JP2006075385A - Aerosol generating device and method of generating aerosol using the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a large quantity of fine mist in an aerosol generating device used in a jet type nebulizer. <P>SOLUTION: A gas lead-in tube 6 is disposed for leading in a gas upward from the center on the bottom of a container 1 of the aerosol generating device, and a cylindrical body 9 with a narrow aperture 8 at the center on the upper face covers the outside of the gas lead-in tube 6. A cylindrical slit whose width is in the range from 2.0 to 0.3 mm is formed between the outer wall 10 of the gas lead-in tube 6 and the inner wall 12 of the cylindrical body 9 almost over the whole height of the outer wall 10 of the gas lead-in tube 6. A baffle 11 is disposed with a distance from the aperture 8 on the upper face of the cylindrical body 9, and a convex face R is formed on the baffle and a concave face 14 is formed on the upper surface of the cylindrical body 9. The concave face 14 passes the aperture 8 and is concentric with the convex face R, with a larger curvature than that of the convex face R. A curved-face slit is formed between the convex face R and the concave face 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for generating an aerosol mainly used for medical treatment and is used for respiratory therapy.

  An aerosol generator used for medical treatment is called a nebulizer and has a long history. Inhaled gas introduced into the respiratory tract with a ventilator is oxygen or an air / oxygen mixed gas with an increased amount of oxygen, which is introduced into the respiratory tract when treating a patient, but the inspired gas contains moisture. Therefore, humidification with a nebulizer is necessary.

  Aerosols produced from sterilized purified water or physiological saline are exclusively used as aerosols for the treatment of breathing, and the generation principle of aerosols is found in the market such as jet type, ultrasonic type, quantitative spray type, and mesh type. There are also significant advances in ventilators used to treat patients with respiratory failure, and many ventilators are on the market, but there are a wide variety of nebulizers used in combination with these ventilators, Each has advantages and disadvantages. It has recently become known that the size of the mist must be around 2 μm in order for the mist dispersed in the aerosol supplied by these nebulizers to reach the alveoli of the patient. For this reason, there is a strong demand for the emergence of aerosol generators that generate aerosols having an average particle size of around 2 μm at a high concentration.

  The aerosol mist from the nebulizer varies in size and distribution depending on the mist generation method, and there is still no nebulizer having the most desirable mist size and distribution and producing a high concentration aerosol. In order for the mist to reach the alveoli, which is the distal tip of the airway, its size must be 2 μm or less. Jet type nebulizers produce very good mist, but the particle size is 5-15 microns larger than other nebulizers, and the uniformity is greatly inferior. In the jet type nebulizer, the characteristics of the liquid (concentration, adhesiveness, surface tension), the flow rate of the injected gas, and the like greatly affect the particle size. Among them, the influence of the gas flow rate is great, and it is difficult to always keep the particle size within a certain range.

  In particular, since the mist particles are relatively large, the possibility that the mist reaches the airway periphery and alveoli is extremely low, and most of them are deposited in the nasal cavity or upper airway. In the ultrasonic nebulizer, the size of the mist particles is relatively preferable as 1 to 5 μm, but a large amount of mist cannot be generated, and in order to generate a large amount of mist, the apparatus itself is large and heavy. . In addition, there is an essential drawback that the chemical components change with time.

  The metered spray nebulizer has a mist size of 2.4 to 5.5 μm and is light and inexpensive, but has a low mist generation capability and an extremely low humidification effect. The mesh type nebulizer has a mist size of about 2.0 μm, and the mist reaches the peripheral airway. However, it is expensive and the amount of mist generated cannot be increased, and its use is limited. Currently, nebulizers that have a narrow distribution of mist generated around 2 μm and are capable of generating aerosols at high concentrations are drooling from the standpoint of respiratory therapy, but they are not yet present. is there.

