EP2916963A1 - Fluid product tank - Google Patents

Abstract

A fluid product tank comprising: a sliding barrel (11), a neck (12) defining an outlet opening (13), an inner shoulder (14) linking the sliding barrel (11) to the outlet opening (13), the inner shoulder (14) being provided with an annular groove (15) that extends into the extension of the sliding barrel (11) such that the inner shoulder (14) defines an annular ring (16) that links the annular groove (15) to the outlet opening (13), - a follower piston (2) sealingly and slidingly engaged in the sliding barrel (11), the piston (2) defining at least one sealing lip (21) that is received in the annular groove (15) when the tank is empty, characterised in that the annular ring (16) is formed with at least one radial groove (17; 17') that links the annular groove (15) to the outlet opening (13) of the neck (11).

Description

 Fluid tank

The present invention relates to a reservoir comprising a sliding shaft, a collar defining an outlet opening, an internal shoulder connecting the sliding shaft to the outlet opening and a follower piston engaged to slide in the sliding shaft, the piston defining at least one sealing lip. This type of tank is frequently used in the field of cosmetics, or more generally for storing sensitive or fragile fluid products. Indeed, this type of piston follower tank stores the fluid without it never in contact with air. This is possible since the displacement of the follower piston makes it possible to vary the useful volume of the reservoir as fluid is extracted from it. Advantageously using a dispensing member without air intake, it is ensured that the fluid product stored in the tank is never in contact with air.

 A conventional problem inherent in the follower piston lies in the fact that it is difficult to extract all of the fluid product stored in the tank. Indeed, due to the configuration of the follower piston of the tank shoulder and the dispensing member (pump), it is virtually impossible to completely empty the tank. This is called fluid restitution or restitution rate, characteristic of the capacity of the tank to be emptied more or less perfectly.

 An object of the present invention is to increase this rate of refund by minimizing the volume of fluid that remains stored in the reservoir when the follower piston has completed its course.

Another problem with the piston follower tanks is related to its vacuum packaging. Indeed, when filling the tank, it is common for air pockets to form under the internal shoulder near the sliding shaft. This is easily explained by the fact that the tank forms at this point a zone with difficulty refillable, especially because of gravity. During vacuum packaging, the tank filled with fluid product is subjected to a depression more or less deep in order to remove the air from the tank. When an air pocket is present under the internal shoulder, the depression of the reservoir generates an expansion of volume of the air pocket, which has the effect of quickly up fluid in the opening of the collar. It sometimes results that fluid flows out of the neck and contaminates the outside of the tank, which is of course not acceptable.

 The present invention therefore also aims to overcome this drawback related to the vacuum packaging of the tank.

 To achieve these various objects, the present invention provides a fluid reservoir comprising a slide shaft, a neck defining an exit opening, an internal shoulder connecting the slide shaft to the exit opening, the inner shoulder being provided. an annular groove which extends in the extension of the sliding shaft so that the internal shoulder defines an annular ring which connects the annular groove to the outlet opening, a follower piston engaged in the sealing shaft sliding, the piston defining at least one sealing lip which is received in the annular groove when the reservoir is empty, the annular ring being formed with at least one radial groove which connects the annular groove to the outlet opening of the neck.

Advantageously, the annular ring comprises a plurality of radial grooves. These radial grooves which connect the sliding shaft to the outlet opening of the neck at the internal shoulder can evacuate any air pockets that would have formed under the shoulder during filling of the tank. These radial grooves are all the more useful that the reservoir is provided with an annular groove for receiving the upper lip of the piston, since this annular groove has the effect of promoting the formation of air pockets. There is therefore a real synergy between the annular groove and the radial grooves on the one hand to increase the rate of return of the reservoir and on the other hand to evacuate the air possibly trapped under the shoulder and in the annular groove . Advantageously, the groove and said at least one groove have respective bottoms which connect continuously. Thus, the groove communicates directly and without discontinuity with the groove, thus optimizing the evacuation of air possibly trapped. According to another interesting characteristic, the bottom of said at least one groove extends inclined upwards of the groove towards the opening. In this way, the air possibly trapped can still very easily be evacuated towards the opening of the neck. According to another characteristic of the invention, said at least one groove has a trapezoidal or triangular section. This configuration makes it possible to promote the evacuation of the air possibly trapped while limiting the total cumulative volume of the grooves, which increases the rate of restitution.

 Advantageously, the follower piston comprises a plate, the lip protruding from the plate, so that the plate is in contact with the crown when the lip is received in the groove. This further increases the rate of return of the tank by minimizing its dead volume. According to another advantageous characteristic, the follower piston comprises a central cup which extends substantially in the extension of the opening of the neck to receive a lower part of a pump or a valve. According to a practical and conventional embodiment, the follower piston comprises a lower lip and an upper lip in leaktight sliding in the barrel, the upper lip being received in the groove when the reservoir is empty. Preferably, the annular groove has a section of shape substantially similar to that of the lip.

