JP4581561B2 - Electrostatic atomizer - Google Patents

Description

  The present invention relates to an electrostatic atomizer, and more particularly to an electrostatic atomizer for generating nano-size mist.

  By applying a high voltage between the discharge electrode to which water is supplied and the counter electrode to cause discharge, nanometer-sized charged fine particles are generated by causing Rayleigh splitting in the water held by the discharge electrode and atomization. There are electrostatic atomizers that produce water.

  The above charged fine particle water (nano-size mist) contains radicals and has a long life, can diffuse a large amount into the space, and has a bad odor component attached to indoor walls, clothes, curtains, etc. It has the characteristics that it can act effectively and can be non-brominated.

However, in the case of supplying water in the water tank to the discharge electrode by capillary action, the user is forced to replenish the water tank. In order to make this effort unnecessary, it is conceivable to provide a heat exchange part that generates water by cooling the air, and send water (condensation water) generated in the heat exchange part to the discharge electrode. It takes at least several minutes to generate condensed water in the heat exchange section and send this water to the discharge electrode.
Japanese Patent No. 3260150

  The present invention was invented in view of the above-described conventional problems, and an electrostatic atomizer capable of generating nano-sized mist quickly and appropriately without the need for water supply. The issue is to provide.

In order to solve the above-described problems, an electrostatic atomizer according to the present invention includes a discharge electrode and a counter electrode opposed to the discharge electrode, cools the discharge electrode, and supplies water to the discharge electrode portion based on moisture in the air. And a control means for controlling the cooling temperature of the discharge electrode by the cooling means in accordance with the environmental temperature and the environmental humidity, and the control means detects the temperature of the discharge electrode to obtain the environmental temperature and the environmental humidity. The cooling temperature is feedback-controlled to a temperature range below the dew point determined accordingly and freezing . In order to cool the discharge electrode to an appropriate temperature according to the current environmental temperature and environmental humidity, water for electrostatic atomization is appropriately generated on the discharge electrode.

In particular, since the above-mentioned control means is for feedback controlling the temperature range of the cooling temperature no freezing and a dew point less determined according detect and the environmental temperature and environmental humidity the temperature of the discharge electrode, atomization The generation of the dew condensation water for the purpose is to be made continuously and stably.

  When the control means operates the cooling means at a high output at the start of cooling of the discharge electrode and cools the cooling means to the temperature maintaining operation when it is cooled to a predetermined temperature, the generation of water for atomization is promptly generated. Can be done.

  At this time, if the predetermined temperature is a temperature that should be maintained according to the environmental temperature and the environmental humidity, condensation can be achieved at the highest speed, and the predetermined temperature should be maintained according to the environmental temperature and the environmental humidity. If the temperature is higher than the temperature, the overshoot can be reduced.

  If the cooling temperature of the discharge electrode is given in advance in a table corresponding to the environmental temperature and the environmental humidity, the temperature can be easily controlled.

  Further, if the cooling temperature of the discharge electrode is obtained based on a mathematical expression having the environmental temperature and the environmental humidity as functions, more precise temperature control can be performed.

  The cooling temperature of the discharge electrode has been corrected to allow for temperature measurement errors and temperature gradients, so that more accurate temperature control can be performed, reliable generation of condensed water and excessive condensed water Can be prevented.

  In addition, the control means may cool the discharge electrode to the cooling temperature based on a cooling endotherm preset with respect to the cooling temperature. A temperature sensor for detecting the temperature of the discharge electrode is not required.

  And if a control means stops operation | movement with respect to the environmental conditions used as icing, useless apparatus operation can be avoided.

  Further, if the control means causes discharge between the discharge electrode and the counter electrode only under the condition that dew condensation occurs on the discharge electrode, a useless discharge state can be avoided.

In order to cool the discharge electrode to an appropriate temperature according to the current environmental temperature and environmental humidity, the present invention can appropriately generate water for electrostatic atomization on the discharge electrode. In particular, it is possible to supply dew condensation water continuously and stably to the discharge electrode, so that the trouble of replenishing water is unnecessary, and the generation of nano-size mist is performed quickly and appropriately. Can do.

