JP2001062342A - Electric precipitator and air conditioner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the outflow of a leaked current to an electric heating wire without lowering the strength of a heating element and to simplify a high voltage generating peripheral circuit while miniaturizing a dust collecting electrode. SOLUTION: High voltage is applied across a discharge electrode 60 and the catalyst layer of a dust collecting electrode 70 to ionize dust contained in air by the discharge current flowing across both electrodes and the ionized dust is attracted to the catalyst layer 79 of the dust collecting electrode 70. The dust collecting electrode 70 is formed by providing the catalyst layer 79 to which a metal oxide or a conductor is added on the outer surface of a metal pipe 75 in which an electric heating wire 76 is inserted through an insulating layer 78 comprising a fluoroplastic resin being an insulating material and, since voltage is applied to the catalyst layer 79, a leak current is prevented from flowing to the electric heating wire 76 from the catalyst layer 79.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric dust collector for collecting dust contained in air to a dust collecting electrode by using a discharging action by a high voltage and an air conditioner using the same.

[0002]

2. Description of the Related Art Conventionally, as an electric dust collector, a deodorizing heater in which activated alumina, silica and zeolite are provided on the surface of a heating element such as a sheathed heater and a catalyst layer made of a platinum group metal is formed on the surface of this adsorption layer is known. Have been. In this deodorizing heater, the odor components and dust contained in the air are adsorbed on the catalyst layer, decomposed and removed by the oxidation promoting action of the catalyst and the heating of the heater, and the adsorption capacity is recovered by self-cleaning. (See, for example, JP-A-6-300307 and JP-A-9-61042).

[0003] An electric precipitator which obtains a dust collection function by a discharge action by applying a high voltage is provided with a discharge electrode and a dust collection electrode, and an oxidation catalyst and a heating element are provided in the dust collection electrode, and a high voltage is applied between these two electrodes. An electric precipitator is known which ionizes dust and fine particles contained in the air by its discharge action and adsorbs the dust and dust on a dust collecting electrode. Also in this electric dust collector,
The dust adsorbed on the dust collection electrode is oxidized and decomposed to remove it.
The dust collection electrode is regenerated by self-cleaning (for example, see Japanese Patent Publication No. 61-36984).

As a dust collecting electrode in the above-described electric dust collector, an electric resistance wire (Nichrome wire) is housed inside a metal tube such as Incoloy or stainless steel (SUS) and filled with an insulating material such as magnesium oxide. (See, for example, Japanese Patent Publication No. 60-40155, Japanese Patent Application Laid-Open No. 8-41655, etc.). In such a dust collector, a high voltage is applied from a high voltage unit between a metal tube serving as a dust collecting electrode and a discharge electrode during a dust collection operation, and a nichrome wire in the metal tube is energized from an AC power supply during self-cleaning. Is made.

[0005]

However, in the conventional dust collecting electrode using a sheathed heater as a base, a high voltage (minus voltage) is applied to the metal tube during the dust collecting operation, so that the discharge current passes through the internal insulating material. Leakage to the nichrome wire.

In order to prevent such a leak phenomenon, there is a technique for increasing the distance between contacts in a primary circuit connected to a nichrome wire (Japanese Patent Application No. 9-359125).
issue). This technology inserts a relay circuit that opens and closes the circuit between the Nichrome wire and the AC power supply circuit, and electrically insulates these Nichrome wires from the AC power supply when high voltage is applied for dust collection operation. This state prevents leakage current from flowing from the metal tube toward the nichrome wire when a high voltage is applied to the metal tube.

However, when such a high-voltage relay circuit is used, a high-voltage generating circuit including the relay circuit is complicated, and a circuit board on which the high-voltage generating circuit is mounted and a mounting space for the circuit board are mounted. However, there is a problem that the number of parts constituting the circuit and the cost of parts increase. Also, as a method of preventing the leakage current from leaking out, it is conceivable to increase the cylindrical diameter of the metal tube of the dust collection electrode to increase the distance between the metal tube and the nichrome wire. As a result, the size of the dust collecting electrode increases, which results in an increase in the size of the electric dust collector.

