DE102020133670A1 - Electrostatic precipitator for cleaning and disinfecting gases - Google Patents

Abstract

Electrostatic separator for cleaning and disinfecting gases, comprising a housing (1) with a collecting container (8) for separated particles, at least two flow channels arranged in the housing with openings (23) on both sides, one corona discharge arrangement in each flow channel, comprising at least one corona discharge electrode ( 9, 10) and separating surfaces (11), suitable for forming a circumferential electric field (12) between the at least one corona discharge electrode and the separating surfaces, the separating surfaces being formed entirely or partially by the inner walls of the collection container, each of the flow channels having a flow deflection (6) below the corona discharge electrodes in or above the collection container, on each side of the flow deflections a vertically upwardly directed flow channel section (5, 7) connects, which opens out into one of the openings at the top of the housing and switches bare connecting means with switching positions for the serial and/or parallel connection of the flow channels between at least one gas inlet (2) and at least one gas outlet (3) in or out of the housing.

Description

The invention relates to an electrostatic separator for cleaning and disinfecting gases, preferably gases contaminated with particles such as pollutant particles, aerosols and/or pathogens such as viruses or bacteria, more preferably from technical processes.

Gases contaminated with particles and/or aerosols are, in particular, flue gases with solid and/or liquid components. They have a gaseous carrier component in which solid particles and/or liquid droplets are suspended. They are primarily produced in combustion processes, e.g. from small furnaces, ovens, combustion engines or other combustion systems.

Gases contaminated with pathogens such as ultrafine particles, viruses or bacteria are, in particular, gases that have come into direct or indirect contact with the aforementioned pathogens via a transmission medium and have at least partially absorbed them, preferably as solid and/or liquid or molecular components. They arise not only in technical processes such as in the food industry, in laboratories or canteen kitchens, but also in other processes such as in clinics, in the care sector or in animal husbandry.

It is known that electrostatic precipitators are particularly suitable for separating fine and ultrafine particles from an exhaust gas or air, with electric field forces and space charge phenomena acting on the impurities in an air flow. Electrostatic filters are operated with a low pressure drop, especially for the cleaning of large air flow volumes.

Electrostatic separators can be integrated into existing housings or into downstream cleaning stages of an incineration plant. On the other hand, electrostatic precipitators can also be integrated into the existing circulating air exhaust air ventilation systems.

From the CH 695 113 A5 electrostatic flue gas cleaning stage is known for small furnaces, in which an electrostatic precipitator is integrated into a furnace pipe.

From the DE 10 2019 105 776 A1 an electrostatic precipitator for cleaning flue gases is known. It has its own housing with a collection container for separated particles, a gas inlet and a gas outlet and a flow channel arranged in between in the housing and guided past the collection container with a corona discharge arrangement arranged in this. The electrically conductive and grounded separation surfaces are partly formed by the inner walls of the collection container. A preferred use of the electrostatic precipitator is the cleaning of flue gases from small combustion plants such as in particular combustion furnaces for biomass, coke, coal, fuel oils, wood, wood pellets or other fossil fuels.

From the EP 0 600 101 B1 a device for biological purification and filtration of air with an ionization stage is known. The ionization stage is used in a flow channel between a coarse filter and a fine filter and acts on a gas stream flowing through. It in turn consists of at least one pair of electrodes which are connected to the terminals of opposite polarity of a power source.

However, known electrostatic precipitators not only have the advantages of efficient cleaning, but also disadvantages. This includes complex maintenance as well as a large size and a pronounced risk of collected particles being entrained again by the cleaned gas with increasing flow rate. Furthermore, the condensation of gas components, in particular combustion gases, limits the operational stability and increases the susceptibility to damage.

Proceeding from this, one object of the invention is to provide an electrostatic precipitator for cleaning and/or disinfecting different gases, whereby it can be used flexibly, in particular in terms of the volume flow to be managed and/or in terms of the cleaning quality, and at the same time for use in confined spaces or emission-sensitive environments such as is suitable in buildings and is characterized by particularly safe handling.

The object is achieved by an electrostatic precipitator having the features of claim 1. Subclaims referring back to this reflect advantageous configurations.

An essential basic idea of the invention is to design an electrostatic precipitator with at least two flow channels equipped with electrostatic corona discharge arrangements in such a way that they can be connected to one another in series and/or in parallel between one or more gas inlets and between one or more gas outlets. If a large gas volume flow has to be cleaned and/or disinfected, a parallel connection is suggested. If, on the other hand, a high cleaning quality is required strives, it makes sense to conduct the gas flow in series through a plurality of corona discharge arrangements with a series connection of flow channels. To this end, switchable connecting means are proposed which have switching positions for the serial and/or parallel connection of the flow channels between at least one gas inlet and at least one gas outlet into or out of the housing. The property of the electrostatic precipitator as a flow switch between one or more selected gas inlets and one or more selected gas outlets is therefore within the scope of the invention.

With this flow switch, an electrostatic precipitator can advantageously not only be varied in the volume flow and/or in the cleaning intensity, but also individually adjusted to specific environment-specific requirements depending on the activation of gas inlets and gas outlets.

When the raw gas is passed through the corona discharge arrangements of the separator, the gas composition and the chemical gas components of the raw gas are preferably not changed. In this respect, a clean gas leaving the separator also includes cleaned exhaust gases, e.g. from a combustion process.

