WO1999044890A1

WO1999044890A1 - Pressure regulating device for pressurised can

Info

Publication number: WO1999044890A1
Application number: PCT/AU1999/000117
Authority: WO
Inventors: Eugene Didenkowski
Original assignee: DINCO TRADING PTY Ltd
Current assignee: DINCO TRADING PTY Ltd
Priority date: 1998-03-03
Filing date: 1999-03-01
Publication date: 1999-09-10
Anticipated expiration: 2000-09-03
Also published as: AUPP211298A0

Abstract

A pressure regulating unit (4, 40, 80) for maintaining a constant gas or liquid pressure within a pressurised dispensing vessel (1), said unit comprising a sealed chamber (5) delimited by one or more sealed chamber walls (42, 46), a flow passage (13, 19, 20) communicating the sealed chamber (5) to the interior of the dispensing vessel (1), a first one-way valve (30) placed in the flow passage to normally allow flow only into said sealed chamber (5), said first one-way valve (30) including an actable override mechanism (12) for temporarily allowing flow along said passage from said sealed chamber to the interior of the vessel, and actuation means (8, 16) for causing the actuation of the override mechanism (12) when the pressure within the pressurised vessel is instantaneously reduced to below that within the sealed chamber.

Description

- 1 -

TITLE: PRESSURE REGULATING DEVICE FOR PRESSURISED CAN

The present invention relates to pressure regulating units and in particular to such units for maintaining a constant gas or liquid pressure within a pressurised dispensing vessel. The invention will be described with particular reference to use in the dispensing of an aerosol or spray from a closed container such as a can, but it is to be understood, however, that the invention is not limited to that application.

An aerosol or spray can generally comprises a vessel containing pressurised gas or liquid. A release valve and associated spray head are provided on top of the vessel and may be actuated by a user so that the gas or liquid flows through the release valve and the spray head and is dispensed in a desired direction.

The force and regularity of the gas or liquid stream dispensed from the aerosol can is dependent upon the pressure of the gas or liquid held within the pressurised dispensing vessel at any instant in time. As the gas or liquid is dispensed from the pressurised vessel by a user, the pressure of the gas or liquid remaining within the pressurised vessel reduces. As the pressure differential between the interior of the vessel and the exterior atmosphere becomes smaller, the force of the stream from the spray head reduces, eventually leading to an irregular or sputtering type of ejection from the spray head. Such irregular dispensing of gas or liquid is particularly inconvenient for the user of such an aerosol can.

In order to address this concern, pressure regulating units have been proposed for insertion into such aerosol cans. Such pressure regulating units seek to compensate the loss of pressure within the pressurised dispensing vessel resulting from the dispensing of the gas or liquid contained within, by releasing stored quantities of like gas or liquid into the dispensing vessel as the gas or liquid is dispensed from the spray head. To date, however, such pressure regulating units have been complex and unreliable, resulting in uncertain performance and difficulty of manufacture.

It is an object of the present invention to provide a pressure regulating unit for maintaining a constant gas or liquid pressure within a pressurised dispensing vessel which minimises or alleviates one or more of the aforementioned problems of prior pressure regulating units. It is a further object of the invention to provide such a pressure regulating unit which is of simple and reliable construction.

With this in mind, the present invention provides a pressure regulating unit for maintaining a constant gas or liquid pressure within a pressurised dispensing vessel, said unit comprising a sealed chamber delimited by one or more sealed chamber walls, a flow passage communicating the sealed chamber to the interior of the dispensing vessel, a first one-way valve placed in the flow passage to normally allow flow only into said sealed chamber, said first one-way valve including an actable override mechanism for temporarily allowing flow along said passage from said sealed chamber to the interior of the vessel, and actuation means for causing the actuation of the override mechanism when the pressure within the pressurised vessel is instantaneously reduced to below that within the sealed chamber.

