WO1996012567A1

WO1996012567A1 - Liquid atomizer

Info

Publication number: WO1996012567A1
Application number: PCT/FR1995/001375
Authority: WO
Inventors: Michel André LAPAUTRE; Marc Lepretre
Original assignee: Bertin & Cie.
Priority date: 1994-10-20
Filing date: 1995-10-18
Publication date: 1996-05-02
Also published as: FR2725921A1; FR2725921B1

Abstract

Atomizer (3) comprising a pump for drawing a predetermined volume of liquid from a container comprising a generally cylindrical chamber (5) in which slides a piston (6), means for linking the chamber (5) to a nozzle (12) for spraying liquid contained in said chamber and means (13) for actuating the piston (6) and compressing the liquid to force the compressed liquid through the nozzle. The atomizer (3) also comprises a spring-loaded bistable valve (14) which opens fully when a predetermined value (P0) of liquid pressure is attained in the chamber and closes fully when the pressure falls below a lesser predetermined value. The atomizer of the invention is suitable for spraying perfume and cosmetic products.

Description

LIQUID SPRAYER

The present invention relates to a liquid sprayer and, more particularly, to such a sprayer of the type which comprises a pump formed by a generally cylindrical chamber in which slides a piston for withdrawing a predetermined volume of liquid in a tank, means to communicate the chamber, through the piston, with a nozzle for spraying the liquid contained therein and means for actuating the piston and thus compress this liquid so as to cause the spraying by the nozzle of the compressed liquid.

In the cosmetics industry, manually operated sprayers are commonly used to spray various products such as hair sprays, deodorants, perfumes, etc.

Known sprayers commonly include a miniature pump for withdrawing a predetermined volume of the liquid in a tank and for compressing this volume so as to conduct a liquid under pressure in a spray nozzle. Ideally, it is necessary to have a relatively high pressure (of the order of ten bars or more) to obtain fine droplets, and of a very constant level so that the diameter of these droplets does not vary according to the pressure, during spraying. It should be noted in this regard that a constant diameter of droplets makes it possible to ensure a uniform distribution of the product, which is important in particular in the case of hair sprays. These pumps are known under the generic name of precompression pumps. When measuring the pressure of liquid supplied by sprayers with manual actuation of the prior art, during a spraying, pressure variations as a function of time are noted, illustrated by the graph À in FIG. 4 of the drawing appended to this description. This graph shows a gradual rise in pressure then a gradual fall in this pressure. The wide pressure variations that we observe then do not allow to diffuse droplets of liquid of constant diameter throughout the spraying. In addition, the maximum pressure levels reached (a few bars) do not give the droplets the desirable fineness, that is to say droplets having a diameter of a few tens of μm.

The present invention therefore aims to achieve a sprayer which ensures the establishment of a high and constant liquid pressure throughout the duration of a manually actuated spraying, so as to produce fine droplets of constant diameter.

The present invention also aims to achieve such a vaporizer which is of simple design and assembly, allowing manufacture at reduced cost. These objects of the invention are achieved, as well as others which will appear on reading the description which follows, with a liquid sprayer of the type which comprises a pump formed by a generally cylindrical chamber in which a piston slides, for withdrawing a predetermined volume of liquid from a reservoir, means for communicating the chamber with a nozzle for spraying the liquid contained therein and means for actuating the piston and thus compressing this liquid so as to cause spraying by the nozzle of the compressed liquid. According to the invention, the means of communication between the chamber and the nozzle comprise a bistable valve calibrated so as to open completely for a predetermined value of the pressure of the liquid in the chamber and to close completely when the pressure of this liquid falls below another predetermined value, lower than the previous one.

As will be seen later, thanks to the use of such a valve, a perfectly constant liquid pressure is obtained during spraying, which ensures the consistency of the diameter of the droplets formed by the sprayer. According to the invention, the valve cooperates with a seat of diameter much less than the diameter of a compartment cylindrical in which it slides and which communicates with the spray nozzle. Thanks to the amplification of force thus obtained, the valve suddenly and surely moves away from its seat from the predetermined value of the pressure of the liquid reached and remains ee-e of this seat as long as the pressure of the liquid in the chamber remains greater than or equal to the other predetermined value. Stop means stop the valve in a predetermined position when it deviates from its seat. Other characteristics and advantages of the present invention will appear on reading the description which follows and on examining the appended drawing in which:

FIG. 1A is a partial diagram in axial section of a sprayer according to the invention, FIG. 1B is a diagram of the bistable valve incorporated in the sprayer of FIG. 1A,

FIG. 2 schematically represents a variant of the actuation means of the sprayer of FIG. 1A,

FIG. 3 schematically represents another embodiment of the sprayer according to the invention, and

- Figure 4 shows graphs which compare the performance of the sprayer according to the invention to that of sprayers of the prior art.

