US 3097645 A
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July 16, 1963 v. E. LESTER 3,0 45
NEBULIZER Filed March 22. 1960 2 sheets-sheet 1 INVENTOR. 3o V/cro E LESTER V. E. LESTER NEBULIZER July 16, 1963 2 Sheets-Sheet 2.
Filed March 22. 1960 & 174
positioning of thenozzles.
United States Patent 3,097,645 NEBULIZER Victor E. Lester, R0. Box 608, Sonora, Calif. Filed Mar. 22, 1960, Ser. No. 16,776 14 Claims. ((31. 128-194) This invention relates to an improved liquid nebulizing device. More particularly, the invention relates to structurally simple, easy-to-manufacture nebulizer designed primarily for construction from plastic, a nebulizer which will uniformly convert a liquid into the proper aerosol for inhalation therapy, without clogging or other malfunctioning.
In the treatment of respiratory system disorders, inhalation of a therapeutic in aerosol form is a well-known and very satisfactory procedure. Fo instance, medicaments such as antihistamines, bronchodilators, vasconstrictors, and antibiotics, plus many others, are now commonly administered as an aerosol. An aerosol is a colloidal system of small particles of a solid, or droplets of a liquid, surrounded by and entrained in a gaseous medium. The success of this type of therapy depends greatly upon the formation of a proper aerosol, and the proper administration of it. If the particles or droplets of the medicament are too fine, they are not retained in the respiratory tract but are, to a great extent, exhaled. On the other hand, if they are too large, they will be deposited on the upper reaches of the respiratory system, such as the trachea and the upper tracheal-bronchial tree, leaving the rest of the system untreated. Likewise, if the aerosol is not-delivered to the patient in a smooth, uniform manner, the dosage may be either too large or too small. It is quitenecessary then, to control closely both the size of the medicament particles in the aerosol and the manner of its administration; only a properly designed nebulizer will do just that.
There are many glass nebulizers available, some of which perform their task satisfactorily. However, most of these nebulizers use the fly-spray principle of aero- -soliz-ation, which involves directing t-hestream of gas at right angles across the open end of a tube running to the liquid. Usuallya pair of small nozzles 'are used, one for the air and the other for the liquid; these are so positioned that just the right amount of liquid is entrained by the stream of gas. Manufacturing such a device involves several problem's, one of the largest of which is the precise Another problem is how to construct the nozzle orifices of just the correct size, since orifices either too large or too small-will result in an improper aerosol. Both of these problems, combined with other factors, result in a high manufacturing cost which in turn results in an expensive item'atthe consumer level.
Perhaps the greatest disadvantage of a glass-nebulizer isits susceptibility to breakage. Such a device is very delicate, especially where the nozzles are involved, and it must be handled with a great degree of care. All nebulizers must undergo periodic cleaning, and many glass parts, especially the veryhard-to-clean nozzles, are easily broken during this procedure.
'In an attempt to overcome some of the foregoing problems,-several plastic nebulizers have been made. These nebulizers also use the fly-spray principle of ofaerosolization, and the same problems of nozzle positioning, openings, and cleaning are present. Usually the nozzles are made separatelyand then cemented in "place, and as the cement dries the relative positions of the nozzles change. Consequently, each nebulizer must be tested to see that it produces the correct aerosol; this-testing procedure'adds substantially to the manufacturing. cost.
An additional problem encountered with a plastic nebulizer is the attraction of the plastic material for the droplets of medicament. Evenwhen asatisfactory aerosol is produced by correctly positioned nozzles in a plastic 2 nebulizer, some of the medicament strikes and clings to the plastic surfaces. This attraction is sometimes so great that within a few minutes the nebulizingaction of the nozzles is overcome and all the medicine is extracted from the aerosol. This, of course, cannot be condoned.
An important object of this invention is the provision of a plastic nebulizing device which will produce continuously a satisfactory therapeutic aerosol forsustained periods of time.
Another object of thisinvention is the provision of a relatively simple nebulizing device which can be constructed for a fractionof the cost of other nebulizing devices.
A further object of the invention is the provision of a relatively unbreakable nebulizer.