The spirit of the invention lies in the optimization of the restitution rate of the follower piston tank by providing a housing for the upper lip of the follower piston at the end of its stroke. However, this feature promotes the formation of air pockets during filling of the tank, the air of these pockets being evacuated due to the presence of radial grooves which connect the annular groove to the outlet opening of the neck. The invention will now be further described with reference to the accompanying drawings, giving by way of non-limiting examples two embodiments of the invention.

 In the figures:

 Fig. 1a is a vertical cross-sectional view through a reservoir of the present invention with the follower piston in the down position,

FIG. 1b is a view similar to that of FIG. 1a with the follower piston in the high position,

 FIG. 2a is a greatly enlarged view of part A of FIG. 1b,

 FIG. 2b is a view similar to that of FIG. 2a according to a different sectional plane, and

 Figure 3 is a view similar to that of Figure 2b for a second embodiment of the invention.

 Reference will firstly be made to FIGS. 1a to 2b to describe the first embodiment of a follower piston container according to the invention. The reservoir comprises three constituent elements, namely a tank body 1, a follower piston 2 and optionally a bottom 3. These three constituent elements can be made by injection molding of suitable plastic material. The tank body 1 may optionally be made of glass, ceramic or metal.

The reservoir body 1 here has the particularity to consist of two components, namely an external component 1a and an internal component 1b, and this for reasons including aesthetic. Indeed, the inner component 1b can be made of an opaque material while the outer component 1a can be made of a transparent material so that the inner component 1b can be visible through the transparent outer component 1a. The outer component 1a may for example be overmolded on the inner component 1b. These two components 1a, 1b together form the tank body 1. In this context, it can be considered that the reservoir body forms an inner sliding shaft 1 1 of substantially or perfectly cylindrical shape. This shaft is here formed by the wall internal component 1 b. At its upper end, the reservoir body 1 forms a shoulder 14 of substantially annular shape which connects the sliding spring 1 1 to an outlet opening 13 which is here defined by a protruding neck 12. The inner part of the shoulder 14 here is formed by the internal component 1b. The outer portion of the shoulder is formed by the outer portion 1a and connects the outer wall of the tank body to the outer portion of the neck 12. The outlet opening 13 is partially formed by the inner component 1b and the component external 1 a. At its lower end, the tank body 1 forms several steps allowing a fixed and final reception of the bottom 3.

 The follower piston 2 is received inside the slider 1 1 so as to move there sealingly. The follower piston 2 comprises an outer skirt 20 forming an upper annular sealing lip 21 and a lower annular sealing lip 22 which both slide sealingly inside the barrel 11. From this skirt 20, the follower piston 2 forms an annular plate 23 which extends inwards to the level of a central cup 24 which forms a recess with respect to the plate 23. In the configuration shown in FIG. 1a, the follower piston 2 is in its maximum low position, the bucket 24 being in contact with the bottom 3. The two annular sealing lips 21 and 22 are in contact with the slider 1 1. This configuration corresponds to that in which the tank is filled to a maximum. Indeed, the volume of the tank above the follower piston 2 is maximum, while the volume defined below the follower piston 2 is minimal.

Although not shown, a dispensing member, such as a pump without air intake, is intended to be mounted on the neck 12 extending into the outlet opening 13, so as to be able to withdraw the fluid product. stored in the tank. Each time the pump is actuated, a dose of fluid is dispensed and a dose of fluid is withdrawn from the reservoir. This causes a depression inside the tank which has the effect of displacing the follower piston 2 by suction towards the opening 13. When the follower piston 2 has come into contact with the shoulder 14, the tank has a minimum volume. It can be seen in Figure 1b that the bucket 24 of the follower piston is located axially just below the outlet opening 13 so as to accommodate the lower part of the dispensing member (pump).

 According to the invention, the shoulder 14, at the point where it connects to the upper end of the sliding shaft 1 1, forms an annular groove 15, in which the upper sealing lip 21 of the follower piston 2 is received, when the reservoir is empty, as shown in Figures 1b, 2a and 2b. It may even be noted that the shape of this annular groove 15 in cross section corresponds roughly or substantially to the cross-sectional shape of the upper lip 21, so that a minimum dead volume remains in the groove 15 when the lip 21 is there received. An annular ring 16 is thus formed between the annular groove 15 and the opening 13. This ring 16 is defined by the lower wall of the shoulder 14. On the other hand, it is advantageous for the plate 23 to come into contact or to direct proximity of the crown 16. Thus, there remains very little fluid between the follower piston and the shoulder 14. In other words, the annular groove 15 can significantly improve the rate of return of the reservoir .

