WO2007073020A1

WO2007073020A1 - Electrostatic precipitator using induction voltage

Info

Publication number: WO2007073020A1
Application number: PCT/KR2006/001479
Authority: WO
Inventors: Jong Seung Chung
Original assignee: ROYAL INDUSTRIAL TECH CORP
Current assignee: ROYAL INDUSTRIAL TECH CORP
Priority date: 2005-12-22
Filing date: 2006-04-20
Publication date: 2007-06-28
Anticipated expiration: 2008-06-22
Also published as: KR100724556B1

Abstract

An electrostatic precipitator is disclosed. The electrostatic precipitator includes discharging electrodes connected to a high voltage to charge articles by a corona discharge and including a plurality of projecting portions; dust collecting electrodes arranged in parallel to collect the charged particles and being grounded; and induction voltage plates which are arranged parallel to the discharging electrode between the dust collecting electrodes, are not electrically connected, and generate voltages induced by the discharging electrodes.

Description

Description ELECTROSTATIC PRECIPITATOR USING INDUCTION

VOLTAGE

Technical Field

[1] The present invention relates to an electrostatic precipitator (ESP) in which dust particles are electrically charged by the corona discharge and charged dust particles are tugged to the dust collecting electrode for collecting the dust particles, where the electrostatic precipitator comprises discharging electrodes for discharging electrons for charging the dust particles and dust collecting electrodes arranged in parallel.

Background Art

[2] The electrostatic precipitator collects particles such that dust particles contained in polluted air are charged and the charged particles are collected and sticked to the dust collecting electrode by Coulomb force (i.e., electrostatic force) as shown in FlG. 1 which shows a basic principle of the typical electrostatic precipitator.

[3] In the electrostatic precipitator, a high voltage is applied to the discharging electrode to form the electric field, and the dust particles are charged by charges produced around the discharging electrode by the corona discharge which is a phenomenon that among the two electrodes the electrode having the stronger electric field has conductivity by the high voltage. The charged dust particles are tugged to the dust collecting electrode by the Coulomb force generated in direction of the dust collecting electrode in the electric field, whereby the dust particles are collected and sticked to the surface of the dust collecting electrode.

[4] The electrostatic precipitator includes a single-stage precipitator and a dual-stage precipitator. The single-stage precipitator is called a Cottrell electrostatic precipitator which integrates an ionization step and a collection steps. The Cottrell precipitator is widely used as an air cleaner means. The Cottrell precipitator operates at a high voltage between 30Kvolts and lOOKvolts and is usually installed in big industrial plants. The Cottrell precipitator has a simple structure and an excellent dust collecting performance but is difficult to suppress deionization because it repetitively applies electricity to collect the dust particles. In addition, the high voltage should be applied to the dust collecting electrode, and the dust collecting ability may be lost when discharge takes place in the dust collecting electrode. Since the dust particles can be accumulated on the dust collecting electrode up to the thickness of about 8 D to 12.7 D, the dust particles should be rapped continuously to maintain the dust collecting ability. Thus, the Cottrell precipitator has to have a sprinkler or a component for applying a mechanical impact or vibration. That is, when the dust particles are not regularly rapped, the deionization occurs to neutralize the charged dust particles, whereby the dust collecting performance is degraded and the collected dust particles are neutralized and thus reentrained.

[5] The dual-stage precipitator separately has the discharger and the dust collector. The dual-stage precipitator forms the electric field by the voltage difference between the discharging electrode for charging the dust particles and the dust collecting electrode and tugs the charged dust particles to the dust collecting electrode of the dust collector when the charged dust particles flow into the electric field. The dual-stage precipitator is usually used in an air cleaning process having a relative low dust density. The dual- stage precipitator does not undergo the deionization, but it discharges the reetrained dust particles as is and also it has a complicated structure. Disclosure of Invention

Technical Problem

[6] It is an object of the present invention to provide an electrostatic precipitator in which dust collecting electrodes are grounded and thus is not electrically connected, and induction voltage plates generates the induction voltage induced by projective discharging electrodes and are installed between the dust collecting electrodes to form the electric field and add the attractive force to the charged particles being tugged to the grounded dust collecting electrode by the Coulomb's law, whereby reentrainment and deionization are prevented, mechanical strength is increased because the conventional discharging electrodes of the wire type are substituted by the projective discharging electrodes of the saw form, the maintenance and assembly are easy, and the manufacturing cost is low.