  The aerosol generator according to the present invention includes a container for storing a liquid, a gas introduction pipe standing on the bottom surface of the container, and first pores formed on the top surface of the gas introduction pipe for ejecting the introduction gas upward. A cylindrical body disposed so as to cover the outer periphery and the upper surface of the gas introduction pipe, and an upper surface of the cylindrical body so as to be spaced above the first pore. A second baffle disposed at a distance above the second pore, and between the lower portion of the cylindrical body and the bottom surface of the container, Is formed in a gap formed between the outer periphery of the gas introduction tube and the inner periphery of the cylindrical body, and the outer periphery of the gas introduction tube and the inner periphery of the cylindrical body are The width of the gap formed between is 2.0 to 0.3 mm. The baffle includes a convex curved surface formed so as to protrude toward the second pore, and the upper surface of the cylindrical body has the convex curved surface around the second pore. A concave curved surface having the same center of curvature and a curvature larger than that of the convex curved surface, and a curved slit formed between the convex curved surface of the baffle and the concave curved surface of the cylindrical body. It may be.

Further, aerosol generating method according to the invention, the aerosol generator described above, wherein the gas pressure to actuate the aerosol generator is in the range of ^{1.0kg / cm 2 ~4.0kg / cm 2} .

  The present invention provides a small and inexpensive aerosol generator that generates high-concentration aerosol of mist with a particle size of 2 μm, which is drooping in respiratory medicine, to the peripheral airway, which has been impossible in the past, and even to the alveoli. It provides the means to reach the aerosol mist and brings about the effect of opening a new era in respiratory therapy.

  Since the present invention has been completed by introducing a completely new idea into a jet nebulizer, the principle and drawbacks of the current jet nebulizer will be described with reference to FIG. 1 before describing the present invention.

  1A, 1B and 1C illustrate the principle. In either case, a thin T-shaped tube 2 is vertically set up in a container 1 containing a liquid, and a jet flow strikes the tip of the vertical tube 3 from the side. FIG. 1D shows a typical variation thereof. FIG. 1C and FIG. 1D show a venturi tube principle that sucks air from an external atmosphere and blows out an increased amount of gas. In the case of FIG. 1C, an air suction port 4 is provided on the downstream side of the vertical pipe 3. Further, in the case of FIG. 1D, the blowout port 7 of the gas introduction pipe 6 is arranged on the upstream side of the tip of the vertical pipe 3 located in the air passage 5.

  The reason why the liquid rises in the vertical pipe 3 is that the tip of the vertical pipe 3 (part where the horizontal pipe through which the drive gas flows is partially thinned) is decompressed by Bernoulli's law. Then, the jet flow hits the sucked liquid, and the sucked liquid is dispersed into fine particles. Here, the shortcomings can be summarized as follows: (1) The sucked liquid becomes a mist only a part, and most of the liquid is dispersed around and returns to the container. That is, the utilization efficiency of the liquid is extremely poor. (2) A large amount of liquid cannot be sucked up because the liquid is sucked up by a thin tube (vertical tube 3).

  The inventor fundamentally changed the idea, studied the method of making the most of the effect while fully utilizing the features of the jet nebulizer, realized various ideas, accumulated ideas, and reached the present invention did.

  The inventor has earnestly thought that a nebulizer that can meet the demands of the market can be made by drastically improving the shortcomings of the oldest and widely used jet type nebulizer in history. As a result of research, the present invention has been achieved. Hereinafter, the present invention will be specifically described with reference to FIG.

  A feature of the present invention is an apparatus for generating aerosol, in which a gas introduction pipe 6 that introduces gas upward from the center of the bottom surface of the container 1 is provided and covered with the gas introduction pipe 6. A cylindrical body 9 having a pore 8 at the center of the upper surface is disposed so as to surround the gas introduction pipe 6, and an outer wall of the gas introduction pipe 6 is interposed between the cylindrical body 9 and the gas introduction pipe 6. A cylindrical slit is formed over almost the entire height of 10, a gap is formed between the cylindrical body 9 and the bottom surface of the container 1, and a gap is placed from the pore 8 on the upper surface of the cylindrical body 9. The present invention relates to an improvement of an aerosol generator characterized in that a baffle 11 is provided.

