US3664548A

US3664548A - Aerosol containers and valves thereof

Info

Publication number: US3664548A
Application number: US53591A
Authority: US
Inventors: Rory Wilson Broderick
Original assignee: NORMAN JOHN THOMPSON; Institue for Industrial Research and Standards
Current assignee: NORMAN JOHN THOMPSON; Institue for Industrial Research and Standards
Priority date: 1969-07-10
Filing date: 1970-07-09
Publication date: 1972-05-23
Anticipated expiration: 1989-05-23
Also published as: CH523179A; CA931118A; ES192970U; AT306624B; ES192970Y; GB1291918A

Abstract

THE DISCLOSURE ILLUSTRATES A VALVE WHICH MAY BE USED FOR THE AUTOMATIC OR MANUAL ACTUATION OF A DISPENSER FOR PRESSURIZED FLUIDS. THE VALVE INCORPORATES A PERMEABLE MEMBRANE, FOR EXAMPLE A LOW DENSITY POLYETHYLENE FILM, WHICH ALLOWS VAPOR FROM THE DISPENSER TO PERMEATE INTO THE VALVE AND GIVE RISE TO A PRESSURE BUILD-UP UNDER A SEALED DIAPHRAGM. THE PRESSURE BILD-UP EVENTUALLY CAUSES THE DIPHRAGM TO RELEASE A SPRING MECHANISM TO ACTUATE THE SPRAY OR AEROSOL DISCHARGE. ONCE DISCHARGE IS COMPLETE THE VAPOR UNDER THE DIAPHRAGM IS DISCHARGED AND THE MECHANISM AUTOMATICALLY RESET TO START THE CYCLE AGAIN.

Description

May 23, 1972 R. w. BRODERICK AEROSOL CONTAINERS AND VALVES THEREOF m S or a .3 Fl/ 04/ 8? Wm G i 2 m 4 0 J 6 i M N "III 0 7 \\N w 9, w M u J d 9 1 m y 23, 1972 R. w. BRODERICK 3,664,548

AEROSOL CONTAINERS AND VALVES THEREOF Filed July 9, 1970 r 5 Sheets-Sheet 3 lnvenlar Kw! wefionmu By I AGE/VT May 23, 1972 R. w. BRODERICK AEROSOL CONTAINERS AND VALVES THEREOF L5 Shoctu-l311eut 41 Filed July 9, 1970 mam Eur

lnoenlor R RY W. BRUDERICR v 6 a 6 4 ml 3 5 0 r 1/ 5 Z 8 4. 0/ 2 m m B A May 23, 1972 R. w. BRODERICK AEROSOL CONTAINERS AND VALVES THEREOF Filed July 9, 1970 IZE/I 56 United States Patent Oflice" 3,664,548 Patented May 23, 1972 3,664,548 AEROSOL CONTAINERS AND VALVES THEREOF Rory Wilson Broderick, Dalkey, Ireland, assignor to Institute for Industrial Research and Standards, and Norman John Thompson, both of Dublin, Ireland Filed July 9, 1970, Ser. No. 53,591

Claims priority, application Ireland, July 10, 1969,

941/69 Int. Cl. B67d 5 08 U.S. Cl. 22261 .24 Claims ABSTRACT OF THE DISCLOSURE The disclosure illustrates a valve which may be used for the automatic or manual actuation of a dispenser for pressurised fluids. The valve incorporates a permeable membrane, for example a low density polyethylene film, which allows vapour from the dispenser to permeate into the valve and give rise to a pressure build-up under a sealed diaphragm. The pressure build-up eventually causes the diaphragm to release a spring mechanism to actuate the spray or aerosol discharge. Once discharge is complete the vapour under the diaphragm is discharged and the mechanism automatically reset to start the cycle again.

