Metering system and method for aerosol delivery

• US 9,550,034 B2
• Filed: 08/04/2015
• Issued: 01/24/2017
• Est. Priority Date: 09/25/2003
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Beavis, Russell H., Gray, Larry B., Kane, Derek G.
• Primary Examiner(s): DOUGLAS, STEVEN O
• Application Number:
  US14/817,373
• Publication Number:
  US 20150335835A1
• Time in Patent Office: 539 Days
• Field of Search: 128/200.14, 128/200.18, 128/200.21, 128/200.22, 128/203.12, 128/203.14, 128/205.23, 128/205.24, 128/203.26, 128/200.16, 731/49, 736/49, 732/90.B, 137/565.01, 137/565.34, 261/27
• US Class Current: 1/1
• CPC Class Codes: A61M 15/0003 with means for dispensing more than one drug
• CPC Class Codes: A61M 15/002 with air flow regulating means
• CPC Class Codes: A61M 15/0045 using multiple prepacked dosages on a same carrier, e.g. blisters
• CPC Class Codes: A61M 15/0048 the dosages being arranged in a plane, e.g. on diskettes
• 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 15/0066 with means for varying the dose size
• CPC Class Codes: A61M 15/0068 Indicating or counting the number of dispensed doses or of remaining doses
• CPC Class Codes: A61M 15/008 Electronic counters
• CPC Class Codes: A61M 15/0085 using ultrasonics spraying or atomising liquids using ultrasonic vibrations in general B05B17/06
• CPC Class Codes: A61M 15/009 using medicine packages with incorporated spraying means, e.g. aerosol cans pocket atomiser of the injector type A61M11/08
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2202/03 Gases in liquid phase, e.g. cryogenic liquids
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2205/3379 Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: B05B 12/006 Pressure or flow rate sensors
• CPC Class Codes: B05B 12/085 : responsive to flow or pressure of liquid or other fluent material to be discharged B05B1/3006, B05B1/323, B05B7/1254 take precedence
• CPC Class Codes: G01F 1/007 : by measuring the level variations of storage tanks relative to the time
• CPC Class Codes: G01F 17/00 : Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies measuring linear dimensions to determine volume G01B
• CPC Class Codes: G01F 22/00 : Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
• CPC Class Codes: G01F 23/14 : by measurement of pressure
• CPC Class Codes: G01H 3/00 : Measuring characteristics of vibrations by using a detector in a fluid G01H7/00, G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G10K 9/04 : by compressed gases, e.g. compressed air

Abstract

A method for metering the delivery of a fluid. The apparatus has a variable acoustic source and a microphone, both acoustically coupled to a volume having a fluid region and an air region. The apparatus may also include a processor to determine a volume of the air region based on signals received from the microphone and the variable acoustic source. A fluid valve is coupled to the processor, and is configured to allow an amount of fluid to exit the fluid region associated with the volume of the air region.

Claims

1. A method for metering fluid output comprising:

providing a printed circuit board having a first microphone, a second microphone and an acoustic source

enclosing the printed circuit board with a housing in such a way as to define a first volume of an acoustic system, the acoustic system having a resonant frequency;

mounting a diaphragm covered fluid region against the housing to define an air region between the housing and fluid region, the air region being a part of the acoustic system;

fluidically coupling an output valve to the fluid region;

coupling the first microphone to the first volume;

coupling the acoustic source to the first volume;

coupling the second microphone to the air region;

exciting the acoustic system at a pre-determined frequency with the acoustic source;

receiving a first signal from the first microphone associated with an acoustic response of the first volume to excitement at a pre-determined frequency;

receiving a second signal from the second microphone associated with an acoustic response of the air region to excitement at a pre-determined frequency;

determining a volume of the air region associated with the first signal and the second signal; and

controlling the output valve to meter fluid from the fluid region associated with the volume of the air region.

2. The method for metering fluid output of claim 1, further comprising equalizing a pressure between the first volume and the air region through a hole in the printed circuit board.

3. The method for metering fluid output of claim 1, wherein a second volume is defined by the air region and fluid region.

4. The method for metering fluid output of claim 1, further comprising:

measuring a temperature of the acoustic system with a temperature sensor on the printed circuit board; and

further determining the volume of the air region associated with the temperature of the acoustic system.

5. The method for metering fluid output of claim 1, wherein the diaphragm covered fluid region is part of a disposable drug cassette.

6. The method for metering fluid output of claim 1, further comprising:

exciting the acoustic system at a plurality of pre-determined frequencies;

receiving a plurality of signal pairs, a signal pair being a pair of signals from the first and second microphones associated with the acoustic response of the first volume and air region respectively to excitement at a single pre-determined frequency; and

further determining the volume of the air region associated with the plurality of signal pairs.

7. The method of claim 1, further comprising

determining a gain of the second signal relative to the first signal;

determining a phase shift of the second signal relative to the first signal; and

further determining a volume of the air region associated with the gain and phase shift of the second signal relative to the first signal.

