Acoustic liquid dispensing apparatus
First Claim
1. A method for acoustically measuring one or more fluid parameters comprising:
- propagating a test waveform from an acoustic transducer through a liquid contained in a container and towards a free surface of the liquid, the test waveform comprising a short burst of acoustic energy generated by a piezoelectric crystal positioned at a proximal end of the acoustic transducer that is focused by a lens positioned at a distal end of the acoustic transducer;
generating a step reflected wave by reflecting a portion of the test waveform off a calibration surface positioned between the acoustic transducer and the free surface, the calibration surface being positioned at a known distance from the lens;
determining a first period of time that corresponds to the time interval for the step reflected wave to travel from the lens to the calibration surface and back to the lens; and
calculating a sound velocity in the liquid by using twice the known distance of the calibration surface from the lens and the first period of time.
2 Assignments
0 Petitions
Accused Products
Abstract
A liquid dispensing apparatus for dispensing droplets of a liquid, and methods for measuring various fluid parameters of the liquid are described. The liquid dispensing apparatus comprises a container having a chamber for holding a liquid. An orifice is positioned at an end of the chamber for dispensing droplets of the liquid, the orifice being configured to retain the liquid in the container if the container is positioned with the orifice facing in a downward direction. An acoustic transducer means is at least partially positioned in the chamber for periodically propagating a focused acoustic beam toward the orifice and through at least some of the liquid while the liquid is contained in the chamber, with the focused acoustic beam being capable of causing a droplet of the liquid to be ejected from the orifice when a free surface of the liquid is within the depth of field of the acoustic transducer means. Fluid parameters that can be measured include the sound velocity in the liquid, liquid level and liquid concentration, liquid acoustic impedance, liquid density and ultrasonic viscosity.
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Citations
8 Claims
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1. A method for acoustically measuring one or more fluid parameters comprising:
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propagating a test waveform from an acoustic transducer through a liquid contained in a container and towards a free surface of the liquid, the test waveform comprising a short burst of acoustic energy generated by a piezoelectric crystal positioned at a proximal end of the acoustic transducer that is focused by a lens positioned at a distal end of the acoustic transducer; generating a step reflected wave by reflecting a portion of the test waveform off a calibration surface positioned between the acoustic transducer and the free surface, the calibration surface being positioned at a known distance from the lens; determining a first period of time that corresponds to the time interval for the step reflected wave to travel from the lens to the calibration surface and back to the lens; and calculating a sound velocity in the liquid by using twice the known distance of the calibration surface from the lens and the first period of time. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for acoustically measuring one or more fluid parameters comprising:
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propagating a test waveform from an acoustic transducer through a liquid contained in a container and towards a free surface of the liquid, the test waveform comprising a short burst of acoustic energy generated by a piezoelectric crystal positioned at a proximal end of the acoustic transducer that is focused by a lens positioned at a distal end of the acoustic transducer; generating a lens reflected wave by reflecting a portion of the short burst of acoustic energy off the lens in the acoustic transducer; generating a step reflected wave by reflecting a portion of the test waveform off a calibration surface positioned between the acoustic transducer and the free surface, the calibration surface being positioned at a known distance from the lens; generating a liquid reflected wave by reflecting a portion of the test waveform off the free surface of the liquid; detecting the lens reflected wave, the step reflected wave and the liquid reflected wave with the piezoelectric crystal; determining a first period of time that corresponds to the time interval between when the lens reflected wave is detected by the piezoelectric crystal and when the step reflected wave is detected by the piezoelectric crystal; determining a second period of time that corresponds to the time interval for the liquid reflected wave to travel from the lens to the free surface and back to the lens; calculating a sound velocity in the liquid by using the known distance of the calibration surface from the lens and the first period of time; and calculating the distance of the free surface from the lens by using the sound velocity in the liquid and the second period of time. - View Dependent Claims (8)
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Specification