DE102021116212A1 - Heater, method for its operation and use of a particle separation device - Google Patents

Abstract

Heating device (1), at least comprising a burner (2) with a combustion air supply (3) and a fuel supply (4), characterized in that a combustion air supply (3) is assigned at least one particle separator (5), which particles from a flow of combustion air can remove. Furthermore, a method for operating a heating device (1) and the use of a particle separation device (5) are proposed.

Description

The present invention relates to a heating device, at least comprising a burner with a combustion air supply and a fuel supply. In particular, the invention relates to the field of condensing heaters. Furthermore, a method for operating a heater is proposed, as well as an advantageous use of a particle separation device in a heater.

Condensing boilers are used in particular for hot water heating, with the energy generated during combustion being converted almost completely. In particular, the exhaust gas produced during combustion is cooled as far as possible and the heat contained in it is used completely for heating the water by means of a condensation heat exchanger. Different types of fuel can be used for such combustion, with an increasing proportion of hydrogen or even pure hydrogen being able to be used for the combustion.

During the operation of such a heater, so-called flashbacks can occur, with the flame front, which is usually formed in the combustion chamber, propagating along the fuel supply counter to the direction of flow. It is obvious that such an uncontrolled combustion or explosion taking place outside the combustion chamber is dangerous and should be avoided.

As a safety measure that makes sense for this purpose, a so-called flame barrier is installed in the area of the combustion air and/or fuel supply, which is intended to prevent the flame front from spreading beyond this component. Porous bodies and/or bodies having a large number of channels are particularly suitable for such flame barriers. Sinter powder, metal layers, etc. can be used to produce such flame barriers. What the flame barriers have in common is that they massively reduce the flow cross-section and thus only allow combustion air and/or fuel to enter through micro-channels or micro-pores.

The maintenance of such a flame arrester can be expensive, especially if it has to be done frequently. The reason for this may be an undesirably high pressure drop across the flame arrestor, so that it may not always be possible to maintain an exact metering or supply of the combustion air/fuel mixture.

Proceeding from this, it is the object of the present invention to at least partially solve the problems described with reference to the prior art. In particular, a heater is to be specified which implements continuous operation with increased safety using simple design measures. In addition, the operation and the heater should be easier to maintain. It would also be desirable if the improvement could be readily incorporated into known heater designs.

These objects are achieved with a heater according to the features of patent claim 1, a method for operating a heater according to patent claim 8 and/or use of a particle separation device according to the features of patent claim 10. Further advantageous configurations are specified in the dependent patent claims. The features mentioned in the patent claims can be combined with one another in any technologically meaningful way and show further embodiment variants of the invention. The description, in particular in connection with the figures, explains the features of the invention and specifies further exemplary embodiments.

A heater that includes at least one burner with a combustion air supply and a fuel supply contributes to this. The heater is in particular a so-called condensing heater. The combustion air supply can be designed in particular in the form of a duct or line arrangement, which ultimately extends to the burner or combustion chamber. The fuel supply can also be designed in the form of a duct or a line that leads to the burner. It is possible for a combustion air supply and a fuel supply to at least partially form a common mixture line. A mixing unit or a gas valve is usually provided, with which the fuel can be added to the supplied combustion air supply.

With regard to the fuel supply, it is basically possible for the fuel to be supplied in solid, liquid or gaseous form. In the present case, it is in particular a gaseous fuel, which may be partially or completely made up of hydrogen.

The combustion air supply is usually designed in such a way that it includes an inlet that can interact with the ambient air of the heater. This entry can be positioned within a housing of the heater and/or directly on the housing of the heater. In other words, this means in particular that ambient air is used as the combustion air. Since such heaters are mostly in storage rooms, basement rooms, etc., there is a risk that a significant proportion of dust, dirt or similar particles will be sucked in via this ambient air and moved towards the burner.

In particular with the aim of removing the particles or dust sucked from the environment and thus not prematurely clogging the pores or microchannels of the flame arrestors, the combustion fan is assigned at least one particle separator which can remove particles from a flow of the combustion air. In many cases it is considered sufficient that a single particle separation device is provided for the heater. However, it is also possible for a heater to be designed with several, possibly even different, particle separation devices. The embodiments of the particle separation device will be discussed in detail below.