Preferably, the actuation means acts to bear against and cause the actuation of the override mechanism when the pressure within the pressurised vessel is instantaneously reduced by the dispensing of the liquid or gas. In one embodiment, the actuation means includes an expandable pressurised chamber which expends when the pressure within the pressurised vessel is instantaneously reduced, the pressurised chamber being partly delimited by an actuator wall which is caused to bear against the override mechanism when the pressurised chamber expands. The actuator wall may be at least partially constituted by a resilient diaphragm. Conveniently, the first one-way valve comprises an aperture formed through a first one of said sealed chamber walls and forming part of the flow passage, a pin passing through the aperture and acting, in a first position, to seal the aperture and, in a second position, to communicate the sealed chamber to the interior of said vessel, and biasing means for biasing the pin into said first position. Preferably, the actuation means act to bear against the pin and place the pin in the second position to thus cause activation of the override mechanism.

The actuator wall may include retaining means for retaining one end of the pin. These retaining means may include a skirt at least partially surrounding, said one end of the pin. The first sealed chamber wall maybe constituted, at least in part, by a closure member acting to close the seal chamber. The aperture being formed through the closure member. The closure member and the remaining sealed chamber walls may be interconnected by means of cooperating threaded sections.

The expandable chamber may also be partly delimited by a cap member, the actuator wall being secured around its periphery to the inner surface of the cap member. The cap member may be attached to the sealed chamber walls by means of an annular skirt. In one embodiment of the invention, the annular skirt is formed separately from the cap member and may be sealed thereto by means of cooperating threaded sections. In another embodiment, the annular skirt may be integral with the cap member. The flow passage may include a first portion communicating the sealed chamber to a region delimited by the annular skirt and a second portion including one or more vent holes through the walls of the annular skirt. Conveniently, the expandable chamber may include a second one-way valve to normally allow flow only into the actuator chamber. The second one-way valve may be constituted by a membrane flat valve covering an aperture in the actuator wall.

The actuator wall may be secured around its periphery to the inner surface of the cap member by means of a pressure seal. The pressure seal may be provided by means of an O ring fitted around the periphery of the actuator wall. Alternatively, the pressure seal may be provided by a lip seal around the periphery of the actuator wall, the lip seal acting to allow flow only into the pressurised chamber past the periphery of the actuator wall.

The cap member may include one or more abutment members projecting towards the actuator wall for limiting movement of the actuator wall. The abutment members may act to prevent the actuator wall from disengaging the first one-way valve. The following description refers in more detail to the various features of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the pressure regulating unit is illustrated in a preferred embodiment. It is to be understood that the pressure regulating unit of the present invention is not limited to the preferred embodiment as illustrated in the drawings. In the drawings:

Figure 1 is a cross sectional side elevation of an aerosol can including a first embodiment of a pressure regulating unit according to the present invention;

Figure 2 is a cross sectional enlarged side view of the pressure regulating unit shown in Figure 1; Figure 3 is a detailed view of a one way valve in the actuator chamber of the pressure regulating unit of Figure 2;

Figure 4 is a detailed view of the annual skirt and cap member of the pressure regulating unit of Figure 2;

Figure 5 is a detailed view of the interconnection between the annular skirt and sealed chamber of the pressure regulating unit of Figure 2;

Figure 6 is a detailed view of the one way valve, stem and diaphragm of the pressure regulating unit of Figure 2;

Figure 7 is a cross-sectional side elevation of a second embodiment of a pressure regulating unit according to the present invention; - 4 -

Figures 8 and 9 are detailed views of the one-way valve and cap member of the pressure regulating unit of Figure 7;

Figure 10 is a detailed view of a second one-way valve in the actuator chamber of the pressure regulating unit of Figure 7; Figure 11 is a cross-sectional side elevation showing the mounting of the pressure regulating unit of Figure 7 in an aerosol can;

Figure 12 is a cross sectional side elevation of a third embodiment of a pressure regulator unit according to the present invention; and

Figure 13 is a detailed view of the lip seal between the actuator wall and cap member of the pressure regulating unit of Figure 12.

Turning now to Figure 1, there is shown a pressurised dispensing vessel 1, such as an aerosol can, which contains pressurised gas or liquid. This latter is dispersed from within the pressurised dispensing vessel via an outlet valve 2 and a spray head 3. In use, when a user presses on the upper surface of the spray head 3, the spray head is caused to bear against and actuate the outlet valve 2 and thus enable gas or liquid from within the pressurised dispensing vessel 1 to flow along the outlet valve 2 and out the spray head 3. The pressurised dispensing vessel 1, may contain, by way of example, fly repellant, paint, or even beverages such as wine.

