Fine dust separation device for small combustion plants

Description

[0001] The present invention relates to a device for filtering fine dust, in particular for small solid fuel combustion plants, in which separation of coarse dust and condensed aerosols (tars) is included.

[0002] Fine particulate matter emissions from small combustion plants such as individual room heaters, fireplaces, stoves, and small boilers have been the subject of intense public debate due to their health risks. Regulations have been enacted at both the federal and, in some cases, local levels, setting limits for particulate matter emissions from these plants. These emissions enter the atmosphere via the flue gas from the combustion plants. Flue gas refers to the gaseous product of combustion, primarily of solid fuels.

[0003] For example, German law stipulates that, from 2010 onwards, dust emissions from existing combustion plants must be limited to 20 mg / m³ of flue gas and from 2015 onwards for new combustion plants, in accordance with the First Federal Immission Control Ordinance (1. BImSchV). Different transitional periods apply to existing combustion plants, depending on their age.

[0004] The vast majority, i.e., 80-95% of the mass of particulate matter from wood-burning appliances, has a particle size of significantly less than one micrometer. Therefore, from a technical perspective, only electrostatic precipitation and filtration are suitable for separating these small particles. In well-supervised and maintained industrial operations, these processes can achieve submicrometer separation efficiencies of approximately 95% for electrostatic precipitators and over 99.5% for filtering precipitators [Source: Fritz, W.; Kern, H.: Cleaning of Exhaust Gases, 3rd edition, 1992, Vogel Publishing House].

[0005] Coarse dust, which is also present in flue gas, can be separated much more effectively than fine dust. Explicitly mentioning the separation of coarse dust is not strictly necessary, as it is implicitly assumed that coarse dust will be separated if fine dust is separated. Organic components such as tars, which condense from the gas phase at lower temperatures, are also classified as fine dust due to the small size of the resulting aerosol droplets.

[0006] It is known that various dust separation systems for small combustion plants are available on the market, which can be retrofitted to existing plants, among other things. These are exclusively electrostatic precipitators, also known as electrostatic precipitators.

[0007] In these types of electrostatic precipitators (ESPs), an electrostatic field is generated in the gas stream to be cleaned via a high-voltage generator and a negatively charged spray electrode. This field causes dust particles to become electrostatically charged. Due to the electrostatic field forces, the negatively charged dust particles move towards a positively or neutrally charged collecting electrode, where they adhere to and are removed from the gas stream. ESPs available on the market for individual room heating appliances have a concentric design with a central spray electrode and use a flue pipe as the collecting electrode. Because of this geometry, the free flow cross-section decreases with increasing operating time due to the separation of fine dust from the gas stream and its accumulation on the walls of the flue.This increases the flow resistance of the flue gas, making maintenance in the form of manual cleaning, for example by the chimney sweep, necessary.

[0008] Particulate matter trapped within the flue gas path negatively impacts combustion operation and the efficiency of an electrostatic precipitator (ESP). Blockage of the flue gas path increases flow resistance, thereby restricting flue gas discharge and combustion operation. A growing layer of particulate matter on the flue gas path's (pipe) surface hinders the formation of the electrostatic field between the collecting and spraying electrodes, thus reducing the ESP's efficiency during operation. One ESP manufacturer already emphasizes the need for frequent manual maintenance in the operating and maintenance manual: manual cleaning must be performed up to several times a month.

[0009] The Federal Office for Economic Affairs and Export Control (BAFA) lists only electrostatic precipitators (ESPs) and no filters in its positive list for subsidies for particulate matter separators on small combustion plants, which was maintained until December 31, 2019 [Source: Funding overview: Heating with renewable energies]. Although it is generally known that filters in general, and depth filters in particular, have significantly better separation efficiency than ESPs, and although the legal basis for particulate matter separation on small combustion plants has been in force since March 22, 2010, and was known long before that, not a single (depth) filter system for particulate matter separation on small combustion plants has become established to date.

[0010] This illustrates that experts consider it impossible to reliably and with sufficient service life separate dust particles with simultaneous moisture from aqueous condensate and sticky components from tar-containing condensate in comparatively inexpensive small systems (costing only a few thousand euros for the end customer), requiring infrequent maintenance, without the constant monitoring during operation typical of industrial filters, and frequently passing through dew point and freezing limits, using (depth) filters. The prior art documents DE 10 2020 115589 A1, EP 3 834 910 A1, DE 10 2008 033737 A1, DE 10 2015 103337 A1 and WO 2008 / 010242 A1 are known.

[0011] One requirement of the invention is that the filter areas and housing dimensions should be as small as possible. It has been shown that with increasingly smaller filter areas, the susceptibility to difficult operating conditions increases, particularly the occurrence of disproportionately large quantities of tar and other condensed hydrocarbons, which can arise when burning excessively wet wood combined with very large logs and an overloaded combustion chamber. The aim of the development is therefore to identify these unfavorable operating conditions, to be able to demonstrate them, and ideally to limit them to such an extent that the filter area can be further reduced. The specific filter area [m² / kW], especially of the pre-filter, which is tailored to the heating output of the combustion system, can be reduced further the more these unfavorable operating conditions can be eliminated or at least limited.The closer one gets to this ideal case, the further the specific (pre-)filter area can move into the lower range of the possible interval (specified, among other things, in claim 1).

[0012] Monitoring the flue gas during operation is therefore an important step in detecting technical defects in the overall system (furnace, chimney) and also identifying user errors. The invention provides a simple, inexpensive, and robust concept for this purpose. The carbon monoxide (CO) content of the flue gas is monitored by means of sensors. To increase the service life of these sensors, the flue gas stream can preferably be diluted with air beforehand. Since the development of particulate matter is quite parallel to CO development, a CO measurement can provide good real-time information regarding particulate matter development. To protect the CO sensors from dust and tar, the flue gas is preferably first diluted and then passed over a depth filter material, preferably a packing of quartz wadding. The dust particles and tars deposited therein can then be determined gravimetrically by weighing.Based on the operating time of the flue gas analysis, a simple semi-quantitative statement about the amount of dust can be made, which, with some operating experience, allows at least a classification into low, medium, and high dust and tar loads. For details of the determination procedure, reference is made to the regulations of VDI 2066 / 1. The particulate matter determined in this way can contain the following components: mineral particulate matter, predominantly carbonaceous soot, and condensed hydrocarbons (tars).

[0013] Since tars condense at around 400°C and mineral dust and soot are significantly more temperature-resistant, the ratio of dust to tar and soot can be determined by heating the sample to, for example, 600°C, weighing it before and after. If, for instance, a combustion process resulted in a particularly high tar content due to operator error—for example, burning wet wood in excessively large pieces with an overloaded combustion chamber (i.e., with insufficient oxygen and at temperatures that were too cold and humid)—this will be reflected in the dust-to-tar ratio determined using the previously described thermogravimetric method. As a further refinement of the procedure, the heating process to vaporize the tars can be carried out under both oxidizing conditions (i.e., with air) and inert conditions (e.g., under a nitrogen atmosphere).

[0014] Furthermore, a flue gas cleaning device is known from DE 10 2008 059 432 A1, which is to be arranged in an exhaust gas duct and uses ceramic exhaust gas filters that are cleaned by flow reversal. A technical implementation is not known, in particular, none that is commercially available. It should be noted that, in principle, the amount of dust to be removed per heating season (i.e., the difference between the limit value and the raw gas dust concentration) is rather small for common combustion systems with low firing heat output, such as wood-burning stoves or pellet boilers, amounting to approximately 1 kg per heating season.

[0015] According to official sources such as the German Federal Ministry for the Environment (BMU) and the German Environment Agency (UBA), the average annual amount of particulate matter emitted per wood-burning stove in Germany is approximately 1.5 kg. This figure is based on a total emission of 17,000 tons of particulate matter per year from wood-burning stoves (according to BMU / UBA) and a number of approximately 11 million stoves (source: BMU, HKI eV for stove number - 17,000 t / 11 million stoves ∼ 1.55 kg on average across all stoves).

[0016] The separated soot load has a very low bulk density, which we determined to be approximately 55-60 g / l. Even though this value can vary, it equates to a bulk volume of about 25-30 liters of soot load to be separated per year for the average furnace in Germany. Even using the conservative standard value of 80 g / l for the bulk density of (industrial) soot, as found on Wikipedia, the volume to be separated is only about 20 liters. It is therefore clear that this volume cannot be retained in a flue pipe for a year until the next chimney sweep's inspection – either the cleaning and maintenance interval is considerably shorter, or the volume must be temporarily stored in a correspondingly large device, or cleaning must be carried out intermittently with batch removal from a correspondingly smaller storage volume.

[0017] The established filter technologies are technically complex and prone to failure, particularly due to the automated filter cleaning systems used. This is especially true for inexpensive, small-scale systems that lack the monitoring typical of industrial applications, require infrequent maintenance, and operate under conditions where both dew point and freezing limits are frequently encountered. The simultaneous separation of condensing tars significantly increases the amount of pollutants actually collected. While this positive side effect of dust separation is beneficial from an environmental and health perspective, it reduces the service life of the filter materials, which are subjected to considerably greater stress due to the larger quantities of contaminants collected.

[0018] Against this background, the object of the invention is to provide a dust separation device that is robust in its operating characteristics and insensitive to disturbances and incorrect operation, as well as having sufficiently long service lives without further maintenance.

[0019] To solve this problem, a device for filtering fine dust, especially for small solid fuel combustion plants, according to claims 1-10 is used.

[0020] According to the invention, as in Fig. 34As illustrated by way of example, the integration of a flue gas damper (24) is advantageously provided both in versions with an extraction (30) and filter unit (60) in one assembly and in a version in which the extraction and filter units are arranged in spatially separate assemblies (here without explicit illustration). The flue gas damper (24) is advantageously located above the extraction point, so that it at least reduces and ideally completely prevents the intake of false air or false gas from above. Fig. 34 For example, an electrostatic precipitator is used in the filter unit (60) and a collection chamber (26) is provided to receive the separated fine dust, which can optionally be emptied via a discharge (28).

[0021] They show Fig. 10 by way of example the embodiment of the invention with extraction unit (122) and filter unit (150) in one assembly and Fig. 33one version in two spatially separate arrangements of the extraction unit (30, analogous to 122) and filter unit (60, analogous to 150). In Fig. 33 It is also shown that the filter element (50) is located in the direction of flow between the inlet opening (66) and the outlet opening (68) of the filter unit (60).

[0022] According to the invention, given the comparatively small amounts of dust, the use of depth or storage filters is initially proposed as a simple, inexpensive and robust alternative to automatically cleaned filters.

[0023] Such storage or depth filtration is known, for example, from the field of purifying supplied breathing gases, such as in air conditioning or ventilation technology. In the case of fine dust particles from small combustion plants, filtering separators have a separation efficiency that is approximately 5 percentage points better than that of electrostatic separators – in industrial applications [Source: Fritz, W.; Kern, H.: Cleaning of Exhaust Gases, 3rd edition, 1992, Vogel Buchverlag]. According to the invention, a solution is therefore proposed that achieves both robust and reliable storage filtration and allows for fail-safe operation of the filter system.

[0024] According to the invention, the flue gas cleaning device, depending on its design, can be provided both for connection to chimneys of small solid fuel combustion plants, i.e., at the end of a flue gas path (on the roof, e.g., on the chimney as well as on or in the area around and also at least partially below the original chimney opening (before the installation of the particulate separator)), and for integration into the flue gas path, i.e., near the combustion chamber (downstream of the combustion chamber, i.e., still within the stove), between the stove and the chimney in the so-called connection or transition piece, under the roof or in the attic of a small combustion plant particularly suitable for solid fuels. An embodiment of the invention in a bypass to the aforementioned flue gas path is also considered integration into the flue gas path within the meaning of this invention.The flue gas from a combustion plant is introduced into the cleaning device realized by the device according to the invention, cleaned there and ultimately released into the environment.

[0025] Another embodiment of the flue gas cleaning device according to the invention comprises at least two spatially separated assemblies, namely the extraction unit and the filter unit, which are connected to one another by at least one connecting element (38 / 48), for example, an insulated metal hose, and sealed towards the environment. To simplify the connection of these insulated metal hoses to the extraction and filter unit as well as the recirculation unit, quick-release systems such as bayonet fittings, fire service couplings, camlock couplings, or similar connections can advantageously be used.

[0026] To overcome the differential pressure required for operation, especially within the filter unit, and particularly when using depth filters, a fan is employed, preferably a radial fan. The fan is preferably located within the filter unit housing. The filter unit housing preferably consists of sandwich panels, in which, for example, a core of thermally insulating mineral wool approximately 30 to 50 millimeters thick is enclosed by galvanized sheet steel. This design is mechanically stable, weatherproof, and advantageously prevents condensation caused by excessive cooling of the flue gas.The fan can optionally be used to assist with starting the fire: if, for example, it is activated at a higher speed for a certain period of time via a wireless switch before lighting the fire, the negative pressure in the chimney can be built up in such a way that no bothersome smoke escapes from the stove when it is started. This can be particularly helpful with short chimney lengths and in warm weather conditions to prevent smoke from entering the living space. At the same time, sufficient negative pressure in the flue ensures that enough oxygen is supplied to the fuel from the start of combustion, thus improving the combustion process and counteracting the formation of particulate matter from the outset.

[0027] The solutions according to the invention are primarily intended for use in accordance with the legal requirements of the First Federal Immission Control Ordinance (1. BImSchV) for the separation of particulate matter from the exhaust gas of small solid-fuel combustion plants. The text of the 1. BImSchV refers to particulate matter as the target quantity to be separated. However, practical testing has surprisingly revealed that large quantities of condensate components such as tars are also separated along with the particulate matter, and these can far exceed the actual amount of particulate matter.

