JPS6279859A - Corona blower and electrostatic precipitator utilizing said blower - Google Patents

Abstract

PURPOSE:To remarkably improve blasting capacity and to decrease the amt. of ozone formation with a corona blower or electrostatic precipitator utilizing the corona blower by heating a corona discharge electrode. CONSTITUTION:The corona discharge electrode part 4 of the device for blasting gas by ion wind and collecting the suspended particles in the gas by preliminarily charging the same is formed of a thin T-shaped heat-resistant insulator 11 having a projection 10 projecting toward the down stream and two upper and lower L-shaped foil or thin film-like electrical conductors 12, 13 embedded therein as well as a fine heating wire 16 connected at top ends 14, 15 to the inside of the projection 10. The corona current for the voltage to be impressed between the corona discharge electrode and counter electrode is considerably increased and the velocity of the ion wind increases as well when the corona discharge electrode is heated. The amt. of the ozone to be formed with the corona discharge is considerably decreased as well.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a device for blowing gas using ion wind, and furthermore, this invention is applicable to blowing gas and precharging particles suspended in the gas. This is a device for collecting fine particles by providing a dust collection section upstream and downstream.

[Conventional technology]

Conventional devices of this type have a corona discharge electrode on the upstream side of a duct through which gas passes through the corona blower, and a porous counter electrode such as a wire mesh on the downstream side, which are insulated from each other. A proposed method is to apply a high voltage between two electrodes to generate a corona discharge from the corona discharge electrode toward the counter electrode, and use the resulting ionic wind as a motive force to blow the gas in the duct from upstream to downstream. has been done.

In addition, a dust collection unit such as an electrostatic precipitator consisting of a group of positive and negative parallel plate electrodes is installed downstream of such a corona type blower.
It has been proposed to configure a dust collector by utilizing the corona blower for blowing gas and precharging particles suspended in the gas.

[Problem that the invention seeks to solve]

The above-mentioned type of corona type blower has an extremely small motive force, and therefore, the blowing pressure and air volume of the blower are extremely low, making it impractical. Particularly when attempting to collect dust by installing a dust collecting section on the downstream side, the pressure drop causes a significant decrease in the amount of air blown, which is a major practical obstacle. In addition, in this type of device, the amount of air blown is generally proportional to the square root of the corona current.

If the applied voltage is increased and the corona current is increased in order to improve the amount of jelly delivered, the amount of ozone produced by the corona will greatly increase, resulting in bad odors, health problems, etc. Moreover, such an increase in corona current itself has a limit due to the generation of sparks.

[Means to solve the problem]

The present invention solves all of the above-mentioned problems by heating the corona discharge electrode in a corona blower or a dust collector using a corona blower, which is known per se.

That is, in the present invention, a corona discharge electrode is disposed on the upstream side of a box through which gas passes, and a counter electrode that allows free flow of gas is disposed on the downstream side so as to be insulated from each other.

A high-voltage power supply is provided to apply a voltage between both electrodes to generate corona discharge from the corona discharge electrode toward the counter electrode, and the ionic wind caused by the resulting corona discharge causes the discharge from the corona discharge electrode side to the counter electrode side. In a corona type blower that blows air toward a person, the main feature is that the corona discharge electrode is heated by an appropriate method. Another feature is that the corona discharge electrode heating type ion blower is combined with a dust collecting section and used for blowing air or for precharging particles.

In this case, the corona discharge electrode may be a thin wire electrode, a strip-shaped electrode, a needle-shaped electrode with the tip facing the counter electrode, a knife-edge electrode with the blade facing the counter electrode, or the like.

Any suitable material may be used, but in all cases it is necessary to generate corona discharge from the corona discharge electrode toward the counter electrode to generate an ion wind.

For this reason, it is necessary to electrically connect a thin wire electrode or a strip electrode to a grounding body to prevent the generation of an ion wind in the opposite direction due to corona discharge from the former toward the latter. Alternatively, the distance between the electrode and the upstream grounding body is sufficiently large.

Corona discharge must be generated from the corona discharge electrode only toward the counter electrode.

Also, as a method of heating the corona discharge electrode.