Another object of this invention is the provision of a nebulizer which can be easily and quickly cleaned, with a very minimum danger of breakage.
Still anotherobject of the invention is the provision of a novel nebulizer nozzle.
Other objects and advantages will appear in the following description of a preferred embodiment of the invention, set forth in accordancewith 35 UiS.C. 112.
.In the drawings:
FIG. 1 is a view in perspective of a nebulizer embodying the principles of this invention;
FIG. 2 is a view in side elevation and in-section of the nebulizer of FIG. 1;
FIG. 3 is a view in front elevationiand in section taken along the line 33 of FIG. 2;
FIG. .4 is an enlarged view in side elevation and in section of the lower portion of the .nebulizer of FIGS. 1-3, .takeualong the line 44 in FIG. 3;
FIG. 5 is a view in horizontal section. taken along the line 55 of FIG. 4; and
FIG. 6 is a top. plan view .of the nebulizerof'FIG. 1.
As illustrated in the drawings, the :nebulizer 10 generallycomprises a bowl 11,.a cover 12,. an aerosolexit tube 13, an inner ,air nozzle 14, an outer spraynozzlei15, and an air-hose attachment 16.
The Bowl 11 The 'bowl 11 is shaped somewhat like an invertedupper half of a pear, the lower portion of the bowl' narrowing down and the upper portion broadening out. This unique shape plays an important part in the performance of the nebulizer; the liquid medicament 17 occupies but asmall fraction of the total volume of the nebulizer, and the remaining volume, which is devoted toserving as acontain- .er for the aerosol, is large enough to overcome .the attractive action of plastic material for the droplets of medicament. This means that the nebulizer will continue to produce asmooth, uniform aerosol for as long as there is sufficient liquid medicament 17. No stoppage occurs, as in prior. devices, and the patient receives the proper. dosage, at the proper rate,.without interruption.
The Cover 12 The cover 12 has a shape tofit onto the top of the b-owl'Il and continue the contour of the bowl smoothly around to the aerosol eXit tube 13. The cover 12 preferably has a filling spout 20 adapted to receive. a closure device, such as a plug -21, for introducing liquid into the bowl 11 or emptying any leftover liquid. However, if desired, this filling spout 2.0 may be omitted and filling and emptying may be accomplished easily through the tube :13. Also, the filling spout 20'. may be located elsewhere, if desired.
The Aerosol Exit .Tubel3 The aerosol exit tube 13 is comprised of an inner section '22 which is integral with the coverIZ and an outer, separate section 23. The lower surface 24 of the inner section 22 serves as a bafile to catch the oversize droplets of liquid and return them to the bowl 11. The outer section 23 may be adapted to fit into a conventional inhalation mask or other device for attaching the unit to the patient; or may be used as a mouthpiece by merely inserting it into the mouth of the patient. The configuration of the outer section 23, therefore, is not critical, and may take any form so long as it performs its intended function.
The Spray Nozzle 15 Extending upwardly on the inside of the bowl 11 from its lower end is a slightly tapered, tubular spray nozzle 15, preferably formed integrally with the bowl 11. This spray nozzle 15 curves inwardly at its upper end to form an annular flange 25 with a centrally positioned, round spray orifice 26. At the lower end of the spray nozzle 15 is a series of liquid inlets 27, equally spaced around the base of the nozzle 15, and communicating with the bowl 11 so that the liquid 17 may flow unrestricted into the inside of the nozzle 15.
In determining the diameter of the spray orifice 26, consideration must be given to the rate of gas flow through the nebulizer and the viscosity of the liquid 17 to be nebulized. When used with a gas flow of between about two to eight liters per minute (as measured on a Bourdontype gauge calibrated against a No. 77 drill orifice, i.e., 6 to 18 lbs./in. and a thin liquid with a viscosity approximately that of water, a spray orifice 26 having a diameter within the range of about 0.030 and 0.045 inch produces a satisfactory aerosol; a diameter of about 0.035 inch gives optimum results. If the gas flow rate is extended outside this range, and/or a more viscous liquid is used, then compensation should be made in the diameter of the spray orifice 26 to obtain the desired aerosolization. By this procedure the nebulizer easily may be adapted to substantially any combination of gas flow rate and liquid viscosity.