The present invention relates to aerosol containers and particularly to valves for use in said containers. The term aerosol containers is intended to refer to enclosed containers charged with a fluid under pressure that is adapted to be expelled from the container by the pressure therein or more briefly a dispenser for pressurised fluids; A Conventional aerosol containers are normally provided with a valve operable by finger pressure to open the valve and thereby enable fluid in the container to issue to atmosphere. A demand exists, however, for aerosol contermittently operating the valve to permit periodic emission of fluid from the aerosol container.

With a view to avoiding the expense involved in providing mechanically or electro-mechanically operable means for dispensing fluid from aerosol containers, a primary object of the present invention is to provide, for use in such a dispenser for pressurised fluids, a valve which is manually operable and which is operable automatically to dispense at regular intervals of time, a quantity of fluid from the dispenser. 1

According to the invention, there is provided a valve for a dispenser for pressurised fluids, said valve comprising a valve housing incorporating a permeable membrane and pressure responsive means, the permeable membrane which allows vapour under pressure in the dispenser to penetrate into the valve housing to build-up pressure in the valve housing, the said built-up pressure actuating the pressure responsive means in the valve housing to open the valve, to discharge through thevalve, pressurised fluid from the dispenser.

. Advantageously, the permeable membrane'which enables vapour to enter the valve housing from the interior of the dispenser, permits a build-up of pressurein the valve housing over a time period substantially in excess means serves to open the valve to enable a quantity of fluid to discharge from the dispenser. The process of penetrationof vapour through the permeable membrane is generally thought to be a solution or absorption of vapour on the surface of the membrane followed by diffusion of the vapour through the membrane. The vapour penetration rate is approximately inversely related to the thickness of membrane used and also approximately linearily related to the pressure difference across the membrane. Thus for example the time period of the automatic cycle may readily be controlled by merely varying the thickness of membrane used.

In a preferred construction according to the invention, the valve comprises:

(a) A bottom enclosure adapted to hold in sealed engagement a permeable membrane and to house a sealing cup within a metering chamber which is connected by a dip tube to the pressurised fluid in the dispenser.

(b) A mounting cup adapted at one end for fluid tight mounting on the dispenser the other end of the mounting cup engaging the bottom enclosure, housing a capillary stem seated, at one end thereof, in the sealing cup and pressure responsive means (c) An actuator which projects to atmosphere from the mounting cup and contains a spray button with an orifice open to atmosphere, the orifice being connected to the capillary stem at that end thereof remote from the metering chamber.

The pressure responsive means utilised may to advantage comprise a flexible diaphragm mounted above a core, a cradle member, a snap spring mounted on the cradle member, a collar fixedly mounted on the capillary stem and a cradle return spring, whereby a build-up of pressure due to the pressurised vapour penetrating into the valve housing causes the flexible diaphragm to move away from thecore above which his mounted and force the cradle to move in the same axial direction, until the snap spring isactuatedto depress the collar and hence the capillary stem and the sealing cup to open the valve to dispense the pressurisjed fiuid in the metering chamber to. atmosphere and allow dischargeof the pressurised fluid which has penetrated into the valve housing to atmosphere. I

Preferably the permeable membrane is a polyethylene film, though ethylene vinyl acetate film, polytetrafluorethylene and fluorosilicone rubber have also-been found to be most suitable.

The invention will be more clearly understood from the following description of preferred embodiments of the invention given by way of example only with reference to the accompanying drawings in which FIG. 1 isan elevation in section of a valve in the closed position thereof, with the valve set for automatic operation FIG. 2 is an elevation similar to FIG. 1 but showing the valve in the open or spray discharge position FIG. 3 is a plan view of the valve FIG. 4 is an elevation similar to FIG. 1 showing the valve in a closed position and set for manual actuation FIG. 5 is an elevation in section of a modified construction of valve, the valve beingvshown in the closed position 'and set for automatic operation.

of the time period during which the pressure responsive Referring to FIGS. 1-4 of the drawings, the constructionof the valve is described for the sake of clarity from its lower end, in its normal position of use, as shown in the drawings.

