HK1125596A - Electrostatic atomizer and food preserving cabinet with electrostatic atomizer - Google Patents

Description

Electrostatic spraying apparatus and food container provided with the same

Technical Field

The present invention relates to an electrostatic spray apparatus having a function of effectively humidifying, and a function of sterilizing, deodorizing, and effectively decomposing harmful substances, and a food container incorporating the electrostatic spray apparatus.

Background

Japanese patent application No.2005-131549A discloses an electrostatic atomizer which generates a mist of charged water particles by a method of atomizing water by energization. The electrostatic spray device causes Rayleigh breakup (Rayleigh break-up) of water at an emission electrode, atomizes the water by the Rayleigh breakup, and then generates a mist of charged water particles of nanometer order. The mist of the charged minute water particles includes radicals, can float in the air for a long time, and can be diffused into the air in a large amount. The mist of the charged minute water particles adheres to a substance in the space where the mist of the charged minute water particles discharges, permeates into the substance and then sterilizes and deodorizes the substance. The mist of charged water particles can humidify the space. However, the mist of the charged minute water particles has a diameter of nanometer order. Even after the electrostatic spray apparatus generates a large amount of mist of charged minute water particles of nanometer order, the electrostatic spray apparatus discharges only a small amount of water. The electrostatic spray apparatus cannot sufficiently humidify the space. In the case where the electrostatic spray apparatus is used in a space where humidification is required, the electrostatic spray apparatus is generally used together with a conventional humidifier that generates water vapor.

Disclosure of Invention

In view of the above problems, the present invention has been made in an effort to provide an electrostatic spray apparatus capable of humidifying a space, as well as decomposing harmful substances, sterilizing the substances, and deodorizing the substances in the space, and also to provide a food container incorporating the same.

The electrostatic spraying apparatus according to the present invention comprises: a liquid carrier having an emitter electrode formed at one end thereof; an opposed electrode disposed in opposed relation to the emitter electrode; a liquid supply device for supplying liquid to the liquid carrying member; and a high-voltage power supply configured to apply a high voltage between the emitter electrode and the opposed electrode so that the liquid supplied to the tip of the emitter electrode is charged to discharge a mist of charged water particles from the tip of the emitter electrode. The liquid supply means includes a pressurizing means configured to apply pressure to the liquid on the emitter electrode to release the mist of the charged water particles having a size in a wide range from a nanometer size of 3nm to 100nm to a micrometer size of 0.1 μm to 10 μm from the tip of the emitter electrode. The high voltage power supply applies a high voltage at the tip of the emitter electrode. The high voltage at the tip of the emitter electrode forms a Taylor cone (Taylor cone) which is formed at the tip of the emitter electrode by surface tension. The high voltage at the tip of the emitter electrode causes the electrical charge to concentrate at the tip of the taylor cone and causes water splitting. Therefore, the mist of the charged minute water particles of nanometer order is mainly generated and released. In addition, the taylor cone formed by the surface tension is subjected to pressure by the pressurizing means. This pressure disturbs the equilibrium in the form of a taylor cone formed by surface tension. For this reason, the liquid in some other portion than the tip of the taylor cone is also split. Thus, mist of charged water particles is generated from some other portion than the tip of the taylor cone. The charged charge is difficult to concentrate at the end of the taylor cone. Thus, the liquid has little energy for disintegration. Thereby, the mist of the charged minute particles of the micrometer order is generated from some other portion than the tip of the taylor cone. In this case, the electrostatic spray apparatus can humidify the space and can decompose harmful substances in the space by the mist of the charged minute water particles of nanometer order emitted simultaneously with the mist of the charged minute water particles of micrometer order, and can sterilize and deodorize the substances in the space by the mist of the charged minute water particles of nanometer order.

Preferably, the liquid carrier is of tubular construction comprising a main tube and a capillary tube extending from the main tube and defining the emitter electrode. The main tube has an inner diameter sufficiently large compared to the inner diameter of the capillary tube so that it does not cause capillary action. The main tube is provided at a rear end thereof with a pressurizing tank defining a liquid supply device so that liquid stored in the pressurizing tank applies pressure to the liquid at the capillary tip. Thus, the emitter electrode of the electrostatic atomizer generates a mist of charged minute water particles of nanometer order and a mist of charged minute water particles of micrometer order. With this arrangement, the pressurizing tank can apply an appropriate pressure to the liquid supplied to the emitter electrode by capillary action and held at the tip of the emitter electrode. Thus, the emitter electrode of the electrostatic atomizer can generate the mist of the charged minute water particles of nanometer order and micrometer order.