[7] The present invention provides an electrostatic precipitator, comprising: discharging electrodes connected to a high voltage to charge articles by a corona discharge and including a plurality of projecting portions; dust collecting electrodes arranged in parallel to collect the charged particles and being grounded; and induction voltage plates which are arranged parallel to the discharging electrode between the dust collecting electrodes, are not electrically connected, and generate voltages induced by the discharging electrodes.

[8] Each of the discharging electrodes includes a coupling hole formed in an upper or lower portion or both, and the electrostatic precipitator further comprises a power supplying support coupled to the coupling hole to fix and electrically connect the discharging electrodes.

Description of Drawings

[9] The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail preferred em- bodiments thereof with reference to the attached drawings in which:

[10] FlG. 1 is a diagram illustrating a basic principle of a conventional electrostatic precipitator;

[11] FlGs. 2 and 3 are diagrams illustrating a basic principle of an electrostatic precipitator using an induction voltage according to the present invention;

[12] FlG. 4 is a cross-sectional view illustrating projective discharging electrode of the electrostatic precipitator according to the present invention;

[13] FlG. 5 is a diagram illustrating installation of the projective discharging electrodes of the electrostatic precipitator according to the present invention; and

[14] FlG. 6 is a perspective view illustrating the electrostatic precipitator according to the present invention.

Best Mode

[15] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thickness of layers and regions are exaggerated for clarity. Like numbers refer to like elements throughout the specification.

[16] FlGs. 2 and 3 are diagrams illustrating a basic principle of an electrostatic precipitator using an induction voltage according to the present invention. A projective discharging electrode 10 which projects out of its surface is connected to a power source to be supplied with charges from a high DC voltage of more than 1 lKvolts, and the charges are charged at projecting portions of the projective discharging electrode and then discharged by the corona discharge phenomenon to form a charging region A2. Particles 1 of dust contained the polluted air coming from the external portion are in an electrically neutral state, and when the particles 1 of the electrical neutral state enter the charging region A2 the particles 1 are changed to charged particles 2 of the negative state by the impact or absorption with anionic gas molecules.

[17] The principle that the particles are charged is as follows. The projective discharging electrode 10 forms the strong electric field by the corona discharge, and the strong electric field accelerates free electrons existing in air. The accelerated free electrons move fast to impact different gas molecules. The gas molecules impacted on the accelerated free electrons become cationic while emitting the free electron one more. The cationic gas molecules move to impact gas molecules surrounding the discharging electrode 10 or the projective discharging electrode 10, generating new free electrons. The new free electrons move forward dust collecting electrode 30 and 30-1 which are grounded along the electric field, and the moving speed of the free electron is suddenly decreased since the electric field is weak when they escape from the corona region Al. That is, the free electrons impact the gas molecules at a velocity which cannot ionize the gas molecules and are absorbed to a surface of the gas molecules to form anionic gas molecules. The anionic gas molecules impact or are absorbed to the particles 2 in the charging region A2 to charge the particles 2.

[18] An induction voltage plate 20 is arranged apart from and parallel to the projective discharging electrode 10 and is charged by the projective discharging electrode 10 to generate the negative induction voltage, and the both dust collecting electrodes 30 and 30-1 are charged by electrostatic induction and electrostatic discharge.

[19] Thus, the electric field is formed between the induction voltage plate 20 and the respective dust collecting electrodes 30 and 30-1. The charged particles 2-1 entering the electric field are tugged and sticked to the dust collecting electrodes 30 and 30-1 because the attractive force is generated from the dust collecting electrodes 30 and 30-1 and the repulsive force is generated from the induction voltage plate 20. The particles 3 sticked to the dust collecting electrodes 30 and 30-1 lose the charges and become neutral. The attractive force and the repulsive force are generated by the Coulomb's law, and description on those is omitted.

