embodiment (FIGS. 1 to 3) and dispensers with thick

high pressure gaskets

55 or 58 and a sliding valve stem according to the other two embodiments (FIGS. 4 to 7) have different dynamic characteristics which make possible specific technical effects with each of these dispensers, so that one or another of these embodiments can be selected depending on the technical effect desired.

More precisely, assuming that a product 48 to be dispensed by the first embodiment is a liquid, when the valves are opened, flow of the propellant occurs before that of the liquid, and the reverse occurs when they are closed, as shown by the curve in FIG. 8 where there has been shown the rate of flow (for example in grams per second) at D and the stroke of atomizer 7 (for example 111 mm.) at H.

It should be understood that a difference in the degree to which pushbutton 8 is depressed by the user w ll cause the efiiciency of the system to vary, i.e. the ratio between the amount of propellant and of product that are discharged will vary.

The sequence of operations for one typical dispenser is as follows (FIG. 8):

(1) Depress from to 0.3 mm.nothing is discharged;

(2) Depressing from 0.3 to 0.6 mm.only the propellant is discharged up to its maximum rate of flow of 0.6 (or 0.120 gm./sec.);

(3) Depressing from 0.6 to l mm.only the propellant continues to be discharged (at a constant rate of 120 gm./sec.);

(4) Depressing from 1 to 1.6 mm.the propellant is still discharged at a maximum rate, and the product is aspirated at a rate which increases with the repression up to 1.6 mm. (from 0 to 0.360 gm./sec.);

Beyond 1.6 mm. the total maximum flow remains constant.

When the pushbutton is released and rises, the reverse sequence occurs. This has the advantage of completely expelling the liquid remaining in the nozzle. When the pushbutton is pressed down again, there is a fine spray from the beginning and there are no droplets discharged before the spray begins.

The only negative aspect of this advantage is that the user has to press down all the way on pushbutton 8; otherwise the efficiency of the dispenser is below its maximum value, in that the propellant is used up more quickly than the liquid to be dispensed and container 47 cannot always be emptied completely.

In the 2nd and 3rd embodiments, a variety of dynamic conditions can be obtained depending on the relative positions of the high and low pressure obturators with respect to the apertures in valve stem 7, and the thickness of the high pressure gasket.

In particular, according to one system, the propellant can flow after the low pressure valve has been opened. Then, for example, the following sequence occurs (FIG. 9):

( 1) Depressing from 0 to 1nothing is discharged;

(2) Depressing from 1 to 1.6-the passage for the liquid to be dispensed is open but nothing is discharged;

(3) Depressing from 1.6 to 1.7the liquid passage remains wide open but nothing is dispensed;

(4) Depressing from 1.7 to 2the liquid passage is open and the propellant gas passage opens gradually until a maximum total rate of flow of 0.480 gm./sec. occurs;

(5) Beyond 2 mm. the maximum total flow remains constant.

When the pushbutton is released and rises again, the reverse sequence occurs. Spraying stops as soon as the gas is shut off. Efficiency remains constant and container 47 containing the liquid to be dispensed is emptied completely.

Since under this arrangement resistance to depression of the pushbutton is practically constant, the danger of operating the dispenser at reduced efficiency is practically nonexistent.

This method of operation is the one that makes the most efficient use of propellant; on the other hand, since the liquid is drawn upwardly until the very last moment before the propellant is cut off, some liquid remains in the dispensed product passages after the dispenser is shut off, and this results in droplets being projected when spraying begins the next time.

According to another preferred system of operation of the invention for sliding type high pressure gaskets, provision is made for the arrangement of the apertures for the passage of propellant and liquid dispensed product in such a way that the propellant begins to be discharged a very short time before the liquid circuit is opened. In other words (FIG. 10) provision is made for an overlapping of the opening of propellant circuit G (stroke hi hg and liquid dispensed produce circuit L (stroke h h Under these conditions, the conduit containing the dispensed liquid is totally drained by the propellant at the end of the dispensing period and there is no danger of droplets at the start of the next spray operation.

Of course, in order to reduce the consumption of propellant, there is an advantage to reducing the length of stroke h' h as much as possible.

