JP3645983B2 - Electrostatic precipitator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic precipitator.
[0002]
[Prior art]
Conventionally, there is an electrostatic precipitator that is attached to a cutting machine and collects fine particles such as mist of cutting oil generated from the machine tool by the electrostatic precipitator. That is, an inlet for introducing air (fluid) containing fine particles into the case and an outlet for extracting air from the case are formed in the upper and lower parts of the case in the electrostatic precipitator. The introduction port and the discharge port are communicated with each other by a cylindrical dust collecting electrode disposed in the case so as to extend in the vertical direction, and are led out from the discharge port. A discharge electrode is provided inside the dust collection electrode.
[0003]
Then, by applying a voltage to the dust collecting electrode and the discharge electrode, a DC electric field is generated between the two electrodes, and fine particles contained in the air flowing through the dust collecting electrode are charged by the DC electric field. Then, the fine particles receive Coulomb attractive force and move toward the inner surface of the dust collecting electrode, and are attached to the inner surface of the dust collecting electrode. As a result, fine particles are removed from the air, and air from which fine particles have been removed is led out from the outlet.
[0004]
[Problems to be solved by the invention]
However, the conventional electrostatic precipitator described above has a problem in that, when the amount of fine particles contained in the air increases, the charging efficiency of the fine particles decreases, so that the collection efficiency of the fine particles decreases.
[0005]
An object of the present invention is to improve the collection efficiency of fine particles by preventing the charging efficiency of the fine particles from being lowered.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is a dust collecting electrode for adhering fine particles contained in a fluid, a discharge electrode provided in the dust collecting electrode for charging fine particles contained in the fluid, and an upstream side of the discharge electrode. The present invention is provided with an auxiliary discharge electrode that is provided and charges the fine particles contained in the fluid before the fine particles are charged by the discharge electrode.
[0007]
The invention according to claim 2 is the invention according to claim 1, wherein a plurality of the dust collection electrode, discharge electrode and auxiliary discharge electrode are provided, and each auxiliary discharge electrode faces each dust collection electrode or each discharge electrode. The gist is that they are respectively arranged.
[0008]
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the auxiliary discharge electrode charges the fine particles in at least one of the upstream direction and the downstream direction of the fluid. It is a summary.
[0009]
Therefore, the invention described in claims 1 to 3 has the following effects.
In the first aspect of the invention, the fine particles contained in the air are charged by the auxiliary discharge electrode. When a voltage is applied to the dust collecting electrode and the discharge electrode, direct current electrolysis occurs between both electrodes, and fine particles contained in the fluid flowing through the dust collecting electrode are attached to the dust collecting electrode by the direct current electrolysis. Since the fine particles are already charged by the auxiliary discharge electrode before the fine particles are charged by the discharge electrode, the charging efficiency of the fine particles does not decrease.
[0010]
In the second aspect of the present invention, since each auxiliary discharge electrode is disposed opposite to each dust collecting electrode, the particles in the vicinity of the dust collecting electrode are easily charged.
In the invention according to claim 3, even if it is not charged on the upstream side of the auxiliary discharge electrode, it is also charged on the downstream side of the auxiliary discharge electrode.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, an inlet 3 is provided in the lower part of the case 2 in the electrostatic precipitator 1, and an outlet 4 is provided in the upper part of the case 2. A fan F is provided on the upper portion of the case 2, and air as a fluid is attracted into the case 2 through the inlet 3 by the fan F, and is led out of the case 2 through the outlet 4.
[0012]
As shown in FIGS. 1 to 3, upper and lower dust collecting portions 6 and 7 are provided in the case 2 via brackets 5 disposed at corner portions thereof. Each bracket 5 is provided with a plurality of square pipes 8 as a dust collecting electrode made of a conductor, and both upper and lower ends of each square pipe 8 are opened. Ten square pipes 8 are arranged in columns and rows (100 in total), and adjacent square pipes 8 are fixed to each other by welding.
[0013]
As shown in FIGS. 1, 2, and 4, an insulating spacer 9 is provided at the upper end of each bracket 5, and an electrode support plate 10 is fastened and fixed to the upper end of each insulating spacer 9 by a mounting screw 11. Therefore, both the electrode support plate 10 and the square pipe 8 are insulated from the case 2. A plurality of air passage holes 12 are formed in the electrode support plate 10 at a constant interval in the width direction, and a plurality of through holes 13 are formed in the vicinity of both sides of the air passage hole 12 along the longitudinal direction. Is formed. A discharge electrode 14 extending in the vertical direction is press-fitted into each through hole 13, and the discharge electrode 14 and the electrode support plate 10 are electrically connected. Each discharge electrode 14 is loosely inserted into each of the pipes 8, and a sharp discharge portion 14a is formed at the lower end thereof. The outer peripheral surface of the discharge electrode 14 is covered with an insulating material such as nylon resin except for the discharge portion 14a.
