EP3765385A1

EP3765385A1 - Flow reducer for a pressurized product dispenser

Info

Publication number: EP3765385A1
Application number: EP19709460.0A
Authority: EP
Inventors: Bernard BOREL; Hervé BODET
Original assignee: Lindal France SAS
Current assignee: Lindal France SAS
Priority date: 2018-03-11
Filing date: 2019-03-05
Publication date: 2021-01-20
Also published as: US11214431B2; FR3078762B1; WO2019174970A1; US20210107727A1; BR112020018405A2; FR3078762A1; AR114677A1; CA3089451A1; MX2020009373A

Abstract

The invention relates to a flow reducer (10) for a pressurized product dispenser of the type provided with a valve (30) equipped with a stem (20) having at least a first channel, and with a diffuser. According to the invention, the flow reducer (10) is a part separate from the stem and from the diffuser and comprises - a recess open on one side via an opening and able to be fitted by the opening over the stem (20) of a valve (30), - one or more first outlet orifices (134) which, when the reducer is mounted on the stem (20) of a valve, are able to be connected in a sealed manner to the first channel of the stem (20) of the valve while forming an extension (133) of the first channel, the outer face of the reducer, on the side opposite to the opening of the recess, having in part a contour substantially identical to that of the part of the stem (20) projecting from the valve that is intended to be covered by the reducer.

Description

Flow reducer for a pressure product dispenser

The invention relates to a flow restrictor for a pressurized product dispenser, in particular for an aerosol generator of the type equipped with a diffuser and a valve equipped with a stem.

Pressure product dispensers are commonly used in many fields. To distribute their contents, they are equipped with valves equipped with a stem. Depending on requirements, these may be single-lane valves or two-way valves. Two-way valves are used when two products must be kept separately until they are applied simultaneously. For this, the products are stored in two different tanks, usually two pockets side by side or one in the other, or one in a pocket and the other in the housing of the aerosol. The two-way valves can also be used to dispense the product contained in the distributor by a first route and the propellant through the other way, the product possibly being contained in a bag protected from the propellant gas. To operate the valve, a diffuser is placed at the top of the stem. When the diffuser is used with a two-way valve, the two products come into contact only at the outlet of the stem, or even at the outlet of the diffuser. To introduce the product or products in the pressure product dispensers, it is common to enter their tanks (bags or housings) respectively via the valve, so via the pathways through the stem. This operation is all the easier and faster as the products are not very viscous and the channels have a large cross section. However, if the entry of the product is facilitated, its exit is also facilitated. However, it may be necessary to obtain a good aerosol or a good foam, to limit the flow of the product leaving the valve. In the case of two-way valves, it may also be necessary for the two products not to come out with the same flow rate. Similarly, when the two products have different viscosities, it may be necessary to adapt the cross section of the channels to obtain the desired flow rate for each of the products. Until now, the adaptation of the cross section of the channels to guarantee the desired flow of the product or of each of the two products is done in the stem thanks to the choice of the size and the number of the orifices giving access to the tracks of the stem and in the diffuser via the outlet orifice of the nozzle. This means that each stem and nozzle must be adapted case by case, which requires different molds for their manufacture and large stocks. In addition, the choice of the size and the number of the orifices in the stems can limit the speed of filling when the container is filled via the valve, therefore through the stem. The objective of the invention is to allow to adjust the flow rate of a valve, whether one-way or two-way, to the needs related to the products to be applied while maintaining a stem with the widest possible routes . Preferably, the reducer will be designed to allow the other standard components to be retained as well.

This objective is achieved because the flow restrictor is constituted by a separate part of the stem and preferably the diffuser, and which comprises

- a recess open on one side by an opening and adapted to be threaded through the opening on the stem of a valve,

one or more first outlets which, when the gearbox is mounted on the stem of a valve, are able to be sealingly connected to the first channel of the stem of the valve, forming an extension of the first channel,

the outer face of the gearbox, the opposite side to the opening of the recess, preferably having a contour substantially identical to that of the portion of the stem which projects from the valve and which is intended to be covered by the gear.

