Atomizers

Abstract

A liquid atomizer comprises a first cylinder containing a hollow, first piston, an atomizing nozzle communicating with the hollow piston a second cylinder of smaller cross-section than the first and communicating therewith. A second piston is slidable in the second cylinder and valve means connected to the second piston serve to block communication between the hollow piston and the nozzle. First and second springs are provided which respectively bias the valve means to close off the communication with the nozzle and lie between the two cylinders to bias them apart.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention.

This invention relates to liquid atomizers, particularly of perfume.

2. Description of the Prior Art.

A liquid atomizer has been proposed comprising a first cylinder in which a hollow piston is slidably mounted connected to an atomization tube, a second cylinder of smaller section than the first, which communicates with the first cylinder and in which is slidably mounted a piston connected to a valve suitable for interrupting communication between the first cylinder and the atomization tube, and resilient means acting on the second piston and biasing the valve into the position in which the said communication is interrupted, the assembly of the two cylinders defining a space which communicates with a plunger tube through a non-return valve.

In this prior proposal, when the first piston is moved, it carries with it the second piston through the intermediary of the valve, but the available space for liquid decreases, since the second piston has a section which is smaller than that of the first. The pressure of the liquid in the two cylinders increases so that the second piston tends to move with respect to the first against the action of resilient means which act on it. When this pressure reaches a sufficient value to balance this action, the second piston moves whilst carrying with it the valve connected with it so that the cylinders are put in communication with the atomization tube. The liquid contained in the cylinders is thus only atomized when its pressure reaches a predetermined value, which avoids the production of non-atomized drops, which phenomena would occur if the cylinders were placed in communication with the tube from the start of the movement of the first piston. Similarly on the termination of the movement of the first piston, the valve interrupting communication between the cylinders and the tube when the liquid pressure exerts on the second piston a force lower than the return force of the resilient means.

The atomizers of the type hereinbefore outlined, have the disadvantage of difficult priming since the delivery pressure increases progressively as the hollow piston is plunged downwardly. Moreover, the atomizer must include a valve preventing return to the liquid reservoir which is provided in the first cylinder; this inlet valve is generally carried by the small piston and is thus movable with respect to the casing of the pump. It has been established that when the delivery valve leaves its blocking position, the inlet valve has a tendency to leave its seat, which causes return to the reservoir of a certain amount of liquid contained in the first cylinder; the loss of pressure which follows this spoils atomization.

The object of the present invention in an improvement in atomizers of the hereinbefore described type, which enables ready priming of the atomizer.

SUMMARY OF THE INVENTION

According to the present invention, there is provided in a liquid atomizer, a first cylinder, a hollow, first, piston slidable in the first cylinder, an atomizing nozzle communicating with the hollow piston, a second cylinder of smaller cross-section than the first cylinder and communicating with the first cylinder, a second piston slidable in the second cylinder, valve means connected to the second piston and disposed to interrupt communication between the first cylinder and the nozzle, a first spring acting on the second piston and biasing the valve means to a position in which the said communication is interrupted, a non-return valve, a plunger tube communicating with a space defined by the two cylinders through the non-return valve, the second cylinder being disposed within the first piston and being movable with respect to the first cylinder, and a second spring acting to bias the two cylinders apart.

This construction overcomes at least partially the difficulties of previously proposed atomizers, the spring interposed between the two cylinders ensuring release of fluid with a pressure of a constant predetermined value. Furthermore, the advantage arises of increasing the volume ejected by a given stroke of the larger piston.

In one preferred embodiment of the invention in which the atomization tube is connected by an axial tube to the first piston, this axial tube comprises a part of reduced internal diameter which defines a seat and the second piston is connected to a rod which is slidably mounted in the tube and of which the end forms the delivery valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal, part-sectional view of an atomizer in accordance with the invention;

FIG. 2 is a longitudinal section, to an enlarged scale, of a part of the atomizer of FIG. 1;

FIG. 3 is a section on the line III--III of FIG. 2; and

FIG. 4 is a view in section of a part of the atomizer of FIG. 1 at the end of the stroke of a push-button thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As is illustrated in the drawings, the atomizer in accordance with the invention comprises a cylinder 1 which has in a lower part thereof a flange 1a and is secured to an internally-tapped bush 2 intended to close-off a receiver containing the liquid to be atomized. This cylinder 1 communicates, at its lower part, with a plunger tube 3 through a non-return valve 4.

In the cylinder 1 there is slidably mounted a hollow piston 5 secured to one of the ends of a tube 6; the other end of this tube is secured to a push-button 7 which comprises an atomization tube or nozzle 8 in communication with the said tube 6. The portion of the piston 5 slidably mounted in the cylinder 1 is frusto-conical and is connected through a shoulder 5a to the portion of the said piston which is fixed to the tube 6. This latter portion is cylindrical and is itself slidably mounted with a predetermined clearance, in a casing 9 fitted in the cylinder against the edge of which the shoulder 5a can just come into abutment. In the hollow piston 5 a blind bushing 10 is slidably mounted which is closed at its end directed towards the non-return valve 4. A spring 11 is interposed between this bushing and the bottom of the cylinder 1; it biases the bushing 10 against the end of the tube 6 and also the piston 5 against the cover 9. Lateral passages 12 are formed in the internal face of the hollow piston 5 or, as shown, in the external face of the bushing 10 and openings 10a formed in the internal end of this bushing, put the cylinder 1 in communication with the interior of the bushing 10. The latter forms a cylinder of smaller cross-section than the cylinder 1, in which is slidably mounted a piston 13 dividing the interior of the cylinder 10 into two chambers 14 and 15.