By another arrangement, which is more preferable than the one just described, the droplets can be eliminated 'while reducing still further the consumption of propellant.

Provision is made to open the propellant passages slightly after the dispensed product passages in the same way as in FIG. 9, and the two following conditions are observed:

For example the high pressure gasket 60 and aperture 57 in FIGS. 6 and 7 are positioned relative to each other in such a way that no appreciable pressure drop occurs during the passage of the propellant gas along channel 17 of valve stem 7. This result is achieved by giving to aperture 57 a significantly larger cross sectional area than that of the neck of the venturi nozzle in nozzle insert 9 (for example 2 to 8 times greater);

Providing for a sufficient volume of gas between the high pressure gasket and the venturi in nozzle insert 9; this is achieved by providing chamber 62 as shown in the embodiment in FIGS. 6 and 7.

More precisely, chamber 62 should have a capacity such that the time of discharge of the propellant gas under pressure contained in channel 17 and chamber 62 should be at least equal to the total time required for the valve stem to pass from the position where the propellant is shut off to that where the liquid flow is shut off, thus cleaning out the nozzle. This period is very brief, perhaps on the order of $4 of a second.

Of course, with the sliding type of high pressure gasket, provision is always made so that aperature 57 in the valve stem is closed by the gasket when the valve stem is in the undepressed condition, so as to prevent passage of the liquid contained in valve cup 6 into channel 17.

What is claimed is:

1. 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 accomodate a propellant cartridge within the product container, said plug valve assembly comprising a hollow valve stem, a pushbutton actuator on the upper end of said stem and having a nozzle therein communicating with said hol low 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 under side of said cap and having a hollow central interior through which said hollow stem is movable, a dip tube secured in said support and opening into said hollow interior, a fluid product flow path through said hollow stern 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, a second flexible gasket means in the bottom of said support through which said hollow stern passes, said hollow stem having an aperture therein opening into the hollow of the stern, said aperture being obturated by said second flexible gasket means, and means on said support to which a propellant cartridge can be secured in gas tight relationship to said support.

2. A plug valve assembly as claimed in claim 1 in which said first flexible gasket means is held between said support and the under side of said cap.

3. A plug valve assembly as claimed in claim 1 in which said hollow stem has a plurality of grooves along the outside surface thereof and an outer wall depending from said pushbutton actuator around said outside surface covering said longitudinal grooves, said longitudinal grooves forming part of said fluid product flow path.

4. A plug valve assembly as claimed in claim 1 in which said hollow interior of said support has a ring force-fitted into the bottom thereof, said second flexible gasket means being held between said ring and the bottom of said hollow interior.

5. A plug valve assembly as claimed in claim 1 in which said support has a downwardly open recess in the bottom thereof through which the lower end of said hollow stem extends, said second flexible gasket means being in the inner end of said recess, and a retaining ring force-fitted in said recess and holding said flexible gasket means in said recess.

'6. A plug valve assembly as claimed in claim 1 in which said hollow stem has a head on the lower end thereof and said support has an aperture in the end thereof remote from said cap through which said hollow stem extends and has retaining means holding said second flexible gasket means therein, said retaining means having an aperture therein through which the hollow stern extends, the outside diameter of said head being larger than the inside diameter of the aperture in said retaining means, whereby the stem is not forced through the retaining means by excess gas pressure from the end of said stem.

7. A plug valve assembly as claimed in claim 1 in which said hollow stem has a plug thereon within said hollow interior, said plug having an annular recess therein opening toward the end of said hollow stem remote from said pushbutton, and a spring around said hollow stem within said hollow interior and having one end in said recess and the other end engaged with the end of the hollow interior adjacent said second flexible gasket means.