  Hereinafter, the present invention will be described based on an embodiment shown in the accompanying drawings. FIG. 4 shows an electrostatic atomizing unit 1 in an electrostatic atomizing apparatus according to the present invention, and a cylindrical case 10 has a tip. Is disposed in the opening of the cylindrical case 10, and a counter electrode 3 having a ring shape and an inner peripheral edge serving as a substantial electrode is disposed in the opening of the cylindrical case 10. The counter electrode 3 is connected to a high-voltage power supply 4 for discharge. The counter electrode 3 is grounded, and a high voltage of, for example, −5.5 kV is applied to the discharge electrode 2 side during discharge.

  Further, the heat absorption side of the Peltier module 5 as a cooling means for cooling the discharge electrode 2 is provided connected to the discharge electrode 2. In the figure, 50 is a heat radiation fin disposed on the heat radiation side of the Peltier module 5, and 6 is a power source for the Peltier module.

  In addition, a temperature sensor S3 for measuring the temperature of the discharge electrode 2 is provided, and a temperature sensor S1 and a humidity sensor S2 for measuring environmental temperature and environmental humidity are provided outside the case 10.

  FIG. 3 shows the entire electrostatic atomizing apparatus provided with the electrostatic atomizing unit 1. In FIG. 3, reference numeral 7 denotes a heat dissipating fan that sends air to the heat dissipating fins 50 to promote heat dissipation, and 8 denotes the above-described high-pressure for discharging. A circuit board on which a control circuit C for controlling the operation of the power supply 4 and the power supply 6 for the Peltier module is mounted. On the circuit board 7, a plurality of light emitting portions L1 to L4 for operation display are provided. .

  FIG. 2 shows a circuit block. The control circuit C is connected to an environmental condition determination unit to which the sensors S1 to S3 are connected, a Peltier module control unit to which a Peltier module (power source) is connected, and a discharge unit (discharge high-voltage power supply 4). The control circuit C includes a table (table below) relating to the temperature (cooling temperature) of the discharge electrode 2 to be set for the combination of the environmental temperature Th and the environmental humidity Rh. See). The cooling temperatures Ta, Tb, and Tc in the following table are in a relationship of Ta <Tb <Tc, for example, the cooling temperature Ta = −4 to −2 ° C., and “↑” in the table is lower than the lower column. High temperature, “→ ↑” indicates that the temperature is higher than the left column and the lower column. Actually, there is a certain temperature or a certain temperature range that is lower than the dew point and does not freeze. Has been written. The blank column indicates an area where the Peltier module 5 is turned off for the reason of freezing without condensation.

  Incidentally, the above table is set based on the data of the required heat absorption amount with respect to the electrode cooling temperature in the Peltier module 5 used (see FIG. 5), in which A1 indicates the dew region and A2 indicates the icing region. Although the boundary of both is set to -1 degreeC here, it can be handled as the condensation area | region A1 to -4 degreeC.

  Now, if a start switch (not shown) for electrostatic atomization by the electrostatic atomizer is turned on, the control circuit C determines the environmental temperature Th and the environmental humidity Rh as shown in FIG. The data of the cooling temperature corresponding to the environmental temperature Th and the environmental humidity Rh obtained are acquired from the table. At this time, if the table is blank, the Peltier module 5 is turned off and the discharge is also turned off, and the light emitting portion L2 of the humidification warning indicating that humidification is necessary is turned on and electrostatic atomization is in progress. The light emitting unit L1 for displaying is turned off.

  If the table is not blank, the control circuit C operates the Peltier module 5 to cool it until the temperature of the discharge electrode 2 detected by the temperature sensor S3 reaches the temperature written in the table. If the temperature written in the table is reached, the temperature of the discharge electrode 2 will be within the range of the set temperature ± 10% written in the table (this range is an example and the present invention is not limited to this). Alternatively, when the temperature range is written in the table, the voltage applied to the Peltier module 5 is feedback-controlled based on the output of the temperature sensor S3 so that it falls within the temperature range, and the discharge electrode 2 and the counter electrode 3 And the light emission part L2 for indicating that the humidification is necessary is turned off, and the light emission part L1 is displayed to indicate that electrostatic atomization is in progress. Do.

  The control circuit C repeats the above control to always ensure water on the surface of the discharge electrode 2 which causes condensation on the surface of the discharge electrode 2 and is not too much and too little. Since no water is secured on the surface of the discharge electrode 2 by dew condensation, electrostatic atomization due to discharge is continuously performed without interruption.