The piston 15 is rigid with a rod 16 which is disposed in the tube 6 and of which the end 16a forms a valve capable of being applied against a seat 6a formed in the tube 6 and constituting a restriction of this tube, so as to interrupt communication between the chamber 14 of the cylinder 10 and the nozzle 8. A spring 17 interposed between the bottom of the cylinder 10 and the piston 13 biases the valve 16a to seat on its seat 6a.

A hole 18 is formed in the cylinder 1, substantially at the height of the upper edge of the cover 9; this hole opens into the interior of the bushing 2, and thus to the interior of the receptacle containing the liquid to be atomized. The lateral wall of the cylinder 10 has a hole 19 opening into the chamber 15. This hole 19 lies opposite a hole 20 of the piston 5 and thus puts the chamber 15 in communication with the receptacle through the hole 18. Finally, the wall of the cylinder 1 comprises an annular recess 1a upstream of the position occupied by the end of the piston 5, at the end of the stroke of the latter. When the atomizer is inoperative, the various parts occupy the position shown in FIG. 1. It is totally fluid-tight since the valve 16a is biased against its seat by the spring 17 and the shoulder 5a is biased against the end of the cover by the spring 11.

The atomizer operates in the following manner. Initially, the cylinder 1 and the chamber 14 contain air. The user presses on the push-button 7 as indicated by the arrow f. This push-button drives the piston which compresses the air in the cylinder 1. At the end of its stroke, the piston arrives opposite the recess 1a (FIG. 4) so that the air compressed in the cylinder can escape to the exterior through the clearance space 21 existing between the internal wall of the cylinder and the piston, because of the frusto-conical form of the latter. Then, when the user releases the push-button, the piston 5 returns and again abuts against the internal wall of the cylinder 1, in such a manner that a depression is generated in the cylinder and causes the liquid to rise through the plunger tube 3. At the end of two or three operations, the cylinder 1 and the chamber 14 are full of liquid to be atomized.

During the operation of the push-button 7, the piston 5 compresses the liquid contained in the cylinder 1 as well as that in the chamber 14. When the pressure attains a predetermined value, balancing the action of the spring 17, the piston 13 moves within the cylinder 10 whilst carrying with it the rod 16. The valve 16a moves away from its seat 6a so that the pre-compressed liquid passes through the nozzle 8 which effects its atomization.

The displacement of the piston 5 follows, the liquid contained in the chamber 1 is returned to the nozzle 8 through bores 12, the chamber 14 and the tube 6.

On completion of the movement, when the piston 5 arrives opposite the recess 1a, the pressure in the chamber 14 falls rapidly, in such a manner that the spring returns the valve 16a to its closed position; the liquid which can pass through the clearance 21 returns to the reservoir through the orifice 18. Then, when the user releases the push-button 7, the spring 11 returns the piston 5 and the members which are connected to it to their initial positions, that it to say the cylinder 10, the piston 13, the tube 6 and the rod 16. The assembly has then taken up again the position of FIG. 1 and a depression of pressure is thus generated in the cylinder 1. As the valve 16a is held against its seat, liquid is aspirated into this chamber through the plunger tube 3 and the non-return valve 4.

It will be apparent from the description which is given hereinbefore that the liquid is atomized under a minimal pressure, depending on the force of the spring 17 and that the atomization ceases when the pressure becomes lower than the minimal pressure. The atomization is thus effected always under good conditions so that liquid drops cannot form.

When the piston 5 is being displaced, the internal part of the receptacle is put in communication with the atmosphere through the orifice 18 and the clearance between the casing 9 and the piston 5. The air can thus enter the receptacle in order to compensate for the volume of liquid which is transferred from this receptacle into the cylinder 1 when the piston 5 rises again.

In the case where the liquid gains access to the chamber 15 via the rims of the piston 13 and the wall of the cylinder 10, this liquid returns into the receptacle through the holes 19 and 20.

It will be clear that the present invention should not be considered to be limited to the embodiment described and shown but covers, on the contrary, all modifications within the scope of the appended claims. Thus, in particular, the piston 5 and the tube 6 may be formed of a single part only.

Claims

I claim:

1. In a liquid atomizer,

a first cylinder,

a hollow, first, piston slidable in the first cylinder,

an atomizing nozzle communicating with the hollow piston,

a second cylinder of smaller cross-section than the first cylinder and communicating with the first cylinder,

a second piston slidable in the second cylinder,

valve means connected to the second piston and disposed to interrupt communication between the first cylinder and the nozzle,

a first spring acting on the second piston and biasing the valve means to a position in which the said communication is interrupted,

a non-return valve,

a plunger tube communicating with a space defined by the two cylinders through the non-return valve,

the second cylinder being disposed within the first piston and being movable with respect to the first cylinder, and

a second spring acting to bias the two cylinders apart.

2. An atomizer according to claim 1, further comprising a receptacle containing the liquid to be atomized, said first cylinder having an orifice communicating with the receptacle.

3. An atomizer according to claim 1 wherein the hollow, first, piston is externally of frusto-conical form, at least over an end portion directed towards the bottom of the first cylinder.

4. An atomizer according to claim 1, wherein the wall of the second cylinder has at least one opening providing communication between the interior of the second cylinder and the interior of the first cylinder.

5. An atomizer according to claim 1, wherein the internal face of the first piston has at least one opening providing communication between the interior of the second cylinder and the interior of the first cylinder.

6. An atomizer according to claim 1, comprising a tube affording communication between the interior of the first piston and the nozzle, said tube comprising a part of reduced diameter which defines a seat forming one portion of said valve means, the other portion of said valve means comprising a rod connected to the second piston slidably mounted on said tube and the end of which co-operates with said seat.

7. An atomizer according to claim 2, wherein the second cylinder has opposite the second piston a discharge orifice aligned with an orifice formed in the first piston and communicating with the receptacle containing the liquid to be atomized.