In order to prevent the leakage current from leaking out without complicating the peripheral circuit for generating a high voltage and increasing the size of the dust collecting electrode, the present applicant has first built in a heater wire. Using a glass tube heater or quartz tube heater made of an electrically insulating material such as glass on the heating element surface, providing a conductor layer and an oxidation catalyst on its outer surface, and using this as a dust collection electrode (Japanese Patent Application No. Hei 10-242251). However, these heaters in which the surface of the heating element is made of an insulator such as glass have a disadvantage in that the strength is weak.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can prevent the leakage current from leaking to the nichrome wire without reducing the strength of the heating element. It is an object of the present invention to provide an electric precipitator capable of simplifying a voltage generation peripheral circuit and downsizing of a precipitating electrode, and an air conditioner using the same.

[0010]

In order to achieve the above object, a first aspect of the present invention provides a discharge electrode to which a high voltage is applied,
A dust collecting electrode provided opposite to the discharge electrode and to which a voltage having a polarity opposite to the high voltage is applied, and a heating wire is inserted into a metal tube as the dust collecting electrode and an electric insulator is filled. An electric precipitator that collects dust contained in the air at the dust collection electrode by using a heating element formed by using a discharge action by applying a high voltage between the two electrodes, wherein the dust collection electrode includes: An outer surface of the metal tube is coated with an insulating material, and a catalyst layer obtained by adding a metal oxide or a conductor to an oxidation catalyst is provided thereon, and the voltage is applied to the catalyst layer. .

In this configuration, when a high voltage is applied between the discharge electrode and the catalyst layer of the dust collection electrode, dust contained in the air is ionized by a discharge current flowing between the two electrodes, and the ionization is performed. The dust is adsorbed on the catalyst layer of the dust collection electrode. Furthermore, when the heating wire is energized for self-cleaning, the temperature of the oxidation catalyst of the dust collection electrode rises, and the adsorbed dust is oxidized and decomposed stepwise by the catalytic action, and finally the dust is converted into carbon dioxide and water vapor. It is a colorless and odorless gas. Here, the collecting electrode is provided with a catalyst layer to which a metal oxide or a conductor is added via an insulating material on the outer surface of the metal tube into which the heating wire is inserted, and a voltage is applied to the catalyst layer. No leak current flows through the heating wire. Therefore, the high voltage generating peripheral circuit can be simplified.

Further, according to the present invention, a discharge electrode to which a high voltage is applied and a dust collecting electrode provided opposite to the discharge electrode and to which a voltage having a polarity opposite to the high voltage are applied are provided. A heating element is used as a dust collection electrode, in which a heating wire is inserted into a metal tube and filled with an electrical insulator, and a discharge action is applied by applying a high voltage between the two electrodes, and the dust collection electrode is introduced into the air. In an electric precipitator that collects dust contained in the dust collecting electrode, the dust collecting electrode covers an outer surface of the metal tube with an insulating material, and further oxidizes the metal tube to a substance whose conductivity increases due to moisture absorption. A catalyst layer made of an oxidation catalyst material to which a substance is added is provided, and the voltage is applied to the catalyst layer. Also in this configuration, an operation equivalent to the above can be obtained.

According to a third aspect of the present invention, in the first or second aspect, the insulating material covering the outer surface of the metal tube is made of a fluororesin. This makes the device resistant to dielectric breakdown.

