High frequency droplet delivery system and method

Abstract

An aerosol-generating method includes: operating an electronic transducer to vibrate at a first frequency; coupling the grid having a predetermined aperture size to an electronic transducer; providing a fluid composition to the grid when the transducer vibrates at a first frequency; operating the electronic transducer at a second frequency higher than the first frequency; providing the same fluid composition to the mesh when the transducer vibrates at the second frequency; and generating droplets smaller than the first frequency through the mesh at a second frequency while maintaining the predetermined hole size.

Description

Technical Field

[0001] The present disclosure relates generally to aerosol generating devices including a vibrating transducer such as a piezoelectric transducer. Examples include droplet delivery devices that deliver fluids inhaled into the mouth, throat, nose, and / or lungs. Background Art

[0002] Aerosol generating devices can include vibrating transducers, such as piezoelectric transducers, to produce aerosolized droplets for various applications. Some aerosol generating devices include droplet delivery systems intended for treatment and non-therapeutic purposes. Current droplet delivery systems include systems of various inhaler types. Some examples are metered dose inhalers (MDIs), pressurized metered dose inhalers (p-MDIs), pneumatic devices, and ultrasonically driven devices. Such droplet delivery systems are intended for treatment and non-therapeutic purposes, and can include mouthpieces and nosepieces provided for inhaling fluid droplets. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The novel features of the present disclosure are set forth in detail in the appended claims. The features and advantages of the inventive concept will be better understood by reference to the following detailed description of illustrative examples of utilizing the principles of the present disclosure and the accompanying drawings, in which:

[0004] Figure 1 The generation of droplets using lower and higher frequencies for a given mesh size is illustrated in accordance with an embodiment of the present disclosure.

[0005] Figure 2 is a cross-sectional view of the main components of a droplet delivery device according to an embodiment of the present disclosure.

[0006] Figure 3 Illustrated is a cross-sectional view of a vibrating member housing of a droplet delivery device utilizing membrane driven aerosolization according to one embodiment of the present disclosure.

[0007] Figure 4A Illustrated is a side view of an exemplary orifice plate and annular ring according to an embodiment of the present disclosure.

[0008] Figure 4B Illustrated is a top view of an exemplary orifice plate and annular ring according to an embodiment of the present disclosure.

[0009] Figure 4C Illustrated are cross-sections of exemplary orifice plates and annular ring structures according to embodiments of the present disclosure. DETAILED DESCRIPTION

[0010] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, process, article, or apparatus. In addition, unless expressly stated otherwise, "or" refers to an inclusive or and not an exclusive or. For example, a condition A or B is satisfied by any of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0011] As used herein, the term "substantially" is defined as conforming substantially to a particular dimension, shape, or substantially modified such that the part does not require precision other words. For example, substantially cylindrical means that the object resembles a cylinder, but may have one or more deviations from a true cylinder.

[0012] The term "coupled" is defined as connected, whether directly or indirectly through intermediate components, and is not necessarily limited to physical connections. The connection may be such that the objects are permanently connected or releasably connected. The term "comprising" means "including but not necessarily limited to"; it specifically indicates open inclusion or membership in a stated combination, group, series, etc.

[0013] The droplet delivery device includes an ejector mechanism having a mesh, orifice plate, or similar substrate having holes of a desired size and producing a desired surface contact angle, and generating droplets from liquid passing through the mesh when a kinetic transducer acts on the liquid and the ejector mechanism. In some devices, the membrane can be oscillated by the kinetic transducer to push the liquid through the mesh and generate droplets ("push mode"), while in other devices, the transducer can be directly coupled to oscillate the mesh to generate droplets. Examples of devices including such an ejector mechanism with a substrate having holes are disclosed in U.S. Patent Application Publication No. US2022 / 0401661, published on December 22, 2022, entitled “DELIVERY DEVICE WITH PUSH EJECTION,” International Publication No. WO2020 / 264501, published on December 30, 2020, entitled “DELIVERY OF SMALL DROPLETS TO THE RESPIRATORYSYSTEM VIA ELECTRONIC BREATH ACTUATED DROPLET DELIVERY DEVICE,” and International Publication No. WO2020 / 264501, published on November 12, 2020, entitled “ULTRASONIC BREATH ACTUATEDRESPIRATORY DROPLET DELIVERY DEVICE AND METHODS OF USE.” 2020 / 227717, all of which are incorporated herein by reference in their entirety, including by reference to such publications and patent applications cited in the cited disclosures and incorporated by reference or relied upon.

