Nebulizer vibrating aperture plate drive frequency control and monitoring

Patent metadata

Field	Value
Publication number	US-9956356-B2
Application number	US-201414423046-A
Country	US
Kind code	B2
Filing date	May 23, 2014
Priority date	Jul 24, 2013
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A nebulizer has an aperture plate, a mounting, an actuator, and an aperture plate drive circuit ( 2 - 4 ). A controller measures an electrical drive parameter at each of a plurality of measuring points, each measuring point having a drive frequency; and based on the values of the parameter at the measuring points makes a determination of optimum drive frequency and also an end-of-dose prediction. The controller performs a short scan at regular sub-second intervals at which drive current is measured at two measuring points with different drive frequencies. According to drive parameter measurements at these points the controller determines if a full scan sweeping across a larger number of measuring points should be performed. The full scan provides the optimum drive frequency for the device and also an end of dose indication.

First claim

The invention claimed is:

1. A nebulizer comprising:
a vibrating aperture plate mounted within the nebulizer and driven by an actuator; and
an aperture plate drive circuit coupled to the actuator and having a controller, wherein the controller is configured to measure an electrical drive parameter at each of a plurality of measuring points, each measuring point having a drive frequency, and, based on the values of the parameter at the measuring points, make a determination of optimum drive frequency and also an end-of-dose prediction, wherein the controller is further configured to perform a short scan at which a parameter is measured at each of two or more measuring points with different drive frequencies, and according to drive parameter measurements at these points, determine if a full scan sweeping across a larger number of measuring points should be performed.

2. A nebulizer as claimed in claim 1 , wherein the short scan has fewer than five measuring points.

3. A nebulizer as claimed in claim 1 , wherein the controller is further configured to compare measurements with tolerance ranges, and if a measurement falls outside an associated tolerance range, a full scan is initiated.

4. A nebulizer as claimed in claim 3 , wherein the tolerance ranges are pre-defined.

5. A nebulizer as claimed in claim 1 , wherein the short scan is performed at regular intervals.

6. A nebulizer as claimed in claim 5 , wherein the intervals are sub-second.

7. A nebulizer as claimed in claim 1 , wherein the full scan has a range of 5 to 300 measuring points.

8. A nebulizer as claimed in claim 7 , wherein the full scan has a range of 100 to 300 measuring points.

9. A nebulizer as claimed in claim 1 , wherein if it is determined that a full scan should be performed, performing a full scan, and further wherein the controller is further configured to dynamically determine from the full scan a frequency for at least one of the short scan measuring points.

10. A nebulizer as claimed in claim 9 , wherein the controller is further configured to select a frequency value corresponding to lowest drive current as a frequency for a short scan measuring point.

11. A nebulizer as claimed in claim 10 , wherein said lowest drive current is determined to correspond to a resonant frequency, and a frequency value for the full scan measuring point with lowest drive current is stored for use as a short scan measuring point frequency.

12. A nebulizer as claimed in claim 1 , wherein the parameter is aperture plate drive current.

13. A nebulizer as claimed in claim 1 , wherein the controller is configured to, during a full scan, dynamically perform a plurality of iterations, and in each iteration, compare the measured parameter against a measurement at a previous measuring point to determine end of dose and/or optimum drive frequency.

14. A nebulizer as claimed in claim 13 , wherein the controller is further configured to determine a slope value from the comparison and identify an end of dose when the slope value is above a threshold.

15. A method of operation of a nebulizer comprising a vibrating aperture plate mounted in the nebulizer and driven by an actuator, the actuator being coupled to an aperture plate drive circuit having a controller, wherein the method comprises:
measuring an electrical drive parameter at each of a plurality of measuring points, each measuring point having a drive frequency; and based on the values of the parameter at the measuring points, make a determination of optimum drive frequency and an end-of-dose prediction;
performing a short scan at which a parameter is measured at each of two or more measuring points with different drive frequencies, and according to drive parameter measurements at these points, determining if a full scan sweeping across a larger number of measuring points should be performed.

16. A method as claimed in claim 15 , wherein the short scan has fewer than five measuring points.

17. A method as claimed in claim 15 , wherein the controller compares measurements with tolerance ranges, and if a measurement falls outside an associated tolerance range, a full scan is initiated.

18. A method as claimed in claim 15 , wherein the short scan is performed at regular intervals.

19. A method as claimed in claim 15 , wherein the full scan has in the range of 5 to 300 measuring points.

20. A method as claimed in claim 15 , wherein if it is determined that a full scan should be performed, performing a full scan, and further wherein the controller dynamically determines from the full scan a frequency for at least one of the short scan measuring points, and selects a frequency value corresponding to lowest drive current as a frequency for a short scan measuring point.

21. A method as claimed in claim 20 , wherein said lowest drive current is determined to correspond to a resonant frequency, and a frequency value for the full scan measuring point with lowest drive current is stored for use as a short scan measuring point frequency.

22. A method as claimed in claim 15 , wherein the parameter is aperture plate drive current.

23. A method as claimed in claim 15 , wherein the controller during a full scan, dynamically performs a plurality of iterations, and in each iteration, compares the measured parameter against a measurement at a previous measuring point to determine end of dose and/or optimum drive frequency.

24. A method as claimed in claim 23 , wherein the controller is further configured to determine a slope value from the comparison and identify an end of dose when the slope value is above a threshold.

Assignees

• Stamford Devices Ltd

Inventors

• Grehan Joseph
• Smith Niall

Classifications

• B05B17/0646

  Vibrating plates, i.e. plates being directly subjected to the vibrations, e.g. having a piezoelectric transducer attached thereto · CPC title

• A61M11/001

  Particle size control · CPC title

• A61M2205/3317

  Electromagnetic, inductive or dielectric measuring means · CPC title

• B05B17/0669

  Excitation frequencies · CPC title

• B05B12/004

  comprising sensors for monitoring the delivery, e.g. by displaying the sensed value or generating an alarm (B05B12/08 takes precedence; registering or indicating the condition or the working of machines or other apparatus in general G07C3/00) · CPC title