Nebulizer
BRIEF SUMMARY OF INVENTION 
     In many kinds of lung disease it is necessary to deliver to the alveoli a small amount of medication or moisture. For example, in cystic fibrosis, asthma, and chronic obstructive pulmonary disease, thick phlegm in the lungs must be expelled, and this is assisted by thinning the phlegm with medication or moisture, delivered as a mist. 
     One form of therapy for doing this is by use of intermittent positive pressure breathing apparatus, which generally requires hospitalization and skilled attention. Where the condition is not extremely severe, it is possible to use nebulizers, which entrain the medication or moisture in a stream of air or oxygen to produce a mist which is breathed in by the patient under ambient pressure conditions. This is especially desirable for elderly or child patients, who often cannot tolerate pressure breathing. 
     The instant invention relates to a simple nebulizer of the ambient pressure type, wherein the medication or moisture is entrained in a modest current of air, supplied by a compressor, or oxygen, supplied by an oxygen cylinder. 
     The nebulizer is of relatively small size, so that it can be held in the palm of the patient&#39;s hand, with the unit-dose vial of medicine or moisture enclosed. Thus the patient can hold the device much as a smoker holds a pipe, and can readily raise the mouthpiece to his lips. This renders the device ideal for out-patient home use. The flow of gas needed to entrain the medication or moisture, in a particular embodiment on which the instant drawings are based, is a modest 6 to 8 liters per minute. In said embodiment, the medication or moisture in the small vial, holding 3-5cc of pure or medicated water, will be entrained in the flowing gas at a reasonably uniform rate for 10 to 15 minutes before being exhausted, and this length of time is convenient for treatment. 
     The 6 to 8 liters per minute of oxygen or air can be readily supplied from a conventional medical-oxygen cylinder, holding 250 cubic feet (over 9000 liters). Thus such a standard cylinder can be used for many treatments, in view of the small demand of oxygen. 
     The use of unit-dosage vial, the small size of the device, and the modest demand on oxygen, is advantageous for self-treatment by an out-patient. 
     In order to reduce costs, the basic nebulizer is built up of three injection molded parts. 
     An adapter connects the nebulizer to the patient&#39;s mouth for inhalation. The adapter includes a by-pass hold which can readily and selectively be blocked by the patient&#39;s finger to control mist concentration. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF DRAWINGS 
     FIG. 1 is a side view of the noval nebulizer, with a unit-dose hermetically sealed capped vial situated below. 
     FIG. 2 is a front view, corresponding to FIG. 1 of the nebulizer and the unit-dose vial. The vial is shown with cap torn off, situated below the nebulizer, ready for insertion. 
     FIG. 3 is a side view, partly in cross-section, taken along the plane 3--3 of the nebulizer of FIG. 2, with the unit-dose vial inserted, and showing how the device is held by the patient. 
     FIG. 4 is a cross-section, taken along the plane 4--4 of FIG. 3. 
     FIG. 5 is a partially exploded view of the nebulizer of the preceding figures. 
     FIGS. 6A, 6B, 6C and 6D are respectively side and front cross-sections taken along the planes 6A--6A and 6B--6B of FIG. 6C, a top view and a bottom view of the upper body of the nebulizer. 
     FIGS. 7A, 7B and 7C are respectively a front view, a cross-sectional view taken along the plane 7B--7B of FIG. 7A and a bottom view of the venturi of the nebulizer, while FIG. 7D is an enlarged cross-sectional view of the critical portion of the venturi. 
     FIGS. 8A and 8B are respectively side and front views taken along the planes 8A--8A and 8B--8B of FIG. 8C, while FIG. 8C is a bottom view of the lower body of the nebulizer. 
     FIG. 9 is a side view, in cross-section, showing in detail how the parts of FIGS. 6 to 8 fit together and how a unit-dose vial is combined therewith. 
    
    
     DETAILED DESCRIPTION 
     As shown in FIGS. 1 and 2, the nebulizer 10 comprises an upper body 60 and a lower body and vial holder 80. 
     An inlet tube 61 is an integral part of the upper body 60 and is adapted to be connected to a source of gas, such as air or medical oxygen, which flows into the inlet tube 61 at a moderate rate. 