According to a fourth aspect of the present invention, there is provided a heat exchanger for air conditioning, and an electric dust collector disposed in a ventilation path of air to be heat-exchanged by the heat exchanger and collecting dust contained in the air. In the configured air conditioner, the electrostatic precipitator includes a discharge electrode to which a high voltage is applied, and a dust collection electrode provided to face the discharge electrode and to which a voltage having a polarity opposite to that of the high voltage is applied. A heating element that is formed by inserting a heating wire into a metal tube and filling an electric insulator as the dust collection electrode, and using a discharge action caused by application of a high voltage between the two electrodes to form a dust collector in the air. The outer surface of the metal tube is coated with an insulating material, and a catalyst layer obtained by adding a metal oxide or a conductor to an oxidation catalyst is provided thereon. The above voltage is applied to

In this configuration, dust contained in the air to be conditioned can be collected, and the same operation as in the first aspect can be obtained.

According to a fifth aspect of the present invention, there is provided a heat exchanger for air conditioning, and an electric dust collector disposed in a ventilation path of air to be heat-exchanged by the heat exchanger and collecting dust contained in the air. In the configured air conditioner, the electrostatic precipitator includes a discharge electrode to which a high voltage is applied, and a dust collection electrode provided to face the discharge electrode and to which a voltage having a polarity opposite to that of the high voltage is applied. A heating element that is formed by inserting a heating wire into a metal tube and filling an electric insulator as the dust collection electrode, and using a discharge action caused by application of a high voltage between the two electrodes to form a dust collector in the air. The outer surface of the metal tube is coated with an insulating material, and a catalyst layer obtained by adding a metal oxide to a hygroscopic substance is provided thereon. The above-mentioned voltage is applied. Also in this configuration, an operation equivalent to that of the fourth aspect is obtained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner with an electric dust collector according to one embodiment of the present invention will be described below with reference to FIGS. The air conditioner 1 with an electric dust collector has both an air conditioning function of cooling or heating indoor air and a dust collecting function of removing dust contained in the indoor air and purifying the air. Attached to the wall etc. The air conditioner 1 includes a casing 10 having a front surface opened as an air intake port 11 and an air discharge port 12 provided below the air intake port 11;
1, a front panel 20 attached to the air inlet 11 of the casing 10, and a heat exchanger 30 for air conditioning provided in the casing 10 facing the inlet 11 of the casing 10.
And a cross-flow type fan 40 provided on the back side of the discharge port 12 for flowing air from the suction port 11 to the discharge port 12 via the heat exchanger 30, and a ventilation path on the back side of the heat exchanger 30 And an electric precipitator 50 disposed at the position 31.
A filter 3 is provided between the front panel 20 and the heat exchanger 30.
2, and an outlet 12 of the casing 10 is provided with an angle-adjustable louver 13. A control circuit for controlling the air conditioner 1 is mounted inside the casing 10. The heat exchanger 30 is connected to a heat exchanger of an outdoor unit (not shown) by a refrigerant pipe.

An electric precipitator 50 is provided in parallel with a horizontally extending discharge electrode 60 and a predetermined distance from the discharge electrode 60, and is a rod-shaped dust collector having a built-in heating element for self-cleaning. An electrode 70 and a heat shielding plate 80 that shields heat from the dust collecting electrode 70 and holds the discharge electrode 60 and the dust collecting electrode 70 are provided. The casing 10 is attached to the surface of the vertical back plate 18 so as to face the inside of the road 31.

The discharge wire 61 constituting the discharge electrode 60 is held at both ends by an electrode terminal 63 attached to a holding member 62 via a tension spring 64, and is positioned and fixed by the tension of the tension spring 64. A high voltage is applied to the discharge wire 61 from the electrode 63 through a tension spring 64. The dust collecting electrode 70 is composed of a tube-shaped heating element 71, and is located on the leeward side of the ventilation passage 31 with respect to the discharge electrode 60.
The grips 72 at both ends in the length direction are fixed to a holding member 74 by locking members 73. A terminal fitting 70a serving as an electrode terminal for applying a high voltage to the dust collection electrode 70 is attached to a position near the grip portion 72 on the outer peripheral surface of the heating element 71. A positive DC high voltage and a negative DC high voltage are respectively applied to the discharge electrode 60 and the dust collecting electrode 70 during the air cleaning operation. The holding member 62 and the holding member 74 are made of an insulating material, and are fixed to the heat shield plate 80. In addition, a terminal 71 a of a heating wire 76 (FIG. 5) protrudes from an end surface of the grip portion 72.