In the case where the pressurizing tank is configured to apply a head pressure of the stored liquid to the liquid at the tip of the capillary tube, preferably, the replenishment tank is coupled to the pressurizing tank, and the level sensor is configured to detect a level of the liquid in the pressurizing tank, and the replenishment device is configured to add the liquid from the replenishment tank to the pressurizing tank so that the level of the liquid detected by the level sensor is maintained at a constant level. In this case, the pressurizing tank can apply a constant head pressure to the liquid at the tip of the emitter electrode. Therefore, the emitter electrode of the electrostatic atomizer can generate the mist of the charged minute water particles of nanometer order and micron order having a stable particle size distribution.

Furthermore, preferably, the pressurized tank comprises a piston for pressurizing the liquid. In this case, the pressure tank can apply pressure to the liquid by using the piston without using a supply tank. Thus, the emitter electrode of the electrostatic atomizer can generate a mist of charged minute water particles having a stable particle size distribution.

Preferably, the mist of the charged minute water particles having a size of nanometer order exhibits a particle size distribution having a peak at 3nm to 50nm, and the mist of the charged minute water particles having a size of micrometer order exhibits a particle size distribution having a peak at 0.5 μm to 1.5 μm. The mist of the charged minute water particles of nanometer and micrometer sizes having the aforementioned particle size distribution can sufficiently humidify the space, and can decompose harmful substances, sterilize the substances, and deodorize the substances in the space. In particular, when the electrostatic spray apparatus of the present invention is used for a vegetable compartment of a container, mist of charged minute water particles of micron order having the above-mentioned particle size distribution enters the interior of vegetables through vegetable pores of 100-. Further, the mist of the charged minute water particles of nanometer order decomposes harmful substances such as agrochemicals attached to vegetables, sterilizes the vegetables, and deodorizes the vegetables. In addition, the mist of charged minute water particles of micron order having a peak of particle size distribution of 0.5 μm to 1.5 μm can effectively supply moisture to various vegetables. The particle size distribution described above can be adjusted by varying the pressure. Therefore, it is preferable that a pressure adjusting means is provided for adjusting the pressure applied to the liquid by the pressurizing means.

Further, preferably, the liquid carrying member includes a filter configured to intercept minerals contained in the liquid. When tap water is used as the liquid, the filter traps minerals such as Ca and Mg, and prevents the minerals from being deposited to the emitter electrode. Thus, the emitter electrode can be electrostatically sprayed.

Preferably, the electrostatic spraying device is provided in a food product container. The food container can humidify food in the food container, keep food fresh by the mist of the charged minute water particles of micron order, decompose harmful substances by the mist of the charged minute water particles of nanometer order, sterilize food, and deodorize food in the food container.

Drawings

Figure 1 shows a schematic view of an electrostatic spraying device according to an embodiment of the invention,

figure 2 shows a perspective view of the electrostatic spraying device described above,

figure 3 shows a perspective view of the electrostatic spraying apparatus in a state where the cover is removed,

figure 4 shows a schematic view of an electrostatic spraying device according to another embodiment of the invention,

fig. 5 shows a schematic view of a food product container provided with an electrostatic spraying device according to the invention, an

Fig. 6 shows a graph for explaining the preservation of freshness of leafy vegetables using the electrostatic spray apparatus according to the present invention.

Detailed Description

An electrostatic spraying apparatus according to an embodiment of the present invention will now be explained with reference to the accompanying drawings. As shown in fig. 1, the electrostatic spray apparatus includes: a liquid carrier 10 having an emitter electrode 20 formed at one end thereof, a counter electrode 30, a high voltage power supply 60, and a controller 70. The counter electrode 30 is provided in a facing relationship with the emitter electrode 20. The high voltage power supply 60 is provided so as to apply a high voltage between the emitter electrode 20 and the opposed electrode 30. The controller 70 is configured to control the high pressure value of the applied high pressure. The liquid carrier 10 has a rear end portion connected to the pressurizing tank 40. The pressurizing tank 40 supplies a liquid such as water stored in the pressurizing tank to one end of the emitter electrode through the liquid carrier 10. The pressurizing tank 40 defines a liquid supply means for supplying liquid to the liquid carrier 10 and a pressurizing means for applying pressure to the liquid. The electrostatic spray apparatus of the present embodiment is explained by using water as the liquid. However, the electrostatic spraying apparatus of the present invention can use other liquids than water.