A-membrane sealing cap 10 having vertical slits in its sides 'to allow the sides to-fiex during the assembly operation, is snap fitted on to the bottom enclosure 11. The sealing cap 10 compresses a pair of O ring rubber seals 12 whichseal the periphery of a permeable membrane 13,

for example a low density polyethylene film, located .between the sealing cap and the bottom enclosure 11. A channel 11a, allows the pressurised vapour in the dispenser access to the permeable membrane 13. A disc of porous paper 14 lies between the permeable membrane 13 and the bottom of the bottom enclosure 11. A clip tube 15 is push fitted into an opening 16 in the side of the bottom enclosure 11 and the opening 16 communicates via a bore 17 and via an inlet port 21, with a metering chamber 18 within the bottom enclosure 11. The metering chamber 18 is provided with a spring loaded sealing cup 19 which normally engages under the action of spring a rubber seal 20 positioned at the top of the metering chamber 18. The bore 17 from the dip tube 15 to this metering chamber 18 terminates in the bottom of the metering chamber 18 in the inlet port 21 which is provided with a raised ridge 22. This ridge 22 allows a rubber ferrule seal 23 on the sealing cup 19 to seal olf this inlet port 21 when the sealing cup 19 is pressed downwards against it.

A plastic core 26 is located in the bottom enclosure 11, above the metering chamber 18. The core 26 is held in the bottom enclosure 11 by screw threads 27 or alternatively, it may be ultrasonically welded into place. With either assembly method, the core 26 compresses the periphery of the rubber seal 20 above the metering chamber 18 and ensures that the rubber seal 20 prevents the leakage of fluid (vapour or liquid) from the metering chamber 18 into a timing chamber 28, which is substantiallyfilled by the plastic core 26, and is beneath a flexible rubber diaphragm 29. An annular valve seat 30 projects down from a recess provided in the bottom face of the core 26. The rubber seal 20 above the metering chamber 18 is normally pressed against this seat by an upwards spring influenced thrust of the sealing cup 19 in the metering chamber 18. During the automatic cycle of the valve, the pressure of the contents of the metering chamber 18 also press the rubber seal 20 against this valve seat 30, as the pressure in the metering chamber 18 is the same as the dispenser contents pressure (except when the chamber is emptied and the valve is resetting) and the pressure above the rubber seal 20 is considerably lower.

The flexible rubber diaphragm 29 is fastened above the top of the core 26 by a hollow rivet 31. The rivet 31 passes through a hole in the centre of the diaphragm 29 and is a tight fit in a hole in the core 26. The head 31a of the rivet 31 compresses a bead 32, which is around the edge of the hole in the diaphragm29 against a ridge 33 formed in the core 26 and thereby creates a permanent seal here. The outer edge of the diaphragm 29 also contains a thickened bead 34 and this bead is compressed against a ledge 35 in a valve mounting cup 36, by a raised edge 37 on the top of the bottom enclosure 11. The bottom edge 39 of the valve mounting cup 36, a deep drawn metal component, is crimped in during assembly, under a step 38 in the outside wall of the bottom enclosure 11, to hold the bottom enclosure 11 in this position. This creates a permanent seal at the peripheral edge of the diaphragm 29 which serves two purposes, namely:

(a) To prevent the container contents fromleaking upwards past the ledge in the valve mounting cup and (b) To contain vapour, which has permeated into the,

space under the diaphragm.

From the foregoing, it may be seen that the timingchamber 28 is normally sealed from the atmosphere and also always sealed from the dispenser contents, except for the slow permeation of vapour through the membrane 13.

