Ultrasonic liquid atomizer with an improved soft start circuit
First Claim
1. An apparatus for use with an ultrasonic liquid atomizer having a liquid chamber for holding liquid therein and a piezoelectric vibrator for generating pressure rises in said liquid in response to ultrasonic energy, comprising:
- power supply means connected in use to a mains supply for generating a full-wave rectified supply voltage and a bias voltage;
an oscillator having a transistor connected to be biased by said bias voltage and a resonant circuit a part of which is formed by said piezoelectric vibrator, said transistor and said resonant circuit being connected to receive said full-wave rectified supply voltage to generate said ultrasonic energy in said piezoelectric vibrator in the presence of said bias voltage;
a soft start circuit connected in circuit between said power supply means and said transistor for periodically interrupting the supply of said bias voltage to said transistor for variable lengths of time during an initial brief interval from the time said bias voltage is applied to said transistor so that the ultrasonic energy occurs in a series of bursts which increase gradually in duration as a function of time during said initial brief interval; and
a bias stabilizer effective upon the termination of said initial brief period for preventing said soft start circuit from responding to an unwanted voltage generated by said oscillator.
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Accused Products
Abstract
In an ultrasonic liquid atomizer, an oscillator has a transistor and a resonant circuit a part of which is formed by a piezoelectric vibrator mounted in an energy transfer relationship with liquid in a chamber. The transistor and the resonant circuit receive a full-wave rectified supply voltage to generate ultrasonic energy in the vibrator in the presence of a bias voltage. A soft start circuit has a time constant circuit responsive to the bias voltage and a transistor responsive to an output of the time constant circuit which provides switching action in phase with the full-wave rectified supply voltage so that ultrasonic energy is generated in the form of a series of bursts having durations gradually increasing as a function of time during an initial brief interval from application of the bias voltage to the oscillator. A bias stabilizer has a second time constant circuit responsive to the bias voltage and a transistor connected to the output of the second time constant circuit to establish a low impedance path across the base and emitter of the transistor of soft start circuit after termination of the initial brief interval.
365 Citations
18 Claims
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1. An apparatus for use with an ultrasonic liquid atomizer having a liquid chamber for holding liquid therein and a piezoelectric vibrator for generating pressure rises in said liquid in response to ultrasonic energy, comprising:
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power supply means connected in use to a mains supply for generating a full-wave rectified supply voltage and a bias voltage; an oscillator having a transistor connected to be biased by said bias voltage and a resonant circuit a part of which is formed by said piezoelectric vibrator, said transistor and said resonant circuit being connected to receive said full-wave rectified supply voltage to generate said ultrasonic energy in said piezoelectric vibrator in the presence of said bias voltage; a soft start circuit connected in circuit between said power supply means and said transistor for periodically interrupting the supply of said bias voltage to said transistor for variable lengths of time during an initial brief interval from the time said bias voltage is applied to said transistor so that the ultrasonic energy occurs in a series of bursts which increase gradually in duration as a function of time during said initial brief interval; and a bias stabilizer effective upon the termination of said initial brief period for preventing said soft start circuit from responding to an unwanted voltage generated by said oscillator. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for use with an ultrasonic liquid atomizer having a liquid chamber for holding liquid therein and a piezoelectric vibrator for generating pressure rises in said liquid in response to ultrasonic frequency energy, comprising:
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power supply means connected in use to a mains supply for generating a full-wave rectified supply voltage and a bias voltage with respect to a reference point; an oscillator having a first transistor connected to be biased by said bias voltage and a resonant circuit a part of which is formed by said piezoelectric vibrator, said transistor and said resonant circuit being connected to receive said full-wave rectified supply voltage to generate said ultrasonic energy in said piezoelectric vibrator in the presence of said bias voltage; and a soft start circuit including a first time constant circuit connected to said power supply means and a second transistor biased by the output of said time constant circuit, said second transistor providing switching action in phase with said full-wave rectified supply voltage so that the ultrasonic energy is generated in the form of a series of bursts having durations gradually increasing as a function of time during an initial brief interval from application of said bias voltage to said oscillator. - View Dependent Claims (7, 8, 9)
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10. A combination comprising:
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an ultrasonic liquid atomizer having a liquid chamber for holding liquid therein and a piezoelectric vibrator for generating pressure rises in said liquid in response to ultrasonic energy and atomizing the liquid; voltage supply means connected in use to a mains supply and generating therefrom a full-wave rectified voltage; an oscillator having a bias terminal for generating said ultrasonic energy supplied with said full-wave rectified voltage; first means for periodically interrupting the supply of said full-wave rectified voltage to the bias terminal of said oscillator for variable lengths of time during an initial brief interval from application of said full-wave rectified voltage to the bias terminal of said oscillator so that the ultrasonic energy is generated in the form of a series of bursts which increase gradually in duration as a function of time during said initial brief interval; and second means effective upon the termination of said initial brief interval for preventing said first means from being affected by an unwanted voltage generated said oscillator. - View Dependent Claims (11)
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12. A combination comprising:
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an ultrasonic liquid atomizer having a liquid chamber for holding liquid therein and a piezoelectric vibrator for generating pressure rises in said liquid in response to ultrasonic energy; a power circuit connected in use to a mains supply for generating a full-wave rectified supply voltage; a bias circuit connected to said power circuit for generating a bias voltage; an oscillator having a first transistor connected to be biased by said bias voltage and a resonant circuit a part of which is formed by said piezoelectric vibrator, said transistor and said resonant circuit being connected to receive said full-wave rectified supply voltage to generate said ultrasonic energy in said piezoelectric vibrator in the presence of said bias voltage; and a soft start circuit including a first time constant circuit connected to said bias circuit and a second transistor connected to be powered by said bias voltage and biased by the output of said time constant circuit, said second transistor providing switching action in phase with said fullwave rectified supply voltage so that the ultrasonic energy is generated in the form of bursts whose durations gradually increase as a function of time during an initial brief interval from application of said bias voltage to said oscillator. - View Dependent Claims (13, 14)
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15. An apparatus for use with an ultrasonic liquid atomizer having a liquid chamber for holding liquid therein and a piezoelectric vibrator for generating pressure variations in said liquid in response to ultrasonic energy, comprising:
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an oscillator having a power supply terminal and a resonant circuit including said piezoelectric vibrator, a power supply circuit for supplying gradually increasing and decreasing voltage variations to said power supply terminal, and means operative only during a brief period after initial operation of said oscillator for sequentially preventing and enabling conduction of said oscillator and for progressively increasing conducting intervals of said oscillator during said brief period. - View Dependent Claims (16, 17, 18)
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Specification