Water is supplied to the emitter electrode and forms a water droplet at the tip of the emitter electrode by surface tension. The high voltage power supply applies a high voltage of, for example, -8kV to the emitter electrode 20, and generates a high voltage electric field between the opposed electrode 30 and the discharge end of the emitter electrode. The high voltage electric field charges the water by electrostatic charges and causes the emitter electrode 20 to discharge a mist of charged water particles. The high voltage applied between the emitter electrode 20 and the opposed electrode 30 generates coulomb force between the opposed electrode 30 and the water held at one end of the emitter electrode 20, thereby forming a taylor cone TC protruding from the surface of the water droplet. Subsequently, the electric charge is concentrated to the end of the taylor cone TC. The electric field density at the tip of the taylor cone becomes large. As the electric field density at the tip of the taylor cone becomes larger, the coulomb force at the tip of the taylor cone becomes larger, thereby developing a large taylor cone TC. When the coulomb force becomes larger than the surface tension W of water, the taylor cone repeatedly splits (rayleigh splitting). Thereby, a large amount of mist of charged minute water particles of nanometer order is generated. The mist of the charged minute water particles of nanometer order is carried by the air current generated by the ion wind flowing from the emitter electrode 20 to the counter electrode 30, and is discharged through the counter electrode 30.

The pressurized tank 40 is supplied with water from the make-up tank 50 by a pump 52. The water level of the pressurizing tank 40 is always controlled to the same level. The pressurizing tank maintained at a level capable of maintaining the same level applies a constant head pressure to one end of the emitter electrode 20. For this purpose, the pressure tank 40 is provided with a level sensor 42. The pump 52 is controlled by the pressure adjusting device 72, thereby maintaining the water level detected by the level sensor 42 at a constant water level. The pressure adjusting device 72 constitutes the controller 70 and controls the pump 52 to generate a pressure value, i.e., a head pressure set by the pressure setting device 80.

The liquid carrier 10 is of tubular construction. The liquid carrier 10 is formed with an emitter electrode 20 at one end thereof, and the emitter electrode 20 is formed as a capillary. The portion of the liquid carrier 10 that spans the pressurizing tank 40 and the emitter electrode 20 is formed to have an inner diameter where no capillary action occurs. Thus, a water head pressure is applied to the water droplets formed at the emitter electrode 20. The inner diameter of the liquid carrier 10 becomes gradually smaller toward one end thereof, which is the capillary tube. Water is supplied to the tip of the emitter electrode through a capillary tube, and forms a water droplet at the tip of the emitter electrode by surface tension. The head pressure is controlled so that it does not prevent the surface tension from beading up. The head pressure is applied to the taylor cone TC formed by the high pressure.

The head pressure is applied to the taylor cone TC having a form maintained by surface tension. By applying a high voltage, some parts of the charge concentration other than the end of the taylor cone surface are also split. The amount of charge of the some portions other than the tip of the taylor cone is smaller than the amount of charge at the tip of the taylor cone. The portions other than the tip of the taylor cone have little energy to break up the water. Therefore, it is considered that the mist of the charged minute water particles of the order of micrometers is mainly generated. Thus, by applying a high voltage to the water held at the tip of the emitter electrode 20 and subjected to the pressure, a mist of charged minute water particles of nanometer order is generated from the tip of the taylor cone TC. Also, the mist of the charged minute water particles of the micron order is generated from some portions other than the tip of the taylor cone TC. The mist of the charged minute water particles of nanometer order and micron order is released into the space in a dispersed state. The emitter electrode 20 continues to be supplied with water by pressure and continuously generates mist of charged water particles.

The mist of the charged minute water particles of nanometer order includes radicals. The radicals decompose harmful substances, sterilize substances in the space, and deodorize substances in the space. The mist of the charged minute water particles of micron order spreads into the space and humidifies the space.

The pressure adjusting means 72 changes the pressure for applying to the emitter electrode 20, thereby adjusting the particle size distribution and the generation amount of the mist of the charged minute water particles of nanometer order and micrometer order. That is, the particle size distribution and the ratio of the generation amount can be selected according to the pressure set by the pressure setting device 80. The emitter electrode 20 is capable of generating a mixed mist including an optimum number of the mist of the charged minute water particles of nanometer order and micrometer order when used.

In the present application, the nanoscale is defined in a range of equal to or greater than 3nm and equal to or less than 100 nm. The micron order is defined in a range exceeding 0.1 μm and equal to or less than 10 μm.