Such a particle separation device can be positioned in the combustion air supply (or even in the common mixture line). It is possible for a particle separation device to be positioned at or in the inlet of the combustion air supply. It is possible for the particle separation device to be positioned at a distance from the inlet of the combustion air supply, but in or on a housing of the heater. The particle separating device is provided in particular in such a way that a large part of the combustion air supplied to the burner passes or flows through this particle separating device. It is possible for the entire combustion air flow to flow through at least one particle separation device. The particle separating device can be designed in such a way that it can separate (floating or entrained) particles of the intake combustion air flow or remove them from the flow. It is preferred that, for example, particles with a particle diameter of less than 150 μm [microns], in particular in the range from 10 to 100 μm, and preferably in a proportion of at least 60%, are removed from the combustion air flow.

The at least one particle separation device can be arranged on and/or in the combustion air supply. In this respect, the particle separation device can also extend to walls or wall sections or cavities of the combustion air supply. It is possible for the particle separation device to be (at least partially) integrated into the combustion air supply. It is possible for a particle separation device to be mountable on or in the combustion air supply in the manner of a separate component set.

The at least one particle separation device can comprise at least one filter. This can be a so-called “mechanical” filter, for example, which is formed, for example, with paper and/or metal and/or in the manner of a fabric. Such a filter can be arranged, for example, in or on the housing inlet, in/at the inlet of the combustion air supply and/or in or on the mixture line between a fan and the burner or the flame arrester.

It is possible that the at least one particle separation device comprises at least one cyclone separator or one inertial separator. A cyclone separator, sometimes also called a centrifugal separator, is used to remove or separate solid particles contained in the combustion air. The structure essentially comprises four components, namely an (upper) intake cylinder, a (central) cone, a particle collection container (also called a bunker, below) and a so-called immersion tube, which is attached centrally from above in the intake cylinder. In the intake cylinder, the combustion air-particle mixture is blown in or sucked in, in particular, tangentially and is thus brought onto a circular path. Due to the narrowing in the subsequent cone, the rotational speed increases to such an extent that the particles are pressed against the walls of the cone by centrifugal force or are thrown there. The combustion air, which flows centrally, is therefore essentially free of particles and can leave the separator through the central immersion tube. A cyclone separator can be provided in particular at the inlet of the combustion air supply.

In principle, an inertia separator works in a similar way, although the tangential flow is not important here, but another (abrupt) change in the flow movement is set, which the particles cannot follow due to their inertia. It is possible to provide an inertial separator directly on the housing of the heater, for example where the ambient air inlet is. This offers the particular advantage that the particle collection area is easily accessible and can be emptied or cleaned from the outside by the users themselves. It is possible to provide the inertia separator in the combustion air supply itself, which can also use gravity, for example. In particular, it is possible to implement a significant cross-sectional jump in the combustion air supply, so that the flow rate drops sharply and the dust can fall out.

It is possible that essentially the heater or its (entire) housing is designed in the manner of an inertial separator. For this purpose, guide structures or guide plates can be provided in the housing of the heater, which forms a targeted, possibly meandering flow of the combustion air after entering the housing of the heater up to the entry of the combustion air supply. The bottom of the heater housing can thus form a collection area for the particles. The guide structures are arranged in particular within the housing of the heater in such a way that the ambient air first flows downwards and only then reaches the inlet (positioned further up) for the combustion air supply. In particular, the provision of such guide structures can also ensure that the flow path of the combustion air is significantly lengthened from the entry into the housing to the entry of the combustion air supply, for example by a factor of 2 or even 3.

It is possible that the at least one particle separation device comprises at least one electrical particle charging apparatus. It is possible for such a particle separation device to include what is known as an electrostatic precipitator. In particular, it is provided that the electrical particle charging apparatus includes a discharge electrode which is suitable for forming an electrical field with which dust particles in the combustion air can be electrically charged. The charged dust particles can then migrate through the effect of the electrical force (Coulomb's law) of an applied DC voltage field transverse to the direction of flow of the combustion air to a given collection electrode, where they release their electrical charge. After the particles have then given up their electrical charge, they are bound by holding forces or adhesive forces, which are essentially determined by the electrical field.

