US3236458A

US3236458A - Aerosol apparatus

Info

Publication number: US3236458A
Application number: US258440A
Authority: US
Inventors: Ramis Jean
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-02-23
Filing date: 1963-02-14
Publication date: 1966-02-22
Anticipated expiration: 1983-02-22
Also published as: DE1616914A1; GB1006751A; US3369756A; FR1322998A; CH390814A

Description

Feb. 22, 1966 J. RAMIS 3,236,458

AEROSOL APPARATUS Filed Feb. 14, 1963 3 Sheets-Sheet 1 dear; Pam/s IN VE N TOR.

BY W

Attorney Feb. 22, 1966 J. RAMIS 3,236,458

AEROSOL APPARATUS Filed Feb. 14, 1963 3 Sheets-Sheet 2 Attorney Feb. 22, 1966 .s. RAMIS AEROSOL APPARATUS 3 Sheets-Sheet 5 Filed Feb. 14, 1963 Jean Ramls IN VE N TOR.

Attorney NNNN I i N N i N N United States Patent 3,236,458 AEROSOL APPARATUS Jean Ramis, Marly-le-Roi, Seine-et-Oise, France Filed Feb. 14, 1963, Ser. No. 258,440 Claims priority, application France, Feb. 23, 1962, 888,964 5 Claims. (Cl. 239-338) This invention relates to apparatus for the production of aerosols and more particularly to apparatus which will provide an aerosol dispersion in which the particles are of very uniform size and within required limitations of size.

Apparatus for the production of aerosols usually comprise a container charged with a propellant liquid and a substance intended to be discharged in aerosol condition, the container being provided with a triggerable discharge valve and nozzle connected to a tube passing down the vessel to terminate just short of its base. The vapor pressure above the liquid in the container thus forces it towards the valve and jet nozzle so that, on release of the valve the liquid rises to the valve where it vaporizes and is discharged.

In the case where the aerosol is required for therapeutic purposes in providing an inhalant, for example, the common form of aerosol-producing apparatus is not entirely satisfactory since the particles of the formed aerosol are not wholly within the desired limits of size. In fact, for such purposes it is desired that the particles of the therapeutic agent should be between 0.5 and 5 microns in size since particles above 5 microns may not reach the air-cells of the lungs while particles below 0.5 micron may fail to be deposited therein.

It is an object of the present invention to provide improved apparatus for the production of aerosols, particularly aerosols of therapeutic substances, which is adapted to yield aerosols whose particles are of very uniform size and substantially within the foregoing limits and which is of economical and compact design.

According to the present invention there is provided apparatus for the production of an aerosol dispersion which comprises a container for a propellant liquid and a substance which it is desired to discharge in aerosol condition, a triggerable discharge valve and nozzle unit for said container adapted, on actuation, to discharge the contents from the container in the form of a directional jet, and a tube extending forwardly of the nozzle opening substantially coaxially of the discharge jet, this tube being at least partially open at its rearward end (with respect to the nozzle) and providing a partial barrier to the free forward movement of the discharge jet.

In one form of the invention, the partial barrier or hindrance is provided in the form of one or more baflie plates disposed transversely to the axis of the tube and having finely polished surfaces facing towards the jet openings Such plates form a bafile or labyrinth which prevents the particles of the discharge jet from leaving the end of the tube in a straight line.

In this embodiment of the invention, the coarse particles of liquid emitted by the valve and traveling at a speed which is higher than that of the small particles strike the plates and break up into smaller particles which pass around the said plates at reduced speed, so that the discharged material leaves the end of the tube in the form of a homogeneous jet at low speed.

In another embodiment of the invention, the tube does not contain any internal solid bafile plates but is so dimensioned that the mass of air contained in the tube itself impedes the forward flow of the stream and serves as a barrier. Specifically, according to this embodiment the discharge aperture has a diameter of 0.1 to 0.3 mm., the

'ice

inside diameter of the tube is 10 to 40 mm. and preferably 18 to 30 mm. and its length is between three and ten times its diameter, preferably five to seven times.

