US 2826454 A
Description (OCR text may contain errors)
March 11, 1958 H. COANDA 2,826,454
ATOMIZERS Filed May 7, 1954 Unite States Patent 2,826,454 ATOMIZERS Henri Coanda, Paris, France, assignor to Sebac Nouvelle S. A., Lausanne, Switzerland, a corporation of Switzerland Application May 7, 1954, Serial No. 428,334
Claims priority, application France April 14, 1949 7 Claims. (Cl. 299-885) The present invention relates to atomizers for producing a fog or cloud of small particles of a liquid suspended in a gas. The atomizer in accordance with the invention is particularly suitable for producing a fog or cloud of particles of a liquid having therapeutic or remedial characteristics intended to be inhaled by a patient. However, it will be apparent that the atomizer can also be used for other purposes.
It is an object of the present invention to provide an atomizer that is of simple construction and yet is particularly efficieut and effective in producing a fog or cloud of extremely small particles of a liquid. By reason of their small size, the particles of liquid remain suspended in the air for a long period of time and their effectiveness for therapeutic or other uses is increased by reason of, the extremely fine subdivision.
It has been found that when a stream of fluid flows along a boundary surface which continually diverges from the initial direction of the fluid flow, either sharply or gradually, the stream follows the boundary surface with increasing velocity and induces surrounding fluid to join the stream. In accordance with the invention, this phenomenon, which is known as the Coanda effect, is utilized to obtain high velocity without the need of high pressure and to obtain extremely fine division of a liquid being atomized.
The nature and characteristics of atomizers in accordance with the invention and the principles upon which they work will be more fully understood from the following description and claims and from the accompanying drawings which illustrate by way of example a preferred embodiment of the invention and in which:
Fig. l is a vertical sectional view of an atomizer in accordance with the invention, including an atomizing head which is shown in elevation.
Fig. 2 is a vertical axial section on a larger scale of the atomizer head.
Fig. 3 is a further enlargement of a portion of Fig. 2 to illustrate more clearly the structure providing the above. mentioned Coanda efifect.
The atomizer shown by way of example in the drawings comprises a chamber or envelope 1 formed of glass or other suitable material and having a generally tubular form. At its upper end, the envelope 1 is tapered in to provide a flue 2 through which a cloud or fog of fine particles of the atomized material will issue into the atmosphere. Below the envelope 1, there is a receptacle 3 having a generally conical form. The receptacle 3 is removably secured to the lower end of the envelope 1, for example by means of a plurality of spring clips 4 which engage cooperating annular flanges provided at the lower end of the envelope 1 and the upper edge of the receptacle 3, respectively. An annular gasket or packing 4a is preferably provided between the flanges of the envelope and receptacle to serve as a cushioning means and provide a fluidtight joint.
An atomizing head H is positioned in the power portion of the envelope 1 and is coaxial with the envelope.
ment therewith so as to be in the path ofwtllejet 0f A tube 5 extends downwardly from the atomizing head H into the receptacle 3 so that the lower end of the tube 5 is near the bottom of the receptacle and hence dips into liquid 6 that is to be atomized and has been poured into the receptacle 3. At the upper end of the tube 5, there is provided an upwardly converging nozzle 7 which is suitably secured to the tube 5, for example by soldering or brazing, and has a threaded neck portion 7a that is screwed into an internally threaded hollow body 8. The lower portion of the nozzle 7 is surrounded by a knurled collar 22 which is shown secured to the nozzle by one or more set screws 21. The knurled ring 22 provides a convenient means for adjustably screwing the nozzle into the hollow body portion 8. While the nozzle 7 and ring 22 can, if desired, be made integral, it is preferred to make them in two parts, as shown, so that the nozzle 7 is interchangeable with other like nozzles that may be made of different materials, according to the liquid to. be atomized. For example, the nozzle 7 may be made of stainless steel in certain cases.
