Electrostatic atomization device

Abstract

An electrostatic atomization device provided with a transformer including primary and secondary coils. A switching element is connected in series to the primary coil. A switching element drive circuit provides the switching element with a pulse signal to perform a switching operation and generate high voltage from the secondary coil. A discharge unit including a discharge electrode performs electrostatic atomization on liquid supplied to the discharge electrode to generate charged fine liquid droplets when high voltage generated by the secondary coil is applied to the discharge electrode. The switching element drive circuit generates a pulse signal having an oscillation frequency set so that the transformer has drooping characteristics that prevent air discharge from occurring between the discharge electrode and ground even when load on the discharge unit varies and prevents the generation of ozone having a predetermined concentration or greater when the liquid undergoes electrostatic atomization.

1 . An electrostatic atomization device comprising:
 a transformer including a primary coil and a secondary coil;   a switching element connected in series to the primary coil of the transformer;   a switching element drive circuit that provides the switching element with a pulse signal to perform a switching operation with the switching element and generate high voltage from the secondary coil of the transformer; and   a discharge unit including a discharge electrode, in which the discharge unit performs electrostatic atomization on liquid supplied to the discharge electrode to generate charged fine liquid droplets when the high voltage generated by the secondary coil is applied to the discharge electrode;   wherein the switching element drive circuit generates a pulse signal having an oscillation frequency set so that the transformer has drooping characteristics that prevent air discharge from occurring at the discharge electrode and prevent ozone having a predetermined concentration or greater when the liquid undergoes electrostatic atomization even when load on the discharge unit varies.   
     
     
         2 . The electrostatic atomization device according to  claim 1 , wherein the discharge unit includes a ground electrode spaced apart by a constant distance from the discharge electrode, the electrostatic atomization device further comprising:
 a rectification circuit connected between the secondary coil of the transformer, the discharge electrode, and the ground electrode, in which the rectification circuit rectifies the high voltage generated by the secondary coil and applies the rectified high voltage between the discharge electrode and the ground electrode.   
     
     
         3 . The electrostatic atomization device according to  claim 1 , wherein the switching element drive circuit includes an oscillation circuit that generates the pulse signal. 
     
     
         4 . The electrostatic atomization device according to  claim 3 , wherein the oscillation circuit includes a comparator. 
     
     
         5 . The electrostatic atomization device according to  claim 1 , wherein the switching element drive circuit includes:
 a fixed resistor and a variable resistor connected in series;   a comparator having an inverting input terminal, a non-inverting input terminal connected to a node between the fixed resistor and the variable resistor, and an output terminal that outputs the pulse signal; and   a capacitor connected to the inverting input terminal of the comparator;   wherein the oscillation frequency is set by adjusting resistance of the variable resistor.   
     
     
         6 . The electrostatic atomization device according to  claim 1 , wherein the switching element drive circuit includes:
 a first fixed resistor and a second fixed resistor connected in series;   a comparator having an inverting input terminal, a non-inverting input terminal connected to a node between the first fixed resistor and the second fixed resistor, and an output terminal that outputs the pulse signal; and   a variable capacitance capacitor connected to the inverting input terminal of the comparator;   wherein the oscillation frequency is set by adjusting capacitance of the variable capacitance capacitor.   
     
     
         7 . The electrostatic atomization device according to  claim 1 , wherein the switching element drive circuit includes:
 a first variable resistor and a second variable resistor connected in series;   a comparator having an inverting input terminal, a non-inverting input terminal connected to a node between the first variable resistor and the second variable resistor, and an output terminal that outputs the pulse signal; and   a variable capacitance capacitor connected to the inverting input terminal of the comparator;   wherein the oscillation frequency is set by adjusting at least one of resistances of the first and second variable resistors and capacitance of the variable capacitance capacitor.   
     
     
         8 . The electrostatic atomization device according to  claim 5 , wherein the switching element drive circuit includes:
 a totem pole drive circuit connected to the output terminal of the comparator, in which the totem pole drive circuit receives the pulse signal from the comparator, amplifies the pulse signal, and provides the amplified pulse signal to the switching element.