JPH06178954A - Spray nozzle - Google Patents

Abstract

(57) [Summary] [Objective] To provide a spray nozzle design that can be used by itself to provide a nozzle that produces a spray of droplets of a size suitable for inhalation without the use of a liquefied gas propellant. A method and apparatus for atomizing a liquid is described. In this method and apparatus, liquid is forced through an annular gap formed between a spherical or conical surface and a peripheral hole in the plate. These components can be displaced with respect to each other to control the flow of liquid through the gap. The width of the gap is controlled by the stop.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to spray nozzles for use in hand held sprayers such as so-called aerosol and pump atomizers for liquid household products, cosmetics and pharmaceutical applications.

[0002]

BACKGROUND OF THE INVENTION Aerosol-type atomizers are used in a wide range of products,
It is used worldwide to apply a wide range of products such as hair sprays, furniture polishes, detergents, paints, pesticides and pharmaceuticals. To date, chlorofluorocarbons (CFC's) have been the most common propellant gases used in aerosols. This is because chlorofluorocarbons are inert, compatible with a wide range of products, can be easily liquefied at low pressure, have a nearly constant product flow rate, and have droplets with an average diameter in the range of 3 μm to 100 μm or more. This is because the spray can be created. However, CF
It was confirmed in the 1970s that C's might be the cause of the depletion of the ozone layer that protects the earth, and in 1987 many countries signed the Montreal Protocol, which would gradually eliminate the use of CFC's. Subsequently, alternative propellants were introduced, for example liquefied hydrocarbon gas such as butane, and carbon dioxide, which does not dissolve in the product. However, they were flammable, or harmful to the environment, or reacted with the product and these propellants were gradually disappearing.
Aerosols and hand-pump atomizers powered by compressed gases (eg nitrogen, air) have been extensively developed and for most applications the performance of these atomizers was adequate.

The main drawback of non-CFC's atomizers is that the smallest droplet size that can be produced is about 40 μm in diameter.
And, despite the considerable development of so-called machine-assisted nozzles, the use of high pressure (c 15 bar) pumps, and low viscous / surface tension product formulations, 40 μm is reached with prior art methods and devices. It seemed to be the lower limit. Such as ultrasonic atomizer and disc rotary generator,
There are aerosol generators used for research and in hospital applications, none of which were suitable for portable and convenient atomizers.

Further, it is possible to create a droplet having a diameter of about 5 μm by passing a high pressure liquid through a very small hole (having a diameter of 5 μm to 10 μm), but such a method is not suitable for mass production and is uneconomical. It was The main reason is that it was difficult to make very small holes in a suitable material, which requires extreme cleanliness in the manufacture of the part to prevent the holes from clogging and should be sprayed. This is because liquid ultrafiltration is required.

In veterinary therapeutic vaccination and in some human vaccination applications, a high pressure ("intra-dermal injection") is used to inject a jet of drug through the skin without the use of a needle. Spring or gas actuated pumps (125-500 bar) (so-called needleless injectors) are commonly used to turn jets into sprays to administer the drug to the nasal passages of large animals such as pigs. You can use attachments for this. However, the minimum size of the droplets obtained is of the order of 40 μm, which limits the application of these injectors.

Compressed air atomizers such as air brushes and commercial paint atomizers consume large amounts of air, for example a gas to liquid ratio of 30,000 to obtain 5 μm droplets in water.
It needs to be more than one, which is not practical for a convenient portable atomizer. Nevertheless, there are several applications that rely on smaller droplet sizes for maximum efficiency. Insecticide-like space sprays for flying insects should ideally contain droplets of 20 μm to 30 μm in diameter in order to be suspended in the air for extended periods of time, For inhalers for inhaling metered doses for use in the treatment of respiratory illness, the aerodynamic particle size is such that droplets can penetrate and adhere to the trachea, bronchi and alveoli regions of the lung. 15 μm or less, preferably 5
Must be less than μm. For an atomizer consisting of droplets with a size in a given range, 5% or more by weight of the droplets must have an aerodynamic particle size of 6.4 μm or less,
Preferably 20% or more by weight of the particles have an aerodynamic particle size of 6.4 μm or less.