[0028] According to a preferred embodiment of one of the aforementioned designs with at least two spatially separated assemblies, the free flow cross-section of the first connecting unit (38) and / or the second connecting unit (48) is smaller than the free flow cross-section of the connecting pipe of the extraction unit to the flue gas path. By using these smaller cross-sections, the connecting elements can be designed to be significantly more material- and space-saving and easier to install. For example, the diameter of the connecting pipe in many chimneys is typically between 130 mm and 150 mm. The inner diameters of the connecting elements can advantageously be DN 100, DN 80, DN 65, DN 50, or even smaller. The advantages in terms of material usage and handling are particularly evident with a double pipe run and an additional insulating layer in each case.

[0029] Advantageously, the extraction opening is also provided for along a pipe circumference of the extraction unit and / or the recirculation opening is located along a pipe circumference of the recirculation unit. This has the advantage that the largest possible quantity of flue gas to be cleaned can be supplied to the filter unit and, after cleaning, returned to the recirculation unit.

[0030] Preferably, as in Fig. 33As shown, a temperature sensor (T1) is provided in the lower part of the extraction opening or below the extraction unit (30), which is advantageously configured to activate the fan when a predefined flue gas temperature or a typical temperature gradient is exceeded. This prevents unnecessary fan operation. Control via the temperature gradient has the advantage that a fixed temperature value for starting the fan should be chosen high enough so that it is not accidentally reached in the height of summer under strong sunlight. However, this high value poses the problem in winter that the fan is switched on relatively late and a relatively large amount of flue gas is released unfiltered into the atmosphere. Another embodiment, such as...A combination of a fixed temperature value with adjustment based on the ambient temperature or a time function that allows for summer and winter operation is possible. Alternatively, a combination of at least two of the listed start conditions—temperature threshold, time point, and temperature gradient—can be used for both the start and stop functions.

[0031] If the flue gas exceeds the maximum permissible operating temperature, particularly for the filter elements, the fan can advantageously be switched off or throttled to effectively prevent impermissible overheating of the filter unit, even in combination with other cooling measures. In this case, the flue gas can be temporarily discharged unfiltered, either completely or partially, into the atmosphere.

[0032] The normal flue gas temperature in existing masonry chimneys, with some variation, is often around 100°C. In insulated metallic double-pipe designs, the flue gas temperatures are higher due to the lower heat loss. A filter material class used according to the invention has permissible operating temperatures in the range of 100 to 200°C. The limitation of the operating temperature can, as with synthetic fiber filters, result from the filter material itself, or, in the case of artificial mineral fibers such as glass wool, be due to the binders.

[0033] To illustrate this, consider the following example: In a masonry chimney, the maximum flue gas temperature during a normal wood burn at the end of the flue gas path is 120°C. The most temperature-sensitive component in this example is the filter medium of the filter element (50). A plastic fabric is used as the filter medium, which the manufacturer has approved for temperatures up to 180°C. For safety reasons, this filter material should only be operated at temperatures of up to 160°C. In this case, the maximum operating temperature (of the filter medium) is 160°C. Therefore, flue gas temperatures in the immediate vicinity of the filter medium exceeding 160°C are considered excessive temperatures with respect to the filter medium.

[0034] The flue gas from the combustion process is cooled on its way to first contact with the filter medium, for example, by heat losses through the walls of the particulate matter separator, by the introduction of ambient air, and / or by partially cooled, recirculated, cleaned exhaust gas. Only when the flue gas temperature exceeds 160°C at this first contact with the filter medium are there any flue gas temperature exceeding this limit in this example. Therefore, the concept of flue gas temperature exceeding this limit is specific to each individual case and cannot generally be defined as a fixed value applicable to a wide range of applications.

[0035] A characteristic of the presence of excessive temperatures in the flue gas is that the fine dust separation device should detect these, preferably at an early stage, in order to counteract them by suitable cooling measures in order to prevent thermal damage to parts of the device (in this example, the filter medium).

[0036] If these flue gas temperature spikes are mild and short-lived (brief and minor temperature peaks), the particulate filter may be able to maintain filtration by providing additional cooling of the flue gas, for example, by opening secondary air dampers or increasing the fan speed to draw in more secondary air. The particulate filter's control system can react even before the flue gas temperature near the filter exceeds 160°C to initiate cooling in a timely manner, for example, via a pre-alarm threshold of 150°C or by analyzing the flue gas temperature gradient, which detects rapid increases during temperature spikes. These short-term temperature spikes can occur, for example, when the stove door is opened to add wood, especially if the stove was previously operated with a reduced air supply.In this case, the fire may flare up briefly, resulting in a temporary temperature spike in the flue gas.

[0037] Overheating of the flue gas can also occur over a longer period and be more pronounced. This can happen, for example, if there are malfunctions in normal operation, such as a leaking or improperly closing furnace door, or if the door is not closed correctly – either due to operator error or because the door is blocked, for example, by the protruding ash drawer in a room overflowing with ash. In these cases, a larger quantity of combustion air enters the furnace chamber over a longer period, so the flue gas temperature tends to be elevated for a longer duration and with a greater amplitude. The resulting overheating of the flue gas is generally more difficult for the particulate filter to compensate for through additional cooling measures of the flue gas (e.g., introducing false air via dampers or increasing fan speed).

[0038] As an alternative to the fine dust separator's reaction to high flue gas temperatures, all components can be designed to withstand these high temperatures. Even though the flue gas temperature here may be the same as in the previously described overtemperatures, the term "overtemperature" is not used here, as the temperature-resistant design of the components prevents thermal damage. Examples of temperature-resistant designs include high-temperature stainless steel depth filters, which allow operating temperatures of approximately 1,000°C, or the arrangement of fans outside the flue gas stream, which generate the pressure differential via the injector principle (similar to jet-pulse filters, cf. Bernoulli's principle, without separate illustration). Temperatures of approximately 1,000°C can occur locally at the filter medium, for example, during the combustion of the captured fine dust.Therefore, according to the invention, fans can also be used for operating temperatures lower than 1,000 °C, since the fan, with a suitable arrangement, is not exposed to these high temperatures and can be additionally cooled, for example, with false air.

[0039] Given that the special operating conditions of high temperatures (or overtemperatures) occur relatively rarely, if only for reasons of energy efficiency of the combustion systems, the temperature-resistant design of as many components as possible appears to be the technically safest, but also the most expensive, solution.

[0040] In addition to the aforementioned overtemperatures, the device according to the invention should also be designed in such a way that, in the event of a maximum operational malfunction such as a chimney fire, also called a soot fire, in which temperatures of about 1,000°C are to be expected, it is not thermally destroyed itself and does not lead to the spread of hazards, such as dripping burning plastic.

[0041] Both the thermocouples and the steel of the connecting piece and bypass path generally withstand operating temperatures of approximately 1,000°C. In this extreme case, the fan is switched off, preventing hot flue gas from entering the filter unit. In the design with two separate assemblies, the spatial distance between the extraction unit and the filter unit, as well as the near-zero heat conduction via the connecting elements (38, 48), provide further thermal protection for the filter unit 60 and, in particular, the filter element (50).

[0042] Temperature measurements are preferably taken using thermocouples, but other methods such as temperature sensors, bimetallic switches, thermal switches, infrared measurements, infrared cameras, fusible links, etc., are also possible and are part of this invention, even if they are not explicitly mentioned. For the sake of simplicity, the terms thermocouple and temperature sensor are considered interchangeable here, as are the terms fan and ventilator.

[0043] When implemented in an assembly for extraction and filter unit, a thermal separation (22, Fig. 34 ) present, which preferably consists at least predominantly of artificial mineral fibers and particularly preferably of rock wool.

[0044] In the device according to the invention, a thermal protection mechanism comes into effect when the overtemperature criterion is met, i.e., when the maximum permissible gas temperature, in particular in the area of ​​the filter elements, has been exceeded, or a pre-warning level of the maximum permissible temperature has been exceeded, or one of the aforementioned exceedances is indicated due to the temperature gradient.

[0045] In the embodiment of the invention with at least two spatially separated assemblies for the extraction unit and the filter unit, which are fluidically connected or connectable to one another by means of connecting units or means (38, 48), the simplest protective measure is to switch off the fan. It is also possible for the fan to reduce its speed so that the gas-side heat input into the filter unit, in conjunction with other measures mentioned below for the embodiment with a single assembly, and the cooling via the surfaces of the housing and the connecting elements, is reduced to such an extent that filter operation with reduced intake can be maintained without exceeding the permissible maximum temperature, at least for an extended period.

[0046] In the embodiment of the invention with a common assembly for the extraction unit and the filter unit, a thermal separation (22) between the filter unit and the bypass path is advantageously provided. This thermal separation preferably consists mainly of artificial mineral fibers and more preferably at least predominantly of rock wool.

[0047] The following additional thermal protection measures are independent of the fan speed and are to be understood as examples only, not as limiting to the invention. Other measures with a comparable cooling effect, not explicitly mentioned below, also fall under the category of thermal protection measures.

[0048] Throttlement of the gas path, preferably in the extraction path between the extraction element and the filter element: Here, throttling refers to reversible as well as irreversible means of influencing the flow resistance through the filter element, e.g. flaps, closure with swelling material (two-component, polyurethane) for example triggered by a fusible link, etc.

[0049] A restriction, for example in the area downstream of the fan, also has a protective effect on the filter elements, since with obstructed gas discharge, less or no gas can flow into the filter unit, thus reducing or preventing the heat input into the filter element. Separating the connecting element(s) (38, 48) is also considered a restriction of the gas path in this context.

[0050] Cooling by introducing false air, preferably in the direction of flow in front of the filter elements (50), through additional opening(s) and / or additional fan(s).

[0051] Cooling by coolant, preferably water quench, preferably in the direction of flow upstream of the filter elements (50).

[0052] Opening of (emergency) flaps so that the hot flue gases are discharged to the atmosphere directly before contact with the filter material.

[0053] Preferably, a depth filter is provided as the filter element, which is designed to separate fine dust, condensate and / or condensate components. Such a depth filter offers a significantly better ratio of separation efficiency to service life in the particle size range of fine dust from small combustion plants than other filter types, such as surface filters.

[0054] Advantageously, the filter element includes a filter according to filter class G4, M5, M6, F7 to F9 and / or E10 to E12 of DIN EN 779 (2012).

[0055] According to a preferred embodiment, a pre-filter of filter class M5 or M6 and a fine filter of filter class F7 to F9 are provided as filter elements. A separating layer, preferably made of a coarse-pored material, can be provided between the pre-filter and the fine filter, particularly to prevent adhesion at the interface between the filter elements. Such an arrangement achieves multi-stage filtration, resulting in a high degree of flue gas purification. Filter materials not classified in the aforementioned filter classes according to DIN EN 779 (2012) are considered equivalent within the meaning of this invention if they offer comparable separation efficiency. This also applies if other filter materials, such as metal or ceramic filters, are used.Even with other filter class designations or no designations at all, these equivalent filters are considered usable according to the invention. According to the invention, and for use according to the invention, the definition of filter classes according to DIN EN 779 (2012), such as M5, M6, F7 or F8, also applies to other filter materials without an explicit filter class specification according to this standard, provided that these filter materials have a comparable separation efficiency.

[0056] Alternatively, a series connection of a separately arranged pre-filter and a separately arranged fine filter can advantageously be provided as a filter element, wherein the pre-filter and the fine filter are separated by means of at least one partition (70 in Fig. 35 ) are spatially separated from each other. This has the advantage, among others, that it is easier to replace the respective filter.

[0057] A further embodiment of the invention provides that, instead of a series connection of filter materials of different fineness, for example coarse / fine, coarse / medium / fine, or the like, so-called graded filter materials can also be used according to the invention. These filter materials advantageously have areas of varying density. The density of the filter material advantageously increases in the direction of gas flow, so that a series connection, for example coarse / fine or coarse / medium / fine, can be achieved within a single piece of filter material. According to the invention, a graded filter material is therefore to be considered equivalent to a series connection of individual filter materials with individual filter stages.

[0058] Preferably, the filter unit has an additional filter element (78 in Fig. 36) for the start of operation, which is located downstream of the filter element. Particularly when the device is operated with fresh or new fine dust filters, such an additional filter element can achieve reliable cleaning of the flue gas.

[0059] According to a further advantageous embodiment, a silencer (72 in) is also included in the filter unit. Fig. 36) and a switching unit (76) is provided, wherein the switching unit serves and is advantageously configured to direct flue gas over the additional filter element during operation with fresh filters until the pressure drop across the additional filter element reaches a predetermined pressure drop. Alternatively and / or in addition to control via the pressure drop, the switching unit can advantageously also switch after a predetermined operating time so that the additional filter is bypassed. Up to this point of switching, the fresh filter elements (50), in the direction of flow upstream of the additional filter (78), are generally so heavily loaded that they achieve a sufficiently high cleaning effect. The material of the additional filter can advantageously consist of a packing of mineral wool or wool, cotton, or linen.This material is not regenerated and is replaced when the filter elements are changed, and is preferably disposed of thermally. However, according to the invention, it can also be provided that the gas passes through the additional filter element and the silencer in parallel, or through both the additional filter element and the silencer.

[0060] Preferably, the extraction unit (30) has a conical shape that widens downwards. This has the advantage that dust deposits that occur over time can be better avoided.

[0061] According to a further preferred embodiment, the filter unit also includes a desulfurization device, an odor removal device, and a device for removing primarily carcinogenic substances such as PAHs (polycyclic aromatic hydrocarbons), BaP (benzo[a]pyrene), and PCDD / F (dioxins and furans), as well as a carbon monoxide reduction option through combined operation with preheating of the combustion air of the furnace according to DE 10 2014 015 491 A1 (exhaust gas air heat exchanger arrangement). Explicit reference is made to DE 10 2014 015 491 A1 if the descriptions and details provided in this application should be insufficient. Carbon monoxide removal is also possible, for example, by using specially impregnated activated carbons and similar materials, such as those used in respiratory masks.

[0062] Preferably, the filter unit further comprises a shaping element designed to counteract the collapse of filter elements, particularly when the device is operated at low flow rates. Such a shaping element can be located inside filter bags or, for example, as a metallic separating layer between a pre-filter and a fine filter. Since this prevents the filter elements from collapsing, the effective filter area and thus the service life are advantageously increased. Furthermore, the maintenance requirements of the device are significantly reduced.