When the flow reducer is intended for a two-way valve equipped with a two-way stem having a first channel and a second channel, the flow restrictor may further comprise

one or more second outlet orifices, which, when the gearbox is mounted on the stem of a two-way valve, are capable of being sealed to the second path of the stem of the two-way valve by forming an extension the second way,

sealing means which, when the gearbox is mounted on the stem of a two-way valve, are able to maintain the separation of the two tracks at the junction between the gearbox and the stem on which it is mounted and between this junction and the outlets.

Once mounted on the stem, the reducer extends the one or two tracks that remain isolated from each other to the outlets. Simply adjust the number and / or section of the outlets to adjust the flow of products in each channel. It is thus possible to store stems with large section channels and standard diffusers. Only the reducer, simple element to manufacture, is adapted to the case by case. The reducer can be used for single-track stems as well as two-way concentric or two-way parallel stems. Whether it is a single-path stem or a concentric two-way stem, the stem usually has a first tubular wall defining the first path. In this case, the reducer preferably comprises:

a cylindrical first-way wall defining a first-way cylindrical space forming at least a portion of the recess and having a first end facing the opening of the recess and a second end opposite the opening of the recess, the cylindrical wall of the first channel being adapted, when the reducer is mounted on the stem of a valve, to surround at least partly the first tubular wall of the stem; a top closure wall in the extension of the second end of the cylindrical first-way wall, said top closure wall closing the cylindrical first-way space;

the first outlet orifice or openings being made in the top closure wall in an area of the aperture closure wall which, when the reducer is mounted on the stem of a valve, is in contact with the first channel of the stem.

To allow the flow restrictor to have on its outer face opposite to the opening of the recess the shape of the first tubular wall of the stem for which it is intended, it is preferable that

the flow restrictor comprises a cylindrical top wall defining an upper cylindrical space whose cross section is smaller than the cross section of the cylindrical first-track space, and

- the top closure wall is divided into

o a first top closure wall connecting the second end of the first channel cylindrical wall to a first end of the cylindrical top wall; and

a second top closure wall in the extension of the second end of the cylindrical top wall, opposite to the first top closure wall, and closing the summit cylindrical space,

the cylindrical space of the first channel and the summit cylindrical space forming at least part of the recess adapted to be threaded onto a stem;

the first outlet orifice or openings being made in the second top closure wall in an area of the second top closure wall which, when the reducer is mounted on the stem of a valve, is in contact with the first channel; stem.

When the reducer is intended for a concentric two-way valve whose stem has a first tubular wall defining the first channel and a second tubular wall partially surrounding the first tubular wall and defining the second channel, it is preferable that the flow restrictor further comprises

a second-way cylindrical wall defining a second-way cylindrical space forming at least a portion of the recess and having a first end facing the opening of the recess and a second end opposite the opening, the cylindrical wall; second channel being adapted, when the reducer is mounted on the stem of a two-way valve, to surround at least partially the second tubular wall of the stem;

an intermediate closing wall connecting the second end of the cylindrical second-lane wall to the first end of the cylindrical first-lane wall;

the second outlet orifice (s) being (are) formed in the intermediate closure wall in a zone of the intermediate closure wall capable of being in contact with the second path of the stem.

Such a flow restrictor allows a separation of the products until its output. If the separation is to continue to the inside of the diffuser, or even to the exit of the diffuser, the top cylindrical wall and the separation of the top closure wall will be provided in a first and a second top closure wall as indicated previously. If on the contrary, a separation of the products beyond the stem is not necessary, it is possible to give up the cylindrical top wall.

In order to carry out the extension of the second channel, provision may be made to produce one or more channels in the first channel cylindrical wall, which channels extend up to the top closure wall or up to the first top closure wall. and each channel opens onto one or more of the second outlet ports.

To ensure the seal on the one hand at the junction between the flow restrictor and the stem and on the other hand between the extension of the first lane and the extension of the second lane, it is preferable to provide

a first channel sealing tip on the top closure wall or at the first end of the top cylindrical wall, the first channel sealing end being suitable when the reducer is mounted on the stem of a valve two-way, to be introduced into the first path of a valve stem by sealing at the junction between the first path of the valve stem and the flow restrictor, and / or

a second-channel sealing tip placed at the first end of the first-channel cylindrical wall, the second-channel sealing tip being suitable, when the reducing gear is mounted on the stem of a two-way valve, to be introduced into the second path of the stem by sealing at the junction between the second path of the stem and the flow restrictor.

