JPH02500727A - Electrostatic precipitator for use with electrofilters - Google Patents

Abstract

An electrostatic precipitator intended for use with electrofilters comprises a plurality of electrically conductive or semi-conductive plate-like or lamella-like precipitation electrodes (1, 2) which are arranged in mutually parallel spaced relationship. The electrodes (1, 2) are connected alternately to the one and the other terminal of a d.c. voltage source (3) by bringing an edge-surface part of those electrodes which are connected to one and the same terminal into pressure-contact with one side of a sheet-like or strip-like member (4 or 5) which is made of a highly resistive, antistatic material. The opposite side of the member (4, 5) has provided thereon an electric contact means (6 or 7) which is connected electrically to the relevant terminal of the d.c. voltage source (3), preferably through a high ohmic resistance (8 or 9).

Description

[Detailed description of the invention] Electrostatic Precipitator for Use in Electrofilters This invention is an electrostatic filter, This invention relates to electrostatic precipitators for use in electrofilters.

In principle, electrostatic precipitators are electrically conductive or semiconductive, parallel spaced multiple terminals arranged in parallel and electrically connected alternately to respective terminals of the DC voltage source. An air carrier containing several electrode plates or thin electrode plates connected to both terminals of a DC voltage source. Create a structural device similar to pacita. This type of electrostatic precipitator is equipped with a filter. The electrode plates or lamellas extend across an air duct or airflow path that is in such a manner that it is parallel to the direction of the air flow passage or duct of the electrofilter.

an air stream in which aerosol pollutants present in the form of solid particles or liquid droplets are purified is carried through airflow ducts, and blowers or fans, natural air circulation, Forced ventilation or electrically ionized air (see international patent application PCT/5E85100538) passing through the precipitator by means with the aid of Electrofilter collects electrostatic dust Incorporating the upstream device means can be done in any suitable known way, e.g. for emitting atmospheric ions. Aerosol contaminants present in the airstream are electrically removed by means of corona discharge. This is to electrically charge the battery. The purpose of an electrostatic precipitator is to remove the electrical band in the airflow passing through the precipitator. Electrolytic contaminants are generated between the various plate electrodes, between adjacent electrodes, and in the air flow. By bringing it under electrostatic induction of an electric field extending essentially at right angles to the direction , so that the contaminant can be placed on one side or the other of the electrodes depending on the electrical polarity of the contaminant. or the other, settles on the electrode and purifies the airflow from the contaminants. Ru.

In order for this type of electrostatic precipitator to function with a high degree of efficiency, it is necessary to In order to be able to extract a significant proportion of the contaminants present, To generate a high electric field strength between the electrodes, i.e. to reduce the space between the electrodes. Therefore, it is necessary to generate a high voltage between adjacent electrodes.

However, with today's electrostatic precipitator construction, these requirements are very difficult to achieve. stomach.

In known electrostatic precipitators, the small space and high voltage between adjacent electrodes This results in an unacceptably high risk of glow discharges. Groups like this Low discharge occurs particularly at the edges of electrodes, which are usually made of thin sheet metal, and this phenomenon As a result of the method used to manufacture the electrodes, these edges are angular. This is especially a problem when the dust collector is not aligned or is not aligned, and when using a precipitator, the dust collection electrode cannot be It is further increased by the dirt that collects in the area. Such glow discharges cause high disturbance noise level (crackling and rattling) and furthermore introduces undesirable ozone Occasionally, they occur at unacceptable levels. Electrostatic precipitators are required in some way It will also be appreciated that a distance must be maintained. This is it When achieved with the help of electrically insulating spacers placed between each electrode, the The spacer inevitably gets dirty during use of the precipitator, and a creep charge builds up on the dirty surface of the spacer. The result is that a flow occurs. This creep current can be reduced by using very high quality insulators. Gradually destroys the spacer insulation unless it is Therefore, this type of Normal practice in electrostatic precipitators is to use electrically insulating spaces with short creep current paths. to avoid the need for relatively complex and therefore expensive It is to use a structure.