[0063] A shaping element advantageously has the form of a cylinder or truncated cone on the outside and, in its position inserted into the filter pocket, allows flow in the direction of the axis of the filter pocket, so that no areas of the filter element are cut off.

[0064] The forming element should be stable enough to keep the filter bags open and as lightweight as possible to prevent them from sagging. Further desirable properties of the forming elements include affordability, ease of procurement, and sufficient temperature resistance. The use of plastic-free paper cups, especially those with a hole in the bottom for improved flow, has proven to be a practical and cost-effective solution. These cups are lighter, more readily available, and less expensive than process-engineered filter media made of temperature-resistant plastics, such as those used in PVDF. In this context, "paper cups" also refers to other shapes made primarily of cardboard that have the same or a similar effect on the shape of the filter elements.

[0065] A particular feature of the embodiments with at least two assemblies of the present invention is the structural separation of the part located in the axis of the flue gas flow, consisting of the extraction unit and recirculation unit, and the filter unit. This design according to the invention advantageously eliminates the need for a separately constructed bypass chamber, which is required for safety reasons for the unfiltered discharge of flue gases to the atmosphere and which is necessary in other particulate matter filter concepts.

[0066] This design according to the invention advantageously ensures safe and robust operation without the need for failure-prone flue gas dampers or other throttling devices. Due to the structural separation of the filter unit, significantly larger filter areas can be used than, for example, in fine dust filter designs in a single assembly that are mounted directly on the chimney.

[0067] Another embodiment of the invention has throttling or shut-off devices for air or gas, such as flue gas dampers.

[0068] One embodiment of the invention has at least one flue gas damper 24 for directing the gas flows within the device, as disclosed, for example, in DE 10 2015 103 337 (item 6) and DE 34 44 437 (items 9 and 9'). Fig. 34 The flue gas damper 24 is shown as an example. In this design, it can advantageously be used to throttle or shut off the core area of ​​the bypass between the intake and recirculation openings.

[0069] In the assembly configuration, the components extraction unit, optional recirculation unit, and filter unit are arranged in a common assembly or housing, advantageously including a thermal break (22) between the bypass path (20) and the filter unit (60) or filter element (50), which preferably consists of artificial mineral fibers and particularly preferably of rock wool, and which protects the temperature-critical components, such as the filter element, from damage in the event of flue gas overheating (exemplary illustration in Fig. 34 ).

[0070] In a construction according to the invention with an assembly for mounting on the top edge of the chimney, the design inherently limits the assembly's dimensions, preventing it from significantly exceeding the chimney's size and restricting its height. This limitation is due to static considerations, such as wind load, and / or aesthetic reasons, as a fine dust separator mounted on top of a chimney and protruding considerably above it would be perceived as obtrusive. With an average chimney cross-section of 50 cm x 50 cm, the geometry and dimensions of such a fine dust filter construction (50 cm x 50 cm x 50 cm) make it virtually impossible to accommodate a filter area of ​​more than one square meter with a filter approximately 20 mm deep, especially when deducting the space required for the bypass path (20) and the side chamber containing the fan, control unit, etc.The small filter area can result in a significant reduction in service life if the filter cannot be effectively regenerated or cleaned.

[0071] Utilizing the space below the top of the chimney allows for a significantly larger version of the invention. This enables a considerably larger installed filter area, thereby reducing the airflow velocity to such an extent that the dust settles in a loose dust cake, making cleaning possible.

[0072] In contrast, the inventive design with two assemblies does not have a comparable limitation of the filter area, so that a significantly longer service life can be achieved simply by increasing the filter area, without needing to be cleaned.

[0073] In the event of operational disruptions, such as power outages or lack of maintenance of the filter elements, in this solution according to the invention with two assemblies, the flue gas follows the path extending the axis of the original flue gas path without a particulate filter, for example the chimney - in the variant with one assembly, this occurs via the internal bypass path (20, Fig. 34 ).

[0074] Advantageously, according to the invention, the flue gas is only deflected from the axis of the original flue gas path and directed to the filter unit by the negative pressure prevailing in the extraction unit during intended operation.

[0075] In many houses, the chimney, and therefore a common installation location for the separator, is situated in inaccessible areas on the roof, creating an increased risk of falls during access. This risk can be reduced to near zero, and preferably eliminated, by employing trained professionals using appropriate safety harnesses, etc.

[0076] In the solution according to the invention, the components should be serviced exclusively by trained specialists with appropriate safety precautions, especially in cases of poor accessibility, steep roofs, etc.

[0077] The filter unit (60) of the solution according to the invention is a comparatively simple component. If the filter unit according to the invention is installed on an easily accessible flat roof, the replacement of the filter elements could therefore also be carried out by laypersons. Even on pitched roofs, there are components such as steps for chimney sweeps and railing inserts for retrofitting balconies, for example, so that, at least theoretically, access by laypersons is possible without risk. Under favorable circumstances, the filter unit according to the invention can therefore also be maintained by skilled laypersons with special safety precautions. However, it is preferable that the replacement of the filter elements according to the invention be carried out by specialist companies or qualified personnel.

[0078] Terms specific to this invention are defined below: "operationally necessary enclosure volume"The device according to the invention describes the part that is indispensable from a technical point of view and distinguishes it from the part of the structural design of the invention that is not necessarily required from a technical point of view, such as optical decorative elements.

[0079] The required operating volume of the housing includes the filter chamber with filter elements, the extraction section, any recirculation section, a volume for collecting the separated and cleaned fine dust, the fan and control unit, and their weatherproof housings, including any insulation installed therein. It also includes the volume of connecting elements (including external connecting elements in multi-unit configurations, for example, if the extraction section located at the chimney is spatially separated from the filter chamber and a connecting element such as a flexible hose or a rigid pipe is installed for supplying flue gas from the extraction section to the filter chamber). The same applies analogously to connecting elements for recirculating the cleaned flue gas. Any insulation of the connecting elements is also included in the required operating volume of the housing.

[0080] If silencers and / or start-up filters are installed, these, along with their weatherproof housings, are also included in the required operating volume of the device according to the invention, as are other components and connecting elements required from a technical perspective. The control unit with optional transmitting and receiving devices is also included in the required operating volume. This also applies if the control unit has additional functions such as WLAN, which can also be used for purposes other than fine dust separation, provided that the volume of the hardware components for these additional functions does not exceed five liters.

[0081] The required volume of the housing does not include spaces within a casing of the device according to the invention that do not serve the primary purpose of the device according to the invention, including sound insulation, such as an optical decorative casing of the device, which may also form cavities that are not required for the primary technical purpose of the device, i.e., dust separation.

[0082] The designations "Chimney opening" or "Top edge of the chimney or flue" describe the upper end of the chimney without the device according to the invention ( Fig. 1 , shown here as an example in a brick-built design). Even though the device according to the invention is mounted here, and the exit of the (cleaned) exhaust gas is thereby spatially elevated, the aforementioned designations still refer to the opening or upper edge of the originally existing chimney before the device was mounted.

[0083] The information "below the chimney opening" This describes the space at the mouth or top edge of the chimney that originally existed before the device could be installed. Fig. 1 This is the space all around the brick chimney.

[0084] The term "operationally necessary housing volume below the chimney outlet" encompasses, for example, the installation space of the filter chamber, fan, and control system, which are required when the device is mounted in Fig. 1 The chimney opening is located below the original chimney flue, i.e., within the area of ​​the brick chimney. If, for example, a decorative cladding is installed along with the device, its installation space is not included in the required operating volume of the housing.

[0085] For quick and easy cladding of chimneys, so-called " "Changing heads"or slip-on chimney caps are common. In this method, a prefabricated chimney cladding, for example made of metal or fiber cement, is placed over a chimney protruding from the roof and then attached to the chimney. Fig. 23 This shows an example of how a classic slip-on chimney cap (180) is fitted over a chimney (100) for chimney cladding. Prefabrication of the slip-on chimney cap minimizes on-site assembly time and thus reduces project costs. Further information on slip-on chimney caps can be found, for example, on the websites www.ruckzuck-schornsteinverkleidung.de or www.ahrens.at / produkte / neubaukaminsysteme / stuelpkoepfe (accessed: November 2022) as well as in relevant technical literature.

[0086] A particularly preferred embodiment of the invention consists in the chimney filter being designed as a slip-on head, i.e. preferably in one piece, so that it can be quickly and easily lifted onto the chimney in one piece using a crane, a mobile work platform or the like, and only needs to be connected there to a previously mounted base plate, preferably by means of screws.

[0087] The installation via a base plate (496) is preferably carried out by a specialist company, which drills vertical holes into the top of the chimney and glues threaded bolts (498) or similar fastening units in place with a special adhesive suitable for this purpose.

[0088] In contrast, assembling individual components is significantly more complex and, in practice, will only be done for cost reasons if the distance between the chimney and the possible location for a crane, etc., is too great.

[0089] The most preferred optical design of the invention includes the possibility of designing the invention, despite its size, in such a way that it is barely noticeable when mounted on the roof and ideally only upon very close inspection.

[0090] For this purpose, a technique known primarily from the field of automotive color design can be used: vehicle wrapping. Vehicle wrapping is a widespread alternative to painting vehicles. The films are lightfast and UV-resistant.

[0091] These films can be solid colors, patterned in any way, and can also be digitally printed. Digital printing allows for large-format digital photos to be printed directly onto the films.

[0092] With regard to the invention, it is therefore possible to digitally photograph the chimney before mounting the filter, to print its surface appearance onto a film and to glue it onto the outer surfaces of the chimney filter, in both slip-on and modular designs.

[0093] For example, if a chimney is built of brick or clad in slate, it is photographed before the filter is installed and the images are used for digital printing of the films. These films are then preferably applied to the outer surfaces of the chimney filter before installation, ideally at the manufacturer's premises shortly before shipping.

[0094] After the installation of the foil-covered chimney filter, the chimney appears in the same condition as before installation, for example, when a brick or slate look is transferred using foil and digital printing.

[0095] The size of the chimney increases by approximately half a meter with the installation of the invention, due in part to the technical housing (XY) and the width by about 15 cm for the two filter chambers (XY) when a design as shown in Fig. 55 is being implemented.

[0096] In an exemplary embodiment of the invention as a slip-on head, the inner part (182, Fig. 24 ) similar to a classic slip-on head cover (180, Fig. 23 ), however, preferably without visually appealing features for cost reasons. This inner part of the slip-on filter (182) primarily serves to connect the slip-on filter to the chimney. The filter chamber(s) (184) of the invention are grouped into Fig. 24For example, the inner part (182), as well as the housing for peripheral equipment (186), which preferably houses the control unit and the fan, and optionally a silencer and an additional filter (78), are shown. An outer casing (188) advantageously encloses the arrangement consisting of filter chamber(s) (184), housing for peripheral equipment (186), and extraction and recirculation section (120). Possible insulation of the filter chambers or the outer casing is not shown separately here for the sake of clarity.

[0097] An important technical feature of the device according to the invention is its " "Soot fire safety".Since it cannot be completely ruled out in practice that deposited soot might ignite or smolder due to sparks or spontaneous combustion, it must be ensured that no further damage occurs even in such a case. Essentially, the aim is to prevent any harmful effects on the surrounding area should a soot (smoldering) fire occur within a component, in this case the chimney filter. For example, it should be prevented that parts in the vicinity of the component are damaged or ignited by heat radiation. It should also be prevented that, for example, burning plastic drips from the component and thus causes further fires.During the design phase, care must be taken to ensure that no components that could promote fire spread, such as plastics, are introduced into the areas of the extraction and recirculation unit that are exposed to particularly high temperatures. The filter media can consist of plastic fibers, but these are preferably installed within a temperature-resistant housing made of two long steel sheets and a layer of rock wool.

[0098] When soot (smoldering) fires occur, temperatures of up to 1,000°C are to be expected. For the device according to the invention to be soot fire resistant, the housing of the device should withstand a temperature of 1,000°C for the duration of a typical soot fire without mechanical failure. This can be expected with a galvanized sandwich sheet construction insulated with mineral wool. To effectively limit heat radiation to the surroundings of the device, ventilated panels (190, Fig. 27 ) are used, which can advantageously also be made in multiple layers. The direct propagation of radiant heat is hindered by such a panel, and the transfer of radiant heat after this panel has heated up is further reduced by the air cooling of this panel. If several ventilated panels are used, as in Fig. 27 This effect is significantly enhanced when the elements shown are present on the right-hand side.

[0099] Alternatively or additionally to the ventilated panel, the spread of heat (radiation) in a soot fire can also be limited by insulating materials (192), as shown in Fig. 27 is illustrated.

[0100] Another alternative for achieving or at least increasing soot fire safety can be achieved through proactive measures. The aim here is to detect and extinguish a soot (smoldering) fire as early as possible. Locally occurring smoldering fires in a larger volume, such as the filter chamber, cannot be reliably detected with temperature sensors, especially since the temperature of the filter chamber varies considerably between standstill and operation.

[0101] Carbon monoxide (CO) is produced during smoldering fires and can be detected by suitable sensors. Detection is made more difficult by the fact that CO is introduced into the flue gas during normal operation, even without a smoldering fire. If a sudden increase in CO concentration is measured after the device has been idle for an extended period, a smoldering fire can be assumed. If at least one CO sensor is installed before and after the filter chamber, a CO concentration increase caused by a smoldering fire can also be detected during operation. Ideally, one CO sensor is located at the flue gas inlet to the device and another at the flue gas outlet. This allows for the detection of smoldering fires that occur, for example, within a silencer, fan, or connecting pipes.