It is preferable that the outer contour of the first-channel cylindrical wall is adapted to cooperate with a diffuser, preferably with a diffuser adapted to cooperate with a stem for which the flow restrictor is intended. In particular, the outer contour of the cylindrical top wall may be adapted to cooperate with a diffuser for a single-way or two-way valve, in particular with a diffuser adapted to cooperate with a stem for which the flow restrictor is intended. In such a case, the outer contour of the gearbox at the level of the cylindrical wall of the first lane and, if appropriate, of the cylindrical top wall is preferably substantially identical to the contour of the stem on which it is mounted so that it co-operates with the diffuser as the stem would have done. It is therefore possible to use the same diffusers for bare stems or stems equipped with a reducer. If it is not necessary to use the same broadcasters and specific broadcasters can be made, we can give up this identity form.

The flow reducer can be sold separately. It can also be sold associated with the valve and / or the diffuser for which it is intended, especially in the form of a set. It is also conceivable that the reducer is sold premounted on the diffuser for which it is intended.

The invention is explained in more detail below using the figures which show:

Fig. 1 sectional view of a flow restrictor according to the invention mounted on a two-channel concentric valve and surmounted by a diffuser;

Fig. 2 perspective view from above of a flow restrictor of the invention;

Fig. Perspective view from below of the flow restrictor of Figure 2;

Fig. 4 sectional view of the reducer of Figure 2 according to the section plane C-C of Figure 9;

Fig. 5 sectional view of the reducer of Figure 2 according to the sectional plane D-D of Figure 9;

Fig. 6 sectional view as in Figure 4, the reducer being mounted on a stem;

Fig. 7 Sectional view as in Figure 5, the reducer being mounted on a stem;

Fig. 8 Cross-sectional view of a two-way stem on which the flow restrictor of the invention can be mounted;

Fig. 9 Bottom view of the reducer of Figure 2; and

Fig. 10 cross-sectional view along section XX of Figure 6 of the flow restrictor of Figure 2 threaded onto the stem of Figure 8 at the second cylindrical wall of the flow restrictor. The invention relates to a flow restrictor (10) for a stem (20) of a one or two-way valve (30) used with a housing (40) in pressure vessels. Such stems (20) are sometimes called valve stems. The flow restrictor is intended to be placed between the free end of the stem (20) protruding out of the valve and the diffuser (50), itself usually placed directly on this projecting end.

In the case of two-way valves, the stems (20) may be of the concentric-channel type as in the example presented here (see in particular FIG. 8), or may be of the parallel-channel type.

A two-way valve stem can be used in a two-way valve (30) with parallel pockets such as that shown by way of example in Figure 1 or concentric pockets (bag-in-bag).

The stem and the flow restrictor of the invention usually have a certain symmetry of rotation around a main axis (A) passing through the stem and the pressure reducer. We will see that this symmetry of rotation is not absolute, some parts of the reducer moving away. The adjectives "axial" or "radial" refer to this main axis (A) and respectively define an element parallel to the axis or perpendicular to this axis. To simplify the description, spatial references such as "high" and "low" or "higher" and "lower" refer to the flow restrictor and stem as shown in Figure 1 for example. These are not absolute positions, the valve on which the flow restrictor of the invention is mounted can be used upwards (as in Fig. 1), downwards, or more generally in any position adapted to the product to be delivered.

A stem for a one-way valve generally comprises a first tubular wall forming a cylindrical channel open upwards and forming part of the single lane. This single path, when the valve is open, communicates with the inside of the housing or with a reservoir placed inside the housing, such as a flexible bag.

