EP1216195B1 - Valve joint for metering valve - Google Patents

Description

The present invention relates to an improved valve seal for metering valve and a fluid dispensing device comprising a metering valve provided with a such improved valve seal.

The valves are well known in the state of the art. They find their main application with aerosol containers for fluid dispensing charged with a propellant (gas dissolved under pressure). When dosing, the valves generally comprise a valve body enclosing a delimited metering chamber axially by two annular seals, a valve seal and a chamber seal, and a movable valve stem between a rest position and an actuating position. This valve stem is urged by a spring towards its rest position, in which a shoulder of said rod is supported on the lower surface of said valve seal. For actuate the metering valve, press the valve stem that slides in the body of valve inside the annular seals to its actuating position, in which a dose of the product is expelled. This spring then brings the valve stem back into its rest position. Metering valves of this type are described in particular in EP-0 551 782, EP-0 350 376, FR-2 615 172, FR-2 615 173 and FR-2 615 124.

A problem that arises with the valve stems of valves, particularly metering valves, particularly concerns the sealing at the valve seal. On the one On the other hand, the valve stem must be able to slide between its actuating position and its resting position under the effect of the spring, while preventing leaks from occurring. On the other hand, it is necessary that in the rest position of the valve stem, the sealing is despite the pressure inside the dosing chamber and the container.

To solve these problems, the known valves generally comprise a rod cylindrical valve having an extension of said shoulder, at least on the portion of the valve stem that slides in the valve seal, a constant outside diameter about equal (usually very slightly higher) to the outside diameter of the opening center of the valve seal. To guarantee the tightness in the rest position, it is generally provided a frustoconical portion adjacent said shoulder and which extends axially on a portion of the thickness of said valve seal. So, the valve stem sliding with friction in the valve seal, the force exerted by the spring being greater than said friction, and, in its rest position, the frustoconical portion adjacent to said shoulder contributes to the seal at the valve seal.

A disadvantage of this implementation lies in the fact that the friction which appear when sliding the valve stem can be relatively important, which can cause a blockage of said valve stem. (phenomenon of sticking of the stem). In addition, the friction may deform the edge of the valve seal in contact with the valve stem, so that product can be introduced between said rod and said seal. Especially in the case of powdery product, this can hinder or even prevent the operation of the metering valve.

This phenomenon is further amplified when, in particular for ecological reasons, it is desired to replace environmentally harmful propellants such as CFCs, by propellants that are not or less harmful to the environment, such as by example HFA gases. However, the use of such little or no harmful significant increase in pressure inside the valve body, this increase up to 50%. It is therefore necessary to achieve a further seal higher at the valve seal, which implies a higher friction between the valve stem and said seal.

One possible solution to overcome this drawback is to provide a spring having a sufficiently high stiffness. This, however, requires an important force for operate the metering valve, which is undesirable.

Another solution is to coat the valve stems with a layer of silicone to improve its friction qualities. This solution is relatively satisfactory with propellants such as CFCs, but is not sufficient when HFA gases are used. Indeed, these HFA gases expel as the silicone, so that after a number of use, the problem of blockage of the valve stem reappeared.

An object of the invention is to provide a valve seal for a metering valve made of such as to prevent inadvertent blockage of the valve stem by friction on the seal when said valve stem moves relative to said valve seal, while sealing at said valve seal during this movement.

Another object of the invention is to provide a valve seal made in such a way that the valve stem operates reliably and safely with a low stiffness spring, thus facilitating its actuation.

Yet another object of the invention is to provide a metering valve operating with a propellant gas that is not harmful to the environment, said valve comprising a rod of valve can slide in the valve seal without leakage and without risk of blockage between its actuating position and its rest position under the effect of the spring.

