JP2015223570A - Electric dust collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric dust collector which uses the ground surface on which the electric dust collector is arranged as a reference, measures the potential of an outline relative to the reference, and stops supply of high voltage to a dust collection unit when the measured voltage has become equal to hazardous voltage, even in a situation in which a ground line is not certainly connected.SOLUTION: An electric dust collector comprises: a discharge electrode 1 which applies high voltage; and a counter electrode 2 to be grounded, where a surface potential gauge 7 measures a potential difference between an outline 6 and a reference potential pole 8 which is to be ground potential of itself, and a controller 5 stops a high voltage power source 4 when the measured potential difference exceeds a predetermined threshold. Thus, even when connection of a ground line is incomplete, a danger of an electric shock can be eliminated by monitoring the potential difference between reference potential close to ground potential in the surroundings and the outline 6, and turning the high voltage power source off when there is a danger of an electric shock.

Description

  The present invention relates to an electric dust collector that collects atmospheric dust, indoor dust, dust and the like in air conditioning and industrial fields.

  Conventionally, as a configuration of a dust collection unit of an electric dust collector that collects particles, a discharge electrode and a counter electrode are arranged in parallel to a direction in which particles flow.

  When a high voltage is applied between the discharge electrode and the counter electrode, a corona discharge current (hereinafter referred to as discharge current) flows between the electrodes.

  When floating particles pass through a region where the discharge current flows, the floating particles collide with ions moving along the discharge current flow, and the floating particles are charged.

  Charged suspended particles are attracted and collected by the counter electrode by the force of the electric field generated between the discharge electrode and the counter electrode.

  Since the dust collector handles high pressures, it is necessary to pay sufficient attention to electric shocks. To protect against electric shock, the dust collector itself is covered with an insulator, and the sheet metal is covered with a sheet metal. There is a way to do it.

  Since a small and light dust collecting portion does not require much strength for fixing the dust collecting portion, an insulating material is often used for both the fixing portion and the covering portion.

  However, for heavy dust collection parts, a strong metal structure is often required to support the weight, so the metal plate and counter electrode that are covered in the final assembled state are made of metal. Most of the structures are electrically connected via fixed objects made of metal.

  In steady use, the discharge electrode and the counter electrode may be short-circuited due to conductive foreign matter. However, if the covered part is made of sheet metal and is electrically connected to the counter electrode, the potential of the discharge electrode remains as is Will appear.

  Therefore, it is always necessary to connect the outer shell of the device to the ground line from the viewpoint of preventing electric shock.

  As a conventional method for reliably grounding the casing and the counter electrode, there is an electrostatic precipitator as shown in FIG.

  In the electrostatic precipitator of FIG. 4, the grounding point and the grounding terminal 102 of the high-voltage power supply 101 are connected by the grounding bus 103, the grounding terminal 102 and the housing 104 are connected by the grounding wire 105, and the electrostatic precipitator is mounted. The existing frame support 106 is also connected to the housing 104 through a ground wire 107.

  Furthermore, the copper wire 108 stretched around the casing 104 while being electrically connected to the casing of the dust collecting portion at a plurality of locations is connected to the ground terminal 102. As a result, each dust collecting electrode and the entire casing are reliably maintained at the ground potential. (See Patent Document 1)

Japanese Patent Laid-Open No. 10-337497

  In such a conventional electrostatic precipitator, construction such as embedding the tip of the ground wire in the ground is performed. However, depending on the usage conditions, etc., there is a risk that the grounding wire may be disconnected, or the grounding resistance may be reduced due to changes in the underground conditions. When the grounding resistance is reduced, a high voltage appears on the outer surface of the electric dust collector main body, and there is a risk of electric shock if a person touches the electric dust collector in this state.

  The present invention solves such a problem, and even in a situation where the ground wire is not securely connected, the ground on which the electrostatic precipitator is placed is used as a reference, and the potential of the outer shell with respect to the reference When the measured voltage becomes dangerous voltage, supply of high voltage to the dust collector is stopped.

  Accordingly, it is possible to provide an electrostatic precipitator that does not pose a risk of electric shock even when the connection of the ground wire is incomplete.

The present invention
A dust collection part that arranges the discharge electrode and the counter electrode facing each other and collects dust by charging suspended particles in the air; a high-voltage power source that supplies high pressure to the discharge electrode;
High voltage power supply control means for turning on and off the high voltage power supply;
An outer shell covering the dust collecting portion and electrically connected to the counter electrode;
A voltage measuring means with a unique reference potential electrode;
The voltage measuring means measures a voltage between the reference potential electrode and the outer shell,
The high-voltage power supply control means turns off the high-voltage power supply when the measured value of the voltage measurement means detects a predetermined threshold value or more.