Within this timing chamber 28 vapour flow paths or channels are provided on the bottom and sides of the core 26 to ensure that permeated vapour, rising through a vertical hole 40 from the membrane 13, may readily flow to the timing chamber 28 which is on the underside of the diaphragm 29. These channels also allow the flow of this vapour to the core recess 26a where the annular valve seat 30 is located. 1

A hollow capillary stem 41 extends from the top of the valve, down through the pressure responsive means and the timing chamber 28 into the metering chamber 18.,A spray button 42 is located on the top of this stem 41 and the spray button 42 is provided with an exit orifice 43 for the discharge spray. The stem 41 is free to slide in the parts through which it runs and the bottom of the stern rests in a well 19a provided with an orifice groove 45, in the sealing cup 19. A collar 46, which is a tight fit, is located around portion of the stem 41.

In the top half of the valve mounting cup 36 above the diaphragm 29 there is located a pressure responsive mechanism. The pressure responsive means consists of a snap spring 48, a cradle 49, a cradle ring 50, a helical return spring 51, an automatic-manual actuator 53 and a cover 54. The snap spring 48 is a flat strip of spring steel which bows up when inserted into the cradle 49. The cradle contains locating slots to orient the snap spring 48 and the slots 55 are tapered to allow flexing of the ends of the snap spring 48. The slots 55 run around portion of opposite sides of the cradle 49 and are slightly wider than the snap spring 48. The narrowest part of the slots 55 open to the outside wall of the cradle 49 and thus ensure that the end-thrust of the snap spring 48 is taken by a steel cradle ring 50 which is pressed over the cradle 49. The bottom of the cradle 49 rests on the diaphragm 29 and it is pressed against the diaphragm 29 by the helical return spring 51. Two opposite portions of the bottom coil of this return spring 51 rest on two opposite ledges 56 formed on the inside face of the cradle 49.

The top of the helical return spring 51 presses the automatic-manual actuator 53 upwards against the cover 54 of the valve. Two raised ribs 57 are provided on the face of the actuator 53 which is close to the top inside face of the valve cover 54. When the actuator is in the automatic position, these ribs rest in two shallow grooves 58 provided in the top inside face of the valve cover 54. When the actuator 53 is in the manual position, the raised ribs 57 nest inside two slots 59 provided in the top of the valve cover 54. The slots 59 are shown in the plan view of the valve FIG. 3. The rotation of the actuator 53 from the automatic to the manual position thus has the eflect of retracting upwards by a predetermined amount, a finger 60 which has projected downwards from the actuator 56 into close proximity with the centre of the snap spring 48 for automatic operation of the valve.

The sides of the valve mounting cup 36 are crimped in at 61 to hold the valve cover 54 in place. The bottom edge 62 of the valve cover 54 acts as a cradle stop to limit upwards movement of the cradle 49. I

The valve may be operated manually by finger tip pres sure to give either:

(l) A continuous spray which is obtained by exerting slight finger pressure on the spray button or (2) A metered spray which is obtained by exerting a greater finger pressure on the spray button.

Both of these modes of manual spraying may be obtained with the automatic-manual actuator set in either the automatic or manual position. Detailed working is as follows:

(1) Continuous spray-Downward movement of the spray button 42 causes the capillary stem 41 to push the sealing cup 19 away from the rubber seal 20, against which the sealing cup 19 has been pressed by the action of the spring 25. The seal formed between the lip on the top of the sealing cup 19 and the rubber seal 20 is thus opened and this allows the product propellant mixture to flow from the metering chamber 18 into the well 1901 in the sealing cup 19 and from there, via the orifice groove 45 in the well 190, into the capillary stem 41 to emanate as a spray from the spray button orifice 43. If no further downward motion of the spray button 42 takes place, there will be a continuous flow of fluid into the metering chamber 18 from the dip tube 15, to maintain it full, so,