Is there a suitable heating element nearby? Although it may be possible to provide a corona discharge arc and heat it indirectly, it is generally cheaper and more efficient to heat the corona discharge arc directly by energizing it itself. In this case, it is preferable to use a corona discharge electrode in the form of a thin wire or strip, and apply a voltage between the terminals to supply the heating current.

In any case, when heating the corona discharge electrode directly or indirectly, only the tip that produces the corona discharge should be exposed toward the opposite electrode, and the other parts of the corona discharge electrode and the entire heating element should be exposed as appropriate. It is preferable to use a material that is heat resistant and thermally insulating, such as glass, ceramic, or a heat-resistant plastic (e.g., Kapton).1 This can greatly reduce heating energy, and the heated part Another advantage is that it can completely prevent fires from coming into contact with flammable floating substances.

In addition, any suitable dust collection unit can be used as the dust collection unit disposed downstream of the corona blower, but
Particles are pre-charged in the corona blower by the electric field created between the parallel electrodes by installing a large number of parallel electrodes in parallel to the gas flow, insulating them from each other, and applying a voltage between them. A parallel capacitor-type dust collecting section that collects the electricity on the parallel electrodes 4 is particularly suitable in terms of low pressure loss and high fruit thinning efficiency. It can also be replaced with an electrode.

In addition, as such a parallel capacitor type catching part, the present inventor has developed another invention "Electrostatic Precipitator" (Japanese Patent Application No. 53-145).
No. 34, Japanese Patent Application No. 17413-1983, and Japanese Patent Application No. 1983-17413
No. 61426), the present inventors have proposed a method in which conductive layers of positive and negative polarity are formed on both sides of a strip-shaped insulating film and then wound into a spiral shape, or the present inventor has proposed another invention "Electrical "Dust Collector" (Patent Application No. 1983-61472)
As proposed in 2003, conductive electrode plates and insulating spacers that allow gas to pass through are arranged alternately, and a high voltage is applied between adjacent electrode plates, or the inventor proposed Another invention “Electrostatic precipitator” (patent application 1982)
As proposed in Japanese Patent Application No. 87319 and Japanese Patent Application No. 53-91560, a conductive layer is provided so that the conductive layer is exposed only at the center of one side of the above-mentioned insulating strip film, and non-conductive portions are provided on both sides of the conductive layer. A voltage is applied between the conductive layers of adjacent electrode elements by stacking or spirally winding the conductive layers so that the conductive layers do not face each other through spacers through which gas passes. It is particularly preferable to use an electric current, since the electrode gap can be made smaller, thereby increasing the dust collection efficiency and reducing the size and weight.

[For production]

By heating the corona discharge electrode, the corona current T for the same value of voltage V applied between it and the opposing electrode increases significantly, and the speed of the ion wind, which is proportional to the square root of the current, also increases significantly. This dramatically improves the blowing capacity of the corona blower. Moreover, the amount of ozone produced with corona discharge is also significantly reduced, and the harmful effects of ozone can be completely prevented.

〔Example〕

Features of the present invention will be explained with reference to all embodiments and drawings. Fig. 1 is a longitudinal sectional view showing an example of a corona type blower according to the invention, and Fig. 2 is a perspective view of the corona discharge electrode portion thereof. In these figures.

1 is a duct through which gas flows, 2 is a gas inlet at its upstream end, and 3 is a gas outlet at its downstream end. 1 is a corona discharge electrode provided on the upstream side of the duct, and 5 is supported by a collar-shaped insulator 6 on the downstream side of the electrode 7 to block the gas flow.
An ion catcher 7 for removing leaked ions is provided downstream of the counter electrode in the form of a wire mesh, which is insulated at the mouth and allows the gas to pass freely, and at the same time removes suspended particles in the gas. Reference numerals 8 and 9 denote protective wire meshes that are provided near the gas port 2 and gas outlet 3 in the duct so as to block the gas flow and allow free flow of gas. The corona discharge electrode part 4 is a thin T-shaped current-carrying conductor 12 having a protrusion 10 projecting downstream. +3. and 12.13 protrusion I
Heat generating thin wire 1 connected to tip 14.15 located inside O
Consisting of 6, 16 is bent as shown in the figure and its pointed end 1
Only portion 7 is exposed from the downstream end edge 18 of the insulator protrusion IO and faces the counter electrode 5 to form a corona generation portion,
The parts of the heating element 16 other than 17 are embedded inside 10. The T-shaped heat-resistant insulator 11 may be made of glass or ceramics, but in one example, it is made of two plastic films (for example, Kapton) that are heat-sealable at high temperatures.
20, 12, 13, and 16 are inserted between them, and 19.20 is bonded at high temperature. Terminals 21 at the upper and lower ends of the L-shaped current-carrying conductor +2°13. Z2 is the conductor part, 24? It is connected to a DC or AC heating power source 5 with one end grounded through the thin wire heating element 16, thereby heating the thin wire heating element 16 and keeping the corona generating portion 17 at the tip thereof at a required temperature. Furthermore, conductive wires 26, 27. High voltage is applied from a high-voltage power source 4 through the insulating insulator tube blades.