  With the above configuration, even when the grounding resistance of the electrostatic precipitator body decreases, the potential of the electric shock can be reduced by measuring the electric potential of the electrostatic precipitator device with reference to the ground where the electrostatic precipitator is installed. If there is a risk of electric shock when the presence or absence is determined, an electric dust collector that does not cause electric shock can be provided by turning off the output of the high-voltage power supply.

Schematic diagram showing the configuration of the first embodiment of the present invention Schematic diagram showing the configuration of the second embodiment of the present invention Schematic diagram showing the configuration of Embodiment 3 of the present invention Schematic showing the connection of the ground wire of a conventional electrostatic precipitator

  An electrostatic precipitator according to an embodiment of the present invention includes a dust collector that disposes a discharge electrode and a counter electrode so as to face each other and collects dust by charging suspended particles in the air, and a high pressure that supplies high pressure to the discharge electrode. A power supply, a high-voltage power supply control means for turning on / off the high-voltage power supply, a shell that covers the dust collecting part and is electrically connected to the counter electrode, and a voltage measuring means having a unique reference potential electrode The voltage measuring means measures the voltage between the reference potential electrode and the outer shell, and when the measured value of the voltage measuring means detects a predetermined threshold value or more, the high voltage power supply control means turns on the high voltage power supply. It is characterized by being turned off.

With the above configuration, by measuring the potential difference between the ground where the electrostatic precipitator is placed and the sheet metal outer shell, determine the risk of electric shock, and turn off the output of the high-voltage power supply if there is a risk of electric shock. Can prevent electric shock.

  Further, the voltage measuring means may be a non-contact type surface potential meter. With this configuration, a high-breakdown-voltage measurement circuit that is necessary for a contact-type measurement circuit can be eliminated, and the measurement circuit can be configured with a safe low-voltage circuit.

The voltage measuring means may be installed inside the outer shell. With this configuration, even when an electrostatic precipitator is installed outdoors, the measurement unit is not affected by wind and rain, and it can also prevent contamination, so it can accurately measure the external potential of the device over a long period of time. Can do.
Further, the voltage measuring means may insert a resistor between the outer shell and the reference potential electrode, and measure the voltage across the resistor. With this configuration, it is possible to simply and inexpensively configure a circuit for measuring the potential of the outer shell of the apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 shows the configuration of an electrostatic precipitator according to the first embodiment of the present invention.

  As shown in FIG. 1, the electrostatic precipitator of the present embodiment has a dust collector 3 composed of a discharge electrode 1 and a counter electrode 2, and an outer shell 6 that covers the dust collector 3. The outer shell 6 is made of metal, and is preferably made of sheet metal so as to substantially cover the inside. Furthermore, the electrostatic precipitator of the present embodiment includes a high voltage power source 4, a controller 5, and a surface potential meter 7. A high voltage power supply 4 supplies a high voltage to the discharge electrode 1. The controller 5 is a high-voltage power supply control unit, and controls ON / OFF of the high-voltage power supply 4. The counter electrode 2 is fixed by a metal base 11 that supports the outer shell 6 and a metal rod 10, and is electrically connected to the outer shell 6. The surface potentiometer 7 is a voltage measuring means, which fixes a reference potential electrode 8 on the ground serving as a reference potential and measures a potential difference between the reference potential and the outer shell 6. The reference potential electrode 8 is installed separately from the grounding of the electric dust collector body. That is, the surface potential meter 7 apparently has a different reference potential (ground potential) from the main body of the electric dust collector.

  Next, the operation of the electric dust collector of this embodiment will be described.

  The electric dust collector of the present embodiment takes in air containing dust and dust (hereinafter, suspended particles) by operating a blower (not shown). The incorporated suspended particles are charged by the discharge from the discharge electrode 1 to which a high voltage is applied. The charged floating particles are attracted to and attached to the counter electrode 2 having the opposite potential, and are removed. Then, clean air from which suspended particles are removed is discharged from the electrostatic precipitator.

  Here, in normal use of electrostatic dust collection, when the discharge electrode 1 and the counter electrode 2 come into contact with the conductive foreign matter, or the discharge electrode 1 or the counter electrode 2 is deformed by vibration or impact, the discharge electrode 1 And the counter electrode 2 may be extremely reduced in insulation resistance.

  At this time, since the outer shell 6 and the counter electrode 2 are electrically connected in structure, the voltage of the counter electrode 2 appears as it is in the outer shell 6. When the outer shell 6 is securely grounded by the ground wire, even if the voltage of the counter electrode 2 appears on the outer shell 6 as it is, current flows through the ground wire, so there is no risk of electric shock even if a person touches the outer shell 6.

  However, when the connection of the grounding wire is incomplete and the grounding resistance is lowered, a high voltage appears in the outer shell 6 and it becomes a very dangerous state.