  In addition to starting the discharge when the temperature of the discharge electrode 2 is cooled to the temperature written in the table as described above, as shown in FIG. 6, the discharge is started when a predetermined time elapses from the above time. Alternatively, as shown in FIG. 7, the discharge may be started when the temperature of the discharge electrode 2 reaches the discharge start temperature. The discharge start temperature here is set in advance for each combination of the environmental temperature and the environmental humidity in the same manner as the cooling temperature.

  Alternatively, the discharge may be started when a predetermined time has elapsed since the cooling of the discharge electrode 2 by the Peltier module 5 was started. In any case, in order to prevent direct discharge to the discharge electrode 2 and to prevent wear of the discharge electrode 2, the discharge is started in a state where it is considered that condensed water is generated on the surface of the discharge electrode 2.

  The cooling of the discharge electrode 2 by the Peltier module 5 will be described in more detail. In cooling the discharge electrode 2 to the cooling temperature read from the table, first, the Peltier module 5 is operated at full power, and the discharge electrode 2 is cooled to the cooling temperature. After the temperature is lowered, the cooling capacity control of the Peltier module 5 is performed by, for example, duty control so that the temperature of the discharge electrode 2 is maintained in the vicinity of the cooling temperature obtained from the table.

  In this duty control, a DC voltage corresponding to the pulse waveform of the PWM output from the control circuit C is output from the DC / DC converter and applied to the Peltier module 5, and the DC voltage is set to 0.5V to 3.0V, for example. It is performed by changing by 0.1V unit between. Note that the cooling capacity may be controlled by controlling the voltage waveform applied to the Peltier module 5 (PWM control).

  FIG. 8 shows an example of control when the upper limit temperature T1 and the lower limit temperature T2 are written in the table for a certain environmental temperature and environmental humidity, and reach the upper limit temperature T1 at the beginning of operation. Up to 98% (or 100%) full power cooling, if lower than the upper limit temperature T1, the duty (Duty) is lowered by one or more steps when lower than the lower limit temperature T2, and within the range of the upper limit temperature T1 and the lower limit temperature T2 If it is located, the duty is increased by one step. In FIG. 9, “a” indicates a cooling period by full power, and “b” indicates a cooling period by duty control.

  Cooling at full power is limited to a temperature T1 + t (t is, for example, 2). When the temperature is lower than the lower limit temperature T2, the duty is reduced by one step, and the temperature is within the range between the upper limit temperature T1 and the lower limit temperature T2 or within the range between the temperature T1 + t and the lower limit temperature T2. If it does, you may perform control which raises a duty one step. FIG. 10 shows a transition example of the temperature of the discharge electrode 2 in this case.

  As shown in FIG. 11, the current duty may be maintained if the temperature T falls within the range of the upper limit temperature T1 and the lower limit temperature T2. Here, the full power cooling under the condition of the upper limit temperature T1 is performed only at the beginning of the operation, and the duty is increased by one step after the second time.

  FIG. 12 shows still another example. Here, at the beginning of the operation, full power cooling with a duty of 98% (or 100%) is performed until the upper limit temperature T1 is reached, and if the temperature T falls within the range between the upper limit temperature T1 and the lower limit temperature T2, the duty is reduced to the lowest only at the beginning. The level is reduced to a level (for example, 1% duty). This is for avoiding overshoot (or reducing the amount of overshoot) lower than the lower limit temperature T2. Once the temperature T falls below the upper limit temperature T1, the duty is increased by one step when T> T1, the duty is decreased by one step when T <T2, and the control shifts to maintain the current duty when T2 <T <T1.

  In addition, as shown in FIG. 13, when the temporary duty value is determined and the temperature T after full power cooling at the start of operation falls within the range of the upper limit temperature T1 and the lower limit temperature T2, the temporary duty value is You may make it drive. The number of times the temperature can be lowered when a voltage is applied to the Peltier module 5 is determined by the Peltier module. For example, as shown in FIG. When the temperature decreases to 15 ° C. when 1.5V is applied, it is sufficient to apply 1.0V to the Peltier module 5 when it is desired to decrease the temperature by 10 ° C. That is, from the temperature difference between the temperature of the discharge electrode 2 at the start of operation and the lower limit temperature T2, the Peltier is used to bring the discharge electrode 2 to a temperature in the range between the upper limit temperature T1 and the lower limit temperature T2 (close to the lower limit temperature T2). Since the voltage to be applied to the module 5 is known in advance, and the relationship between the output of the DC / DC converter and the duty value of the PWM output is also known in advance as shown in FIG. The temporary duty value is determined from the temperature difference between the temperature of the discharge electrode 2 and the lower limit temperature T2, and the temporary duty value is used for driving. In this case, the overshoot that becomes lower than the lower limit temperature T2 as well as the overshoot that becomes higher than the upper limit temperature T1 can be suppressed. Once in a state of driving with a temporary duty value, the duty is increased by one step when T> T1, decreased by one step when T <T2, and the current duty is maintained when T2 <T <T1. Transition.