With this embodiment it has experimentally been found that the jet emerging from the tube is again, as in the first case, a homogeneous jet whose diameter is equal to that of the tube and whose speed is substantially uniform across the crosssection of the tube.

A complete explanation of the behavior of the apparatus according to this second embodiment of the invention cannot be given with certainty, particularly because vaporization of the liquefied propellant gas results in thermodynamic effects. However, it is believed that the apparatus behaves as an ejector: by the transfer of momentum the jet entrains air inside the tube, but this transfer implies impacts, particularly between particles already dispersed in the air and particles contained in the jet, and this breaks up these particles, so that the composition of the jet leaving the tube is rendered homogeneous and the speed of the particles is substantially uniform across the whole cross-section of the emergent jet.- In other words, the physical obstacle in the form of bafiies in the first form of the invention is replaced by the obstacle comprising the flow resistance of the air contained in the open tube if this tube is sufiiciently long.

In specific forms of apparatus, according to the invention, where a tube without physical baflles is employed, the tube may be in two telescopically interfitting parts and be collapsible to form a housing for the container. In that case the tube part forming the inner member of the telescopic assembly may contain a head having a radial duct leading into a wall of this inner tube part, the outlet tube of the container being connected to that duct. Further, the tube part containing the head may be crowned by a cap rotatable through a limited angle to pass from a position in which the cap shuts off apertures formed in an end of this tube part, thereby blocking the inlet aperture to the radial duct in the head, and a position in which it opens these apertures.

Further, in all forms of the apparatus the nozzle unit may comprise a chamber in which the liquid to be discharged is rotated as it arrives tangentially to the chamber, the chamber being formed by two frusto-conical cavities having adjacent bases of the same diameter, one of these cavities being extended to form a short cylindrical outlet aperture.

The foregoing specific embodiments of the invention are referred to in more detail in the following description and will be described with reference to the accompanying drawing wherein:

FIG. 1 is a diagrammatic sectional View of one embodiment of the invention;

FIG. 2 is a diagrammatic sectional view of another embodiment of the invention;

FIG. 3 is a sectional view of a specific construction, according to the invention, in an inoperative position;

FIGS. 4a and 4b are sections on line IV-IV in FIG. 3, showing part of the apparatus of FIG. 3 in two different positions;

FIG. 5 is a sectional view of the device of FIG. 3, in an operative position;

FIG. 6 shows the apparatus of FIG. 3 in perspective; and

FIG. 7 is a perspective exploded view of the spray nozzle.

Throughout the several views, similar parts are similarly numbered.

In FIGS. 1 and 2, the containers 1 include tubes 2 leading to nozzle openings 5 through a conventional valve system (not shown) which is contained in the head 3 and can be operated by pressure exerted manually on the side lugs 4 of the head. Preferably, to obtain good spraying at the nozzle, the nozzle opening assembly is of the type creating a turbulent discharge jet; an embodiment of such an assembly is described hereinbelow. The valve used may be an ordinary valve or a metering valve of known type.

The pressure-resistant containers 1 contain a liquid 6 which, for example, includes dichloro-difluoro-methane, this propellant being known commercially as Freon 12, in which an active product is dissolved or kept in a homogeneous emulsional suspension.

The vapor pressure of dichloro-difiuoro methane at a temperature of 20 C. is approximately atmospheres. To obtain a more powerful discharge jet at the opening 5, an inert gas insoluble in the liquid 6, for example nitrogen, may be added to the gas atmosphere of the container.

In the embodiment shown in FIG. 1, a tube 8 is attached to the head 3 through the agency of a base 7 which is formed with air apertures 7a. This tube forms an expansion chamber around the jet opening 5 of the head 3. On the side opposite opening 5 this tube is partially closed by a ring shaped plate 9 and a discshaped plate 10, which is connected to the annular plate 9 by supports 11. The disc is offset towards the interior of the chamber with respect to the ring 9 and its diameter is substantially equal to that of the ring opening so that a stream of gas passing through the tube 8 cannot travel to the end of the tube in a straight line.

