JP4765772B2 - 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 (nanosize mist).

  The above charged fine particle water contains radicals and has a long life, can be diffused in a large amount of space, and effectively acts on malodorous substances adhering to indoor walls, clothes, curtains, etc. However, it has a feature that it 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.

  If water for electrostatic atomization is generated on the discharge electrode as condensed water by cooling the discharge electrode, it is not necessary to send water to the discharge electrode. Problems arise. This is because if the discharge electrode is cooled too much, the condensed water will be excessively attached to the discharge electrode, and if the discharge electrode is insufficiently cooled, the condensed water will not be generated on the discharge electrode and atomization will not occur.

  For this reason, the inventors have observed that if the discharge voltage is constant, the discharge current increases when there is a large amount of condensed water, and the discharge current decreases when the amount of condensed water is small. It was proposed to adjust the cooling degree of the cooling means according to the discharge current value. In this case, appropriate dew condensation water is always ensured on the discharge electrode.

However, depending on the environmental temperature and the environmental humidity, the above control may cause the condensed water to freeze (freeze), and there is a demand for a more appropriate control.
Japanese Patent No. 3260150

  The present invention has been invented in view of the above-mentioned conventional problems, and does not require the trouble of replenishing water and is capable of maintaining a stable discharge state for the generation of nano-size mist. An object of the present invention is to provide an atomizing device.

In order to solve the above-mentioned problems, an electrostatic atomizer according to the present invention generates a discharge electrode , a counter electrode opposite to the discharge electrode, and cools the discharge electrode to generate water on the discharge electrode portion based on moisture in the air. A cooling means for applying a high voltage between the two electrodes to generate a discharge between the two electrodes to atomize the water, and monitoring the discharge current and the cooling means according to the discharge current value. In an electrostatic atomizer provided with a control means for controlling the cooling capacity by
In the cooling capacity control according to the discharge current value, the control means regulates the cooling capacity within a range set according to the environmental temperature, and determines that freezing of water on the discharge electrode has occurred from the discharge current value. When the voltage is applied, the voltage application to the cooling means and the high voltage application to the electrodes are stopped for a predetermined time, and the upper limit value of the cooling capacity of the cooling means is reduced by a certain percentage from the previous value when restarting to change the regulation value of the cooling capacity. It has characteristics. By restricting the cooling capacity according to the environmental temperature, it is intended to prevent freezing.

A discharge electrode, a counter electrode opposed to the discharge electrode, a cooling means for cooling the discharge electrode to generate water based on moisture in the air in the discharge electrode portion, and applying a high voltage between the two electrodes In an electrostatic atomizer comprising: a high-voltage power supply for generating a discharge in between to atomize the water; and a control means for monitoring the discharge current and controlling the cooling capacity of the cooling means in accordance with the discharge current value The control means calculates the regulation value of the cooling capacity from the degree of cooling during the stable operation of the atomization and controls the cooling capacity within the range set according to the environmental temperature in controlling the cooling capacity according to the discharge current value. The upper limit value of the cooling capacity of the cooling means at each environmental temperature is stored, and when it is determined from the discharge current value that water on the discharge electrode is frozen, the control value of the cooling capacity is set. You may change to this upper limit .

Further , a high voltage is applied between the discharge electrode, a counter electrode opposite to the discharge electrode, a cooling means for cooling the discharge electrode to generate water based on moisture in the air at the discharge electrode portion, and the two electrodes. Electrostatic atomization provided with a high-voltage power supply for generating a discharge between both electrodes to atomize the water, and a control means for monitoring the discharge current and controlling the cooling capacity of the cooling means according to the discharge current value In the apparatus, the control means calculates the regulation value of the cooling capacity from the degree of cooling during the stable operation of the atomization and controls the cooling capacity according to the discharge current value, and falls within a range set according to the environmental temperature. The cooling capacity is regulated, and a value obtained by adding a predetermined value to the average value of the cooling capacity of the cooling means at each environmental temperature is stored as an upper limit value of the cooling capacity, and the regulation value of the cooling capacity is set to the upper limit value. It may be changed .

  According to the present invention, freezing is not caused in order to regulate the cooling capacity according to the environmental temperature, and an atomization continuous operation that does not cause freezing even in a low temperature environment is possible.