long as some pressurised contents remain in the disis applied initially to the spray button 42 and this causes the sealing cup 19 to open as before but also ensures that the ferrule seal 23 closes off the inlet port 21 into Automatic operation FIG. 1 shows the valve parts in their position at the start of the automatic cycle. The bottom enclosure 11 of the valve, which houses the permeable membrane 13 may be below the liquid level of the product/propellant mixture in the dispenser if the container is relatively full, or alternatively if the dispenser contents have been partially used, the membrane 13 may be above the liquid level and in the vapour phase alone. The liquid level in the dispenser dose not alfect the functioning of the valve. It may be assumed that the vapour pressure under the diaphragm 29, atvthe commencement of the-cycleis at atmospheric. The pressure of the propellant in the dispenser is above atmospheric pressure and typically will be about 4 to atmospheres. Because of this pressure difference, propellant vapour, from either the liquid or vapour phase, gradually permeates through the permeable membrane 13. The porous paper backing 14 under the membrane 13 allows sideways transmission of this vapour to the vertical hole 40 in the bottom enclosure 11 which communicates with the timing chamber 28 under the diaphragm 29. The timing chamber 28 is partially occupied by the core 26 and since the timing chamber 28 is sealed from the atmosphere, the pressure will gradually rise in the chamber 28 with a consequent extension upwards of the diaphragm 29. This causes the cradle 49 to move gradually upwards against the restrainingaction of the return spring 51 and the snap spring 48. The finger 60 projecting down from the automatic-manual actuator 53 limits the upward movement of the centre of the snap spring 48. When the edges of the snap spring 48, held in the cradle 49, reach a point level with or slightly above the bottom of the finger 60 the snap spring 48 snaps over-centre. As the bottom edge 62 of .the cover 54 acts as a cradle stop further upward movement of the cradle 49 is only possible to a marginal extenL Thus the snap spring 48 reacts downwards on the collar 46 of the capillary stem 41 and depresses the capillarystem 41 and sealing cup 19.

FIG. 2 shows the position of the valve parts during this discharge portion of the automatic cycle;- -As the inlet port 21 in the bottom of the metering chamber 18 has been closed by the ferrule seal 23, the product/propellant mixture, isolated in the meteringchamber' 18, will issue as a spray from the spraybutton orifice 43.

The emptying of the metering chamber 18 causes a resultant drop in pressure in it. The propellant'vapour under the diaphragm 29 is in communication with the core recess 26a above the'rubber seal 20 which is above the metering chamber 18 The resultant pressure dilference across this seal ,29 causes it to deflect downwards slightly into the metering chamber 18 and thereby move away from the annular valve seat 30 in the core'26. The deformation of this seal 20, as shown in FIG. 2, allows the vapour, trapped under the diaphragm 29 to escape to atmosphere. Its path in doing so follows a small channelv the capillary stem "41 and the holes of the parts throughwhich'the' stem slides. The cradle 49, presseddown by the return spring 5, forces the diaphragm 29 to deflate and expel the vapour. As the cradle 49 moves down during this deflation of the diaphragm 29, the snap spring 48 reacts against the collar 46 on the capillary stem 41 which forcesthe snap spring 48 to subsequently snap back .over centre? into its original position. This allows the sealing 'cup 19 to move up in the metering chamber 18 again to its original position of sealing against the rubber seal 20 above metering chamber 18. The automatic cycle will now commence again.

The automatic-manual actuator 53 projects upwards through the cover 54 of the valve and partially surrounds the spray button 42. An opening 47 in the side of the actuator 53 provides clearance for the spray from the exit orifice 43 of the spray button 42. The spray button 42 projects above the top of the actuator 53 to allow finger pressure to be applied to the button 42 for manual spraymg.

As previously mentioned a finger 60 projects down into the valve from the actuator 53 and this finger 60, in the automatic mode of the valve, serves to compress the snap spring 48 during upward movement of the cradle 49, and thus causes the snap spring 48 to snap over to the down position. Retraction upwards of the actuator 53 and finger '60 to the position shown in FIG. 4 switches the valve from the automatic to the manual mode. Upwards movement of the cradle 49 with the actuator 53 in this position does not now impose compression on the snap spring 48 and hence it will remain in the up position.

