METERING VALVE WITH IMPROVED METERING CHAMBER

Abstract

Metering valve for dispensing a fluid product, having a valve body containing a metering chamber, the metering chamber defined by a chamber insert and two O-rings, a valve stem seal and a chamber seal. The chamber insert has a cylindrical wall, an upper edge that cooperates with the valve stem seal and a lower edge that cooperates with the chamber seal, a valve stem sliding axially in the valve body between a rest position and a dispensing position, to selectively dispense the contents of said metering chamber. The said valve stem is urged towards its rest position by a spring that cooperates, on the one hand, with the valve body and on the other hand with the valve stem. The upper edge of the chamber insert has an opening connecting the metering chamber to an external volume arranged outside the chamber insert, between the valve body and the cylindrical wall.

Claims

1. A metering valve for dispensing a fluid product, comprising a valve body containing a metering chamber, said metering chamber being defined by a chamber insert and two O-rings, a valve stem seal and a chamber seal, said chamber insert comprising a cylindrical wall, an upper edge that cooperates with said valve stem seal and a lower edge that cooperates with said chamber seal, a valve stem sliding axially in said valve body between a rest position and a dispensing position, to selectively dispense the contents of said metering chamber, said valve stem being urged towards its rest position by a spring that cooperates, on the one hand, with said valve body and on the other hand with said valve stem, characterised in that said upper edge of said chamber insert comprises an opening connecting said metering chamber to an external volume arranged outside said chamber insert, between said valve body and said cylindrical wall.

2. The metering valve according to claim 1, wherein said upper edge of said chamber insert extends radially inwards by a upper flange which increases the contact surface with said valve stem seal, said contact surface always being the same, whatever the width of said cylindrical wall.

3. The metering valve according to claim 1, wherein said lower edge of said chamber insert extends radially inwards by a lower flange which increases the contact surface with said chamber seal, said contact surface always being the same, whatever the width of said cylindrical wall.

4. The metering valve according to claim 1, wherein the volume of said metering chamber is modifiable between 25 and 100 l, without modification of said valve body, by adapting the thickness of said cylindrical wall and/or the number, shape and/or dimensions of said openings.

5. The metering valve according to claim 1, wherein said cylindrical wall of said chamber insert comprises a single opening.

6. The metering valve according to claim 1, wherein said cylindrical wall of said chamber insert comprises two diametrically opposed openings..

7. The metering valve according to claim 1, wherein said cylindrical wall of said chamber insert comprises a plurality of openings distributed over the periphery of said cylindrical wall.

8. Device-A device for dispensing a fluid product, characterised in that it comprises a metering valve according to claim 1, said valve being mounted on a reservoir containing the fluid product and a propellant.

9. The device according to the 8 claims, wherein said propellant comprises HFA gases, such as HFA a and/or HFA-227 and/or HFA-152a.

10. The device according to claim 8, wherein said propellant comprises HFO1234ze.

Description

[0018] FIG. 1 is a transverse, cross-sectional schematic view of a metering valve of the prior art, in the rest position of the valve, in the upright storage position of the valve,

[0019] FIG. 2 is a view similar to that of FIG. 1, showing a metering valve according to an advantageous embodiment of the invention, during an actuation of the valve shut-off element,

[0020] FIG. 3 is a detailed perspective view of a metering chamber insert of the prior art,

[0021] FIGS. 4 to 8 are detailed perspective views of different variant embodiments of said metering chamber insert according to the invention;

[0022] In the description below, the terms top, bottom, lower, upper and vertical refer to the upright position represented in FIGS. 1 and 2, and the terms axial and radial refer to the longitudinal central axis of the valve.

[0023] FIG. 1 represents a metering valve of the prior art at rest, in the upright storage position, i.e. the position in which the valve is arranged above the reservoir. FIG. 2 represents a metering valve in an advantageous embodiment of the invention, during actuation. It must be noted that the valve of FIG. 2 is also represented in the upright position, while the normal position of use of such a valve is an inverted position, with the valve arranged under the reservoir.