     The flowing gas passes through the nozzle of a venturi unit, not shown in FIGS. 1 or 2, which sucks up liquid contained in a body 16 of a unit-dose vial 15, and entrains some of that liquid in the flowing gas as a mist. 
     The mist thereby produced flows up through the upper body 60 into an elbow 11 to a mouthpiece 12, which the patient puts into his mouth to inhale the mist. 
     The unit-dose vial 15 may be a hermetically sealed plastic blow-molded container, which contains the liquid (which may be pure sterile water or a medicine). It is contemplated that the container is filled while still within the blow mold and before a cap 17 is formed and sealed. Since the blowing of a container from the plastic parison occurs at temperatures far above the boiling point of water, the inside of the unit-dose vial 15 and its sterile filling will continue to remain sterile after discharge from the blow-molding and filling machine. 
     For use, the cap 17 of the unit-dose vial 15 is removed from the body 16 by breaking it away. To assist in readily removing the cap 17, the plastic between cap 17 and body 16 is thin and presents a plane of weakness, making it easy to tear off the cap. The body 16 of unit-dose vial 15 is then inserted into the lower body 80, as shown by the dotted lines of FIG. 1, so that a dip tube 93 will be adjacent the bottom of the body 16. The lower body 80 has cut-outs 81 which permit the sides of the body 16 of the unit-dose vial 15 to be grasped while the body 16 is being inserted into position. After the body 16 of unit-dose vial 15 is seated, a pliable sleeve 14 (FIG. 5) may be slipped over the main body 80 and the part of the lower body 80 below the inlet tube 61. This sleeve protects the body 16 of the unit-dose vial 15 from being disturbed by jostling, so that the body 16 remains in placing during use. Prior to use and set up of the device of the present invention, the sleeve is previously affixed to protect the lower extremity of the device. 
     FIG. 3 illustrates the manner of use of the nebulizer. It is held in the hand, much in the manner in which a smoker holds a pipe, and the mouthpiece 12 is placed in the lips. The patient breathes in through the mouthpiece 12 to receive the mist. 
     The elbow 11 has an opening 19 which is normally uncovered, so that as the patient inhales, air is drawn in through opening 19. A typical flow of gas into the inlet tube 61 is 6 to 8 liters per minute. This is less than a person normally breathes. Therefore, if the patient inhales only through the mouthpiece 12, additional air is breathed in through the opening 19. If the opening 19 is partially or completely blocked, as shown in FIG. 3 by the dotted finger, then less external air can be mixed inside the nebulizer, the concentration of the mist received by the patient is higher. Thus, whenever the patient feels the need for a higher concentration of mist, the need is filled by abstructing the opening 19 by a slight movement of the finger. 
     The construction of the upper body 60 of the nebulizer 10 is shown in greater detail in FIGS. 6A to 6D. The upper body is injection molded of ABS or another suitable thermoplastic material. A two part mold, having a side entry core, is used to mold the upper body. The parting plane between the two parts of the mold is depicted in FIG. 6A. It will be seen in FIG. 6A that the surfaces of the upper body are provided with a draft (i.e., a taper) to permit the upper mold to be withdrawn upwardly from the parting plane and to permit the lower mold to be similarly withdrawn downwardly. Furthermore, the interior of inlet tube 61 is provided with a draft to permit the core which forms the interior to be withdrawn towards the left. No similar draft is needed for the outside of inlet tube 61 because the outside is molded by the upper and lower molds, which do not withdraw sidwardly. The elbow 62 is provided with a strengthening web 63. 
     The venturi 70 which forms the mist is shown in detail in FIGS. 7A to 7D. This part is injection molded to precision standards from nylon or some other thermoplastic material which will hold close tolerances. The part is molded in a two-piece die having separate cores for the bores 71, 72 and 73 (FIG. 7B). The parting plane for the two parts of the die is shown in FIG. 7A. 
     As can be seen from FIGS. 7A to 7B, the bores 71 and 73 have a draft to permit withdrawal of the cores by which they are molded. The bore 72 also has a suitable taper, too small to be depicted in the drawing. The outer surface 74 of the portion forming bore 71 need not be similarly tapered since the molds which form the outer surface 74 do not withdraw upwardly. The outer surface 77 of the portion forming the bore 73 is tapered, not because of a mold-release problem, but to save material. 