  Hereinafter, the present invention will be described based on an embodiment shown in the accompanying drawings. As shown in FIG. 1, the electrostatic atomizer is configured to face a discharge electrode 2 and one end of the discharge electrode 2 at a predetermined distance. In addition, the counter electrode 3 whose inner peripheral edge functions as a substantial electrode, the high voltage power source 4 that applies a high voltage for discharge between the electrodes 2 and 3, and the other end of the discharge electrode 2 are connected to the heat absorption side. The counter electrode 3 comprises a Peltier module 5 as a cooling means for cooling the discharge electrode 2 to a temperature below the dew point, a power source 6 incorporating a power source 60 for the Peltier module, and a control circuit C. Is grounded, and a negative or positive high voltage (for example, −4.6 kV) is applied to the discharge electrode 2 side during discharge. In the figure, 50 is a heat radiating fin disposed on the heat radiating side of the Peltier module 5, and 8 is an environmental temperature sensor. When referring to environmental humidity, it is assumed that an environmental humidity sensor is also provided.

  As shown in FIG. 2, the high-voltage power supply unit 4 includes a high-voltage generation circuit 40, a discharge voltage detection circuit 41, and a discharge current detection circuit 42. The detected discharge voltage Vv and discharge current Vi are detected by the control circuit C. The control circuit C adjusts the amount of condensed water generated by adjusting the cooling degree of the Peltier module 5 based on the discharge voltage Vv and the discharge current Vi.

  That is, when the discharge voltage is applied between the discharge electrode 2 and the counter electrode 3 in a state where moisture in the air is condensed on the discharge electrode 2 by cooling the discharge electrode 2, the water on the discharge electrode 2 is As shown in FIG. 3, it is pulled toward the counter electrode 3 to have a shape called a tailor cone, and at the tip of the tailor cone, Rayleigh splitting occurs and nanometer-sized charged fine particle water is generated. Atomization is done.

  At this time, if the amount of water on the discharge electrode 2 decreases from the state shown in FIG. 3 (b) and the tailor cone becomes smaller as shown in FIG. 3 (a), the discharge current also decreases, and the amount of water on the discharge electrode 2 decreases. As the number of tailor cones increases as shown in FIG. 3 (c), the discharge current increases. Incidentally, when a discharge voltage of −4.4 kV is applied, the discharge current is 3.0 μA in the state shown in FIG. 3A, the discharge current is 6.0 μA in the state shown in FIG. 3B, and FIG. In the state shown in FIG. 2, the discharge current was 9.0 μA.

  In other words, the shape of the tailor cone is related to the amount of condensed water, and the discharge current also changes from the height of the tailor cone. Therefore, by measuring the discharge current, the height of the tailor cone (condensed water) The amount). Here, if the amount of condensed water on the discharge electrode 2 is further reduced, a discharge occurs between the discharge electrode 2 and the counter electrode 3 instead of a discharge between the water on the discharge electrode 2 and the counter electrode 3. Ozone will be generated. Conversely, if the amount of water on the discharge electrode 2 further increases, the distance between the counter electrode 3 and the water becomes too short, and a large current flows, so that a mist having a target particle diameter cannot be obtained.

  Therefore, here, the amount of water on the discharge electrode 2 is estimated from the discharge current value at a certain discharge voltage, and condensation is achieved by adjusting the cooling degree of the Peltier module 5 which is a cooling means for cooling the discharge electrode 2 based on this estimation. The amount of water generated is adjusted. When the discharge current is small, the applied voltage of the Peltier module 5 is increased to further cool the discharge electrode 2 to increase the amount of condensed water. When the discharge current is large, the degree of cooling is adjusted. The amount of condensed water on the discharge electrode 2 is always suitable for the generation of nano-size mist by performing feedback control in a direction to reduce the amount of condensed water by reducing it. Electrostatic atomization that generates nano-size mist due to is continuously performed without interruption.

  However, if the discharge voltage changes, the discharge current value that represents an appropriate amount of condensed water also changes. Therefore, as shown in Table 1, the optimum discharge current i (n) corresponding to the discharge voltage V (n) The control circuit C controls the duty of the applied voltage of the Peltier module 5 so that the range is defined and the detected discharge current i (n) value is maintained near the median value i (n) typ of the above range. Yes.