The above-described components constituting the electrostatic spray apparatus are incorporated in the housing 100 shown in fig. 2 and 3. The housing 100 includes a base 110 and a cover 120 covering the base 110. The base 110 holds the liquid carrier 10, the make-up tank 50, and the pump 52 integrated with the pressurized tank 40. The cover 120 holds the opposed electrode 30. The emitter electrode 20 and the opposed electrode 30 are disposed on the outer surface of the casing 100. The housing 100 incorporates the electrical components that make up the high voltage power supply 60, the controller 70 and the pressure setting device 80. The cover 120 is provided with a window 122. A window 122 is provided to check the water level of the replenishment tank 50 made of a transparent material. The supply tank 50 is provided with a cap 54, and water is supplied to the supply tank 50 as needed.

In the electrostatic spraying device according to the invention, the liquid carrier 10 is provided with a filter 12, which filter 12 traps minerals such as Ca and Mg. Therefore, when the electrostatic spray apparatus uses tap water, the filter 12 prevents minerals from being deposited on the emitter electrode 20.

Fig. 4 shows an electrostatic spraying device incorporated into a food container 90, the food container 90 storing food such as vegetables. The food container 90 can decompose harmful substances such as agrochemicals, sterilize foods, and deodorize foods by the mist of the nano-sized charged minute water particles. The food container 90 can maintain proper humidity in the inner space of the food container 90 by the mist of the charged minute water particles of micron order. In particular, in the case of storing vegetables in a food container, a large amount of mist of charged minute water particles of micron order is supplied to vegetable tissues through stomata of the vegetables. Therefore, the food container can keep vegetables fresh.

The food container is provided with a thermostat 92 for maintaining a predetermined temperature. The outer surface of the temperature regulator 92 is provided with a power button 94 and a temperature regulating button 95. The electrostatic spray device M is operated by the power button 94 and discharges the mist of the charged minute water particles of nanometer order and micrometer order into the container 91.

It is known that leaf vegetables cannot keep their freshness by supplying water only to the leaf surface, but can keep their freshness by supplying water to the tissues of the leaves through the stomata of the leaves. The stomata of the leaves of the leaf vegetables are about 100-200 μm long and 10 μm wide. Since the mist of the nano-sized charged minute water particles has an extremely small particle diameter, the mist of the nano-sized charged minute water particles can enter the tissues of the leaves through the stomata of the leaves, but the water necessary for keeping the leafy vegetables fresh cannot be supplied to the leafy vegetables. However, the mist of the charged minute water particles of the micron order has a large amount of water as compared with the mist of the charged minute water particles of the nanometer order. The micron-sized charged water particles can enter the leaf tissue through the stomata of the leaf, can supply a sufficient amount of water to the leaf vegetable tissue, and can maintain the freshness of the leaf vegetable. To this end, the electrostatic spray apparatus incorporated in the food container is adjusted to an appropriate pressure and to an appropriate applied voltage to generate a mist of charged minute water particles of micron order having a particle size distribution peak in a range of equal to or less than 10 μm (preferably, equal to or more than 0.5 μm and equal to or less than 1.5 μm).

In addition, the mist of the charged minute water particles of nanometer order can enter the tissues of the leaf vegetables through the air holes, can decompose harmful substances such as agrochemicals entering the inside of the tissues of the leaf vegetables, can sterilize and deodorize the inside of the tissues of the leaf vegetables, and can decompose harmful substances attached to the leaf vegetables, can sterilize the leaf vegetables, and can deodorize the leaf vegetables. In this case, the pressure and the applied voltage are adjusted to generate the mist of the charged minute water particles of nanometer order having a particle size distribution in a range of equal to or more than 3nm and equal to or less than 50 nm.

Fig. 5 shows the freshness effect (activity effect) of leafy vegetables in a food container incorporating the above electrostatic spray apparatus. In this experiment, wilted rods were prepared as samples and placed in a container 91 with a capacity of 30 liters. The interior of the container 91 is illuminated by a blue light emitting diode as simulated sunlight, maintained at 5 degrees celsius, and maintained at 99% humidity. The electrostatic spray device M is caused to discharge the mist of the charged minute water particles of nanometer order and micrometer order to the container 91 by applying 8kV between the emitter electrode 20 and the opposed electrode 30. The amount of mist of charged minute water particles generated was 2g per hour. Curve X in fig. 5 shows the rate of change of weight of a three day wilted celery pole placed in the container 91. The rate of weight change of the wilted stems increased to 102%. And the freshness of the celery is kept. Meanwhile, a curve Y in fig. 5 shows a process of using the above-described food container 90 without driving the electrostatic spray apparatus. In this case, the weight change rate of celery three days later decreased to 89%, and the celery became more wilted and was no longer fresh.

