Methods and apparatus for dispensing liquids as an atomized spray

• US 5,938,117 A
• Filed: 04/05/1995
• Issued: 08/17/1999
• Est. Priority Date: 04/24/1991
• Status: Expired due to Term

• Current Assignee: Novartis Pharma AG (Novartis Ag)
• Original Assignee: Aerogen, Inc. (Nektar Therapeutics)
• Inventors: Ivri, Yehuda
• Primary Examiner(s): Kashnikow, Andres
• Application Number:
  US08/417,311
• Time in Patent Office: 1,595 Days
• Field of Search: 239/102.2, 239/102.1, 239/4, 346/140.1, 346/141, 347/6, 347/9, 347/20, 347/47, 347/68, 347/70
• US Class Current: 239/4
• CPC Class Codes: A61M 11/005 using ultrasonics spraying or atomising liquids using ultrasonic vibrations in general B05B17/06
• CPC Class Codes: A61M 11/006 operated by applying mechanical pressure to the liquid to be sprayed or atomised
• CPC Class Codes: A61M 15/0065 Inhalators with dosage or measuring devices A61M15/0028 takes precedence; dosage devices incorporated in aerosol cans B65D83/52
• CPC Class Codes: A61M 15/0081 Locking means
• CPC Class Codes: A61M 15/0085 using ultrasonics spraying or atomising liquids using ultrasonic vibrations in general B05B17/06
• CPC Class Codes: A61M 15/025 Bubble jet droplet ejection devices
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3379 Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/3382 Upper level detectors
• CPC Class Codes: A61M 2205/3386 Low level detectors
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: B05B 12/08 responsive to condition of liquid or other fluent material to be discharged, of ambient medium or of target ; responsive to condition of spray devices or of supply means, e.g. pipes, pumps or their drive means
• CPC Class Codes: B05B 17/0646 Vibrating plates, i.e. plates being directly subjected to the vibrations, e.g. having a piezoelectric transducer attached thereto
• CPC Class Codes: B05B 17/0676 Feeding means
• CPC Class Codes: B05B 17/0684 Wicks or the like
• CPC Class Codes: B41J 2/025 by vibration
• CPC Class Codes: B41J 2/04 generating single droplets or particles on demand
• CPC Class Codes: B41J 2202/15 Moving nozzle or nozzle plate

Abstract

The invention provides exemplary methods and apparatus for dispensing liquids as an atomized spray. In one particularly preferably method, a liquid is dispensed as an atomized spray from a vibratable member having a front surface and a rear surface, with the member having at least one tapered hole between the surfaces for dispensing the liquid. The tapered hole has a larger cross-sectional area at the rear surface than at the front surface. The liquid is delivered from a supply container to the rear surface of the vibratable member in an amount sufficient to cover the hole with liquid. The vibratable member is then vibrated to dispense at least a portion of the liquid through the hole and from the front surface. Additional liquid is delivered from the supply container and to the rear surface in volumes that are substantially equal to the volumes dispensed.

Claims

1. A method for dispensing liquid droplets as an atomized spray, the droplets being ejected from a vibratable member having a front surface and a rear surface, the member having at least one tapered hole between the surfaces for dispensing the liquid, wherein the tapered hole has a larger cross sectional area at the rear surface than at the front surface, and wherein the liquid is held in surface tension contact with the large opening of the hole, the liquid being delivered from a supply container, the method comprising:

delivering a discrete volume of liquid from the supply container to the rear surface of the vibratable member sufficient to cover the hole with liquid, wherein the discrete volume of liquid is held to the rear surface of the vibratable member by surface tension contact;

vibrating the vibratable member to dispense at least a portion of the liquid through the hole and from the front surface; and

delivering additional volumes of liquid from the supply container and to the rear surface, with the additional volumes being held in surface tension contact to the rear surface of the vibratable member.

2. The method of claim 1, wherein the additional liquid is delivered to the rear surface of the vibratable member at a rate that is substantially equal to the rate of the liquid being dispensed from the front surface.

3. The method of claim 1, further comprising exchanging preselected volumes of gas with liquid from the supply container to deliver the additional volumes of liquid to the rear surface.

4. The method of claim 3, wherein the preselected volumes of gas are sufficient to replace the volumes of liquid that are delivered from the supply container and to the rear surface.

5. The method of claim 4, further comprising controlling supply of the gas volumes to the supply container by closing and opening a gas vent that is in communication with the supply container.

6. The method of claim 5, wherein the gas vent is closed upon filling of the gas vent with liquid delivered from the supply container upon delivery of the liquid to the rear surface of the vibratable member.