Housed within the pressurised dispensing vessel 1 is a pressure regulating unit 4. The pressure regulating unit 4 may be freely moveable within the interior of the pressurised dispensing vessel, or alternatively may be mounted in fixed interrelation with one or more of the interior walls of the pressurised dispensing vessel, either directly or via one or more ribs (not shown) extending between the vessel wall and the exterior of the pressure regulating unit 4. As best seen in figure 2, the pressure regulating unit 4 includes a sealed chamber

5, a closure member 6, an annular skirt 7 and a cap member 8. The closure member 6 is connected to the walls of the sealed chamber 5 by means of cooperating threaded sections 9 and 10 respectively formed in the exterior surface of the wall of the sealed chamber 5 and the interior surface of the closure member 6. In other embodiments, various other arrangements may be used to interconnect the closure member and the sealed chamber.

In addition, an annular seal 11 is provided in the wall of the sealed chamber 5. The seal 11 engages the surface of the closure member 6 and acts against unwanted leakage of any pressurised gas or liquid from within the sealed chamber to the interior of the pressurised vessel via the join between the wall of the sealed chamber and the closure - 5 - member 6. In other embodiments, the seal 11 may be provided on the surface of the closure member, or may be separately made and inserted between the wall of the sealed chamber and the closure member. Figure 5 provides a more detailed view of the interconnection of the sealed chamber and the closure member. The pressure regulating unit 4 also includes a one-way valve 30 comprising a pin

12 passing through an aperture 13 provided through the closure member 6. The pin 12 acts, in a first position, to seal the aperture and, in a second position, to communicate from the sealed chamber 5 to the interior of the pressurised dispensing vessel 1. Biasing means are provided to normally bias the pin into the first position. Accordingly, the one-way valve 30 normally allows the flow from the exterior of the closure member into the sealed chamber 5, whilst preventing flow in the opposite direction. The one-way valve 30 is of the type which includes an actuable override mechanism for allowing the pin to be maintained in the second position and to thereby allow flow from the interior of the sealed chamber 5 to the exterior of the closure member 6. Such valves and override mechanisms are well known and will not be described in detail, but may conveniently be of the type whereby the override device is caused to be actuated by the application of a downward pressure on the pin 12. Such device is common for example, are frequently used in conjunction with bicycle tyre valves.

The pressure regulating unit 4 may also include a diaphragm or membrane 16 which, together with the cap member 8, forms, in this embodiment, actuation means for causing the actuation of the override device of the one way valve 12. The diaphragm 16 forms one wall of an actuator chamber which is intended to expand, the flexible diaphragm being caused to indirectly bear against the override mechanism of the one way valve 12 via the stem 14. As best seen in Figure 4, the diaphragm 16 may be secured between the cap member 8 and the annular skirt 7. Conveniently, the cap member 8 and the annular skirt 7 may be interconnected by means of cooperating threaded sections 17 and 18 formed respectively on facing surfaces of the cap member 8 and the annular skirt 7.

The annular skirt also acts to attach the actuator chamber, formed by the cap member and the diaphragm 16, to the sealed chamber 5 and closure member 6.

One or more apertures 19, 20 may be provided through the annular skirt 7 in order to provide communication from the area within the pressure regulating unit delimited by the annular skirt and the exterior of the pressure regulating unit 4. In order to maintain the diaphragm and stem in secure interrelation, the exterior surface of the diaphragm 16 may include retaining means 21, 22 for retaining one end of the stem 14. In this example, the retaining means may be constituted by a skirt which at least partially surrounds one end of the stem. As can be seen from Figure 3, the cap member 8 may include one or more apertures 23 communicating the actuator chamber delimited by the cap member 8 and the diaphragm 16, with the interior of the pressurised dispensing vessel 1. In addition, a membrane 24 may be provided which covers the aperture 23 on the interior surface of the cap member 8, thus forming a membrane one way valve which enables air to flow into the expandable chamber, but acts against air flowing out from the confines of the expandable chamber.