The discharge electrode 60 and the collection electrode 7 of the electric precipitator 50
0 is shown in FIG. The dust collection electrode 70 has a heating element 71 such as a sheathed heater as a base, a metal tube 75, and an electric resistance wire 76 (heating wire such as a nichrome wire, hereinafter referred to as a heating wire) inserted into the metal tube 75. And an electrical insulator 77 in the form of an insulating powder such as magnesium oxide filled therein. A predetermined portion of the outer surface of the metal tube 75 is coated with an insulating layer 78 made of a fluororesin, and a catalytic layer 79 made of an oxidation catalyst typified by activated alumina, manganese dioxide or the like is further applied or welded thereon. And the like. The catalyst layer 79 is made conductive by adding a conductor such as a metal oxide or iron powder. The terminal fitting 70a is electrically connected to the conductive catalyst layer 79. The end of the metal tube 75 is sealed with a glass sealing material 81.

The catalyst layer 79 may be formed by adding a metal oxide to a hygroscopic catalyst such as zeolite (generally called zeolite) instead of the above composition. The addition amount of the metal oxide should be large so that the discharge resistance is 1 MΩ or less when the hygroscopic catalyst does not absorb moisture (in the moisture absorption state, the conductivity increases more and the discharge resistance decreases). ). Zeolite has a three-dimensional network structure having a cavity, and promotes the reaction of molecules adsorbed in the cavity. Note that activated alumina (Al ₂ O
₃ ) is an alumina fine powder having a high adsorption capacity, a small crystal grain size and a large surface area, and is suitable as a catalyst, a catalyst carrier, and an adsorbent. Manganese dioxide (MnO ₂ ) has a function as a catalyst similarly to zeolite and activated alumina.

Between the discharge wire 61 of the discharge electrode 60 and the catalyst layer 79 of the dust collecting electrode 70, a DC high voltage (± 4.
5-5 KV) is applied during the air cleaning operation. The former is positive,
A negative voltage is applied to the latter. Further, an AC voltage of 100 V is applied to the heating wire 76 from an AC power supply during self-cleaning. The discharge electrode 60 is controlled by a control circuit (not shown).
And the timing of applying each voltage to the dust collecting electrode 70 and the heating wire 76 is controlled.

Next, the operation of the air conditioner 1 with the dust collector configured as described above will be described. During air conditioning, by operating the heat exchanger 30 and the fan 40, the room air is supplied to the front grill 21 of the front panel 20 and the filter 32.
And is sucked into the casing 10 through the heat exchanger 30.
After being cooled or heated in the process of passing through, the air flows through the ventilation path 31 on the rear side from top to bottom. The air passing through the ventilation passage 31 passes around the dust collector 50. Here, if a high voltage is applied to the discharge wire 61 of the discharge electrode 60 and the catalyst layer 79 of the dust collection electrode 70, a corona discharge occurs between the electrodes 60 and 70, and the air around the discharge electrode 60 Dust such as fine particles of tobacco tar (oil smoke) and cotton dust present therein are positively charged, attracted to the dust collecting electrode 70 by Coulomb force between both electrodes, and collected by the dust collecting electrode 70. When fine particles containing an odor component are contained in the air, the odor component is adsorbed and deodorized by the catalyst layer 79 of the dust collection electrode 70. In this way, the air that has passed through the heat exchanger 30 is purified in the process of passing through the ventilation path 31 on the back side, and
2 is discharged into the room. In this way, the air sucked in from the air inlet 13 is purified in the process of passing through the ventilation passage 31 and is discharged from the air outlet 14 into the room.