It is also understood that electrostatic precipitators exhibit significant capacitance. The electrodes of the dust collector If touched unintentionally, a strong capacitive discharge current will naturally be emitted. this current can be very unpleasant and even dangerous. Therefore, this kind of electronic Do not use the Trofilter in a human environment, such as a home or work environment. It should be ensured that electrostatic precipitators are not touched unintentionally. this In the construction of the electrofilter, other structural requirements, e.g. small dimensions , often make conflicting demands such as low airflow resistance.

It is therefore one object of the present invention that the aforementioned problems and difficulties be overcome and that the introduction An object of the present invention is to provide an electrostatic precipitator of the type described in the part, wherein an adjacent Allowing higher voltages and smaller mutual spacing between the electrodes, thereby to separate electrically charged aerosol contaminants from the airflow through a precipitator or filter. , more efficiently than can be achieved with known electrofilters of this type. can.

This purpose is to ensure that the electrodes connected to one terminal of the DC voltage source are at least, up to now Instead of being connected directly to each other one by one as in the known electrostatic precipitators, the ends in that it is connected to its children individually, i.e. to each itself , achieved according to this invention. to said one pole of the electrode or dust collection element. Separate connections are made by making the side edges of each electrode from a highly resistive material. and another electrical contact hand electrically connected to the relevant terminal of the DC voltage source. a laminate-like or strip in which contact with said electrode is provided by steps This is achieved by placing the material in pressure contact with the respective sides of the member.

If the remaining electrodes are also connected to the other terminal of the voltage source in a similar manner, there are certain advantages is obtained. One terminal of a high voltage source is normally grounded, and it is also connected to a DC voltage source. the electrodes connected to the high voltage terminals at least individually in the manner described above, and Each is itself connected to the power source.

The aforementioned high-resistance materials are conveniently referred to as high-resistance plastics, the so-called Antistatic plastics or plastics treated to become antistatic, For example, packaging semiconductor components in such a way that the components are protected against the effects of electrostatic voltages. including plastic materials of the type used to Such as anti-static, or Antistatically treated plastic materials are available on the market and are typically It typically has a surface resistivity of 9 to 1015 ohms and approximately 1013 ohms.

According to the invention, the electrode connected to one terminal of the DC voltage source, i.e. If the ungrounded high voltage terminal of the recording source is connected at least through a very high resistance, electrically connected to the terminals and to each other. The result of electrical discharge from the electrodes and or along electrically insulating spacer members between adjacent electrodes with different voltages. These currents, which can occur as a result of creep currents, are very small. It is limited to small values, for example values of approximately 10 to 100 nA. Therefore before Such discharges may produce audible noise or emit undesirable levels of ozone. too small or negligible to occur and may occur Any creep current that does not occur is too small to have a detrimental effect on the insulating material. Giru. In practice, each electrode of an electrostatic precipitator constructed according to the present invention is very mild. Mild discharge and/or very low creep voltage along electrically insulating spacer members Automatically adjusts to individual voltage levels in response to current. two adjacent to each other Even direct short circuits between electrodes that do The precipitator can continue to function practically without interference. Wear. The invention also provides a strong relative discharge voltage that is the result of physically touching the electrodes. flow, thereby preventing other such unintended contacts from occurring. Eliminate the danger and discomfort that may occur.

This invention now relates to exemplary embodiments of electrostatic precipitators constructed in accordance with this invention. DESCRIPTION OF THE DRAWINGS FIG. 1 is described in more detail with reference to the accompanying drawings.

The only illustration in the accompanying drawing is the direction of airflow through the precipitator or electrofilter. 1 is a schematic diagram of an electrostatic precipitator of this invention; FIG. The air duct where the dust collector is located is Omitted from the drawings for brevity and clarity.