From the users point of view, the valve is switched from the automatic to the manual mode as follows: A metered spray is first dispensed by manual pressure on the spray button 42. The auto-manual actuator 53 is then grasped between the fingers, pressed down slightly and rotated a quarter turn to the manual position where it is released as it clicks into position. The same procedure is followed to revert to the automatic position.

The. initial manual spraying of a metered burst is necessary before turning the auto-manual actuator 53 as this serves to reset the cradle 49 to the position it normally has at the start of the automatic cycle. In this position the snap spring 48 is not reacting against the finger 60.of the actuator 53 .and the upwards force of the cradle return spring. 51 against the actuator 53 is at a minimum. Thus the actuator 53 can be easily depressed 1 y and rotated.

The switching of the actuator 53 from the automatic to-the manual position does not immediately stop penetration of vapour through the permeable membrane 13. Penetration of vapour continues for some time and will cease only when'the vapour pressure under the disphragm 29 hasreached equilibrium with the pressure in the dispenser. FIG. 4 shows thevalve in this manual position and this would normally be the position of the parts during storage of the dispenser (aerosol container) prior- 1 to sale or use.

A second embodiment of the invention is illustrated in- FIG. 5 of the accompanying drawings. In FIG. 5 like valve parts to those shown in FIGS. 1-4 illustrating the first embodiment, are given the same reference numeral, proceeded by the digit one, for the sake of clarity. In

this second embodiment the permeable membrane geometry has been altered and the form of the cradle return spring varied. The valve operates however in substantially the same manner as described in relation to the first embodiment.

The disc type of permeable membrane as illustrated in FIGS. 1, 2 and 4 of the accompanying drawings must be limited in area, if the valve is to fit into the standard one lIlCh opening of dispensers for pressurised fluids (aerosols). Accordingly, in applications of the valve where a fairly frequent intermittent spray is required, a different geometry of permeable membrane may be adopted to allow a larger effective area of permeable membrane for vapour penetration. The cylindrical type of permeable membrane shown in FIG. covers this requirement. Here the cylindrical permeable membrane 113, in the form of a length of tubular low density polyethylene film, is heat shrunk or slipped as a tight fit over the exterior surface of the bottom enclosure 111. If the bottom enclosure 111 has been manufactured from a compatible plastic material, the two ends of the cylindrical permeable membrane 113 may be heat sealed or bonded with an adhesive to the exterior cylindrical surface of this bottom enclosure 111 to form hermetic joints in these areas. A sleeve of porous paper 114 is interposed between the cylindrical permeable membrane 113 and the bottom enclosure 111, except in the area at the ends where the sealing takes place. This sleeve of. porous paper 114 lies in a shallow groove formed on the exterior cylindrical surface of the bottom closure 111. The porous paper 114 allows transmission of vapour, which has penetrated through the membrane 113, to a hole which communicates with the timing chamber 128.

With this form of construction, a very large area of permeable membrane 113 can be obtained readily. It also allows the more conventional bottom entry of the dip tube 115 into the valve.

FIG. 5 also illustrates an alternative geometry for the cradle return spring 151. Here a stack of disc springs have been substituted for the helical spring shown in the FIGS. 1, 2 and 4 of the accompanying drawings. These disc springs 151 may be full discs or alternatively may have radial cut outs so that each disc has a number of fingers projecting either radially inwards from a solid periphery or radially outwards from the centre portion of the disc. The springs 151 may be manufactured from conventional spring materials such as stainless steel or spring steel or alternatively may be manufactured from a bimetal spring material.