  The first feature of the present invention is that the gas inlet pipe 6 and the cylindrical body 9 covering the gas inlet pipe 6 form a venturi pipe. Therefore, when a high-speed gas flow flows into the gas inlet pipe 6, the nebulizer container 1 According to the Venturi's law, the liquid is sucked up by utilizing the entire volume of the slit between the gas introduction pipe 6 and the cylindrical body 9 covering the gas inlet pipe 6, so that a large amount of liquid is sucked up. Compared with the amount of liquid sucked up through a thin tube, there is a big difference. That is, by using the slits to suck up a large volume of liquid, it should be possible to produce a high-concentration aerosol that has been dripping up to now but could not be realized.

Recently, Mr. Okada has proposed the same nebulizer proposed by Dr. Bird (Japanese Patent Laid-Open No. 11-128348), but its contents are all known from Dr. Bird's paper.
JP-A-11-128348 The FLYING PHYSICIAN (VOLUME 30, NO.2, JUNE 1987 the Flying Physicians Association)

  The basic concept of this type of nebulizer was proposed by Dr. Bird, but there were many problems that had to be solved before it could be put into practical use. The present inventor has solved the problem and arrived at the present invention.

  In other words, in order to realize the effects of the present invention, it was found that specific conditions were indispensable, and various improvements were attempted with the advice of Dr. Forest Bird, the inventor of the basic concept. It is a thing. The present inventor has found that the width of the slit is extremely important for sucking up a large amount of liquid, and that the effect of the present invention is not seen at all unless a specific condition is satisfied. Hereinafter, the features of the aerosol generator of the present invention will be described with reference to FIG. In FIG. 3, only the container portion is shown, and the upper side of the container portion is connected to a member having the air passage 5 similar to FIG.

  It is essential that the width W1 of the slit between the gas introduction pipe 6 and the cylindrical body 9 covering it is 2 mm to 0.3 mm. When the width W1 is 2 mm or more, the liquid cannot be sufficiently sucked due to the weight of the liquid, and the amount of aerosolized liquid is reduced. When the width is smaller than 0.3 mm, the liquid sucking amount is reduced and the effect of the present invention is reduced. Cannot be pulled out to the maximum. The most desirable slit width W1 is 1.5 mm to 0.7 mm.

  The second feature of the present invention is the misting efficiency of the sucked liquid. As described in the section of the prior art, in the conventional method, the sucked liquid is jetted from a direction perpendicular to the liquid flow, so that the portion to be mist is limited and the equivalent of the sucked liquid. The amount falls without being mist, so it cannot be said that efficiency is good.

  In the present invention, the liquid rising through the cylindrical slit formed between the outer wall 10 of the gas introduction pipe 6 and the inner wall 12 of the cylindrical body 9 covering the gas flows toward the pores 8 at the upper part of the cylindrical body 9. To gather naturally. And since the high-speed gas is sprayed there, the liquid is completely misted with almost no loss. Since the large amount of liquid is efficiently misted in combination with the first feature described above, the device of the present invention that generates a high concentration aerosol can be realized.

  A third feature of the present invention is the convergence of the generated aerosol stream. As already described, the liquid rising through the slit in the length (height) direction of the gas introduction pipe 6 gathers toward the space below the pores 8 in the center of the upper surface of the cylindrical body 9, and there It collides violently with the high-speed jet gas from the gas introduction pipe 6 and becomes mist. At that time, the generated aerosol mist consists of two pores, that is, two pores 13 arranged in a straight line, ie, the pore 13 at the tip of the gas introduction tube 6 and the pore 8 of the cylindrical body 9 disposed so as to cover it. It is created by a high velocity jet gas flow through the pores 13,8. The pores 8 and 13 need to be larger in size than the pores 13. Otherwise, the gas flow released from the pores 13 is restricted at the pores 8 and the amount of mist is reduced, which is not preferable.