The subject of the invention is therefore a valve seal for a metering valve intended to distributing a pulverulent product dispersed in a propellant, said metering valve having a valve body defining a dosing chamber, a valve stem sliding in said metering chamber between a rest position and a position the sealing between said valve stem and said dosing chamber being made by said valve seal, said valve body being fixed in a capsule of fastener for joining the valve to a product reservoir, said valve seal having a radially inner contact zone on which said rod of valve, said contact zone being fixed to a rigid element so that during the displacement of said valve stem, said contact area of the valve seal remains substantially fixed in shape and in position, said contact zone having a profile at less partially rounded, to reduce the contact area between said seal valve and said valve stem, said rigid member being a part, in particular the edge internal radial, of said fixing capsule. Thus, at equal dimensions of the stem of valve, it slides with less friction, which avoids the appearance of the blockage of the valve stem, while ensuring a perfect seal.

The use of such a valve seal therefore avoids any deformation of the seal valve, thus preventing entrapment of the product between the rod and the seal.

Advantageously, said valve seal is fixed, in particular snapped, on the edge radial interior of said attachment capsule.

Alternatively, said valve seal is directly molded on said radial edge inside said fixing cap.

The present invention also relates to a metering valve comprising such a seal of valve and a fluid dispenser device comprising such a valve dosing.

• la figure 1 est une vue schématique en coupe d'un joint de soupape,
• la figure 2 est une vue schématique en coupe d'un joint de soupape selon un mode de réalisation de l'invention,
• la figure 3 est une vue schématique en coupe d'une valve doseuse selon un mode de réalisation avantageux de la présente invention incorporant le joint de soupape de la figure 2, la tige de soupape étant dans sa position de repos, et
• la figure 4 est une vue similaire à celle de la figure 3, la tige de soupape étant dans sa position d'actionnement.

Other features and advantages will become apparent from the following detailed description of the invention, given by way of non-limiting example, with reference to the accompanying drawings, in which:

• FIG. 1 is a diagrammatic sectional view of a valve seal,
• FIG. 2 is a diagrammatic sectional view of a valve seal according to one embodiment of the invention,
• FIG. 3 is a schematic sectional view of a metering valve according to an advantageous embodiment of the present invention incorporating the valve seal of FIG. 2, the valve stem being in its rest position, and
• Figure 4 is a view similar to that of Figure 3, the valve stem being in its actuated position.

The invention will be described with reference to an example of a metering valve shown on the drawings, but it is clear that it applies to metering valves of all types.

With reference to FIGS. 3 and 4, a metering valve may comprise a valve body 1 containing a metering chamber 2. This metering chamber 2 may be delimited axially by two annular seals, a valve seal 3 and a chamber seal 4. These two joints may each have a central opening through which passes a valve stem 10, movable inside the valve body 1 between a rest position, shown in FIG. 3, and an actuating position, represented in FIG. valve stem 10 can be biased towards its rest position by an elastic member such as that a spring 5, bearing on the one hand on the bottom of the valve body 1 and secondly on the lower end of the valve stem.

The valve body 1 can be fixed, for example crimped, in a capsule 100 which comes then attach, for example by crimping, to the neck of any container or vial (not shown) Advantageously, a neck seal 101 is provided between said capsule 100 and said container neck.

The valve stem 10 generally comprises a distribution channel 12 opening through a radial hole 13 at its outer surface. In the rest position of the valve stem, said radial hole 13 opens out of the valve seal 3, while in said actuating position, it opens into the interior of the metering chamber 2.

The valve stem 10 may further comprise a radial shoulder 11 which is supported on the lower surface of the valve seal 3 in the rest position of the stem of valve 10, and which thus defines said rest position by acting as stop member against the thrust of the spring 5.

The valve stem 10 advantageously also comprises a conduit 14 which, in the rest position of the valve stem, connects a reservoir or container of product (not shown) with the metering chamber 2 to fill the latter, then that in the actuating position of the valve stem, it does not open into the dosing chamber 2.

The operation of this metering valve is conventional. The user exercises a pressure on the valve stem 10 which has the effect of moving it against the force of the spring 5 out of its rest position. As soon as this displacement starts, the conduit 14 more opens in the metering chamber 2 and it is then hermetically closed by the valve stem 10 at the chamber seal 4 and the valve seal 3. When the valve stem 10 reaches its actuating position, the radial hole 13 of the stem of valve opens into the dosing chamber 2, thus allowing the dispensing of the dose of product contained in said metering chamber via the 12. The user then releases his pressure on the valve stem 10 which is brought back by the spring 5 in its rest position where the conduit 14 opens into the dosing chamber 2, to fill it with a new dose of product.

