US3036781A - Atomizer - Google Patents

Description

States The present invention relates to atomizers, more particularly though not limitatively, to pocket atomizers of the general type described by our copending patent application Serial No. 802,907, filed March 30, 1959, now Patent 2,974,879, which comprise essentially a casing including a liquid reservoir and a pump chamber, a piston movable within said chamber, an air discharge passage terminating in a spraying opening or orifice and connecting said chamber with the outside atmosphere, and a liquid discharge nozzle connected with said reservoir through a feeding tube or conduit and terminating in said passage, whereby displacement of said piston within said chamber causes liquid to be withdrawn from said chamber by and to be mixed with the air-stream passing or being forced through said passage, to result in a liquid spray or mist being discharged from said orifice.

Liquid dispensing devices of this type are especially suitable as pocket atomizers for use in connection with perfumes, disinfectants, medicinal preparations and the like liquids on account of the efiiciency of the pumping effect, which among other advantages, makes it possible to construct devices in relatively small size and for the discharge of limited liquid quantities, substantially without impairment of the operating safety and reliability.

With pocket atomizers of this and related types, difficulties have been experienced in the past in rendering the devices sufficiently leakproof in practically all positions, without the use of auxiliary means, such as a rotary cover or the like closure device. In the case of the abovementioned application, leakage is prevented principally by a reduction of the discharge orifice or nozzle of the feeding tube extending to the bottom of the reservoir, in such a manner that liquid may be withdrawn only upon the production of an effective partial vacuum or suction effect in the neighborhood of the discharge nozzle by the airstream during operation of the piston in the air or pump chamber.

If, in such a case, only a small quantity of liquid is left in the reservoir, that is, if the reservoir contains a relatively large amount of air, and if furthermore the temperature of the atomizer rises suddenly, such as by removing it from a cold room and placing it in the pocket of a garment worn by the user, the air pressure in the reservoir will be increased accordingly and may attain a sufiicient value to cause a liquid discharge through the nozzle or orifice. Such a condition is highly undesirable on account of the loss of liquid and contamination of the device, as well as for other reasons well understood.

Accordingly, an important object of the present invention is to overcome the foregoing and related difficulties and drawbacks inherent in pocket atomizers of the type mentioned, by substantially preventing a liquid discharge due to pressure variations in the reservoir, such as caused by ambient temperature fluctuations.

Another object of the invention is to limit the liquid discharge in an atomizer of the type mentioned to conditions of an adequate partial vacuum created in the neighborhood of the discharge nozzle or orifice by the airstream during operation of the piston, while substantially preventing a discharge due to increased air pressure in the liquid reservoir, such as caused by an ambient temperature rise.

Yet another object of the invention is the provision atent ice of an atomizer of the above type which may be used or stored in any desired position, substantially without the danger of leakage caused by ambient temperature changes and a resultant air pressure rise in the reservoir.

With the foregoing and other objects in view, as will become more apparent hereafter, the invention contemplates principally the combination with a pocket atomizer embodying a liquid feeding tube or conduit arranged with one end thereof near the bottom of the reservoir and with its opposite end terminating in a discharge nozzle or orifice extending into the airstream produced by operation of the piston in the pump chamber, of a capillary, venting tube connecting the air space of the liquid reservoir with the outside atmosphere, said capillary for this purpose being so arranged or mounted within the reservoir that the inner end thereof is positioned at the geometrical center of said reservoir. As a result, if the amount of liquid in the reservoir is maintained below an upper limit equal to about one half of the total volume or liquid level, the orifice or inner end of the capillary will always be above the liquid level, or within the air space of the reservoir substantially independently of the position of the atomizer during use or storage. If now a pressure rise occurs in thereservoir, such as caused by a sudden increase of the ambient temperature, this pressure will be instantly and readily equalized with the outside or ambient air pressure directly through the capillary and without involving any loss or leakage of liquid.

In the operation of the atomizer of this type, a slight vacuum is created in the reservoir at the end of the compression stroke of the piston in order to replace the sprayed amount of fluid, this being practically negligible and equalized, in the case of the afore-mentioned patent application, during the ensuing suction or return stroke of the piston, through the feeding tube and discharge nozzle. This equalization of the internal air pressure, in the case of the present invention, also occurs through said capillary, substantially instantly and during the operation of the piston.