As a result, a strong corona discharge occurs from the heated grounded corona generation part 17 toward the counter electrode 5 at a high potential, a large ionic current flows, a strong ionic wind is generated, and the evacuation force causes the gas population 2 to increase. Gas is sucked, flows inside the duct 1 in the direction of the arrow, and is discharged to the outside from the gas outlet 3. In this case, the high-voltage power supply 4 may be a DC power supply or an AC power supply, but when using a DC high-voltage power supply in which 17 is positive and 5 is negative, the amount of ozone generated at 17 can be suppressed to the lowest level. The ion catcher 7 has two adjacent, mutually insulated ion catchers installed in the duct parallel to the gas flow.
Parallel plate electrode groups 3+, 32. ...and 31',
Consisting of 32', 31'.

32', . . . are grounded via the common conductor 33, and 3
1,32゜-... is a common conductor, insulating tube 1' (
5 (one end is grounded and the other end is connected to the high voltage power supply through 5).

Thus, adjacent electrodes 31-31', 31'-32,
A high voltage is applied between 32-32', =...
All of the ions that have passed through the wire-mesh counter electrode 5 are collected and removed on the electrode by the electric field between the two electrodes, thereby preventing the ions from being released to the outside from the gas outlet 3 and causing various electrostatic disturbances.

In this case, suspended particles in the gas are charged by the impact of the ion stream flowing from the corona generation part 17 toward the counter electrode 5, pass through 5 and enter the ion catcher 7, and are caused by the electric field between the electrodes. It is collected on the electrode by Coulomb force.

In this case, AC power sound may be used for high voltage power supply %, but
It is preferable to use a DC power source because it can collect the above-mentioned floating particles in addition to ions with extremely high efficiency.

Next, the third drop shows a horizontal sectional view of an example of a two-stage electrostatic precipitator using the corona type blower according to the present invention for blowing air and charging particles suspended in gas, and FIG. 4 shows a vertical sectional view thereof. , 5th
The figure is a perspective view of the corona discharge electrode section 4', and FIG. 6 is a partial perspective view showing a more detailed structure of the corona generating section 17. The features and functions of the elements numbered 1 through 35 in the figure are the same as those of the elements numbered the same in FIG. 37 is a dust collecting section having the same structure as the ion catcher 7 in FIG.・
...A high DC voltage is applied between the electrodes to form a strong DC electric field between the electrodes.

However, in this case, the electrode group 31' of the dust collecting section 37 is grounded.

32', . . . serve as opposing electrodes to the corona discharge electrode section 4 to which a high positive voltage is applied with respect to the ground by the DC high voltage power supply 39. In this example, the corona discharge electrode section 4' is made of two thin tape-shaped films 40 and 41 of heat-resistant plastic (such as Kapton) that is heat-sealable at high temperatures, as shown in FIG. The strip-shaped metal tape 42 is sandwiched in the shape of a sandwich, and as shown in the figure, one peripheral edge 43 of the metal tape 42 is aligned with the peripheral edge 45 of the tape-shaped heat-resistant plastic membrane 40, 4+, so that the membrane 40 .41, but is exposed to the outside from between the peripheral edges 45, forming a sharp knife-edge corona generation part 17, and another peripheral edge 46 of the metal tape 42 is formed between the membranes 40 and 41. It should be positioned sufficiently inwardly than the other periphery 47°48.