The valve seal 3 has a radially internal contact zone 31 on which the valve stem 10 slides sealingly. According to the invention, this zone of contact 31 is attached to a rigid member 50 so as to substantially prevent any displacement and / or deformation of said contact zone 31 during the displacement of the rod valve 10.

With reference to FIG. 1, said rigid element 50 is a rigid insert disposed at the inside of said valve seal 3. Thus, the flexible part of the seal forming the contact zone 31 is retained axially by the rigid insert during the displacement of the valve stem 10, thus preventing product from entering between these two elements. The rigid insert 50 can for example be made of stainless steel, the seal being injected around said element.

According to an embodiment of the present invention shown in Figures 2 to 4, said rigid element is part of or integral with the fixing cap 100. In particular, the valve seal 3 is fixed around the inner radial edge 50 of said capsule. The area contact 31 of the seal 3 is held axially by said radial edge of the capsule. The seal 3 may be injection molded with a shape as shown in Figure 2, and then attached to the capsule 100, for example by snapping, or the seal 3 can be directly molded on the capsule 100.

Advantageously, the contact zone 31 of the valve seal 3 may further have at least partially rounded shape, to reduce the contact area between the seal and the valve stem, and thus reduce friction. Likewise, this form rounded also prevents product trapping at the ends of said contact area 31.

The valve stem 10 sliding better on the seal, its dimensions The outer parts may therefore be provided in such a way that it co-operates with the joint for ensure a perfect seal, even when using non-harmful gases such as HFA, while ensuring perfect sliding in the central opening of said seal, avoiding thus the problems of locking the rod.

The stiffness of the spring 5 to be directly proportional to the forces of friction exerted by the valve seal 3, the invention therefore makes it possible to use a spring having a lower stiffness. The actuation of the metering valve according to the invention is therefore facilitated in that the force necessary to actuate it is decreased.

Another advantage of the valve seal of the invention is that because of the decreased frictional forces exerted by the valve seal 3 on the rod of when the valve returns to its rest position, the speed of movement of the said valve stem is higher, which increases the reliability of the valve.

The invention thus guarantees a reliable operation of the metering valve and a total sealing at the valve seal, which allows in particular the use of propellants that are not harmful to the environment, such as HFA the significant increase in pressure inside the dosing chamber. Moreover, the use of a lower spring stiffness is made possible, which facilitates the actuation of the metering valve.

The invention has been described with reference to the figures which represent a metering valve operating in the upright position, but it obviously also applies to metering valves operating in the inverted position.

Claims (5)

1. A valve gasket for a metering valve serving to dispense a fluid, in particular a powder dispersed in a propellant gas, said metering valve comprising a valve body (1) defining a metering chamber (2), and a valve rod (10) mounted to slide in said metering chamber (2) between a rest position and an actuating position, the sealing between said valve rod (10) and said metering chamber (2) being provided by said valve gasket (3), said valve body (1) being fixed in a fixing cap (100) serving to assemble the valve onto a fluid reservoir, said valve gasket (3) being characterized in that it is provided with a radially inside contact zone (31) over which said valve rod (10) slides, said contact zone (31) being fixed to a rigid element (50) so that, while said valve rod (10) is moving, said contact zone (31) of the valve gasket (3) remains substantially unchanging in terms of its shape and of its position, said contact zone (31) having a profile that is rounded at least in part, so as to reduce the area of contact between said valve gasket (3) and said valve rod (10), said rigid element (50) being an integral part of said fixing cap (100), and in particular the inside radial edge thereof.
2. A valve gasket according to claim 1, in which said valve gasket (3) is fixed, in particular snap-fastened, to the inside radial edge (50) of said fixing cap (100).
3. A valve gasket according to claim 1, in which said valve gasket (3) is molded directly over said inside radial edge (50) of said fixing cap (100).
4. A metering valve, characterized in that it includes a valve gasket according to any one of claims 1 to 3.
5. A dispenser device for dispensing a fluid, in particular a pharmaceutical, said dispenser device being
   characterized in that it includes a metering valve according to claim 4.

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