[0024] This valve is intended to be assembled on a reservoir (not shown) containing the fluid product and a propellant, preferably by means of a fixing element 5, which can be a crimpable, screw-fastenable, or snap-fastenable capsule, and advantageously with interposition of a neck seal 6. Possibly, a ring 4 can be assembled around the valve body 10, in particular to decrease the dead volume in the inverted position and so as to limit contact between the fluid product and the neck seal 6. This ring 4 can be of any shape, and the example of FIGS. 1 and 2 is not limiting. In general, the reservoir contains the fluid product and the propellant, in particular a formulation made up of one or more active principle(s) in suspension and/or in solution in a liquefied propellant, as well as possible excipients. The propellant preferably comprises one or more HFA gases, such as HFA-134a and/or HFA-227 and/or HFA-152a, with or without ethanol. In a variant, other non-harmful gases can be used, such as HFO1234ze.

[0025] The metering valve represented in FIGS. 1 and 2 comprises a valve body 10 extending along a longitudinal central axis and containing a metering chamber 20. This metering chamber 20 is defined between two O-rings, a valve stem seal 21 and a chamber seal 22, in a well-known manner. This metering chamber 20 is filled before or after each actuation with a dose of fluid product from the reservoir.

[0026] Inside said valve body 10, a valve stem 30 slides between a rest position, that is the position shown in the FIG. 1, and a dispensing position in which the valve stem 30 has been pushed into the valve body 10. The valve stem 30 is urged towards its rest position by a spring 8 that is arranged in the valve body 10 and that cooperates on the one hand with the valve body 10 and on the other hand with the valve stem 30, preferably with a radial collar 320 of the valve stem 30. The valve stem 30 slides inside said metering chamber 20 so as to enable its contents to be dispensed when the valve is actuated.

[0027] The valve body 10 includes a cylindrical portion 15 in which the spring 8 is arranged, and in which the collar 320 slides between its rest and dispensing positions. In the position of FIGS. 1 and 2, this cylindrical portion 15 is the lower portion of the valve body. This cylindrical portion 15 comprises one or more openings 11, such as slots, extending laterally in said cylindrical portion 15 of the valve body, over a portion of the axial height of the valve body in the direction of the longitudinal central axis. These openings make it possible to fill the metering chamber 20 after each actuation, when in the inverted position of use (with the valve arranged below the reservoir), when the valve 30 returns from its dispensing position to its rest position.

[0028] In known manner, the valve stem 30 may be made of two portions, namely an top portion 31 (also known as a valve-stem top) and a lower portion 32 (also known as a valve stem bottom).

[0029] The top portion 31 comprises a central axial channel 35 provided with an axial outlet orifice 301 and a radial inlet channel 302 which is arranged in the metering chamber 20 when the valve stem 30 is in its dispensing position. The top portion 31 also comprises a radial shoulder which, in the rest position represented in FIG. 1, bears under the valve stem seal 21, in a known manner.

[0030] In this embodiment, the lower portion 32 is assembled inside the top portion 31.

[0031] An internal channel 33 is provided in the valve stem 30, in particular in the bottom portion 32, that makes it possible to connect the metering chamber 20 to the reservoir 1, so as to fill said metering chamber 20 after each actuation of the valve when the valve stem 30 returns to its rest position under the effect of the spring 8. Filling is performed when the device is still in its upside down working position, with the valve arranged below the reservoir.

[0032] In the embodiment in FIG. 1, when the valve stem 30 is in its rest position, the metering chamber 20, outside the valve stem 30, is substantially isolated from the reservoir 1 by cooperation between the lower portion 32 of the valve stem 30 and the chamber gasket 22. In the rest position, the metering chamber 20 thus remains connected to the reservoir merely via said internal channel 33. The valve represented in FIGS. 1 and 2 is thus a retention valve. However, the invention is also applicable to other types of valves, in particular valves of the non-priming types.

[0033] The volume of the metering chamber 20 is defined by means of a chamber insert 40, of substantially cylindrical shape.

[0034] FIG. 3 illustrates the chamber insert of the prior art valve of FIG. 1, and FIGS. 4 to 8 show several different variants of a chamber insert according to the invention.

[0035] The chamber insert 40 comprises a cylindrical wall 49, the radial thickness of which is more or less large, depending on the desired volume of the metering chamber. Thus, it is mainly by acting on the thickness of this cylindrical wall 49 that the volume of the metering chamber 20 can be modified. In the prior art valve, this volume can vary between 25 and 75 l.

[0036] The valve stem seal 21 rests on the upper edge 41 of the chamber insert 40, and the chamber seal 22 is in contact with the lower edge 43 of the chamber insert 40. The upper edge 41 advantageously comprises a projecting profile 42 which penetrates in the valve stem seal 21, and the lower edge 43 advantageously comprises a projecting profile 44 which penetrates in the chamber seal 22.