8. A plug valve assembly as claimed in claim 1 in which the end of said hollow stern on which said pushbutton is positioned has an inner wall around the hollow of the stem extending beyond an outer wall enclosing a fluid product flow path extending along the exterior of said hollow stem, and said pushbutton has a recess therein into which the end of the hollow stem is fitted with the end of the interior wall against the bottom of the recess and an outer wall depending from said pushbutton and enclosing said stem, said stem having longitudinal grooves therein enclosed by said outer wall to define longitudinal passages, and said pushbutton having a first passageway therein from said longitudinal passages to the narrow portion of said nozzle for conducting fluid product to be dispensed from the stem to said nozzle, and having a second passageway from the center of said recess in communication with the hollow of said stem to said nozzle for conducting propellant gas to said nozzle from said hollow stem.

9. A plug valve assembly as claimed in claim 1 in which said pushbutton has a chamber therein between the end of said hollow stern and said nozzle in the propellant flow path, said chamber having a volume sufficiently large to accommodate enough propellant to evacuate the fluid product from the flow path therefor between the first flexible gasket means and said nozzle after aperture in said hollow stem is closed by said second flexible gasket means.

10. 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 within the product container, said plug valve assembly comprising a valve stem, a pushbutton actuator on the upper end of said stem and having a nozzle therein, a cap member adapted to fit over a product container and having an aperture therein through which the stem is movable, a support secured to the under side of said cap and having a hollow central interior through which said stem is movable, a dip tube secured in said support and opening into said hollow interior, a first flexible gasket means in said assembly through which said stem passes, a second flexible gasket means in the bottom of said support through which said stem passes, and means on said support to which a propellant cartridge can be secured in gas tight relationship to said support, said valve stem having a first stem end, and a second stem end thickened so as to form a shoulder with the adjacent wall of said stem member, said valve stem having an annular zone of constant diam eter adjacent said thickened stem end, said zone being engaged by said second flexible gasket means, said valve stem having shoulder means intermediate said annular zone and said first stem end adapted for engagement by said first flexible gasket means; said valve stem having first duct means therethrough extending in the axial direction thereof, which duct means has one open end in said first stem end, and having the other end opening in at least one orifice in said annular zone and obturated by said second flexible gasket means; and said valve stem having second duct means extending in the axial direction thereof and having one end opening in said first stem end and having the other end opening at said shoulder .and obturated by said first flexible gasket means; said pushbutton actuator having a recess in which said first stem end is inserted, and said nozzle comprising a venturi having a convergent portion, said pushbutton actuator having annular duct means having at least one radial aperture communicating with said venturi, and a propellant reverse chamber communicating with said convergent portion; said pushbutton actuator having propellant duct means therein, one open end of which propellant duct means communicates with the opening of said first duct means in said first stem end and the other open end of which communicates with said propellant reserve chamber, and said pushbutton actuator having fluid duct means therein, one end of which communicates with the open end of said second duct means in said first stem end, and the other end of which communicates with said annular duct means of said nozzle.

11. The plug valve assembly as claimed in claim 10-, wherein the shortest distance between said orifice and the adjacent shoulder formed by said thickened stem end is such that, upon movement of said pushbutton away from its non-dispensing position, said first flexible gasket means flexes to open the other end of said second duct means in said valve stem before said second flexible gasket means flexes to open the other end of said first duct means in said valve stem.

12. The plug valve assembly as claimed in claim 10 wherein the ratio of the total volume of said propellant reserve chamber plus the volume of said convergent nozzle portion plus the volume of said first duct means in said valve stem to the minimum diameter of the venturi of said nozzle is such that the discharge time of the gaseous propellant, which is contained in the total volume after closure of said second flexible gasket means, is at least equal to the total time required for said valve stem to pass from a propellant-closure position to fluid-closure position, plus the time necessary for clearing a fluid remaining in said annular duct means of said nozzle.

13. The plug valve assembly as claimed in claim 10 wherein said valve stem has on its outer surface a set of longitudinal ribs, and wherein said pushbutton has a socket in which said stem is inserted, and on the inner surface of which socket the said longitudinal ribs of said stem are supported in such a way as to form said second duct means for the passage of the fluid.

References Cited UNITED STATES PATENTS 3,326,469 6/1967 Abplanalp et a1. 222-193 X 3,131,834 5/1964 Meshberg 222399 STANLEY H. TOLLBERG, Primary Examiner.

US. Cl. X.R. 239-308