The size of the liquid inlets 27 are not as critical. Substantially any opening which will permit suflicient flow of liquid 17 from the bowl 11 into the inside of the spray nozzle 15, to maintain a constant full supply of liquid at the top of the air nozzle 14, will suflice.
The Air Nozzle 14 The air nozzle 14 preferably is formed separately from the rest of the nebulizer and inserted into the inside of the spray nozzle 15, where it is cemented in place. This air nozzle 14 also is slightly tapered from bottom to top, to conform with the taper of the spray nozzle :15, and terminates at its upper end in an annular flange 28 having a centrally positioned round air orifice 29. In their correct positions, the nozzles 14 and 15, and the orifices 29 and 26, are coaxial.
The air nozzle 14 serves as an inlet for the carrier gas, such as compressed air or oxygen, and therefore is connected via a flexible hose 30 or some other suitable means to the source of this gas. A bulbous-type connector 31, or other suitable device, aids in securing the hose 30 to the air nozzle 14.
A shoulder 32 of the nozzle 14 is preferably proportioned to seat upon the lower end of the bowl 11, for positioning the nozzle '14 and firmly supporting it in its correct relationship to the spray nozzle 15. As depicted in the drawings, the shoulder 32 is relatively wide and, consequently, gives sturdy, firm support. This results in a very strong union of parts-in fact, one which is practically indestructible and so substantially eliminates the danger of nozzle fracture commonly encountered with other nebulizing devices.
As with the spray orifice 26, there is a relationship between the diameter of the air orifice 29, the gas flow rate, and the viscosity of the liquid 17. Based upon a gas flow of from two to eight liters per minute (as measured on a Bourdon-type gauge calibrated against a No. 77
drill orifice, i.e., 6 to 18 lbs./in. and a thin liquid with a Water-like viscosity, the diameter of the air orifice 29 should be between about 0.020 and 0.025 inch, with about 0.023 inch giving optimum results. Where gas flow rates outside of this range are used, and/or more viscous liquids are to be nebulized, the diameter of the air orifice 29 should be altered to that providing the desired results.
Most therapeutic liquids designed for inhalation therapy have a water-like viscosity, and may be aerosolized satisfactorily with a nebulizer '10 having a spray orifice 26 with a diameter of about 0.035 inch, and an air orifice 29 with a diameter of about 0.023 inch. Proper modification of these diameters, in accordance with the invention, to accommodate other viscosities and flow rates, depends upon the particular viscosity-flow rate combination, and will become apparent to the practioner. Therefore, no attempt will be made to set forth an elaborate table of various orifice sizes for the multitude of possible combinations of viscosities and flow rates operable in this invention.
Along with the foregoing relationships, for satisfactory results the distance D (see FIG. 4) between the inside surface 33 of the end 25 of the spray nozzle 15 and the outside surface 34 of the end 28 of the air nozzle 14 should be between about 0.012 and 0.015 inch, Where the diameter of the spray orifice 26 is between about 0.030 and 0.045 inch, and the diameter of the air orifice 29 is between about 0.020 and 0.025 inch. If this distance D is greater than about 0.015 inch percolation rather than nebu lization results, and large droplets are produced instead of a fine aerosol.
As stated above, the inner section 22 of the aerosol exit-tube 13 lies directly above the nozzles 14 and 15 and in operation its lower surface 24 acts as a battle, separating from the aerosol stream emanating from the orifice 26 the coarser drops, so that only a fine aerosol flows around the end 35 of this section 22 to the patient. The large droplets that strike this battle either drop back into the liquid 17 or adhere to the surface of the baffle and migrate across the cover 12 and down the bowl 11 to join the reservoir of liquid 17. The length of the section 22 is not critical but, in all cases, should extend substantially beyond a point directly above the nozzles 14 and 15 so that it prevents any oversize droplets from escaping.