Thus, the particles leaving the orifice 5 are projected against the inner surface of the disc 10 where they break up. Moreover, turbulent movement is set up within the discharge jet and this results in homogenization of the discharge jet so that, as shown by the arrows, a homogeneous mixture of fine particles of gas and air leaves through the gap between the annular plate 9 and the disc plate 10 and escapes from the tube at a slow speed in the form of a homogeneous mist.

Preferably, the disc 10 has a slightly larger diameter than the section a of the conical discharge jet emerging from the opening 5 at the point where this jet makes contact with the disc. Moreover, the disc is preferably thickened at its center as shown to present a convex surface to the discharge jet, and is finely polished. In this way the risk of particles from the discharge jet being retained on the face of the disc may be minimized.

In the embodiment shown in FIG. 2, a tube 12 surrounding the stream leaving the nozzle opening 5 does not contain any solid internal obstacle. For an orifice of a diameter of about 0.2 mm., the diameter D of the tube is between 10 and 40 mm., and, preferably, for best results, between 18 and 30 mm. A diameter of 20 to 28 mm. has been found to be particularly suitable for most known therapeutic products.

Since the end of the tube 12 connected to the head 3 is very close to the orifice 5 the length L of this tube must be between 3 to 10 times the diameter D. However, lengths between 5 and 7 diameters give the best results. A relatively slow and homogeneous discharge jet, the particles of which are of sizes within the optimum limits, leaves at a uniform speed over the entire section of the tube from the aperture 12b as shown by the arrows.

The dimensions of the tube which is disposed around the discharge jet to provide the results indicated above are such that this tube is also suitable for use as a housing for the liquid container. Moreover, since this tube is relatively long, it may be advantageous to make it in a telescopic form so that it can be collapsed to smaller overall dimensions. 1

FIGS. 3 to 7 show such an embodiment of the invention. The tube is formed by two

elements

15 and 16 sliding one inside the other. To limit their relative displacement, the outer tube 15 has an internal peripheral bulge 15a and the inner tube 16 has an external peripheral 4. bulge 16a. These bulges abut (FIG. 5) when the syste is at maximum extension.

The inner tube 16 is closed by an end 18 formed with a central aperture 21 and peripheral apertures, one aperture 21) being in the form of a sector while the other aperatures 19 are circular (FIGS. 4a and 4b).

The extremity of the tube 16 carrying the end 18 is covered by a cap 22 of molded flexible material having the inside of its fiat wall formed with a central stud 23 which is received with a press fit in the aperture 21 so as to fix the cap in place; this flat wall also has apertures 24- of the same arrangement and distribution as the

apertures

19 and 20 in the end of the tube 16 and carries on its inner surface a lug 25 which engages in the aperture 29. Thus the cap 22 can turn on the tube 16 through an angle limited by abutment of the lug 25 against the two radial edges of the aperture 20, thus enabling the apertures 19 and 21} either to register with the apertures 24 or to be blocked by the solid parts of the flat wall of the cap when the latter is in a position of closure. A diametrically extending insert of head 27 is disposed within the tube 16 near the end 18 thereof.

The head is of cylindrical shape and is fitted by its ends in two diametrically opposite bores 28 and 29 of the tube 16 and is prevented from turning by a lug 30 engaging between projections 31 on the inner Wall of the tube 16.

On the inside, the head 27 contains a duct 32 discharging through a right-angle deflecting aperture 33 into a shouldered cup 34. Received Within cups 34, and bearing against its shoulder, is a stack formed by three elements of a nozzle unit shown in FIG. 7, namely a filter 35, a vortex-forming cylinder 36 and a plate 37 formed with a small vaporization aperture 38. The vortex cylinder 36 has a rear cavity 39 communicating through two wide opposite recesses 49 with the front surface of the cylinder. Slots 41 are formed on this front surface and lead tangentially in the same direction to the edge of the central frusto-conical cavity 42 of the front surface of the hollow cylinder 36. The cavity 42 co-operates with the rear frusto-conical end 43 of the aperture 38 (the two frustocone bases having the same diameter) to form a small chamber in which the liquid arriving through the filter 35, the cavity 39 and the channels 4-0 and 41 flows turbulently before leaving in the form of a fast conical jet through the aperture 38. It is well known that if this liquid is a liquefied prop-ellent gas associated with a liquid product for spraying, such as arrangement already gives a very fine spray.