According to an improved feature of the invention, the inside diameter of the capillary, or at least of the inner end thereof, is made less than, such as about equal to one half of, the inside diameter of the orifice of the liquid feeding tube or discharge nozzle. By this expedient, the safety against leakage of liquid may be further increased. Even with the diameter of the capillary being equal to the diameter of the discharge orifice of the feeding tube pressure equalization will normally occur through the capillary for the reasons pointed out. Furthermore, since the feeding tube is always at least partly filled with liquid, independently of the position of the atomizer and since, furthermore, the liquid possesses a certain viscosity, while the capillary is filled with air, the pressure equalization will take the path of least resistance, that is, by way of the capillary, so much as the pressure variations in practice are of a rather slow or gradual nature. This safety factor may be further improved by the diiferential between the diameters of the capillary and discharge orifice, in the manner described hereinabove.

I The feeding tube may be advantageously provided with an angular extension adjacent to the bottom of the reser- The suction opening of the feeding tube is advantageously positioned adjacent to the bottom or wall of the reservoir, whereby even slight liquid residues may be withdrawn by suitably canting the atomizer. For this purpose, it may be advantageous to construct the reservoir of transparent material.

The invention, both as to its further objects and novel aspects, will be better understood from the following detailed description of a preferred practical embodiment taken in conjunction with the accompanying drawing forming part of this specification with the single view thereof representing a vertical cross-section on an enlarged scale of the improved pocket atomizer.

Referring more particularly to the drawing, the atomizer according to the present invention may comprise a stationary part being constituted, in the example shown, by a liquid chamber or container 1, a center piece or pump chamber 2 and a closure ring or cylinder 3. The container 1 includes a reservoir 4 which is hermetically closed by the bottom 5 of the center piece 2. The container and the center piece may be connected in any suitable manner, such as a screw, glue or the like joint or connection. The bottom 5 of the center piece 2 has a central recess 6 which may serve as an abutment for one end of a conical return spring 7 the opposite end of which engages the sleeve or lower part 8a of a hollow piston 8 movable within the chamber 2. The recess 6 is connected with the outside atmosphere through a horizontal bore or passage 9 terminating in a spray orifice or opening 10. Arranged at right angle 10 and terminating in the passage 9 is a nozzle 11 forming the end of a liquid feeding or riser tube 12 mounted in the reservoir 4.

The piston 8 is arranged to slide or move within the center piece or chamber 2 forming a pump cylinder, such as by the construction of the sleeve or part 8a to form an annular sealing lip or ring 13. The piston 8 includes a central coaxial part or member having a bore or recess 14 wherein is mounted a check valve 15, having a chamber enclosed by the piston and the part 8a, in the manner shown. As a consequence, the check valve which may be in the form of a simple flap valve mounted underneath the bore 14 will be operated by the displacement of the piston 8 within the chamber 2, in a manner understood and further described hereafter. The bore 14 is connected with the intermediate chamber 17 within the piston through a vent opening 16, while the chamber 17 is, in turn, in communication with the outside atmosphere through an opening 18 in the outer wall of the piston. In the drawing, the openings 16 and 18 are shown aligned with one another. It is understood, however, that they may be relatively displaced, to suit any existing conditions and requirements.

The underside of the piston 8 above the sealing lip 13 is formed with a shoulder 19 which in the expanded position of the spring 7, as shown in the drawing, engages a corresponding shoulder 20 of the closure ring 3 or center piece 2, respectively, to fix the upper limit position of the piston and to prevent the same to be ejected from the chamber or cylinder 2.

Mounted upon the bottom 21 of the reservoir 4 or integral with the liquid container 1 is a capillary venting tube 22 the inner end 23 of which is located at the geometrical center of the reservoir, that is, about halfway from the bottom upon the axial center line in the case of a cylindrical reservoir, as shown by the drawing. Furthermore, in the example shown, the feeding tube 12 has a bent 27 adjacent to the bottom 21 and extends diametrically to the opposite wall of the reservoir as shown at 24, in such a manner that the suction or ingress opening of the tube is located near the bottom 21 and adjacent to the side wall of the reservoir, to enable a minimal liquid rest to be withdrawn from the reservoir.

As described in greater detail in the abovementioned copending application, the airstream being forced through the passage 9, upon depression of the piston 8 against the action of the spring 7, results in liquid being sucked or withdrawn through the nozzle 11 and to be discharged through the orifice 10 in the form of a liquid spray or mist. The slight partial vacuum produced thereby in the airspace of the reservoir 4 will be equalized instantly through the capillary 22 connecting the reservoir with the outside atmosphere.