In principle, any gas that can be cleaned of particles or aerosols by the proposed corona discharge arrangement and/or can be electrostatically disinfected of germs such as viruses or bacteria is suitable as a raw gas introduced via the gas inlets. A raw gas is therefore not limited to particle-laden flue gases, for example from a combustion plant or a production process. Rather, within the scope of the invention, the possibility is also proposed of using a gas contaminated with pathogens such as bacteria or viruses with or without particles or aerosols as the raw gas. Consequently, a use of the electrostatic precipitator for the disinfection of gases is also proposed, for example for the disinfection of room air, especially in germ-sensitive areas such as (not exhaustively) in clinical areas, in the care sector, in the veterinary sector, in laboratories and clean rooms, in the food sector such as restaurants , canteens or in food production chains as well as in all crowds of people with increased crowds such as in public transport, elevators, trade fairs and markets or sports facilities in buildings.

The cleaned and/or disinfected raw gas leaves the separator as clean gas via at least one of the gas outlets into a gas post-treatment, into an exhaust gas system or, in the case of disinfection of ambient air, back into the environment.

The solution to the problem is based on an electrostatic precipitator for cleaning and disinfecting gases, comprising a housing with a collection container for separated particles, which can preferably be removed downwards, at least two, preferably exactly two, flow channels arranged in the housing and guided past the collection container, with openings on both sides, and one each Corona discharge arrangement in each of the flow channels. At least one of the flow channels, preferably all of them, are preferably routed through the collecting container. Each corona discharge arrangement comprises at least one, preferably two, disk-shaped corona discharge electrode and separating surfaces, suitable for forming a circumferential electric field between the at least one corona discharge electrode and the separating surfaces as counter-electrodes. In the case of several corona discharge electrodes, these are arranged in series in the flow channel in the direction of flow and are preferably electrically connected to one another.

The separation surfaces are formed by the inner wall areas of the flow channel. The separation surfaces in all flow channels are preferably grounded (zero potential), while the at least one corona discharge electrode is preferably connected to a preferably common high-voltage source and is subjected to a potential difference from zero potential, preferably a negative DC voltage potential. In this case, the housing or at least the inner walls of the flow channels or at least the separation surfaces are electrically conductive or have a conductive coating. In their entirety, the separating surfaces basically extend over all electrically conductive or conductively coated inner walls of each flow channel, which are preferably also electrically connected to one another and are thereby subjected to the same potential as one another.

In principle, the entire inner surface of the electrostatic precipitator forms the collection surface for particles: After passing through the gas inlet and before reaching the corona discharge arrangement, particles are initially separated from the gas flow as gas-dynamic and mechanical precipitation on the inner walls, in particular of the first flow channel section, due to gas-dynamic phenomena. When the gas flow reaches the first corona discharge electrode in a flow channel, the deposition takes place increasingly electrostatically in the corona discharge field, with the deposition of the particles in the Essentially takes place as particle deposits on the grounded inner wall areas. This deposition is repeated in the case of the second and possibly further corona discharge electrodes following the first corona discharge electrode.

Deposition also takes place on the surfaces of the corona discharge electrodes (gas-dynamic effects, mechanical collection and collection under the influence of electric wind). Particles are also deposited on the upward-pointing surfaces of the first and second and possibly following further disc-shaped corona discharge electrodes (gas-dynamic effects, mechanical precipitation, partial electrostatic precipitation of positively charged particles from the gas flow on the surface of the high-voltage electrode with negative polarity, precipitation by electrical Wind). Particles are deposited on the inner surface of the collection container, which is also grounded. This deposition occurs due to space charge effects by means of mechanical forces, thermophoretic forces, electric field forces between the inner surface of the collection container and the rigid support between the corona discharge electrodes. The inner walls of the second flow channel section following the corona discharge electrodes in the direction of flow also result in further deposition of charged particles under the influence of space charge effects.

In addition to gas cleaning by electrostatic separation, the gas flow in the flow channel is also disinfected in the electrostatic field in the corona discharge arrangement. In the case of a corona discharge, ozone is formed in an oxygen atmosphere and has an advantageous toxic effect on bacteria and viruses. The ozone kills in particular the bacteria and viruses, i.e. the pathogens that attach themselves to the surface of the particles separated on the separation surfaces. It is fundamentally irrelevant whether a corona discharge occurs with both negative and positive polarity. Preferably, however, the corona discharge is of negative polarity towards the deposition surfaces, since it is then characterized by higher discharge current levels, higher volumes of ozone generated, and long-term operational stability.

The killed pathogens are then forwarded to the collection container together with the particles (carrier particles) and discharged from the separator.

For use of the electrostatic precipitator as a room air cleaner or disinfection stage as a circulating air, supply air or exhaust air system, gas conveyance through the flow channels by means of separate gas conveying means such as a fan is particularly necessary and thus proposed if there is no pressure difference between the gas inlet and the gas outlet from the separator reigns.

If these gas conveying means are switched off and no gas stream flows through the electrostatic precipitator, a concentration of pathogens can occur in the separator. In order to avoid this, it is proposed to provide a corona discharge with a formation of ozone at preferably regular intervals, which collects in the separator and then in turn acts on the pathogens and kills them. The corona discharge in turn generates an electric wind inside the separator, which ensures ozone circulation and thus disinfection in the entire interior volume of the separator.

In principle, viruses and bacteria on aerosols or other charged carrier particles do not affect the efficiency of an electrostatic precipitator. In the usual ambient conditions for gas disinfection (<50°C), the generation of ozone during a corona discharge plays a crucial role in destroying bacteria and viruses. If there is no flow in the flow channel, the ozone, which is heavier than the oxygen or nitrogen in the atmosphere, accumulates in the collection container and ensures further disinfection of the particles cleaned there.