In addition, the inhaler may be designed to deliver the drug to the alveoli of the lung to create a pathway for the drug, which is poorly adsorbed from the digestive tract, into the bloodstream. In order to reach the alveoli, it is important that the aerodynamic particle size of the particles is less than 10 μm, preferably 0.5 μm to 5 μm. Many drugs used in the treatment of respiratory illness are insoluble in vehicles such as water and are applied as suspensions. These agents are made into inhalable sizes of 1 μm to 5 μm. Particles of this size tend to plug the very small pores (5 μm to 10 μm) used in known devices to generate droplets about 5 μm in diameter.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to design a spray nozzle which itself can be used to provide a nozzle which produces a spray of droplets of a size suitable for inhalation without the use of a liquefied gas propellant. Is to provide. However, the present invention has an average diameter of 0.5 μm to 100 μm.
It could also be used to provide a nozzle that produces a spray of droplets in the range.

[0009]

According to the present invention, in a spray nozzle for creating a spray of droplets by passing a liquid under pressure through the nozzle, an orifice forming means for forming an orifice and a closing member for the orifice. And a first position at which the closure member cooperates with and closes the orifice and the closure member is spaced from the orifice formation means to define a gap therebetween. Is relatively movable with respect to each other with respect to the second position and further limits the relative movement between the orifice forming means and the closing member so that the width of the gap exceeds the width which produces a fine spray. A nozzle is provided that has a stop to prevent it. The present invention is mainly
It is directed to inhalers and hand-operated pumps for inhaling metered doses, but is also applicable to other applications requiring small droplets, such as certain industrial processes.

In one embodiment of the invention, the nozzle has a circular orifice which is hermetically closed by a spring-loaded ball. The action of the liquid under pressure causes the ball to displace from the orifice by an amount determined by the stop. The stop can be fixed or adjustable and the fluid exits through the gap thus formed as a thin circular sheet. As the liquid sheet expands, it thins and breaks the outer edges into droplets. The diameter of the droplet depends on the size of the gap, the pressure of the liquid, and the physical properties of the liquid. When the pressure of the liquid drops below a certain level, the ball is pressed spring tightly onto the orifice, thus
Prevents dust ingress, product evaporation, and air pollution.

In another embodiment of the invention, the liquid to be sprayed is caused to flow through the spherical surface and into the gap formed between the spherical surface and the peripheral holes of the plate. This plate is preferably made of a spring material and is arranged as a normally closed valve in sealing contact with the spherical surface. The action of the liquid under pressure pushes the plate away from the spherical surface by the amount determined by the stop. The stop can be fixed or adjustable and the fluid exits through the gap thus formed as a thin circular sheet. As the liquid sheet expands, it thins and breaks the outer edges into droplets. The diameter of the droplet depends on the size of the gap, the pressure of the liquid, and the physical properties of the liquid. When the liquid pressure drops below a predetermined level, the spring plate returns to its original position and seals against the spherical surface. Thus, dust ingress, product evaporation, and air pollution are prevented.

While in the above it has been mentioned that balls or spherical surfaces are used in cooperation with the circular orifices of the plate or nozzle, other shapes are used, for example conical surfaces cooperating with circular holes. Good. The detailed contours of the faces and holes are determined in part by the required spray pattern,
Although the present invention provides all combinations of faces and holes, it is preferred that the cross-section of at least one of the components is variable so that the gap between the components is opened and closed as a result of relative movement. . The stop ensures that the gap is of approximately constant size when the components are completely separated so that a uniform spray is obtained by passing fluid over the length of the gap. The width of the gap is preferably about 5 μm.
The ratio of the gap length L to the gap width D is preferably
It is 1 or less, and more preferably 0.5 or less. The "length" of a gap means the distance liquid has to travel in order to pass through the gap.

