Methods and apparatus for controlling piezoelectric vibration

A method for aerosolizing a liquid, comprising:

• providing an aerosol generator comprising a plate having a plurality of apertures therein and a piezoelectric element disposed to vibrate the plate;
• supplying a liquid to the plate;
• energizing the piezoelectric element to vibrate the plate at an initial frequency;
• adjusting energization of the piezoelectric element to vibrate the plate at a desired frequency during aerosolization of the liquid through the plurality of apertures;
• and
• monitoring a parameter indicative of instantaneous resonant frequency to detect any rapid change in instantaneous resonant frequency.

A method of controlling piezoelectric vibration in an apparatus comprising a piezoelectric vibrating element and a vibratable structure to which the piezoelectric vibrating element is attached, the method comprising:

• energizing the piezoelectric vibrating element to vibrate the vibratable structure at a first frequency;
• detecting a first value of an electrical characteristic of the piezoelectric vibrating element at the first frequency;
• energizing the piezoelectric vibratable element to vibrate the vibratable structure at a second frequency, the first and second frequencies differing from each other by a predetermined amount;
• detecting a second value of the electrical characteristic of the piezoelectric vibrating element at the second frequency;
• comparing the first and second values of the electrical characteristic;
• and
• energizing the piezoelectric element at a third frequency, the second and third frequencies differing from each other by a variable amount dependent upon the comparison made between the first and second values of the electrical characteristic.

A method of determining degradation of a piezoelectric vibration device, the method comprising:

• at a first time, determining a first resonant frequency of the a piezoelectric vibration device;
• at a second time, determining a second resonant frequency of the a piezoelectric vibration device;
• and
• comparing the first and second resonant frequencies to determine a difference, wherein the difference indicates degradation in the piezoelectric vibration device, wherein the degradation in the piezoelectric vibration device includes a crack in the piezoelectric vibration device;
• wherein the first and the second resonant frequencies are determined when the piezoelectric vibration device is not loaded with fluid.

A method of determining degradation of a piezoelectric vibration device, the method comprising:

• at a first time, determining a first resonant frequency of the a piezo electric vibration device;
• at a second time, determining a second resonant frequency of the a piezoelectric vibration device;
• and
• comparing the first and second resonant frequencies to determine a difference, wherein the difference indicates degradation in the piezoelectric vibration device, wherein the degradation in the piezoelectric vibration device includes a clog in the piezoelectric vibration device.

A method for aerosolizing a liquid, comprising:

• providing an aerosol generator comprising a plate having a plurality of apertures therein and a piezoelectric element disposed to vibrate the plate;
• supplying a liquid to the plate;
• energizing the piezoelectric element to vibrate the plate at an initial frequency;
• adjusting energization of the piezoelectric element to vibrate the plate at a desired frequency during aerosolization of the liquid through the plurality of apertures;
• and comparing a parameter indicative of an instantaneous resonant frequency with a predetermined range of values.

A method for aerosolizing a liquid, comprising:

• providing an aerosol generator comprising a plate having a plurality of apertures therein and a piezoelectric element disposed to vibrate the plate;
• supplying a liquid to the plate;
• energizing the piezoelectric element to vibrate the plate at an initial frequency;
• adjusting energization of the piezo electric element to vibrate the plate at a desired frequency during aerosolization of the liquid through the plurality of apertures, the desired frequency being an instantanteous frequency of the plate.

A method of aerosolizing a fluid for inhalation, comprising:

• providing an aerosolizing device having an aerosolizing element, the aerosolizing element being vibrated to aerosolize a fluid, the aerosolizing device having a mouthpiece through which a user inhales aerosolized fluid;
• vibrating the aerosolizing element at a resonant frequency;
• measuring a first parameter related to the resonant frequency of the aerosolizing element during the vibrating step;
• delivering a volume of the fluid to the aerosolizing element;
• aerosolizing the fluid by vibrating the aerosolizing element, the aerosolized fluid being delivered to the user through the mouthpiece;
• measuring a second parameter related to the resonant frequency after initiating the aerosolizing step;
• and
• determining when the volume of fluid has been delivered by comparing the first and second parameters.