[0102] Once a soot (smoldering) fire is detected, it can be extinguished, for example, by introducing water. Advantageously, this water contains antifreeze to prevent it from freezing during winter operation. EP 20 213 371.6 describes the introduction of a wetting agent into a chimney filter, which serves to compact the surface of the cleaned soot and fine dust. Such a wetting device (introduction of a wetting agent) can also be used to extinguish a developing soot fire. If a soot smoldering fire can be extinguished in its incipient stage, the temperatures are significantly lower, so the requirements for shielding against heat radiation from the surroundings of the device can be considerably reduced.

[0103] One precaution against the escape of molten plastic, which can occur at significant overtemperatures in the area of ​​the filter elements, is exemplified by the labyrinthine fastening of the housing walls in Fig. 43 depicted.

[0104] Another unexpected effect can be observed in connection with soot fires. It has surprisingly been found that loose, fluffy soot, i.e., separated and agglomerated fine dust with organic components originating, for example, from condensed hydrocarbon aerosols, is particularly prone to spontaneous combustion, especially immediately after cleaning and even when cold. Ignitability due to sparks is also particularly pronounced in this loose, fluffy state. This effect is not described in the safety data sheets for commercially available soot, i.e., the numerous soot derivatives used, among other things, as additives in the rubber industry. The effect of spontaneous combustion:

[0105] The soot doesn't burn with an open flame like wood, but instead smolders in a way that is invisible from the outside and is characterized by internal embers. Because the soot layer acts as a strong thermal insulator, this smoldering fire is virtually undetectable by external temperature measurements. However, monitoring carbon monoxide is a good method for detecting a smoldering soot fire, as a large amount of carbon monoxide is produced due to the relatively low temperatures and poor oxygen supply within the soot volume.

[0106] Assuming that only half the carbon is converted to carbon monoxide during a smoldering or burning fire, even half the average soot production (0.75 kg of soot = 50%, or 1.5 kg of soot per year and wood-burning stove) per firing results in a carbon monoxide level that is lethal to humans within one hour in an 85-square-meter room. In a room twice the size, the concentration is half as high, and therefore a two-hour stay in such a room would be fatal.

[0107] The following data sources and calculations can be used to estimate the potential danger of carbon monoxide emissions: German Federal Environment Agency: ~17,000 t of particulate matter from wood-burning stoves in Germany, 11 million stoves: 17,000,000 kg / 11 million = 1.5 kg of particulate matter per wood-burning stove per year, lethal concentration (LC 60 min, CO, human): 1,500 ppm - 1,750 mg / m³ at 20°C, 50% of 1.5 kg of soot → 0.75 kg of soot, of which 50% is converted to CO → 375 g C to CO → 875 g CO → 375,000 mg CO / 1,750 mg / m³ (LC 60 min) → 214 m³ air volume → 85 m² room with a 2.5 m ceiling height.

[0108] This means that a normal living space of about 85 square meters in size is already so heavily polluted with carbon monoxide by half the average amount of fine dust per combustion due to a smoldering or burning fire that the lethal dose for humans is reached after one hour.

[0109] It has also been surprisingly found that preventive hydraulic compaction can significantly reduce the tendency for fire and spontaneous combustion, even to almost zero. Hydraulic compaction, preferably performed directly after cleaning, involves spraying the soot—preferably with water enriched with additives for antifreeze (e.g., sticky substances such as sugar or glycol-based antifreeze) and for homogenizing and clumping the soot—to destroy or at least reduce its fluffy structure.

[0110] To further reduce the potential hazards during storage, particularly of soot loosened by cleaning, it is advisable to monitor the carbon monoxide content at least periodically, for example, once an hour in the air. Care must be taken to ensure that no flue gas from the combustion process, which also contains carbon monoxide, influences the measurement, which should be taken during extended periods of inactivity of the filter according to the invention. If, for example, measurements are taken at hourly intervals and an elevated value is detected, it may be useful to repeat the measurements at shorter intervals, for example, every five minutes. In particular, if a continuous increase in the carbon monoxide concentration is measured, the presence of a smoldering or burning fire is likely. In this case, a warning should be issued to people in the vicinity and also to qualified personnel such as the chimney sweep.

[0111] The wetting device enables the filter according to the invention to independently initiate initial fire containment or suppression. However, timely monitoring by qualified personnel is also advisable.

[0112] Even in fine dust separator configurations other than the filter according to the invention with integrated wetting device, the detection of carbon monoxide and an automatically initiated first extinguishing attempt can be useful.

[0113] Especially if the smoldering fire takes place in a location where there is even a slight air current, the risk of carbon monoxide formation is not insignificant.

[0114] Under normal operating conditions, the chimney draws air from the stove upwards to the flue outlet. However, there are instances, particularly in summer with hot, humid air, when the smell of the fireplace becomes clearly noticeable in the room where the stove is located. In these cases, the chimney draft reverses. If a smoldering fire then develops on the chimney walls above the stove, caused by a spark or spontaneous combustion, the fire is supplied with air via the draft, and the carbon monoxide is carried towards the stove.

[0115] Another instance of flow reversal in the chimney can occur due to missing, faulty, or improperly installed controls for extractor hoods in living spaces or in the case of controlled residential ventilation during malfunctioning operation.

[0116] For example, if the masonry of an older fireplace becomes leaky, carbon monoxide can also enter adjacent rooms where no stove is located. The risk of carbon monoxide ingress increases significantly, especially if range hoods or similar appliances are operated in these rooms.

[0117] Soot deposits in the lower part of the chimney, near the cleanout door for the chimney sweep, are usually not permeated by airflow. In the case of leaks in the chimney masonry, a faulty seal on the cleanout opening, and especially with ventilation systems and kitchen extractor hoods, the risk of carbon monoxide poisoning from smoldering or burning fires increases here as well.

[0118] A further optional addition to the invention includes a method and a device for lighting design of buildings, installed in particular on roofs of buildings, in which the light from a light source is projected onto an aerosol cloud.

[0119] The light sources (390) used here include preferably colored lamps and lasers, as well as holographic projectors for static images (392) and those for film sequences. An aerosol cloud (394) is understood to be one that is not in a solid state, such as a projection screen, and can consist of water vapor and exhaust vapor plumes, including possible dust particles and condensing hydrocarbon-containing components, as well as artificial fog or a combination of exhaust gas, water vapor, and / or artificial fog. Artificial fog is understood to be an aerosol used, for example, in theatrical and cultural performances, for the production of which commercially available fog machines are used to vaporize a fog fluid containing, for example, glycerin. The use of smoke cartridges, etc., which produce solid-containing, sometimes colored smoke, is also considered, according to the invention, to be an aerosol cloud that serves as a projection surface or...The projection space of a light source can be used.

[0120] The device according to the invention is preferably installed at a flue gas outlet of a building such as a chimney (100) or in its immediate vicinity.

[0121] The device according to the invention is particularly preferably installed in combination with a flue gas cleaning device (396) associated with the chimney, in particular with a fine dust separation device specifically for small biomass combustion plants.

[0122] One advantage of the combined installation is that electrical connections are not normally available on building roofs. By installing a fine dust separator, which can be designed as an electrostatic precipitator or a filtering separator and which, by design, must be connected to a power source, this power supply can also be used for the projection according to the invention and, if necessary, also for the generation of artificial fog.

[0123] Another advantage is that the installation of a particulate matter separator, which is often perceived by homeowners or furnace operators as a legally mandated requirement, adds a positive extra benefit in the form of architectural lighting and / or color design to the building. Such lighting and color designs are familiar, for example, from event venues that use lasers, as well as from the conversion of old industrial sites into recreational areas, such as the Landschaftspark Nord in Duisburg.

[0124] When operating stoves and domestic heating systems, a cloud of condensing water vapor is often visible at the chimney, especially during the colder months. According to the invention, this cloud can be used as a projection surface or projection area for white and colored light emitted by spotlights. A further embodiment of the invention uses holographic projectors as a light source, capable of generating both static and moving images. The normally overlooked or even considered bothersome plume of exhaust thus gains an aesthetic enhancement, as does the chimney itself.

[0125] Advantageously, the device according to the invention has a device for measuring wind direction and / or wind speed (398) and / or a device for changing the position and / or angle of the light outlet, so that under different wind conditions the light outlet can be aligned in such a way that it can follow the aerosol cloud, preferably automatically.

[0126] For better understanding and also to distinguish it from colloquial formulations, a definition of terms follows: The terms used here refer to... Chimney or chimney The term "chimney" refers to an exhaust system according to EN1443. It does not, under any circumstances, refer to a fireplace for solid fuels.

[0127] Peltier elements or Peltier generatorsThey generate an electrical voltage when exposed to a temperature difference. For further details, please refer to specialist literature or, for example, Wikipedia and the keyword "Seebeck effect".

[0128] Under Thermo-photovoltaics Thermal power generation (TPV) is a process that uses infrared thermal radiation to directly generate electricity. This is analogous to photovoltaic cells used in solar technology, which operate without additional mechanical components and utilize the visible part of (sun)light, while TPV converts the infrared portion of radiation into electricity. For further details, see, for example, the MIT publications on the development of TPV.

[0129] The term "modular construction"The term "device" is understood to mean that the device, preferably for assembly, can be brought onto the roof and assembled there not as a complete unit but as several individual lines (models).

[0130] The device can be divided into the following individual parts, for example: filter chamber(s), insulating and weatherproofing cover, decorative cover, mounting on the chimney, connection part, filter part(s), technical part (fan, control, optional silencer, optional start-up filter).

[0131] This is advantageous, for example, if the device needs to be brought onto the roof through a narrow skylight.

[0132] With the designation "Low voltage"This refers to electricity with a lower voltage than that typically used in the 220-volt AC mains supply during normal operation. Operating the device on low voltage, especially on the roof, increases safety during installation, operation, and maintenance. This is because the risk of injury in unplanned situations, such as accidentally touching live parts, is significantly reduced, and further hazards like subsequent falls are avoided. Even in the event of damage to the insulation of live parts, the risk of injury is considerably lower at low voltage compared to 220 / 380 volts.

[0133] For example, a 12 volt DC voltage can be used here, which supplies both the motor of the fan and the control unit.

[0134] A low-voltage supply for the device also includes situations where the device is supplied with low voltage from the outside, even if the current within the device is converted to 220 volts alternating current via an inverter, at least for some components such as the fan motor.

[0135] Under a "Energy storage" An accumulator, or battery for short, is understood to be a device that can be supplied with electricity when, for example, a source that is not available at a certain time, such as photovoltaics, is not available.

[0136] Under the "static support function" of the connecting pipe (112, Fig. 3 It is understood that this connecting pipe, by being inserted into the chimney, can assume a supporting function for the device mounted via the connecting plate (110), for example against wind loads acting on the device.

[0137] Under "standardized mechanical design of the connection plate (110)" A design is understood to be one that allows a simple and secure mechanical connection with the housing of the device according to the invention, for example by sliding it into a holding device and subsequently locking it in place, or by simply clicking it into place.

[0138] An example of the arrangement of the extraction unit (30) and filter unit (60) in "a component group", here in a common housing, is in Fig. 34 illustrated, while the extraction unit (30) and the filter unit (60) in Fig. 33 spatially separated from each other as "two assemblies" are executed.