Upon the dispensing vessel 1 being pressurised, gas or liquid is introduced into the interior of the dispensing vessel. This pressurising gas or liquid fills the interior of the dispensing vessel and enters the pressure regulating unit through the apertures 19, 20. This pressurised gas or liquid flows through the membrane valve 23 into the interior of the expandable chamber constituted by the cap member 8 and the diaphragm 16. The pressure differential between the area delimited by the annular skirt 7 and the interior of the pressurised chamber 5 causes the pin 12 in the one-way valve 13 to be depressed and thus allow the flow of the pressurised gas or liquid into the pressurised chamber 5. This continues until there is negligible pressure differential between the interior of the pressurised chamber 5 and the exterior of the pressure regulating unit 4.

The pressurised dispensing vessel is then sealed and fitted with the outlet valve 2 and the spray head 3, so that the interior of the pressurised dispensing vessel, including the sealed chamber 5 and other spaces and reservoirs or chambers within the pressure regulating unit are all at an equal pressure.

Upon dispensing of the gas or liquid from the pressurised dispensing vessel 1 , there will be an immediate reduction in the pressure in the dispensing vessel 1 to the exterior of the pressure regulating unit 4. Accordingly, a pressure differential will exist between the interior of the actuator chamber 8, 16, which will be instantaneously held at the former high pressure within the dispensing vessel 1, and the exterior of the pressure regulating unit, which will now be at a lower reduced pressure. This pressure differential will result in the expansion of the actuator chamber, and the consequent movement of the diaphragm 16 towards the stem 14. This downward movement exerts a force on the stem 14 which causes the operation of the override mechanism in the one way valve 12. Gas or - 7 - liquid held within the sealed chamber 5, which is maintained at a higher pressure than the remaining gas or liquid in the dispensing vessel 1, is forced through the one way valve 12, along the interior of the hollow stem 14 and out of the aperture 25 in the side wall of the hollow stem 14. The gas or liquid is then forced from the pressure regulating unit 4 through the apertures 19, 20 formed in the annular skirt 7.

Upon cessation of the dispensing of the gas or liquid from within the dispensing vessel 1, the gas or liquid from the interior of the sealed chamber 5 continues to be forced from the pressure regulating unit 4 until a pressure equilibrium is established between the gas or liquid within the sealed chamber 5 and the gas or liquid to the exterior of the pressure regulating unit but within the dispensing vessel 1. The diaphragm 16 will then return to its original position, as shown in Figure 2, and cease to exert a force on the stem 14 which causes the override mechanism to be activated. In this way, the pressure regulating unit is self regulating to the desired can pressure.

Figure 7 shows a second embodiment of a pressure regulating unit according to the present invention. This figure shows a pressure regulating unit 40 including, as described previously, a sealed chamber 41 delimited by one or more sealed chamber walls 42, 43 a flow passage communicating the sealed chamber 41 to the interior of the dispensing vessel 1, a first one-way valve 44 placed in the flow passage to normally allow flow only into the sealed chamber. The one-way valve 44 includes an actuable override mechanism for temporarily allowing flow along the passage from the sealed chamber 41 to the interior of the vessel, an actuation means 45 for causing the actuation of the override mechanism when the pressure within the pressurised vessel is instantaneously reduced to below that within the sealed chamber.

As is the case in the embodiment of the pressure regulating unit 4 shown in Figures 1 to 6, one of the sealed chamber walls is constituted at least in part by a closure member 46 acting to close the sealed chamber 41. In this example, the closure member 46 and the remaining sealed chamber walls 42 are interconnected by means of cooperating threaded sections 47, 48.