[0014]
As shown in FIG. 2, the square pipe 8 and the discharge electrode 14 are connected to a power source 15. A positive voltage of 10.5 kilovolts is applied to the square pipe 8, while a negative voltage of 10.5 kilovolts is applied to the discharge electrode 14.
[0015]
As shown in FIGS. 1, 5, and 6, an electrode support plate 17 is supported inside the upper end of the introduction port 3 via an insulating spacer 16, and the electrode support plate 17 is attached to the insulating spacer 16 by screws 18. Tightened and fixed. A plurality of air passage holes 19 are formed in the electrode support plate 17 at a constant interval in the width direction, and a plurality of attachment holes 20 are formed in the vicinity of both sides of each air passage hole 19 along the longitudinal direction. Is formed. Auxiliary discharge electrodes 21 extending in the up-down direction are respectively supported through the mounting holes 20.
[0016]
Each auxiliary discharge electrode 21 is disposed on the central axis of each discharge electrode 14, that is, on the same axis of each discharge electrode 14 along the air flow. Each auxiliary discharge electrode 21 includes a lower electrode pin 22 extending from the electrode support plate 17 toward the upstream side of the air, and an upper electrode pin 23 extending toward the downstream side. Both electrode pins 22 and 23 are disposed so that their axes coincide with each other, and the base end portions of both electrode pins 22 and 23 are integrally formed. The tip portions of the electrode pins 22 and 23 are respectively formed with sharp discharge portions 22a and 23a. The outer peripheral surfaces of the electrode pins 22 and 23 except for the discharge portions 22a and 23a are made of an insulating material such as nylon resin. Is covered. As shown in FIG. 5, the auxiliary discharge electrode 21 is connected to the power source 15, and a negative voltage of 10.5 kilovolts is applied to the auxiliary electrode 21 from the power source 15.
[0017]
Next, the operation of the electrostatic precipitator configured as described above will be described.
When the fan F is driven, air containing fine particles such as mist of cutting oil generated from the machine tool is attracted into the case 2 through the inlet 3. At this time, when a negative voltage is applied to the auxiliary discharge electrode 21, the discharge is performed from the discharge portions 22a and 23a of the upper and lower electrode pins 22 and 23 toward the upstream side and the downstream side of the air. Then, on the upstream side of the electrode support plate 17, the fine particles contained in the air are negatively charged by the discharge from the discharge portion 22 a of the lower electrode pin 22. The fine particles contained in the air that has passed through the air passage hole 19 of the electrode support plate 17 and not charged on the upstream side of the electrode support plate 17 are discharged from the discharge portion 23a of the upper electrode pin 23. Is charged by. That is, fine particles are charged on the upstream side and downstream side of the electrode support plate 17, and many fine particles are charged on the upstream side of the lower dust collecting portion 7.
[0018]
When discharged from the discharge portion 14a of the discharge electrode 14 in the lower dust collection portion 7, the fine particles that are not charged by the auxiliary discharge electrode 21 are charged. Therefore, even if the air contains many fine particles, most of the fine particles are charged before passing through the lower dust collecting portion 7. Fine particles are attracted to the inner surface of the square pipe 8 by a strong Coulomb force generated by a direct current electric field between the discharge electrode 14 and the square pipe 8 in the lower dust collecting portion 7. As a result, the fine particles adhere to the inner surface of the square pipe 8 and the air is purified.
[0019]
The purified air passes through the air passage hole 12 of the lower dust collecting portion 7 and is attracted to the upper dust collecting portion 6, and further air purification is performed at the upper dust collecting portion 6 in the same manner as the lower dust collecting portion 7. Is called. That is, a direct current electric field is generated between the discharge electrode 14 and the square pipe 8 in the upper dust collection unit 6, and the fine particles that have not been collected in the lower dust collection unit 7 due to the direct current electric field are square pipe 8 of the upper dust collection unit 6. To the inner surface of the same-angle pipe 8. Then, the air purified by both the dust collecting portions 7 and 8 is led out of the case 2 through the outlet 4. On the other hand, fine particles such as mist adhering to the square pipes 8 of the dust collecting portions 6 and 7 are combined with each other to form droplets, and the droplets fall outside the case 2 and are collected at the bottom of the inlet 3. .
[0020]
Next, effects that can be found from this embodiment will be described below.