It is possible for such an “active static charge” to build up in an area close to where the combustion air enters the heater housing. The particle charging apparatus is set up in particular for the static charging of dust particles, with the particles preferably also being deposited or collected there at the same time.

The at least one particle separation device can comprise at least one passively electrically charged surface. A passively electrically charged surface is in particular designed in such a way that it is suitable for electrostatic charging of particles in the combustion air, in particular due to the fact that they flow past. The surface can have suitable materials, surface properties, etc. for this purpose. In particular, it is possible for the passively electrically charged surface to include microfibers. The microfibers can be synthetic fibers such as formed from nylon and/or polyester.

In principle, all surfaces in the interior of the heater or its housing around which the combustion air flows can be designed with such passively electrically charged surfaces. It is possible to cover existing walls with such a surface, but it is also possible to resuspend or arrange such passively electrically charged surfaces in the housing of the heater. It is possible, for example, to form a kind of curtain with such a passively electrically charged surface, particularly in the area where the combustion air enters the heater housing. It is also possible, for example, to design side areas of the heater housing, where insulating mats are currently located, with corresponding passively electrically charged surfaces. It is also possible to design outer surfaces of the heat exchanger and/or an expansion tank and/or other components in the area where the combustion air enters the housing with corresponding passively electrically charged surfaces.

The invention is preferably used in a heating device in which at least one flame arrester is provided upstream of the burner in the combustion air supply, to which combustion air treated by the at least one particle separation device can be supplied. Consequently, it is possible in this way for particles to first be removed from the combustion air and only then for the combustion air to flow through the flame arrestor.

1. a) Zuführen von wenigstens teilweise Partikel aufweisende Verbrennungsluft zu einem Heizgerät;
2. b) wenigstens teilweises Entfernen der Partikel aus der Verbrennungsluft;
3. c) Verbrennen eines Gemisches aus Brennstoff und Verbrennungsluft.

According to a further aspect of the invention, a method for operating a heating device is proposed, comprising at least the following steps:

1. a) supplying combustion air at least partially containing particles to a heating device;
2. b) at least partially removing the particles from the combustion air;
3. c) Combustion of a mixture of fuel and combustion air.

The explanations for the heating device and the functional and structural features of the particle separation device can also be used to describe this method for operating the heating device. In particular, the particle separation device in the installed design continuously carries out the method steps a) to c) during operation of the heater.

Step a) includes, in particular, sucking in ambient air in the vicinity of the heater. For this purpose, the heater can be designed with a fan or the like. The combustion air or ambient air regularly includes particles such as dust, exhaust gas particles, etc., which are also sucked in here.

Step b) can be carried out in particular by means of one of the particle separation devices presented here. The combustion air, at least partially cleaned of particles in this way, is then fed to the heater together with the fuel, so that this combustible mixture is then burned in the combustion chamber.

In this case, the method is designed in particular in such a way that the combustion air is guided through at least one flame arrester after step b) and before step c). Step b) thus contributes to the fact that the flame barrier does not clog or clogs significantly later than in the prior art, which leads to improved ease of maintenance.

Finally, according to a further aspect, the use of a particle separation device to reduce the particle loading of a combustion air stream of a heating device is proposed, in particular to improve the functionality of a flame arrestor of the heating device. The explanations for the heater can also be used to characterize the use of the particle separation device and vice versa.

• 1: ein Heizgerät mit einer ersten Ausführungsform einer Partikelabscheidevorrichtung,
• 2: ein Heizgerät mit einer zweiten Ausführungsform einer Partikelabscheidevorrichtung,
• 3: eine weitere Ausführungsvariante einer Partikelabscheidevorrichtung, die oben am Gehäuse ausgeführt ist,
• 4: eine mögliche Ausführungsform einer Partikelabscheidevorrichtung gemäß 3,
• 5: ein weiteres Ausführungsbeispiel einer Partikelabscheidevorrichtung,
• 6: ein Gehäuse eines Heizgerätes mit einer Partikelabscheidevorrichtung, umfassend eine Leitstruktur,
• 7: ein weiteres Ausführungsbeispiel einer Partikelabscheidevorrichtung mit einer elektrischen Partikelaufladeapparatur, und
• 8: ein Ausführungsbeispiel einer Partikelabscheidevorrichtung mit wenigstens einer passiv elektrisch geladenen Oberfläche.