The liquid to be sprayed is contained in a cylindrical receptacle 44, whose outer diameter corresponds to the inside diameter of the tube 16 so that it can be housed therein (FIG. 3). This container is provided with a valve (not shown) disposed in the fixing a mounting flange 45, this valve terminating in a hollow stem 46. The valve in flange 45 is preferably a conventional metering valve so that a limited quantity of liquid leaves the end of the valve stem 46 when this stem is pushed towards the interior of the container 44.

In the inoperative position (FIG. 3), the flange 45 engages a number of fine ribs 47 formed in the inner wall of the inner tube 16 so that the container forced inside the tube 16 is held there by resilient pressure. Excessive penetration of the container into the tube 16 is prevented by a shoulder 48 which meets the

endsof tubes

15 and 16 and which is of the same diameter as the outside tube 15 so that the outside surface of the nested assembly (FIG. 3) is substantially continuous.

The peripheral wall or skirt of cap 22 has a hole 49 which registers with the inlet to the duct 32 when the cap is in the position to open the apertures 19.

Upon the withdrawal of container 44 from the interior of the tubes, its outlet tube 46 can be engaged in the head 27 when the holes 19 in the end 18 of the tube 16 are freed by suitable orientation of the cap 22 with respect to that tube. In this position, the platform 50 of the cap is diametrically opposite the container 44.

When the tube has been pulled so that the system formed by the two tubes is at its maximum length, a homogeneous mist of fine drops leaves the free end of the tube 15 in the form of a vapor when pressure is applied to the platform 50; if the tube 15 is allowed to remain telescoped onto the tube 16 the spray is in the form of a fast moving non-homogeneous cloud.

In a practical construction of this apparatus the extended length of the

tubes

15 and 16 was 13 centimeters and their inside diameter 2 centimeters for an aperture 38 of diameter 0.18 mm.

I claim as my invention:

1. A device for producing an aerosol dispersion, comprising:

an elongated generally cylindrical tube open at one end and provided at its other end with a wall having at least one air hole and with a lateral inlet aperture next to said wall;

a cap rotatably engaging said other end, said cap having at least one port registering with said air hole in one rotary position, said cap having another rotary position completely blocking the passage of air through said wall, said cap being further provided with a peripheral skirt extending across said inlet aperture, said skirt having an opening registering with said inlet aperture in said one rotary position only;

a container for a substance to be dispensed along with a propellant therefor, said container having a generally cylindrical body fitting into the open end of said tube in an inoperative position, said container being provided with valve means including a tubular stem matingly receivable in said inlet aperture upon alignment thereof with said opening in said one rotary position of said cap, said valve means being triggerable for discharging a stream of particles from said container through said stem whereby said particles are radially injected into said tube by way of said inlet aperture;

and deflecting means for said stream disposed in said tube for directing said particles axially outwardly through said open end.

2. A device as defined in claim 1, further comprising co-operating abutment means on said tube and said cap for enabling relative rotation thereof between limits respectively corresponding to said one and said other rotary position.

3. A device for producing an aerosol dispersion, comprising:

an elongated generally cylindrical tube open at one end and provided at its other end with a wall having at least one air hole and with a pair of diametrically opposite lateral apertures next to said wall;

a cap rotatably engaging said other end, said cap having at least one port registering with said air hole in one rotary position, said cap having another rotary position completely blocking the passage of air through said wall, said cap being further provided with a peripheral skirt extending across said lateral apertures, said skirt having an opening registering with one of said apertures in said one rotary position l;