[0139] Further details, features and advantages of the invention are explained in more detail below with reference to the exemplary embodiments shown in the figures of the drawings. These show: Fig. 1 On the left side, a chimney (100) with an open chimney outlet to the atmosphere, without the fine dust filtering device, from which the unpurified raw gas (138) is discharged to the atmosphere. On the right side of Fig. 1A chimney is shown to which the device according to the invention is attached. A portion of the chimney (100) is still visible in the lower part. The extraction and recirculation unit (120) is mounted in the extension of the chimney opening. The uncleaned raw gas (132) coming from the combustion chamber is directed via the intake nozzle towards the filter chamber (150), where it flows from top to bottom through a bag filter (156). From the lower part of the filter chamber, the cleaned flue gas enters the housing for peripheral equipment (160), which contains, among other things, the fan (166) that provides the necessary negative pressure for the flue gas flow. In the upper part of the housing for peripheral equipment (160), the flue gas is returned via the recirculation nozzle and released into the atmosphere as clean gas (136).Optionally, the chimney connection (120) can be provided with a cover (170) which may have insulation to reduce unwanted cooling of the flue gases. Fig. 2 An embodiment of the chimney mounting as a complete unit (102) of the inventive device for filtering fine dust at the chimney (100), consisting of vertical supports (104), which may, for example, be designed as angle profiles, horizontal struts (106) for connecting and stabilizing the vertical supports, and upper struts (108). Preferably, the horizontal struts can be designed as tension bands made of stainless steel, as are also used in the field of traffic control technology, among other things for attaching signs to traffic light and lampposts. Fig.3. An embodiment of the assembly, in which a connection plate (110) is attached to the upper struts (108) of the chimney mounting as a complete unit (102), providing a standardized mechanical connection for the fine dust filtering device according to the invention. For the gas-side connection of the fine dust filtering device, a connecting pipe (112) can be inserted into the upper opening of the chimney (100), creating a standardized connection for the extraction and recirculation piece (120, optionally only the extraction piece). Fig. 4. An embodiment of the extraction and recirculation piece (120, optionally only the extraction piece), shown here as consisting of the components extraction part (122) and optional recirculation part (124), with a lower inlet for uncleaned raw gas (130) coming from the combustion chamber.Figure 5 shows the outlet of extracted, uncleaned raw gas (132) towards the filter chamber (150), which, optionally after passing through at least the filter chamber, is returned as clean gas (134) via the recirculation section (124) and directed towards the atmosphere via the upper outlet for clean gas (136). Figure 5 shows an embodiment of the extraction and recirculation section (120) with four openings for flue gas flow, each offset by 90°. This allows for easy adaptation to structural conditions during installation. In this illustration, one of these openings for gas passage is open (140), while the other three are closed with blanking plates (142). Further variations, such as simply rotating the extraction and recirculation unit relative to each other, are also possible and are part of the invention without explicit detailed illustration and description. Figure 6 shows a top view of the unit. Fig. 5with a view of the recirculation section (124) located above and a view of the upper outlet for clean gas (136), as well as an opening (140) open for gas passage and three openings (142) closed with blind covers, which belong to the recirculation section located above (124) and which cover the openings of the extraction section located below. Fig. 7 An embodiment for mounting the extraction and recirculation section as a complete unit (120) on the connection plate (110) and the connecting pipe (112) thereby concealed. Fig. 3) for the gas-tight connection with the chimney (100) and the mechanical fastening by the fastening unit (102). Fig. 8 Left shows an embodiment of the filter chamber as a complete unit (150) with a housing (151), a nozzle for the raw gas inlet (152) and a nozzle for the clean gas outlet (154) and an inserted pocket filter (156), which is shown here by way of example with three filter pockets. The separation between the upper raw gas space and the lower clean gas space of the filter housing (151) is effected by a top plate (153) which has an opening for receiving the pocket filter. In the right part of Fig. 8The pocket filter is shown by way of example with an additional filter area (158) comprising three filter pockets, which can serve for the fine separation of fine dust. Other embodiments of the (pocket) filter (156) are also part of the invention, even without explicit illustration and detailed description, such as the embodiment as separate filter pockets with separate pre-filter and fine filter, or filters in hose or bag form, etc. Fig. 9 shows an embodiment for the gas-side connection of the extraction and recirculation section as a complete unit (120) with the filter chamber as a complete unit (150), in which the illustration of the filter pockets of the pocket filter (156) has been omitted for the sake of clarity.The raw gas (132) extracted via the extraction section (122) is fed to the filter chamber (150) via the upper raw gas inlet (152), is cleaned as it flows through the pocket filter (156), which is not shown here, and leaves the filter chamber as clean gas (134) via the lower clean gas outlet (154). Fig. 10 shows an embodiment for the gas-side connection of the device according to the invention for filtering fine dust to the chimney, in which the raw gas (132) is fed to the filter chamber (150) via the extraction section (122) and leaves it as clean gas (134) to be fed to the housing for peripheral equipment (160) by the negative pressure generated by the fan (166) via the gas inlet (162) located at the bottom. Optionally, the clean gas can be passed through a silencer (168) and an additional filter for initial operation (78, .) which is not shown here. Fig. 36) are directed to exit the peripheral equipment housing via the outlet nozzle (164) located here above and be discharged to the atmosphere via the recirculation section (124). Fig. 11 An embodiment of the assembly of the filter chamber (150) and the peripheral equipment housing (160) without showing the connection to the chimney (100). Fig. 12 Top view of Fig. 11 , with a top view of the chimney (100) and the extraction and recirculation section (120), the filter chamber (150), and the housing for peripheral equipment (160). The raw gas flow is represented by the dark arrow and the clean gas flow by the light arrows. Fig. 13 An embodiment analogous to Fig. 11, however, with two filter chambers (150) arranged on both sides of the housing for peripheral equipment (160). By connecting multiple filter chambers, the installed filter area can be increased, thereby also extending the maintenance intervals and / or the amount of flue gas that can be treated. Fig. 14 Top view of Fig. 13 , with filter chambers (150) arranged on both sides of the housing for peripheral equipment (160) and a view from above of the chimney (100) and the upper part of the extraction and recirculation unit (120). The raw gas flow is represented by the dark arrows and the clean gas flow by the light arrows. Fig. 15 An embodiment of the mounting of the filter chamber (150) and the housing for peripheral equipment (160) on a chimney (100). Also shown are the mounting unit (102) and the paths of the flue gas before and after cleaning, as well as the extraction and recirculation unit (120). Fig. 16 A similar embodiment Fig. 15with additional illustration of the cover (170) for the extraction and recirculation unit (120). Fig. 17 An embodiment of the mounting of the chimney filter on the chimney with a semi-transparent illustration of the filter unit (150), housing for peripheral equipment (160) and cover (170) for the extraction and recirculation unit. Fig. 18 An illustration analogous to Fig. 17 , however, with a non-transparent representation of the filter chamber (150) and the housing for peripheral equipment (160). Fig. 19 A representation analogous to Fig. 17 , with an additional illustration of an extra volume (172) which can be filled with operational equipment, for example additional filter area, to better utilize the enclosed space. Fig. 20 A similar illustration Fig. 19 , in the room of the in Fig. 19 The additional volume (172) shown is utilized by an enlarged filter chamber (150), shown here with three large filter pockets (157). Fig. 21 A similar illustration Fig. 20 , in addition to the three large filter pockets (157) and two small filter pockets (157a). Fig. 22 A top view similar to Fig. 21 , in which three large (157) and three small (157a) filter pockets are provided. Fig. 23 The mounting of a classic slip-on top (180) on a chimney (100), which, according to the prior art, is used for quick and easy cladding of the chimney. Fig. 24 A top view of chimney filters in slip-on top design. Shown are the inner part of the slip-on top filter (182), the filter chambers (184) of the slip-on top filter, the housing for peripheral technology of the slip-on top filter (186) and the recirculation part (124). In this view of the embodiment, the chimney is located approximately in the middle of the device. Fig. 25 A representation analogous to Fig. 24with a different arrangement of the filter chambers and filter bags and an outer casing (188) which can be equipped with photovoltaic cells for at least partial power supply of the invention, as well as having a weatherproofing function, for example in the case of a zinc sheet design, or a decorative function, for example in the case of a design in colored aluminum or black glass. Here, the chimney is located approximately centrally with respect to three sides and close to the edge of the fourth side. Fig. 26: An illustration of the chimney filter in a slip-on design with filter chambers (184) arranged on both sides of the housing for peripheral technology (186). Here, the chimney is located in the edge region of the housing volume required for operation. Fig. 27: An illustration of how to make a housing, here by way of example a filter chamber (150), soot fire resistant.Temperature distribution is achieved downwards by a ventilated panel (190), to the right by several, here two, ventilated panels, to the left by an insulating layer (192), for example made of mineral wool, and upwards by a combination of an insulating layer and at least one ventilated panel. Fig. 28 An exemplary representation of a device according to the invention designed as a snap-on filter, in which photovoltaic cells (200) for power generation are attached to the outer casing (188). Fig. 29 A variant of the device shown in Fig. 28. Fig. 28 The invention shown, in which the photovoltaic cells (PV, 200) are not mounted on the outer casing of the device (208), and the current from the PV is directed to the device. Fig. 30 A variant of the invention shown in Fig. 29The invention shown here advantageously utilizes the excess electricity generated by the PV system for another purpose, for example, its conversion to alternating current (204) by an inverter (206), thereby enabling the electricity to be fed into the building's internal or external 220 / 380 V AC power grid, cf. the so-called balcony power plant. Fig. 31 A variant of Fig. 30, which is not part of the invention, since here the PV current is routed exclusively via an inverter (206) and the device (208) is supplied with electrical energy exclusively via a 220 / 380 V AC connection. Fig. 32 On the left, an exemplary arrangement of a Peltier element (210) in the area of ​​the connecting pipe (112), through which the flue gas from the combustion chamber (130) flows. An advantage of this arrangement is that the temperature of the flue gas is at its maximum at this point. Alternatively, this arrangement could, for example, also be housed in the extraction and recirculation section (120). Even without explicit illustration, these and other variants are part of the invention. On the side of the Peltier element facing away from the warm flue gas-carrying side, a cooling element (214) is provided for the Peltier element (212), which preferably also cools against the environment.When operating Peltier elements, a specific maximum temperature must be maintained above which the solder joints begin to melt, for example, at 150 °C, which can lead to the destruction of the Peltier elements. It is therefore advisable to provide overheat protection for the Peltier elements if the relevant flue gas temperatures can exceed this maximum temperature. According to the invention, it is proposed here to provide overheat protection (216) in the form of a space or body between the warm flue gas-facing side and the Peltier element. If the volume of the overheat protection is at least partially filled with a liquid that boils below the permissible maximum temperature of the Peltier element, the temperature in the volume of the overheat protection cannot rise above the boiling point of the liquid.Provided that the vapor rising from the boiling liquid is cooled by condensation, preferably against the environment (218, for example via a vapor-ambient air finned cooler), and fed back into the overheat protection in liquid form, this form of overheat protection is suitable for continuous operation in which the flue gas temperatures frequently exceed the permissible maximum temperature of the Peltier elements. Ideally, this liquid is frost-resistant for use on the roof and is non-toxic and non-flammable. According to the invention, the use of salts, such as a calcium chloride solution, as the liquid for overheat protection is proposed by way of example. At high concentrations of approximately 150 g calcium chloride per 100 g water, the boiling point is in the range of 140 °C and thus safely below the maximum permissible operating temperature of the Peltier elements of 150 °C.Since calcium chloride (CaCl₂ x 2 H₂O) is also used as low-temperature road salt or de-icing salt in winter road maintenance, it is frost-resistant, non-flammable, and non-toxic. If temperatures of, for example, 200 °C prevail in the raw gas (130) for an extended period, the calcium chloride solution boils without its temperature exceeding 140 °C. The rising water vapor condenses upon cooling to the surroundings and is further cooled before being returned to the volume of the overheat protection (216). The salts do not evaporate during the boiling process; they remain in the boiling liquid.Advantageously, a particle and droplet separator (219), preferably in the form of a droplet separator mesh, is located between the overheating protection (216) and the recooling unit (218). This prevents salt particles from the boiling liquid from being carried along with the rising steam and thus causing contamination of the recooling unit (218). When the condensate from the recooling unit is returned to the overheating protection via the particle and droplet separator (219), the particle and droplet separator (219) can be cleaned simultaneously. Fig. 33: An exemplary embodiment in two spatially separated assemblies of the extraction section (30) and filter unit (60) with filter element (50), and a temperature measuring point (T1) arranged here below the extraction section. Fig. 34: An embodiment in which the extraction section (30) and filter unit (60) are arranged in one assembly.Also shown are an optional flue gas damper (24) located above the extraction unit in the area of ​​the bypass path (20), a thermal break (22), and an exemplary configuration of the filter unit (60) with an electrostatic precipitator (50). A detailed description of the extraction and recirculation unit, such as details in [reference], is not provided. Fig. 4For the sake of clarity, the details have been omitted here. Fig. 35: An embodiment with a partition (70) between the pre- and fine separation stages. Fig. 36: An embodiment with an additional filter element (78), silencer (72), and switching unit (76). Fig. 37: An embodiment in two spatially separate assemblies for the extraction unit (30) and the filter unit (60), which are connected to each other via a connecting element for the extraction (38). A recirculation unit (40), which is connected to the filter unit via a connecting element, is also shown. The bypass section (20), through which the flue gas can be discharged past the extraction and recirculation sections to the atmosphere, is also shown. The core section of the bypass path (21) is located in the area between the extraction and recirculation sections.The fan (65) required to generate the necessary negative pressure is preferably located inside the filter unit for weather protection and on the clean gas side of the filters to prevent contamination. In this illustration, the pre-filter (52) and fine filter (56) are shown connected in series. Fig. 38 shows two exemplary designs of heat exchangers that can be connected downstream of the combustion chamber of a furnace to extract thermal energy from the exhaust gas and transfer it to a medium, preferably air. On the left, the heat exchanger is shown in a rectangular version of a shell-and-tube heat exchanger (250). The heat exchanger tubes (258) are preferably supplied with warm flue gas (260) on the inlet side. This flue gas exits the heat exchanger (250) as cooled flue gas (262).The jacket of the heat exchanger can be supplied with varying quantities of preferably cold air via the inlet nozzle (252), which exits as heated air from the outlet nozzle (254). Introducing a large quantity of cold air into the heat exchanger results in greater cooling of the flue gas than a small quantity. The air volume can preferably be changed by controlling the speed of the fan. Ideally, the speed is controlled as a function of the temperature of the exiting flue gas (262), so that a relatively constant outlet temperature of the exiting flue gas (262) can be achieved despite varying flue gas volumes and inlet temperatures. On the right side of . Fig. 38The heat exchanger (268) is shown as an example in a tube-in-tube design. Its operation is analogous to the tube bundle design. Other variants, such as a tube-in-(square) shaft design, are conceivable, as are designs in which the central flue pipe is divided into several smaller pipes. These variants are also part of the invention even without illustration and explicit description, provided they serve the same purpose as described above in item 250. In principle, the combustion air supply to the combustion chamber can also be parallel or concentric to the flue gas path. That is, from the chimney outlet downwards to the combustion chamber or along sections thereof. With this type of combustion air supply in counterflow to the flue gas path, the flue gas system can already function as a heat exchanger, thereby increasing the efficiency of the combustion chamber.The temperature in the combustion chamber must reach a certain value for the combustible gaseous components of the fuel wood, known as wood gas, to be released and combust with the help of supplied oxygen. Cold combustion air must first be heated to combustion chamber temperature using the energy from the fuel. If preheated air is supplied to the combustion chamber, the temperature difference is not as great, and less fuel energy is required to raise the temperature. Less fuel is needed, and the efficiency of the combustion appliance increases. This effect can be further enhanced with a heat exchanger, for example, in the area of ​​the connecting piece, optionally in combination with a particulate filter.In principle, it is possible for the operating unit of the heat exchangers to be operated autonomously with regard to the power supply (fan, temperature control), if for this purpose an arrangement preferably equipped with Peltier elements as in . is preferably used on the warmer inlet side. Fig. 32As described, an overheating protection device (216) with recooling (218) and a particle and droplet separator (219) is advantageously used. An advantageous operating location for the heat exchanger is the transition piece between the combustion chamber and the chimney, particularly when the combustion air is first preheated in counterflow over the exhaust system and then brought to the highest possible temperature in the heat exchanger in the area of ​​the transition piece. Fig. 39: An arrangement of a series connection consisting of a combustion chamber (220), an exhaust gas (air) heat exchanger (222) supplied with ambient air via a fan (224), a fine dust filter (226), and a chimney (228), in which the warm, dust-laden raw gas (236) from the combustion chamber is cooled in the exhaust gas (air) heat exchanger before being cleaned in the fine dust filter and then released to the environment via the chimney.The exhaust gas (air) heat exchanger is supplied with ambient air via a fan and transfers the heated outgoing air to the combustion air intake of the furnace (230) and / or to the environment (232), for example, for heating living spaces. Alternatively, and less preferably, other gases and liquids can also be used as the heat-absorbing medium, also in conjunction with further heat exchangers. In this preferred embodiment, the heat exchanger is arranged upstream of the particulate filter. This has the advantage that the filter materials can be better protected from excessively high temperatures. When supplying the furnace with preheated combustion air, especially when a power- or speed-controlled fan is used, it is essential to ensure that the pressure conditions required for the operation of the furnace are maintained.This can be achieved, for example, by decoupling the transfer of warm air from the heat exchanger to the combustion chamber without pressure, as is done, for instance, in a chimney. The warm air from the heat exchanger is directed into the area from which the combustion chamber draws its combustion air. This transfer area is open to the combustion chamber's installation space, so that neither positive nor negative pressure can build up there. When the combustion chamber is in operation, it draws the warm air from this transfer area. When the combustion chamber is not in operation, it does not draw in any combustion air, and the warm air can be discharged without pressure into the combustion chamber's installation space. Fig. 40: An alternative embodiment analogous to... Fig. 38, in which the exhaust gas (air) heat exchanger (222) is connected downstream of the particulate filter (226). This protects the heat exchanger surfaces from contamination by particulate matter, etc. Fig. 41 Various variants of the integration of the heat exchanger (222), here and preferably in tube bundle construction (250), into the heat supply of a building with an adjacent chimney (100). The white arrows symbolize air, the dark gray ones the raw gas from the combustion chamber, and the light gray ones the flue gas cleaned by the device. In the arrangement in the basement, the air heated in the heat exchanger is selectively directed to the ground floor either as preheated combustion air or for space heating. The cleaned and cooled flue gas is transferred to the chimney. In the ground floor, a variant is shown in which only the combustion chamber is located in the room and which discharges the flue gas into the chimney (100) without cooling and cleaning.The associated unit, consisting of a filter and heat exchanger, is shown here outside the building at ground level and extracts the flue gas from the chimney above the combustion chamber's feed point on the ground floor. The cleaned and cooled flue gas is returned to the chimney, while the heated air is directed into the ground floor room, where it is either used for heating the room or supplied to the combustion chamber as preheated combustion air. By extracting and recirculating the flue gas from the chimney via an extraction and recirculation unit (not shown here), it is ensured that the flue gas is almost completely captured. On the first floor, an arrangement analogous to the one in