A pipe 9, which is adapted to be connected to a supply of fluid under pressure, for example compressed air, extends through a cork 23 in an aperture 24 of the envelope 1 and the inner end of the pipe is secured into a radial hole in the hollow body 8. The pipe 9 opens into an annular space or passageway 10 in the hollow body 8 surrounding an upper reduced portion of the nozzle 7. A dilfuser 11 is screwed into an axial bore in the hollow body 8 in axial alignment with the nozzle 7, the lower end of the diffuser 11 being spaced from the upper end of the nozzle 7 so as to provide an annular slot 12 opening into the annular passage 10. By screwing the diffuser 11 and/or the nozzle 7 into or out of the hollow body 8, the width of the annular slot 12 can be adjusted as desired.
The difiuser 11 has an axial bore with an upwardly convergent inlet end portion 11a, a restricted throat por-- section (Fig. 3) continually diverges, or curves away from, a line A-A which may be referred to as the axis of the slot 12 and represents the initial direction of the stream of air as it enters the slot 12 from the annular passage 10. By reason of the above mentioned Coanda efiect, the stream of air entering the annular slot 12 from the passage 10 follows the surface of the lip 11a and hence continually changes its direction, diverging more and more from the initial direction A--A. This results in an increase in the veloctiy of the air stream and also results in inducing fluid from the nozzle 7 to join in the air stream passing upwardly through the diffuser 11. Liquid from the receptacle 3 is thereby drawn up through the tube 5 and the nozzle 7. By reason of the high velocity of the air as it flows around the lip 11a of the annular slot 12 and through the throat 11b of the diffuser 11, liquid entering the air stream from the nozzle 7 is broken up into very small particles and diffused through the air. The diffusion is increased by the upwardly divergent portion of the dilfuser. The applicant has made the surprising observation that air, evenunder relatively low pressures, attains a very high speed.
A downwardly opening semi-spherical cup 15is posi-fl tioned above the atomizing head H and in axial alignand fine liquid particles 14 issuing from the diffuser 11. The cup 15 is supported by a threaded rod 16 screwed intoa threaded eye 16a in a support 20 that extends in through a rubber stopper 17 in a lateral aperture 18 of the envelope 1. In striking against the cup 15, the particles or droplets of liquid are broken up still further and are subdivided to exceptional fineness. Any droplets that may not have been atomized sufficiently in the diffuser are deflected by the cup 15 and return to the receptacle 3. The cup 15 is spaced away from the atomizer head H a distance more than the radius of the cup so that any droplets deflected by the cup are not picked up again by the stream of air from the atomizer head. The distance from the cup to the atomizer head is adjustable by means of the threaded rod 16. A cloud or fog of extremely fine particles with any larger droplets thus removed flows upwardly and issues fromthe outlet flue 2- into the atmosphere.
The cup 15 is formed of metal, glass or other suitable material and may, if desired, be coated with extracts from plants or from the organs of animals such as the liver, the glands, etc. enriched by vitamins and having a therapeutic or beneficial effect. The cup may also'be made from, or coated with, elemental substances such as magnesium, calcium, lithium, silver or iodine.
The apparatus is suitably supported, for example by legs 19 and a ring 19a surrounding the envelope 1.
It is understood that the embodiment illustrated in the drawings is shown and described by way of example and that it may undergo various improvements or modifications, as will be recognized by those skilled in theart, without departing from the spirit of the invention.
This application is a continuation in part of my copending application Serial No. 155,337, filed April 11, 1950,. now abandoned What I claim and desire to secure by Letters-Patent is:
1. In an atomizer, means defining a chamber, the lower portion of said chamber providing a liquid receptacle, an upwardly directed nozzle having a discharge end disposed above said receptacle, a'throat having an upwardly convergent throat disposed aboveand coaxially with said nozzle, the minimum inside diameter of said throat being approximately equal that of said nozzle and the lower end'of said throat being slightly spaced from the discharge end of said nozzle, means defining an annular slot surrounding the discharge end of said nozzle and merging with the space between said nozzle and said throatljthe wall of saidconvergent throat portion diverging from the axis'of said slot,-means definingat least one supply passage connecting the nozzle with said receptacle and means defining at least one-supply passage connecting said annular slot with a source of gas pressure, and an inverted cup-shaped member-disposed above said throat on an axis coaxial with saidthroat and with the axis of said chamber, the lower edge of said cup-shaped member being disposed wholly above the upper end of said throat.
2. In an atomizer, means defining a chamber, the lower portion of said chamber providing a liquid receptacle, said chambe'r'havinga discharge opening in itsupper portion, an upwardly directed diffuser above said receptacle, said difluser having an upwardly convergent inlet end portion, a restricted throat portion and an upwardly divergent disc-har-geend portion, a nozzle having a discharge end coaxial :with and spaced from the inlet end of said diffuser,- thespace between said nozzle and diffuser providing an annular slot, means defining an annular passageway communicating withsaid slot, means for connecting said-passageway with a source of fluid under pressure and means connecting said liquid receptacle with said nozzle, thelower end of said slot extending below the discharge end of said nozzle and the walls of said slot having a lesser slope than said throat/one of the walls of said slot as seen in axial section, continually diverging irom a-straightline-drawn in the direction of the inlet portion-of said slot and defining the axis of said slot, whereby a stream of said fluid flowing over said wall increases in velocity and induces liquid from said nozzle to join said stream.
3. In an atomizer, means defining a chamber having a discharge opening in its upper portion, the lower portion of said chamber providing a liquid receptacle, an upwardly directed difiuser above said receptacle, said diflflfi?! having an upwardly convergent inlet end portion, a restricted throat portion and an upwardly di vergent discharge end portion, a nozzle having a discharge end coaxial with and spaced from the inlet end of said diffuser, the space between said nozzle and diffuser providing an annular slot, means defining an annular passageway communicating with said slot, the lower end of said lslot extending below the discharge end of said nozzle, and the walls of said slot having a lesser slope t ha n said throat, connections from .said passageway to a snpply of fluid underpressure and a conduit extending downwardly from said nozzle into said liquid receptacle, the upper wall of said slot, as seen in axial t n ent nuqusl di er ing om, a Straight lin.e drawn in the direction of the inlet portion of said slot from said p ewa and me ngv n c t n r i inlet p tion of said diffuser and defining the axis of said slot, so that a stream of flnid flowing inwardly from said passageway flows over said wall with an increasing velocity nd indg q l u dtrem sa dnqz le t9 i n i s d t e 1 apa zer e p sl g o ski 3, a d n a ly penin g pidispe ed QM e t ca x abo sa dd ine; as in ve t a a i nm n there ith aid u being ed t n i iditfuse a di t a e atle ste to t radius of said cup. 1 g
. 5.- nan at m ze m ansdefin a ham er having a di h r e o enin in it upper portign, t Q I P t of a het Pw d us liquid re ta le n upwardly directed difiuser above'said receptacle, said f r hay g an u wa ly con n nl t e d o tion, a restrictedthroat portion and an upwardly divergent discharge end portion, a nozzle having an outwardly tapered discharge end coaxial with and spacedfrorn the inlet end of said diffuser, the space between said nozzle and diffuser providing an annular slot merging with the throat of said difiuser, means defining an annular passageway surrounding .said slot and communicating therewith, the lower end of saidslot extending below the dis-' charge end of said nozzle, and the wallsof said slot having a lesser slope than said throat, connections from said passageway to a supply of gas under pressure and connections from said nozzle to a supply of liquid to be atomized, the upper wall ofsaid slot, as seen in axial section, continuously diverging from the direction of flow of gas into said slot from saidpassageway along the axis of said slot and merging into the converging inlet portion of .saiddifinser. so that said gas flowing over said well i lnesses-in. e i an e b induces liquid fromsaid nozzle to join said gas.
6, An atomizer according to claim 5, in which said s a slop s i war l d'up a y- 7, Anatornizer according to claim 5, a downwardly opening cup disposed above said dififuser and in alignmentt'herewithsaid cup being coaxial with the axis of said chamber and being spaced irom said diffuser a distance at least equal to the radius of said cup.
References Cited in the file of this patent UNITED STATES. PATENTS 750,351 Doyle Jan. 26, 1904 13042556 Holland;- .Oct. 29, 1912 1,263,079 Leon Apr. 16, 1918 1,748,004 Urquhart Feb. 18, 1930 2,224,605 Miller Dec. 10, 1940 1 FQREIGNPATENTS amass France 1. Jan. 24, 1924