In some applications of the valve, the use of a bimetal material here may be necessary, in order to reduce the variation in frequency with temperature of the automatic intermittent operation. The pressure in a dispenser container normally increases with a rise in the ambient temperature, because of the properties of the propellant fluid. This results in a more rapid penetration of vapour through the membrane 113 and, with the valve construction shown previously, a faster automatic cycle. This m'ay be an advantage in both insecticidal and air freshe'ning applications, where higher temperatures normally result in more insects or more odours. In other applications, however, such as the automatic lubrication of machinery, a dispensing frequency which is relatively independent of ambient temperature may be required. In such an application, the disc springs 151 may be made of bimetal spring material, so arranged that the thrust of the springs 151 against the snap spring cradle 149 increases with temperature. A higher pressure under the diaphragm 129 is thus required to operate the valve and this, compensating for the higher pressure in the can, results in a relatively uniform automatic dispensing frequency.

What we claim is:

1. A valve for a dispenser for pressurized fluid, said valve comprising a valve housing incorporating a permeable membrane, a timing chamber in communication with the permeable membrane, pressure responsive means, an exit orifice, a fluid supply under pressure, and

a valve disposed intermittent the exit orifice and fluid supply, said permeable membrane allowing vapor under pressure in the dispenser to penetrate by diffusion into the valve housing along one path to build-up pressure in the timing chamber, said timing chamber being enclosed at least 'in part by a flexible diaphragm which can move in response to the build-up of pressure to actuate the pressure responsive means to open the valve and discharge fluid under pressure through a second path by way of the valve and exit orifice.

2. The valve of claim 1 wherein the pressure responsive means includes a snap spring which in response to 8 the build-up of pressure in the timing chamber can snap over from a first position to a second position to open the valve.

3. The valve of claim 1 includes a metering chamber within said second path, a closable inlet thereto in communication with the interior of the dispenser, a closable outlet therefrom in communication with atmosphere, and means for holding said inlet closed while said outlet is open, and vice versa. V

4. The valve of claim 1 wherein there is included:

(a) a bottom enclosure adapted to hold in sealed engagement the permeable membrane and to house a sealing cup within a metering chamber which is connected by a dip tube to the pressurized fluid in the dispenser;-

(b) a mounting cup adapted at one end for fluid tight mounting on the dispenser, the other end of the mounting cup engaging the bottom enclosure '(a), housing a capillary stem seated, at one end thereof, in the sealing cup and pressure responsive means; and

'(c) an actuator which projects to atmosphere from the mounting cup and contains a spray button with the orifice exit to the atmosphere, the orifice exit being connected to the capillary stem at that end thereof remote from the metering chamber.

5. A valve for a dispenser for pressurized fluids, said valve comprising:

(a) a bottom enclosure adapted to hold in sealed engagement a permeable membrane and to house a sealing cup within a metering chamber which is connected by a dip tube to the pressurized fluid in the dispenser;

(b) a seal member located between the sealing cup and the core, said seal member in co-operation with the sealing cup and the core being adapted to prevent vapor passing along the exterior and/ or interior of the capillary stem between the metering chamber and atmosphere and along the exterior of the capillary stem between the timing chamber and atmosphere when the valve is closed, the said sealmember being adapted to deform following discharge of the contents of the metering chamber to allow the vapor in the timing chamber, which has built up a pressure under the flexible diaphragm, to discharge to atmosphere, closing of the valve serving to allow the seal member reverse to its undeformed sealing position;

(c) a mounting cup adapted at one end for fluid tight mounting on the dispenser, the other' end of the mounting cup engaging the bottom enclosure, housing a capillary stem seated, at one end thereof, in

, the sealing cup and pressure responsive means; and

(d) an actuator which projectsto atmosphere from the mounting cup and contains a spray button with an orifice open to atmosphere, the orifice being connected .to the capillary stem at that end thereof remote from the metering chamber.

6. A valve as claimed in claim 3 which includes means 0 responsive to the evacuation of pressurised fluid from the metering chamber for releasing the pressure in the' timingvchamber and means responsive to the release of pressure from the timing chamber for closing the valve:

7. A valve as claimed in claim 6 wherein the means for closing the valve serve to close the outlet from the meable membrane is fiurosilicon rubber.