All parts of the metal tape 42 except for the periphery 43 are completely integrated into the plastic membrane 40.41 by pressing and heat-sealing the membrane 40.41'i together at high temperatures, and 42 Another peripheral edge 46 of is not exposed to the outside. A long tape-shaped discharge electrode portion 4' configured in this way
As shown in FIG. 5, the knife-edge corona generating portion 17
Insulating holders 49 and 49' made of upper and lower insulators so that they face downstream.

Wrap it around in a zigzag pattern and insulate and fix it at both ends so that the surfaces of adjacent discharge electrode parts 1' are equally spaced and parallel to each other and parallel to the gas flow, as shown in Figure 3. It is arranged on the cross section of the upstream part of the duct 1. Both ends 50 of the metal tape 42 of this tape-shaped corona discharge electrode portion 4',
' 51 is the conductor 52, 53 and the insulated pipe 54? is connected to the secondary side of the isolation transformer 55 through the
, 56, the AC heating current is fully supplied and heated. Moreover, a positive DC high voltage is applied to the earth from the DC high voltage power supply 39 via the conductor 57. Upstream periphery 3 of grounding electrode group 3+', 32',...
1", 32', ... These positive ions and five charged fine particles enter between the electrode groups of the dust collecting section 37.

It is collected on the negative electrode groups 3)', 32', . . . . The purified gas from which positive ions can be removed is discharged from the gas outlet 3 to the outside. Since the tape-shaped corona discharge electrode 4' of this example is a long tape, it is extremely easy to stretch it, and the metal tape 42 is completely heat-resistant except for the peripheral exposed portion 17 where the corona is generated. The heat-resistant plastic that can be fused is embedded in the membrane, so it is sufficiently thermally insulated against the gas flow, allowing for sufficient heating with a small amount of power consumption, and also has an extremely high level of safety. has.

FIG. 7 shows a horizontal sectional view of another example of an electrostatic precipitator using a corona type blower according to the present invention for blowing air and charging particles suspended in a gas. In this example, a tape-shaped corona discharge electrode portion 4 shown in FIGS. 3 to 6 is used as a corona discharge electrode portion.
' is used, and a conductor 52. is connected to it from the heating power source 5.
53 and the insulator tube 54, the corona generating portion 1 is applied to the metal tape 42 and ′.
7 are heated, but these are grounded via a conducting wire 53. The names and functions of the elements numbered l through 51 in the figures are the same as those of the elements numbered the same in the figures from FIGS. 1 to 6. In particular, in this example, the counter electrode 5' consists of a group of metal rods perpendicular to the plane of the paper in order to reduce ventilation resistance, is supported by a collar-shaped insulator 6, and is insulated so as to block the gas flow. A negative DC high voltage is applied to the ground from the power source 39 through the conductor n and the insulator tube 28, and this causes the grounded tape-shaped corona discharge electrode 4 to
A strong positive corona is transmitted from the corona generation part 17 to the counter electrode 4.
′, a strong ion wind is generated in the direction of the arrow, blowing the gas inside the duct 1, and at the same time, the gas population 2 causes the injection of fine particle ions introduced into the inside of the reduct 1 along with the gas flow. It becomes strongly positively charged by the shock. Reference numeral 37 denotes a dust collecting section, which is based on the part proposed by the inventor in his separate invention "Electrostatic Precipitator" (Japanese Patent Application No. 53-87319 and Japanese Patent Application No. 53-91560). A dust collection section is used. That is, 58.58', 59.
59', . . . are plastic sheets laminated at small intervals, and a conductive layer 58a is formed on only one side of each sheet that does not face each other.

58'a, 59a+59'a+... are formed, and these conductive layers are formed slightly inward from both edges 60 and 61 of each sheet to prevent corona generation at the edges. And every other adjacent one has a conductor.

The conductive layers 58a-59a are connected between the DC high-voltage power sources via the insulator pipe 35.
A DC voltage is applied between -... and ss'a-59'a-..., and the sheet μs, 5B', 59
．． Since a DC electric field is formed in the gas passage between 59', .

In this case, since adjacent conductive layers do not come into contact with each other, even if the sheet spacing is extremely small, a high voltage can be stably applied between the conductive layers, improving dust collection performance even if charged particles are deposited on one side. The electric charge leaks to the conductive layer on the back of the sheet due to the slight surface conductivity caused by the moisture adsorption layer that naturally occurs on the plastic surface, and the electric charge accumulates on the non-conductive side of the sheet, causing the dust collection space between the sheets to leak. If the electric field weakens over time and the dust collection performance deteriorates over time, the phenomenon will no longer occur. The clean gas from which fine particles have been removed is discharged to the outside from the gas outlet. [Effects of the Invention] The present invention has the above-described configuration.