[0014] The present technology implements a mesh that generates droplets by vibrating. The configuration of the mesh and other components can vary, but at least one example is given herein. The present technology implements high frequency vibration of the mesh to generate smaller droplet sizes. The present technology implements high frequency vibration, resulting in smaller droplets for a given mesh size. Higher frequency piezoelectric devices allow the mesh to vibrate at a higher frequency. This results in less liquid passing through each hole in the mesh per vibration because the liquid has less time to flow through the hole. If a low frequency is used, then the liquid will have more time to flow out of the hole continuously. The liquid sprays out of the hole intact and then becomes a droplet. At a higher frequency, less liquid flows out of the hole before the mesh reverses direction and thereby cuts off the flow of liquid. Therefore, the droplets generated are smaller than those generated by a low frequency piezoelectric device. The piezoelectric device operates by receiving a signal, which in turn causes it to vibrate at one or more frequencies. As described herein, the piezoelectric element can be operated to vibrate at a high frequency, thereby producing smaller droplet sizes.

[0015] Using a higher frequency piezoelectric device allows the mesh size to be increased for the same size droplet. This can have at least two benefits. First, the mesh can be produced more easily and the mesh size can be controlled. Second, a larger mesh size can reduce the shear involved in generating the droplets. However, there is a maximum frequency for a given mesh size because the higher the frequency, the more there is a point where the liquid will not be able to pass through the mesh. For example, using past technology, a mesh size of 1.7 microns was required to achieve a droplet size target of 1 micron. This is one of the smaller mesh sizes that can be achieved with existing technology. The present technology can use a mesh size on the order of 2 microns and still achieve a droplet size of 1 micron. Therefore, a larger mesh size can be used and still achieve the same droplet size. It is also important to consider liquid viscosity and surface tension when selecting the mesh size and frequency because these two additional factors will also affect the size of the droplet.

[0016] This technique can be accomplished using a small mesh size to reduce the droplet size. Where shear stress on the liquid is a factor, the mesh size can be increased and the frequency increased to generate small droplets.

[0017] In another example, the mesh size can be as described above, but a different drive mechanism can be used to generate the jet. Instead of the mesh as described above, the piezoelectric transducer can vibrate a horn (also called a vibrating member). The horn can then cause the fluid to be expelled through the mesh, thereby generating a fluid jet.

[0018] The operation of another example can be explained like this: When the horn is pulled back, the horn causes the jet to pause, even though the mesh is still vibrating. Similar behavior is similar to pumping behavior. When the horn is pushed forward, the horn presses the liquid against the mesh. When the horn is pulled back, this pulls the liquid between the horn and the mesh.

[0019] Figure 1 The diagram illustrates the generation of droplets using lower and higher frequencies for a given mesh size. As shown, the lower frequency generates larger droplets compared to the higher frequency. Initially, the liquid leaves the mesh in the form of a jet (slug), which then becomes droplets due to the surface tension of the liquid.

[0020] An example device according to the present technology can be described as follows and Figure 2. The droplet delivery device having a membrane mated with a grid also includes a PZT-based ultrasonic transducer coupled to a vibrating member having a tip portion made of at least one of a grade 5 titanium alloy, a grade 23 titanium alloy, and titanium of about 99% or greater purity. In some embodiments, the tip of the vibrating member includes titanium of about 99% or greater purity sputtered on the outer layer, providing a smooth tip surface configured to contact the lower bottom surface of the membrane, which is opposite to the outer top surface of the membrane closest to the grid to help reduce wear of the membrane and increase the life and operational consistency of the membrane (and possibly the tip portion of the vibrating member). The transducer can be configured to have a desired higher frequency as described above. The vibrating member 1708 and the transducer 26 work in conjunction with the membrane 25 and the grid 22 to aerosolize the fluid 901, which is retained in the reservoir 1200 and supplied to the grid 22 using various methods (e.g., wicking materials, hydrophilic coatings, capillary action, etc.). Preferably, the vibrating member is coupled to the transducer such as by bonding (e.g., adhesive, etc.), welding, gluing, physical connection (e.g., brackets and other mechanical connectors), etc. The transducer and the vibrating member interact with the membrane to push the fluid through the grid. As shown and described in various embodiments, the membrane can contact the grid in some cases while also "pushing" the fluid through the holes in the grid, and can be separated without contacting the grid in other cases to push the liquid through the holes in the grid. The transducer may include one or more of various materials (e.g., PZT, etc.). In some embodiments, the transducer is made of lead-free piezoelectric material to avoid the production of unwanted or toxic materials in droplet delivery devices for human inhalation. The vibrating member may be made of one or more of a variety of different materials (e.g., titanium, etc.). The grid may be one or more of a variety of materials (e.g., palladium nickel, polyimide, etc.). After the fluid is pushed through the grid, a droplet spray is formed and ejected through the mouthpiece port, carried by entrained air.

[0021] like Figure 3 As shown in , the body of the second example includes a vibration member and transducer assembly 2603. The vibration member and transducer assembly 2603 is wrapped by a vibration member front cover 2602 and a vibration member rear cover 2604. The covers 2602, 2604 are held together by circular caps called front and rear vibration member cover brackets 2605, 2608. The wrapped vibration member is then placed into a vibration member housing 2601, then into a vibration member assembly spring 2606, and finally seated in a vibration member device bracket 2607. The vibration member housing allows the spring to press the vibration member and transducer assembly onto the membrane.