an insert extending diametrically through said tube at said other end, said insert having extremities received in said lateral apertures and being provided in one of said extremities with an inlet channel terminating at said one of said apertures for unblocking by said opening in said one rotary position of said cap, said inlet channel communicating with a central passage in said insert open toward said one end of said tube;

a container for a substance to be dispensed along with a propellant therefor, said container having a generally cylindrical body fitting into the open end of said tube in an inoperative position, said container being provided with valve means including a tubular stem matingly receivable in said inlet channel upon alignment thereof with said opening in said one rotary position of said cap, said valve means being triggerable for discharging a stream of particles from said container through said stem whereby said particles are radially injected into said tube by way of said inlet channel;

and deflecting means for said stream disposed in said insert at the junction of said channel with said passage for directing said particles axially outwardly through said open end.

4. A device as defined in claim 3 wherein said tube consists of an inner section and an outer section telescopically engaging each other, said inner section being provided with said insert and said cap, said outer section being slidable on said inner section between an extended position remote from said cap and a retracted position adjacent said cap, said body fitting into said inner section in the retracted position of said outer section.

5. A device as defined in claim 4 wherein said body is formed with a shoulder remote from said stem engageable with the open end of said tube for sealing same in said retracted position.

References Cited by the Examiner UNITED STATES PATENTS 2,890,697 6/1959 Van Sickle 239-337 2,940,641 6/1960 Norris et al. 239-337 3,006,340 10/1961 Meshberg 222394 3,012,555 12/1961 Mesh'berg 222-394 3,069,097 12/1962 Cheney 239-338 3,101,904 8/1963 Prussin et al 239--339 3,104,062 9/1963 Mahon 239338 3,107,670 10/1963 Silson et al 222394 FOREIGN PATENTS 868,785 5/1961 Great Britain.

M. HENSON WOOD, JR., Primary Examiner.

EVERETT W. KIRBY, Examiner.

Claims

1. A DEVICE FOR PRODUCING AN AEROSOL DISPERSION, COMPRISING: AN ELONGATED GENERALLY CYLINDRICAL TUBE OPEN AT ONE END AND PROVIDED AT ITS OTHER END WITH A WALL HAVING AT LEAST ONE AIR HOLE AND WITH A LATERAL INLET APERTURE NEXT TO SAID WALL; A CAP ROTATABLY ENGAGING SAID OTHER END, SAID CAP HAVING AT LEAST ONE PORT REGISTERING WITH SAID AIR HOLE IN ONE ROTARY POSITION, SAID CAP HAVING ANOTHER ROTARY POSITION COMPLETELY BLOCKING THE PASSAGE OF AIR THROUGH SAID WALL, SAID CAP BEING FURTHER PROVIDED WITH A PERIPHERAL SKIRT EXTENDING ACROSS SAID INLET APERTURE, SAID SKIRT HAVING AN OPENING REGISTERING WITH SAID INLET APERTURE IN SAID ONE ROTARY POSITION ONLY; A CONTAINER FOR A SUBSTANCE TO BE DISPENSED ALONG WITH A PROPELLANT THEREFOR, SAID CONTAINER HAVING A GENERALLY CYLINDRICAL BODY FITTING INTO THE OPEN END OF SAID TUBE IN AN INOPERATIVE POSITION, SAID CONTAINER BEING PROVIDED WITH VALVE MEANS INCLUDING A TUBULAR STEM MATINGLY RECEIVABLE IN SAID INLET APERTURE UPON ALIGNMENT THEREOF WITH SAID OPENING IN SAID ONE ROTARY POSITION OF SAID CAP, SAID VALVE MEANS BEING TRIGGERABLE FOR DISCHARGING A STREAM OF PARTICLES FROM SAID CONTAINER THROUGH SAID STEM WHEREBY SAID PARTICLES ARE RADIALLY INJECTED INTO SAID TUBE BY WAY OF SAID INLET APERTURE; AND DEFLECTING MEANS FOR SAID STREAM DISPOSED IN SAID TUBE FOR DIRECTING SAID PARTICLES AXIALLY OUTWARDLY THROUGH SAID OPEN END.