Preferably, at least one of the, preferably all, disc-shaped corona discharge electrodes are arranged in the collection container in each flow channel, ie they are not arranged inside the housing, but protrude at least partially out of the housing and into the collection container. The inner walls of the collecting container serve at least in part as separation surfaces and, if they preferably also serve as counter-electrodes for the corona discharge electrodes, have an electrically conductive and grounded surface. This means that the flow channels are routed through the collection container or touch it, at least in the area of the corona discharge arrangement. A further preferred embodiment of this is characterized in that only the areas on the separation surfaces with the shortest distance to one of the electrodes are formed entirely or partially, preferably predominantly, by the inner walls of the collection container. A further preferred embodiment of this is characterized in that only the areas on the separation surfaces with the shortest distance plus a maximum of 50%, more preferably 20%, more preferably 10% of the shortest distance to a have the electrodes, are formed entirely or partially, preferably for the most part, by inner walls of the collection container.

Each of the flow channels includes a flow deflection under the corona discharge electrodes in or above the collection container. On either side of the flow deflections, there is a flow channel section which is aligned vertically upwards and which opens out into one of the openings at the top of the housing. After gas enters through one of the openings, the flow channels first follow a downward-pointing first flow channel section downstream and opens from there into a flow deflection, from there into an upward-pointing second flow channel section of the flow channel and then out of a second of the openings serving as a gas outlet .

The disk-shaped corona discharge electrodes are preferably arranged orthogonally to the direction of flow in the flow channel, so that the flow of smoke gas in the flow channel is deflected by the electric field as uniformly as possible over the entire field. In order to generate a uniform electric field strength over the entire field, it is proposed that the shortest distance between the peripheral edge of the corona discharge electrode and the nearest inner wall is preferably the same in each case. Accordingly, the electric field between the peripheral edge of a corona discharge electrode and the respective shortest distance to the inner wall is at its maximum. The corona discharge electrodes are preferably disc-shaped.

A preferred embodiment of the electrostatic precipitator is characterized in that the two flow channel sections of the flow channels are arranged parallel to one another, the two flow channel sections of the flow channels preferably being aligned vertically and/or the at least one corona discharge electrode being aligned horizontally.

The collection container is preferably pot-shaped in extension to the housing and can be connected to the housing in a sealing manner via a mechanical lock, preferably a bayonet lock. The collection container has an internal volume that preferably includes the volume for all flow deflections. The flow deflections are preferably separated from one another by partition walls. In the area of the collection container, the partitions are preferably also part of the collection container, with these more preferably flush and sealingly adjoining the partitions in the interior volume of the housing.

A preferred embodiment of the at least one disk-shaped corona discharge electrode per flow channel is characterized in that it has electrode tips that protrude radially all the way around, the distance between the electrode tips being the shortest distance and preferably being the same size in each case from the closest separation surface.

Within the scope of a preferred embodiment, the corona discharge arrangements each comprise two corona discharge electrodes which are each arranged in series in at least one flow channel, more preferably in all flow channels. The two corona discharge electrodes are arranged in series in the respective flow channel. More preferably, a corona discharge electrode is arranged before and after the respective flow deflection above the collection container. More preferably, the respective two corona discharge electrodes of a flow channel are connected to one another by an electrically conductive, rigid carrier along the flow deflection. In principle, the corona discharge arrangements can be combined with further corona discharge electrodes as part of a serial arrangement.

Each flow channel has two openings, each serving for a gas inlet and a gas outlet, and preferably opening into an antechamber volume for the at least one gas inlet or at least one gas outlet. A direction of flow is not specified in principle; it is determined by a respective serial and/or parallel interconnection of the flow channels and thus of the openings with one another. For this purpose, switchable connecting means with switching positions for the serial and/or parallel connection of the flow channels between at least one gas inlet and at least one gas outlet in or out of the housing are provided. Between one, preferably each of the at least one gas inlet and one, preferably each of the at least one gas outlet, there is on the one hand the possibility of a switchable fluidic connection by means of the aforementioned connection of the flow channels and on the other hand the possibility of a selective closure of the gas inlets and the gas outlets, with at least one preferably exactly one gas inlet and at least one gas outlet must remain open. A preferred embodiment of the switchable connecting means provides closure flaps on the openings, gas inlets and gas outlets, preferably each opening, each gas inlet and each gas outlet, which can be switched back and forth independently between two switching positions, an open position and a blocked position.

The gas inlets and gas outlets form the interfaces between the electrostatic precipitator and the environment, preferably an exhaust air duct system or another exhaust air or intake volume, for example in a building. Their function, ie the direction of flow, is fundamentally reversible, ie gas inlets can be switched to gas outlets and vice versa and can be used. Likewise, individual gas inlets and gas outlets can be closed, so that although a flow channel opens into the antechamber volume, the gas flow from it is passed on to another flow channel.

A preferred embodiment consequently provides an electrostatic precipitator on which a switchable connecting means of the aforementioned type is provided at each gas inlet and at each gas outlet. This means that each gas inlet and outlet can be switched on or closed individually. The electrostatic precipitator can also be used as a flow switch between the at least one gas inlet and at least one gas outlet.

A further preferred embodiment provides that one switchable connecting means is connected to at least one opening of one, preferably all, of the flow channels.

A further preferred embodiment provides a switching position in which one, preferably only one, gas inlet is connected to one, preferably only one, gas outlet only via a parallel connection of at least two flow channels. The flow cross sections of the flow channel cross sections add up, which increases the volume flow capacity of the electrostatic precipitator accordingly.

A further preferred embodiment provides a switching position in which one, preferably only one, gas inlet is connected to one, preferably only one, gas outlet only via a series connection of at least two flow channels. A series connection advantageously effects cleaning and/or disinfection in several stages in succession. A total flow resistance that increases with the number of flow channels through which flow occurs in series can be reduced overall by an optional combined parallel and series connection of flow channels. Likewise, within the scope of a further optional embodiment, the dwell time available for cleaning or disinfection in a selected flow channel of a flow channel row can be increased by connecting this in parallel with another flow channel, and the flow rate can be reduced.