-Since the auxiliary discharge electrode 21 is provided on the upstream side of the discharge electrode 14, most of the fine particles contained in the air attracted to the vicinity of the lower dust collecting portion 7 are negatively charged. Therefore, even if the amount of fine particles contained in the air is increased, the charging efficiency of the fine particles can be prevented from being lowered, and the collection efficiency of the fine particles can be improved.
[0021]
Since each auxiliary discharge electrode 21 is disposed so as to face each square pipe 8 or each discharge electrode 14 of the lower dust collecting section 7, the fine particles in the case 2 can be uniformly charged without unevenness. Therefore, there is no variation in the amount of fine particles adhering to each square pipe 8 in the lower dust collecting portion 7. Therefore, the collection efficiency of the fine particles can be kept high.
[0022]
Since discharge is performed from the discharge portions 22a and 23a of each auxiliary discharge electrode 21 in the upstream and downstream directions of air, even if fine particles pass through the auxiliary discharge electrode 21 without being charged, the discharge is downstream of the auxiliary discharge electrode 21. Can be reliably charged on the side. Accordingly, it is possible to further prevent the charging efficiency of the fine particles from being lowered.
[0023]
In addition, you may comprise the said embodiment as follows.
-The auxiliary discharge electrode 21 is provided only between the upper and lower dust collecting parts 6 and 7. Alternatively, auxiliary discharge electrodes 21 may be provided between the upper and lower dust collectors 6 and 7 and upstream of the lower dust collector 7.
[0024]
The auxiliary discharge electrode 21 is composed of a lower electrode pin 22 and an upper electrode pin 23 that are separate from each other.
The auxiliary discharge electrode 21 is composed of either the lower electrode pin 22 or the upper electrode pin 23 and discharges only in either the upstream direction or the downstream direction of the air.
[0025]
Next, technical ideas other than the claims that can be grasped from the embodiment will be described together with their effects.
(A) The electrostatic precipitator according to any one of claims 1 to 3, wherein the auxiliary discharge electrode has a discharge part having both ends thereof sharpened.
[0026]
(B) The discharge electrode is arranged so that its axis is along the direction of fluid flow, and the auxiliary discharge electrode is arranged so as to coincide with the discharge electrode on the same axis. The electrostatic precipitator according to any one of a). According to this configuration, the collection efficiency of the fine particles can be further improved.
[0027]
(C) The electrostatic dust collection electrode according to any one of claims 1 to 3, (a), and (b), wherein the upstream and downstream electrode pins are integrally formed. According to this structure, it can prevent that the assembly man-hour of an auxiliary discharge electrode increases.
[0028]
(D) The electrostatic dust collection electrode according to (b) or (c), wherein the upstream and downstream electrode pins are arranged so that their axes coincide with each other. According to this configuration, the auxiliary discharge electrode can be easily assembled.
[0029]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects.
According to the first aspect of the present invention, since it is possible to prevent the charging efficiency of the fine particles contained in the fluid from being lowered, the recovery efficiency of the fine particles is improved.
[0030]
According to the second aspect of the present invention, since the auxiliary discharge electrode is disposed so as to face each dust collecting electrode, the collection efficiency of the fine particles can be kept high.
According to the third aspect of the present invention, uncharged fine particles can be charged either through the auxiliary discharge electrode or downstream thereof. Therefore, it is possible to further prevent the charging efficiency of the fine particles from being lowered.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing an electrostatic precipitator embodying an embodiment.
FIG. 2 is an enlarged cross-sectional view showing an upper or lower dust collecting portion.
3 is a sectional view taken along line XX in FIG.
FIG. 4 is a plan view showing an electrode support plate in both upper and lower dust collecting portions.
FIG. 5 is a partially enlarged front sectional view showing an auxiliary discharge electrode.
FIG. 6 is a partially enlarged front perspective view showing an auxiliary discharge electrode.
[Explanation of symbols]
8 ... Square pipe (dust collecting electrode), 14 ... Discharge electrode, 21 ... Auxiliary discharge electrode.

Claims (3)

A dust collecting electrode for adhering fine particles contained in the fluid;
A discharge electrode provided in the dust collecting electrode and charging fine particles contained in the fluid;
An electrostatic precipitator provided with an auxiliary discharge electrode provided on the upstream side of the discharge electrode and charging fine particles contained in a fluid before charging the fine particles by the discharge electrode. 2. The electrostatic precipitator according to claim 1, wherein a plurality of the dust collection electrodes, discharge electrodes, and auxiliary discharge electrodes are provided, and each auxiliary discharge electrode is disposed to face each dust collection electrode or each discharge electrode. The electrostatic precipitating electrode according to claim 1 or 2, wherein the auxiliary discharge electrode discharges in at least one of an upstream direction and a downstream direction of the fluid.

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