Operation In operation, the device is filled to just below the top of nozzle 14 with a liquid therapeutic. An air bulb (not shown), or any other suitable source of compressed air, oxygen, or other desired gaseous fluid carrier is connected to the nozzle 14 by a suitable conduit 30, such as a flexible hose, and the outer end of the section 23 of the tube 13 is attached to a mask covering the patients face, or inserted directly into the patients mouth.
As the gas courses upwardly through the nozzle 14, it exits through the orifice 29 and creates a partial vacuum in a space 36 between the nozzles 14 and 15. This vacuum causes the level of the liquid therapeutic 17 between the nozzles 14 and 15 to rise and flow over the top of the nozzle 14. When the stream of gas strikes this liquid, it entrains it in droplet form and carries it along through the orifice 26 in an upward direction, striking the broad bottom surface 24 of the tube section 22. Any oversize droplets of liquid are removed and the proper size droplets migrate around the end 35 of the tube section 22 to continue on into the patients respiratory tract. Since the bottom portion of the bowl 11 tapers down to a narrow confine, substantially all of the liquid therapeutic is used before replenishing is necessary.
Construction and Assembly Because of their shape, the various parts of this nebulizer may be quickly and easily injection-molded, without the need for extensive additional machining. Many of the nozzlesin prior nebulizers require elaborate procedures to form their outlet orifices. These problems are not present in this invention, for the orifices Hand 26 are accurately molded in place.
Assembly-wise, since the spray nozzle 15is molded integrally with the bowl 11, its position is established at the outset. When the air nozzle 14 is inserted into the spray ,nozzle 15, the broad mounting-shoulder 32 securely and properly positions the nozzle 14. The use of a'small amount of adhesive or other plastic joining material quickly and securely unites all the parts into one durable unit.
Both solutions of therapeutic and suspensions in-a liquid may be satisfactorily nebulized in the nebulizer 10, with the proper combination of spray orifice 26, air orifice 29, and distance D. Thus this highly versatile unit may be used for all liquids in the realm of inhalation therapy.
Not only may this nebulizer be made of plastic, but it also may be constructed of glass, if preferred, with equally satisfactory results. When made of plastic, this nebulizer is considerably less breakable, and the problem of the attraction of the plastic for the liquid is completely over come. Among the various plastics which are suitable for use, crystal polystyrene has been found to be highly satisfactory. It is very durable, easy to clean, has a nice clear appearance, and is easily shaped and assembled. There are many other compositions on the market which are satisfactory materials for making this device, and they will be readily apparent to those who care to practice .the invention. Therefore, no attempt is made to enumerate them.
Many of the nebulizers preceding this invention have had another disadvantage in that, if tipped or otherwise not held precisely in a limited operating position, the liquid either would pour :out or would be sufiiciently displaced from proper position so that the nebulizing action would cease. The unique shapes of the bowl 11,:and the cover 12 have overcome each. of these problems. Only by tilting the bowl 11 to an extreme degree, sothat the liquid inlets 27 are exposed, will the nebulizing action be impaired. Also, the liquid will not flow out of the unit unless it is turned upside-down and the outer end or the tube section 23 dropped. These features enable the device to be used safely under various conditions where some tilting and agitation of the unit is encountered, and yet uninterrupted treatment must be maintained.
To thoseskilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.
1. A nebulizer, comprising: a covered bowl-like liquid container; an atomizing nozzle assembly comprising an inner tubular air-nozzle extending up generally vertically through the bottom of the bowl to a point inside said container and above the bottom thereof and an outer tubular spray-nozzle inside said container concentric with and spaced from said air nozzle, said spray-nozzle having liquid inlet means near its lower end by which liquid from said container can enter, and both said air-nozzle and said spray-nozzle having orifices at their upper ends; and a relatively large, generally horizontal tubular outlet means for nebulized material spaced from said nozzle assembly such that a stream of nebulized material emanating from said nozzle assembly impinges the wall of said outlet means before it enters said outlet means, said outlet means having an opening leading from said container into said outlet means.