7. The method of claim 6, wherein the gas vent is opened upon transfer of liquid from the gas vent and to the rear surface as liquid is ejected from the vibratable member.

8. The method of claim 1, wherein the vibratable member includes a plurality of holes, and wherein the liquid delivered to the rear surface is sized sufficiently to cover at least some of the plurality of holes until dispensed.

9. The method of claim 1, wherein the vibratable member is vibrated at a frequency at about 20 kHz to 200 kHz to eject the liquid.

10. The method of claim 1, further comprising drawing the liquid delivered from the supply container to the rear surface by capillary action.

11. The method of claim 1, where the liquid is an insecticide and wherein the liquid is dispensed at a rate in the range from about 0.5 cm³ to 2 cm³ per hour.

12. The method of claim 11, wherein the liquid is ejected from the front surface in droplets having a mean size in the range from 3 μ

m to 10 μ

m.

13. The method of claim 1, where the liquid is an air freshener and wherein the liquid is dispensed at a rate in the range from 1 cm³ to 2 cm³ per hour.

14. The method of claim 13, wherein the liquid is ejected from the front surface in droplets having a mean size in the range from 3 μ

m to 10 μ

m.

15. An apparatus for dispensing liquid as an atomized spray, comprising:

a vibratable member having a front surface, a rear surface, and at least one tapered hole extending therebetween, the tapered hole having a larger cross sectional area at the rear surface than at the front surface;

a vibrator to vibrate the vibratable member;

a supply container for holding the liquid to be dispensed;

a delivery system to deliver the liquid from the supply container and to the rear surface of the vibratable member in limited volumes so that the volumes delivered adhere to the rear surface of the vibratable member by surface tension contact; and

a flow regulator for regulating the flow of the liquid from the container and to the rear surface of the vibratable member, the flow regulator allowing for delivery of the liquid in volumes that are substantially equal to the volumes dispensed from the hole in the vibratable member.

16. The apparatus of claim 15, wherein the flow regulator includes a gas vent in fluid communication with the supply container for allowing gas to flow into the supply container in volumes that are sufficient to replace the volumes that are delivered to the rear surface.

17. The apparatus of claim 16, wherein the gas vent is closed when filled with liquid from the supply container and is opened upon transfer of liquid from the gas vent to replace liquid ejected from the vibratable member upon vibration of the vibratable member.

18. The apparatus of claim 17, wherein the means for delivery includes a fluid path extending from the supply container, and wherein the gas vent is in communication with the fluid path.

19. The apparatus of claim 18, wherein the delivery system further comprises a capillary channel in the fluid path.

20. The apparatus of claim 15, wherein the flow regulator regulates the flow of the liquid to the vibratable member at a rate that is substantially equal to the rate of liquid dispensed from the hole.

21. The apparatus of claim 16, wherein the gas vent is distanced from the supply container at a distance sufficient to allow the liquid to be delivered to the rear surface at a rate that is substantially equal to the rate of liquid dispensed from the hole.

22. The apparatus of claim 16, wherein the supply container is at a higher elevation than the gas vent.

23. The apparatus of claim 15, wherein the vibratable member includes a plurality of holes.

24. An apparatus for dispensing liquid as an atomized spray, comprising:

a housing having an ejection port;

a vibratable member within the housing, the vibratable member having a front surface, a rear surface, and at least one tapered hole extending therebetween, the tapered hole having a larger cross sectional area at the rear surface than at the front surface, the tapered hole being aligned with the ejection port;

a delivery system to deliver liquid to the rear surface of the vibratable member in limited volumes so that the volumes delivered adhere to the rear surface by surface tension contact; and

a vibrator in the housing for vibrating the member to elect the liquid through the tapered hole.

25. The apparatus of claim 24, further comprising a liquid supply container connected to the housing for holding the liquid to be dispensed.

26. The apparatus of claim 25, further comprising a flow regulator for regulating the flow of the liquid from the container and to the vibratable member, the flow regulator allowing for delivery of the liquid in volumes that are substantially equal to the volumes dispensed from the hole in the vibratable member.

27. The apparatus of claim 26, wherein the flow regulator regulates the flow of the liquid to the vibratable member at a rate that is substantially equal to the rate of liquid dispensed from the hole.

28. The apparatus of claim 24, wherein the vibrator comprises an ultrasonic transducer powered by a battery.

29. The apparatus of claim 28, further comprising a controller within the housing for controlling actuation of the transducer.

30. The apparatus of claim 29, wherein the controller is preprogrammed to cyclically actuate the transducer.

31. The apparatus of claim 26, wherein the supply container is elevated above the flow regulator.