When the stem is intended for a two-way valve, this first tubular wall (21) is partially surrounded by a second tubular wall (22) forming an annular channel open upwards and forming part of the second channel. The second tubular wall (22) does not generally extend as high as the first central tubular wall (21). Each path of the stem, when the valve is open, communicates with its respective reservoir, generally a flexible pouch or the inside of the case, in known manner via the valve. It is also possible that the product to be dispensed is contained directly in the housing with the propellant, the product exiting through the first channel and the propellant by the second channel. To simplify the rest of the description, it will generally refer to pockets without this being a limitation, these pockets can be replaced by any other type of tank capable of performing the same function.

The flow restrictor (10) of the invention is slipped on the projecting end of the stem and can maintain the separation of the channels when it is intended for a two-way valve.

The invention is explained in more detail below using a concentric two-way valve reducer. In the example presented here, the flow restrictor (10) consists of three main parts: a first cylindrical wall (1 1), corresponding to the cylindrical wall of the second channel, a second cylindrical wall (12) corresponding to the cylindrical wall of first lane, and a third cylindrical wall (13), corresponding to the cylindrical top wall, each defining a cylindrical interior space.

The first end (lower end) of the first cylindrical wall (1 1) is open and constitutes the lower end of the flow restrictor (10). The second end (upper end) of the first cylindrical wall (1 1) and the first end (lower end) of the second cylindrical wall (12) are connected together by a first radial wall (1 1 1), corresponding to the wall intermediate closure. The second end (upper end) of the second cylindrical wall (12) and the first end (lower end) of the third cylindrical wall (13) are connected together by a second radial wall (121) corresponding to the first closure wall summit. Finally, the third cylindrical wall (13) is closed at its second end (upper end) by a third radial wall (131) corresponding to the second top closure wall. These three radial walls contribute to closing the interior spaces defined by the three cylindrical walls and constitute closure walls. The cylindrical walls and the radial walls together define a recess corresponding to the three cylindrical spaces. The recess is open at the free end of the first cylindrical wall (first end opposite the first closure wall (January 1)). It will be seen that this recess is adapted to be threaded through the opening of the recess on a two-way stem, without the stem necessarily entering the bottom of the recess. In particular, the stem is not intended to penetrate into the summit cylindrical space. The three main walls (1 1, 12, 13) of the flow restrictor (10) are not necessarily absolutely cylindrical. They may be slightly frustoconical, generally not noticeable, to facilitate demolding. This deviation from the perfectly cylindrical shape is expressed by the term "substantially" cylindrical, simplified in the following by the adjective "cylindrical". Similarly, the closing walls (1 1 1, 121, 131) are here radial, but they could be inclined or any other suitable form.

The inside diameter of the first cylindrical wall (1 1) of the flow restrictor is substantially equal to or slightly less than the outside diameter of the second tubular wall (22) of the stem. The inside diameter of the second cylindrical wall (12) is substantially equal to or slightly smaller than the outside diameter of the first tubular wall (21) of the stem. This is clearly visible in Figures 6 and 7.

In addition, the outside diameter of the second cylindrical wall (12) of the flow restrictor is substantially equal to the outside diameter of the second tubular wall (22) of the stem, and the outside diameter of the third cylindrical wall (13) is substantially equal. to the outer diameter of the first tubular wall (21) of the stem. This is also visible in FIGS. 6 and 7. Thus, the outer contour of the gearbox, at the level of the second and third cylindrical walls, is substantially identical to the outer contour of the upper part of the stem intended to penetrate into the diffuser ( 50).

When the flow reducer is mounted on a stem (20), the first tubular wall (21) of the stem penetrates into the second cylindrical wall (12) of the reducer and the second tubular wall (22) of the stem penetrates into the first cylindrical wall (1 1) of the reducer. The inside diameters of the first and second cylindrical walls (1 1, 12) are thus chosen to ensure permanent contact between the inner face of this cylindrical wall (1 1, 12) and the outer face of the tubular wall (21 , 22) corresponding to the stem (see in particular Figures 6 and 7). The assembly requires a slight force to overcome the friction of the walls on each other, which ensures that the restrictor remains on the stem without risk of it going away. The internal diameter of the cylindrical walls (1 1, 12) must not be too small so that the assembly does not require too much force that could damage the stem or the restrictor.