the basement is shown, with the difference that the warm air generated in the heat exchanger can optionally be supplied to the same room for heating purposes.The second floor shows a variant where the combustion unit is connected to a heat exchanger without a filter. The variant on the third floor shows a combustion unit, similar to the one on the ground floor, which is supplied with warm air from a filter and optional heat exchanger combination located above, in the attic, on the roof, and on or near the chimney. The illustrations shown in the figures, especially those in... Fig. 41 and 42 The figures shown are to be understood as examples and not as limiting. Variants not explicitly shown here are also part of the invention, provided they serve the same or a related purpose. Fig. 42 shows a similar example. Fig. 41Various variants of the integration of the heat exchanger (222), preferably in a pipe-in-pipe design (268) or in a pipe-in-(rectangular) shaft design, into the heat supply of a building with an adjacent chimney (100) are shown. A combustion unit with downstream particulate matter separation is shown in the basement. A combustion unit without downstream particulate matter separation is shown on the ground floor. The heat exchanger (222, 268) is located in the chimney at the level of the room on the ground floor and draws its cold air either from outside the building or preferably from within the building itself, as shown here from the room on the ground floor. It transfers its warm air either to the room on the ground floor, the room in the basement, or to the combustion unit for preheating the combustion air.In this example, fine dust separation from the ground floor combustion system is achieved via a filter located outside the building, downstream of the heat exchanger in the chimney, in the direction of flue gas flow. On the first floor, a similar arrangement to the one in the basement is shown, where the warm air from the downstream heat exchanger, depicted here at the level of the second floor, can be used not only to heat various rooms but also as preheated combustion air. The arrangement on the second floor is similar to that on the ground floor, except that the downstream heat exchanger delivers its warm air at the level of a different floor. In this example, no combustion system is operated on the third floor. These rooms can optionally be supplied with cold air via the heat exchanger located in the chimney and can also be heated via this system.Other installation locations for particulate filters without an integrated heat exchanger are, as shown here, in the attic, on the roof, and on or at the chimney outlet. The illustrations shown in the figures, in particular those in . Fig. 41 and 42The figures shown are exemplary and not to be understood as limiting. Variants not explicitly shown here are also part of the invention, provided they serve the same or a related purpose. Fig. 43 shows an exemplary embodiment for connecting the housing walls (270, 272) which, due to the sealant (274), for which high-temperature silicone can advantageously be used, is gas-tight during normal operation and does not lose its stability even at very high temperatures, such as those that can occur in a soot fire, thanks to the inner and outer fastening plates (276, 278) attached to the housing walls, for example, with steel rivets (280). The escape of plastic from the filter bags, which may melt at excessively high temperatures inside the device (top left), is also significantly hindered or even prevented by the resulting labyrinthine paths from the inside to the outside (bottom right).Figure 44 shows an exemplary building with two chimneys (100) into which the flue gas from combustion plants is introduced, wherein, by way of example, two cleanable fine dust separators according to the invention are installed near the outlet of the right chimney, which can be designed as either a cleanable electrostatic precipitator (300) or a cleanable depth filter (302) and in which the separated and cleaned fine dust is stored in a volume to the side of the axis of the flue gas path and can optionally be removed from this volume via a drain (308), and a cleanable electrostatic precipitator (304) is installed near the outlet of the left chimney, which stores the separated fine dust (310) during cleaning in the axis of the flue gas path, in the part of the chimney below the supply line of the flue gases from the combustion plant, here by way of example in the area of ​​the cleaning opening (312), i.e. the soot bag.The soot (307) adhering to the sides of the flue can be caused both by an electrostatic precipitator (303) installed in the flue gas path and by soot removed from an electrostatic precipitator installed near the flue outlet, which adheres at least partially to the wall due to downward airflow. If the soot (307) deposited on the side walls is affected by a smoldering or glowing fire, the resulting carbon monoxide (CO) emissions can pose a hazard due to the prevailing airflow conditions. This hazard can arise, for example, from the operation of kitchen extractor hoods or from the reversal of airflow in the chimney, particularly in summer and especially in hot, humid weather. To minimize and preferably completely eliminate the hazards posed by smoldering and glowing fires, the invention proposes a separate soot bag (314), which can be operated in a wet state, at least and preferably optionally.If CO development is detected, the separate soot bag can advantageously be sprayed with an extinguishing agent such as water via nozzles, thus extinguishing the source of the fire and permanently preventing reignition. To ensure that the soot effectively enters the separate soot bag, a sloping base (316) can be installed in the area of ​​the bag's bottom. Ideally, in the event of a smoldering or glowing fire within the soot bag, the building's occupants and the responsible chimney sweep are notified. As an alternative to the optional wet operation, the separate soot bag can also be operated continuously with a sufficient quantity of water present at all times in the base area. This operating method requires more maintenance but is simultaneously more reliable, as malfunctions of nozzles, pumps, etc., are prevented.This variant corresponds to the so-called wet ash separator used in waste incineration plants. The illustration shows the separate soot bag on the right side of the diagram. Fig. 44 This was done there due to space constraints; it is particularly useful in conjunction with the E-filter (304) installed on top of the chimney, which cleans the chimney itself. Based on Fig. 44It can be illustrated by example that the flue gas path in normal combustion runs from bottom to top and can also have a certain lateral movement component, which is caused, for example, by filters 300 and 302 or by a horizontal rain cap on the chimney outlet. A downward flow direction does not correspond to the flue gas path in normal combustion operation. This will occur, for example, in the case of malfunctions such as blockages in the area of ​​the chimney outlet or with incorrectly operated kitchen extractor hoods, as well as in the combination of kitchen extractor hoods and leaking chimney masonry. Fig. 45 shows an example of a pocket filter with three filter pockets, viewed from top to bottom, with a left-to-right flow direction. The filter pockets are mounted in a frame (320).The upper filter pocket (322) is fully open, for example due to high gas velocities, so that its entire filter area is active. The middle filter pocket (324) is partially collapsed, for example due to very low flow velocities, so that only the filter area to the left of the contact point (328) is active and the filter area to the right of it (326) is inactive. In the lower filter element (330), a shaping element (332) is incorporated into the filter pocket, which prevents the filter pocket from collapsing even at low flow velocities. Ideally, the shaping element is lightweight, temperature-stable, and allows flow through it along the horizontal axis, so that the portion of the filter area to the right of the shaping element is also active.The shaping element can, for example, consist of PVDF, a plastic resistant to temperatures up to 160 °C, and be designed as a packing material normally used in process separation apparatus, e.g., for distillation, rectification, or gas scrubbing. Preferably, the shaping element can be made of plastic-free paper cups. These are even lighter, less expensive, and more environmentally friendly to dispose of than PVDF. Fig. 46 shows exemplary designs of devices that, in strong gusty winds, at least significantly limit and ideally completely prevent the propagation of negative pressure from the upper outlet of the cleaned flue gas into the fine dust filter according to the invention. In this illustration, the gusty wind (338) comes from the left and blows to the right.It has surprisingly been observed that, under strong gusty wind conditions, strands of flue gas can detach from the interior of the filter according to the invention, and that, contrary to all previous expectations, these strands can also be drawn in from below the extraction unit. In such cases, uncleaned flue gas escapes into the atmosphere via the bypass path around the filters. This effect contradicts the concept of the invention and should therefore be prevented. Internal components are proposed that, during undisturbed normal operation, provide a low flow velocity for the flue gas flow from bottom to top. In the event of a sudden, sharp increase in flow velocity, the flow resistance should increase significantly, so that the detachment of the raw gas strands is at least considerably reduced and ideally completely prevented.To ensure that the minimum cross-section of the exhaust path is not reduced by the installed components, their housing can have a larger cross-section. This is in . Fig. 46The widening in the lower part is shown. The upper gas outlet (340) of the filter according to the invention is depicted, with the separator located below not shown here. A rain guard (342) mounted above, optionally shown here by way of example in the form of a roof, prevents rainwater from entering the area of ​​the filter elements and also ensures that the displayed values ​​of the thermocouples are not distorted by evaporative cooling. In the left-hand illustration, various levels with openings for flue gas (344), shown here by way of example as staggered perforated plates, are provided, which cause an increased pressure drop in the event of a sudden increase in the flow velocity. The flue gas path in normal operation (346) meanders through the openings for the flue gas passage (350).In the right-hand illustration, the internal components in the flue gas path (348), which partially obstruct the passage of the flue gas, are shown here by way of example with offset openings (350) for flue gas passage. Additionally, internal components to increase the flow resistance (352) are provided, shown here by way of example as pipe sections that preferably project below the internal components, since this geometry is particularly suitable for generating high flow resistance at suddenly increasing flow velocities. The upper reduction of the upper outlet cross-section to a cross-section similar to the lower inlet cross-section, shown in the left-hand view, can also be provided in the embodiment shown on the right without being explicitly illustrated. Fig. 47 shows by way of example an arrangement suitable for reducing excessively strong negative pressures in the chimney.These excessively high negative pressures, which can be caused, for example, by a defective oven door seal or by operating errors, have a detrimental effect on the operation of the combustion system. This leads to increased flue gas losses, reduced efficiency, and higher emissions of carbon monoxide and particulate matter due to the lower combustion chamber temperatures resulting from incomplete combustion. The negative pressure is reduced by introducing air or flue gas (376), preferably cleaned recirculated flue gas, into the interior of the chimney via a supply line (360). Advantageously, an outlet valve (362) is provided that can interrupt the air or gas supply depending on the pressure, so that a certain minimum negative pressure in the chimney, for example 12 Pascals, is not undercut. The chimney is advantageously sealed against the environment by means of a seal (380), for example made of mineral fiber matting.Air can be supplied via a preferably weight-loaded pendulum damper (364), as is standardly used in chimney construction for negative pressure regulation. Alternatively, air or gas can be introduced into the chimney via an auxiliary fan (366), the performance of which is advantageously controlled by the pressure sensor (370). Alternatively, and preferably, a certain proportion of the warm, recirculated, cleaned, and, above all, warm flue gas can be introduced into the chimney. The fan (100) provides the recirculated, cleaned flue gas with a slight, but sufficient, overpressure to allow it to be drawn into the chimney interior even through smaller cross-sections of the supply line (360). The risk of creosote buildup in the chimney or wet operation of the filter due to condensation is lower when using warm flue gas than when using cold ambient air.To regulate the amount of flue gas introduced, a throttle valve (368) is provided, which is preferably controlled by the pressure sensor (370) so that a predetermined minimum negative pressure in the chimney is not undershot. Advantageously, in this variant as well, the outlet valve (362) prevents too much gas from being introduced into the chimney. A pressure sensor (370) is provided to monitor the negative pressure in the chimney, which can detect the internal pressure in the chimney via a connecting element (372). Preferably, the sensor can also detect the pressure in the installation room of the combustion unit (220) via another connecting element (374), so that the pressure sensor can accurately detect the pressure conditions relevant to the flue gas. Fig. 48 shows, by way of example, in the upper illustration, a section of the recirculation part (450) with the inner pipe (452) and the connection nozzle for clean gas (454), which is shown in more detail and in cross-section in the lower illustration.The inner tube (452) and the connection nozzle (454) for clean gas for recirculation are also visible in the lower illustration. When the clean gas, indicated by the light gray arrows, flows from the connection nozzle to the inner tube, it can take three different paths, as shown here. Due to the slide valve with the partially open section (462), at least one and at most two paths are always open, and the remaining paths are closed to the clean gas flow. In the transition area to the inner tube (452), two guide plates (456, 458) are shown as examples. These ensure that the gas flow in the upper path is deflected upwards towards the atmosphere. The lower guide plate (458) directs the gas downwards towards the combustion chamber when it flows via the lower path. Gas flowing via the middle path is introduced radially into the inner tube (452) without a vertical component.Depending on the position of the slide valve, the clean gas is directed in different directions before being introduced into the inner tube. The slide valve can be moved vertically and is limited by two end stops (464, 466) such that at least one free path for the gas flow is always open. In the lower left illustration, the slide valve is in its highest possible position, so that all the clean gas is directed upwards into the inner tube via the free section (462). In the lower right illustration, the slide valve is in its lowest possible position, limited by the lower end stop (466). In this position, the clean gas is introduced into the inner tube partly radially and partly downwards. A completely downward feed would also be possible, but would require a modification of the arrangement in which the upper closed section would be extended and the lower stop (466) would be moved further downwards.By recirculating the clean gas in various vertical directions, the pressure conditions in the chimney can be influenced, so that, for example, excessively strong negative pressures can be at least partially compensated for by directing a larger portion of the clean gas downwards, i.e., in the opposite direction to the raw gas rising from the combustion chamber. The advantage over the [other methods] is... Fig. 47 The advantage of the depicted variants lies in the fact that no downward-leading pipe (360°) is required. The amount of recirculated gas is also limited, so that the Fig. 48The preferred embodiment described is inherently safe against an excessive reduction in chimney negative pressure, which in extreme cases could lead to a reversal of the flue gas flow into the combustion chamber. In particular, the option with the additional fan (366) could lead to this malfunction in the event of a malfunction of the control unit or the pressure sensors, especially if the fan (366) were to blow in air instead of recirculation gas. In the Fig. 48This is not possible with the described variant. It is possible to compensate for excessively strong negative pressures in the chimney, regardless of whether they are due to operator error or technical defects. Under optimal pressure conditions, combustion emissions are lowest, thus extending the service life of the filter elements. A narrowing of the flow cross-section of the inner pipe, for example, by baffles protruding into the inner pipe, is generally unproblematic. It is important to ensure that these minor constrictions do not negatively impact combustion operation or flue gas discharge, for example, by causing excessive pressure loss in the constricted area. Ideally, the insignificance of such a constriction should be demonstrated both mathematically and practically.Alternatively, the distribution described above, preferably of the recirculated clean gas, can also be supplied to the respective channels via valves, control flaps, or similar devices, or, less preferably, the guide plate can be made movable, or alternatively, other methods for changing the vertical component of the incoming gas can be used. Fig. 49 shows an example of the filter according to the invention as a complete unit (400) on the left in a top view and on the right in a perspective view. The complete unit consists of the main components: the technical chamber (402), in which, among other things, the extraction and recirculation section (404) and the fan (166) are housed, as well as the filter chambers 1 for pre-filtration and 2 for fine filtration. The filter chambers 1 and 2 can, for example, be extended downwards, in particular supplemented downwards by a further chamber, in order to increase the installable filter area.In this case, a significant portion of the required operating volume is located below the original (before filter installation) chimney opening or chimney top. For example, two filter chambers 1 and one filter chamber 2 can also be installed if this is advantageous due to the chimney height and roof pitch. Advantageously, a spark arrestor (405) is installed upstream of the pre-filter. The fan is advantageously arranged on the clean gas side downstream of both filter chambers, so that the raw gas (130) coming from below from the combustion chamber is drawn via the extraction unit (lower part of 404) to filter chamber 1 (406), from there to filter chamber 2 (408), and from there as clean gas (134) to the fan (166), which directs it on its pressure side towards the recirculation section (upper part of 404) and from there upwards to the atmosphere. Fig.Fig. 50 shows an exemplary preferred embodiment of the filter according to the invention for manufacture from prefabricated panel components, which are particularly preferably mounted on an internal skeleton made of angle steel profiles and which consists of the frame for the technical chamber (410) and possible frame parts (412) for the filter chambers. Fig. 51 shows an exemplary top view of the complete unit (400) of the filter according to the invention in its assembled state. An exploded view shows the breakdown of the assembled unit into individual components, such as the side wall of the technical chamber (420), the maintenance door (422) to the technical chamber, the walls (424, 426) between the technical chamber and filter chambers 1 and 2, the maintenance doors (428, 430) of filter chambers 1 and 2, the front panels (432, 434) of filter chambers 1 and 2, and the side panels (436, 438) of filter chambers 1 and 2.Figure 52 shows an exemplary combination of the fine dust separation according to the invention with an architectural option for the lighting design of buildings with at least one light source (390), through which projections (392), for example as a static or moving image in aerosol clouds (394), are possible and which can advantageously be used in combination with a gas purification device (396) according to the invention and advantageously has a device for measuring wind direction and speed (398). The light source and also the device for measuring wind direction and speed can be installed either directly on the filter according to the invention (left illustration) or in its vicinity (right illustration). The left illustration is preferred because, regardless of wind direction, no shading by the chimney and the filter occurs and the wind conditions can be measured without interference.An embodiment in which the light source and / or the wind measurement is mounted above the filter is also part of the invention, even without an explicit pictorial and textual description. Fig. 53 shows an exemplary flue gas analysis, which preferably extracts the raw gas before it enters the filter via a measuring gas pump (474) and, for example, passes it over a packed quartz wool packing (470) and then over a CO sensor (472). Preferably, the measuring gas is then returned to an area of ​​the same pressure level, preferably also before the filter, so that the quantity of measuring gas extracted by the measuring gas pump is as constant as possible (for example, preferably extraction and return before the filter entry). Advantageously, the measuring gas is preferably diluted with cold ambient air after extraction, so that the tars condense more readily due to the cooling and the service life of the CO sensors is extended.Alternatively, an additional measuring gas pump can be used for dilution, so that the dilution ratios are expected to be more uniform than with purely suction-based dilution. Preferably, such measuring lines can be implemented redundantly, optionally with different run times per combustion cycle. Fig. 54 shows an exemplary embodiment of the cleaning device (left in the side view and right in the top view), particularly for the pre-filter, by mechanical movement, in which the filter bags (480) are at least partially surrounded by shaking bars (484) and can be set in motion together via a shaking frame (482). Fig. 55 shows an exemplary assembly option in the right-hand figure, in which the technical housing (490) is connected to a base plate (496) by means of threaded bolts (500), which in turn are connected to the chimney (100) via other threaded bolts (498), preferably by gluing.The filter chambers are mounted on the side of the technical housing; the pre-filter chamber (492) is shown here. The middle image shows a top view in which the filter chambers for pre- and fine cleaning (492, 494) are attached to the side of the technical housing (490). In this top view, the chimney (100) is concealed by the technical housing, which here exemplifies the extraction and recirculation unit as well as peripheral components such as the control unit and fan, which are not shown separately for clarity. The right image shows a side view of the fully assembled unit, in which the lower skirt of the slip-on head design (502) is shown as a dashed line. This lower skirt integrates the contours of the chimney filter, which protrude from the chimney, into a larger overall contour of the same geometry compared to the initial assembly.By combining techniques such as foil application and digital photo printing, the fireplace looks almost exactly as it did before; the rather slight difference in size will only be noticeable upon very close inspection and knowledge of its condition before installation.