  The details of the feedback control based on the discharge current will be described. At time ta when the time Δt until each circuit is stabilized has elapsed, the control circuit C receives the discharge voltage value and the discharge current value from the discharge voltage detection circuit 41 and the discharge current detection circuit 42. The discharge current value upper limit i (n) max and target value (median value) i (n) typ of the discharge current control based on the above-mentioned Table 1 is calculated based on the discharge voltage value obtained by calculating the average value at regular intervals. The lower limit i (n) min is obtained, and the applied voltage applied to the Peltier module 5 is feedback-controlled by duty control so that the measured discharge current i (n) value becomes the target value i (n) typ. Here, in order to avoid overshoot, it is processed as follows.

That is, as shown in FIG. 4, the average values v (1) and i (1) of the discharge voltage value and the discharge current value started to be captured at time ta are determined at time tb after Δt time, and further captured at time tb. When the average value v (2), i (2) of the started discharge voltage value and discharge current value is determined at time tc after Δt time, the difference Δi ( 2) = i (2) −i (1) is calculated, the discharge voltage v (1) at time tb and the target discharge current median value ityp (1) at time tc determined from Table 1 and time The difference Δid (2) from the discharge current value i (2) at tc is obtained, and when the duty of the applied voltage of the Peltier module 5 between time tb-tc is D (2), this duty D (2 ) Increment ΔD (2) from ΔD (2) = a × Δid (2) −b × Δi (2)
(A and b are parameters)
D (3) = D (2) + ΔD (2) is used as the duty of the applied voltage of the Peltier module 5 between the next times tc-td, and is repeated sequentially after each time Δt. ΔD (n) = a × Δid (n) −b × Δi (n)
Is obtained for each Δt and added to the previous duty D (n−1) to determine the next duty D (n). In addition to the difference Δid (n) between the discharge current value i (n) and the target discharge current median value ityp (n), the difference Δi (n) in the discharge current value is taken into account. Overshoot that tends to occur can be avoided. The duty value D (n) and the increment ΔD (n) referred to here correspond to D _{1 to} D ₂₅₆ obtained by dividing the duty 0 to 100% by dividing into ₂₅₆ .

  Here, in FIG. 5, the horizontal axis represents the environmental temperature, the vertical axis represents the humidity, and the corresponding square number represents the dew point temperature of dew point −2 ° C. The colored area is the dew point below the freezing point. If the environmental temperature is 10 ° C. and the environmental humidity is 40%, it is only necessary to cool to −5 ° C. If calculated from the environmental temperature, it can be condensed by 10 ° C .− (− 5 ° C.) = 15 ° C. You will have enough ability in terms.

  And in the electrostatic atomizer, it is premised that the dew condensation water is controlled in the range where it does not freeze, so if the environmental temperature falls, the necessary Peltier cooling capacity may be low, and it is possible to cool only the amount necessary for that temperature. I can do it. In addition, when the same cooling capacity is provided in all environments, the electrode temperature of the discharge electrode 2 is considerably lower than the freezing point even when driven within the capacity range in a low temperature environment. In some cases, when there was a disturbance from the outside, it would react to this disturbance and lead to freezing.

Therefore, here, the upper limit value of the Peltier applied voltage is set to a value that can obtain the required cooling capacity shown in FIG. 5 according to the environmental temperature (and environmental humidity), that is , the cooling capacity according to the environment is provided. This reduces the risk of icing during control. It is desirable that the upper limit of the Peltier applied voltage for each ambient temperature is around + 5 ° C. If the environmental temperature is 10 ° C., the voltage applied to the electrode cooling is set to a voltage that can cool 10 + 5 = 15 ° C.

FIG. 6 shows changes in the Peltier applied voltage. In the figure, V1 is the upper limit value of the Peltier applied voltage set according to the environment. As shown, the Peltier applied voltage feedback control in accordance with the discharge current value will vary within the range of the voltage value V1 and upper limit continues to be inputted Peltier applied voltage can condensed water under the circumstances However, when the discharge current value is near 0 V, it can be determined that icing has occurred. In this case, since it can be presumed that the environment is still supercooled in that environment, the voltage application to the Peltier module 5 and the high voltage application to the electrode are stopped for a predetermined time when the determination of freezing is made, and then these are stopped. When restarting, it is preferable to lower the upper limit value of the Peltier applied voltage by a certain percentage from the previous value. As a result, freezing of the condensed water can be prevented again. In the control circuit C, the upper limit value of the Peltier applied voltage at each environmental temperature is stored in an internal or external storage device, and the stored upper limit value is updated based on the upper limit value change information at the time of freezing. By doing so, it is possible to operate in a non-freezing state at all times.

  Further, FIG. 7 shows changes in both the Peltier applied voltage V and the discharge current I, and the Peltier applied voltage V is also stabilized at a certain value during the period when the discharge current is stabilized. The stable Peltier applied voltage V is affected by the environmental humidity, and is lower as the environmental humidity is higher and takes a larger value as the environmental humidity is lower. This is because the ease with which condensed water can be produced varies depending on the humidity.

Focusing on this point, here it calculates the average value of the stable Peltier applied voltage definitive in each temperature in the control circuit C, and a value obtained by adding a predetermined value vb on the average value va as the upper limit value of the Peltier applied voltage May be. Also in this case, the condensed water is not cooled more than necessary and freezes. Also in this case, the above upper limit value is stored in an internal or external storage device, and this upper limit value is adopted next time, thereby further reducing the risk of freezing.

  Even at the same humidity, the icing rate changes depending on the temperature, and it is necessary that the value of vb at the high temperature is larger than the value of vb at the low temperature. Needless to say, it is preferable to always set and change the average Peltier applied voltage at each temperature for operation in a non-icing state.

It is a circuit diagram of an example of an embodiment of the invention. It is a block circuit diagram same as the above. (a) (b) (c) is explanatory drawing which shows the state of the tailor cone formed with the dew condensation water on a discharge electrode at the time of discharge. It is explanatory drawing regarding a discharge current feedback same as the above. It is explanatory drawing about Peltier cooling capability. It is a time chart of a Peltier applied voltage. It is a time chart of a Peltier applied voltage and discharge current.

Explanation of symbols

C Control Circuit 2 Discharge Electrode 3 Counter Electrode 4 High Voltage Power Supply 5 Peltier Module

Claims (3)

Discharge electrode and a counter electrode opposed thereto, a cooling means for generating a water based on water in the air to the discharge electrode portion to cool the discharge electrode, both electrodes by applying a high voltage between the both electrodes In an electrostatic atomizer comprising: a high-voltage power supply for generating a discharge in between to atomize the water; and a control means for monitoring the discharge current and controlling the cooling capacity of the cooling means in accordance with the discharge current value ,
In the cooling capacity control according to the discharge current value, the control means regulates the cooling capacity within a range set according to the environmental temperature, and determines that freezing of water on the discharge electrode has occurred from the discharge current value. When it is done, the voltage application to the cooling means and the high voltage application to the electrode are stopped for a predetermined time, and the upper limit value of the cooling capacity of the cooling means is reduced by a certain percentage from the previous value when restarting, and the regulation value of the cooling capacity is changed. Electrostatic atomizing device characterized. A discharge electrode, a counter electrode opposed to the discharge electrode, a cooling means for cooling the discharge electrode to generate water based on moisture in the air in the discharge electrode portion, and applying a high voltage between the two electrodes In an electrostatic atomizer comprising: a high-voltage power supply for generating a discharge in between to atomize the water; and a control means for monitoring the discharge current and controlling the cooling capacity of the cooling means in accordance with the discharge current value ,
In the cooling capacity control according to the discharge current value, the control means calculates a regulation value of the cooling capacity from the cooling degree during the stable operation of the atomization, and sets the cooling capacity within a range set according to the environmental temperature. To regulate,
The upper limit value of the cooling capacity of the cooling means at each environmental temperature is stored, and when it is determined from the discharge current value that the water on the discharge electrode is frozen, the regulation value of the cooling capacity is changed to the upper limit value. An electrostatic atomizer characterized by . A discharge electrode, a counter electrode opposed to the discharge electrode, a cooling means for cooling the discharge electrode to generate water based on moisture in the air in the discharge electrode portion, and applying a high voltage between the two electrodes In an electrostatic atomizer comprising: a high-voltage power supply for generating a discharge in between to atomize the water; and a control means for monitoring the discharge current and controlling the cooling capacity of the cooling means in accordance with the discharge current value ,
In the cooling capacity control according to the discharge current value, the control means calculates a regulation value of the cooling capacity from the cooling degree during the stable operation of the atomization, and sets the cooling capacity within a range set according to the environmental temperature. To regulate,
A value obtained by adding a predetermined value to the average value of the cooling capacity of the cooling means at each environmental temperature is stored as an upper limit value of the cooling capacity, and the regulation value of the cooling capacity is changed to the upper limit value. Atomization device.