The height of the outer face of the third cylindrical wall (13) is preferably substantially equal to the difference in height between the top of the first tubular wall (21) and the top of the second tubular wall (22) of the stem. The inner height of the first cylindrical wall (1 1) and that of the second cylindrical wall (12) are chosen from such that the two tubular walls (21, 22) of the stem are each in contact with at least a portion of the inner face of the corresponding cylindrical wall (22/1 1, 21/12) when the flow restrictor is mounted on a stem while ensuring on the one hand the continuity of the two channels and on the other hand their tight separation. It is not necessary that the first cylindrical wall (1 1) of the flow restrictor is as high as the projecting portion of the second tubular wall (22) of the stem.

In order to seal between the two channels, the third cylindrical wall (13) can extend downwards, inside the second cylindrical wall (12), by a first-way sealing tip (132). ) whose outer diameter is substantially equal to the inner diameter of the first tubular wall (21) of the stem. Similarly, the second cylindrical wall (12) of the reducer can extend downwards, inside the first cylindrical wall (1 1), by a second-channel sealing tip (122) whose outer diameter is substantially equal to the inside diameter of the second tubular wall (22) of the stem. Due to the tight fitting of the first cylindrical wall (1 1) on the second tubular wall (22) of the stem on the one hand, and the second cylindrical wall (12) on the first tubular wall (21) of the stem of on the other hand, it would be possible to give up the second channel seal (122).

To facilitate the introduction of the gear on the stem, it is preferable to chamfer the inside of the first and second cylindrical wall (1 1, 12) at their respective lower ends to allow a self-centering effect of the reducer with respect to the stem. When a second channel sealing tip (122) is provided, it is sufficient to chamfer the inner face thereof, without the chamfer necessarily reaching the inner face of the second cylindrical wall (12). Similarly, it is possible to chamfer the outer face of the two sealing caps (121, 131).

A central channel (133) of substantially constant diameter passes through the third cylindrical wall (13) from its lower end, or the lower end of the sealing cap (132) when there is one, to the third radial wall (131) closing the third cylindrical wall (13). A central outlet (134) is formed in the third radial wall to contact the central channel (133) and the exterior of the reducer. This outlet (124) corresponds to one of the first outlets. Rather than a single orifice, it would be possible to make several orifices in the third radial wall (131). Similarly, one or more side channels (123), here two, can be made in the thickness of the second cylindrical wall (12). These channels extend from the lower end of the second wall cylindrical, or second channel sealing tip (121) when there is one, to the second radial wall (121) closing the second cylindrical wall. Each side channel (123) terminates in one or more outlets (124) formed in the second radial wall (121) closing the second cylindrical wall. These outlets (124) correspond to the second outlets. The side channels (123) can be made entirely in the mass of the cylindrical wall (12), or only be partially included in this wall, as is the case in the example presented here. This is clearly visible in FIGS. 3 and 5. In this case, the outer face of the first tubular wall (21) of the stem closes the lateral wall of the tubular channels (123) as shown in FIG. 6 and FIG.

The flow restrictor (10) is preferably made of a plastic material, for example a flexible polyolefin to facilitate tight fitting and participate in the sealing of the tip (10) on the stem (20).

When the flow reducer is mounted on a stem, the product contained in the first tank (usually a first pocket) leaves the valve by the first channel, which ends in the central channel located in the first tubular wall (21). stem. The product leaving the stem through this first channel enters the central channel (133) of the third cylindrical wall of the flow restrictor and exits through the outlet port (134) at the top of the restrictor. The central channel (133) is therefore an extension of the first channel. The product contained in the second pocket (or in the housing) out of the valve by the second path, which ends in the annular channel defined between the first tubular wall (21) and the second tubular wall (22) of the stem. The product leaving the stem by this second channel enters the two lateral channels (123) and exits through the outlet orifices (124) located on the second radial wall (121) at the junction between the second and the third cylindrical wall (12). , 13). The side channels (123) therefore constitute an extension of the second channel. Leaving the orifices (124, 134), the products enter the diffuser as they would have if they had left the stem directly. The first channel sealing tip (132) ensures separation of the two products. The sealing tip (122) of the second channel contributes to the sealing of the second channel relative to the outside.