A further preferred embodiment provides for a cylindrical inner volume of the housing.

For the realization of several preferably parallel flow channels, at least one axially oriented partition is preferably provided in the housing, which separates the flow channels in the inner volume from one another. The partition walls form part of the wall of the flow channels. At least in the area of a corona discharge arrangement, the partitions are preferably designed with electrically conductive and grounded surfaces (zero potential) as part of the separation surfaces.

The corona discharge electrodes are preferably fixed in the respective flow channels by a rigid high-voltage line in each case and connected to a high-voltage source outside the housing via this line. In each flow channel there is at least one corona discharge electrode, preferably two corona discharge electrodes, more preferably arranged on both sides of the flow deflection and each mechanically positionable and electrically connected in the flow channel via a rigid high-voltage line. The high-voltage lines are preferably arranged coaxially in each flow channel cross-section, preferably vertically between the outlet line and the nearest electrode. More preferably, the rigid high-voltage lines are each inserted and aligned axially in one of the flow channel sections aligned vertically upwards.

The rigid high voltage line terminates at a first corona discharge electrode. In the case of several corona discharge electrodes, which are preferably arranged one behind the other in the flow direction in the flow channel, the corona discharge electrodes are connected to one another by an electrically conductive rigid connection, such as a rigid metal support.

The rigid high-voltage line is preferably aligned axially in one of the two flow channel sections, i.e. with its free end facing downwards, and has no electrical contact with the inner wall. More preferably, the distance from the high-voltage line to the inner wall apart from at least the corona discharge electrode is always greater than the aforementioned shortest distance from the peripheral edge of the corona discharge electrode to the nearest inner wall in order to avoid deposits.

It goes without saying that the high-voltage line and the electrically conductive Inner walls of the flow channel are electrically isolated from each other, an aforementioned potential difference between the corona discharge electrode and the inner wall as a separation surface is possible at all.

The high-voltage lines are preferably routed out of the flow channels via a gas-impermeable high-voltage line bushing away from, preferably above, the openings. To reduce the risk of contamination from deposits from the flue gas to be cleaned on the inner walls and the high-voltage lines and thus a fundamentally possible risk of short circuits, the gas-impermeable high-voltage line bushing is provided away from the gas inlet through an opening in a flow channel section.

A tubular electrical insulator is preferably also arranged around the high-voltage line on the high-voltage line in the flow channel itself. Preferably, these insulators extend from the gas-impermeable high-voltage line bushings to just before or to the nearest electrode, thereby electrically isolating the high-voltage lines from the respective surrounding flow channel section. The tubular electrical insulators also serve to improve the operational stability of the separator, to lengthen the lengths of the insulating surfaces between the aforementioned separation surfaces and the high-voltage lines, and to reduce electrical leakage currents.

In order to prevent the risk of a short circuit at the end of the insulator, another embodiment proposes designing the tubular electrical insulator in such a way that it has an inner diameter larger than the outer diameter of the rigid high-voltage line. There is play between the high-voltage line and the tubular insulator and thus a circumferential gap, with the tubular electrical insulator advantageously being suspended from the gas-impermeable high-voltage line bushing and the gap thus only being open at the bottom. This gap, particularly when the width of the gap changes during operation, fundamentally makes it more difficult to obtain a continuous coating of deposits across the transition between the insulator and the high-voltage line across the open end of the gap. The tubular insulator preferably consists of a tube made of an elastic or flexible material, preferably a silicone, a material containing silicone or another temperature-resistant elastic material. Alternatively, the tubular insulator can be fixed elastically in the aforementioned suspension. This has the advantageous effect that the insulator is moved relative to the high-voltage line by the inflow of smoke gas, as a result of which the aforementioned gap changes dynamically with the inflow and possible deposits in and on the gap are loosened. Since the high-voltage line with the insulator in the surrounding flow channel section is arranged from above on the high-voltage line bushing down to the gap, the loosened deposits in the gap are transported out of the gap down by gravity alone and the gap is thereby stabilized.

The tubular electrical insulator preferably ends at a predefinable, fixed distance before it is reached, ie above a closest first of the at least one corona discharge electrodes. This prevents the particles deposited as bulk material on the first of the at least one corona discharge electrodes from reaching the lower end of the insulator and possibly causing a short circuit or a leakage current path. This bed is formed on the surface of the corona discharge electrode pointing upwards, in that particle masses discharged from the gap or directly from the flue gas accumulate there. Said fixed distance preferably corresponds to between 10%, 20% or 30% to 50%, 70% or 80% of the maximum dimension of the first of the at least one disc-shaped corona discharge electrode. For electrostatic precipitators for small furnaces, ovens, internal combustion engines with exhaust gas flow volumes in the range between 20 and 300 m ³ /h, the fixed distance is typically between 2 and 15 cm.

An optional temperature sensor for the flow channel is advantageous for the operation of the electrostatic precipitator, in particular for flue gas cleaning from combustion processes. Depending on the flue gas temperature, the flue gas cleaning can be activated or deactivated by applying an HV voltage to the at least one corona discharge electrode. The temperature is preferably detected by at least one temperature detection sensor in the first flow channel section or on the housing near the first flow channel section.

During the operation of the electrostatic precipitator for flue gas cleaning, there is a risk that additional small amounts of condensate will form on the inner walls of the flow channels, especially in the start-up phase before an operating temperature is reached, especially on even colder areas of the inner wall, which, however, will be caused by the hot gas again during ongoing stationary operation be evaporated and so the process stability of the electrostatic deposition affect it only insignificantly. If the temperature conditions in the two flow channel sections do not permit evaporation, the condensates flow, driven by gravity, preferably steplessly and vertically downwards directly into the collection container. It is optionally proposed to switch the high voltage through to the at least one corona discharge electrode only above 50° C. to 70° C., preferably above 60° C., measured with the temperature detection sensor in the first flow channel cross section, and thus to activate the electrostatic separation.