The invention and the technical environment are explained in more detail below with reference to the figures. It should be pointed out that the figures show exemplary embodiments to which the invention should not be restricted. The individual features from the figures can be extracted and combined with further explanations of the general description or aspects of other figures, unless this is explicitly excluded here. In particular, components that are not provided with reference symbols are of secondary or even negligible importance for the description of the invention. The same facts are given the same reference symbols in the figures, so that their explanations can be used from other descriptions of the figures, even if they have not been explained (again). The figures are schematic and show the following:

• 1 : a heater with a first embodiment of a particle separation device,
• 2 : a heater with a second embodiment of a particle separation device,
• 3 : another embodiment variant of a particle separation device, which is designed at the top of the housing,
• 4 : a possible embodiment of a particle separation device according to FIG 3 ,
• 5 : another embodiment of a particle separation device,
• 6 : a housing of a heater with a particle separation device, comprising a guide structure,
• 7 : a further exemplary embodiment of a particle separation device with an electrical particle charging apparatus, and
• 8th : an embodiment of a particle separation device with at least one passively electrically charged surface.

1 shows schematically the (internal) structure of a heating device 1, which is usually encapsulated by a housing 12, various components of the heating device 1 being arranged in the housing interior 22 located therein. At the top, for example, an exhaust pipe 21 can be led out of the housing 12 , with at least one entry possibility for the ambient air (combustion air) located outside of the housing 12 being provided in the area surrounding this exhaust pipe 21 . As shown by the arrows (also roughly illustrating a flow path 19 in the following figures), the ambient or combustion air can enter the housing 12 there, where it can be prefiltered there, for example, directly by different or multiple particle separation devices 5 . In particular, mechanical filters 6 can be provided here.

The combustion air then flows further along the indicated flow path 19 in the housing interior 22 to the inlet 15 of the combustion air supply 3. A particle separation device 5 can also (alternatively or cumulatively) be provided at this inlet 15, for example again in the form of a filter. The combustion air then flows on the inside through the combustion air supply 3, which is designed here in the manner of a silencer. This combustion air then reaches a mixing unit 14, which is also associated with the fuel supply 4. Consequently, the fuel is added to the combustion air in a predetermined ratio in the mixing unit 14 and then conducted together to the central section of the heat exchanger 13, where on the one hand a flame arrester 11 and behind it a burner 2 are positioned. In the exemplary embodiment shown here, a further particle separation device 5 is provided in the common mixture line downstream of the mixing unit 14 on the inside. For this flow path 19 of the combustion air, a blower (only shown hidden here) can be provided, with which the ambient air is sucked in, moved through the combustion air supply 3 and fed to the burner 2 .

In principle, it is possible to provide the other particle separation devices disclosed here at the same or similar positions as illustrated here.

2 shows an embodiment of a particle separation device 5 in the manner of a cyclone separator 7. This is in turn provided at the inlet area of the combustion air supply 3. FIG. The combustion air first flows tangentially into the upper area of the cyclone separator 7 (inlet 15), then undergoes a twist, with the particles 23 contained therein falling down in the conical middle compartment, where they are ultimately collected in the collection area 17. The combustion air is then discharged centrally and upwards via the outlet 16 and fed directly to the combustion air supply 3, which then has fewer or hardly any particles.

3 and 4 show an embodiment of a particle separation device 5, which is designed concentrically around the exhaust pipe 21 and is constructed according to the principle of an inertial separator 8. The ambient air sucked into the housing 12 over the circumference of the exhaust pipe 21 is deflected radially in the process, with the particles 23 being collected in the central collection area 17 on the end face due to their inertia. 4 shows in detail that the incoming combustion air hits an impact surface, which here in particular forms the inlet 15, and is then discharged radially, a recess being provided in the inertial separator 8, in which the particles 23 are then collected (collection area 17). The radial outflow is achieved via channels that form an outlet 16 .