Here, a heating element 71 having a metal tube 75 is used as a base of the dust collecting electrode 70, and a conductive catalyst layer is formed on the outer surface of the metal tube 75 via an insulating layer 78 made of a fluororesin. Since 79 is provided, the dielectric strength between the heating wire 76 and the catalyst layer 79 to which a high voltage is applied is the same as that between the heating wire and the metal tube when a conventional sheathed heater is used for the base of the dust collection electrode. The catalyst layer 79
To prevent the leakage current from flowing through the heating wire 76. This eliminates the need to arrange a high-voltage relay circuit between the heating wire 76 and the AC power supply, simplifies the high-voltage generation circuit, reduces the size and space of the circuit board on which the high-voltage generation circuit is mounted, and saves these circuits. Can be reduced, and the size and cost of the air conditioner 1 with an electrostatic precipitator can be reduced.

Further, in order to increase the insulation distance between the metal tube 75 and the heating wire 76, it is not necessary to increase the outer diameter of the heating element 71, such as a sheathed heater, which serves as a base. Not even. Further, the insulating layer 78 made of a fluororesin formed on the outer surface of the metal tube 75 is extremely resistant to dielectric breakdown (10 to 25 KV / mm). In addition, since a sheathed heater or the like is used as the base, heat resistance and weather resistance are excellent.

Next, the self-cleaning operation of the catalyst layer 79 will be described. At the time of self-cleaning, an AC voltage of 100 V is applied to the heating wire 76 of the heating element 71 of the dust collecting electrode 70, whereby the heating wire 76 generates heat, the metal tube 75 is heated, and the temperature of the catalyst layer 79 is increased. The attached dust is oxidatively decomposed stepwise by the oxidizing action of the catalyst, and finally the dust is turned into a colorless and odorless gas of carbon dioxide and water vapor.
Thus, dust on the catalyst layer 79 is removed.

Conventionally, when a high voltage is applied to the dust collecting electrode by the dust collecting operation, a leak current may flow from the dust collecting electrode toward the heating wire. Must be electrically insulated by a high-voltage relay circuit or the like, which makes it difficult to simultaneously perform the dust collection operation and the self-cleaning operation. It can only be performed when the clean operation is stopped after the operation time has elapsed. On the other hand, in the present embodiment, it is possible to prevent a leak current from flowing from the dust collection electrode to the heating wire, so that it is possible to perform the self-cleaning operation while performing the dust collection operation constantly or as needed. .

As described above, as the catalyst layer 79,
In the case where a metal oxide is added to a hygroscopic catalyst such as zeolite, the metal oxide is added so that the discharge resistance is 1 MΩ or less without absorbing moisture. In the air conditioner provided with the above, the catalyst layer 79 may be made of only a hygroscopic catalyst such as zeolite without adding a metal oxide.

The present invention is not limited to the above embodiment, but can be variously modified. For example, an air purifier having only an air purifying function may be one in which the above-described dust collecting electrode is applied.

[0030]

As described above, according to the present invention, a metal tube such as a sheathed heater is used as a base of a dust collecting electrode, and the outer surface of the metal tube is covered with an insulating material. Since the oxidation catalyst is provided with a catalyst layer obtained by adding a metal oxide or a conductor, the dielectric strength between the conductive catalyst layer and the heating wire in the metal tube is high, and when a high voltage is applied to the catalyst layer, It is possible to prevent a leak current from flowing from the catalyst layer toward the heating wire. As a result, the mechanical strength of the heating element serving as the dust collecting electrode is sufficient, and it is not necessary to provide a high-voltage relay circuit as in the conventional case. This simplifies the high-voltage generation circuit and reduces the circuit board on which the high-voltage generation circuit is mounted Therefore, it is possible to reduce the number of parts and the parts cost constituting these circuits. Further, the size and cost of the air purifier and the air conditioner can be reduced. Further, a catalyst layer made of an oxidation catalyst substance obtained by adding a metal oxide to a substance whose conductivity is increased by moisture absorption may be provided on the insulating material formed on the outer surface of the metal tube, and the substance absorbs moisture. Thereby, the same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an air conditioner with an electric dust collector according to an embodiment of the present invention.