Similarly, the one-way valve 44 comprises an aperture 49, (as can be best seen in Figures 8 and 9) formed through the closure member 46 and forming part of the flow passage communicating this sealed chamber to the interior of the dispensing vessel. A pin 50 is provided which passes through the aperture 49 and which acts, in a first position (Figure 8) to seal the aperture 49 and, in a second position (Figure 9) to communicate the sealed chamber 41 to the interior of the pressurised dispensing vessel 1. In this example, - 8 - the pin 50 is provided with a head 51 and cooperating O ring 52 for ensuring a tight seal of the aperture when the pin 50 is in the first position shown in Figure 8. Biasing means 53 —in this case a spring - are provided between the actuation means 45 and the exterior surface of the closure member 46 in order to bias the pin into the first position sealing the aperture. In this example, the actuation means 45 includes an expandable pressurised chamber 54 which expands when the pressure within the pressurised vessel 1 is instantaneously reduced. The pressurised chamber 54 is partly delimited by an actuator wall 55 which is caused to bear against one end of the pin 50 when the pressurised chamber 54 expands. As was the case in the previously described embodiment, the actuator wall is in this case at least partially constituted by a resilient diaphragm.

The actuator wall 55 is provided with retaining means for retaining a first end 56 of the pin 50. In this example, the retaining means include a skirt 57, 58 at least partially surrounding one end of the pin.

As can be best seen in Figure 10, the expandable chamber 54 is also delimited by a cap member 59. The actuator wall 55 is secured around its periphery to the inner surface 60 of the cap member 59. The cap member 59 is attached to the sealed chamber walls 42, 46 by means of an annular skirt 61. Unlike the embodiment of the pressure regulating unit illustrated in Figures 1 to 6 though, which showed an annular skirt formed separately from and subsequently attached to the cap member, in this embodiment the annular skirt 61 is integral with the cap member 59. The actuator wall may be secured around its periphery to the inner surface of the cap member 59 by means of a pressure seal. As seen in Figure 10, the pressure seal may be provided by means of an O ring 62 fitted around the periphery of the actuator wall 55.

As was the case with the pressure regulating unit 4, the expandable chamber 54 includes a second one-way valve 63 to normally allow flow only into the actuator chamber. The second one-way valve 63 may be constituted by a membrane flap valve in the actuator wall 55.

As can be best seen in Figures 8 and 9, the cap member 59 includes two abutment members 64 and 65 projecting from the upper surface of the cap towards the actuator wall 55. These abutment members act to limit the movement of the actuator wall in the direction of the longitudinal axis of the pin 50. Accordingly, the abutment members act to prevent the diaphragm 55 from moving to an extent such that the annular skirt 57, 58 disengages from the pin 50. In addition, the abutment members 64, 65 acts to retain the pressure seal between the actuator wall 55 and the cap member 59 by limiting the shearing force which may otherwise cause the periphery of the actuator wall to slide with respect to the inner surface of the cap member 59.

As explained previously, the pressure regulating unit 40 may either be freely movable within the interior of the pressure dispensing vehicle or alternatively may be mounted in fixed interrelation with one or more of the interior walls of the pressure dispensing vessel. Figure 11 shows one such example of a mounting arrangement in which ribs 70, 71 and 72 extend between the interior wall 73 of this pressure dispensing vessel and the sealed chamber wall 42.

Figures 12 and 13 show a further embodiment of a pressure regulating unit according to the present invention. These figures show a pressure dispensing unit 80 comprising the sealed chamber 41 delimited by the sealed chamber walls 42 and closure member 46, the cap member 59 and annular skirt 61, and one-way valve 44 illustrated in the pressure regulating unit 40 shown in Figures 7 to 11. In this embodiment of the invention, however, the pressure seal between the periphery of the actuator wall 55 and the inner surface 60 of the cap member 59 is provided by a lip seal 81. The Hp seal 81 is provided around the periphery of the actuator wall 55 and acts to allow flow only into the pressurised chamber around the periphery of the actuator wall 55, as indicated by the arrows 82, 83. Accordingly, when the pressure regulating unit 80 is initially pressurised, gas or liquid is able to enter through the venting hole 84 and then pass around the periphery of the actuator wall into the pressurised chamber 55. However, once the chamber 54 is pressurised, the lip 85 is forced against the inner surface 60 of the cap member 59 so as to prevent the gas or liquid contained therein from escaping.