The illustrated precipitators are arranged in parallel and spaced relation to each other. consisting of electrodes 1 and 2, such as thin plates or plates of the sides of extend parallel to the direction of the airflow, i.e. at right angles to the plane of the drawing . These electrodes, or collection elements, are electrically conductive or semi-conductive. this At the point, the electric current carried by the electrode causes the electrical charge of the contaminant to settle on the electrode. It deals exclusively with the electrical charging of atmospheric ions that may be discharged in the vicinity of the electrode. Therefore, it is observed that it is very small. Therefore, electrodes 1.2 are made of metal. or a weakly conductive structure, such as a semiconductive paper or paperboard structure. It can be made from conductive or semiconductive materials. Each alternating electrode 1 of the precipitator ．． 2 are electrically connected to respective terminals or poles of a DC voltage source 3. this In the case of an exemplary preferred embodiment of the electrostatic precipitator of the invention, the collecting electrode 1.2 is connected to a voltage source. One side of each electrode is connected to one of each of the two terminals of 3. The edge surface or at least a portion of said side edge surface is made of a highly resistant material. , for example, so-called antistatic plastics or plastics made antistatic. Each of the sheet-like or strip-like members 4 or 5 made from This is achieved by pressing on one side. Such anti-static or Anti-static treated materials are well known per se and are used in the transportation of semiconductor components and Particularly important for wrapping semiconductor components to protect these components from electrostatic voltages during storage. It is used. These plastic materials are typically It has a surface resistivity of approximately 1013Ω.

Marketed by MAGNAB, Nykoping, Sweden under the name MPAC The antistatic materials described above have been found to be highly suitable for the requirements of this invention. . The plastic part 4.5 may have a thickness of 1 to 5 mm, for example, and The sides of pole 1.2 are pressed together with the respective plastic with the help of suitable applied pressure. It has a little elasticity so that it can make firm contact with one surface of the hook member. or elastic. On the mutually opposite side surfaces of the plastic part 4.5 The respective electrical contact means 6.7 are made of metal wires, metal strips, gold, etc. It is provided in the form of a metal plate, etc., and is pressed against the surface of each plastic member. and each of the DC voltage sources 3 suitably through a high ohmic resistor 8.9, respectively. electrically connected to the terminals of the

The relatively soft and elastic antistatic plastic member 4.5 is of good quality. Supported by respective rigid holders made of insulating plastic material] 0 and 11 If you do so, you will have certain advantages.

As a result of the arrangement according to the invention, each of the collecting electrodes 1.2 has a respective electrical charge. Through the very high resistance formed by the protective plastic parts 4 and 5, They are individually electrically connected to the relevant terminals of the DC voltage source 3. Plate electrode 1.2 and electrode In addition to being present between the relevant terminals of voltage source 3, this high resistance between the various electrodes 1.2 which are commonly connected to each other. therefore, These electrical discharges that can occur at the edges of electrodes 1.2 are of completely inaudible magnitude. and only to the extent that it does not produce appreciable amounts of ozone. Similarly, may occur along an electrically insulating spacer member between each electrode 1 and 2. No creep current is limited to very low values so insulator materials are not affected It will remain as it is. Furthermore, as a result of the invention, two mutually adjacent electrodes 1 and As a result of a direct short circuit between and 2, only very low short circuit currents can occur. actual , each individual electrode 1.2 has a general discharge current, creep current and related The short-circuit current through the electrode is automatically adjusted to the voltage level at which it is incidental. given Reducing the voltage level on one electrode does not affect the voltage level on the remaining electrodes and Therefore, it should not have any appreciable effect on the operation or efficiency of the electrostatic precipitator. stomach.

The particular construction of the electrostatic precipitator of this invention prevents the generation of large, dangerous, or unpleasant discharge voltages. Ensure that flow does not occur as a result of unintended physical contact with electrode 1.2. make it come true.