Referring to FIG. 1A which schematically represents a sprayer according to the invention, mounted on a reservoir 1 of a cosmetic product to be sprayed, lacquer, deodorant, perfume, etc. The reservoir 1, a bottle for example, comprises a threaded neck 2 onto which the sprayer 3 is screwed, which includes a base 4 which is additionally threaded.

The sprayer comprises a pump 5,6 consisting of a generally cylindrical chamber 5 in which slides a piston 6 axially provided with a seal 6 _ι . The chamber 5 communicates with the bottle 1 by a non-return valve 7 and a dip tube 8 which sinks into the mass of liquid contained in the bottle l. A coil spring 9 charges the piston 6 to its position high (from the point of view of the figure) away from the end of the chamber 5 where the non-return valve 7 is located.

The piston 6 is extended by a hollow rod 10 which slides in a guide tip 11 integral with the base 4 of the sprayer and coaxial with the chamber 5. This hollow rod puts the chamber 5 and a nozzle 12 in communication with fluid. axis perpendicular to that of the rod 10, mounted on a cap 13 integral with the piston 6 and the rod 10.

According to the present invention, a bistable valve 14 provided with a seal 14i (see FIG. 1B) controls the placing in communication of fluid between the chamber 5 and the nozzle 12. The valve 14 slides in a compartment 15 coaxial with the rod 10 of the piston and formed in one piece with the cap 13. This compartment is closed by a plug 16 screwed or welded. The opening of the valve is calibrated by a spring 17 which loads the valve against its seat 18. A passage 19 communicates the hollow rod of the piston with the nozzle 12 when the valve 14 is moved away from its seat.

The sprayer described above then operates as follows. The mechanical energy necessary for this operation is supplied by a user who manually presses on the upper part of the cap 13 to cause the liquid to spray. From a low position of this cap, and when the pressure exerted by the user on this cap is released, the spring 9 returns the piston 6 and the cap 13 upwards.

(from the point of view of the figure) thereby causing a suction of the liquid contained in the bottle 1 through the non-return valve 7 raised from its seat. This suction fills the chamber 5. A new pressure on the cap 13 has the effect of causing a pressurization of the liquid contained in the chamber 5, under the thrust of the piston 6 secured to the cap. When the liquid pressure reaches a predetermined value, the bi-stable valve 14 lifts from its seat, creating a passage for the pressurized liquid, which then arrives in the nozzle

12. This delivers the liquid outside the sprayer, in the form of a cloud of fine droplets. As seen above, the fineness and constancy of the diameter of these droplets depends on the level of the pressure of the liquid at the nozzle, and on the constancy of this pressure. The bistable valve 14 makes it possible to precisely define this pressure of the liquid. The latter is in fact calibrated by a spring 17, the stiffness of which can be chosen so that the valve does not lift until during the application of a force F _R such that:

P ₀ being the pressure of the liquid which balances the force F „exerted by the spring 17 on the valve, and d the diameter of the seat of this valve. A suitable choice of F „and / or d allows P ₀ to be fixed.

This pressure being reached, the valve lifts and then undergoes a force F such that:

F ~ P, _X -

D being the diameter of the valve, chosen slightly greater than d.

The force F, greater than F „, then presses the valve on stop means which define a fixed position for the valve, when the latter is moved away from its seat. The valve is said to be "bistable" because it thus switches between two perfectly defined positions.

It will be noted that, very advantageously according to the invention, the amplification in the ratio (D / d) ² of the force which acts on the valve 14, when it opens, ensures rapid tilting of the valve d '' one position to another, without erratic passages in intermediate positions which would cause variable pressure losses in the space separating the valve from its seat, pressure losses which would adversely affect the constancy of the pressure of the liquid in the nozzle 12.

According to one embodiment of the invention, the abutment means defining the separated position of the valve 14 are constituted by the base of the plug 16 of the compartment 15, a plug whose height then limits the stroke h of the valve when the latter passes from one position to the other. To minimize the pressure losses between valve and seat, you will advantageously choose:

h ≤

4 to thereby ensure at least the balancing of the inlet and outlet flow rates of the valve seat.

Observations have shown that, for an appropriate sampling of users, the speed v of displacement of the piston is approximately constant and that the pressure P depends practically only on the diameters of the chamber 5 and on the outlet orifice of the nozzle 12.

It now appears that the invention makes it possible to supply the nozzle with a liquid at a substantially constant pressure, throughout the duration of manual actuation of the piston. As we saw above, this pressure can advantageously be quite high, of the order of ten bars for example, to ensure the production of droplets of adequate fineness. The higher the desired pressure, the greater the force to be applied to the piston and it is then necessary to provide means for amplifying the force developed by the user, so as not to make it too painful.