5 shows a variant of a particle separation device 5 in the manner of an inertial separator 8, which is integrated into the combustion air supply 3. It is characterized in that initially the cross section of the combustion air supply 3 is significantly expanded, which leads to a slowing down of the flow. Furthermore, the overflow of clean combustion air is adjusted by the shape of the combustion air supply 3 and the separation of particles 23 in a collection area 17 is promoted.

6 shows the integration of an air baffle, which forms a guide structure 18 and also (alternatively) a collection area 17, in the housing 12, so that a particle separation device 5 is formed. In particular, this ensures that the flow path 19 takes a significant detour from the area where the ambient air enters the housing 12 to the entry 15 into the combustion air supply 3, whereby it also extends significantly deeper into the entry 15 of the combustion air supply 3 to be led.

7 FIG. 1 shows another exemplary embodiment of a particle separation device 5, which is designed with an electrical particle charging apparatus 9. FIG. This is connected to an electrical voltage source 20 and positioned or set up in such a way that it can electrically charge the ambient air flowing past there or the particles 23 contained therein. The (dust) particles 23 electrically charged in this way can then be captured on a corresponding separation surface or separation electrode.

8th 1 shows by way of example that passively electrically charged surfaces 10 form a particle separation device 5 inside the housing 12 . The combustion air first flows back through the housing 12 (see arrow or flow path 19) and then flows onto surfaces of the heat exchanger 13, the combustion air supply 3 and/or boundary walls of the housing 12, where passively electrically charged surfaces 10 can be provided everywhere. It is also possible to provide a kind of curtain of (movable, flap-like) passively electrically charged surfaces 10 at the top of the housing 12, which the incoming flow has to pass through.

It has thus been disclosed how the problems described with reference to the prior art have been at least partially solved. In particular, a heater has been described which implements continuous operation with increased safety using simple design measures. In addition, the operation and the heater itself are now easier to maintain. In addition, measures were specified that can easily be integrated into known constructions of heaters.

Reference List

1

heater

2

burner

3

combustion air supply

4

fuel supply

5

particle separator

6

filter

7

cyclone separator

8th

inertial separator

9

electrical particle charging apparatus

10

passively electrically charged surface

11

flame arrestor

12

Housing

13

heat exchanger

14

mixing unit

15

entry

16

exit

17

collection area

18

lead structure

19

flow path

20

voltage source

21

exhaust pipe

22

housing interior

23

particles

Claims (10)

Heating device (1), at least comprising a burner (2) with a combustion air supply (3) and a fuel supply (4), characterized in that a combustion air supply (3) is assigned at least one particle separation device (5), which particles from a flow of combustion air can remove. heater (1) after claim 1 , characterized in that the at least one particle separator (5) is arranged on or in the combustion air supply (3). Heating device (1) according to one of the preceding claims, characterized in that the at least one particle separation device (5) comprises at least one filter (6). Heating device (1) according to one of the preceding claims, characterized in that the at least one particle separator (5) comprises at least one cyclone separator (7) or inertial separator (8). Heating device (1) according to one of the preceding claims, characterized in that the at least one particle separation device (5) comprises at least one electrical particle charging apparatus (9). Heating device (1) according to one of the preceding claims, characterized in that the at least one particle separation device (5) comprises at least one passively electrically charged surface (10). Heater (1) according to one of the preceding claims, characterized in that at least one flame arrester (11) is provided upstream of the burner (2) in the combustion air supply (3), to which combustion air treated by the at least one particle separation device (5) can be supplied. Method for operating a heating device (1), comprising at least the following steps: a) supplying combustion air at least partially containing particles to a heating device, b) at least partial removal of the particles from the combustion air, c) Combustion of a mixture of fuel and combustion air. procedure after claim 8 , in which the combustion air is passed through a flame arrestor (11) after step b) and before step c). Use of a particle separation device (5) to reduce the particle load in a combustion air flow of a heater (1) to improve the functionality of a flame arrestor (11) of the heater (1).

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