[0140] The embodiments of the invention shown in the figures of the drawing and the embodiments of the invention described in connection with these embodiments of the invention serve only to explain the invention and are not limiting for the invention. Reference symbol list:

[0141] 10 Flue gas path 20 Bypass path 21 Core area of ​​the bypass zone between extraction and recirculation 22 Thermal separation 24 Flue gas damper 26 Collection chamber 28 Discharge of separated fine dust 30 Extraction unit 34 Extraction opening 38 Connecting element between extraction unit and filter unit 40 Recirculation unit 48 Connecting element between filter unit and recirculation unit 50 Filter element (depth filter or E-filter) 60 Filter unit 66 Inlet opening into the filter unit 68 Outlet opening from the filter unit 70 Partition between pre-filter and fine filter material 72 Silencer 76 Switching unit 78 Additional filter, preferably for start-up operation with fresh bag filters T1 Temperature sensor below the extraction 100 Chimney 102 Chimney mounting as a complete unit 104 Chimney mounting, vertical bracket 106 Chimney mounting, horizontal struts 108 Chimney mounting, upper struts 110 Connection plate 112 Connection pipe 120 Extraction and recirculation piece as a complete unit,Optional: only extraction piece, also called chimney connection piece 122 Extraction section, lower part of the overall unit 120 124 Recirculation section, upper optional part of the overall unit 120 130 Flue gas, here: raw gas, uncleaned from the combustion 132 Extracted raw gas towards the filter chamber (150) 134 Recirculation gas, return of clean gas from the filter chamber (150) 136 Upper outlet of clean gas towards the atmosphere 138 Outlet of uncleaned raw gas into the atmosphere 140 Open openings for flue gas flow 142 Openings closed for flue gas, here for example screwed shut with blanking plates 150 Filter chamber as an overall unit, shown here by way of example with an inserted pocket filter with three filter pockets, the raw gas coming from the combustion flows through the upper nozzle (152) from above into the filter pockets and leaves the filter chamber via the lower Nozzle (154), preferably thermally insulated,for example, made of a sandwich material of galvanized sheet steel and rock wool 151 Housing of the filter chamber, shown here as an example with upper maintenance access for changing the bag filters 152 Nozzle in filter chamber for raw gas inlet 153 Top plate for holding the bag filter and for separating the raw gas space from the clean gas space 154 Nozzle in filter chamber for clean gas outlet 156 Bag filter,Shown here as an example with three filter pockets 157 large filter pockets 158a small filter pocket 158 ​​Exemplary representation of the pocket filter (156) with a filter area (158) encompassing the three filter pockets for fine separation 160 Housing for peripheral technology as a complete unit for fan (166) and control (not shown) as well as optional silencer (168) and additional filter for start-up operation (not shown here) 162 Connection in peripheral technology housing for clean gas inlet 164 Connection in peripheral technology housing for clean gas outlet 166 Fan 168 Silencer 170 Cover for item 120, optionally with insulation 172 Additional volume for operational equipment 180 Classic snap-on cover, according to the state of the art 182 Inner part of the snap-on filter 184 Filter chamber(s) of the slip-on filter 186 Housing for peripheral technology of the slip-on filter, preferably for housing control and fan,optionally also for additional filter element and silencer 188 outer casing of the slip-on filter, optionally equipped with photovoltaic modules on the outside(s) 190 ventilated plate(s) 192 insulating layer 200 photovoltaic cells 202 low voltage, preferably direct current 204 alternating voltage, for example 220 / 380 V 206 inverter 208 device for fine dust separation, designed as an electrostatic precipitator or depth filter, only the external view is shown here 210 Peltier element 212 cooling of the Peltier element 214 (re-)cooling of the Peltier cooling (212) against the environment 216 overheating protection with liquid, which is preferably frost-protected, non-toxic and non-flammable and has a boiling point significantly above 100 °C. 218 (Re-)cooling for overheating protection 216, preferably for steam of the boiling liquid, preferably against the environment 219 Particle and droplet separator, preferably designed as a knitted separator 220 Combustion,especially solid fuel small combustion 222 Exhaust gas (air) heat exchanger 224 Fan for exhaust gas (air) heat exchanger 226 Fine dust filter (fan not shown) 228 Chimney 230 Air, here: supply air to the furnace, quality: ambient air, optionally with or without preheating by the exhaust gas (air) heat exchanger 232 Air, here specifically: warm air from the environment 234 Air, here specifically: supply air to the fan of the exhaust gas (air) heat exchanger, quality: ambient air 236 Raw gas, combustion exhaust gas with high fine dust load 238 Clean gas, combustion exhaust gas with low fine dust load 250 Exhaust gas (air) heat exchanger, here by way of example as a shell and tube heat exchanger 252 Inlet nozzle for cold medium, preferably air, preferably on the jacket side 254 Outlet nozzle for heated medium, preferably air 256 Fan for feeding from position 250 via nozzle position 252 258 heat exchanger pipes,preferably exhaust gas-carrying 260 warm exhaust gas 262 cooled exhaust gas 264 temperature sensor for controlling the fan, preferably downstream of the exhaust gas (air) heat exchanger 266 exhaust pipe, preferably as a single pipe 268 exhaust gas heat exchanger, shown here by way of example as a pipe-in-pipe design; alternative designs such as pipe-in-(square) shaft, shown here without separate illustration 270 vertical housing wall, for example galvanized sheet steel and rock wool in sandwich construction 272 horizontal housing wall, for example galvanized sheet steel and rock wool in sandwich construction 274 sealant between the housing walls, for example high-temperature silicone 276 outer mounting plate 278 inner mounting plate, for example angled 280 fastening means, for example steel rivets 300E filter with storage of the separated and cleaned fine dust outside the flue gas path,Here, an example is shown near the flue outlet and to the side of the flue gas path: 301E filter with storage of the separated fine dust in the flue gas path, here shown in the exhaust pipe within the room where the stove is installed, without a picture of the spray electrode. 302 Deep filter with storage of the separated and cleaned fine dust outside the flue gas path, here shown near the flue outlet and to the side of the flue gas path. 303E filter with storage of the separated fine dust in the flue gas path, here shown in the chimney (optionally also near the flue outlet), with a picture of the spray electrode. 304E filter with storage of the separated and cleaned fine dust outside the flue gas path, here in the lower part of the chimney flue (310). 305 Separated fine dust, here stored near the flue outlet and to the side of the flue gas path. 306 Separated fine dust.Here, for example, in the pipe between the stove and the chimney within the stove's installation room, 307 separated fine dust, here for example in the chimney, for example as adhesion to the side walls, 308 optional drainage for separated and cleaned fine dust, 310 separated and cleaned fine dust, here for example in the lower area of ​​the chimney flue (soot bag), to be removed via the cleaning opening 312, 312 cleaning opening for cleaning by chimney sweep, 314 separate soot bag for storing both the heavy fraction of soot and the light, agglomerated and cleaned fluffy soot separated by a fine dust separator, preferably optionally operable wet in the case of smoldering and glowing fires, for example by injecting water or another extinguishing agent and alternatively permanently operated wet, i.e. a liquid volume, preferably water, is permanently located in the lower area of ​​the separate soot bag.so that all falling soot is immediately fed into the water. Optionally, the separate soot bag is mobile, for example, equipped with wheels to facilitate maintenance. Preferably, the separate soot bag is permanently connected to the chimney with a free passage. Therefore, it is advantageously designed in accordance with the regulations for fire protection class F90. 316 Sloping floor at the lower end of the soot bag, for feeding the soot falling from above towards the separate soot bag (314) 318 Technical chamber of the separate soot bag, advantageously containing at least one CO sensor for detecting smoldering and glowing fires and with extinguishing agent, e.g., water supply, advantageously with a signaling or transmitting device in the case of smoldering and glowing fires 320 Frame of pocket filter, here shown by way of example with three filter pockets, flowing from left to right 322 Upper filter pocket, open and in ideal shape,held in shape by gas flow at high flow velocities 324 middle filter pocket, partially collapsed, for example due to low flow velocities, 326 rear part of the middle filter pocket 324, not or only poorly permeated, collapsed 328 point from which the middle filter pocket has collapsed, so that only the open part to the left of it contributes to filtration, while the collapsed part to the right of it is inactive 330 lower filter pocket into which a shaping element 332 is inserted, which prevents the pocket from collapsing even at low flow velocities 332 shaping element, advantageously made of temperature-resistant material, preferably permeable, embodiment for example as a packing body made of the temperature-resistant plastic PVDF or as a plastic-free cardboard cup,ideally with an additional opening in the base (here on the right side) 338 (side) wind 340 Upper gas outlet of filter according to the invention, wherein the separator located below is not shown here 342 Rain protection, optional, shown here by way of example in roof form 344 Levels with openings for flue gas, shown here by way of example as offset perforated sheets 346 Path of the flue gas 348 Installation in flue gas path, which partially prevents the passage of the flue gas, shown here by way of example with offset openings (350) for the flue gas passage 350 Openings for flue gas passage 352 Installations to increase the flow resistance, shown here by way of example as pipe sections, which preferably project below the installations 360 Supply line for air or gas into the chimney 362 Optional outlet valve for air or gas into the chimney, preferably closing,as soon as the negative pressure in the chimney falls below a minimum value of, for example, 12 Pa compared to the pressure in the combustion chamber, 364 damper for supplying air or gas to 360, preferably designed as a weight-loaded pendulum damper 366 additional fan for supplying air or gas to 360, preferably power-controlled via pressure sensor 370 368 throttle damper for supplying gas to 360, preferably flow-controlled via pressure sensor 370 370 pressure sensor for monitoring the negative pressure in the chimney 100 372 connecting element from pressure sensor 370 to the interior of the chimney, preferably as a temperature-resistant metal pipe, for example made of copper 374 connecting element from pressure sensor 370 to the combustion chamber, for example designed as a metal or hose pipe 376 air or gas introduced into the chimney to reduce the negative pressure 380 sealing of the chimney, for example designed as a mineral fiber mat 390 Light source 392 Projection,for example as a static or moving image 394 Aerosol cloud 396 Gas purification device according to the invention 398 Device for measuring wind direction and speed 400 Complete unit of the filter according to the invention 402 Top view of the technical chamber, shown here with extraction and recirculation section 404 and fan 166, further technical components, such as control, cleaning or knocking device and fluid tank for nozzle system are not explicitly shown here for the sake of clarity 404 Extraction and recirculation section 404 as a complete unit, consisting of the components extraction unit 30 and recirculation unit 40, shown here with external insulation 406 Filter chamber 1, with pre-filter and maintenance cover, the cleaning or knocking device and the nozzle system are not explicitly shown here for the sake of clarity 408 Filter chamber 2, with fine filter and maintenance cover,preferably without cleaning or knocking device and nozzle system 410Frame for technical chamber (402) as an internal skeleton for the parts of the filter chambers, which are exemplarily designed as sandwich panels, exemplarily made of angle steel with dimensions 40 x 40 x 2 mm, so that, among other things, wind loads can be absorbed by the entire unit and transferred to the chimney via the base fixing 412Frame part as an internal skeleton for the filter chambers, exemplarily made of comparable angle steel as in 410 420Side wall of technical chamber (402), firmly connected to the entire unit, here exemplarily made of sheet steel 422Maintenance door to technical chamber (402), preferably removable, here exemplarily made of sheet steel with ventilation slots 424Wall between technical chamber and filter chamber 1, with opening for raw gas passage from the extraction section to the filter chamber 1, preferably in sandwich panel construction (steel, insulating material, steel),426Wall between technical chamber and filter chamber 2, with opening for clean gas passage from filter chamber 2 to the fan 428Maintenance door of filter chamber 1, shown here removable and with two handles, preferably in panel construction 430Maintenance door of filter chamber 2, shown here removable and with two handles, preferably in panel construction 432Front panel of filter chamber 1, preferably in panel construction 434Front panel of filter chamber 2, preferably in panel construction 436Side panel of filter chamber 1, preferably in panel construction 438Side panel of filter chamber 8, preferably in panel construction 450Cutout of recirculation section, introduction of recirculated flue gas into the chimney 452Inner pipe of the recirculation section 454Connection nozzle for clean gas for recirculation 456Upper guide plate 458Lower guide plate 460Slider with openings for gas flow and closed part; rotated 90° in this representation,so that the open and closed surfaces become visible 462 Part of the slide open for gas flow 460 464 Upper end stop for slide 460 468 Lower end stop for slide 460 470 Dust and tar separator, preferably made of packed quartz wool (quartz wadding) or comparable prefabricated unit, alternatively made of such units, but with glass wool instead of quartz wool 472 CO sensor 474 Measuring gas pump 476 Dilution of the measuring gas 480 Filter bags 482 Shaker frame 484 Shaker rods 490 Technical housing 492 Filter chamber for pre-filter 494 Filter chamber for fine filter 496 Base plate 498 Threaded bolts for fastening the base plate in the chimney, preferably glued in 500 Threaded bolts for fastening the base plate to the chimney filter according to the invention, here by way of example to the technical housing 502 Lower apron the slip-on head design,