The surface finish of the cooperating components in the region of the interstices must be sufficiently precise so as not to adversely affect the drop size and spray pattern. For example, if there is a groove in one component, the liquid flow will exit this groove. This probably does not have the requisite properties and may reduce the pressure of the liquid enough to adversely affect the quality of the spray emerging from the rest of the gap.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a ball 1 is elastically pressed by a compression spring 6 into a predetermined position which is hermetically disposed on a circular orifice 3 of a nozzle 2. Stop means 5 are arranged on the longitudinal axis of the ball and the orifice.
This stop has a gap 8 between its face 9 and the surface of the ball 1. The nozzle 2 is in hydraulic communication with an application means (not shown) and contains the liquid 7 to be sprayed.

Referring now to FIG. 2, FIG. 2 shows the same components as in FIG. 1, in which the application means exerts pressure on the liquid 7 so that the ball 1 hits the face 9 of the stop means 5 until it stops. Is lifted from the circular orifice 3 against the force of. Thus, the ball 1 is moved by the amount controlled by the gap 8 to form the gap 10, the size of which is the amount determined by the ratio of the diameter of the ball 1 and the diameter of the circular orifice 3. Less than eight. The liquid 7 exits the gap 10 in a circular sheet having a thickness initially determined by the size of the gap 10. As the liquid sheet expands, it thins until the surface tension of the liquid fails to maintain the integrity of the sheet and breaks around the sheet into small droplets. The size of the droplet is controlled by the size of the gap 10 and the velocity of the liquid. The speed of the liquid depends on the pressure created in the application means. If the pressure in the liquid is high enough to overcome the viscous drag created by the small gap, a small gap 10 will produce small droplets that accelerate the liquid and form a thin sheet. (If the pressure is too low, the liquid will only overflow the gap.) When the pressure in the liquid 7 disappears, the ball 1 will again be in sealing engagement with the orifice 3 by the spring 6. The line of contact between the ball 1 and the orifice 3 is preferably very thin, which can easily be done by chamfering the nozzle at 4 to leave a knife edge. This has the additional effect of providing a wider spray angle Z than is possible with an orifice having a rectangular edge.

3 and 4 show a modification in which the stopping means 5 is replaced with a stopping means 5a of a modified example. The stopping means 5a has a recess 5b in which 6 is accommodated. When the nozzle is moved from the closed position shown in FIG. 3 to the open position shown in FIG. 4, the ball 1 seats itself on the open end of the recess. The guidance to do this creates a uniform tubular gap between the orifice 3 and the ball to align the ball exactly with respect to the end of the conduit 2. The spray produced is thus almost uniform both in the distribution around the gap and in the droplet size.

Modifications are shown in FIGS. 5 and 6. In this case, FIG. 5 shows the spherical surface 20 located at the outer edge of the discharge conduit 21 containing the liquid 22 to be sprayed. The spring plate 24 with the circular orifice 25 has a spherical surface 20 such that the circular orifice 25 makes sealing contact with the spherical surface 20.
The outer edge of the spring plate 24 is held against the conduit 2
Is in sealing contact with the abutment surface 26 of No. 1, thus
The liquid 22 is prevented from passing through. A plate 27 having a circular hole 29 is incorporated on the outer surface of the spring plate 24 so that the hole 29 is coaxial with the orifice 25. The stop or recess 30 in the plate 27 defines a gap 28 between the spring plate 24 and the plate 27, and the two plate assembly is held in sealing contact with the abutment 26 by a retaining member 33. The holding member 33 may be crimped as shown.