• 1 in einer prinzipiellen Schnittansicht durch einen elektrostatischen Abscheider entlang eines von zwei Strömungskanälen (Prinzipskizze),
• 2 eine schematische Schnitt-Draufsicht einer Ausgestaltung eines elektrostatischen Abscheiders mit vier Strömungskanalabschnitten (gemäß 1), die durch Trennwänden voneinander abgetrennt sind,
• 3a bis c drei Ansichten einer Ausgestaltung des Ausführungsbeispiels eines elektrostatischen Abscheiders mit vier Strömungskanälen und zwei Koronaentladungsanordungen gemäß 1 und 2,
• 4a bis g prinzipielle Verschaltungs- und Einbauvarianten des Ausführungsbeispiels gemäß 1,
• 5a bis e mögliche Ausgestaltungsvarianten für einen elektrostatischen Abscheider mit zwei in Reihe geschalteten Strömungskanälen mit einer gemeinsamen Öffnung, die durch einen Durchbruch in der Trennwand zwischen den Strömungskanälen gebildet wird sowie
• 6a bis d eine optionale Ausgestaltung des Abscheiders, wobei jeweils zwei Koronaentladungselektroden aus benachbarten Strömungskanälen mittels einer Vergabelung elektrisch miteinander verbunden.

The invention is explained in more detail using further exemplary embodiments, the following figures and descriptions. All of the features shown and their combinations are not just limited to these exemplary embodiments and their configurations. Rather, these should be viewed as representative of other possible configurations that are not explicitly shown as exemplary embodiments and can be combined. Show it

• 1 in a basic sectional view through an electrostatic precipitator along one of two flow channels (schematic sketch),
• 2 a schematic sectional top view of an embodiment of an electrostatic precipitator with four flow channel sections (according to 1 ), which are separated from each other by partitions,
• 3a until c 3 views of an embodiment of the embodiment of an electrostatic precipitator with four flow channels and two corona discharge arrangements according to FIG 1 and 2 ,
• 4a to g basic wiring and installation variants of the embodiment according to 1 ,
• 5a to e possible design variants for an electrostatic precipitator with two flow channels connected in series with a common opening which is formed by an opening in the partition wall between the flow channels and
• 6a until i.e an optional refinement of the separator, in each case two corona discharge electrodes from adjacent flow channels being electrically connected to one another by means of a bifurcation.

1 shows a basic sectional view, not to scale, through an electrostatic precipitator to explain the basic structure, the section running along one of the at least two flow channels. Shown is a housing 1 of the electrostatic precipitator with the flow channel, comprising a flow deflection 6 with flow channel sections 22 adjoining on both sides, as a fluidic connection between two openings 23. The flow direction 4 in the flow channel, shown with arrows, is not fixed, but depending on the switching position of the in 1 The connecting means, not shown in detail, can be adjusted and determines the respective openings for a gas inlet and a gas outlet in the first and second flow channel section 5 or 7. The flow channel sections 22 (ie 5 and 7) of the flow channel are on both sides for deflecting the flow and preferably as shown at least for the most part part arranged vertically. The housing 1 of the illustrated embodiment itself is open at the bottom, but is closed off from the outside by a collection container 8 which closes the opening and has handles on both sides.

In favor of a compact structure, the two flow channel sections 22 are arranged parallel to one another, more preferably vertically parallel to one another. There is a partition wall 14 between the two flow channel sections. This ends at the bottom before reaching the flow deflection 6.

The housing 1, the partition 14 and/or the collection container 8 are preferably made of metal in the exemplary embodiment. They are preferably grounded or at least connected to a common electrical potential. In the illustration, the circumferential lines or separations of the individual components are not drawn in to emphasize the continuous flow channel.

Furthermore, in each flow channel of the in 1 In the illustrated embodiment, a corona discharge arrangement is provided with two disc-shaped corona discharge electrodes 9 and 10 and separating surfaces 11, each suitable for forming a circumferential electric field 12 between the corona discharge electrode and the separating surfaces. As shown, the two corona discharge electrodes are preferably arranged one in front of and one after the flow deflection 6 in the direction of flow 4 . More preferably, the at least one corona discharge electrode is aligned orthogonally to the two flow channel sections. With a vertical alignment of the flow channel sections mentioned, the disk-shaped corona discharge electrodes are aligned horizontally.

The corona discharge electrodes 9 and 10 are preferably not in the housing as shown 1 itself arranged, but protrude downwards out of the housing 1, ie they are arranged inside the collecting container 8. Likewise, the areas on the separation surfaces with the shortest distance to one of the electrodes are at least partially formed by the inner walls of the collection container.

The two corona discharge electrodes 9 and 10 preferably have electrode tips that protrude radially in the direction of the separation surfaces, around which the field strengths of the electric field 12 are at a maximum. These electrode tips are preferably each at the same distance from the respectively closest deposition surface, so that the electric fields have approximately the same field strength over the entire circumference of the corona discharge electrodes.

The two corona discharge electrodes 9 and 10 are also, as in 1 also shown, connected to one another by an electrically conductive rigid carrier 13 along the flow deflection 6, so that one and the same electrical potential is present at these. The rigid carrier is only connected to the corona discharge electrodes (electrically conductive), positions them relative to one another in the flow channel and preferably has no connection to other components, in particular to the inner walls of the flow channel, particularly in the area of the flow deflection 6 . The carrier is preferably a sheet metal carrier, the sheet metal being arranged as upright as possible, ie vertically, and as axially as possible in the flow channel in the area of deflection 6 to avoid or reduce deposits of particles.