8. A method for metering fluid output comprising:

providing a printed circuit board having a first microphone, a second microphone and an acoustic source

enclosing the printed circuit board with a housing in such a way as to define a first volume of an acoustic system, the acoustic system having a resonant frequency;

mounting a diaphragm covered fluid region against the housing to define a second volume, the second volume includes a gas region and a fluid region, the second volume being part of the acoustic system, the fluid region having an output;

fluidically coupling an input valve to the fluid region;

coupling the first microphone to the first volume;

coupling the acoustic source to the first volume;

coupling the second microphone to the second volume;

exciting the acoustic system at a pre-determined frequency with the acoustic source;

receiving a first signal from the first microphone associated with an acoustic response of the first volume to excitement at a pre-determined frequency;

receiving a second signal from the second microphone associated with an acoustic response of the second volume to excitement at a pre-determined frequency;

determining a volume of the air region associated with the first signal and the second signal; and

allowing fluid to enter the fluid region for metering upon output associated with the volume of the air region.

9. The method for metering fluid output of claim 8, further comprising equalizing a pressure between the first volume and the air region through a hole in the printed circuit board.

10. The method for metering fluid output of claim 8, further comprising:

measuring the temperature of a acoustic system with a temperature sensor on the printed circuit board; and

further determining the volume of the air region associated with the temperature of the acoustic system.

11. The method for metering fluid output of claim 8, wherein the diaphragm covered fluid region is part of a disposable drug cassette.

12. The method for metering fluid output of claim 8, further comprising:

exciting the acoustic system at a plurality of pre-determined frequencies;

receiving a plurality of signal pairs, a signal pair being a pair of signals from the first and second microphones associated with an acoustic response of the first volume and air region respectively to excitement at a single pre-determined frequency; and

further determining the volume of the air region associated with the plurality of signal pairs.

13. The method for metering fluid output of claim 8, further comprising

determining a gain of the second signal relative to the first signal;

determining a phase shift of the second signal relative to the first signal; and

further determining the volume of the air region associated with the gain and phase shift of the second signal relative to the first signal.

14. A method for outputting fluid comprising:

providing a printed circuit board having a first microphone, a second microphone and an acoustic source

enclosing the printed circuit board with a housing in such a way as to define a reference volume of an acoustic system, the acoustic system having a resonant frequency;

mounting a diaphragm covered fluid region against the housing to define a variable volume, the variable volume being part of the acoustic system, the fluid region having an output;

fluidically coupling a valve to the fluid region;

coupling the first microphone to the reference volume;

coupling the acoustic source to the reference volume;

coupling the second microphone to the variable volume;

exciting the acoustic system at a pre-determined frequency with the acoustic source;

receiving a first signal from the first microphone associated with an acoustic response of the reference volume to excitement at a pre-determined frequency;

receiving a second signal from the second microphone associated with an acoustic response of the variable volume to excitement at a pre-determined frequency;

determining the resonant frequency of the acoustic system;

determining a volume of the variable volume associated with the resonant frequency; and

controlling the valve to allow an amount of fluid to exit the fluid region, the amount of fluid being associated with the determined volume of the variable volume.

15. The method for outputting fluid of claim 14, further comprising equalizing a pressure between the reference volume and the variable volume through a hole in the printed circuit board.

16. The method for outputting fluid of claim 14, further comprising:

measuring a temperature of the acoustic system with a temperature sensor on the printed circuit board; and

further determining the volume of the variable volume associated with the temperature of the acoustic system.

17. The method for outputting fluid of claim 14, wherein the diaphragm covered fluid region is part of a disposable drug cassette.

18. The method for outputting fluid of claim 14, further comprising:

exciting the acoustic system at a plurality of pre-determined frequencies;

receiving a plurality of signal pairs, a signal pair being a pair of signals from the first and second microphones associated with the acoustic response of the reference volume and variable volume respectively to excitement at a single pre-determined frequency; and

further determining the resonant frequency of the acoustic system associated with the plurality of signal pairs.

19. The method for outputting fluid of claim 14, further comprising

determining a gain of the second signal relative to the first signal;

determining a phase shift of the second signal relative to the first signal; and

further determining the resonant frequency of the acoustic system associated with the gain and phase shift of the second signal relative to the first signal.

20. The method for outputting fluid of claim 14, further comprising

modeling the acoustic system as a second order system model;

and

further determining a resonant frequency of the acoustic system associated with the second order system model.

21. The method for outputting fluid of claim 14, further comprising

modeling the acoustic system with an electrical analog model;

and

further determining a resonant frequency of the acoustic system associated with the electrical analog model.

22. The method for outputting fluid of claim 14, further comprising

modeling the acoustic system with a mechanical analog model;

and

further determining a resonant frequency of the acoustic system associated with the mechanical analog model.

23. The method for outputting fluid comprising:

enclosing a printed circuit board within a housing, the printed circuit board including a speaker and a microphone;

defining a volume within the housing, the volume including an air region and a fluid region, the fluid region having a fluid output;

fluidically connecting a valve to the fluid region;

coupling the microphone to the volume;

coupling the acoustic source to the volume;

exciting the air region at a pre-determined frequency with the acoustic source;

receiving a signal from the microphone associated with an acoustic response of the air region to excitement at a pre-determined frequency;

determining a volume of the air region associated with the signal; and

controlling the valve to allow an amount of fluid to exit the fluid region, the amount of fluid being associated with the determined volume of the air region.

24. The method for outputting fluid of claim 23, further comprising:

measuring a temperature of the air region with a temperature sensor on the printed circuit board; and

further determining the volume of the air region associated with the temperature of the acoustic system.