Referring to FIG. 6, the liquid 22 is pressurized by the application means (not shown) to move the plate 24 from the spherical surface 20 against the inherent pressing force given by the plate 24 being a spring plate. Push away, circular orifice 25
A gap 32 is formed between the spherical surface 20 and the spherical surface 20. The size of the gap 32 is determined by the size of the gap 28 and the diameter of the hole 29 of the plate 27. Of these, the diameter of the hole 29 in the plate 27 determines how much the spring plate 24 can flex. The liquid exits the gap 32 as a thin circular sheet, the periphery of which breaks into droplets as described above. The edge of the circular orifice of the spring plate 24 is shown in FIG.
It may be chamfered, as shown in Figure 3, which allows for a wider spray than is possible with a rectangular edged orifice. The spring plate 24 is
As shown in FIG. 8, it may have a fold that is coaxial with the orifice 25, which facilitates flexing of the spring plate. When the pressure is removed from the liquid 22, the spring plate 24 returns to sealing contact with the spherical surface 20.

In FIGS. 5 and 6, the spherical surface 20 is shown schematically as it is provided at the end of the rod and means (not shown) are needed to support this rod with respect to the liquid discharge conduit 21. To be done. 9 and 10 show a disk 50 fixed to or integral with the inner wall of the conduit 21.
A modification in which the spherical surface 20a is formed is shown. The disk 50 is provided with at least one port 51, through which liquid can flow from the interior of the conduit 21 to the plate 2
You can pass up to the area just below 4. 11 to 13 show
1 shows a spraying device incorporating a spraying nozzle according to the invention.
It is intended to be used as an inhaler. The device has a reservoir 60 of liquid 61. Liquid 61
May consist, for example, of an aqueous suspension of a medicament suitable for treating conditions such as asthma. . The lower end of the reservoir is constituted by a piston 62 which is slidable in the reservoir in the longitudinal direction. Below the piston is provided a stopper 63 having at least one orifice 64 which allows air to enter the space below the piston.

The upper end of the reservoir has a neck portion 65 to which a closure member 66 is fixed. A portion 67 of the closure member extends into the neck and an O-ring seal 68 is included in the neck portion 65.
Forming a seal between the and the portion 67. The closure member 66 has a through passage 69 with a tube 70 secured to the upper portion of this passage. The lower part of the passage constitutes the orifice 71,
The top of this orifice is a tapered portion that forms a seat for seating the ball 72 of the check valve. The ball is pressed against the seat by a compression spring 73. Outlet member 7
Closure member 6 such that 4 is movable relative to closure member 66.
It is attached to 6. The outlet member 74 has a generally cylindrical component 75, the lower end of which engages on the closure member 66. The component 75 is designed so as not to separate from the closure member 66 by the mutual engagement of the flanges 76 and 77. The outlet member 74 further has a spout 78 through which a user can inhale through the spout. In the case of a nasal aspirator, spout 78 may be replaced by a suitable nasal outlet.

In the area of the connection between the cylindrical part 75 and the outlet 78, the outlet member 74 has an inwardly extending wall 79 which serves to hold the spray mechanism 80. This spray mechanism has a block 81 with a hollow lower part 82,
Surrounds the upper end of tube 70 and is free to enter cavity 83 at the upper end of closure member 66. The hollow portion 82 has an outwardly extending flange 84 at its upper end, and a compression spring 85 is mounted between this flange and the closure member 66. The interior of the hollow portion 82 communicates with the spray nozzle 90 according to the invention via a passage 86. This is enlarged and shown in FIG. As can be seen in FIG. 13, this corresponds substantially to that shown in FIGS. 9 and 10 and has a spring plate 91 cooperating with a spherical surface 92 formed on the disc 93.
The disk 93 is provided with at least one through port 94.