[0037] Advantageously, the lower edge 43 extends radially inwards by a lower flange 46 which increases the contact surface with the chamber seal 22. In this advantageous variant, the lower edge 43 and said lower flange 46 together form a contact surface with the chamber seal 22 which is always identical, whatever the width of the cylindrical wall 49. The positioning of the chamber seal 22 on the chamber insert 40 is thus always identical, whatever the width of the cylindrical wall 49 and thus the volume of the metering chamber 20. Due to this, the behaviour of the chamber seal 22 will always be the same, whatever the volume of the metering chamber 20.

[0038] Advantageously, the upper edge 41 extends radially inwards by a upper flange 47 which increases the contact surface with the valve stem seal 21. In this advantageous variant, the upper edge 41 and said upper flange 46 together form a contact surface with the valve stem seal 21 which is always identical, whatever the width of the cylindrical wall 49. The positioning of the valve stem seal 21 on the chamber insert 40 is thus always identical, whatever the width of the cylindrical wall 49 and thus the volume of the metering chamber 20. Due to this, the behaviour of the valve stem seal 21 will always be the same, whatever the volume of the metering chamber 20.

[0039] With the prior art chamber insert 40 shown in FIGS. 1 and 3, the volume of the metering chamber 20 is defined exclusively within said chamber insert 40. Indeed, through the closed cylindrical wall 49 and the two seals 21 and 22, the external volume located outside the chamber insert 40, between the valve body 10 and the cylindrical wall 49, is totally isolated from the metering chamber. With a standard valve body as shown in FIG. 1, this external volume can represent up to about 5 l, which for a metering chamber volume of 25 to 75 l is not negligible. Even if it is not visible in FIG. 1, this external volume still exists between the valve body 10 and the cylindrical wall 49 of the chamber insert 40, because of the clearance necessary between these two parts to allow the insertion of the chamber insert 40 into the valve body 10.

[0040] According to the invention, the cylindrical wall 49 of the chamber insert 40 comprises at least one opening 48 connecting said metering chamber 20 to said external volume. Thus, the volume of the metering chamber 20 is increased, on the one hand, by the addition of said external volume and, on the other hand, by the volume represented by each opening 48 in the cylindrical wall 49. Thus, without modifications to the valve body 10, the metering chamber 20 with a chamber insert 40 according to the invention can have a volume greater than 75 l, for example 85 l. Volumes up to about 100 l are possible, depending on the number and dimensions of the openings 48 in the cylindrical wall 49.

[0041] Another advantage of the invention is that by including the external volume in the metering chamber, there is no longer any pressure difference between the inside and the outside of the cylindrical wall 49 of the chamber insert 40. In the example of the prior art in FIGS. 1 and 3, such a pressure difference could reach about 3 to 6 bar, depending on the nature of the propellant gas used, with a pressure in the external volume of 1 bar and a pressure in the metering chamber of 4 to 7 bar. This pressure difference may in some cases cause a deformation of the cylindrical wall 49 and thus an undesirable modification of the volume of the metering chamber 20.

[0042] FIGS. 4 to 8 show several different variants of a chamber insert 40 according to the invention.

[0043] In the example of FIG. 4, there is a single opening 48, advantageously cylindrical, which passes through the cylindrical wall 49 of the chamber insert, to connect the metering chamber 20 with the external volume existing between the valve body 10 and the cylindrical wall 49 of the chamber insert 40.

[0044] In the example of FIG. 6, there are two openings 48, which are diametrically opposed. In this example, the thickness of the cylindrical wall 49 is reduced, such that the upper 47 and lower 46 flanges also extend radially outwards from the cylindrical wall 49.

[0045] The example in FIG. 5 is similar to the example in FIG. 6, except that the chamber insert does not have an upper flange 47.

[0046] In the example in FIG. 7, there are a plurality of openings 48 formed by axial slots distributed around the periphery and extending over a portion of the height of the cylindrical wall 49 from the upper edge 41.

[0047] In the example in FIG. 8, there is a plurality of openings 48 formed by windows distributed around the periphery and extending over a portion of the height of the cylindrical wall 49 from the lower edge 43.

[0048] Naturally, in all the above examples, the number, shape and dimensions of each opening 48 can be any number, shape and dimension.

[0049] Although the present invention is described above with reference to particular embodiments thereof, naturally it is not limited by the examples shown. On the contrary, any useful modification could be applied thereto by a person skilled in the art, without going beyond the ambit of the present invention, as defined by the accompanying claims.