2. A nebulizer, comprising: a covered bowl-like liquid container; an atomizing nozzle assembly comprising a straight inner tubular air-nozzle extending up through the bottom of the bowl into the interiorof said container and to a locus above said bottom and a generally coaxial outer tubular spray-nozzle inside said container concentric with and spaced from said air-nozzle, said spray-nozzle having liquid inlet means near its lower end by which liquid from said container can enter, both said air-nozzle and said spray-nozzle having coaxial orifices at their upper ends; an elongated outlet passageway for nebulized material spaced from said nozzle orifices, with the centerline of said passageway disposed generally perpendicular to the axis of said nozzles, said passageway positioned in the path of the stream of nebulized material emanating from said nozzle assembly to serve as a bafile to prevent oversize droplets of liquid from escaping from said container into said outlet passageway.
3. A nebulizer, comprising: a covered bowl-like liquid container; an atomizing nozzle assembly comprising an inner tubular gas-nozzle extending into the interior of said bowl above the lower end thereof and an outer tubular spray-nozzle surrounding said gas-nozzle and spaced from it, said spray-nozzle having liquid inlet means connecting its interior with a liquid-holding portion of said container, bothsaid air-nozzle and said spray-nozzle having orifices at their upper ends; and a relatively large aerosol outlet tube spaced from said nozzle assembly and athwart the path of the aerosol emanating from said nozzle assembly, said outlet tube thus serving as a'bafile to prevent oversize droplets of liquid from escaping from the ne-bulizer.
4. A nebulizer, comprising: an enclosed container adapted to hold a quantity of liquid; an atomizing nozzle assembly comprising an inner tubular air-nozzle extending through the bottom of the container into the interior of said container at a level above the bottom thereof and an outer tubular spray-nozzle coaxial and concentric with the portion of the said air-nozzle inside of the said container, said spray-nozzle having bottom liquid inlet means connecting to the said container, and both said air-nozzle and said spray-nozzle having an upper orifice, the orifices being in line with each other and having diameters matched to produce a fine aerosol from a liquid and a stream of gas; and a relatively large, tubular outlet for the aerosol spaced from said nozzle assembly and'with its axis substantially at right angles to the axes of said sprayand air-nozzles, said aerosol outlet positioned in the path of the aerosol stream from said nozzles and with intake means oft center with respect to said orifices, said aerosol outlet thus serving as a baffle to prevent oversize droplets of liquid from escaping from the nebulizer.
5.. A nebulizer, comprising: a bowl for holding a quantity of liquid; a cover enclosing the. top of the said bowl; a tube-like air-nozzle extending into the interior of said bowl and joined'intermediate its ends to the bottom of said bowl, said air-nozzle having an orifice at its inner end; a tube-like spray-nozzle enclosing the portion of the said air-nozzle lying inside of the said bowl and spaced apart therefrom, the said spray-nozzle being integral with the bottom of said bowl, having spaced liquid inlet ports around its lower end, and a spray orifice centrally located at its upper end, coaxial with the said air orifice of the said air-nozzle; and an [aerosol-outlet tube extending through the said cover, spaced from the said nozzles, and with its axis substantially perpendicular to the axes of the said nozzles, the said aerosol-outlet positioned in the path of the spray from said nozzles and thus forming a bafile plate against which the spray emanating from the said nozzles strikes.
6. The device of claim 5, wherein the cover is provided with a filling spout and a plug therefor.
7. The device of claim 5, wherein the air orifice has a diameter of between about .020 inch to .025 inch, the spray orifice has a diameter of between about .030 inch to .045 inch, and the distance between the ends of the said airand spray-nozzles is between about .012 inch and .015 inch.
8. A nebulizer, comprising: a bowl, shaped substantially as an inverted pear, adapted to hold a quantity of liquid; a substantially dome-shaped cover for said bowl; an upright, tubular air-nozzle with an inner section and an outer section, extending into the bowl through its bottom and joined intermediate its ends to the bottom of the bowl; an upright, tubular spray-nozzle, formed as an integral upward extension of the bottom of the bowl, spaced from yet enclosing the said inner section of the air-nozzle and coaxial therewith, said spray-nozzle having an inside diameter greater than the outside diameter of said air-nozzle, and having liquid inlet means through the bottom of its wall; an inwardly projecting annular flange at the upper end of said air-nozzle, integral therewith, forming an axially positioned round air orifice having a diameter of between about 0.20 and 0.25 inch; an inwardly projecting annular flange at the upper end of said spray-nozzle, integral therewith, forming an axially positioned round spray orifice having a diameter of between about .030 and .045 inch, the inner surface of the said spray-nozzle annular flange being positioned between about .012 and 0.15 inch from the outer surface of the said air-nozzle annular flange; a relatively large, tubular outlet for the nebulized liquid having an inner section and an outer section, said outlet extending through one side of the said cover, with its axis at right angles to the axes of the said sprayand air-nozzles, and with its inner section spaced from the said nozzles but athwart the path of the stream emanating from said nozzle orifices, the said inner section of the said outlet tube thereby acting .as a battle to prevent oversize droplets of liquid from escaping from the nebulizer.
9. The device of claim 8, wherein the diameter of the air orifice is about .023 inch, the diameter of the spray orifice is about .035 inch, and the distance between the inner surface of the spray-nozzle annular flange and the outer surface of the air-nozzle annular flange is about .012 inch.
10. A nebulizing nozzle assembly comprising: an inner, tubular air-nozzle; an outer, tubular liquid-nozzle coaxially enclosing said inner air-nozzle but spaced apart therefrom; an inwardly projecting annular flange at one end of said air-nozzle, integral therewith, forming an axially disposed round air orifice having a diameter of between about .020 and .025 inch; an inwardly projecting annular flange at the corresponding end of said liquid-nozzle, integral therewith, forming an axially disposed round spray orifice having a diameter of between about .030 and .045 inch, the inner surface of the said liquid-nozzle annular flange positioned between about .012 and .015 inch from the outer surface of the said airnozzle annular flange; and liquid inlet means in the other end of the said liquid-nozzle.
11. The nozzle assembly of claim 10 wherein the diameter of the air orifice is about .023 inch, the diameter of the spray orifice is about .035 inch, and the distance between the said inner surface of the said spray-nozzle annular flange and the said outer surface of the said airnozzle annular flange is about .012 inch.
12. A nozzle assembly for use in a nebulizer comprising: an inner, generally straight tubular lair-nozzle with an end wall having an unobstructed small central orifice therethrough; an outer, generally straight tubular spray-nozzle having liquid inlet means and an end wall with an unobstructed small central orifice somewhat larger than said orifice of said air nozzle, said spraynozzle being coaxial with and enclosing said air-nozzle and being spaced apart therefrom both radially and axially, with said liquid inlet means leading between them, said end walls of said nozzles being closer together than the diameter of said spray-nozzle orifice.
13. A nozzle assembly for use in a nebulizer comprising: an inner, generally straight tubular air-nozzle extending vertically and having a lower air inlet and an upper end wall with an unobstructed small central orifice therethrough; an outer, generally straight tubular spray-nozzle extending vertically and having liquid inlet means at its lower end and an upper end wall with an unobstructed small central orifice somewhat larger than said orifice of said air nozzle, said outer spray nozzle being coaxial with and enclosing said inner air-nozzle and being spaced apart therefrom both radially and axially for liquid passage from said liquid inlet and so that the vertical distance between the end walls of said nozzles is less than the diameter of said spray-nozzle orifice.
14. A nozzle assembly for use in a nebulizer comprising: an inner, tubular air-nozzle; an outer, tubular spraynozzle coaxial with and enclosing said air-nozzle and spaced apart therefrom; an inwardly projecting annular flange at the discharge end of said air-nozzle, with a small axial unobstructed air orifice; an inwardly projecting annular flange at the corresponding end of said spraynozzle, with a small axial unobstructed spray orifice slightly larger than said air orifice, the distance between the inner surface of the said spray-nozzle annular flange and the outer surface of the said air-nozzle annular flange being smaller than the diameter of said spray-nozzle orifice, with the orifice sizes and said distance thereby being so related that a fine aerosol is produced when the device is operated.
References Cited in the file of this patent UNITED STATES PATENTS 2,406,997 Curry Sept. 3, 1942 2,432,660 Curry Dec. 16, 1947 2,726,896 McKinnon Dec. 13, 1955