In operation, the user places the spout over the spout 78 and causes the reservoir 60 and the outlet member 74 together to compress the spring 8.
Squeeze against the force of 5 to bring the device into the state shown in FIG. During this operation, the liquid in the ball 72 is the orifice 71.
Keeping the reservoir 60 undisturbed therethrough, the tube 70 acts as a piston to expel the portion of the liquid above the ball through the nozzle 90. The liquid is sprayed at the nozzle 90. The amount of liquid expelled in this way constitutes a metered dose, the metering being effected by the stroke of the piston. The user aspirates this spray. When the user stops holding the reservoir 60 and outlet member 74 together, spring 85 pushes them apart. This creates a suction effect in the tube 70, which moves the ball away from its seat and allows the liquid to be replenished from the reservoir through the orifice 71 and through the nozzle 90. When the volume of liquid in the reservoir becomes small, the piston 62 slides upward due to the force of atmospheric pressure acting below it.
Air reaches the underside of the piston through port 64.

FIG. 14 shows another modification of the spraying device.
This figure shows the device in the eject position. In this embodiment, a valve of similar design to the valve used as the spray nozzle is also used as the check inlet valve. FIG. 14 shows the actuator 101 hermetically arranged on a hollow stem 104 integral with a hollow piston 107. The piston 107 is hermetically arranged in a cylinder 115, which is formed as an internal part of the pump body 108. This body is a snap-fit or other convenient retention method for the closure 1.
Retained within 05, a gasket 106 forms a seal between the stem 104 and the closure 105. Gasket 1
06 flexes freely with axial displacement of the piston and stem while maintaining a seal. Piston 107
A plurality of cantilever springs 109 integrally formed with the piston act on a conical surface 110 formed on the lower portion of the pump body 108 to push the piston outward. The piston is the closing body 105
An abutment 116 closed on a gasket 106 supported by the inside of the ball prevents the ball body 108 from slipping out.

The lower end of the pump body 108 includes a spherical surface 111. The flexible diaphragm 112 and its circular hole are hermetically disposed within the pump body 108 such that the edge of the diaphragm hole sealingly engages the spherical surface 111. The combination of diaphragm 112 and surface 111 acts as a normally closed check valve 120. The bottom portion of the pump body 108 terminates in a diameter adapted to hermetically retain the dip tube 113. The conduit formed by the dip tube 113 and the lowermost portion of the pump body 108 are in communication with a ring 119 formed between the spherical surface 111 and the diaphragm 112 via one or more ports 117. The actuator 101 has a spherical surface 103 and a flexible diaphragm 102 with a circular hole, the edge of which is spherical surface 103.
Is in sealing engagement with. The diaphragm 102 is hermetically disposed within the actuator 101 with a snap fit or other convenient method, and the combination of diaphragm 102 and face 103 acts as a check valve and spray nozzle 121.
Hollow stem 104 communicates with annulus 114 via port 108. In operation, the actuator is pushed back several times to prime the pump and valves 120 and 121 cooperate to withdraw liquid from a reservoir (not shown) and expel liquid from the spray nozzle.

FIG. 15 shows a spray nozzle provided with means for adjusting the clearance through which the liquid passes, unlike the above-mentioned embodiment. The nozzle has an externally threaded body 201 for receiving a threaded cap 202. The cap can be adjusted to change the gap 203 formed between the face 204 of the cap and the flexible diaphragm 205. In this way, the emission characteristics can be easily changed. For example, the atomization can be adjusted from fine droplets to coarse droplets. The term "liquid" as used herein includes solutions, suspensions and emulsions.

[Brief description of drawings]

1 is a cross-sectional view of the basic components in a normal, non-pressurized relationship, which illustrates the principles of the present invention.

FIG. 2 is a view similar to FIG. 1, showing the components in the operative position.

FIG. 3 is a diagram showing a modification of the embodiment of FIG.

FIG. 4 is a diagram showing a modification of the embodiment of FIG.

FIG. 5 is a diagram showing a modified example of the principle of the present invention in the closed position.

FIG. 6 is a diagram showing a modified example of the principle of the present invention in the open position.

FIG. 7 is an enlarged partial cross-sectional view showing a meeting portion of main components shown in FIGS. 5 and 6;

FIG. 8 is a cross-sectional view of a modification of the spring plate used in the embodiment of FIGS. 5 and 6.

FIG. 9 is a diagram showing a modification of the embodiment of FIG.

FIG. 10 is a diagram showing a modification of the embodiment of FIG.

FIG. 11 is a diagram of a nebulizing device for use as an inhaler, incorporating a nozzle according to the invention.

FIG. 12 is a diagram of a nebulizer device for use as an inhaler, incorporating a nozzle according to the present invention.

FIG. 13 is an enlarged view showing the nozzle used in FIGS. 11 and 12.

FIG. 14 shows another form of atomizer incorporating a nozzle according to the invention.

FIG. 15 is a diagram of an embodiment of a nozzle in which the size of the gap is adjustable.

[Explanation of symbols]

 1 Ball 2 Nozzle 3 Orifice 4 Waste Collection Container 5 Stopping Means 6 Spring 7 Liquid 8 Gap 9 Surface 10 Gap

Claims (22)

[Claims] 1. A spray nozzle for producing a spray of droplets by passing a liquid under pressure through the nozzle, comprising an orifice forming means forming an orifice and an orifice closing member, the orifice forming means and closing. The member is relative with respect to each other between a first position in which the closure member cooperates with the orifice to close it and a second position in which the closure member is spaced from the orifice defining means to define a gap therebetween. And a stop for limiting the relative movement between the orifice forming means and the closing member so that the width of the gap does not exceed the width for producing a fine spray, nozzle. 2. The nozzle according to claim 1, wherein the orifice has a circular shape. 3. The nozzle according to claim 2, wherein the closure member has an at least partially spherical surface arranged to cooperate with the orifice. 4. The nozzle according to claim 1, 2 or 3, wherein the orifice forming means is a flexible diaphragm. 5. The nozzle of claim 4, wherein the diaphragm is provided with at least one fold surrounding the orifice, thereby increasing the flexibility of the diaphragm. 6. A nozzle according to claim 4 or 5, wherein the stop comprises an annular ring having a stop surface adjacent the diaphragm but spaced from the diaphragm. 7. The closure member is a spherical ball.
7. The nozzle according to any one of items 1 to 6. 8. A nozzle according to any one of the preceding claims, wherein the orifice forming means and the closing member are movable relative to each other by the action of the force exerted by the pressure of the liquid. 9. The orifice has a chamfered peripheral surface,
The nozzle according to any one of claims 1 to 8, wherein the chamfering direction is a direction that reduces the length of the gap. 10. The nozzle according to claim 1, wherein the width of the gap is on the order of 5 μm. 11. The nozzle according to claim 1, wherein a value L / D of a ratio of a width D of the gap to a length L of the gap is 1 or less. 12. The nozzle according to claim 11, wherein the L / D value is 0.5 or less. 13. The nozzle according to claim 1, wherein the orifice forming means and the closing member are pressed to the first position. 14. The nozzle according to claim 13, wherein the pressing force is an elastic pressing force. 15. The nozzle according to claim 14, wherein the elastic pressing force is provided by an elastically movable orifice component. 16. A spray nozzle according to any one of claims 1 to 15, a supply source of the liquid, and means for supplying a pressurized liquid from the supply source to the nozzle. And a spraying device having. 17. A device according to claim 16, comprising metering means for ensuring that the liquid passing through the nozzle is a metered amount. 18. A device according to claim 16 or 17, wherein the liquid comprises a medicament suitable for inhalation. 19. The device of claim 18, wherein the liquid contains the drug in suspension. 20. The device of claim 18, wherein the liquid contains the drug in solution. 21. A device according to any one of claims 18, 19 or 20, wherein the liquid is a physiologically acceptable aqueous liquid. 22. A device according to any one of claims 18, 19 or 20, wherein the liquid is a physiologically acceptable non-aqueous liquid.