FIG. 2 is a partial perspective view of the electric precipitator.

FIG. 3 is a side view of the electric dust collector.

FIG. 4 is a partial bottom view of the electric precipitator.

FIG. 5 is a sectional view of a dust collecting electrode of the electric dust collecting electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air conditioner with an electric dust collector 60 Discharge electrode 61 Discharge wire 70 Dust collecting electrode 71 Heating element (Seed heater) 75 Metal tube 76 Heating wire 77 Electric insulator 78 Insulation layer (insulation material) made of fluororesin 79 Catalyst layer

Claims (5)

[Claims] 1. A discharge electrode to which a high voltage is applied, and a dust collection electrode provided opposite to the discharge electrode and to which a voltage having a polarity opposite to the high voltage is applied, wherein: Using a heating element in which a heating wire is inserted into a metal tube and filled with an electrical insulator, the dust contained in the air is collected by using a discharging action by applying a high voltage between the two electrodes. In an electric dust collector that collects dust at an electrode, the dust collecting electrode covers an outer surface of the metal tube with an insulating material, and further has a catalyst layer obtained by adding a metal oxide or a conductor to an oxidation catalyst, An electric precipitator, wherein the voltage is applied to the catalyst layer. 2. A discharge electrode to which a high voltage is applied, and a dust collection electrode provided to face the discharge electrode and to which a voltage having a polarity opposite to the high voltage is applied, wherein: Using a heating element in which a heating wire is inserted into a metal tube and filled with an electrical insulator, the dust contained in the air is collected by using a discharging action by applying a high voltage between the two electrodes. In an electric dust collector for collecting dust on an electrode, the dust collecting electrode is formed of an oxidation catalyst material obtained by coating an outer surface of the metal tube with an insulating material and further adding a metal oxide to a hygroscopic material. An electrostatic precipitator comprising a catalyst layer, and the voltage is applied to the catalyst layer. 3. The electrostatic precipitator according to claim 1, wherein the insulating material covering the outer surface of the metal tube is a fluororesin. 4. An air conditioner comprising: a heat exchanger for air conditioning; and an electric dust collector disposed in a ventilation path of air to be heat-exchanged by the heat exchanger and collecting dust contained in the air. The electric dust collector includes a discharge electrode to which a high voltage is applied, and a dust collection electrode provided to face the discharge electrode and to which a voltage having a polarity opposite to that of the high voltage is applied. A heating element in which a heating wire is inserted into a metal tube and filled with an electrical insulator is used, and dust contained in the air is collected by using a discharging action caused by application of a high voltage between the two electrodes. An outer surface of the metal tube is coated with an insulating material, and a catalyst layer obtained by adding a metal oxide or a conductor to an oxidation catalyst is provided thereon, and the voltage is applied to the catalyst layer. An air conditioner characterized in that: 5. An air conditioner comprising: a heat exchanger for air conditioning; and an electric dust collector disposed in a ventilation path of air to be heat-exchanged by the heat exchanger and collecting dust contained in the air. The electric dust collector includes a discharge electrode to which a high voltage is applied, and a dust collection electrode provided to face the discharge electrode and to which a voltage having a polarity opposite to that of the high voltage is applied. A heating element in which a heating wire is inserted into a metal tube and filled with an electrical insulator is used, and dust contained in the air is collected by using a discharging action caused by application of a high voltage between the two electrodes. An outer surface of the metal tube is coated with an insulating material, and a catalyst layer made of an oxidation catalyst material obtained by adding a metal oxide to a hygroscopic material is further provided thereon. It is characterized by applying a voltage Air conditioner.