According to the present invention, this object is achieved by incorporating into the sprayer the actuation means shown in FIG. 2, given only by way of illustrative and nonlimiting example. In this figure and in Figure 3, identical references to references used in Figure 1 identify identical or similar elements or bodies. Thus we find in Figure 2 the base 4, the chamber 5, the piston 6, the rod 10, the nozzle 12, the cap 13 and the valve 14 of the sprayer of Figure 1A. The cap 13 is fixed and not movable as that of FIG. 1A. It is further modified so as to support by a hinge 20 a lever 21 which projects beyond the cap and which is supported on a roller 22 secured to the nozzle 12, the valve 14. and the rod 10 of the piston. When the user presses on the free end of the lever 21, a multiplied force in the ratio of the lever arms in question is applied by the lever 21 to the piston 6, for the generation of a pressure of liquid in relation to the chamber 5. There is shown in Figure 3 another embodiment of the sprayer according to the invention, which differs from that of Figure 1 in that the spray nozzle 12 is fixed and not movable. This nozzle is in fact integral with the chamber 5 of the pump, to which it is connected, through the bi-stable valve 14, by a conduit 23 formed in the wall of the chamber 5. The cap 13 is cut from a lateral window 24 releasing the nozzle 12, in order to be able to move axially without abutting on the latter. FIG. 4, already mentioned in the preamble to the present description, illustrates the advantages which one derives from the present invention. Graph B of this figure shows the typical shape of the evolution of the pressure of the liquid during actuation of the sprayer according to the invention. This has a long plate, which can be fixed at 10 bars for example, pressure much higher than that obtained with sprayers of the prior art, and frank upward and downward pressure, at the ends of this plate, in accordance with the objectives that we had set for ourselves.

It will also be noted that the sprayer according to the invention is of particularly simple design, the bistable valve being outside the chamber and not inside the chamber as is often the case of the non-bistable valves used in the prior art . The assembly of such a sprayer is simplified and its manufacturing cost lowered. Of course, the invention is not limited to the embodiments described and shown and to the applications mentioned. Thus, known force amplification means, other than those represented in FIG. 2, could be incorporated into the sprayer according to the invention, in place of these. In addition, the invention is not limited to the spraying of cosmetic products and of course extends to the spraying of all liquid products, such as household or phytosanitary products for example.

Claims

CLAIMS 1. Liquid sprayer, of the type which includes a pump for withdrawing a predetermined volume of liquid from a reservoir, formed of a generally cylindrical chamber (5) in which a piston (6) slides, means (10; 23) for communicating the chamber (5) with a spray nozzle (12) of the liquid contained therein and means for actuating the piston (6) and thus compressing this liquid so as to cause spraying by the nozzle (12) compressed liquid, characterized in that the means of communication between the chamber and the nozzle comprise a bistable valve (14) calibrated so as to open completely for a predetermined value (P ₀ ) of the pressure of the liquid in the chamber and to close completely when the pressure of this liquid falls below another predetermined value, lower than the previous one.

2. Sprayer according to claim 1, characterized in that the valve (14) cooperates with a seat (18) of diameter (d) less than the diameter (D) of a cylindrical compartment (15) in which it slides and which communicates with the spray nozzle (12).

3. Sprayer according to claim 2, characterized in that said cylindrical compartment (15) is provided with stop means (16) for stopping the valve in a predetermined position when the latter deviates from its seat (18).

4. Sprayer according to claim 3, characterized in that said stop means (16) define a stroke (h) of the valve such that h> d / 4, d being the diameter of the valve seat.

5. Sprayer according to any one of claims 2 to 4, characterized in that said cylindrical compartment (15) is coaxial with a hollow rod (10) of the piston (6) which opens into the chamber (5) to connect that -this at the nozzle (12).

6. Sprayer conforming to any of Claims 2 to 4, characterized in that said cylindrical compartment (15) is spaced from the axis of the piston (6) and communicates, through the valve (14), with a duct (23) provided in the wall of the chamber (5) to connect it to the nozzle (12).

7. Sprayer according to any one of claims 2 to 5, characterized in that the valve (14) is incorporated in the means (13; 21) of actuation of the piston (6), on the side thereof which is opposite to the one facing the pump chamber (5).

8. Sprayer according to claim 6, characterized in that the valve (14) and the nozzle (12) are fixed relative to the chamber (5).

9. Sprayer according to any one of claims 1 to 5, characterized in that the means

(20,21,22) for actuating the piston include a lever (21) manually actuated and arranged to amplify the force applied to it and transmit the amplified force to the piston (6).

10. Sprayer according to any one of claims 1 to 9, characterized in that the pressure of the liquid supplied to the nozzle remains substantially constant throughout the stroke of the piston (6) under the thrust of the actuating means (13; 20,21,22).