The cross-section of the outlets (124, 134) and / or the number of lateral channels (123) are chosen according to the needs, namely the ratio between the two products to be dispensed taking into account the viscosity of each. It is therefore possible to have several different flow restrictors for the same set of stem and diffuser. A stem with two tracks of large cross-sections is preserved, allowing a rapid filling of pockets, while being able to adapt the output flow rate with the reducer of the invention. Because of its outer contour with the same dimensions as those of the stem, it is not necessary to modify the diffusers that can be transferred to the gearbox as they would on a stem. At most we can adapt the height of the diffuser skirt to compensate for the additional height due to the presence of the flow restrictor if it is necessary for this skirt to go down to the cup of the valve or to the housing. The gearbox can be delivered alone, mounted in a diffuser or placed temporarily on a two-way valve.

If the separation of the channels is no longer necessary to exit the valve, it is possible to give up the third cylindrical wall (13). In this case, the second radial wall (121) closing the top of the second cylindrical wall (12) extends over the entire cross section of the channel defined by the cylindrical wall (12), the central outlet (134) being made in the center of this radial wall (121) so as to be in front of the first path of the stem defined by the first tubular wall (21). It is even conceivable to give up the first channel sealing tip (131).

Those skilled in the art understand that the system can be adapted to parallel rather than concentric channel stems. In this case, the flow restrictor is provided with two non-concentric parallel channels each with one or more outlet orifices whose cross section is adjusted on a case by case basis.

It should be noted that the flow restrictor of the invention has almost no effect on the pressure and does not fulfill the function of a pressure reducer.

When the flow reducer is intended for a single-way valve, it is not necessary to provide the first cylindrical wall (1 1), or the channels (123) and the second openings (124).

Those skilled in the art also understand that it would be possible to adapt the flow restrictor to stems comprising more than two channels, for example parallel or concentric three-way stems.

The reducing agent of the invention can be used for any type of aerosol, for the application of pasty products, for foams, gels or liquids. It can be applied to pocket valves whose pockets can be welded or snapped onto the valve body. List of references:

10 Flow reducer

11 First cylindrical wall (cylindrical second-lane wall)

11 1 First radial wall (intermediate radial wall) 12 Second cylindrical wall (first radial wall)

121 Second radial wall (first top closure wall)

122 Second way seal

123 Lateral channels

124 2nd side exit ports

13 Third cylindrical wall (cylindrical top wall)

131 Third radial wall (second top closure wall)

132 First-line seal

133 Central exit channel

134 ^1st central outlet

20 Stem

21 First tubular wall

22 Second tubular wall

30 Valve

40 Case

50 Diffuser

A Main axis

Claims

claims

Flow restrictor (10) for a pressurized product dispenser of the type equipped with a diffuser and a valve (30) equipped with a stem (20) having at least a first channel, characterized in that the flow reducer (10) is a separate part of the stem and the diffuser, and in that it comprises

- a recess open on one side by an opening and adapted to be threaded through the opening on the stem (20) of a valve (30),

- one or more first outlets (134) which, when the gearbox is mounted on the stem (20) of a valve, are adapted to be sealingly connected to the first path of the stem

(20) of the valve forming an extension (133) of the first channel,

the outer face of the gearbox, on the opposite side to the opening of the recess, having in part an outline substantially identical to that of the part of the stem (20) which projects from the valve and which is intended to be covered by the gearbox .

Flow restrictor (10) according to claim 1, for a two-way valve (30) equipped with a two-way stem (20) having a first channel and a second channel, characterized in that the reducer of flow (10) comprises:

one or more second outlet orifices (124) which, when the reducer is mounted on the stem of a two-way valve, are capable of being sealed to the second channel of the stem (20) of the valve; two channels forming an extension (123) of the second channel,

- Sealing means (132) which, when the reducer is mounted on the stem of a two-way valve, are able to maintain the separation of the two channels at the junction between the reducer and the stem on which it is mounted and between this junction and the outlets (124, 134).