[0022] Figures 4A-4CAn orifice plate assembly 1200 is illustrated, which includes an orifice plate 1216 (e.g., palladium nickel) supported by a stainless steel ring 1218. The orifice plate is welded or bonded 1220 to the stainless steel ring 1218, thereby together allowing for a thicker support material that is much cheaper than the orifice plate material (e.g., palladium nickel) alone. The stainless steel and orifice plate are bonded 1220 to a piezoelectric material 1222, with all components forming the orifice plate assembly 1200.

[0023] One aspect of the present invention provides an aerosol generation method, comprising: operating an electronic transducer to vibrate at a first frequency; coupling a grid having a predetermined pore size to the electronic transducer; providing a fluid composition to the grid when the transducer vibrates at the first frequency; operating the electronic transducer at a second frequency higher than the first frequency; providing the same fluid composition to the grid when the transducer vibrates at the second frequency; and generating smaller droplets passing through the grid at the second frequency than at the first frequency while maintaining the predetermined pore size.

[0024] In another aspect of the invention, a membrane is coupled between a vibrating member coupled to an electronic transducer and a mesh.

[0025] In another aspect, the methods of the present invention produce inhalable droplets that can be therapeutic, including drugs, biological and pharmaceutical treatments, or can be non-therapeutic, such as simulating smoking, providing flavoring, and the like.

[0026] Another aspect of the present invention includes an aerosol generation method comprising: operating an electronic transducer to vibrate at a first frequency; coupling a mesh having a predetermined pore size to the electronic transducer, wherein the pore size is larger than a desired size of droplets to be produced by the mesh; providing a fluid composition to the mesh while the transducer is vibrating at the first frequency, wherein the fluid comprises at least one of liposomes, other vesicles, and cells; operating the electronic transducer at a second frequency higher than the first frequency; providing the same fluid composition to the mesh while the transducer is vibrating at the second frequency; and generating droplets that experience lower shear in at least a portion of the fluid composition that passes through the mesh pores located in a central region of the mesh.

[0027] In an embodiment of another aspect of the invention, a membrane is coupled between a vibrating member coupled to the electronic transducer and the mesh.

[0028] Although the present invention has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings without departing from the basic scope thereof. Therefore, the present invention is not intended to be limited to the specific embodiments disclosed as the intended best mode for carrying out the present invention, but the present invention will encompass all embodiments within the scope of the appended claims.

Claims

1. An aerosol generation method comprising: operating the electronic transducer to vibrate at a first frequency; coupling a mesh having a predetermined hole size to the electronic transducer; providing a fluid composition to the grid while the transducer is vibrating at a first frequency; operating the electronic transducer at a second frequency higher than the first frequency; providing the same fluid composition to the grid while the transducer is vibrating at a second frequency; as well as While maintaining the predetermined pore size, smaller droplets are generated through the mesh at the second frequency than at the first frequency.

2. The method of claim 1, wherein a membrane is coupled between a vibrating member coupled to the electronic transducer and the mesh.

3. The method of claim 2, further comprising generating inhalable droplets.

4. The method of claim 3, wherein the inhalable droplets are therapeutic.

5. The method of claim 3, wherein the inhalable droplets are non-therapeutic.

6. The method of claim 1, further comprising generating inhalable droplets.

7. The method of claim 6, wherein the inhalable droplets are therapeutic.

8. The method of claim 6, wherein the inhalable droplets are non-therapeutic.

9. An aerosol generating method comprising: operating the electronic transducer to vibrate at a first frequency; coupling a mesh having a predetermined pore size to the electronic transducer, wherein the pore size is larger than a desired size of droplets to be produced by the mesh; providing a fluid composition to the grid while the transducer is vibrating at a first frequency, wherein the fluid comprises at least one of liposomes, other vesicles, and cells; operating the electronic transducer at a second frequency higher than the first frequency; providing the same fluid composition to the grid while the transducer is vibrating at a second frequency; as well as Droplets are generated that experience lower shear in at least a portion of the fluid composition passing through the mesh openings located within a central region of the grid.

10. The method of claim 9, wherein a membrane is coupled between a vibrating member coupled to the electronic transducer and the mesh.

11. The method of claim 10, further comprising generating inhalable droplets.

12. The method of claim 11, wherein the inhalable droplets are therapeutic.

13. The method of claim 11, wherein the inhalable droplets are non-therapeutic.

14. The method of claim 9, further comprising generating inhalable droplets.

15. The method of claim 14, wherein the inhalable droplets are therapeutic.

16. The method of claim 14, wherein the inhalable droplets are non-therapeutic.

Images