Claims

1. Apparatus for filtering fine dust, in particular for small solid fuel combustion plants, comprising an extraction unit (30) comprising - a connecting pipe (112) for connecting the extraction unit (30) to a flue gas duct (10) through which flue gas (130) flows from a combustion chamber, and - an extraction opening (34), and a filter unit (60) comprising - an inlet opening (66) connected to the suction opening (34), - an outlet opening (68), and - a filter element (50) arranged between the inlet opening (66) and the outlet opening (68), wherein the extraction unit (30) and the filter unit (60) with filter element (50) are arranged in at least one assembly, and the filter element (50) of the filter unit (60) is designed as a depth filter and / or comprises an electric filter (E-filter), characterised in that as a safeguard against smouldering or smoldering fires involving the separated and stored quantities of fine dust and / or as a safeguard against the uncontrolled and unnoticed spread of potentially hazardous carbon monoxide emissions, a monitoring system for the gaseous atmosphere in the area where the separated and cleaned fine dust is stored which measures the carbon monoxide content when the apparatus is not in filtration mode, whereby the combustion process is not in operation and therefore no flue gas and no carbon monoxide (CO) is present or should be present in the area where the fine dust is stored, whereby the monitoring detects an increase in the carbon monoxide content as an indicator of a starting smouldering or smouldering fire, wherein the depth filter provides, as a filter element (50), a filter material made of plastic or plastic fibres, metal or metal fibres, textile, felt, and / or ceramic, which is designed to separate fine dust, condensate and / or condensate components, wherein the filter element (50) is designed as a pocket, a bag or a tubular filter.

2. Apparatus according to claim 1, characterised in that, as a safeguard against smouldering fires involving the separated and stored quantities of fine dust and / or as a safeguard against the uncontrolled and unnoticed spread of potentially hazardous carbon monoxide emissions, a wetting device is further provided, which operates both proactively, by hydraulic compaction of the fine dust, which is particularly loose after cleaning, and reactively as an extinguishing device in the event of a detected smouldering fire through detection as part of the monitoring of the carbon monoxide content (CO monitoring).

3. Apparatus according to claim 1 or claim 2, characterised in that, as a safeguard against smouldering or smouldering fires involving the separated and stored quantities of fine dust and / or as a safeguard against the uncontrolled and undetected spread of potentially hazardous carbon monoxide emissions, when a depth filter is used as the filter element (50) of the filter unit (60), at least one spark arrester (405) is provided, preferably upstream of a pre-filter (52) in the direction of flow during normal operation, i.e. between the combustion chamber and the pre-filter (52), and / or when an electric filter (E-filter) is used as the filter element (50) of the filter unit (60), at least one spark arrestor is provided, which is arranged in such a way as to prevent the entry of sparks originating from the combustion chamber in the direction of the stored and cleaned fine dust.

4. Apparatus according to any one of claims 1 to 3, characterised in that, when an electric filter (E-filter) is used as the filter element (50) of the filter unit (60), a volume space is provided outside the flue gas path during normal operation of the combustion chamber in order to be able to store or accommodate the fine dust separated in the electric filter (E-filter) after cleaning can be stored or accommodated for such a duration that cleaning within a heating period is not required, or at least one separate soot bag (314) is provided, which can be wetted in the event of smouldering or smouldering combustion detected during monitoring of the carbon monoxide content (CO-monitoring) or alternatively is operated in a permanently wet state.

5. A device according to any one of claims 1 to 4, characterised in that when a depth filter is used as the filter element (50) of the filter unit (60), the specific filter area [m2 / kWth], relative to the output of the combustion system [kWth], of at least one pre-filter (52). also in unknown or adverse operating conditions, remains within the range of 0.01 to 1.0 m2 / kWth , preferably 0.1 to 0.8 m2 / kWth and even more preferably 0.2 to 0.7 m2 / kWth , or provided that unfavourable operating conditions can be sufficiently reliably ruled out, it can be limited to the range of 0.03 to 0.3 m2 / kWthand can then preferably be operated in the range of 0.05 to 0.2 m2 / kWthand particularly preferably at 0.1 m2 / kWth.

6. A device according to any one of claims 1 to 5, characterised in that the filter element (50) of the filter unit (60) comprises • an electrical filter (E-filter) which is preferably capable of being cleaned automatically, • a depth filter which, when installed within the filter unit (60) can be cleaned preferably by mechanical movement and particularly preferably automatically, which has at least one of the four properties listed below • a pre-filter (52) in accordance with filter class G4, M5, M6, F7 or F8 in accordance with EN 779 and a fine filter (56) in accordance with filter class M5, M6, F7 to F9 or E10 to E12 in accordance with EN 779 • a series connection of more than two filter materials or a graded filter material comparable to a series connection of more than two filter materials • a combination comprising a pre-filter (52) of filter class G4, M5, M6, F7 or F8 in accordance with EN 779 and a fine filter (56) in accordance with filter class M5, M6, F7 to F9 or E10 to E12 in accordance with EN 779, or a series connection of more than two filter materials, or a graded filter material comparable to a series connection of more than two filter materials, in particular a graded depth filter material, which possesses at least one of the following two properties: • the same separation efficiency as the combination of pre-filter (52) and fine filter (56) or • the same service life as the combination of pre-filter (52) and fine filter (56) described above • a combination of more than two filters (pre-filter and fine filter) which possesses at least one of the following two properties: • the same separation efficiency as the combination of pre-filter (52) and fine filter (56) described above, or • the same service life as the combination of pre-filter (52) and fine filter (56) described above.

7. A device according to any one of claims 1 to 6, characterised in that the depth filter comprises at least one shaping element (58) which is adapted to counteract the collapse of filter elements.

8. A device according to any one of claims 1 to 7, characterised in that the device has at least one of the following safety- and / or emission-related mechanisms, where the following points are included among the safety-related mechanisms: - carbon monoxide monitoring of the storage location or locations of the cleaned particulate matter, preferably with notification to the operator and / or a chimney sweep; - a quenching or wetting device at least for the storage locations of the fine dust; and the following points relate to emission-relevant mechanisms: - at least partial compensation for insufficient negative pressure in the flue, whereby a gas is introduced into the flue gas path to influence the pressure; - monitoring of carbon monoxide and tar levels in the raw gas, in particular to monitor user behaviour, as well as in particular with regard to a possible reduction in the generation of fine dust in the combustion chamber and technical defects in the entire system (combustion chamber, flue, leaks, e.g. in stove doors, flue masonry, etc.).

9. A device according to any one of claims 1 to 8, characterised in that the device is designed to be soot-fire-proof by means of at least one of the following measures, i.e. • it comprises at least one rear-ventilated, preferably metallic plate; • is sealed, at least in the lower region of the device's housing, against the escape of, for example, molten plastic, preferably by at least partially and even more preferably predominantly metallic labyrinth seals; • it comprises at least one insulating layer, preferably a temperature-resistant insulating layer, preferably resistant to temperatures of at least 1,000°C; • provides proactive detection of soot fires by preferably at least one CO sensor, particularly preferably by at least two CO sensors, which are installed in the direction of flow of the flue gas before and after the filter chamber(s), and particularly preferably by at least two CO sensors, which are installed before the first filter chamber and after the fan; and extinguishing of a detected soot fire by introducing a wetting agent, preferably in the form of water, particularly preferably in the form of water enriched with antifreeze, via at least one introduction of the wetting agent, which is preferably located on the upstream side of at least one filter stage with at least one a) single-fluid nozzle, preferably a single-fluid spray nozzle, and / or b) at least one two-fluid nozzle.

10. Apparatus according to any one of claims 1 to 9, characterised in that the pre-filter consists of filter material with a basis weight of 200 to 300 g / m2, preferably 225 to 275 g / m2, and is particularly preferably calendered on one side on the clean gas side, i.e. heat-treated for consolidation, and / or thermally consolidated without chemical binders and / or has a progressive structure of the fibres or fibre layers.