Those skilled in the art will appreciate that there may be many variations and modifications of the configuration described herein which are within the scope of the present invention.

Claims

- 10 -CLAIMS

1. A pressure regulating unit for maintaining a constant gas or liquid pressure within a pressurised dispensing vessel, said unit comprising: a sealed chamber delimited by one or more sealed chamber walls, a flow passage communicating the sealed chamber to the interior of the dispensing vessel; a first one-way valve placed in the flow passage to normally allow flow only into said sealed chamber, said first one-way valve including an actuable override mechanism for temporarily allowing flow along said passage from said sealed chamber to the interior of said vessel, and actuation means for causing the actuation of the override mechanism when the pressure within the pressurised vessel is instantaneously reduced to below that within the sealed chamber.

2. A pressure regulating unit according to claim 1, wherein the actuation means act to bear against and cause the actuation of the override mechanism when the pressure within the pressurised vessel is instantaneously reduced by the dispensing of the liquid or gas.

3. A pressure regulating unit according to claim 2, wherein the actuation means includes an expandable pressurised chamber which expands when the pressure within the pressurised vessel is instantaneously reduced, the pressurised chamber being partly delimited by an actuator wall which is caused to bear against the override mechanism when the pressurised chamber expands.

4. A pressure regulating unit according to claim 3, wherein said actuator wall is at least partially constituted by a resilient diaphragm.

5. A pressure regulating unit according to any one of claims 1 to 4, wherein the first one-way valve comprises; an aperture formed through a first one of said sealed chamber walls and forming part of the flow passage; a pin passing through the aperture and acting, in a first position, to seal the aperture and, in a second position, to communicate said sealed chamber to the interior of said vessel, and - 11 - biasing means for biasing the pin into said first position.

6. A pressure regulating unit according to claim 5, wherein the actuation means acts to bear against the pin and place the pin in said second position to thus cause activation of the override mechanism.

7. A pressure regulating unit according to claim 6, wherein the actuator wall includes retaining means for retaining one end of the pin.

8. A pressure regulating unit according to claim 7, wherein the retaining means includes a skirt at least partially surrounding the one end of the pin.

9. A pressure regulating unit according to any one of claims 5 to 8, wherein said first sealed chamber wall is constituted at least in part by a closure member acting to close the sealed chamber, the aperture being formed through the closure member.

10. A pressure regulating unit according to claim 9, wherein the closure member and the remaining sealed chamber walls are interconnected by means of cooperating threaded sections.

11. A pressure regulating unit according to any one of the preceding claims, wherein the expandable chamber is partly delimited by a cap member, the actuator wall being secured around its periphery to the inner surface of the cap member.

12. A pressure regulating unit according to claim 11, whereby the cap member is attached to the sealed chamber walls by means of an annular skirt.

13. A pressure regulating unit according to claim 12, wherein the annular skirt is integral with the cap member.

14. A pressure regulating unit according to either of claim 12 or 13, wherein the flow passage includes a first portion communicating the sealed chamber to a region dlimited by the annular skirt, and a second portion including one or more vent holes through the walls of the annular skirt.

15. A pressure regulating unit according to any one of the preceding claims, wherein the expandable chamber includes a second one-way valve to normally allow flow only into the actuator chamber. - 12 -

16. A pressure regulating unit according to any one of the preceding claims, wherein the second one-way valve is a membrane flap valve in the actuator wall.

17. A pressure regulating unit according to any one of claims 11 to 16, wherein the actuator wall is secured around its periphery to the inner surface of the cap member by means of a pressure seal.

18. A pressure regulating unit according to claim 17, wherein the pressure seal is provided by means of an O ring fitted around the periphery of the actuator wall.

19. A pressure regulating unit according to claim 17, wherein the pressure seal is provided by a lip seal around the periphery of the actuator wall, the lip seal acting to allow flow only into the pressurised chamber past the periphery of the actuator wall.

20. A pressure regulating unit according to any one of the preceding claims, wherein the cap member includes one or more abutment members for limiting movement of the actuator wall.

21. A pressure regulating unit according to claim 20, whereby the abutment members act to prevent the actuator wall from disengaging the first one-way valve.