     The exterior surface 74 fits the bore 64 of the upper body when venturi 70 is united with the upper body 60. Thus, bore 71 receives the flow of gas which comes from inlet tube 61, by way of flow through elbow 62. The rib 75, as is known in the art, serves to help establish a leak-proof connection between elbow 62 and bore 71. 
     The lower end of the venturi 70 is adapted to be extended with a dip tube 93, as can be seen in FIG. 9. The dip tube 93 is made of ABS or another suitable thermoplastic material, rather than of nylon, in order to reduce the size and cost of the expensive precision molding seen in FIG. 7B. The dip tube 93 is cemented to the bore 73 by first depositing a small amount of cement in recess 79, inserting the upper end of dip tube 93 in the bore 73, and then rotating the dip tube with respect to the bore 73 to distribute the cement about the outer periphery of the portion of dip tube 93 adjacent recess 79. 
     In operation, the flow of gas into inlet tube 61 through elbow 62 is directed to nozzle 76 and forms a gas jet past the bore 72. As is understood in the art, the rapid flow of gas past the outer end of bore 72 reduces the air pressure thereat because of the Bernoulli effect. If the lower end of the dip tube 93 is immersed in fluid contained in the body 16 of a unit-dose vial 15, some of the fluid will be sucked up into bore 73 and on up to bore 72 and out into the gas jet. The miniscus of liquid, which forms at the outer end of bore 72 is disturbed and torn by the gas jet from nozzle 76, thereby entraining globules of moisture of various sizes in the gas jet. The gas jet hits a knob 78 and is deflected. During this deflection, the smaller globules of moisture are carried along with the deflected gas jet, while the larger ones are not carried along with the deflected gas jet but instead impinge on knob 78. The knob 78,therefore, acts as a separator for trapping the larger globules while permitting the smaller globules to be carried along as a mist. The differing sizes of globules are affected differently because as the size of a globule varies, the sail-area varies as the square of the diameter while the inertia-mass varies as the cube of the diameter. 
     While a venturi such as disclosed will operate over a wide variation of design, the relationship depicted in FIG. 7D optimizes operation. It will be noted that the bore 72 protrudes into the gas jet an amount slightly past the center line of the jet. Furthermore, the flat plane surrounding the outer end of bore 72 is tilted slightly so as to be relieved at the downstream side, with respect to the gas jet. For a gas flow of 6 to 8 liters per minute, the following parameters provide very satisfactory operation: 
     
         ______________________________________                                    
Diameter of bore 76     0.025&#34;                                            
Diameter of bore 72     0.036&#34;                                            
Diameter of tilted flat                                                   
plane                   0.050&#34;                                            
Radius of spherical outer                                                 
surface of water nozzle 0.062&#34;                                            
Distance, bottom of 76 to                                                 
center line of 72       0.056&#34;                                            
Linear offset           0.004&#34;                                            
Angular clearance       1.5°                                       
______________________________________                                    
 
    
     The lower body and vial holder 80 is shown in detail in FIGS. 8A to 8C. The upper end of the lower body 80 is adapted to be united with the lower end of the upper body, as can be seen in FIG. 9. Lower body includes a funnel 82 and a coupling 83. The funnel 82 collects the drip of larger globules of moisture from the upper body 60 (principally from the knob 78) and delivers this moisture to coupling 83, which feeds it to the body 16 of the unit-dose vial. 
     Thus, excess moisture which is not delivered to the mouth-piece 12 recycled back to the vial. Furthermore, the outer side of coupling 83 is tapered, to snugly fit the opening in the body 16 of the unit-dose vial. 
     Thus, excess moisture which is not delivered to the mouth-piece 12 is recycled back to the vial. Furthermore, the outer side of coupling 83 is tapered, to snugly fit the opening in the body 16 of the unit-dose vial. The snug fit prevents leakage of moisture from the body 16 of the unit-dose vial, in the event the patient shakes the nebulizer 10. The ribs 84 seen in FIG. 8C help to frictionally retain the body 16 of the unit-dose vial in operative position with the dip tube 93 and funnel 83. As previously mentioned in connection with FIG. 5, a pliable sleeve 14 is used to protect the vail from unintended disengagement from the nebulizer 10.