If an excess air pressure should occur in the reservoir 4 due to any cause, such as by a temperature rise or heating of the atomizer, the gas pressure in the reservoir will be relieved substantially instantly or equalized with the outside pressure through the capillary 22, independently of the position of the atomizer during use or storage, provided the reservoir has been initially filled to slightly less than one half, to ensure the inner end 23 of the capillary to be located in the air space or above the liquid level in all positions of the reservoir or atomizer.

Due to the fact that feeding tube 12 contains a substantially greater amount of liquid than may be discharged by a number of operating strokes of the piston 8, an adequate amount of liquid will be contained in the tube under all conditions, whereby the equalization of the air pressure in the reservoir will be caused to take the path of lesser resistance through the capillary 22 rather than through the tube 12 and nozzle 11. This effect may be further increased by constructing the inner end 23 of the capillary 22 to have a lesser diameter than the discharge nozzle 11 at the end of the tube 12. The liquid content of the feeding tube is further increased by the horizontal or bent portion 24 adjacent to the bottom 21.

According to a further improvement, the feeding tube may be provided with a restricted portion located advantageously within the bend or angular member 27 and shown at 26 in the drawing. For this purpose, the bent may be in the form of an intermediate or angle piece to which are secured the two portions 12 and 24 of the tube. Alternatively, the bent may be a part of one of the tubes and contain the restricted portion 26, as shown in the drawing. In any case, it is essential that the restricted portion 26 be adjacent to the end of the tube and it has been found advantageous to construct the tube with two parts and an intermediate angular member including the restricted passage, in the manner shown by the drawing.

The provision of the restricted passage 26 results in a further increase of the safety against liquid leakage, without substantially reducing the volume or liquid content of the tube. The capillary or restricted portion 26 preferably has an inside diameter slightly less than one half of the inside diameter of the discharge nozzle 11. As an example, for a diameter of 0.5 mm. of the nozzle 11, the diameter of the restriction 26 may be about 0.24 mm.

In the foregoing, the invention has been described with reference to a specific illustrative device. It will be evident, however, that modifications and variations, as well as the substitution of equivalent parts or elements for those shown for illustration, may be made without departing from the broader scope and spirit of the invention as set forth in the appended claims. The specification and drawing are accordingly to be regarded in an illustrative rather than in a restrictive sense.

We claim:

1. In an atomizer of the type comprising a casing including a liquid reservoir and a pump chamber, a piston movable within said chamber, an air discharge passage connecting said chamber with the outside atmosphere and a liquid discharge nozzle connected to said reservoir and terminating in said passage, whereby to withdraw liquid from said reservoir by the airstream forced through said passage upon displacement of said piston, the improvement consisting in the provision of a capillary venting tube conmeeting said reservoir with the outside atmosphere, said tube extending into and terminating at the geometrical center of said reservoir.

2. In an atomizer as claimed in claim 1, at least the inner end of said tube having an inside diameter being less than the inside diameter of said nozzle.

3. In an atomizer of the type comprising an oblong casing having a separating wall, to provide a liquid reservoir and a pump chamber, a piston movable within said chamber, an air discharge passage Within said wall connecting said chamber with the outside atmosphere, a liquid discharge nozzle terminating in said passage, and a feeding tube extending from said nozzle to the bottom of said reservoir opposite to said wall, whereby to withdraw liquid from said reservoir by the airstream forced through said passage upon displacement of said piston Within said chamber, the improvement consisting in the provision of a capillary venting tube connecting said reservoir with the outside atmosphere, said tube extending from the center of said bottom into and terminating at the geometrical center of said reservoir.

4. In an atomizer as claimed in claim 3 including an intermediate restricted portion within said feeding tube.

5. In an atomizer as claimed in claim 4, the inside diameter of said restricted portion being slightly less than one half of the inside diameter of said discharge nozzle.

6. In an atomizer as claimed in claim 3, the inner end of said venting tube having an inside diameter less than the inside diameter of said discharge nozzle, and an angular extension connected to the lower end of said feeding tube through a passageway of reduced cross-section, compared with the cross-section of said tube, and extending across the bottom of said reservoir.

References Cited in the file of this patent UNITED STATES PATENTS

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