  In the above control example, when the environmental temperature is within a certain temperature range and the environmental humidity is within a certain temperature range, the temperature of the discharge electrode 2 is kept within a certain temperature range, but more precise control is performed. Of course, you may do it. For example, when the environmental temperature Th, the environmental humidity Rh, the saturated water vapor pressure Ps, the water vapor pressure P, and the correction temperature α (α = 0 to about −3),

Thus, the temperature of the discharge electrode 2 is maintained at the electrode cooling temperature Ts obtained in step (1). The above equation may be converted into a polynomial approximate curve to obtain the electrode cooling temperature Ts. The correction temperature α is an item introduced so as not to be set to a temperature higher than the actual dew point temperature due to variations in sensor input signals and disturbances.

  By the way, the table is also set based on the value obtained by calculating the above formula. When the temperature is in increments of 5 ° C. and the humidity is in increments of about 10%, the temperature is within a certain temperature range (for example, temperatures 30 to 35). Since there are a plurality of dew point temperature curves in 1 ° C. increments at a temperature of 60 ° C. and a humidity of 60 to 70%, the temperature of the lowest dew point temperature curve (in fact, the correction temperature α is added). The temperature is about −2 ° C. lower than the calculated dew point temperature).

  Even when a table is used, for example, the cooling temperature when the environmental temperature is 25 ° C. and the environmental humidity is 30% is T11, the cooling temperature when the environmental temperature is 30 ° C. and the environmental humidity is 30% is T12, the environment A table in which the cooling temperature when the environmental humidity is 40% at a temperature of 25 ° C. is set as T13 and the cooling temperature when the environmental temperature is 30 ° C. and the environmental humidity is 40% as T14 is provided, and the measured environmental temperature is If the temperature is 26 ° C. and the ambient humidity is 34%, the cooling temperature when the ambient temperature is 26 ° C. and the ambient humidity is 34% is obtained from the temperature T11 to T14 by proportional calculation, and the temperature of the discharge electrode 2 is set to this cooling temperature. If maintained, finer control can be performed regarding the control of the amount of condensation. It goes without saying that fine control can be performed even if the temperature increment and humidity increment on the table are reduced to 2 ° C increments and 2% increments, for example. Water generation can be suppressed.

  In addition, the duty ratio may be changed according to the difference between the environmental temperature and the cooling temperature. Since control suitable for environmental conditions can be performed, a stable rise can be obtained.

  By the way, the temperature sensor S3 is for measuring the temperature of the discharge electrode 2, but the temperature sensor S3 composed of a thermistor or the like cannot be directly provided on the discharge electrode 2 to which a high voltage is applied. Therefore, the temperature of the discharge electrode 2 is measured through an insulating plate or the like. In this case, there is a temperature gradient between the discharge electrode 2 and the temperature sensor S3, and this temperature gradient is shown in FIG. 15 (D in the figure is the discharge electrode temperature, and H is the temperature measured by the temperature sensor S3). Thus, it becomes so large that the applied voltage of the Peltier module 5 is enlarged. Therefore, it is preferable that the table is corrected with a temperature correction value considering this point. Since this temperature gradient can be expressed as an equation of a linear approximation line, the electrode cooling temperature may be derived from the equation.

  In each of the above examples, the temperature sensor S3 for measuring the temperature of the discharge electrode 2 is provided, but the temperature sensor S3 is not necessarily required. The cooling endotherm (FIG. 16) with respect to the cooling temperature is obtained in advance, and when cooling the discharge electrode 2 to a certain temperature, the discharge electrode 2 can be cooled to that temperature by cooling based on the cooling endotherm.