Furthermore, in 1 a rigid high-voltage line 15 is arranged axially in the flow channel section 5 (or alternatively 7), which serves both as a support element for fixing the corona discharge electrodes 9 and 10 in the flow channel and as an electrical connection of these to a high-voltage source 16. The high-voltage line is preferably fed through a high-voltage line bushing 17 with a preferably ceramic element 18, alternatively a glass element as an electrical insulator to the housing 1 from the upper end of the first flow channel section 5 (in 1 ) discharged and held. Furthermore, an elastic or flexible tubular electrical insulation, preferably a silicone tube 19, is provided around the high-voltage line, which has a larger inside diameter than the outside diameter of the high-voltage line, forming an annular gap. The hose end of the silicone hose 19 ends at a fixed distance above the first corona discharge electrode 9. The distance preferably exceeds the maximum possible bed height of the particle bed on the first corona discharge electrode 9, so that between the particle deposits on the silicone hose 19 at the lower hose end 20 and the aforementioned particle bed on the first corona discharge electrode 9 to avoid short circuits always remains a distance.

The charging of the corona discharge electrodes by the high-voltage source 16 is preferably temperature-controlled, with a potential difference being fed in only above an adjustable operating temperature. It is proposed to carry out at least one temperature measurement in a flow channel section, in the example shown the flow channel section 5 above the associated opening (in the example of the gas inlet 2). This is done by means of a temperature detection sensor 21 either selectively, as in 1 shown, in the inner volume or alternatively integrally over the wall surface on the upper wall of the flow channel section 5 near the high-voltage line bushing 17.

Flowing around the elastic or pliable tubular electrical insulation, preferably the silicone hose, with smoke gas advantageously causes a continuous or recurring movement of the hose end around the high-voltage line. The associated constant changes in the width of the gap in the area of the hose end 20 leads to particles being detached from particles deposited on the hose and/or high-voltage line, particularly in the gap. The detached particles or particle agglomerates then fall, following gravity, onto the top of the first corona discharge electrode 9.

A preferred embodiment of the aforementioned compact structure shows 2 . she sees this in 1 illustrated housing 1, which encloses a cylindrical inner volume with partitions 14 for two flow channels, which are separated from one another by radially erected partitions 14. The flow channels each connect two openings 23 (once for a gas inlet, once for a gas outlet) with one another, with a dividing wall between the two flow channels 24 preferably extending over the entire interior volume including that of the collecting container 8 (cf. 1 ), ie also extends between the two deflection areas 6 of the flow channels. The partition walls between the two flow channel sections 25 of a flow channel each end above the deflection areas 6 (cf. 1 and 4e) . The openings 23 each open into common antechamber volumes 28 of connection housing 29. Preferably, in these Antechamber volumes the switchable connecting means, more preferably closure flaps with an open position and a blocked position at least at each opening, located. Depending on the switching position, the antechamber volume opens into an interface with the environment, ie a gas inlet or a gas outlet. Alternatively, the interfaces can be closed by closure flaps, with which a gas flow introduced via a flow channel into an antechamber volume is discharged again into another flow channel.

3a until c Figure 13 depicts three views of an embodiment of the previously described embodiment of a four flow channel, two corona discharge assembly electrostatic precipitator.

3a corresponds in perspective to the sectional view 1 However, in the embodiment shown, a separate cover 26 is provided for each high-voltage line bushing 17 (cf. also 3b and c ). The individual covers for each high-voltage line bushing separately allow within the framework of a special method implementation in an advantageous manner individual charging of the corona discharge electrode arrangements for each of the two flow channels with their own high voltage. If, for example, a switching position with serial connection of the flow channels is set by the switchable connecting means, which are preferably arranged in the connection housings 29 and are not shown in more detail (gas flow passes through two stages in series, see eg 4c ), a first cleaning of the gas stream that is passed through is recommended as part of a first run (first stage), whereby it is cleaned of particles. This first separation in turn enables the pre-cleaned gas flow to have a higher flashover resistance than the uncleaned raw gas before it enters the first stage. The high voltage can be increased correspondingly higher during a second pass (second stage) following the first pass through a flow channel in the electrostatic precipitator. In the second stage, for example, the components remaining in the pre-cleaned gas flow that pass through the first stage can only be cleaned or disinfected in the first place.

3b and c illustrate in particular the arrangement of the two flow channels 27 on both sides of the partition wall between these flow channels 24. 3b shows this in a view through the openings 23 into the two flow channels. Both flow channels are also in 3c each indicated by a double arrow, which reflect both possible directions of flow.

4a to e show basic wiring and installation variants of the exemplary embodiment according to the aforementioned figures.

4a and b show a parallel connection of the two flow channels 27 indicated by arrows between two interfaces, a gas inlet 2 and a gas outlet 3. The high-voltage line bushing 17 is preferably arranged in both flow channels above the first corona discharge electrodes 9 above the first flow channel sections 5, ie in the in a preferred Flow direction preferably arranged towards the gas inlet 2 facing areas. In this way, the silicone hose 19 is wrapped around the high-voltage line 15 (cf. 1 ) does not flow from below, which leads to a lower risk of contamination and thus to improved operational stability. 4b 10 also shows a preferred configuration of the preferably planar corona discharge electrodes 9 and 10, which are adapted in their lateral configuration to the walls of the respective flow channel section 5 or 6 in order to achieve a uniform distance from the separation surfaces.