Here, the most characteristic part according to the present embodiment will be described. That is, in order to avoid the dangerous state as described above, the electric dust collector of the present embodiment performs the following operation.

  In the electrostatic precipitator of the present embodiment, the surface potential meter 7 measures the potential of the outer shell 6, that is, the potential difference between the reference potential of the surface potential meter 7 and the outer shell 6.

  Since the surface electrometer 7 is a sensor that can be measured in a non-contact manner and can measure a voltage without directly contacting a high voltage, a high voltage circuit can be eliminated and the measurement circuit can be configured safely.

  The output of the surface electrometer 7, that is, the measured potential difference is input to the controller 5. The controller 5 compares the output of the surface electrometer 7 with a preset threshold value. Here, the threshold value set in advance is set to a voltage with no risk of electric shock. For example, this threshold value may be set to DC 60 V defined by IEC 60950-1.

  When the measured potential of the outer shell 6 becomes equal to or higher than the threshold value, the controller 5 turns off the output of the high voltage power source 4.

  As described above, since no dangerous voltage that can cause an electric shock appears in the outer shell 6, a safe electric dust collector can be provided even when grounding is not reliable.

  In the present embodiment, the single-stage electrostatic precipitator that charges and collects suspended particles by the dust collector 3 has been described. However, the two-stage electrostatic precipitator provided with a separate charging section. It can also be applied.

  The shape of the discharge electrode and the counter electrode may be any form such as a parallel plate electrode. In particular, the discharge electrode may have any form such as a discharge line or a thorn electrode.

Further, although the outer shell 6 has been described as being made of metal, a part thereof may be made of resin or another insulator.
(Embodiment 2)
The electrostatic precipitator according to the second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A characteristic part of the electrostatic precipitator according to the present embodiment is that the surface potential meter 7 is arranged inside the outer shell 6 as shown in FIG. 3 with respect to the surface potential meter 7 of the first embodiment. Yes.

  With such a configuration, even when the electrostatic precipitator is installed outdoors, the surface electrometer 7 can avoid the influence of wind and rain, and can continuously and stably measure the potential of the outer shell 6.

In addition, when arrange | positioning the surface electrometer 7 inside the outer shell 6, in order to prevent the contamination of the measurement part of the surface electrometer 7, it is good to arrange | position from the air path of an electrostatic precipitator.
(Embodiment 3)
The electrostatic precipitator according to the third embodiment of the present invention will be described with reference to FIG. The same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  A characteristic part of the electrostatic precipitator according to this embodiment is that the surface potential meter 7 according to the first and second embodiments is between the outer shell 6 and the reference potential electrode 8 as shown in FIG. A resistor 9 is provided, and the voltage measuring instrument 7b measures the potential difference between both ends of the resistor 9.

  The controller 5 determines that there is a risk of electric shock when the potential difference measured by the voltage measuring instrument 7b exceeds a preset threshold value, and turns off the output of the high-voltage power supply 4. The threshold value may be set to DC 60 V as in the first embodiment.

  As for the resistance value of the resistor 9, if the resistance value is too large, no current flows through the resistor 9, and the influence of the current flowing to the circuit for measuring the voltage cannot be ignored. On the other hand, if the resistance value is too low, the current consumption during steady operation increases and the loss of the high-voltage circuit increases. Accordingly, the resistance value of the resistor 9 is preferably set to 100 kΩ to 1 MΩ in consideration of the actual human resistance value.

  The present invention can be applied to household and industrial electric dust collectors whose outer shells are made of sheet metal.

DESCRIPTION OF SYMBOLS 1 Discharge electrode 2 Counter electrode 3 Dust collection part 4 High voltage power supply 5 Controller 6 Outer surface 7 Surface potential meter 7b Voltage measuring device 8 Reference potential electrode 9 Resistance 10 Metal rod 11 Metal base

Claims (4)

A dust collection part that arranges the discharge electrode and the counter electrode facing each other and collects dust by charging suspended particles in the air; a high-voltage power source that supplies high pressure to the discharge electrode;
High voltage power supply control means for turning on and off the high voltage power supply;
An outer shell covering the dust collecting portion and electrically connected to the counter electrode;
A voltage measuring means with a unique reference potential electrode;
The voltage measuring means measures a voltage between the reference potential electrode and the outer shell,
The electrostatic precipitator according to claim 1, wherein when the measured value of the voltage measuring means detects a predetermined threshold value or more, the high voltage power supply control means turns off the high voltage power supply. 2. The electrostatic precipitator according to claim 1, wherein the voltage measuring means is a non-contact type surface potential meter. 3. The electrostatic precipitator according to claim 1, wherein the voltage measuring means is installed inside the outer shell. 2. The electrostatic precipitator according to claim 1, wherein the voltage measuring means inserts a resistor between the outer shell and the reference potential electrode, and measures the voltage across the resistor.

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