  Moreover, although the temperature sensor S1 and humidity sensor S2 which measure environmental temperature and environmental humidity were shown in the electrostatic atomization unit 1, the information of environmental temperature and environmental humidity was received from the external sensor in the control circuit C. It is also possible to transmit it to.

  In addition, it is desirable to provide the control circuit C with a discharge current monitoring unit that monitors the discharge current. In the case where a discharge is generated in the state where there is no condensed water in the discharge electrode 2, this can be detected by an increase in the discharge current, and therefore a discharge stop process can be performed. Incidentally, whether or not the discharge is abnormal in FIGS. 6 and 7 is determined by monitoring the discharge current by the discharge current monitoring unit.

  In addition, when icing occurs on the discharge electrode 2, the discharge current becomes 1 μA or less, and if the icing melts, a large discharge current flows instantaneously. It is also possible to detect whether or not electrostatic atomization is normally performed, and appropriately perform processing when icing occurs (for example, stopping power supply to Peltier module 5 or changing the duty ratio). Can do. In particular, when the icing occurs, the electrostatic atomization stop time can be shortened by performing a process of dissolving and atomizing the ice.

It is a flowchart which shows an example of operation | movement of an example of embodiment of this invention. It is a block circuit diagram same as the above. It is a perspective view same as the above. It is a schematic sectional drawing of an electrostatic atomization unit same as the above. It is explanatory drawing about a dew condensation area | region and an icing area | region. It is a flowchart of an example of an operation | movement same as the above. It is a flowchart of the other example of operation | movement same as the above. It is a flowchart regarding temperature control of a Peltier module same as the above. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing of the other example same as the above. It is a flowchart of the other example of temperature control of a Peltier module same as the above. It is a flowchart of the further another example of the temperature control of a Peltier module same as the above. It is a flowchart of another example of temperature control of a Peltier module same as the above. (a) is explanatory drawing of the relationship between the applied voltage of a Peltier module, and electrode temperature, (b) is explanatory drawing which shows the relationship between a duty and a DC / DC converter output. It is explanatory drawing of the temperature gradient between discharge electrode temperature and a temperature sensor. It is explanatory drawing of cooling temperature and endothermic amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrostatic atomization unit 2 Discharge electrode 3 Counter electrode 5 Peltier module C Control circuit

Claims (10)

A cooling means having a discharge electrode and a counter electrode opposed to the discharge electrode, and cooling the discharge electrode to generate water based on the moisture in the air in the discharge electrode portion; and a cooling means according to the environmental temperature and environmental humidity Control means for controlling the cooling temperature of the discharge electrode, and the control means detects the temperature of the discharge electrode and reduces the cooling temperature to a temperature range below the dew point determined according to the environmental temperature and environmental humidity and freezing. An electrostatic atomizer that performs feedback control . 2. The electrostatic device according to claim 1, wherein the control means operates the cooling means at a high output at the start of cooling of the discharge electrode and shifts the cooling means to a temperature maintaining operation when the discharge means is cooled to a predetermined temperature. Atomization device. The electrostatic atomizer according to claim 2, wherein the predetermined temperature is a temperature to be maintained that is determined according to the environmental temperature and the environmental humidity . The electrostatic atomizer according to claim 2, wherein the predetermined temperature is higher than a temperature to be maintained, which is determined according to the environmental temperature and the environmental humidity . The electrostatic atomizer according to any one of claims 1 to 4, wherein the cooling temperature of the discharge electrode is previously given in a table corresponding to the environmental temperature and the environmental humidity . The electrostatic atomizer according to any one of claims 1 to 4, wherein the cooling temperature of the discharge electrode is obtained based on a mathematical expression having a function of environmental temperature and environmental humidity . 7. The electrostatic atomizer according to claim 5, wherein the cooling temperature of the discharge electrode is corrected in consideration of a temperature measurement error, a temperature gradient, and the like . 2. The electrostatic atomizer according to claim 1, wherein the control means cools the discharge electrode to the cooling temperature based on a cooling endotherm preset with respect to the cooling temperature . The electrostatic atomizer according to any one of claims 1 to 8, wherein the control means stops the operation with respect to an environmental condition that causes icing . The electrostatic atomizer according to any one of claims 1 to 9, wherein the control means causes discharge between the discharge electrode and the counter electrode only under a condition in which dew condensation occurs on the discharge electrode. .

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