The amount of air blown is significantly increased, and the generation of ozone associated with corona discharge color can be almost completely prevented.

[Brief explanation of drawings]

Fig. 1 is a horizontal sectional view of an embodiment of the present invention, Fig. 2 is a perspective view of the corona discharge electrode portion thereof, and Fig. 3 is a horizontal sectional view of another embodiment of the invention. 5 is a perspective view of the tape-shaped corona discharge electrode portion, and FIG. 6 is a perspective view showing details of the inside of the tape-shaped corona discharge electrode. FIG. 7 is a horizontal sectional view of another embodiment of the present invention. １・・・・・・・・・・・・Duct 2・・・・・・
・・・・・・・・・Gas inlet 3・・・・・・・・・・・・
・・・・Gas outlet 1・・・・・・・・Corona discharge electrode part 4′・・・・・・・・・Tape-shaped corona discharge electrode part 5.5′・・・・ Opposed Electrode 7...Ion Φ catcher 8,
9... Wire mesh 12.12... Current-carrying conductor 16... Thin wire heating element 17... Corona generation part 19.20
...Plastic membrane 5...Heating power supply, 36...High voltage power supply 31, 31', 32.32'...Parallel plate Electrode group 37...... Between dust collection parts, 3
9...DC high voltage power supply 40.41...Heat-resistant plastic tape 42.
・・・・・・・・・Metal tape, 58', 5
9.59'...Plastic sheet s8a+ 58
'a+ 59a, 59'a... Conductive layer or more

Claims (7)

[Claims] (1) A corona discharge electrode is provided on the upstream side of the box through which gas passes, and a counter electrode that allows free flow of gas is placed on the downstream side, insulated from each other, and a voltage is applied between both electrodes to discharge the gas. A high-voltage power supply is provided to generate corona discharge from the corona discharge electrode toward the counter electrode, and gas is blown from the corona discharge electrode side to the counter electrode side using the ion wind accompanying the resulting corona discharge. A corona blower characterized in that the corona blower is provided with means for heating the corona discharge electrode. (2) The corona type blower according to claim 1, wherein the means for heating the corona discharge electrode is an energizing means including a power source for energizing the corona discharge electrode. (3) A corona type blower according to claim 2, characterized in that a portion of the corona discharge electrode other than the corona generating portion is covered with a heat-resistant blanket. (4) The heat-resistant tape is two heat-resistant plastic tapes, and the corona discharge electrode is a thin metal tape,
It is shown that it is sandwiched and heat-sealed between the two heat-resistant plastic tapes and embedded between them so that only the downstream periphery thereof is exposed toward the counter electrode and forms a corona generation area. A corona type blower characterized by the features set forth in claim 3. (5) A corona discharge electrode is provided on the upstream side of the box through which gas passes, and a counter electrode that allows free flow of gas is placed on the downstream side, insulated from each other, and a voltage is applied between both electrodes to discharge the gas. A high-voltage power source is provided to generate a corona discharge from the corona discharge electrode toward the counter electrode, and a means for heating the corona discharge electrode is provided, thereby blowing gas from the corona discharge electrode side toward the counter electrode side. The corona type blower according to claims 1 to 4 is formed, and the fine particles suspended in the gas are precharged by ion bombardment between the two electrodes, and the counter electrode is further charged. An electrostatic precipitator is provided on the downstream side, consisting of a group of parallel plate electrodes arranged parallel to the gas flow, and a high-voltage power source is provided to apply a voltage between the adjacent electrode groups. An electrostatic precipitator for a place that is characterized by being equipped with one. (6) An electrostatic precipitator according to claim 5, characterized in that the parallel plate electrode group consists of a group of adjacent metal plate electrodes disposed in parallel and insulated from each other. (7) The parallel plate electrode group is an electrode group formed by laminating plastic sheets each having a conductive layer formed on one side at a distance from each other so that the conductive layers do not face each other. An electrostatic precipitator according to claim 6.