12. A valve as claimed in claim in which the bottom enclosure is provided with a membrane sealing cap which is snap fitted to the bottom enclosure to compress sealing members to seal in position a permeable membrane mounted upon the bottom enclosure, the membrane sealing cap having a channel therein to provide an access for the pressurised vapour in the dispenser to the permeable membrane.

13. A valve as claimed in claim 5 in which the permeable membrane is mounted upon a portion of the exterior surface of the bottom enclosure and heat sealed at its edges to the bottom enclosure.

14. A valve as claimed in claim 12 in which a layer of porous paper is provided between the permeable membrane and the bottom enclosure, the bottom enclosure having a communicating passage therein to allow the pressurised vapour penetrating the permeable membrane to pass to a timing chamber immediately adjacent a flexible diaphragm on a core side thereof.

15. A valve as claimed in claim 5 in which the bottom enclosure is provided with a metering chamber which houses a spring mounted sealing cup, the bottom of the metering chamber being provided with an inlet port connected to the dip tube, the sealing cup having mounted thereon a seal member which closes the inlet port when the sealing cup is depressed upon the opening of the valve.

16. A valve as claimed in claim 5 in which the sealing cup is provided with a well having an orifice groove which communicates with the end of the capillary stem within the well for discharge to atmosphere of the contents of the metering chamber when the valve is open.

17. A valve -for a dispenser for pressurised fluids as claimed in claim 5 in which the pressure responsive means comprises a flexible diaphragm mounted above the core, a cradle member, a snap spring mounted on the cradle member, a collar fixedly mounted on the capillary stem and a cradle return spring, whereby a build-up of pressure due to the pressurised vapour penetrating into the valve housing causes the flexible diaphragm to move away from the core above which it is mounted and "force the cradle to move in the same axial direction, until the snap spring is actuated to depress the collar and hence the capillary stem and the sealing cup to open the valve to dispense the pressurised fluid in the metering chamber to atmosphere and allow discharge of the pressurised 10 vapour which has penetrated into the valve housing to atmosphere.

18. A valve as claimed in claim 17 in which the flexible diaphragm is of rubber and is sealed on the bottom enclosure at its outer edge portions by the mounting cup and at its centre by a rivet mounted about the capillary stem.

19. A valve as claimed in claim 17 in which the snap spring of the pressure responsive means is a strip spring which bows when mounted in locating slots provided in the cradle said slots being adapted to locate and accommodate the end edge portions of the snap spring and to allow complete flexin g of the snap spring.

20. A valve as claimed in claim 17 in which the cradle of the pressure responsive means is provided with a cradle ring to provide a suitable bearing surface for the end edges of the snap spring.

21. A valve as claimed in claim 17 in which the cradle return spring is a helical spring mounted around the capillary stem and between the cradle and the actuator.

22. A valve as claimed in claim 17 in which the cradle return spring is a stack of disc springs of bimetal material responsive to a variation in temperature.

23.'A valve as claimed in claim 17 in which the actuator is provided with a finger which embraces the capillary stem and which is constrained for limited axial movement relative to the capillary stem for setting of the valve for automatic or manual operation, the flnger almost abutting against the snap spring when the valve is set for automatic operation and in an axially retracted position from the snap spring when the valve is set for manual operation.

24. A valve as claimed in claim 23 in which the actuator is provided with a cover fixedly mounted on the mounting cup and adapted to co-operate, by means of a complimentary rib and groove arrangement, with the actuator for setting of the valve for automatic or manual operation.

References Cited UNITED STATES PATENTS 3,115,277 12/1963 Montague, 1a., 222- UX 3,497,108 2/ 1970 Mason 222-499 ROBERT B. REEVES, Primary Examiner J. M. SLATIERY, Assistant Examiner