4c shows an alternative switching position of the connecting means in the electrostatic precipitator, in which the gas inlet 2 and the gas outlet 3, both arranged on one of the two connection housings 29 arranged on the left, can be inserted into an exhaust pipe in alignment with one another. In the switching position, the two flow channels of the separator are connected in series with one another, with the course of the flow and the direction of flow 4 being highlighted by an arrow between the gas inlet and gas outlet. The antechamber volume 28 arranged on the left is divided into two partial volumes 30 by the connecting means. A partial volume connects the gas inlet 2 to an opening of the first flow channel arranged below, while the other partial volume connects an opening of the second flow channel arranged above to the gas outlet 3 . The antechamber on the right of the separator, on the other hand, is not divided, but connects the openings of the two flow channels with one another, as shown, without any further branching, gas inlet or gas outlet.

In an alternative embodiment according to 4d to f show the in 4c Arrangement shown with other switching positions and a further gas outlet 3 or gas inlet 2 also on the antechamber volume arranged on the right. This enables a flow course and a flow direction 4 highlighted by an arrow between gas inlets and outlets. The electrostatic precipitator can be used as a flow switch.

4d shows an embodiment with a switching position in which the in 4c gas outlet shown is preferably closed by closure flaps (closed gas outlet 31). Furthermore, the antechamber volume on the left is undivided. The gas outlet 3 is located here on the antechamber volume on the right, so that the flow runs parallel through both flow channels.

4e shows an embodiment with a switching position in which the in 4c illustrated gas inlet is preferably closed by closure flaps (closed gas inlet 32). The antechamber volume on the left is also undivided in this switching position. The gas inlet 2 is located here at the antechamber volume arranged on the right, so that the flow through both flow channels runs parallel to the gas outlet 3 at the antechamber volume arranged on the left.

4f shows an embodiment with switching position, in which the antechamber volume arranged on the left as in 4c shown is also divided and a gas inlet and gas outlet connected open to one of the two partial volumes. In addition, an additional gas inlet (a total of two gas inlets 2 ) for the introduction of a second gas flow 33 is provided on the antechamber volume arranged on the right, as in the aforementioned embodiment. This second gas flow is preferably mixed in the antechamber volume arranged on the right with the gas flow flowing in from the flow channel arranged below and conducted as a mixed gas flow 34 via the flow channel located at the top to the gas outlet 3 .

in the in 4a to f shown, the partitions between the two flow channels and the flow channel sections 24 and 25 preferably have the 4g outlined extensions in the housing 1 on. While the partition wall between the two flow channels 24 completely separates the inner volume into two parts, each for one flow channel 27, and extends over the entire height of the inner volume, the partition wall between two flow channel sections 25 ends above the respective areas for the flow deflection between the two flow channel sections 22.

5a to e possible design variants for an electrostatic precipitator with two flow channels 27 connected in series with a connecting common opening 23, which is formed by an opening 35 in the partition 24 between the flow channels (cf. esp. 5a and b).

5b until i.e show a specific configuration in three layers, in which a prechamber volume 28 with a subdivision 36 preferably extends in a straight line to the partition wall between the two flow channels 24. 5c shows this in a view through into the antechamber volume 28, 5d this in a sectional plan view through the antechamber volume.

5c also shows a preferred bayonet lock 37 for the collection container 8 on the downwardly open end of the housing 1.

5e In contrast, represents an alternative embodiment with separate antechamber volumes 28 for gas inlet 2 and gas outlet 3. Likewise, the high-voltage line bushings 17 for the high-voltage line are not arranged above a flow channel here, but above the partition wall between two flow channel sections 25. The high-voltage lines preferably branch in the interior volume of the housing into the two adjoining flow channel sections 22 and each serve separately as a holder for one in 5e Corona discharge electrode not shown. The design of the electrodes preferably corresponds to those in 3a and 4a electrodes 10 shown.

6a until i.e represents an optional embodiment with two flow channels and four flow channel sections 22, each with a corona discharge electrode 38. The housing 1 has a removable cover 39 for maintenance and cleaning purposes, in which the high-voltage line bushings 17, preferably with their own cover 26, are placed. What is special about this embodiment is that all the electrodes 38 are held and fixed in the respective flow channel section from above via their own high-voltage line 15 . This advantageously allows all the electrodes to be removed upwards from the flow channel sections by lifting off the cover.

Show a preferred embodiment of this 6a and b in detail. 6c shows this embodiment in a plan view. In this case, two electrodes, each with a high-voltage line, are brought together via a bifurcation 40 at a common high-voltage line bushing 17 and connected to a high-voltage source. For the realization of a bifurcation into two adjacent flow channels or flow channel sections, the respective partitions arranged between them must be bridged, in the figure example provided by an opening 41 in the partition between the flow channels 24, more preferably exclusively above the extension of the openings 23 in the housing 1 (cf. 6a and i.e ). However, these fluidic connections between the two flow channels limit the applicability to the operating modes and switching positions in which an exchange of gas components play only a minor role, such as in a parallel connection of the flow channels, such as based on the 4a and b described.

However, there remains a general advantage of subdividing several parallel flow channels (compared to a single channel with the same total flow cross section) of the larger separation surfaces available for a separation and the larger electric field areas available for a corona discharge.

In contrast, an alternative, optional configuration with one high-voltage line bushing for each of the high-voltage lines/electrodes does not require any of the aforementioned openings.