In addition, experiments were conducted on the decomposition of agricultural fertilizers from leaf vegetables in the above food containers. In this experiment, a petri dish storing fenitrothion (MEP 1ppm, 0.1ml) was placed in a 30 liter capacity container 91 as an example of an agrochemical. The interior of the container 91 is illuminated by a blue light emitting diode as simulated sunlight. The electrostatic spray device M is caused to discharge the mist of the charged minute water particles of nanometer order and micrometer order to the container 91 by applying 8kV between the emitter electrode 20 and the opposed electrode 30. The amount of mist of charged minute water particles generated was 2g per hour. As a result, the removal rate of the agricultural fertilizer after 24 hours was 44%. Therefore, it is apparent that the mist of the charged minute water particles has a good effect of removing the agricultural chemical fertilizer. Further, the amount of radicals generated by the electrostatic spray apparatus was 12. mu.M/L.

Fig. 6 shows another embodiment of an electrostatic spraying device according to the invention. In the present embodiment, the electrostatic spray is provided with a piston 44, which serves as a pressurizing means. For this reason, other configurations and operations are similar to those of the above-described embodiment, and overlapping description is omitted. The piston 44 is provided at the pressurizing tank 40 formed at the rear end portion of the liquid carrier 10. The piston 44 is driven by an actuator 46 and applies pressure to the water supplied from the pressurized tank 40 to the liquid carrier 10. The actuator 46 is controlled by the pressure adjusting means 72, generates a pressure selected by the pressure setting means 80, and applies the pressure to the taylor cone TC formed at the tip of the emitter electrode 20. In the present embodiment, the pressurized tank 40 is defined as a liquid supply device, and the piston is defined as a pressurizing device.

Claims (10)

1. An electrostatic spraying device comprising:

a liquid carrier having an emitter electrode formed at one end thereof;

an opposed electrode disposed in opposed relation to the emitter electrode;

a liquid supply device for supplying liquid to the liquid carrier;

a high voltage power supply configured to apply a high voltage between the emitter electrode and the opposed electrode to charge the liquid supplied to the tip of the emitter electrode to discharge a mist of charged microparticles from the tip of the emitter electrode;

wherein

The liquid supply device includes a pressurizing device configured to apply pressure to the liquid on the emitter electrode to release the mist of the charged minute particles having a size in a wide range between a nanometer size of 3nm to 100nm and a micrometer size of 0.1 μm to 10 μm from the tip of the emitter electrode.

2. The electrostatic spraying apparatus according to claim 1, wherein the liquid carrier is a tubular configuration including a main tube and a capillary tube extending from the main tube and defining the emitter electrode, the main tube having an inner diameter sufficiently large compared with an inner diameter of the capillary tube so as not to cause a capillary action;

the main tube is provided at a rear end thereof with a pressurizing tank defining the liquid supply device, so that the liquid stored in the pressurizing tank applies pressure to the liquid at the capillary tip.

3. The electrostatic spraying apparatus of claim 2, wherein the pressurized canister is configured to apply a head pressure of the stored liquid to the liquid at the tip of the capillary tube.

4. The electrostatic spraying apparatus of claim 3, further comprising:

a make-up tank coupled to the pressurization tank; and

a level sensor configured to detect a level of liquid in the pressurized tank; and

a make-up device configured to add liquid from the make-up tank to the pressurized tank such that a liquid level detected by the level sensor is maintained at a constant level.

5. An electrostatic spraying device according to claim 2, wherein the pressurised canister comprises a piston which pressurises the liquid.

6. The electrostatic spraying apparatus according to claim 1, wherein the mist of the charged minute particles having a size in the micrometer range has a particle size distribution having a peak at 0.5 μm to 1.5 μm.

7. The electrostatic spraying apparatus according to claim 1, wherein the mist of charged fine particles having a size of nanometer order has a particle size distribution having a peak at 3nm to 50nm, and the mist of charged fine particles having a size of micrometer order has a particle size distribution having a peak at 0.5 μm to 1.5 μm.

8. An electrostatic spraying device according to claim 1, wherein pressure regulating means are provided to regulate the pressure applied to the liquid by the pressurising means.

9. The electrostatic spraying apparatus of claim 1, wherein the liquid transport comprises a filter configured to trap minerals contained in the liquid.

10. A food container provided with an electrostatic spraying device as claimed in any one of claims 1 to 9.