  The fourth feature of the present invention is that the aerosol flow ejected from the pores 8 on the upper surface of the cylindrical body 9 immediately collides with the baffle 11 forming the curved surface R, so that the mist particles are redivided into finer ultrafine particles. It is in. According to the fourth feature of the present invention, the aerosol mist that collides with the baffle 11 is always restricted to the central portion of the curved surface R of the baffle 11 and can collide with the same place. It was realized that the size of the mist particles was narrowly distributed around 2 μm. With this technique of the present invention, the generated aerosol can be applied to the lung airway for medical use, and a large amount of aerosol mist can be introduced to the peripheral part of the airway and the alveoli. This is not possible with a conventional nebulizer.

  The curved surface R of the baffle 11 has a convex curved surface, and the radius of curvature is preferably 10 mm to 3 mm, more preferably 9 mm to 5 mm, and still more preferably 8 mm to 6 mm. If the radius of curvature is smaller than 3 mm, a part where the aerosol flow obliquely collides with the curved surface R of the baffle 11 is generated, and a part that slips along the curved surface of the baffle with insufficient repulverization and ultrafine particle generation occurs. , The mist particles become irregularly large and the distribution becomes wide. If the radius of curvature is larger than 10 mm, the mist is efficiently pulverized, but the problem is that the aerosol does not flow smoothly.

  The fifth feature of the present invention is the shape around the pores 8 on the upper surface of the cylindrical body 9 arranged so as to cover the gas introduction pipe 6. The peripheral portion with the pore 8 forms a concave curved surface 14 corresponding to the convex curved surface R of the baffle 11 corresponding thereto, and a slit forming a curved surface between the concave curved surface 14 and the convex curved surface of the baffle 11. Is formed, and the width W2 of the slit is set to be constant.

  More specifically, for example, the curvature radius of the convex curved surface of the baffle 11 is 8 mm, and the pore portion on the upper surface of the cylindrical body 9 passes through the pore 8 and is concentric with the convex curved surface of the baffle 11. The curvature radius is 9 mm, and in that case, the slit width W2 between both curved surfaces is 1 mm. The feature of the present invention is that the convex curved surface of the baffle 11 and the concave curved surface 14 of the pore portion are opposed to each other to form a curved slit, the details of which are shown in FIG. Street.

  A sixth feature of the present invention is that a concave curved surface 14 having a large curvature and concentric with the convex curved surface of the baffle 11 passing through the pores 8 on the upper surface of the cylindrical body 9 and a slit width W2 to the convex curved surface of the baffle 11 are provided. It is very narrow, and the distance is within 3 mm, and needs to be 3 mm to 0.5 mm. More preferably, it is 2 mm-0.5 mm, More preferably, it is 1.5 mm-0.7 mm.

  If this distance is larger than 3 mm, the center of the distribution of the size of the generated mist becomes larger than 2 μm, and the width of the distribution becomes large, which is not preferable. On the other hand, if this distance is smaller than 0.5 mm, the path of the generated aerosol becomes too narrow, which may cause trouble. In this case, the flow of the generated aerosol is undesirably disturbed.

  The seventh feature of the present invention is that it is extremely small and lightweight while having many features already described. In short, the aerosol generator according to the present invention is a size that can be easily held with one hand, which is extremely important in practical use. In fact, the nebulizer according to the present invention can have an outer diameter of 5 cm or less, and the container height can be reduced to 5 to 6 cm. In conventional products, if 2 μm mist particles are to be made, they become extremely large and heavy like an ultrasonic device, and the amount of aerosol generated is small. In addition, in conventional jet-type devices that generate high-concentration aerosols, the size of mist particles is usually large, and even when applied to medical applications, most of them are deposited in the upper respiratory tract, resulting in fine particles. It does not reach the bronchi, peripheral bronchi and alveoli, and is not sufficient for therapeutic purposes.