The main purpose of the high ohmic resistance 8.9 is that one of the plastic parts 4.5 is e.g. If a short circuit occurs as a result of unintentional contact with water, a large short circuit current will occur. The goal is to prevent this from happening.

As shown in the drawing, one terminal of the DC voltage source 3 is normally grounded. this In the case of an electrostatic precipitator assembled according to the invention, this grounded connection of the DC voltage source 3 It is conceivable to connect the terminals directly to the corresponding dust collection electrodes 2 by conventional methods. Ru. However, even in such a case, the grounded terminal of voltage source 3 is not shown in the drawing. High resistance anti-static or anti-static treated plastics as shown in It is preferable to connect to the associated electrode 2 through the contact member 5.

The arrangement of the collecting electrodes 1.2 of an electrostatic precipitator assembled according to the example shown is shown in FIG. The distance between the plastic member 4 and the Uβy electrode 2 connected to the member is Advantageously, it is greater than the distance of adjacent electrodes 1 and 2 from each other. that Correspondingly, the distance between the plastic member 5 and the electrode 1 is 1 and 2 from each other. This arrangement of electrodes allows electrode 2 and plastic direct sparks between the electrode 1 and the plastic member 4 and between the electrode 1 and the plastic member 5. prevent.

Electrodes 1 and 2 are connected to spacer members (not shown) made of electrically insulating material. ) is kept at the desired distance. spacer member Any creep current that may be carried through the Because they are always small and completely harmless, the configuration and There is a fairly wide range in terms of positioning, as well as the types of insulating materials used here. Given. Therefore, the spacer member should be made of a compatible moldable electrically insulating resin or or glue, and at a suitable position between the dust collecting electrodes 1 and 2. used.

The collecting electrode 1.2 of the electrostatic precipitator may be made of semiconductive paper or paperboard, for example. Therefore, the dust collector of the present invention can be manufactured simply and at low cost. this By means of which the precipitator can be made for one-time use, i.e. electrostatic precipitator , or if that part formed by electrode 1.2 is an old precipitator or electrode pad. If the dust collector becomes too dirty for efficient use, it should be discarded and replaced with a new dust collector or a new one. It can be replaced with a new electrode pack.

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Claims (6)

[Claims] 1. An electrostatic precipitator for use in electrofilters, which are arranged parallel to each other. are arranged in spaced relation to one terminal or the other of the DC voltage source (3). Multiple conductive or semiconductive plate electrodes electrically connected alternately to terminals Or in one containing thin plate dust collecting electrodes (1, 2), The electrode (1 or 2) connected to one terminal of the voltage source (3) at least The seamed surface of each electrode (1 or 2) is made of a highly resistant material. press against one side of a sheet-like or strip-like member (4 or 5) The highly resistive members are individually connected by means of which each electrode is connected to the high resistance member. separate from the location in contact with the component and connected to the associated terminal of the DC voltage source (3) electrical contact means (6 or 7) connected to the Features: Electrostatic precipitator. 2. All electrodes (1, 2) are connected to the respective terminals of the DC voltage source (3) in the manner described above. 2. A dust collector according to claim 1, characterized in that the dust collector is individually connected to. 3. The highly resistive material (4, 5) is between 109 and 1015 ohms, preferably approximately 1 Characterized by containing an antistatic plastic material with a surface resistivity of 01●Ω The dust collector according to claim 1 or claim 2. 4. The terminals of the DC voltage source (3) are connected to each other through a high ohmic resistor (8 or 9). Electrical connection of the member (4 or 5) with the respective contact means (6 or 7) The dust collector according to claim 1, characterized in that: 5. The high resistance members (4, 5) are characterized by being slightly elastic or soft. The dust collector according to claim 1. 6. The electrodes (1, 2) are intended with the aid of spacer members comprising electrically insulating material. characterized in that they are maintained in mutual positions according to any one of claims 1 to 5. Dust collector as described. 7. The spacer member is made of moldable electrically insulating plastic material or glue. The dust collector according to claim 6, characterized in that: