DEVICE FOR CLEANING EXHAUST FUMES FROM A FIRE PIT

Description

[0001] The present invention relates to a device for cleaning exhaust gases from a fireplace.

[0002] Recently, increased environmental awareness among the population has shifted attention not only to private transport, but also to the heating of residential and commercial spaces with fireplaces, such as biomass heating systems. In particular, the filtration of particulate matter and harmful accompanying substances from the exhaust gases of such fireplaces has now been required by law in many countries, and the World Health Organization is in the process of setting very low limit values ​​for many pollutants. Since the requirements for such fireplaces are expected to become even more stringent in the future, complex redesign or retrofitting measures will be necessary for future and existing fireplaces.This raises the particular question of what a compact solution for cleaning exhaust gases from fireplaces could look like, which should be modular if necessary and ideally clean the exhaust gases from the fireplace to such an extent that a chimney can be completely replaced, i.e. only completely cleaned air at an acceptable temperature and without any significant pollutants emerges from the device.

[0003] A generic device for purifying exhaust gases is known, for example, from DE 10 2015 103337 A1. For the sake of completeness, reference is also made to US 2016 / 107120 A1 and AT 412 533 B.

[0004] Furthermore, for optimal operation of the respective fireplace, it may be desirable to operate it independently of the room air, i.e. to supply air from outside the corresponding room.

[0005] To achieve the above-mentioned objects and to provide a device for cleaning exhaust gases from a fireplace, with which future limit values ​​for pollutants can also be complied with and which is nevertheless both compact and easy to retrofit in existing fireplaces, it is proposed according to the invention that this device comprises: a housing which accommodates functional components of the device, an inlet section which is intended to receive exhaust gases from the fireplace, an outlet section which is intended to discharge exhaust gases from the device, a bypass section which is designed to establish a direct connection between the inlet section and the outlet section and which can be closed by means of a first mechanical flap arrangement, and a cleaning section,which extends between the inlet section and the outlet section for guiding an exhaust gas flow and is provided with a plurality of functional components. The functional components include at least one electrostatic filter unit for separating fine dust particles, a centrifugal separator unit for expelling particles from the exhaust gas, and a fan unit for driving a flow of the exhaust gas through the purification section.

[0006] By accommodating functional components, and in particular all components responsible for cleaning the exhaust gas, within a single housing according to the invention, a compact and user-friendly unit can be created, which is also particularly suitable as a retrofit solution for existing fireplaces. The bypass section is provided to ensure the operational reliability of the device in the event of a failure of the device, in particular the blower unit. Furthermore, the first mechanical flap unit assigned to the bypass section can serve as a type of throttle valve, so that the draft generated by the blower unit can be adjusted by means of the adjustable return flow rate.

[0007] Furthermore, for safety reasons, the first mechanical flap arrangement can be designed such that it is always open when the device is de-energized.

[0008] It is understood that, in addition to the electrostatic filter unit and the centrifugal separator unit, further functional components may be arranged in the cleaning section, each of which acts specifically on individual components of the exhaust gases. For example, a catalyst unit may be provided for the catalytic treatment of the exhaust gases, which may in particular be a catalyst with an active coating. In order to achieve optimal efficiency of such a catalyst unit even when the exhaust gas is still cold, for example in a state shortly after the fireplace is started up, the device may further comprise an upstream heating device for heating the exhaust gases before they enter the catalyst unit, so that the exhaust gases can be preheated to an optimal oxidation temperature when they themselves are actually still too cool.For this purpose, for example, an electrically operated heating coil can be considered, which is suitably arranged in the exhaust gas flow path upstream of the catalyst unit.

[0009] Alternatively or additionally, the functional components for treating the exhaust gases in the exhaust stream can further comprise an injection unit for spraying a liquid agent and / or an irradiation unit, in particular an ultraviolet irradiation unit. A suitable liquid agent for treating the exhaust gases can be sprayed into the exhaust stream in very fine droplets, which can, on the one hand, trigger chemical reactions between the agent and certain gaseous components of the exhaust gas and, on the other hand, allow fine dust particles to agglomerate early in the treatment chain. Irradiation, in particular by means of an ultraviolet radiation source, can also trigger further chemical reactions of components of the exhaust gas in order to convert them or render them harmless.

[0010] In order to enable an energetically optimized operation of the device according to the invention, the device can further comprise, as a functional component, an exhaust gas heat exchanger which is designed to extract heat from the exhaust gas flow, and / or a thermoelectric generator and / or a silencer element.

[0011] In order to further influence the parameters of the combustion process in the fireplace using the device according to the invention, the functional components can further comprise a supply device for combustion air to the fireplace, wherein this supply device can further comprise at least one of a heating unit for the combustion air, in particular a heat exchanger, which is arranged and configured to transfer heat from the centrifugal separator unit and / or pipes through which exhaust gas flows to the combustion air, and a second mechanical flap unit for controlling the flow rate of combustion air. Through these measures, both the temperature and the flow rate of the combustion air supplied to the fireplace can be influenced, so that these parameters can each be set to optimal values ​​for the most efficient combustion possible.Furthermore, by supplying combustion air through the device according to the invention, the supply of room air to the fireplace can be dispensed with if the device itself draws the combustion air from outside the room in which the fireplace is located. Furthermore, the second mechanical flap unit can be used to protect against the unwanted escape of warm air into the environment if it is closed when the device is cold.

[0012] According to the invention, the device according to the invention comprises a controllable draft regulator associated with the outlet section, which can be adjusted such that the pressure conditions within the device, or in bypass mode, the pressure conditions of the fireplace, are not negatively influenced by the chimney draft. In embodiments in which the system is operated without a chimney, the air exiting the outlet section must be diverted accordingly.

[0013] Furthermore, the device according to the invention further comprises a control unit which is configured to control the controllable draft regulator and, if appropriate, at least one of the functional components and / or at least one of the flap assemblies. In the nomenclature of the present application, this control unit is initially not counted among the functional components, since it can be provided either inside or outside the housing of the device and has no direct influence on the exhaust gases to be purified. The control unit can be implemented by any known means, such as a microcontroller with a permanently installed memory or similar data processing means.Furthermore, the control unit can be connected to sensor units that provide data about the exhaust gases, for example, regarding their temperature, flow rate, and / or chemical composition, at one or more locations within the device. Based on these data, the control unit can then make appropriate adjustments to the components of the device it controls. Furthermore, the control unit can be used via a communications module to read out various data, such as the operating hours of the device and other parameters. For this purpose, coupling to a mobile device running dedicated software or direct connection to a display device via a wired or wireless connection is conceivable.

[0014] Furthermore, a positioning device can be assigned to the housing of the device according to the invention, in particular height-adjustable feet and / or a device for fastening to an external component, whereby the installation of the device with respect to existing fireplaces is facilitated and by adapting the positioning of the housing to different types of fireplaces, the device according to the invention can be installed as a "plug and play" component.

[0015] By making the housing fireproof in one embodiment of the invention, the device can also be designed to be suitable for installation in residential areas.

[0016] Furthermore, the device according to the invention can comprise a cleaning connection for an ash vacuum cleaner in the area of ​​the centrifugal separator unit in order to be able to remove ash accumulating there easily and cleanly.

[0017] Finally, the present invention relates to a system for heating a room, comprising a fireplace, a device according to the invention coupled to the fireplace by its inlet section as just described and optionally a chimney coupled to the outlet section.

[0018] Further features and advantages of the present invention will become even clearer from the following description of an embodiment when considered together with the accompanying figures. These show in detail: Fig. 1 shows an embodiment of a device according to the invention in a schematic isometric view; and Fig. 2 shows the device from Figure 1 in a side cross-sectional view.

[0019] The Figures 1 and 2each show an embodiment of a device 10 according to the invention for cleaning exhaust gases from a fireplace not shown in the figures. In the schematic isometric view of Figure 1 a part of the housing 12 is removed to highlight the components of the device provided inside it, while in Figure 2 a side cross-sectional view of the same device 10 is shown. It should also be noted that the housing 12 may be provided with suitable thermal insulation on its inside.

[0020] Except for an inlet section 14 for receiving exhaust gases from the fireplace (not shown) and an outlet section 16 for discharging exhaust gases from the device 10, the housing 12 is closed with respect to the flow of exhaust gases. Between the inlet section 14 and the outlet section 16, a bypass section 18 is also provided, which can be closed by a first mechanical flap arrangement 20 and forms a direct connection between the inlet section 14 and the outlet section 16. In particular, for safety reasons, the flap arrangement can be configured such that it is always open when the device 10 is de-energized.

[0021] On the other hand, a cleaning section 22 is located within the housing 12, through which the exhaust gases pass for cleaning when the bypass section 18 is closed. The functional components provided in this cleaning section 22, which are described below, can also be arranged in other orders, and not all of the components need to be installed in every device according to the invention; however, the embodiment shown here represents a particularly advantageous configuration.

[0022] The exhaust gas entering through the inlet section 14 is first optionally heated by a controllable heating device 24, for example if a sensor unit (not shown) determines that it is still too cool for the subsequent treatment steps, or also by means of a time recording device coupled to the fireplace, by means of which a time can be determined during a warm-up operation of the controlled fireplace during which the exhaust gases and the subsequent components are not yet in an optimal thermal range for cleaning them.

[0023] The exhaust gases then pass through a catalyst unit 26 with an active coating for catalytic treatment of the exhaust gases, followed by a thermoelectric generator 28 for generating or recovering energy. An irradiation unit 30, in particular an ultraviolet irradiation unit, can then be provided to trigger further chemical reactions of components of the exhaust gases.

[0024] Within the subsequent riser section of the purification section 22, an exhaust gas heat exchanger 32 is provided, which is also used to recover thermal energy from the now partially treated exhaust gases. At the upper end of the riser section mentioned above, there is also an injection unit 34 for injecting a liquid treatment agent for the exhaust gases, which can contribute, on the one hand, to the chemical conversion of undesirable gaseous components of the exhaust gases and, on the other hand, to the agglomeration of particulate matter components of the exhaust gases.

[0025] The exhaust gases then enter the area of ​​an electrostatic filter unit 36 ​​for separating fine dust particles. Electrostatic charging causes the particles to agglomerate, resulting in larger, more easily separated particles. These are then collected by a centrifugal separator unit 38 and can be removed and disposed of at an appropriate time through an opening 40. In particular, a cleaning connection for an ash vacuum cleaner can be provided at this point. The separator unit 38 can comprise, for example, a direct-current or cross-current cyclone.

[0026] Finally, the now purified exhaust gases pass through a fan unit 42, which creates a suction effect to drive the exhaust gases through the previously described components. The exhaust gases can then be fed to the outlet section 16 and discharged through it, for example, to a downstream chimney (not shown). A controllable draft regulator 44 is arranged in the area of ​​the outlet section 16 for adjusting the draft.

[0027] In addition to the exhaust gas cleaning section 22 just described, the device 10 further comprises a supply device 46 for combustion air from the surroundings of the device 10 to the fireplace (not shown). This supply device 46 comprises, in particular, an inlet opening 48 for fresh air from the surroundings of the device 10 and a combustion air supply 50 to the combustion chamber of the fireplace, which can be controlled by means of a second mechanical flap unit. Because the air taken at the inlet opening 48 originates from outside the room in which the fireplace is located, it can be completely independent of the ambient air. This can be achieved, for example, by connecting a nozzle of a pipe leading from the corresponding room to the inlet opening 48, or by arranging the device 10 itself outside the corresponding room.In such a case, only one pipe would have to be provided between the fireplace and the inlet section 14 and the combustion air supply 50.

[0028] During operation of the device 10, for example, the heat extracted from the exhaust gas in the heat exchanger 32 can be transferred to the combustion air to be supplied to the combustion chamber, so that the second mechanical flap and the heat exchanger 32 can adjust the combustion air in terms of its quantity and temperature for optimally efficient operation of the fireplace.

[0029] Furthermore, attention should be drawn to the control unit 52, which is located at the bottom of the housing 12 of the device 10 and is in data communication with all of the above-described controllable components of the device 10 for controlling them, as well as being coupled to sensor units for detecting parameters of the exhaust gas and / or the combustion air in order to be able to carry out control processes with the aid of the above-described components for optimal operation of the device 10. Merely as an example of such a sensor unit, reference numeral 54 indicates a connection for a measuring probe for detecting properties of the purified exhaust gases in the region of the outlet section 16.

[0030] Furthermore, the control unit can be used to read various data, such as the operating hours of the device and other parameters, via a communication module (not shown). For this purpose, coupling with a mobile device running dedicated software or direct connection to a display device via a wired or wireless connection is conceivable.

[0031] Finally, in the figures, immediately in front of the outlet section 16, a silencer element 56 for structure-borne sound and airborne sound is shown, which is used for noise minimization and housing insulation.

Claims

1. Apparatus (10) for cleaning exhaust gases from a fireplace, comprising: - a housing (12) which accommodates functional components of the apparatus; - an inlet section (14), which is intended to receive exhaust gases from the fireplace; - an outlet section (16), which is intended to discharge exhaust gases from the apparatus; - a bypass section (18) which is adapted to establish a direct connection between the inlet section (14) and the outlet section (16) and which can be closed by means of a first mechanical flap arrangement (20); and - a cleaning section (22) which extends between the inlet section (14) and the outlet section (16) for guiding an exhaust gas flow and is provided with a plurality of functional components, - wherein the functional components comprise at least: ∘ an electrostatic filter unit (36) for separating fine dust particles; ∘ a centrifugal separator unit (38) for removing particulates from the exhaust gas; and ∘ a blower unit (42) for driving a flow of exhaust gas through the cleaning section (22), characterised in that a controllable draught regulator (44) is assigned to the outlet section (16), and the apparatus (10) further comprises a control unit (52) which is adapted to control the controllable draught regulator (44).

2. Apparatus according to claim 1, wherein the first mechanical flap arrangement (20) is configured such that it is always open when the apparatus (10) is in a de-energised state.

3. Apparatus (10) according to claim 1 or 2, wherein the functional components further comprise: - a catalyst unit (26) for catalytic treatment of the exhaust gases, optionally with an upstream heating device (24) for heating the exhaust gases.

4. Apparatus (10) according to any of claims 1 to 3, wherein the functional components for treating the exhaust gases in the exhaust gas flow further comprise: - an injection unit (34) for injecting a liquid agent and / or - an irradiation unit (30), in particular an ultraviolet irradiation unit.

5. Apparatus (10) according to any of the preceding claims, wherein the functional components further comprise: - an exhaust gas heat exchanger (32), which is adapted to extract heat from the exhaust gas flow, and / or - a thermoelectric generator (28) and / or - a silencer element (56).

6. Apparatus (10) according to any of the preceding claims, wherein the functional components further comprise: - a feed device (46) for feeding combustion air to the fireplace.

7. Apparatus (10) according to claim 6, wherein the combustion air feed device (46) comprises at least one of: - a heating unit for the combustion air, in particular a heat exchanger, which is configured and adapted to transfer heat from the centrifugal separator unit (38) and / or pipes through which exhaust gas flows to the combustion air; and - a second mechanical flap unit for controlling the flow rate of combustion air.

8. Apparatus (10) according to any of the preceding claims, wherein the control unit (52) is further adapted to control at least one of the functional components and / or at least one of the flap arrangements (20).

9. Apparatus (10) according to claim 8, wherein the control unit (52) is also accommodated within the housing.

10. Apparatus according to any of the preceding claims, wherein a positioning device is assigned to the housing (12), in particular height-adjustable feet and / or an apparatus for attaching to an external component.

11. Apparatus according to any of the preceding claims, wherein the housing (12) is designed to be fireproof.

12. Apparatus according to any of the preceding claims, further comprising a cleaning connection for an ash vacuum cleaner in the region of the centrifugal separator unit (38).

13. System for heating a room, comprising a fireplace, an apparatus (12) coupled to the fireplace by its inlet section (14) according to any of the preceding claims, and possibly a chimney coupled to the outlet section (16).