According to another advantageous characteristic of the invention, several radial grooves 17 are formed in the ring 16 of the shoulder 14: they radially connect the annular groove 15 to the outlet opening 13. This is clearly visible in FIG. is a section in cross section which passes through two opposite radial grooves 17. In this non-limiting configuration, the ring 16 is provided with six radial grooves 17. Without departing from the scope of the invention, it can provide a single radial groove. It can also be seen in Figure 2b that the bottom of the grooves 17 extends in alignment with the bottom of the groove 15. Thus, there is no discontinuity or step or relief or depression between the groove and the grooves. In this first embodiment, the bottom of the grooves 17 extends at the same axial height as the bottom of the groove 15. Referring to the second embodiment shown in Figure 3, it can be seen that the reservoir is made integrally. In addition, there is another type of radial grooves 17 'whose bottom is certainly connected continuously to the bottom of the groove 15, but extends inclined upwards to open up in the outlet opening 13 While the cross section of the grooves 17 is substantially trapezoidal in shape, the cross section of the grooves 17 is rather triangular in shape.

According to the invention, the function of the radial grooves 17, 17 'is to provide an evacuation path for air possibly trapped inside the reservoir at the level of the shoulder 14. Indeed, when one fills a follower piston tank with a viscous product such as cream, it is very difficult to fill the area located at the angle between the shoulder 14 and the barrel January 1, precisely at the annular groove 15. this means that one or more pockets of air can form at this point, and during vacuum packaging, these air pockets undergo a very rapid volume expansion, which can lead to a sudden rise in fluid. in the outlet opening 13. Therefore, it is necessary to be able to evacuate the air from these pockets through the outlet opening without they can undergo volumetric expansion. The radial grooves 17, 17 'thus provide an evacuation passage which directly connects the zone of formation of the air pockets to the outlet opening 13. Without the radial grooves of the invention, the phenomenon of pocket formation of The air would be further amplified due to the presence of the annular groove 15 which is precisely located at the area of formation of the air pockets. Thus, by directly connecting the annular groove to the outlet opening 13, the radial grooves 17, 17 'ensure complete evacuation of the air possibly trapped under the shoulder 14. On the other hand, because of their trapezoidal or triangular shape, the total cumulative volume of the grooves is greatly reduced, thereby reducing the dead volume of the tank when empty. Indeed, the dead volume of the tank is mainly constituted by the volume of the grooves 17 and a portion of the bucket 14, since the plate 23 comes into contact with or in the direct vicinity of the shoulder 14 and that the groove 15 is substantially completely filled by the upper sealing lip 21.

 Thanks to the invention, not only the tank recovery rate is considerably increased by housing the upper lip of the follower piston in an annular receiving groove of appropriate shape, but also the air possibly trapped in the reservoir at this groove The annulus can be evacuated through radial grooves that connect the groove to the outlet opening.

Claims

claims 1. - Fluid product reservoir comprising:  a sliding shaft (1 1),  a neck (12) defining an outlet opening (13),  - an internal shoulder (14) connecting the sliding shaft (1 1) to the outlet opening (13), the inner shoulder (14) being provided with an annular groove (15) extending in the extension sliding barrel (1 1) so that the inner shoulder (14) defines an annular ring (16) which connects the annular groove (15) to the outlet opening (13),  - a follower piston (2) slidably engaged in the sliding shaft (1 1), the piston (2) defining at least one sealing lip (21) which is received in the annular groove (15) when the reservoir is empty,  characterized in that the annular ring (16) is formed with at least one radial groove (17; 17 ') which connects the annular groove (15) to the outlet opening (13) of the neck (1 1). 2. - The tank of claim 14, wherein the annular ring (16) comprises a plurality of radial grooves (17; 17 '). 3. - Tank according to claim 1 or 2, wherein the annular groove (15) and said at least one radial groove (17; 17 ') have respective bottoms which connect continuously. 4. A tank according to claim 3, wherein the bottom of said at least one radial groove (17 ') extends inclined upwards of the annular groove (15) towards the outlet opening (13). 5. A tank according to any one of the preceding claims, wherein said at least one radial groove (17; 17 ') has a trapezoidal or triangular section. 6. Tank according to any one of the preceding claims, wherein the follower piston (2) comprises a plate (23), the sealing lip (21) protruding from the plate (23), so that the plate (23) is in contact with the annular ring (16), when the sealing lip (21) is received in the annular groove (15). 7. - Tank according to any one of the preceding claims, wherein the follower piston (2) comprises a central cup (24) which extends substantially in the extension of the outlet opening (13) of the neck (1 1 ) to receive a lower part of a pump or a valve. 8. - Tank according to any one of the preceding claims, wherein the follower piston (2) comprises an upper sealing lip (21) and a lower sealing lip (22) in sliding sliding in the sliding barrel ( 1 1), the upper sealing lip (21) being received in the annular groove (15), when the reservoir is empty. 9. A tank according to any one of the preceding claims, wherein the annular groove (15) has a section of substantially similar shape to that of the sealing lip (21).