Reference List

1

Housing

2

gas inlet

3

gas outlet

4

flow direction

5

first flow channel section

6

flow deflection

7

second flow channel section

8th

collection container

9

first corona discharge electrode

10

second corona discharge electrode

11

separation surfaces

12

rotating electric field

13

rigid carrier

14

partition wall

15

high voltage line

16

high voltage source

17

high-voltage line bushing

18

ceramic element

19

silicone hose

20

hose end

21

temperature detection sensor

22

flow channel sections

23

opening

24

Partition wall between two flow channels

25

Partition wall between two flow channel sections

26

cover

27

flow channel

28

antechamber volume

29

junction box

30

Partial volume in the antechamber volume

31

Sealed gas outlet

32

Sealed gas inlet

33

Second gas stream

34

mixed gas flow

35

breakthrough through the partition wall 24

36

subdivision

37

bayonet lock

38

electrode

39

lid

40

allocation

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• CH 695113 A5 [0006]
• DE 102019105776 A1 [0007]
• EP 0600101 B1 [0008]

Claims (18)

Electrostatic precipitator for cleaning and disinfecting gases, comprising: a) a housing (1) with a removable collection container (8) for separated particles, b) at least two flow channels (27) arranged in the housing and routed past the collection container with openings (23) on both sides, c) one corona discharge arrangement in each of the flow channels, comprising at least one disk-shaped corona discharge electrode (9, 10, 38) and separation surfaces (11), suitable for forming a circumferential electric field (12) between the at least one corona discharge electrode and the separation surfaces, the Separation surfaces are grounded and are wholly or partially formed by the inner walls of the collection container, wherein d) each of the flow channels each comprise a flow deflection (6) under the corona discharge electrodes in or above the collection container, e) a flow channel section (5, 7, 22) directed vertically upwards is connected on each side of the flow deflections and opens out into one of the openings at the top of the housing, and f) switchable connecting means with switching positions for connecting the openings of the flow channels in series and/or parallel between at least one gas inlet (2) and at least one gas outlet (3) into or out of the housing. Electrostatic precipitator after claim 1 , characterized in that a switchable connecting means is provided at each gas inlet (2) and at each gas outlet (3). Electrostatic precipitator after claim 1 or 2 , characterized in that a switchable connecting means is connected to at least one opening (23) of a flow channel (27), preferably of all flow channels (27). Electrostatic precipitator according to one of the preceding claims, characterized in that the switchable connecting means closure flaps are provided on each opening (23), each gas inlet (2) and each gas outlet (3) which can each independently switch between two switch positions, an open position and a blocked position, can be switched back and forth. Electrostatic precipitator according to one of the preceding claims, characterized in that a switching position is provided which connects only one gas inlet (2) to only one gas outlet (3) only via a parallel connection of at least two flow channels (27). Electrostatic precipitator according to any of the above Claims 1 until 5 , characterized in that a switching position is provided which connects only one gas inlet (2) only via a series connection of at least two flow channels (27) with only one gas outlet (3). Electrostatic precipitator according to one of the preceding claims, characterized in that exactly two flow channels (27) with openings (23) on both sides are arranged in the housing (1) and guided past the collecting container (8). Electrostatic precipitator according to one of the preceding claims, characterized in that the housing (1) encloses a cylindrical inner volume, at least one axially oriented partition (24, 25) being provided, which separates the flow channels (27) in the inner volume from one another and preferably the partitions are designed with an electrically conductive and grounded surface as part of the separating surfaces (11). Electrostatic precipitator according to one of the preceding claims, characterized in that in each flow channel (27) at least one, preferably all, of the disk-shaped corona discharge electrodes (9, 10) are arranged in the collection container. Electrostatic precipitator according to one of the preceding claims, characterized in that in each flow channel (27) the at least one corona discharge electrode (9, 10, 38) is fixed in the respective flow channel by a respective rigid high-voltage line (15) and is connected via this to at least one high-voltage source ( 16) are connected outside the housing (1). Electrostatic precipitator after claim 10 , characterized in that the rigid high-voltage lines (15) are each arranged axially in one of the vertically aligned flow channel sections (5, 7, 22) and each open out via a gas-impermeable high-voltage line bushing (17) away from the openings (23). Electrostatic precipitator after claim 10 or 11 , characterized in that in each case a tubular electrical insulator (19) is arranged around the rigid high-voltage lines (15) in the flow channel. Electrostatic precipitator after claim 12 , characterized in that the tubular electrical insulators (19) each have an inner diameter larger than the outer diameter of the respective rigid high-voltage line (15), are suspended from the gas-impermeable high-voltage line bushings (17) and each consist of a hose made of an elastic or pliable material, preferably at least partly made of silicone. Electrostatic precipitator according to one of the preceding claims, characterized in that the corona discharge arrangements each have two corona discharge electrodes (9, 10), with a) one being arranged before and one after the respective flow deflection (6) and b) the two corona discharge electrodes (9 , 10) are connected to one another by an electrically conductive rigid carrier (13) along the flow deflection (6). Electrostatic precipitator according to one of the preceding claims, characterized in that two corona discharge electrodes (9, 10), preferably from adjacent flow channels, are electrically connected to one another with their respective high-voltage line (15) by means of a fork (40) in the housing (1) via a common high-voltage line bushing ( 17) are connected to a high voltage source (16). Electrostatic precipitator according to one of the preceding claims, characterized in that the at least one corona discharge electrode (9, 10, 38) has circumferential, radially projecting electrode tips, the distance (A) of the electrode tips from the nearest separation surface (11) being uniformly the same. Electrostatic precipitator according to one of the preceding claims, characterized in that the respective two flow channel sections (5, 7, 22) of the flow channels are arranged parallel to one another, with the respective two flow channel sections of the flow channels preferably being vertical and/or the at least one corona discharge electrode (9, 10 , 38) are aligned horizontally. Electrostatic precipitator according to one of the preceding claims, characterized in that the collection container (8) is pot-shaped as an extension to the housing (1) and can be sealingly connected to the housing via a mechanical lock, preferably a bayonet lock (37).

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