3. Flow reducer (10) according to one of the preceding claims for a valve (30) equipped with a stem (20) having at least a first tubular wall (21) defining the first channel, characterized in that the reducer includes

a first-channel cylindrical wall defining a cylindrical first-way space forming at least a portion of the recess and having a first end directed towards the opening of the recess and a second end opposite the opening of the recess; the recess, the first-way cylindrical wall (12) being suitable, when the gearbox is mounted on the stem of a valve, at least partially surrounding the first tubular wall (21) of the stem:

- a top closure wall (121, 131) in the extension of the second end of the first channel cylindrical wall (12), said top closure wall (121, 131) closing the cylindrical space of first path;

the first outlet orifices (134) being made in the top closure wall (131) in a zone of the top closure wall (131) adapted, when the gearbox is mounted on the stem of a valve, to to be in contact with the first path of the stem.

4. Flow reducer (10) according to the preceding claim, characterized in that

the flow restrictor comprises a cylindrical upper wall defining an upper cylindrical space whose cross section is smaller than the cross section of the cylindrical space of the first lane, and in that

- the top closure wall is divided into

a first top closure wall (121) connecting the second end of the first channel cylindrical wall (12) to a first end of the top cylindrical wall (13); and

a second top closure wall (131) extending from the second end of the cylindrical upper wall (13), opposite the first top closure wall (121), and closing the summit cylindrical space,

the first outlet orifices (134) being made in the second top closure wall (131) in an area of the second top closure wall (131) adapted, when the gearbox is mounted on the stem of a valve , to be in contact with the first path of the stem.

A flow restrictor (10) according to claim 3 or 4 for a concentric two-way valve stem (20) having a first tubular wall (21) defining the first channel and a second tubular wall (22). partially surrounding the first tubular wall (21) and defining the second channel, characterized in that it further comprises:

a second-channel cylindrical wall (1 1) defining a cylindrical second-way space forming at least a portion of the recess and having a first end directed towards the opening of the recess and a second end opposite the opening; the cylindrical second-lane wall (1 1) being suitable, when the gearbox is mounted on the stem of a two-way valve, to surround at least part of the second tubular wall (22) of the stem; - an intermediate closure wall (11 1) connecting the second end of the second channel cylindrical wall (1 1) to the first end of the first channel cylindrical wall (12);

- Or the second outlet orifices (124) being formed in the intermediate closure wall (121) in a region of the intermediate closure wall (121) adapted to be in contact with the second path of the stem.

Flow restrictor according to Claim 5, characterized in that one or more channels (123) are formed in the cylindrical first-channel wall (12), which channels extend as far as the top closure wall or up to to the first top closure wall (121) and each channel (123) opens onto one or more of the second outlet ports (124).

Flow restrictor according to one of Claims 5 or 6, characterized in that

a first-channel sealing cap (132) is provided on the top closure wall or at the first end of the top cylindrical wall (13), the first-way sealing cap (132) being suitable, when the reducer is mounted on the stem of a two-way valve, to be introduced into the first path of the stem by sealing at the junction between the first path of the stem and the flow restrictor, and / or in that '

a second-channel sealing tip (122) is provided at the first end of the first-channel cylindrical wall (12), the second-channel sealing tip (122) being suitable when the gearbox is mounted on the stem of a two-way valve, to be introduced into the second path of the stem by sealing at the junction between the second path of the stem and the flow restrictor. 8. Flow restrictor (10) according to one of claims 3 to 7, characterized in that the outer contour of the first channel cylindrical wall (12) is adapted to cooperate with a diffuser, preferably with a diffuser adapted to cooperate with a stem for which the flow restrictor is intended. 9. Flow restrictor (10) according to one of the preceding claims associated with claim 4, characterized in that the outer contour of the cylindrical upper wall (13) is adapted to cooperate with a diffuser for two-way valve, of preferably with a diffuser adapted to cooperate with a stem for which the flow restrictor is intended.

10. Flow restrictor (10) according to one of the preceding claims, characterized in that it is mounted on a diffuser, preferably a single-channel or two-way at least partly separate diffuser. 11. Kit consisting of at least one valve provided with a stem and at least one flow restrictor (10) according to one of the preceding claims.