[20] FlG. 4 is a cross-sectional view illustrating the projective discharging electrode of the electrostatic precipitator according to the present invention. The projective discharging electrode 10 has a plurality of projecting portions 110 which are arranged in a longitudinal direction in a saw form at a predetermined height. The projecting portions 110 help the corona discharge to occur at a low voltage and are formed on both sides of the projective discharging electrode 10. Couple holes 120 are formed on an upper or lower portion or both of the projective discharging electrode 10 and used to be coupled with a power supplying support which is supplied with the electric power and fixes the projecting discharge electrode 10. The shape of the projective discharging electrode is not limited to that of FlG. 4, and it can be anyone which has a plate in which a plurality of projecting portions 110 are formed in a longitudinal direction.

[21] FlG. 5 is a diagram illustrating installation of the projective discharging electrodes of the electrostatic precipitator according to the present invention. A plurality of projective discharging electrodes 10 are fixed by the power supplying support 40, and the power supplying support 40 is connected to the power supplier to supply the charges of the high voltage to the projective discharging electrodes 10. The power supplying support 40 is made of a metal having a high conductivity such as copper and stably supports a plurality of projective discharging electrodes 10.

[22] FlG. 6 is a perspective view illustrating the electrostatic precipitator according to the present invention. [23] As shown in FIG. 6, a plurality of projective discharging electrodes 10 parallel- coupled to the power supplying support 40 coupled to an external high voltage supplying means 50 are arranged in a front portion of a housing 60 including an air inlet 610 from which polluted air comes and an air outlet 620 through which the clean air is exhausted, and the induction voltage plates 20 to which the high voltage is induced by the projective discharging electrodes 10 are arranged between the projective discharging electrodes 10 and the air outlet 620. The induction voltage plates are located between the dust collecting electrodes 30 without electrical connection with the dust collecting electrodes 20. That is, the dust collecting electrodes 30 and the induction voltage plates are alternately arranged between the projective discharging electrodes 10 and the air outlet 620. The polluted air flows into the housing 60 via the air inlet 610, and the polluted particles contained in the polluted air are charged while passing through the projective discharging electrodes 10 and then flow into the electric field formed between the dust collecting electrodes 30 and the induction voltage plates 20, and the charged particles are tugged to the dust collecting electrodes 30 by the Coulomb's law. As a result, the polluted air is cleaned and is exhausted through the air outlet 620. Here, the polluted particles are neutralized at the moment when they are sticked to the dust collecting electrodes 30.

[24] Even though not shown, a means for causing the air flow such as a fan is arranged in an internal or external portion of a front or rear portion of the housing 60, and a rapping means for rapping the polluted particles sticked to the dust collecting electrodes 30 is arranged. A pre-processing means for mechanically filtering the relatively big particles may be arranged.

[25] As described above, in the electrostatic precipitator using the induction voltage according to the present invention, the dust collecting electrodes are grounded instead of applying the high voltage and the induction voltage plates for generating the high voltage induced by the projective discharging electrodes are arranged. Thus, compared to the conventional dual-stage electrostatic precipitator, the electrostatic precipitator of the present invention cleans the polluted air with a relatively high dust density, preventing the reentrainment. In addition, compared to the single-stage electrostatic precipitator, the difficulty to apply the high voltage to the dust collecting electrode and the deionization problem can be resolved.

[26] Besides, since the mechanical strength of the discharging electrode is increased and there is no electrical connection between the induction voltage plates and the dust collecting electrodes, there are advantages in that the structure is simple, the maintenance and assembly are easy, and the manufacturing cost is low.

Claims

[1] An electrostatic precipitator, comprising: discharging electrodes connected to a high voltage to charge articles by a corona discharge and including a plurality of projecting portions; dust collecting electrodes arranged in parallel to collect the charged particles and being grounded; and induction voltage plates which are arranged parallel to the discharging electrode between the dust collecting electrodes, are not electrically connected, and generate voltages induced by the discharging electrodes.

[2] The electrostatic precipitator of claim 1, wherein each of the discharging electrodes includes a coupling hole formed in an upper or lower portion or both, and the electrostatic precipitator further comprises a power supplying support coupled to the coupling hole to fix and electrically connect the discharging electrodes.