  The present invention has successfully solved many problems that have not been solved so far, and has completed a drooling aerosol generator on the market.

In practicing the present invention, a positive pressure gas is introduced from a gas introduction pipe. In order to obtain a desired size of mist particles and a desired mist distribution, the pressure of the introduced gas is important. Pressure of the introduced gas is preferably 1.0 kg / cm ² or more 4.0 kg / cm ² or less, more preferably, 1.4 kg / cm ² or more 3.5 kg / cm ² or less, more preferably, 2.0 kg / cm ² or more and 3.0 kg / cm ² or less. The pressure of the introduced gas is 1.0 kg / cm ² or less Then, the flow velocity of the aerosol flow is too low to disperse in the desired particle shape, and if it is 4.0 kg / cm ² or more, the dispersion is too effective and the mist particle shape is too fine to be called without being deposited in the airway. On the contrary, it is not preferable because mist increases. As long as the gas pressure is regulated within the above range, the mist size is hardly affected. This can be said to be the eighth feature of the present invention.

  As described above, the present inventor paid attention to the dynamic behavior of the fluid, introduced a new idea, proceeded with intensive studies, finally solved the current problems, made it cheap, lightweight and preferred mist particles Has led to the invention of an aerosol generating device containing a high concentration of.

  The present invention replaces the venturi tube with a method of sucking a large amount of liquid through the slit and sucking it with a conventional thin tube, further condensing the sucked liquid at one point, causing jet gas to act on it, and generating aerosol in the baffle immediately after that It was made to collide and re-grind the mist, and succeeded in obtaining a high concentration ultra fine mist.

  The following reference examples and examples further illustrate the present invention in more detail, but in no way limit the scope of the claims of the present invention.

The aerosol generator according to the present invention shown in FIG. 3 was used. The outer diameter of the container 1 portion is 46 mm, and the height is 55 mm. The height of the portion of the gas introduction pipe 6 protruding into the container 1 is 20 mm, and the outer diameter is 5 mm. The inner diameter of the cylindrical body 9 covering the gas introduction pipe 6 was 7 mm. Therefore, the width W1 of the slit between the gas introduction pipe 6 and the cylindrical body 9 covering the gas introduction pipe 6 was 1 mm. In this example, the curved surface R of the baffle 11 is a convex spherical surface and its radius of curvature is 8 mm. Correspondingly, the concave curved surface 14 on the upper surface of the cylindrical body 9 passes through the pore 8 and the convex curved surface of the baffle 11. Concentric concave spherical surface is formed, and the radius of curvature thereof is 9 mm. Therefore, the distance between the pore 8 and the curved surface R of the baffle 11 is 1 mm. Aerosol was generated using this device. In this example, the gas introduction pressure was 2.8 kg / cm ² . In this case, the gas flow rate was 8 liters per minute. The distribution of aerosol particles is shown in FIG. It can be seen that most of the particles have a sharp distribution centered on 2 μm and below 5 μm. The amount of aerosol generated was 2.8 ml per minute.

Using the same apparatus as in Example 1, the same experiment was performed by changing the gas flow rate. The relationship between the average particle size obtained and the gas flow rate is shown in FIG. It can be seen that the apparatus of the present invention can stably obtain mist particles centered at 2 μm even if the flow rate is changed within the range of this experiment. In this example, the gas flow rate per minute 11-6 l is equivalent to the pressure of 4.0kg ^/ cm ² ~1.0kg ^/ cm 2 of the introduced gas.

[Reference Example 1]
Example 1 except that the radius of curvature of the convex curved surface R of the baffle 11 is 2.3 mm and the concave curved surface 14 having the pores 8 on the upper surface of the cylindrical body 9 corresponding thereto has a curvature of 3.3 mm. Is the same. When this example was carried out under the same conditions as in Example 1 and the particle distribution of the produced aerosol was measured, it was as shown by the solid line in FIG. 6 (X display). Compared with the data of Example 1 shown by the bar graph, it can be seen that the peak position moves to around 3 μm and the particle size is larger.

[Reference Example 2]
Example 1 is the same as Example 1 except that the distance from the curved surface R of the baffle 11 to the pores 8 on the upper surface of the cylindrical body 9 is 5 mm. The size distribution state of the aerosol particles obtained under these conditions is indicated by a dotted line in FIG. 6 (Y display). In this case, since the distance from the pore 8 on the upper surface of the cylindrical body 9 to the curved surface R of the baffle 11 is increased, the effect of re-pulverizing mist particles is drastically reduced, and it can be seen that the particle distribution moves to the larger one.

[Reference Example 3]
FIG. 6 shows the distribution state of aerosol mist when no baffle is used (Z display). The particle size is large and broad.

[Reference Example 4]
The apparatus of the first embodiment is exactly the same as the first embodiment except that the distance between the outer wall of the gas introduction pipe and the inner wall of the cylindrical body covering it, in other words, the slit width is 2.2 mm. In this example, aerosolization of the liquid was inferior, and the amount of aerosol generated was 1.8 ml / min.

It is a figure which shows schematically the principle and fault of the present jet nebulizer. 1 is a schematic cross-sectional view of an aerosol generator according to the present invention. It is sectional drawing which shows the feature point of the aerosol generator by this invention. It is a figure which shows distribution of the aerosol particle | grains when the flow rate of gas is 8 liters per minute. It is a figure which shows the relationship between the average magnitude | size of the aerosol particle obtained in the aerosol generator by this invention, and a gas flow rate. It is a distribution map of the size of aerosol particles generated under the conditions of Reference Examples 1 to 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 6 Gas introduction pipe 8 Fine pore 9 Cylindrical body 10 Outer wall 11 Baffle 12 Inner wall 13 Fine pore R Curved surface W1 Slit width W2 Slit width

Claims (3)

A container for liquid,
A gas introduction pipe standing on the bottom of the container;
A first fine hole formed on the upper surface of the gas introduction pipe and ejecting the introduction gas upward;
A cylindrical body arranged to cover the outer periphery and the upper surface of the gas introduction pipe;
Second pores formed on the upper surface of the cylindrical body so as to be spaced above the first pores;
A baffle disposed at an interval above the second pore,
Between the lower part of the cylindrical body and the bottom surface of the container, the liquid in the container is introduced into a gap formed between the outer periphery of the gas introduction pipe and the inner periphery of the cylindrical body. Gap is formed,
An aerosol generator, wherein a width of a gap formed between an outer periphery of the gas introduction pipe and an inner periphery of the cylindrical body is 2.0 to 0.3 mm. A container for liquid,
A gas introduction pipe standing on the bottom of the container;
A first fine hole formed on the upper surface of the gas introduction pipe and ejecting the introduction gas upward;
A cylindrical body arranged to cover the outer periphery and the upper surface of the gas introduction pipe;
Second pores formed on the upper surface of the cylindrical body so as to be spaced above the first pores;
A baffle disposed at an interval above the second pore,
Between the lower part of the cylindrical body and the bottom surface of the container, the liquid in the container is introduced into a gap formed between the outer periphery of the gas introduction pipe and the inner periphery of the cylindrical body. Gap is formed,
The baffle includes a convex curved surface formed to protrude toward the second pore,
On the upper surface of the cylindrical body, a concave curved surface having the same curvature center as that of the convex curved surface and a curvature larger than the curvature of the convex curved surface is provided around the second pore.
An aerosol generator, wherein a curved slit is formed between the convex curved surface of the baffle and the concave curved surface of the cylindrical body. In aerosol generator according to claim 1 or claim 2, aerosol method occurs, wherein the gas pressure to actuate the aerosol generator is in the range of 1.0kg / cm ² ~4.0kg / cm ² .

Images